J Basic Clin Physiol Pharmacol 2016; aop
Dilip Chandrasekhar*, Jaffer Chalilparambil, Sajitha Mukriyan Kallungal, Danisha Pattani, Abin Chandrakumar and Vikas Pokkavayalil
Prevalence, risk factors and antimicrobial susceptibility pattern of extended spectrum β-lactamase-producing bacteria in a tertiary care hospital DOI 10.1515/jbcpp-2015-0020 Received March 3, 2015; accepted November 13, 2015
Abstract Background: The widespread misuse of antibiotics over the past several decades has been regarded as the contributing factor in the development of resistance toward them. Extended spectrum β-lactamases (ESBLs) are enzymes produced by certain bacteria that can make them resistant to certain antibiotics. Early detection of ESBL strains and judicious use of antibiotics and proper implementation of infection control strategies are essential to prevent the spread of this threat in the community. The study aimed at appraising the prevalence, risk factors and antimicrobial susceptibility pattern of ESBL-producing microorganisms. Methods: A prospective observational study was carried out in a tertiary care referral hospital located in Malappuram district of Kerala among inpatients with infection by ESBL-producing bacteria in order to estimate the prevalence, risk factors and their antibiotic susceptibility pattern. Results: Out of the total 1156 patients studied, 118 had confirmed diagnosis on the presence of ESBL-producing microorganisms. Overall, 9.79% of all samples growing Enterobacteriaceae yielded an ESBL producer. Out of the total isolates identified, 66.1% were urinary tract infections, 15.1% were respiratory tract infections, 14.4% were surgical site infections and the remaining constituted *Corresponding author: Dilip Chandrasekhar, Professor and Head, Department of Pharmacy Practice, Al Shifa College of Pharmacy, Poonthavanam, P.O. Perinthalmanna, Kerala-679325, India, E-mail: [email protected] Jaffer Chalilparambil: Department of General Medicine, KIMS Al Shifa Hospital, Perinthalmanna, Kerala, India Sajitha Mukriyan Kallungal, Danisha Pattani, Abin Chandrakumar and Vikas Pokkavayalil: Department of Pharmacy Practice, Al Shifa College of Pharmacy, Poonthavanam, Kizhattur, P.O. Perinthalmanna, Kerala, India
blood stream infections. The highest antimicrobial activity against ESBL-producing isolates was observed for meropenem. Conclusions: High prevalence of ESBL-producing organisms is evident in the study setting implicating the necessity to report the ESBL production along with the routine sensitivity reports supplemented with control measures which can assist a clinician in prescribing appropriate antibiotics. Keywords: antimicrobial susceptibility; prevalence; risk factors.
Introduction Antibiotics are substances produced by microorganisms, which suppress the growth of or kill other microorganisms at very low concentrations [1]. The discovery of antimicrobial agents (AMA) was one of the greatest medical triumphs of the 20th century and has become one of the most commonly prescribed groups of drugs in modern practice. The antibiotic era started in the 1940s and changed the profile of infectious diseases and human demography [2]. Starting with the introduction into the medical practice of the sulfonamides in the 1930s, penicillin and streptomycin in the 1940s, the broad spectrum bacteriostatic antibiotics during the 1950s, followed by bactericidal antibiotics in the 1960s, together with other important synthetic chemicals and highly specific narrow spectrum antibiotics during these years, the AMA revolutionized the treatment of bacterial diseases [3]. Antibiotic resistance is a public health problem. The foundation of modern medicine is built on the availability of effective antibiotics, especially in economically deprived areas of the world where the disease burden due to bacterial infections remains high. Antibiotic resistance is predominantly fueled by antibiotic use. The regular
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
2 Chandrasekhar et al.: Antimicrobial susceptibility pattern of ESBL-producing bacteria introduction of new antibiotic classes over the years has partly masked the problem of increasing resistance. However, this is no longer the case today because the pipeline for newer antibiotics is nearly empty. Therefore, we need to preserve the currently available antibiotics for use by future generations. The World Health Organization and European Commission have recognized the importance of studying the emergence and determination of resistance and the need for control strategies [4]. Infections are defined as community onset if they occur within 48 h of admission in a patient with no hospital admissions in the past 12 months, and health care associated if onset is within 48 h of admission in a patient who, in the preceding year, had (i) been admitted to hospital, (ii) resided in a nursing or residential home, or (iii) required intravenous chemotherapy or hemodialysis. Hospital-onset ESBL infections are defined as occurring more than 48 h after admission. AMA are one of the most commonly prescribed groups of drugs for treating various infectious diseases. The widespread use and sometimes the misuse of antibiotics in all health care facilities over the past several decades have been regarded as the contributing factor in the development of resistance toward them. ESBLs are enzymes produced by certain bacteria that can make them resistant to certain antibiotics. These enzymes produce resistance to a variety of β-lactam antibiotics including extended spectrum penicillins, third generation cephalosporins and monobactams. They often show cross-resistance to many other classes of antibiotics such as fluoroquinolones and amino glycosides by additional mechanisms, thus further limiting treatment options. At present, ESBLs have been increasing as a serious nosocomial and community pathogen having the property of multidrug resistance. With this in mind, the early detection of ESBL strains and judicious use of antibiotics and proper implementation of infection control strategies are essential to prevent the spread of this threat in the community. The following study was aimed at estimating the prevalence, risk factors and antimicrobial susceptibility pattern of ESML-producing microorganisms.
Materials and methods The study was of prospective-observational design and was performed in a tertiary care referral hospital, located in the city of Perinthalmanna in Malappuram District, Kerala. The study was conducted over the duration of 1 year from March 2013 till February 2014. The study protocol was approved by the Institutional Ethical Committee. All patients for whom antimicrobial culture sensitivity was ordered
by the physician were screened to identify patients with ESBL positive culture result. These ESBL patients were included in the study irrespective of their age, sex and department of admission. Patients for whom adequate data were missing from the file and those who denied consent for participation were excluded from the study. The data for the study were obtained through patient interviews and analysis of case sheets. The culture sensitivity reports were obtained from the microbiology lab for each patient. These data were entered into a pre-designed data form. The site of isolation, species of bacteria and antimicrobial resistance pattern were recorded and multiple sites of isolation, if performed, were separately recorded. But successive cultures from the same patient were excluded to avoid duplication. Data on the risk factor for infection with ESBL-producing organisms were collected and assessed. A total of 12 commonly used AMA, which represent the most commonly used antibiotics in our hospital, were selected for the study. The data obtained during the study period were analyzed for estimates of overall prevalence of ESBL-producing microorganisms, stratification on the basis of setting of acquiring infection (community acquired, health care associated and hospital acquired), identification of the risk factors contributing toward the development of resistance, distribution pattern ESBL-producing microorganisms and department-wise distribution and resistance/susceptibility pattern of pathogens toward the commonly used AMA. SPSS 17 for windows version was used to perform statistical analysis. Numerical data are expressed as mean and standard deviation. The frequency distribution of parameters such as gender, department, type of infection and organism isolated was also analyzed. For categorical variables, frequencies and percentages were computed with a χ2-test. For quantitative variables, a paired t-test was used. Results were interpreted with a p-value, which is the probability of accepting the null hypothesis. The significant level was set at 70
51 2 1 10 1 23 26
– – – – 3 6 9
– – – 7 4 1 5
– – – – 3 1 2
BSI, Blood stream infections; RTI, respiratory tract infections; SSI, surgical site infections; UTI, urinary tract infections.
statistical significance using a χ2-test for the null hypothesis that there was no difference between the distribution of male and female in different age groups. The χ2-value obtained was 7.712 (p = 0.173), showing that there was no significant difference and proving the null hypothesis true. The length of hospital stay (in terms of days) ranged from 0 to 5 for 12.7% (n = 15), 6 to 10 for 56.8% (n = 67), 11 to 15 for 22.9% (n = 27) and 16 to 20 for 7.6% (n = 9). The comorbidities in patients with ESBL-producing isolates were diabetes in 56.78% (n = 67), hypertension in 40.68% (n = 48), renal failure in 21.18% (n = 25) and 5.93% (n = 7) each in both cirrhosis and coronary artery disease. The testing of null hypothesis that the distribution of comorbidities was equal in different infections for which ESBL-producing organisms were isolated (Table 4) was performed using a χ2-test which yielded a value of 28.49 (p = 0.019), showing that there was a significant difference in the distribution of comorbidities. A number of patients having prior exposure to antibiotics in each type of infection (Table 5) were tested for the null hypothesis that the number of exposed and unexposed groups was equal in the different types of infection. A χ2-test was used for the hypothesis testing and the value obtained was 10.37 (p = 0.016), which depicts that there is significant difference between the exposed and non-exposed groups. The hypothesis testing was done on the data in Table 6 to estimate the difference between patients who had a history of ICU admission and those who did not, toward developing ESBL-producing organisms in different infection groups. The null hypothesis that there existed no difference was tested by a χ2-test and yielded a value of 23.202 (p = 0.0001), which reveals that there is a highly significant difference between the two groups. Data from Table 7 on the resistance to different classes of antibiotics show high resistance rates to cefotaxime (100.0%), amoxicillin-clavulanic acid (95.8%), ciprofloxacin (79.7%) and co-trimoxazole (65.3%). The data also showcase the high sensitivity of ESBL-producing
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
4 Chandrasekhar et al.: Antimicrobial susceptibility pattern of ESBL-producing bacteria 100%
100%
100%
Female
Male
90% 80%
70.6% 63.4%
70%
57.7%
60% 50%
45.2%
42.3%
40%
54.8% 36.6%
29.4%
30% 20% 10%
0%
0%
0%
Infant
1–10
11–50
51–60
61–70
Above 70
Age distribution, years → Figure 1: Simple bar graph representing subject distribution with respect to gender within each age group.
Table 4: Comparison between the type of infections with respect to comorbidity.
Table 6: Frequency distribution of the previous history of ICU admission.
Comorbidity
Infections
Diabetes
Hypertension Renal failure COPD Cirrhosis Coronary artery disease
UTI 40 59.70% 36 75% 22 88.0% 3 42.86% 5 71.43% 3 60.00%
RTI
12 17.91% 8 16.67% 3 12.0% 4 57.14% 1 14.28% 1 20.00%
SSI
12 17.91% 4 8.33% 0 0% 0 0% 0 0% 0 0%
BSI
3 4.47% 0 0% 0 0% 0 0% 1 14.28% 1 20.00%
Total
67 100.0% 48 100.0% 25 100.0% 7 100.0% 7 100.0% 5 100.0%
BSI, Blood stream infections; COPD, chronic obstructive pulmonary disease; RTI, respiratory tract infections; SSI, surgical site infections; UTI, urinary tract infections.
Table 5: Frequency distribution of prior subject exposure to antibiotic in each type of infection. Infections
UTI RTI SSI BSI Total
Previous exposure to antibiotics No
Yes
65 5 1 3 43
13 13 16 2 75
Total
78 18 17 5 118
BSI, Blood stream infections; RTI, respiratory tract infections; SSI, surgical site infections; UTI, urinary tract infections.
UTI RTI SSI BSI Total
History of admission in ICU Negative 65 13 5 5 88
Total
Positive
13 5 12 0 30
78 18 17 5 118
BSI, Blood stream infections; RTI, respiratory tract infections; SSI, surgical site infections; UTI, urinary tract infections.
isolates toward meropenem (100.0%), followed by piperacillin-tazobactam (92.4%), cefoperazone-sulbactam (90.7%) and amikacin (88.1%). The sensitivity patterns of the three major isolates, namely E. coli, Klebsiella and Enterobacter against various a ntibiotics is represented through Table 8.
Discussion Infections caused by ESBL-producing bacteria have become a serious concern worldwide, indicating that continuous monitoring systems and effective infection control measures are quintessential. Their presence supplemented with the potential for plasmid-mediated carbapenem resistance can catapult significant therapeutic dilemma in the future. β-Lactam antibiotics account for approximately 50% of global antibiotic consumption, and this heavy usage has accelerated the resistance rates.
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
Chandrasekhar et al.: Antimicrobial susceptibility pattern of ESBL-producing bacteria 5 Table 7: Resistance or susceptibility pattern of microorganisms. Antibiotic
Resistant Frequency
Meropenem Cefoperazone-sulbactam Piperacillin-tazobactam Amikacin Amoxicillin-clavulanic acid Cefotaxime Ciprofloxacin Co-trimoxazole Gentamicin Chloramphenicol Doxycycline Tobramycin
Percentage
0 11 9 14 113 118 94 77 50 18 68 50
0% 9.3% 7.6% 11.9% 95.8% 100.0% 79.7% 65.3% 42.4% 15.3% 57.6% 42.4%
Sensitive Frequency
Percentage
118 107 109 104 5 0 24 41 68 100 50 68
100.0% 90.7% 92.4% 88.1% 4.2% 0% 20.3% 34.7% 57.6% 84.7% 42.4% 57.6%
Table 8: Sensitivity pattern of different microorganisms isolated in each antibiotic. Antibiotic
Sensitivity E. coli Frequency
Meropenem Cefoperazone-sulbactam Piperacillin-tazobactam Amikacin Amoxicillin-clavulanic acid Cefotaxime Ciprofloxacin Co-trimoxazole Gentamicin Chloramphenicol Doxycycline Tobramycin
67 63 63 65 4 0 8 22 42 62 26 42
Klebsiella
Percentage
100.0% 92.6% 92.6% 95.59% 5.82% 0% 11.76% 32.36% 61.76% 91.18% 38.23% 61.76%
Enhanced infection control coupled with antibiotic stewardship programs can play a pivotal role in limiting the spread of ESBL-producing organisms. In addition, infection with ESBL-producing bacteria raises mortality leading to prolonged hospital stays supplemented with increased relative treatment costs. Therefore, it is crucial to assess the risk factors for the emergence of ESBL-producing bacteria, and to establish practices which barricade against such resistance. This study delineates the microbiological spectrum of ESBL-producing Enterobacteriaceae, their antimicrobial resistance patterns and the clinical characteristics of patients associated with these infections in a tertiary care teaching hospital. The pattern of resistance can vary internationally, and even locally, between the institutions. Institution-specific surveillance of ESBL prevalence and susceptibility of these pathogens to commonly used antibiotics can catalyze to
Frequency
39 34 35 33 0 0 15 13 22 31 19 20
Enterobacter
Percentage
100.0% 87.17% 89.74% 84.61% 0% 0% 38.46% 33.33% 56.41% 79.48% 48.71% 51.28%
Frequency
10 9 9 5 01 0 1 3 4 6 4 5
Percentage
100.0% 90.0% 90.0% 50.0% 10.0% 0% 10.0% 30.0% 40.0% 60.0% 40.0% 50.0%
enhance patient outcome and preserve the efficacy of the available antibiotic agents. During the study duration spanning one year, a total of 118 hospitalized patients presented non-duplicate clinical isolates positive for ESBL-producing bacteria. A total of 1156 blood, urine, wound and sputum samples were processed during the time frame. Overall, 9.37% of all samples growing Enterobacteriaceae yielded an ESBL producer. This prevalence rate was relatively lower in comparison to the study conducted by Thenmozhi and Sureshkumar [5] and higher than those reported in different studies carried out by Enoch et al. [6] and Schoevaerdts et al. [7]. Reasons for such high rates of resistance may be lack of standard antibiotic guidelines for the treatment of microbiological infections, poor drug quality, increased transmittance rate of infection through hospitalized patients, bystanders or staff, unscientific allocation of infective patients
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
6 Chandrasekhar et al.: Antimicrobial susceptibility pattern of ESBL-producing bacteria and antibiotic abuse due to the easy availability of antibiotics without prescriptions. Onset of infection caused by the ESBL producer was categorized as hospital, community and health care associated in 31 (26.27%), 41 (34.75%) and 46 (38.98%) patients, respectively. Identical studies by Enoch et al. [6] revealed that majority of infections come under health care-associated [67 (54.03%)], followed by community- [31 (25.0%)] and hospital-acquired [26 (20.97%)] infections. The most common site of isolation was urine, followed by respiratory tract. This may be due to the fact that urinary tract infections are the most frequent infections worldwide among the hospitalized patients, and Enterobacteriaceae are generally the causative agents. The four documented infections were urinary tract infection 78 (66.1%), respiratory tract infection 18 (15.2%), surgical site infection 17 (144%) and blood stream infection 5 (4.2%). The predominance of urine samples is consistent with the results of the study carried out by Fennell et al. [8], Peralta et al. [9] and Schoevaerdts et al. [7]. However, there were observable differences from the results of the study carried out by Sarojamma et al. [10], where a greater proportion of ESBL was reported from blood, followed by stool, sputum, urine and pus samples. The departments with the highest number of positive ESBL-producing isolates were general medicine 48 (40.70%) and nephrology 21 (17.80%), as they had higher number of in-patients during the study period. Urinary tract and respiratory tract infections were the two major diagnostic categories and constituted the most frequent types of infection among elderly patients admitted in general medicine departments. This result obtained is consistent with the result of the study carried out by Rubio-Perez et al. [11], but different from the study of Schoevaerdts et al. [7], in which majority of the patients were admitted to the surgery department. The most frequently isolated pathogen was E. coli 68 (66.1%), followed by Klebsiella 39 (33.05%), Enterobacter 10 (8.47%) and Pseudomonas 1 (0.85%). This result obtained was consistent with the result of the study carried out by Fennell et al. [8], Rubio-Perez et al. [11], Enoch et al. [6] and Rivard-Yazigi et al. [12]. In case of urinary tract infection out of the 78 cases, E. coli constituted 51 (65.38%) of the urinary tract infections isolates, followed by Klebsiella 22 (28.20%) and Enterobacter 5 (6.41%). Escherichia coli was more frequently found in association with urinary tract infection; this was in line with the result of the study carried out by Schoevaerdts et al. [7] and Khan et al. [13]. In the current study, the presence of ESBL-producing E. coli amongst the urine specimens is of grave concern, since E. coli is the main causative agent of urinary tract infections, and
consequently, there is widespread use of AMA due to such infections. In respiratory tract infection, Klebsiella (n = 12, 66.67%) was the most commonly isolated organism, followed by E. coli (n = 5, 27.77%) and Enterobacter (n = 1, 5.5%). Out of the 17 surgical site infections studied, E. coli was predominant isolate (n = 7, 41.17%), followed by Klebsiella (n = 5, 29.41%), Enterobacter (n = 4, 23.52%) and Pseudomonas (n = 1, 5.88%). Escherichia coli was the organism responsible for all the blood stream infections which came within the scope of the study. Amongst the risk factors for ESBL infections studied, gender distribution depicted a predominance of female patients which was similar to the results of the study carried out by Fennell et al. [8], Enoch et al. [6] and RubioPerez et al. [11] but observed to be contradicting the study carried out by Peralta et al. [9], Doernberg and Winston [14] and Schoevaerdts et al. [7], where the result was paradoxical. The range of age groups and median age complied with the studies conducted by Enoch et al. [6] and RubioPerez et al. [11]. Only two patients previously had an ESBL isolated from urine samples before the study period. Advanced age has demonstrated to be an independent risk factor for infection in many studies. In the current study, most of the infected patients comprised geriatrics. It was found that two-third of the patients were elderly patients aged over 60 years, presented a large variety of comorbidities and majority had hospitalization episodes or multiple contacts with the hospital within the previous 12 months. The results obtained were consistent with the results of Schoevaerdts et al. [7]. Majority of patients were admitted for a period of 6–10 days and overall mortality rate during hospitalization was 12 (10.16%). Six out of the 12 patients who died were hospitalized in the ICU at the time of death. Comorbidities were not reported in 14.41% (17) of patients in contrast to the rest who had diabetes mellitus, hypertension, renal failure, coronary artery disease, chronic obstructive pulmonary disease (COPD) and cirrhosis. Diabetes mellitus was the most frequent comorbidity, present in 56.78% of our hospitalized patients. This implies that altered metabolism and associated immune deficiency may have led to higher risk of infection, particularly those related to catheter, wound and bacteremia similar to the result of the study conducted by Rubio-Perez et al. [11], Doernberg and Winston [14] and Schoevaerdts et al. [7]. Ninety patients (76.27%) had vascular/urinary catheterization and 14 patients (11.86%) had endotracheal tube at some point during hospitalization. Foley catheterization is a well-known risk factor for urinary tract infection and is attributed to the unskilled sterilization technique during
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
Chandrasekhar et al.: Antimicrobial susceptibility pattern of ESBL-producing bacteria 7
insertion of the catheter. Therefore, unnecessary catheterization should be avoided in patients with urinary tract infection to prevent emergence of ESBL-producing bacteria in consistence with the result of the study carried out by Rubio-Perez et al. [11], Lee et al. [15] and Mehrgan and Rahbar [16]. Other risk factors for infection by ESBL-producing bacteria were previous hospitalization (38.13%) and previous antibiotic therapy (63.56%). In 25.42% of patients, the antibiotic treatment received included two or more different antibiotics. This may be due to the fact that previous antibiotic therapy, especially if lengthy or inappropriate, allows mutant strains to become dominant leading to consolidation of resistance. The result is consistent with the result of the study conducted by Lee et al. [15] and Wu et al. [17]. ICU admission was another risk factor as evident from the data that 25.42% patients had been hospitalized in the ICU before detection of an ESBL. ICU patients are more susceptible to infection by multi-resistant microorganisms, with multiple risk factors. This result was found to comply with the study results of Villegas et al. [18], RubioPerez et al. [11], Schoevaerdts et al. [7] and Nasa et al. [19]. The proportion of patients who had received one or more courses of antimicrobial therapy was high (63.56%) appeared to be a risk factor for ESBL in line with the study conducted by Lonchel et al. [20], Schoevaerdts et al. [7], Rubio-Perez [11] and Enoch et al. [6]. The antibiotic sensitivity pattern revealed that the maximum sensitivity was seen for meropenem (100.0%), followed by piperacillin-tazobactam (92.4%), cefoperazone-sulbactam (90.7%), amikacin (88.1%) and chloramphenicol (84.7%). A high resistance rate was seen for cefotaxime (100.0%), amoxicillin-clavulanic acid (95.8%), ciprofloxacin (79.7%), co-trimoxazole (65.3%) and doxycycline (56.6%). The study of antimicrobial sensitivity globally demonstrated high resistance rates to quinolones (up to 83% ciprofloxacin resistance) which is somewhat similar to this study result. Amikacin presented a good rate of sensitivity in all species attributed to the nadir in the aminoglycoside use over the past few years due to the nephrotoxic potential. Carbapenems have been the most successful antibiotics against ESBL-producing bacteria because of their β-lactamase stability and continue to be the treatment of choice. This result was consistent with the results of the study carried out by Shanthi and Sekar [21], Dalela [22] and Nasa et al. [19]. The sensitivity pattern of these microorganisms indicates a high degree of resistance acquired by the microorganisms toward the commonly used antimicrobials which has culminated in therapeutic failures and the spread of
resistant organism from infected to non-infected individuals in hospital through the hands of health care providers and via contaminated equipment.
Conclusions The emerging problem of ESBL-producing bacteria has become domain of grave concern in the last few decades. These bacteria have been increasingly reported as causative agents of nosocomial and community-acquired infections worldwide with resistance patterns demonstrating significant variability. The study demonstrated higher prevalence of ESBL infection in contrast to the hospitals in developed countries. The current study had identified the following conditions as risk factors for the development of ESBL-producing microorganisms in the study population: –– Female sex –– Geriatric population is highly vulnerable –– Urinary and respiratory tract infections –– Presence of invasive devices –– Escherichia coli as the causative organism Since there are inter-institutional as well as global variations, similar studies can be utilized in estimating the risk factors which have the potential to augment the growth of ESBL-producing isolates in the specific institutions. The cognizance of institutional resistance patterns can aid physicians in selecting adequate empirical antibiotic regimens, so that antibiotics with high resistance rates are avoided and treatment can be tailored in each patient by considering individual risk factors. Such measures can not only prevent morbidity and mortality but also assist in achieving a better control over hospital infections. An effective infection control program supplemented with an antimicrobial surveillance program can contribute significantly toward limiting the spread of resistance. The current study demonstrated that the level of isolation measures was only 49.15% to the optimum depicting a margin for improvement. Isolation measures included correct use of sterile gloves and aprons, systematic hand decontamination before and after visiting the patients, isolated single rooms and restricted visitors. On evaluation of the resistance pattern, E. coli and Klebsiella showed high resistance against cefotaxime, amoxicillin-clavulanic acid, ciprofloxacin and co-trimoxazole. The antibiotic sensitivity pattern revealed that the maximum sensitivity was seen for meropenem, piperacillin-tazobactam, cefoperazone-sulbactam and amikacin.
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
8 Chandrasekhar et al.: Antimicrobial susceptibility pattern of ESBL-producing bacteria In the wake of the depleted antibiotics currently in the production pipeline, this study emphasizes the need for continuous monitoring of the antimicrobial susceptibility pattern of ESBL pathogens toward the commonly used AMA for the selection of appropriate therapy so as to conserve the presently available resources against the accelerating resistance patterns. Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission. Research funding: None declared. Employment or leadership: None declared. Honorarium: None declared. Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.
References 1. Tripathi KD. Antimicrobial drugs: general considerations. In: Tripathi KD, editor. Essentials of medical pharmacology, 5th ed. New Delhi: Jaypee Publishers, 2003:627–40. 2. Reghunath D. Emerging antibiotic resistance bacteria with special reference to India. J Biosci 2008;33:593–603. 3. Komlafe OO. Antibiotic resistance in bacteria-an emerging public health problem. Malawi Med J 2004;15:63–7. 4. Pathak A, Marothi Y, Kekre V, Mahadik K, Macaden R, Lundborg CS. High prevalence of extended-spectrum β-lactamase-producing pathogens: results of a surveillance study in two hospitals in Ujjain, India. Infect Drug Resist 2012;5:65–73. 5. Thenmozhi S, Sureshkumar BT. Prevalence of extended spectrum beta-lactamase producing gram-negative bacteria in private hospital, Tiruchengode, Tamilnadu, India. Int J Curr Microbiol App Sci 2013;2:280–9. 6. Enoch DA, Brown F, Sismey AW, Mlangeni DA, Curran MD, Karas JA, et al. Epidemiology of extended-spectrum beta-lactamase-producing Enterobacteriaceae in a UK district hospital; an observational study. J Hosp Infect 2012;81:270–7. 7. Schoevaerdts D, Bogaerts P, Grimmelprez A, de Saint-Hubert M, Delaere B, Jamart J, et al. Clinical profiles of patients colonized or infected with extended-spectrum beta-lactamase producing Enterobacteriaceae isolates: a 20 month retrospective study at a Belgian University Hospital. BMC Infect Dis 2011;11:12. 8. Fennell J, Vellinga A, Hanahoe B, Morris D, Boyle F, Higgins F. Increasing prevalence of ESBL production among Irish clinical Enterobacteriaceae from 2004 to 2008: an observational study. BMC Infect Dis 2012;12:116.
9. Peralta G, Lamelo M, Álvarez-García P, Velasco M, Delgado A, Horcajada JP, et al. Impact of empirical treatment in extendedspectrum beta-lactamase-producing Escherichia coli and Klebsiella spp. bacteremia. A multicentric cohort study. BMC Infect Dis 2012;12:245. 10. Sarojamma V, Rmakrishna V. Prevalence of ESBL-producing Klebsiella pneumoniae isolates in tertiary care hospital. ISRN Microbiol 2011;2011:5. 11. Rubio-Perez I, Martin-Perez E, Garcia DD, Calvo ML, Barrera EL. Extended-spectrum beta-lactamase-producing bacteria in a tertiary care hospital in Madrid: epidemiology, risk factors and antimicrobial susceptibility patterns. Emerg Health Threats J 2012;5:1–6. 12. Rivard-Yazigi L, Zahar JR, Le Guillou S, Chalouhi C, Lecuyer H, Bureau C, et al. Risk factors associated with extended-spectrum β-lactamase-producing Enterobacteriaceae carriage at admission in an infant cohort at a tertiary teaching hospital in France. Am J Infect Control 2013;41:844–5. 13. Khan SA, Feroz F, Noor R. Study of extended-spectrum β-lactamase-producing bacteria from urinary tract infections in Bangladesh. Tzu Chi Med J 2013;25:39–42. 14. Doernberg SB, Winston LG. Risk factors for acquisition of extended-spectrum β-lactamase-producing Escherichia coli in an urban county hospital. Am J Infect Control 2012;40:123–7. 15. Lee DS, Lee CB, Lee S-J. Prevalence and risk factors for extended spectrum beta-lactamase-producing uropathogens in patients with urinary tract infection. Korean J Urol 2010;51:492–7. 16. Mehrgan H, Rahbar M. Prevalence of extended-spectrum betalactamase-producing Escherichia coli in a tertiary care hospital in Tehran, Iran. Int J Antimicrob Agents 2008;31:147–51. 17. Wu UI, Yang CS, Chen WC, Chen YC, Chang SC. Risk factors for bloodstream infections due to extended-spectrum beta-lactamase-producing Escherichia coli. J Microbiol Immunol Infect 2010;43:310–6. 18. Villegas MV, Blanco MG, Sifuentes-Osornio J, Rossi F. Increasing prevalence of extended-spectrum-beta-lactamase among gramnegative bacilli in Latin America – 2008 update from the Study for Monitoring Antimicrobial Resistance Trends (SMART). Braz J Infect Dis 2011;15:34–9. 19. Nasa P, Juneja D, Singh O, Dang R, Singh A. An observational study on bloodstream extended-spectrum beta-lactamase infection in critical care unit: incidence, risk factors and its impact on outcome. Eur J Intern Med 2012;23:192–5. 20. Lonchel CM, Meex C, Gangoué-Piéboji J, Boreux R, Assoumou MC, Melin P, et al. Proportion of extended-spectrum β-lactamase-producing Enterobacteriaceae in community setting in Ngaoundere, Cameroon. BMC Infect Dis 2012;12:53. 21. Shanthi M, Sekar U. Extended spectrum beta lactamase producing Escherichia coli and Klebsiella pneumoniae: risk factors for infection and impact of resistance on outcomes. J Assoc Phys India 2010;58(Suppl):41–4. 22. Dalela G. Prevalence of extended-spectrum beta lactamase (ESBL) producers among gram negative bacilli from various clinical isolates in a tertiary care hospital at Jhalawar, Rajasthan, India. J Clin Diagn Res 2012;6:182–7.
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
Dilip Chandrasekhar*, Jaffer Chalilparambil, Sajitha Mukriyan Kallungal, Danisha Pattani, Abin Chandrakumar and Vikas Pokkavayalil
Prevalence, risk factors and antimicrobial susceptibility pattern of extended spectrum β-lactamase-producing bacteria in a tertiary care hospital DOI 10.1515/jbcpp-2015-0020 Received March 3, 2015; accepted November 13, 2015
Abstract Background: The widespread misuse of antibiotics over the past several decades has been regarded as the contributing factor in the development of resistance toward them. Extended spectrum β-lactamases (ESBLs) are enzymes produced by certain bacteria that can make them resistant to certain antibiotics. Early detection of ESBL strains and judicious use of antibiotics and proper implementation of infection control strategies are essential to prevent the spread of this threat in the community. The study aimed at appraising the prevalence, risk factors and antimicrobial susceptibility pattern of ESBL-producing microorganisms. Methods: A prospective observational study was carried out in a tertiary care referral hospital located in Malappuram district of Kerala among inpatients with infection by ESBL-producing bacteria in order to estimate the prevalence, risk factors and their antibiotic susceptibility pattern. Results: Out of the total 1156 patients studied, 118 had confirmed diagnosis on the presence of ESBL-producing microorganisms. Overall, 9.79% of all samples growing Enterobacteriaceae yielded an ESBL producer. Out of the total isolates identified, 66.1% were urinary tract infections, 15.1% were respiratory tract infections, 14.4% were surgical site infections and the remaining constituted *Corresponding author: Dilip Chandrasekhar, Professor and Head, Department of Pharmacy Practice, Al Shifa College of Pharmacy, Poonthavanam, P.O. Perinthalmanna, Kerala-679325, India, E-mail: [email protected] Jaffer Chalilparambil: Department of General Medicine, KIMS Al Shifa Hospital, Perinthalmanna, Kerala, India Sajitha Mukriyan Kallungal, Danisha Pattani, Abin Chandrakumar and Vikas Pokkavayalil: Department of Pharmacy Practice, Al Shifa College of Pharmacy, Poonthavanam, Kizhattur, P.O. Perinthalmanna, Kerala, India
blood stream infections. The highest antimicrobial activity against ESBL-producing isolates was observed for meropenem. Conclusions: High prevalence of ESBL-producing organisms is evident in the study setting implicating the necessity to report the ESBL production along with the routine sensitivity reports supplemented with control measures which can assist a clinician in prescribing appropriate antibiotics. Keywords: antimicrobial susceptibility; prevalence; risk factors.
Introduction Antibiotics are substances produced by microorganisms, which suppress the growth of or kill other microorganisms at very low concentrations [1]. The discovery of antimicrobial agents (AMA) was one of the greatest medical triumphs of the 20th century and has become one of the most commonly prescribed groups of drugs in modern practice. The antibiotic era started in the 1940s and changed the profile of infectious diseases and human demography [2]. Starting with the introduction into the medical practice of the sulfonamides in the 1930s, penicillin and streptomycin in the 1940s, the broad spectrum bacteriostatic antibiotics during the 1950s, followed by bactericidal antibiotics in the 1960s, together with other important synthetic chemicals and highly specific narrow spectrum antibiotics during these years, the AMA revolutionized the treatment of bacterial diseases [3]. Antibiotic resistance is a public health problem. The foundation of modern medicine is built on the availability of effective antibiotics, especially in economically deprived areas of the world where the disease burden due to bacterial infections remains high. Antibiotic resistance is predominantly fueled by antibiotic use. The regular
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
2 Chandrasekhar et al.: Antimicrobial susceptibility pattern of ESBL-producing bacteria introduction of new antibiotic classes over the years has partly masked the problem of increasing resistance. However, this is no longer the case today because the pipeline for newer antibiotics is nearly empty. Therefore, we need to preserve the currently available antibiotics for use by future generations. The World Health Organization and European Commission have recognized the importance of studying the emergence and determination of resistance and the need for control strategies [4]. Infections are defined as community onset if they occur within 48 h of admission in a patient with no hospital admissions in the past 12 months, and health care associated if onset is within 48 h of admission in a patient who, in the preceding year, had (i) been admitted to hospital, (ii) resided in a nursing or residential home, or (iii) required intravenous chemotherapy or hemodialysis. Hospital-onset ESBL infections are defined as occurring more than 48 h after admission. AMA are one of the most commonly prescribed groups of drugs for treating various infectious diseases. The widespread use and sometimes the misuse of antibiotics in all health care facilities over the past several decades have been regarded as the contributing factor in the development of resistance toward them. ESBLs are enzymes produced by certain bacteria that can make them resistant to certain antibiotics. These enzymes produce resistance to a variety of β-lactam antibiotics including extended spectrum penicillins, third generation cephalosporins and monobactams. They often show cross-resistance to many other classes of antibiotics such as fluoroquinolones and amino glycosides by additional mechanisms, thus further limiting treatment options. At present, ESBLs have been increasing as a serious nosocomial and community pathogen having the property of multidrug resistance. With this in mind, the early detection of ESBL strains and judicious use of antibiotics and proper implementation of infection control strategies are essential to prevent the spread of this threat in the community. The following study was aimed at estimating the prevalence, risk factors and antimicrobial susceptibility pattern of ESML-producing microorganisms.
Materials and methods The study was of prospective-observational design and was performed in a tertiary care referral hospital, located in the city of Perinthalmanna in Malappuram District, Kerala. The study was conducted over the duration of 1 year from March 2013 till February 2014. The study protocol was approved by the Institutional Ethical Committee. All patients for whom antimicrobial culture sensitivity was ordered
by the physician were screened to identify patients with ESBL positive culture result. These ESBL patients were included in the study irrespective of their age, sex and department of admission. Patients for whom adequate data were missing from the file and those who denied consent for participation were excluded from the study. The data for the study were obtained through patient interviews and analysis of case sheets. The culture sensitivity reports were obtained from the microbiology lab for each patient. These data were entered into a pre-designed data form. The site of isolation, species of bacteria and antimicrobial resistance pattern were recorded and multiple sites of isolation, if performed, were separately recorded. But successive cultures from the same patient were excluded to avoid duplication. Data on the risk factor for infection with ESBL-producing organisms were collected and assessed. A total of 12 commonly used AMA, which represent the most commonly used antibiotics in our hospital, were selected for the study. The data obtained during the study period were analyzed for estimates of overall prevalence of ESBL-producing microorganisms, stratification on the basis of setting of acquiring infection (community acquired, health care associated and hospital acquired), identification of the risk factors contributing toward the development of resistance, distribution pattern ESBL-producing microorganisms and department-wise distribution and resistance/susceptibility pattern of pathogens toward the commonly used AMA. SPSS 17 for windows version was used to perform statistical analysis. Numerical data are expressed as mean and standard deviation. The frequency distribution of parameters such as gender, department, type of infection and organism isolated was also analyzed. For categorical variables, frequencies and percentages were computed with a χ2-test. For quantitative variables, a paired t-test was used. Results were interpreted with a p-value, which is the probability of accepting the null hypothesis. The significant level was set at 70
51 2 1 10 1 23 26
– – – – 3 6 9
– – – 7 4 1 5
– – – – 3 1 2
BSI, Blood stream infections; RTI, respiratory tract infections; SSI, surgical site infections; UTI, urinary tract infections.
statistical significance using a χ2-test for the null hypothesis that there was no difference between the distribution of male and female in different age groups. The χ2-value obtained was 7.712 (p = 0.173), showing that there was no significant difference and proving the null hypothesis true. The length of hospital stay (in terms of days) ranged from 0 to 5 for 12.7% (n = 15), 6 to 10 for 56.8% (n = 67), 11 to 15 for 22.9% (n = 27) and 16 to 20 for 7.6% (n = 9). The comorbidities in patients with ESBL-producing isolates were diabetes in 56.78% (n = 67), hypertension in 40.68% (n = 48), renal failure in 21.18% (n = 25) and 5.93% (n = 7) each in both cirrhosis and coronary artery disease. The testing of null hypothesis that the distribution of comorbidities was equal in different infections for which ESBL-producing organisms were isolated (Table 4) was performed using a χ2-test which yielded a value of 28.49 (p = 0.019), showing that there was a significant difference in the distribution of comorbidities. A number of patients having prior exposure to antibiotics in each type of infection (Table 5) were tested for the null hypothesis that the number of exposed and unexposed groups was equal in the different types of infection. A χ2-test was used for the hypothesis testing and the value obtained was 10.37 (p = 0.016), which depicts that there is significant difference between the exposed and non-exposed groups. The hypothesis testing was done on the data in Table 6 to estimate the difference between patients who had a history of ICU admission and those who did not, toward developing ESBL-producing organisms in different infection groups. The null hypothesis that there existed no difference was tested by a χ2-test and yielded a value of 23.202 (p = 0.0001), which reveals that there is a highly significant difference between the two groups. Data from Table 7 on the resistance to different classes of antibiotics show high resistance rates to cefotaxime (100.0%), amoxicillin-clavulanic acid (95.8%), ciprofloxacin (79.7%) and co-trimoxazole (65.3%). The data also showcase the high sensitivity of ESBL-producing
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
4 Chandrasekhar et al.: Antimicrobial susceptibility pattern of ESBL-producing bacteria 100%
100%
100%
Female
Male
90% 80%
70.6% 63.4%
70%
57.7%
60% 50%
45.2%
42.3%
40%
54.8% 36.6%
29.4%
30% 20% 10%
0%
0%
0%
Infant
1–10
11–50
51–60
61–70
Above 70
Age distribution, years → Figure 1: Simple bar graph representing subject distribution with respect to gender within each age group.
Table 4: Comparison between the type of infections with respect to comorbidity.
Table 6: Frequency distribution of the previous history of ICU admission.
Comorbidity
Infections
Diabetes
Hypertension Renal failure COPD Cirrhosis Coronary artery disease
UTI 40 59.70% 36 75% 22 88.0% 3 42.86% 5 71.43% 3 60.00%
RTI
12 17.91% 8 16.67% 3 12.0% 4 57.14% 1 14.28% 1 20.00%
SSI
12 17.91% 4 8.33% 0 0% 0 0% 0 0% 0 0%
BSI
3 4.47% 0 0% 0 0% 0 0% 1 14.28% 1 20.00%
Total
67 100.0% 48 100.0% 25 100.0% 7 100.0% 7 100.0% 5 100.0%
BSI, Blood stream infections; COPD, chronic obstructive pulmonary disease; RTI, respiratory tract infections; SSI, surgical site infections; UTI, urinary tract infections.
Table 5: Frequency distribution of prior subject exposure to antibiotic in each type of infection. Infections
UTI RTI SSI BSI Total
Previous exposure to antibiotics No
Yes
65 5 1 3 43
13 13 16 2 75
Total
78 18 17 5 118
BSI, Blood stream infections; RTI, respiratory tract infections; SSI, surgical site infections; UTI, urinary tract infections.
UTI RTI SSI BSI Total
History of admission in ICU Negative 65 13 5 5 88
Total
Positive
13 5 12 0 30
78 18 17 5 118
BSI, Blood stream infections; RTI, respiratory tract infections; SSI, surgical site infections; UTI, urinary tract infections.
isolates toward meropenem (100.0%), followed by piperacillin-tazobactam (92.4%), cefoperazone-sulbactam (90.7%) and amikacin (88.1%). The sensitivity patterns of the three major isolates, namely E. coli, Klebsiella and Enterobacter against various a ntibiotics is represented through Table 8.
Discussion Infections caused by ESBL-producing bacteria have become a serious concern worldwide, indicating that continuous monitoring systems and effective infection control measures are quintessential. Their presence supplemented with the potential for plasmid-mediated carbapenem resistance can catapult significant therapeutic dilemma in the future. β-Lactam antibiotics account for approximately 50% of global antibiotic consumption, and this heavy usage has accelerated the resistance rates.
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
Chandrasekhar et al.: Antimicrobial susceptibility pattern of ESBL-producing bacteria 5 Table 7: Resistance or susceptibility pattern of microorganisms. Antibiotic
Resistant Frequency
Meropenem Cefoperazone-sulbactam Piperacillin-tazobactam Amikacin Amoxicillin-clavulanic acid Cefotaxime Ciprofloxacin Co-trimoxazole Gentamicin Chloramphenicol Doxycycline Tobramycin
Percentage
0 11 9 14 113 118 94 77 50 18 68 50
0% 9.3% 7.6% 11.9% 95.8% 100.0% 79.7% 65.3% 42.4% 15.3% 57.6% 42.4%
Sensitive Frequency
Percentage
118 107 109 104 5 0 24 41 68 100 50 68
100.0% 90.7% 92.4% 88.1% 4.2% 0% 20.3% 34.7% 57.6% 84.7% 42.4% 57.6%
Table 8: Sensitivity pattern of different microorganisms isolated in each antibiotic. Antibiotic
Sensitivity E. coli Frequency
Meropenem Cefoperazone-sulbactam Piperacillin-tazobactam Amikacin Amoxicillin-clavulanic acid Cefotaxime Ciprofloxacin Co-trimoxazole Gentamicin Chloramphenicol Doxycycline Tobramycin
67 63 63 65 4 0 8 22 42 62 26 42
Klebsiella
Percentage
100.0% 92.6% 92.6% 95.59% 5.82% 0% 11.76% 32.36% 61.76% 91.18% 38.23% 61.76%
Enhanced infection control coupled with antibiotic stewardship programs can play a pivotal role in limiting the spread of ESBL-producing organisms. In addition, infection with ESBL-producing bacteria raises mortality leading to prolonged hospital stays supplemented with increased relative treatment costs. Therefore, it is crucial to assess the risk factors for the emergence of ESBL-producing bacteria, and to establish practices which barricade against such resistance. This study delineates the microbiological spectrum of ESBL-producing Enterobacteriaceae, their antimicrobial resistance patterns and the clinical characteristics of patients associated with these infections in a tertiary care teaching hospital. The pattern of resistance can vary internationally, and even locally, between the institutions. Institution-specific surveillance of ESBL prevalence and susceptibility of these pathogens to commonly used antibiotics can catalyze to
Frequency
39 34 35 33 0 0 15 13 22 31 19 20
Enterobacter
Percentage
100.0% 87.17% 89.74% 84.61% 0% 0% 38.46% 33.33% 56.41% 79.48% 48.71% 51.28%
Frequency
10 9 9 5 01 0 1 3 4 6 4 5
Percentage
100.0% 90.0% 90.0% 50.0% 10.0% 0% 10.0% 30.0% 40.0% 60.0% 40.0% 50.0%
enhance patient outcome and preserve the efficacy of the available antibiotic agents. During the study duration spanning one year, a total of 118 hospitalized patients presented non-duplicate clinical isolates positive for ESBL-producing bacteria. A total of 1156 blood, urine, wound and sputum samples were processed during the time frame. Overall, 9.37% of all samples growing Enterobacteriaceae yielded an ESBL producer. This prevalence rate was relatively lower in comparison to the study conducted by Thenmozhi and Sureshkumar [5] and higher than those reported in different studies carried out by Enoch et al. [6] and Schoevaerdts et al. [7]. Reasons for such high rates of resistance may be lack of standard antibiotic guidelines for the treatment of microbiological infections, poor drug quality, increased transmittance rate of infection through hospitalized patients, bystanders or staff, unscientific allocation of infective patients
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
6 Chandrasekhar et al.: Antimicrobial susceptibility pattern of ESBL-producing bacteria and antibiotic abuse due to the easy availability of antibiotics without prescriptions. Onset of infection caused by the ESBL producer was categorized as hospital, community and health care associated in 31 (26.27%), 41 (34.75%) and 46 (38.98%) patients, respectively. Identical studies by Enoch et al. [6] revealed that majority of infections come under health care-associated [67 (54.03%)], followed by community- [31 (25.0%)] and hospital-acquired [26 (20.97%)] infections. The most common site of isolation was urine, followed by respiratory tract. This may be due to the fact that urinary tract infections are the most frequent infections worldwide among the hospitalized patients, and Enterobacteriaceae are generally the causative agents. The four documented infections were urinary tract infection 78 (66.1%), respiratory tract infection 18 (15.2%), surgical site infection 17 (144%) and blood stream infection 5 (4.2%). The predominance of urine samples is consistent with the results of the study carried out by Fennell et al. [8], Peralta et al. [9] and Schoevaerdts et al. [7]. However, there were observable differences from the results of the study carried out by Sarojamma et al. [10], where a greater proportion of ESBL was reported from blood, followed by stool, sputum, urine and pus samples. The departments with the highest number of positive ESBL-producing isolates were general medicine 48 (40.70%) and nephrology 21 (17.80%), as they had higher number of in-patients during the study period. Urinary tract and respiratory tract infections were the two major diagnostic categories and constituted the most frequent types of infection among elderly patients admitted in general medicine departments. This result obtained is consistent with the result of the study carried out by Rubio-Perez et al. [11], but different from the study of Schoevaerdts et al. [7], in which majority of the patients were admitted to the surgery department. The most frequently isolated pathogen was E. coli 68 (66.1%), followed by Klebsiella 39 (33.05%), Enterobacter 10 (8.47%) and Pseudomonas 1 (0.85%). This result obtained was consistent with the result of the study carried out by Fennell et al. [8], Rubio-Perez et al. [11], Enoch et al. [6] and Rivard-Yazigi et al. [12]. In case of urinary tract infection out of the 78 cases, E. coli constituted 51 (65.38%) of the urinary tract infections isolates, followed by Klebsiella 22 (28.20%) and Enterobacter 5 (6.41%). Escherichia coli was more frequently found in association with urinary tract infection; this was in line with the result of the study carried out by Schoevaerdts et al. [7] and Khan et al. [13]. In the current study, the presence of ESBL-producing E. coli amongst the urine specimens is of grave concern, since E. coli is the main causative agent of urinary tract infections, and
consequently, there is widespread use of AMA due to such infections. In respiratory tract infection, Klebsiella (n = 12, 66.67%) was the most commonly isolated organism, followed by E. coli (n = 5, 27.77%) and Enterobacter (n = 1, 5.5%). Out of the 17 surgical site infections studied, E. coli was predominant isolate (n = 7, 41.17%), followed by Klebsiella (n = 5, 29.41%), Enterobacter (n = 4, 23.52%) and Pseudomonas (n = 1, 5.88%). Escherichia coli was the organism responsible for all the blood stream infections which came within the scope of the study. Amongst the risk factors for ESBL infections studied, gender distribution depicted a predominance of female patients which was similar to the results of the study carried out by Fennell et al. [8], Enoch et al. [6] and RubioPerez et al. [11] but observed to be contradicting the study carried out by Peralta et al. [9], Doernberg and Winston [14] and Schoevaerdts et al. [7], where the result was paradoxical. The range of age groups and median age complied with the studies conducted by Enoch et al. [6] and RubioPerez et al. [11]. Only two patients previously had an ESBL isolated from urine samples before the study period. Advanced age has demonstrated to be an independent risk factor for infection in many studies. In the current study, most of the infected patients comprised geriatrics. It was found that two-third of the patients were elderly patients aged over 60 years, presented a large variety of comorbidities and majority had hospitalization episodes or multiple contacts with the hospital within the previous 12 months. The results obtained were consistent with the results of Schoevaerdts et al. [7]. Majority of patients were admitted for a period of 6–10 days and overall mortality rate during hospitalization was 12 (10.16%). Six out of the 12 patients who died were hospitalized in the ICU at the time of death. Comorbidities were not reported in 14.41% (17) of patients in contrast to the rest who had diabetes mellitus, hypertension, renal failure, coronary artery disease, chronic obstructive pulmonary disease (COPD) and cirrhosis. Diabetes mellitus was the most frequent comorbidity, present in 56.78% of our hospitalized patients. This implies that altered metabolism and associated immune deficiency may have led to higher risk of infection, particularly those related to catheter, wound and bacteremia similar to the result of the study conducted by Rubio-Perez et al. [11], Doernberg and Winston [14] and Schoevaerdts et al. [7]. Ninety patients (76.27%) had vascular/urinary catheterization and 14 patients (11.86%) had endotracheal tube at some point during hospitalization. Foley catheterization is a well-known risk factor for urinary tract infection and is attributed to the unskilled sterilization technique during
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
Chandrasekhar et al.: Antimicrobial susceptibility pattern of ESBL-producing bacteria 7
insertion of the catheter. Therefore, unnecessary catheterization should be avoided in patients with urinary tract infection to prevent emergence of ESBL-producing bacteria in consistence with the result of the study carried out by Rubio-Perez et al. [11], Lee et al. [15] and Mehrgan and Rahbar [16]. Other risk factors for infection by ESBL-producing bacteria were previous hospitalization (38.13%) and previous antibiotic therapy (63.56%). In 25.42% of patients, the antibiotic treatment received included two or more different antibiotics. This may be due to the fact that previous antibiotic therapy, especially if lengthy or inappropriate, allows mutant strains to become dominant leading to consolidation of resistance. The result is consistent with the result of the study conducted by Lee et al. [15] and Wu et al. [17]. ICU admission was another risk factor as evident from the data that 25.42% patients had been hospitalized in the ICU before detection of an ESBL. ICU patients are more susceptible to infection by multi-resistant microorganisms, with multiple risk factors. This result was found to comply with the study results of Villegas et al. [18], RubioPerez et al. [11], Schoevaerdts et al. [7] and Nasa et al. [19]. The proportion of patients who had received one or more courses of antimicrobial therapy was high (63.56%) appeared to be a risk factor for ESBL in line with the study conducted by Lonchel et al. [20], Schoevaerdts et al. [7], Rubio-Perez [11] and Enoch et al. [6]. The antibiotic sensitivity pattern revealed that the maximum sensitivity was seen for meropenem (100.0%), followed by piperacillin-tazobactam (92.4%), cefoperazone-sulbactam (90.7%), amikacin (88.1%) and chloramphenicol (84.7%). A high resistance rate was seen for cefotaxime (100.0%), amoxicillin-clavulanic acid (95.8%), ciprofloxacin (79.7%), co-trimoxazole (65.3%) and doxycycline (56.6%). The study of antimicrobial sensitivity globally demonstrated high resistance rates to quinolones (up to 83% ciprofloxacin resistance) which is somewhat similar to this study result. Amikacin presented a good rate of sensitivity in all species attributed to the nadir in the aminoglycoside use over the past few years due to the nephrotoxic potential. Carbapenems have been the most successful antibiotics against ESBL-producing bacteria because of their β-lactamase stability and continue to be the treatment of choice. This result was consistent with the results of the study carried out by Shanthi and Sekar [21], Dalela [22] and Nasa et al. [19]. The sensitivity pattern of these microorganisms indicates a high degree of resistance acquired by the microorganisms toward the commonly used antimicrobials which has culminated in therapeutic failures and the spread of
resistant organism from infected to non-infected individuals in hospital through the hands of health care providers and via contaminated equipment.
Conclusions The emerging problem of ESBL-producing bacteria has become domain of grave concern in the last few decades. These bacteria have been increasingly reported as causative agents of nosocomial and community-acquired infections worldwide with resistance patterns demonstrating significant variability. The study demonstrated higher prevalence of ESBL infection in contrast to the hospitals in developed countries. The current study had identified the following conditions as risk factors for the development of ESBL-producing microorganisms in the study population: –– Female sex –– Geriatric population is highly vulnerable –– Urinary and respiratory tract infections –– Presence of invasive devices –– Escherichia coli as the causative organism Since there are inter-institutional as well as global variations, similar studies can be utilized in estimating the risk factors which have the potential to augment the growth of ESBL-producing isolates in the specific institutions. The cognizance of institutional resistance patterns can aid physicians in selecting adequate empirical antibiotic regimens, so that antibiotics with high resistance rates are avoided and treatment can be tailored in each patient by considering individual risk factors. Such measures can not only prevent morbidity and mortality but also assist in achieving a better control over hospital infections. An effective infection control program supplemented with an antimicrobial surveillance program can contribute significantly toward limiting the spread of resistance. The current study demonstrated that the level of isolation measures was only 49.15% to the optimum depicting a margin for improvement. Isolation measures included correct use of sterile gloves and aprons, systematic hand decontamination before and after visiting the patients, isolated single rooms and restricted visitors. On evaluation of the resistance pattern, E. coli and Klebsiella showed high resistance against cefotaxime, amoxicillin-clavulanic acid, ciprofloxacin and co-trimoxazole. The antibiotic sensitivity pattern revealed that the maximum sensitivity was seen for meropenem, piperacillin-tazobactam, cefoperazone-sulbactam and amikacin.
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
8 Chandrasekhar et al.: Antimicrobial susceptibility pattern of ESBL-producing bacteria In the wake of the depleted antibiotics currently in the production pipeline, this study emphasizes the need for continuous monitoring of the antimicrobial susceptibility pattern of ESBL pathogens toward the commonly used AMA for the selection of appropriate therapy so as to conserve the presently available resources against the accelerating resistance patterns. Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission. Research funding: None declared. Employment or leadership: None declared. Honorarium: None declared. Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.
References 1. Tripathi KD. Antimicrobial drugs: general considerations. In: Tripathi KD, editor. Essentials of medical pharmacology, 5th ed. New Delhi: Jaypee Publishers, 2003:627–40. 2. Reghunath D. Emerging antibiotic resistance bacteria with special reference to India. J Biosci 2008;33:593–603. 3. Komlafe OO. Antibiotic resistance in bacteria-an emerging public health problem. Malawi Med J 2004;15:63–7. 4. Pathak A, Marothi Y, Kekre V, Mahadik K, Macaden R, Lundborg CS. High prevalence of extended-spectrum β-lactamase-producing pathogens: results of a surveillance study in two hospitals in Ujjain, India. Infect Drug Resist 2012;5:65–73. 5. Thenmozhi S, Sureshkumar BT. Prevalence of extended spectrum beta-lactamase producing gram-negative bacteria in private hospital, Tiruchengode, Tamilnadu, India. Int J Curr Microbiol App Sci 2013;2:280–9. 6. Enoch DA, Brown F, Sismey AW, Mlangeni DA, Curran MD, Karas JA, et al. Epidemiology of extended-spectrum beta-lactamase-producing Enterobacteriaceae in a UK district hospital; an observational study. J Hosp Infect 2012;81:270–7. 7. Schoevaerdts D, Bogaerts P, Grimmelprez A, de Saint-Hubert M, Delaere B, Jamart J, et al. Clinical profiles of patients colonized or infected with extended-spectrum beta-lactamase producing Enterobacteriaceae isolates: a 20 month retrospective study at a Belgian University Hospital. BMC Infect Dis 2011;11:12. 8. Fennell J, Vellinga A, Hanahoe B, Morris D, Boyle F, Higgins F. Increasing prevalence of ESBL production among Irish clinical Enterobacteriaceae from 2004 to 2008: an observational study. BMC Infect Dis 2012;12:116.
9. Peralta G, Lamelo M, Álvarez-García P, Velasco M, Delgado A, Horcajada JP, et al. Impact of empirical treatment in extendedspectrum beta-lactamase-producing Escherichia coli and Klebsiella spp. bacteremia. A multicentric cohort study. BMC Infect Dis 2012;12:245. 10. Sarojamma V, Rmakrishna V. Prevalence of ESBL-producing Klebsiella pneumoniae isolates in tertiary care hospital. ISRN Microbiol 2011;2011:5. 11. Rubio-Perez I, Martin-Perez E, Garcia DD, Calvo ML, Barrera EL. Extended-spectrum beta-lactamase-producing bacteria in a tertiary care hospital in Madrid: epidemiology, risk factors and antimicrobial susceptibility patterns. Emerg Health Threats J 2012;5:1–6. 12. Rivard-Yazigi L, Zahar JR, Le Guillou S, Chalouhi C, Lecuyer H, Bureau C, et al. Risk factors associated with extended-spectrum β-lactamase-producing Enterobacteriaceae carriage at admission in an infant cohort at a tertiary teaching hospital in France. Am J Infect Control 2013;41:844–5. 13. Khan SA, Feroz F, Noor R. Study of extended-spectrum β-lactamase-producing bacteria from urinary tract infections in Bangladesh. Tzu Chi Med J 2013;25:39–42. 14. Doernberg SB, Winston LG. Risk factors for acquisition of extended-spectrum β-lactamase-producing Escherichia coli in an urban county hospital. Am J Infect Control 2012;40:123–7. 15. Lee DS, Lee CB, Lee S-J. Prevalence and risk factors for extended spectrum beta-lactamase-producing uropathogens in patients with urinary tract infection. Korean J Urol 2010;51:492–7. 16. Mehrgan H, Rahbar M. Prevalence of extended-spectrum betalactamase-producing Escherichia coli in a tertiary care hospital in Tehran, Iran. Int J Antimicrob Agents 2008;31:147–51. 17. Wu UI, Yang CS, Chen WC, Chen YC, Chang SC. Risk factors for bloodstream infections due to extended-spectrum beta-lactamase-producing Escherichia coli. J Microbiol Immunol Infect 2010;43:310–6. 18. Villegas MV, Blanco MG, Sifuentes-Osornio J, Rossi F. Increasing prevalence of extended-spectrum-beta-lactamase among gramnegative bacilli in Latin America – 2008 update from the Study for Monitoring Antimicrobial Resistance Trends (SMART). Braz J Infect Dis 2011;15:34–9. 19. Nasa P, Juneja D, Singh O, Dang R, Singh A. An observational study on bloodstream extended-spectrum beta-lactamase infection in critical care unit: incidence, risk factors and its impact on outcome. Eur J Intern Med 2012;23:192–5. 20. Lonchel CM, Meex C, Gangoué-Piéboji J, Boreux R, Assoumou MC, Melin P, et al. Proportion of extended-spectrum β-lactamase-producing Enterobacteriaceae in community setting in Ngaoundere, Cameroon. BMC Infect Dis 2012;12:53. 21. Shanthi M, Sekar U. Extended spectrum beta lactamase producing Escherichia coli and Klebsiella pneumoniae: risk factors for infection and impact of resistance on outcomes. J Assoc Phys India 2010;58(Suppl):41–4. 22. Dalela G. Prevalence of extended-spectrum beta lactamase (ESBL) producers among gram negative bacilli from various clinical isolates in a tertiary care hospital at Jhalawar, Rajasthan, India. J Clin Diagn Res 2012;6:182–7.
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/27/16 6:42 PM
