Indian Journal of Medical Microbiology, (2015) 33(2): 248-254
1
Original Article
Incidence, risk factors, microbiology of venous catheter associated bloodstream infections - A prospective study from a tertiary care hospital *M Kaur, V Gupta, S Gombar, J Chander, T Sahoo
Abstract Purpose: Central venous catheters (CVCs) though indispensable in current medical and intensive care treatment, also puts patients at risk of catheter related infection (CRI) resulting in increased morbidity and mortality. We analysed the incidence, risk factors, bacteriological profile and antimicrobial susceptibility pattern of the isolates in central venous catheter associated bloodstream infection (CVC‑BSI) in the intensive care unit (ICU) patients and studied the formation of biofilm in CVCs. Materials and Methods: The following case control study included 115 patients with CVC in situ. Quantitative blood cultures (QBC) and catheter tip cultures were performed for the diagnoses. Direct catheter staining was done for an early diagnosis by acridine orange (AO) and Gram staining methods. Biofilm production in catheters was detected by ‘tissue culture plate’ (TCP) method. The results were analysed using the computer‑based program statistical package for the social sciences (SPSS). Results: In 25/115 patients, definite diagnosis of CVC‑BSI was made. The mean age was 48.44 ± 17.34 years (cases) vs 40.10 ± 18.24 years (controls) and the mean duration of catheterisation was 25.72 ± 8.73 days (cases) vs 11.89 ± 6.38 days (controls). Local signs of infection (erythema, tenderness and oozing) were found more significantly in CVC‑BSI cases. The AO staining was more sensitive and Gram staining of catheters showed higher specificity. Staphylococcus aureus followed by Pseudomonas aeruginosa and non‑albicans Candida were common CVC‑BSI pathogens. Multidrug‑resistant (MDR) strains were isolated in bacterial agents of CVC‑BSI. Non‑albicans Candida and Enterococcus faecalis showed strong biofilm production. Conclusion: The incidence of CVC‑BSI was 21.73% and the rate was 14.59 per 1000 catheter days. Prolonged ICU stay and longer catheterisation were major risk factors. S. aureus was isolated most commonly in CVC‑BSI cases. The menace of multidrug resistance and biofilm formation in CVCs is associated with CVC‑BSI. Key words: Antimicrobial susceptibility, biofilm formation, CVC‑BSI, multidrug resistance, S. aureus
Introduction Central venous access plays an important role in the management of critically ill patients and also puts patients at risk of various iatrogenic complications including central venous catheter associated bloodstream infection (CVC‑BSI). The rate of CVC‑BSI across Indian hospitals range from 4.01/1000 catheter days to 9.26/1000 catheter days citing the need for effective infection control programmes including surveillance and antibiotic policies.[1‑3] *Corresponding author (email: ) Department of Microbiology (MK, VG, JC, TS, SG), Government Medical College Hospital, Chandigarh, India Received: 12‑03‑2014 Accepted: 29-09-2014 Access this article online Quick Response Code:
Gram‑positive cocci are responsible for at least two‑thirds of the infections followed by Gram‑negative bacilli, which are responsible for a higher proportion of catheter related infections (CRIs) in intensive care unit (ICU) than in non‑ICU patients.[4] Biofilm formation in catheters has not only been implicated as an important factor involved in device related infection but also confers resistance to antimicrobial treatment.[5] The preventive strategies like the use of antimicrobial impregnated catheters and foremost the aseptic catheter insertion technique using maximal sterile barrier (MSB) precautions have been shown to reduce the rate of CVC‑BSI.[6] Due to the scarcity of CVC‑BSI data from our region of the country, we planned to conduct this study in our ICU of the tertiary care government hospital determining the incidence, risk factors for CVC‑BSI, microbiological profile, antimicrobial susceptibility and biofilm formation by the CVC‑BSI isolates.
Website: www.ijmm.org
Materials and Methods
DOI: 10.4103/0255-0857.153572
The prospective observational case‑control study was conducted on 115 adult ICU patients from October 2010 to September 2011 after due ethical approval of the hospital ethics committee. The patients with in situ central venous
April-June 2015
249
Kaur, et al.: CVC-BSI - A prospective study
catheters (CVCs) (>3 days of insertion) and sterile blood culture immediate after catheterisation were enrolled in the study after taking informed consent. Patients who got CVCs inserted outside our hospital and less than 12 years of age were excluded from the study. Cases were defined as the patients who were diagnosed to have CVC‑BSI while the control population did not suffer from CVC‑BSI.
CVC and peripheral vein yielding the same organism in the presence of either significant catheter‑tip colonisation with ≥103 CFU of the same organism isolated from the blood cultures, or simultaneous quantitative blood cultures (QBCs) in which the number of CFUs isolated from the blood drawn through the CVC was at least 5‑fold greater than the number isolated from blood drawn percutaneously.[8]
The patient’s clinical data and the CVC related information were collected and analysed [Table 1]. The surveillance for CVC‑BSI and catheter colonisation was conducted among all eligible ICU patients based on following definitions:
Patients presenting with signs of sepsis were investigated by performing QBC from the central and peripheral vein. The QBCs were performed using pour plate method due to lack of automated blood culture techniques at our institute. The significant colony count in unpaired central line blood culture was ≥ 100 CFU while a central‑to‑peripheral blood culture colony count ratio of 5:1 was considered indicative of CVC‑BSI.[9,10]
Catheter colonisation ‑ Growth of organisms from a catheter segment by either semi‑quantitative [≥15 colony forming unit (CFU)] or quantitative culture [≥103 CFU] from a proximal or distal catheter segment in the absence of accompanying clinical symptoms.[7] The central venous catheter associated blood stream infection ‑ Positive simultaneous blood cultures from Table 1: Demographic and clinical characteristics Characteristics Cases; Controls; P value1 n=25 (%) n=90 (%) 2 Age (mean±SD ) 48.44±17.34 40.10±18.24 0.029 Gender Male 12 (48) 60 (66.7) 0.088 Female 13 (52) 30 (33.3) Underlying co morbidity Hypertension 6 (24) 19 (21.1) 0.752 Diabetes mellitus 5 (20) 14 (15.6) 0.761 Malignancy 3 (12) 11 (12.2) 1 COPD3 3 (12) 5 (5.6) 0.368 Renal failure 0 (0) 4 (4.4) 0.575 Bronchial Asthma 1 (4) 3 (3.3) 1 None 7 (28) 59 (65.6) 0.0001 Outcome Death 8 (32) 36 (40) 0.467 Survival 17 (68) 54 (60) Catheter insertion site Subclavian 17 (68) 50 (55.6) 0.493 Jugular 8 (32) 40 (44.4) Femoral 0 (0) 1 (1.1) Duration of 25.72±8.73 11.89±6.37
1
Original Article
Incidence, risk factors, microbiology of venous catheter associated bloodstream infections - A prospective study from a tertiary care hospital *M Kaur, V Gupta, S Gombar, J Chander, T Sahoo
Abstract Purpose: Central venous catheters (CVCs) though indispensable in current medical and intensive care treatment, also puts patients at risk of catheter related infection (CRI) resulting in increased morbidity and mortality. We analysed the incidence, risk factors, bacteriological profile and antimicrobial susceptibility pattern of the isolates in central venous catheter associated bloodstream infection (CVC‑BSI) in the intensive care unit (ICU) patients and studied the formation of biofilm in CVCs. Materials and Methods: The following case control study included 115 patients with CVC in situ. Quantitative blood cultures (QBC) and catheter tip cultures were performed for the diagnoses. Direct catheter staining was done for an early diagnosis by acridine orange (AO) and Gram staining methods. Biofilm production in catheters was detected by ‘tissue culture plate’ (TCP) method. The results were analysed using the computer‑based program statistical package for the social sciences (SPSS). Results: In 25/115 patients, definite diagnosis of CVC‑BSI was made. The mean age was 48.44 ± 17.34 years (cases) vs 40.10 ± 18.24 years (controls) and the mean duration of catheterisation was 25.72 ± 8.73 days (cases) vs 11.89 ± 6.38 days (controls). Local signs of infection (erythema, tenderness and oozing) were found more significantly in CVC‑BSI cases. The AO staining was more sensitive and Gram staining of catheters showed higher specificity. Staphylococcus aureus followed by Pseudomonas aeruginosa and non‑albicans Candida were common CVC‑BSI pathogens. Multidrug‑resistant (MDR) strains were isolated in bacterial agents of CVC‑BSI. Non‑albicans Candida and Enterococcus faecalis showed strong biofilm production. Conclusion: The incidence of CVC‑BSI was 21.73% and the rate was 14.59 per 1000 catheter days. Prolonged ICU stay and longer catheterisation were major risk factors. S. aureus was isolated most commonly in CVC‑BSI cases. The menace of multidrug resistance and biofilm formation in CVCs is associated with CVC‑BSI. Key words: Antimicrobial susceptibility, biofilm formation, CVC‑BSI, multidrug resistance, S. aureus
Introduction Central venous access plays an important role in the management of critically ill patients and also puts patients at risk of various iatrogenic complications including central venous catheter associated bloodstream infection (CVC‑BSI). The rate of CVC‑BSI across Indian hospitals range from 4.01/1000 catheter days to 9.26/1000 catheter days citing the need for effective infection control programmes including surveillance and antibiotic policies.[1‑3] *Corresponding author (email: ) Department of Microbiology (MK, VG, JC, TS, SG), Government Medical College Hospital, Chandigarh, India Received: 12‑03‑2014 Accepted: 29-09-2014 Access this article online Quick Response Code:
Gram‑positive cocci are responsible for at least two‑thirds of the infections followed by Gram‑negative bacilli, which are responsible for a higher proportion of catheter related infections (CRIs) in intensive care unit (ICU) than in non‑ICU patients.[4] Biofilm formation in catheters has not only been implicated as an important factor involved in device related infection but also confers resistance to antimicrobial treatment.[5] The preventive strategies like the use of antimicrobial impregnated catheters and foremost the aseptic catheter insertion technique using maximal sterile barrier (MSB) precautions have been shown to reduce the rate of CVC‑BSI.[6] Due to the scarcity of CVC‑BSI data from our region of the country, we planned to conduct this study in our ICU of the tertiary care government hospital determining the incidence, risk factors for CVC‑BSI, microbiological profile, antimicrobial susceptibility and biofilm formation by the CVC‑BSI isolates.
Website: www.ijmm.org
Materials and Methods
DOI: 10.4103/0255-0857.153572
The prospective observational case‑control study was conducted on 115 adult ICU patients from October 2010 to September 2011 after due ethical approval of the hospital ethics committee. The patients with in situ central venous
April-June 2015
249
Kaur, et al.: CVC-BSI - A prospective study
catheters (CVCs) (>3 days of insertion) and sterile blood culture immediate after catheterisation were enrolled in the study after taking informed consent. Patients who got CVCs inserted outside our hospital and less than 12 years of age were excluded from the study. Cases were defined as the patients who were diagnosed to have CVC‑BSI while the control population did not suffer from CVC‑BSI.
CVC and peripheral vein yielding the same organism in the presence of either significant catheter‑tip colonisation with ≥103 CFU of the same organism isolated from the blood cultures, or simultaneous quantitative blood cultures (QBCs) in which the number of CFUs isolated from the blood drawn through the CVC was at least 5‑fold greater than the number isolated from blood drawn percutaneously.[8]
The patient’s clinical data and the CVC related information were collected and analysed [Table 1]. The surveillance for CVC‑BSI and catheter colonisation was conducted among all eligible ICU patients based on following definitions:
Patients presenting with signs of sepsis were investigated by performing QBC from the central and peripheral vein. The QBCs were performed using pour plate method due to lack of automated blood culture techniques at our institute. The significant colony count in unpaired central line blood culture was ≥ 100 CFU while a central‑to‑peripheral blood culture colony count ratio of 5:1 was considered indicative of CVC‑BSI.[9,10]
Catheter colonisation ‑ Growth of organisms from a catheter segment by either semi‑quantitative [≥15 colony forming unit (CFU)] or quantitative culture [≥103 CFU] from a proximal or distal catheter segment in the absence of accompanying clinical symptoms.[7] The central venous catheter associated blood stream infection ‑ Positive simultaneous blood cultures from Table 1: Demographic and clinical characteristics Characteristics Cases; Controls; P value1 n=25 (%) n=90 (%) 2 Age (mean±SD ) 48.44±17.34 40.10±18.24 0.029 Gender Male 12 (48) 60 (66.7) 0.088 Female 13 (52) 30 (33.3) Underlying co morbidity Hypertension 6 (24) 19 (21.1) 0.752 Diabetes mellitus 5 (20) 14 (15.6) 0.761 Malignancy 3 (12) 11 (12.2) 1 COPD3 3 (12) 5 (5.6) 0.368 Renal failure 0 (0) 4 (4.4) 0.575 Bronchial Asthma 1 (4) 3 (3.3) 1 None 7 (28) 59 (65.6) 0.0001 Outcome Death 8 (32) 36 (40) 0.467 Survival 17 (68) 54 (60) Catheter insertion site Subclavian 17 (68) 50 (55.6) 0.493 Jugular 8 (32) 40 (44.4) Femoral 0 (0) 1 (1.1) Duration of 25.72±8.73 11.89±6.37
