Journal of Chemotherapy
ISSN: 1120-009X (Print) 1973-9478 (Online) Journal homepage: http://www.tandfonline.com/loi/yjoc20
Prevalence of CTX-M-8 and CTX-M-15 type extended-spectrum beta-lactamases between Klebsiella pneumoniae spp. isolated from Zahedan, Southeast Iran Shahram Shahraki-Zahedani, Mehdi Moghadampour, Mohammad Bokaeian & Alireza Ansari-Moghaddam To cite this article: Shahram Shahraki-Zahedani, Mehdi Moghadampour, Mohammad Bokaeian & Alireza Ansari-Moghaddam (2016) Prevalence of CTX-M-8 and CTX-M-15 type extended-spectrum beta-lactamases between Klebsiella pneumoniae spp. isolated from Zahedan, Southeast Iran, Journal of Chemotherapy, 28:4, 343-345, DOI: 10.1179/1973947815Y.0000000008 To link to this article: http://dx.doi.org/10.1179/1973947815Y.0000000008
Published online: 27 Jul 2016.
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Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=yjoc20 Download by: [Weill Cornell Medical College]
Date: 27 July 2016, At: 01:49
Brief Communication
Prevalence of CTX-M-8 and CTX-M-15 type extended-spectrum beta-lactamases between Klebsiella pneumoniae spp. isolated from Zahedan, Southeast Iran Shahram Shahraki-Zahedani1,2, Mehdi Moghadampour2, Mohammad Bokaeian3, Alireza Ansari-Moghaddam4 Infectious Diseases and Tropical Medicine Research Center, Zahedan University of Medical Sciences, Zahedan, Iran, 2Department of Microbiology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran, 3Department of Laboratory Sciences, School of Paramedical Sciences, Zahedan University of Medical Sciences, Zahedan, Iran, 4Health Promotion Research Center, Zahedan University of Medical Sciences, Zahedan, Iran
Downloaded by [Weill Cornell Medical College] at 01:49 27 July 2016
1
Extended-spectrum beta-lactamases (ESBLs) are bacterial plasmid-encoded enzymes that cause bacterial resistance against the penicillins, the first-, second- and third-generation cephalosporins, as well as aztreonam by hydrolysing these antibiotics. ESBLs are inhibited by beta-lactamase inhibitors such as clavulanic acid.1 On the base of Ambler et al. classification, beta-lactamase enzymes are divided into four classes designated as classes A–D.2 Most of the ESBLs are classified as class A.3 Class A ESBLs form a heterogeneous molecular group and are included of three major groups: the TEM, SHV and CTX-M types.4 The CTX-M type ESBLs are developed from TEM and SHV ESBLs and are the commonest group of ESBLs that according to their amino acid sequence similarities are divided into five subgroups including CTX-M-I, CTXM-II, CTX-M-III, CTX-M-IV and CTX-M-V.1,3,4 During the last decade, there has been a shift in the detected ESBL enzymes from the classic TEM and SHV enzyme families, which were mainly detected in the 1980s and 1990s, to the CTX-M family, which was dominated in the last decade.5 The prevalence of ESBLs among clinical isolates of Enterobacteriaceae and especially Klebsiella pneumoniae strains has become a worldwide problem.6 Moreover, several studies have reported high prevalence of these enzymes (CTX-M type ESBLs) in IRAN.7,8 The aim of this sectional-descriptive study was to determine the prevalence of ESBLs-producing isolates of K. pneumoniae at three major hospitals of Zahedan and to characterize the blaCTX-M gene by polymerase chain reaction (PCR) and DNA sequencing. To the best of our knowledge, this Correspondence to: Mehdi Moghadampour, Department of Microbiology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran. Email [email protected]
© 2016 Edizioni Scientifiche per l'Informazione su Farmaci e Terapia DOI 10.1179/1973947815Y.0000000008
is the first report from a southeastern region of Iran examining the presence of K. pneumoniae isolates producing CTX-M genes. One hundred sixty three unrepeated clinical isolates of K. pneumoniae were isolated from urine (n = 121), respiratory tract secretions (n = 28), blood (n = 6), wound (n = 2), urinary bladder catheter (n = 2), tracheal fluid (n = 2), joint fluid (n = 1) and sputum (n = 1). All patients were referred to three major hospitals (Ali ibn Abi Talib, Khatam al Anbiya and Buali Hospitals) of Zahedan during November 2011 to November 2012. The frequency of isolates from patients at outpatient, intensive care unit (ICU), emergency, surgery, internal, women, orthopedic, infants and maternity hospital wards were 87 (53.4%), 56 (34.4%), 5 (3.1%), 4 (2.5%), 3 (1.8%), 3 (1.8%), 3 (1.8%), 1 (0.6%) and 1 (0.6%), respectively. The bacterial isolates were recognized using usual biochemical tests.9 Standard bacterial strains including K. pneumoniae K.P 7881 containing blaCTX-M type as positive controls for PCR reactions, K. pneumoniae ATCC 700603 as positive control as well as Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 as negative control in antibiotic susceptibility testing were prepared from American Type Culture Collection Center. To determine the antimicrobial susceptibility of isolates, all isolates were plated on Mueller–Hinton agar and their susceptibilities to 18 different antibiotics were tested by Kirby-Bauer disc diffusion assay and the results were interpreted according to the CLSI procedure.10 The used discs (MAST, Merseyside, UK) were included cefotaxime (30 μg), ceftazidime (30 μg), ceftriaxone (30 μg), cefpodoxime (10 μg), cefepime (30 μg), aztreonam (30 μg), imipenem (10 μg), gentamicin (10 μg), streptomycin
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Table 1 Antimicrobial susceptibilities of the Klebsiella pneumoniae isolates Antibiotic Cefotaxime Ceftazidime Ceftriaxone Cefpodoxime Cefepime Aztreonam Imipenem Amoxicillin Nalidixic acid Ciprofloxacin Nitrofurantoin Cotrimoxazole Gentamicin Streptomycin Amikacin Chloramphenicol Tetracycline Colistin sulfate
Sensitive, n (%)
Intermediate, n (%)
Resistant, n (%)
Total, n (%)
96 (58.9) 101 (62.0) 96 (58.9) 96 (58.9) 117 (71.8) 96 (58.9) 152 (93.3) 0 (0.0) 110 (67.5) 125 (76.7) 66 (40.5) 95 (58.3) 122 (74.8) 113 (69.3) 156 (95.7) 147 (90.2) 105 (64.4) 161 (98.8)
1 (0.6) 7 (4.3) 2 (1.2) 0 (0.0) 13 (8.0) 8 (4.9) 3 (1.8) 0 (0.0) 17 (10.4) 7 (4.3) 5 (3.1) 1 (0.6) 0 (0.0) 5 (3.1) 0 (0.0) 0 (0.0) 2 (1.2) 0 (0.0)
66 (40.5) 55 (33.7) 65 (39.9) 67 (41.1) 33 (20.2) 59 (36.2) 8 (4.9) 163 (100.0) 36 (22.1) 31 (19.0) 92 (56.4) 67 (41.1) 41 (25.2) 45 (27.6) 7 (4.3) 16 (9.8) 56 (34.4) 2 (1.2)
163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100)
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(10 μg), amikacin (30 μg), ciprofloxacin (5 μg), nalidixic acid (30 μg), nitrofurantoin (300 μg), tetracycline (30 μg), chloramphenicol (30 μg), colistin sulphate (25 μg), amoxicillin (25 μg) and cotrimoxazole. For screening ESBL-producing isolates, the phenotypic confirmatory test were done by disc diffusion method with discs containing ceftazidime (30 μg) and ceftazidime/ clavulanic acid (30/10 μg), as well as cefotaxime (30 μg) and cefotaxime/clavulanic acid (30/10 μg).10 The plasmid DNA of isolates with ESBLs positive phenotype was extracted by AccuPrep Plasmid Nano-Plus Plasmid Mini Extraction Kit Cat. No.: K-3112 (Bioneer, Daejeon, South Korea). The plasmid DNA was used for detection of blaCTX-M groups. The primers and PCR conditions described by Pitout et al.11 were used to amplify group-specific blaCTX-M genes. PCR amplification for CTX-M beta-lactamase genes were carried out on a thermal cycler instrument (Bio-rad, California, USA). The PCR products were sequenced and analyzed using the BLAST program (www. ncbi.nlm.nih.gov = BLAST). The pattern of antibiotic resistance of all isolates for 18 different antibiotic agents is demonstrated in Table 1. In the initial disc diffusion test of isolates for cefotaxime, ceftazidime, ceftriaxone, cefpodoxime and aztreonam, 69 (42.3%) isolates showed reduced sensitivity, among which 51 (31.3%) isolates were passed the phenotypic confirmatory test (combination disc), thus were recognized as ESBLs producers. Meanwhile, the distribution prevalence of ESBLs producer isolates according to the hospital wards is shown in Table 2. PCR assay approved the presence of the blaCTX-M genes in all ESBLs producing isolates. CTX-M-I cluster was recognized in 46 (90.19%) isolates. Thirty three (64.7%) isolates possessed the CTX-M-III cluster. Additionally, 28 (54.9%) isolates were positive for either of CTX-M-I and CTX-M-III clusters. The CTXM-II and CTX-M-IV clusters were not detected in the studied isolates. The sequencing results demonstrated 344
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Table 2 Distribution of prevalence of ESBLs producer isolates divided to hospital wards Hospital ward
Number of isolates (%)
Number of ESBLs producer (%)
ICU Emergency Internal Women Maternity Orthopedic Surgery Infants Outpatient Total
56 (34.3) 5 (3.0) 3 (1.8) 3 (1.8) 1 (0.6) 3 (1.8) 4 (2.4) 1 (0.6) 87 (53.7) 163 (100.0)
23 (45.0) 4 (7.8) 1 (2.0) 1 (2.0) 0 (0.0) 1 (2.0) 1 (2.0) 0 (0.0) 20 (39.2) 51 (100.0)
ESBLs: extended-spectrum beta-lactamases; ICU: intensive care unit.
that the CTX-M-I and CTX-M-III cluster isolates were blaCTX-M-15 and blaCTX-M-8, respectively. Our results showed that 31.3% of K. pneumoniae strains isolated from patients, whether inpatient or outpatient, produced the ESBLs. Most ESBLs positive strains were isolated from inpatients related to the hospital wards (31 isolates), among which the ICU shared the biggest portion (23 isolates). Our findings highlights the importance of those bacteria that cause nosocomial infections and emphasizes that one of the risk factors for colonization and infection with ESBLs producing organisms is prolonged length of residence in an intensive care unit.12 Among ESBLs producing samples, 20 (39.2%) were patients who referred to the hospital outpatient laboratories. These findings suggest that ESBLs producing bacteria have found their way out of the hospital, and this is a great danger to the society. In conclusion, our results demonstrated that the resistance to the third-generation cephalosporins in clinical isolates of K. pneumoniae is relatively high in Zahedan. Furthermore, the most frequent genetic clusters in the region were found to be CTX-M-I and CTX-M-III encoding the CTX-M-15 and CTX-M-8 enzymes, respectively. In this study, we were not able to perform experiments for epidemiology purposes, and this is the limitation of
Shahraki-Zahedani et al. Prevalence of CTX-M-8 and CTX-M-15
our study, which makes the presented results somehow biassed.
Acknowledgements The authors appreciate all individuals who willingly participated in the current study.
Downloaded by [Weill Cornell Medical College] at 01:49 27 July 2016
Disclaimer Statements
Contributors Shahram Shahraki-Zahedani managed the research; Mehdi Moghadampour performed the tests and wrote the paper; Mohammad Bokaeian helped in managing the research; Alireza Ansari-Moghaddam contributed to data analysis. Funding This work was supported by a M.Sc. dissertation grant (M.Sc. thesis of Mehdi Moghadampour) from Zahedan University of Medical Sciences. Conflicts of interest The Authors declare that there is no conflict of interest. Ethics approval Ethics approval was received.
References 1 Paterson DL, Bonomo RA. Extended-spectrum beta-lactamases: a clinical update. Clin Microbiol Rev. 2005;18:657–86. 2 Monstein HJ, Ostholm-Balkhed A, Nilsson MV, Nilsson M, Dornbusch K, Nilsson LE. Multiplex PCR amplification assay for the detection
of blaSHV, blaTEM and blaCTX-M genes in Enterobacteriaceae. APMIS. 2007;115:1400–8. 3 Jacoby GA, Munoz-Price LS. The new beta-lactamases. N Engl J Med. 2005;352:380–91. 4 Bonnet R. Growing group of extended-spectrum beta-lactamases: the CTX-M enzymes. Antimicrob Agents Chemother. 2004;48:1–14. 5 Livermore DM, Canton R, Gniadkowski M, Nordmann P, Rossolini GM, Arlet G. CTX-M: changing the face of ESBLs in Europe. J Antimicrob Chemother. 2007;59:165–74. 6 Bradford PA. Extended-spectrum beta-lactamases in the 21st century: characterization, epidemiology, and detection of this important resistance threat. Clin Microbiol Rev. 2001;14:933–951, [table of contents]. 7 Feizabadi MM, Delfani S, Raji N, Majnooni A, Aligholi M, Shahcheraghi F. Distribution of bla(TEM), bla(SHV), bla(CTX-M) genes among clinical isolates of Klebsiella pneumoniae at Labbafinejad Hospital, Tehran, Iran. Microb Drug Resist. 2010;16:49–53. 8 Nematzadeh S, Shahcheraghi F, Feizabadi MM, Nikbin VS, Nasehi L. Molecular characterization of CTX-Mbeta-lactamases among Klebsiella pneumoniae isolated from patients at Tehran hospitals. Indian J Med Microbiol. 2011;29:254–7. 9 Podschun R, Ullmann U. Klebsiella spp. as nosocomial pathogens: epidemiology, taxonomy, typing methods, and pathogenicity factors. Clin Microbiol Rev. 1998;11:589–603. 10 Cockerill FR, Wikler MA, Alder J, Dudley MN, Eliopoulos GM, Ferraro MJ, et al. Performance standards for antimicrobial disk susceptibility tests. 32. approved standard – eleventh edition. Wayne, PA: CLSI; 2012; p. 1–76. 11 Pitout JD, Hossain A, Hanson ND. Phenotypic and molecular detection of CTX-M-beta-lactamases produced by Escherichia coli and Klebsiella spp. J Clin Microbiol. 2004;42:5715–21. 12 Gupta A, Ampofo K, Rubenstein D, Saiman L. Extended spectrum beta lactamase-producing Klebsiella pneumoniae infections: a review of the literature. J Perinatol. 2003;23:439–43.
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ISSN: 1120-009X (Print) 1973-9478 (Online) Journal homepage: http://www.tandfonline.com/loi/yjoc20
Prevalence of CTX-M-8 and CTX-M-15 type extended-spectrum beta-lactamases between Klebsiella pneumoniae spp. isolated from Zahedan, Southeast Iran Shahram Shahraki-Zahedani, Mehdi Moghadampour, Mohammad Bokaeian & Alireza Ansari-Moghaddam To cite this article: Shahram Shahraki-Zahedani, Mehdi Moghadampour, Mohammad Bokaeian & Alireza Ansari-Moghaddam (2016) Prevalence of CTX-M-8 and CTX-M-15 type extended-spectrum beta-lactamases between Klebsiella pneumoniae spp. isolated from Zahedan, Southeast Iran, Journal of Chemotherapy, 28:4, 343-345, DOI: 10.1179/1973947815Y.0000000008 To link to this article: http://dx.doi.org/10.1179/1973947815Y.0000000008
Published online: 27 Jul 2016.
Submit your article to this journal
View related articles
View Crossmark data
Citing articles: 1 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=yjoc20 Download by: [Weill Cornell Medical College]
Date: 27 July 2016, At: 01:49
Brief Communication
Prevalence of CTX-M-8 and CTX-M-15 type extended-spectrum beta-lactamases between Klebsiella pneumoniae spp. isolated from Zahedan, Southeast Iran Shahram Shahraki-Zahedani1,2, Mehdi Moghadampour2, Mohammad Bokaeian3, Alireza Ansari-Moghaddam4 Infectious Diseases and Tropical Medicine Research Center, Zahedan University of Medical Sciences, Zahedan, Iran, 2Department of Microbiology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran, 3Department of Laboratory Sciences, School of Paramedical Sciences, Zahedan University of Medical Sciences, Zahedan, Iran, 4Health Promotion Research Center, Zahedan University of Medical Sciences, Zahedan, Iran
Downloaded by [Weill Cornell Medical College] at 01:49 27 July 2016
1
Extended-spectrum beta-lactamases (ESBLs) are bacterial plasmid-encoded enzymes that cause bacterial resistance against the penicillins, the first-, second- and third-generation cephalosporins, as well as aztreonam by hydrolysing these antibiotics. ESBLs are inhibited by beta-lactamase inhibitors such as clavulanic acid.1 On the base of Ambler et al. classification, beta-lactamase enzymes are divided into four classes designated as classes A–D.2 Most of the ESBLs are classified as class A.3 Class A ESBLs form a heterogeneous molecular group and are included of three major groups: the TEM, SHV and CTX-M types.4 The CTX-M type ESBLs are developed from TEM and SHV ESBLs and are the commonest group of ESBLs that according to their amino acid sequence similarities are divided into five subgroups including CTX-M-I, CTXM-II, CTX-M-III, CTX-M-IV and CTX-M-V.1,3,4 During the last decade, there has been a shift in the detected ESBL enzymes from the classic TEM and SHV enzyme families, which were mainly detected in the 1980s and 1990s, to the CTX-M family, which was dominated in the last decade.5 The prevalence of ESBLs among clinical isolates of Enterobacteriaceae and especially Klebsiella pneumoniae strains has become a worldwide problem.6 Moreover, several studies have reported high prevalence of these enzymes (CTX-M type ESBLs) in IRAN.7,8 The aim of this sectional-descriptive study was to determine the prevalence of ESBLs-producing isolates of K. pneumoniae at three major hospitals of Zahedan and to characterize the blaCTX-M gene by polymerase chain reaction (PCR) and DNA sequencing. To the best of our knowledge, this Correspondence to: Mehdi Moghadampour, Department of Microbiology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran. Email [email protected]
© 2016 Edizioni Scientifiche per l'Informazione su Farmaci e Terapia DOI 10.1179/1973947815Y.0000000008
is the first report from a southeastern region of Iran examining the presence of K. pneumoniae isolates producing CTX-M genes. One hundred sixty three unrepeated clinical isolates of K. pneumoniae were isolated from urine (n = 121), respiratory tract secretions (n = 28), blood (n = 6), wound (n = 2), urinary bladder catheter (n = 2), tracheal fluid (n = 2), joint fluid (n = 1) and sputum (n = 1). All patients were referred to three major hospitals (Ali ibn Abi Talib, Khatam al Anbiya and Buali Hospitals) of Zahedan during November 2011 to November 2012. The frequency of isolates from patients at outpatient, intensive care unit (ICU), emergency, surgery, internal, women, orthopedic, infants and maternity hospital wards were 87 (53.4%), 56 (34.4%), 5 (3.1%), 4 (2.5%), 3 (1.8%), 3 (1.8%), 3 (1.8%), 1 (0.6%) and 1 (0.6%), respectively. The bacterial isolates were recognized using usual biochemical tests.9 Standard bacterial strains including K. pneumoniae K.P 7881 containing blaCTX-M type as positive controls for PCR reactions, K. pneumoniae ATCC 700603 as positive control as well as Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 as negative control in antibiotic susceptibility testing were prepared from American Type Culture Collection Center. To determine the antimicrobial susceptibility of isolates, all isolates were plated on Mueller–Hinton agar and their susceptibilities to 18 different antibiotics were tested by Kirby-Bauer disc diffusion assay and the results were interpreted according to the CLSI procedure.10 The used discs (MAST, Merseyside, UK) were included cefotaxime (30 μg), ceftazidime (30 μg), ceftriaxone (30 μg), cefpodoxime (10 μg), cefepime (30 μg), aztreonam (30 μg), imipenem (10 μg), gentamicin (10 μg), streptomycin
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Table 1 Antimicrobial susceptibilities of the Klebsiella pneumoniae isolates Antibiotic Cefotaxime Ceftazidime Ceftriaxone Cefpodoxime Cefepime Aztreonam Imipenem Amoxicillin Nalidixic acid Ciprofloxacin Nitrofurantoin Cotrimoxazole Gentamicin Streptomycin Amikacin Chloramphenicol Tetracycline Colistin sulfate
Sensitive, n (%)
Intermediate, n (%)
Resistant, n (%)
Total, n (%)
96 (58.9) 101 (62.0) 96 (58.9) 96 (58.9) 117 (71.8) 96 (58.9) 152 (93.3) 0 (0.0) 110 (67.5) 125 (76.7) 66 (40.5) 95 (58.3) 122 (74.8) 113 (69.3) 156 (95.7) 147 (90.2) 105 (64.4) 161 (98.8)
1 (0.6) 7 (4.3) 2 (1.2) 0 (0.0) 13 (8.0) 8 (4.9) 3 (1.8) 0 (0.0) 17 (10.4) 7 (4.3) 5 (3.1) 1 (0.6) 0 (0.0) 5 (3.1) 0 (0.0) 0 (0.0) 2 (1.2) 0 (0.0)
66 (40.5) 55 (33.7) 65 (39.9) 67 (41.1) 33 (20.2) 59 (36.2) 8 (4.9) 163 (100.0) 36 (22.1) 31 (19.0) 92 (56.4) 67 (41.1) 41 (25.2) 45 (27.6) 7 (4.3) 16 (9.8) 56 (34.4) 2 (1.2)
163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100) 163 (100)
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(10 μg), amikacin (30 μg), ciprofloxacin (5 μg), nalidixic acid (30 μg), nitrofurantoin (300 μg), tetracycline (30 μg), chloramphenicol (30 μg), colistin sulphate (25 μg), amoxicillin (25 μg) and cotrimoxazole. For screening ESBL-producing isolates, the phenotypic confirmatory test were done by disc diffusion method with discs containing ceftazidime (30 μg) and ceftazidime/ clavulanic acid (30/10 μg), as well as cefotaxime (30 μg) and cefotaxime/clavulanic acid (30/10 μg).10 The plasmid DNA of isolates with ESBLs positive phenotype was extracted by AccuPrep Plasmid Nano-Plus Plasmid Mini Extraction Kit Cat. No.: K-3112 (Bioneer, Daejeon, South Korea). The plasmid DNA was used for detection of blaCTX-M groups. The primers and PCR conditions described by Pitout et al.11 were used to amplify group-specific blaCTX-M genes. PCR amplification for CTX-M beta-lactamase genes were carried out on a thermal cycler instrument (Bio-rad, California, USA). The PCR products were sequenced and analyzed using the BLAST program (www. ncbi.nlm.nih.gov = BLAST). The pattern of antibiotic resistance of all isolates for 18 different antibiotic agents is demonstrated in Table 1. In the initial disc diffusion test of isolates for cefotaxime, ceftazidime, ceftriaxone, cefpodoxime and aztreonam, 69 (42.3%) isolates showed reduced sensitivity, among which 51 (31.3%) isolates were passed the phenotypic confirmatory test (combination disc), thus were recognized as ESBLs producers. Meanwhile, the distribution prevalence of ESBLs producer isolates according to the hospital wards is shown in Table 2. PCR assay approved the presence of the blaCTX-M genes in all ESBLs producing isolates. CTX-M-I cluster was recognized in 46 (90.19%) isolates. Thirty three (64.7%) isolates possessed the CTX-M-III cluster. Additionally, 28 (54.9%) isolates were positive for either of CTX-M-I and CTX-M-III clusters. The CTXM-II and CTX-M-IV clusters were not detected in the studied isolates. The sequencing results demonstrated 344
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Table 2 Distribution of prevalence of ESBLs producer isolates divided to hospital wards Hospital ward
Number of isolates (%)
Number of ESBLs producer (%)
ICU Emergency Internal Women Maternity Orthopedic Surgery Infants Outpatient Total
56 (34.3) 5 (3.0) 3 (1.8) 3 (1.8) 1 (0.6) 3 (1.8) 4 (2.4) 1 (0.6) 87 (53.7) 163 (100.0)
23 (45.0) 4 (7.8) 1 (2.0) 1 (2.0) 0 (0.0) 1 (2.0) 1 (2.0) 0 (0.0) 20 (39.2) 51 (100.0)
ESBLs: extended-spectrum beta-lactamases; ICU: intensive care unit.
that the CTX-M-I and CTX-M-III cluster isolates were blaCTX-M-15 and blaCTX-M-8, respectively. Our results showed that 31.3% of K. pneumoniae strains isolated from patients, whether inpatient or outpatient, produced the ESBLs. Most ESBLs positive strains were isolated from inpatients related to the hospital wards (31 isolates), among which the ICU shared the biggest portion (23 isolates). Our findings highlights the importance of those bacteria that cause nosocomial infections and emphasizes that one of the risk factors for colonization and infection with ESBLs producing organisms is prolonged length of residence in an intensive care unit.12 Among ESBLs producing samples, 20 (39.2%) were patients who referred to the hospital outpatient laboratories. These findings suggest that ESBLs producing bacteria have found their way out of the hospital, and this is a great danger to the society. In conclusion, our results demonstrated that the resistance to the third-generation cephalosporins in clinical isolates of K. pneumoniae is relatively high in Zahedan. Furthermore, the most frequent genetic clusters in the region were found to be CTX-M-I and CTX-M-III encoding the CTX-M-15 and CTX-M-8 enzymes, respectively. In this study, we were not able to perform experiments for epidemiology purposes, and this is the limitation of
Shahraki-Zahedani et al. Prevalence of CTX-M-8 and CTX-M-15
our study, which makes the presented results somehow biassed.
Acknowledgements The authors appreciate all individuals who willingly participated in the current study.
Downloaded by [Weill Cornell Medical College] at 01:49 27 July 2016
Disclaimer Statements
Contributors Shahram Shahraki-Zahedani managed the research; Mehdi Moghadampour performed the tests and wrote the paper; Mohammad Bokaeian helped in managing the research; Alireza Ansari-Moghaddam contributed to data analysis. Funding This work was supported by a M.Sc. dissertation grant (M.Sc. thesis of Mehdi Moghadampour) from Zahedan University of Medical Sciences. Conflicts of interest The Authors declare that there is no conflict of interest. Ethics approval Ethics approval was received.
References 1 Paterson DL, Bonomo RA. Extended-spectrum beta-lactamases: a clinical update. Clin Microbiol Rev. 2005;18:657–86. 2 Monstein HJ, Ostholm-Balkhed A, Nilsson MV, Nilsson M, Dornbusch K, Nilsson LE. Multiplex PCR amplification assay for the detection
of blaSHV, blaTEM and blaCTX-M genes in Enterobacteriaceae. APMIS. 2007;115:1400–8. 3 Jacoby GA, Munoz-Price LS. The new beta-lactamases. N Engl J Med. 2005;352:380–91. 4 Bonnet R. Growing group of extended-spectrum beta-lactamases: the CTX-M enzymes. Antimicrob Agents Chemother. 2004;48:1–14. 5 Livermore DM, Canton R, Gniadkowski M, Nordmann P, Rossolini GM, Arlet G. CTX-M: changing the face of ESBLs in Europe. J Antimicrob Chemother. 2007;59:165–74. 6 Bradford PA. Extended-spectrum beta-lactamases in the 21st century: characterization, epidemiology, and detection of this important resistance threat. Clin Microbiol Rev. 2001;14:933–951, [table of contents]. 7 Feizabadi MM, Delfani S, Raji N, Majnooni A, Aligholi M, Shahcheraghi F. Distribution of bla(TEM), bla(SHV), bla(CTX-M) genes among clinical isolates of Klebsiella pneumoniae at Labbafinejad Hospital, Tehran, Iran. Microb Drug Resist. 2010;16:49–53. 8 Nematzadeh S, Shahcheraghi F, Feizabadi MM, Nikbin VS, Nasehi L. Molecular characterization of CTX-Mbeta-lactamases among Klebsiella pneumoniae isolated from patients at Tehran hospitals. Indian J Med Microbiol. 2011;29:254–7. 9 Podschun R, Ullmann U. Klebsiella spp. as nosocomial pathogens: epidemiology, taxonomy, typing methods, and pathogenicity factors. Clin Microbiol Rev. 1998;11:589–603. 10 Cockerill FR, Wikler MA, Alder J, Dudley MN, Eliopoulos GM, Ferraro MJ, et al. Performance standards for antimicrobial disk susceptibility tests. 32. approved standard – eleventh edition. Wayne, PA: CLSI; 2012; p. 1–76. 11 Pitout JD, Hossain A, Hanson ND. Phenotypic and molecular detection of CTX-M-beta-lactamases produced by Escherichia coli and Klebsiella spp. J Clin Microbiol. 2004;42:5715–21. 12 Gupta A, Ampofo K, Rubenstein D, Saiman L. Extended spectrum beta lactamase-producing Klebsiella pneumoniae infections: a review of the literature. J Perinatol. 2003;23:439–43.
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