Document Type : Original Research


1 Department of Microbiology, Faculty of Medicine, Shahed University, Tehran, Iran.

2 Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran


Background & Objective: Escherichia coli (E. coli) is a leading cause of urinary tract infections becoming resistant against beta-lactams and cephalosporins through different mechanisms, including ESBL production due to the presence of ESBL specific genes, including blaCTX-M and blaTEM. The purpose of the present study was to detect the uropathogenic E. coli strains producing the ESBL.
Methods: A total of 100 isolates of uropathogenic E. coli were randomly selected in a period of 6 months and their resistances to a number of antibiotics including amoxicillin, amikacin, gentamicin, ciprofloxacin, ceftazidime, cefotaxime, ceftriaxone, ceftizoxime, nalidixic acid, and nitrofurantoin were determined. Then, DDT test was used to detect the presence of ESBL. Finally, the presence of blaCTX-M and blaTEM resistance genes was analyzed by PCR method.
Results: The resistance profile of bacterial isolates to the antibiotics was as follows: amoxicillin: 16.7%, amikacin: 7.8%, gentamicin: 20.3%, ciprofloxacin: 35.5/%, ceftazidime: 35.0%, cefotaxime: 40.0%, ceftriaxone: 41.3%, nalidixic acid: 64.0%, nitrofurantoin: 9.7%, and ceftizoxime: 100%. Of these, 28 isolates (28%) were reported to be resistant to cefotaxime, ceftazidime, and ceftriaxone. In DDT test, 21 ESBL positive cases (21%) were detected. PCR results showed that the presence of blaCTX-M and blaTEM genes in the isolates were 21% and 20%, respectively. 
Conclusion: Regarding the production of ESBL by some E. coli isolates, phenotypic detection of ESBL-producing isolates is routinely suggested in the laboratories. Likewise, the treatment regimen should be selected regarding the ESBL production to avoid treatment failure. 


Main Subjects

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  1. Zaniani FR, Meshkat Z, Nasab MN, Khaje-Karamadini M, Ghazvini K, Rezaee A, et al. The prevalence of TEM and SHV genes among extended-spectrum beta-lactamases producing Escherichia coli and Klebsiella pneumoniae. Iran J Basic Med Sci. 2012;15(1):654-60. [PMID] [PMCID]
  2. Bradford PA. Extended-spectrum β-lactamases in the 21st century: characterization, epidemiology, and detection of this important resistance threat. Clin Microbiol Rev. 2001;14(4):933-51. [DOI:10.1128/CMR.14.4.933-951.2001] [PMID] [PMCID]
  3. Kim YK, Pai H, Lee HJ, Park SE, Choi EH, Kim J, et al. Bloodstream infections by extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in children: epidemiology and clinical outcome. Antimicrob Agents Chemother. 2002;46(5):1481-91. [DOI:10.1128/AAC.46.5.1481-1491.2002] [PMID] [PMCID]
  4. Haj Ebrahim Tehrani F, Moradi M, Ghorbani N. Bacterial Etiology and Antibiotic Resistance Patterns in Neonatal Sepsis in Tehran during 2006-2014. Iran J Pathol. 2017;12(4):356-61. [DOI:10.30699/ijp.2017.27992] [PMID] [PMCID]
  5. Livermore DM. beta-Lactamases in laboratory and clinical resistance. Clin Microbiol Rev. 1995;8(4):557-84. [DOI:10.1128/CMR.8.4.557] [PMID] [PMCID]
  6. Tenover FC, Raney PM, Williams PP, Rasheed JK, Biddle JW, Oliver A, et al. Evaluation of the NCCLS extended-spectrum beta-lactamase confirmation methods for Escherichia coli with isolates collected during Project ICARE. J Clin Microbiol. 2003;41(7):3142-6. [DOI:10.1128/JCM.41.7.3142-3146.2003] [PMID] [PMCID]
  7. Darvishi M, Forootan M, Nazer MR, Karimi E, Noori M. Nosocomial Infections, Challenges and Threats: A Review Article. Iran J Med Microbiol. 2020;14(2):162-81. [DOI:10.30699/ijmm.14.2.162]
  8. Eliopoulos GM, Bush K. New β-lactamases in gram-negative bacteria: diversity and impact on the selection of antimicrobial therapy. Clin Infect Dis. 2001;32(7):1085-9. [DOI:10.1086/319610] [PMID]
  9. Paterson DL, Bonomo RA. Extended-spectrum beta-lactamases: a clinical update. Clin Microbiol Rev. 2005;18(4):657-86. [DOI:10.1128/CMR.18.4.657-686.2005] [PMID] [PMCID]
  10. Mirzaee M, Pourmand M, Chitsaz M, Mansouri S. Antibiotic resistance to third generation cephalosporins due to CTX-M-Type extended-spectrum β-lactamases in clinical isolates of Escherichia coli. Iran J Public Health. 2009;38(1):10-7. [Article]
  11. Pallecchi L, Bartoloni A, Fiorelli C, Mantella A, Di Maggio T, Gamboa H, et al. Rapid dissemination and diversity of CTX-M extended-spectrum beta-lactamase genes in commensal Escherichia coli isolates from healthy children from low-resource settings in Latin America. Antimicrob Agents Chemother. 2007;51(8):2720-5. [DOI:10.1128/AAC.00026-07] [PMID] [PMCID]
  12. Chen Y, Delmas J, Sirot J, Shoichet B, Bonnet R. Atomic resolution structures of CTX-M beta-lactamases: extended spectrum activities from increased mobility and decreased stability. J Mol Biol. 2005;348(2):349-62. [DOI:10.1016/j.jmb.2005.02.010] [PMID]
  13. Gupta V. An update on newer beta-lactamases. Indian J Med Res. 2007;126(5):417-27. [PMID]
  14. Mlynarczyk G, Mlynarczyk A, Bilewska A, Dukaczewska A, Golawski C, Kicman A, et al. [High effectiveness of the method with cefpirome in detection of extended-spectrum beta-lactamases in different species of gram-negative bacilli]. Med Dosw Mikrobiol. 2006;58(1):59-65. [PMID]
  15. Zamanzad B, Deyham B, Nafisi M, Karimi A, Farokhi E. The Frequency of TEM-1 Gene in Extended Spectrum Beta Lactamases Producing Escherichia coli, Klebsiella pneumoniae and Enterobacter Strains Isolated from Hospital Clinical Samples Using PCR. Sci J Hamadan Univ Med Sci. 2008;14(4):19-25.
  16. Perilli M, Dell'Amico E, Segatore B, de Massis MR, Bianchi C, Luzzaro F, et al. Molecular characterization of extended-spectrum beta-lactamases produced by nosocomial isolates of Enterobacteriaceae from an Italian nationwide survey. J Clin Microbiol. 2002;40(2):611-4. [DOI:10.1128/JCM.40.2.611-614.2002] [PMID] [PMCID]
  17. Haghi F, Zeighami H, Keramati N, Hemmati F, Hajiahmadi F. Frequency of TEM extended spectrum beta lactamase producing Escherichia coli in clinical specimens by phenotypic and molecular methods in Zanjan. Zanjan Univ Med Sci J. 2013;21(85):55-63.
  18. Clinical and Laboratory Standards Institute. Performance Standards for Antimicrobial Susceptibility Testing; 21st Informational Supplement. M100-S21. CLSI Wayne, PA; 2011. [Link]
  19. Queipo-Ortuño MI, Colmenero JDD, Macias M, Bravo MJ, Morata P. Preparation of bacterial DNA template by boiling and effect of immunoglobulin G as an inhibitor in real-time PCR for serum samples from patients with brucellosis. Clin Vaccine Immunol. 2008;15(2):293-6. [DOI:10.1128/CVI.00270-07] [PMID] [PMCID]
  20. Oliver A, Weigel LM, Rasheed JK, McGowan JE, Jr., Raney P, Tenover FC. Mechanisms of decreased susceptibility to cefpodoxime in Escherichia coli. Antimicrob Agents Chemother. 2002;46(12):3829-36. [DOI:10.1128/AAC.46.12.3829-3836.2002] [PMID] [PMCID]
  21. Cavallo JD, Leblanc F, Fabre R, Fourticq-Esqueoute A, Group d'Etude le la Resistance de PaaB. [Survey of the antibiotic sensitivity of Pseudomonas aeruginosa in France and the distribution of beta-lactam resistance mechanisms: the GERPB 1999 study]. Pathol Biol (Paris). 2001;49(7):534-9. [DOI:10.1016/S0369-8114(01)00213-9]
  22. Rupp ME, Fey PD. Extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae: considerations for diagnosis, prevention and drug treatment. Drugs. 2003;63(4):353-65. [DOI:10.2165/00003495-200363040-00002] [PMID]
  23. 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(12):5715-21. [DOI:10.1128/JCM.42.12.5715-5721.2004] [PMID] [PMCID]
  24. Bell JM, Chitsaz M, Turnidge JD, Barton M, Walters LJ, Jones RN. Prevalence and significance of a negative extended-spectrum beta-lactamase (ESBL) confirmation test result after a positive ESBL screening test result for isolates of Escherichia coli and Klebsiella pneumoniae: results from the SENTRY Asia-Pacific Surveillance Program. J Clin Microbiol. 2007;45(5):1478-82. [DOI:10.1128/JCM.02470-06] [PMID] [PMCID]
  25. Akram M, Shahid M, Khan AU. Etiology and antibiotic resistance patterns of community-acquired urinary tract infections in JNMC Hospital Aligarh, India. Ann Clin Microbiol Antimicrob. 2007;6(1):4. [DOI:10.1186/1476-0711-6-4] [PMID] [PMCID]
  26. Lewis JS, Herrera M, Wickes B, Patterson JE, Jorgensen JH. First report of the emergence of CTX-M-type extended-spectrum β-lactamases (ESBLs) as the predominant ESBL isolated in a US health care system. Antimicrob Agents Chemother. 2007;51(11):4015-21. [DOI:10.1128/AAC.00576-07] [PMID] [PMCID]
  27. Pitout JD, Nordmann P, Laupland KB, Poirel L. Emergence of Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBLs) in the community. J Antimicrob Chemother. 2005;56(1):52-9. [DOI:10.1093/jac/dki166] [PMID]
  28. Pourakbari B, Ferdosian F, Mahmoudi S, Teymuri M, Sabouni F, Heydari H, et al. Increase resistant rates and ESBL production between E. coli isolates causing urinary tract infection in young patients from Iran. Braz J Microbiol. 2012;43(2):766-9. [DOI:10.1590/S1517-83822012000200041] [PMID] [PMCID]
  29. Mohammadi-Mehr M, Feizabadi M. Antimicrobial resistance pattern of Gram-negative bacilli isolated from patients at ICUs of Army hospitals in Iran. Iran J Microbiol. 2011;3(1):26-30. [Article]