Detection of ESBL- and AmpC-producing E. coli isolates from urinary tract infections


Department of Microbiology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran


Background: Extended-spectrum β-lactamases (ESBLs) and AmpC enzymes have been observed in virtually all species of the family Enterobacteriaceae. The β-lactamase producing bacteria cause many serious infections, including urinary tract infections. These enzymes are predominantly plasmid mediated. There are no recommended guidelines for detection of this resistance mechanism and there is a need to address this issue as much as the detection of ESBLs. This study was undertaken to characterize ESBL and AmpC producers among Escherichia coli by polymerase chain reaction (PCR), which were initially screened by phenotypic method.
Materials and Methods: A total of 90 isolates of E. coli were recovered from the urinary tract during a 7-month period, and were screened for ESBLs and AmpC production by disk diffusion test using cefoxitin (30 μg) disks and confirmed by combined disk diffusion test using phenyl boronic acid. The presence of genes encoding CIT, FOX, and TEM was detected by PCR.
Results: On disk diffusion test, 59 of 90 isolates were resistant to third generation of cephalosporins; of these 37 (62.7%) and 3 (5%) were ESBL and AmpC producers, respectively. PCR showed that 29 (49.1%) and 3 (5%) were positive for blaTEM and blaCMY-2 , respectively.
Conclusion: ESBL- and AmpC-producing E. coli isolates cause significant resistance to cephalosporin. There is a need for a correct and reliable phenotypic test to identify AmpC β-lactamases and to discriminate between AmpC and ESBL producers. This work showed that boronic acid can differentiate ESBL enzymes from AmpC enzymes.


Sharma J, Sharma M, Ray P. Detection of TEM and SHV genes in Escherichia coli and Klebsiella pneumoniae isolates in a tertiary care hospital from India. Indian J Med Res 2010;132:332-6.  Back to cited text no. 1
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Moges AF, Genetu A, Mengistu G. Antibiotic sensitivities of common bacterial pathogens in urinary tract infections at Gonder hospital, Ethiopia. East Afr Med J 2002;79:140-2.  Back to cited text no. 2
de Souza RM, Olsburgh J. Urinary tract infection in the renal transplant patient. Nat Clin Pract Nephrol 2008;4:252-64.  Back to cited text no. 3
Rodríguez-Baño J, Navarro MD, Romero L, Martínez-Martínez L, Muniain MA, Perea EJ, et al. Epidemiology and clinical features of infections caused by extended-spectrum beta-lactamase-producing Escherichia coli in nonhospitalized patients. J Clin Microbiol 2004;42:1089-94.  Back to cited text no. 4
Hernández JR, Martínez-Martínez L, Cantón R, Coque TM, Pascual A; Spanish Group for Nosocomial Infections (GEIH). Nationwide study of Escherichia coli and Klebsiella pneumoniae producing extended-spectrum beta-lactamases in Spain. Antimicrob Agents Chemother 2005;49:2122-5.  Back to cited text no. 5
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;46:1481-91.  Back to cited text no. 6
Kalematizadeh E. Determination of extended-spectrum beta-lactamases bacteria in Escherichia coli and Klebsiella pneumoniae. Mashhad: Mashhad University of Medical Sciences; 2008.  Back to cited text no. 7
Bradford PA. Extended-spectrum beta-lactamases in the 21 st century: Characterization, epidemiology, and detection of this important resistance threat. Clin Microbiol Rev 2001;14:933-51, table of contents.  Back to cited text no. 8
Ramazanzadeh R, Farhadifar F, Mansouri M. Etiology and antibiotic resistance patterns of community-acquired extended-spectrum beta-lactamase-producing gram negative isolates in Sanandaj. Res J Med Sci 2010;4:243-7.  Back to cited text no. 9
Philippon A, Labia R, Jacoby G. Extended-spectrum beta-lactamases. Antimicrob Agents Chemother 1989;33:1131-6.  Back to cited text no. 10
Goussard S, Courvalin P. Updated sequence information for TEM beta-lactamase genes. Antimicrob Agents Chemother 1999;43:367-70.  Back to cited text no. 11
Jacoby GA, Munoz-Price LS. The new beta-lactamases. N Engl J Med 2005;352:380-91.  Back to cited text no. 12
Shayan S, Bokaeian M, Shahraki S. Prevalence and molecular characterization of AmpC-producing clinical isolates of Escherichia coli from southeastern Iran. Microb Drug Resist 2014;20:104-7.  Back to cited text no. 13
Clinical and Laboratory Standards Institute. Performance Standards for Antimicrobial Susceptibility Testing: Twentieth Informational Supplement M100-S20. Wayne, PA: Clinical and Laboratory Standards Institute (CLSI); 201032-43.  Back to cited text no. 14
Peter-Getzlaff S, Polsfuss S, Poledica M, Hombach M, Giger J, Böttger EC, et al. Detection of AmpC beta-lactamase in Escherichia coli: Comparison of three phenotypic confirmation assays and genetic analysis. J Clin Microbiol 2011;49:2924-32.  Back to cited text no. 15
Coudron PE. Inhibitor-based methods for detection of plasmid-mediated AmpC beta-lactamases in Klebsiella spp., Escherichia coli, and Proteus mirabilis. J Clin Microbiol 2005;43:4163-7.  Back to cited text no. 16
Goossens H. MYSTIC (Meropenem Yearly Susceptibility Test Information Collection) results from Europe: Comparison of antibiotic susceptibilities between countries and centre types. J Antimicrob Chemother 2000;46 Suppl B:39-52.  Back to cited text no. 17
Sabaté M, Miró E, Navarro F, Vergés C, Aliaga R, Mirelis B, et al. Beta-lactamases involved in resistance to broad-spectrum cephalosporins in Escherichia coli and Klebsiella spp. clinical isolates collected between 1994 and 1996, in Barcelona (Spain). J Antimicrob Chemother 2002;49:989-97.  Back to cited text no. 18
Mansouri S, Kalantar D, Asadollahi P, Taherikalani M, Emaneini M. Characterization of klebsiella pneumoniae strains producing extended spectrum beta-lactamases and AMPC type beta-lactamases isolated from hospitalized patients in kerman, Iran. Roum Arch Microbiol Immunol 2012;71:81-6.  Back to cited text no. 19
Niakan M, Mohsen C, Metvaei AR. Prevalence of AmpC type extended spectrum beta lactamases genes in clinical, isolates of Klebsiella pneumonia. IJMS 2008;2:1-8.[Persian]  Back to cited text no. 20
Pitout JD, Gregson DB, Church DL, Laupland KB. Population-based laboratory surveillance for AmpC beta-lactamase-producing Escherichia coli, Calgary. Emerg Infect Dis 2007;13:443-8.  Back to cited text no. 21
Jabeen K, Zafar A, Hasan R. Frequency and sensitivity pattern of extended-spectrum beta-lactamase producing isolates in a tertiary care hospital laboratory of Pakistan. J Pak Med Assoc 2005;55:436-9.  Back to cited text no. 22
Yu WL, Chuang YC, Walther-Rasmussen J. Extended-spectrum beta -lactamases in Taiwan: Epidemiology, detection, treatment and infection control. J Microbiol Immunol Infect 2006;39:264-77.  Back to cited text no. 23
Behrouzi A, Rahbar M, Vandyousefi J. Frequency of extended spectrum beta-lactamase (ESBLS) producing Escherichia coli and Klebseilla pneumonia isolated from urine in an Iranian 1000-bed tertiary care hospital AJMR 2010;4:881-4.  Back to cited text no. 24
Feizabadi MM, Mohamadi-Yeganeh S, Mirsalehian A, Mirafshar SM, Mahboobi M, Nili F, et al. Genetic characterization of ESBL producing strains of Klebsiella pneumoniae from Tehran hospitals. J Infect Dev Ctries 2010;4:609-15.  Back to cited text no. 25
Taºli H, Bahar IH. Molecular characterization of TEM- and SHV-derived extended-spectrum beta-lactamases in hospital-based Enterobacteriaceae in Turkey. Jpn J Infect Dis 2005;58:162-7.  Back to cited text no. 26
Al-Agamy MH, Shibl AM, Zaki SA, Tawfik AF. Antimicrobial resistance pattern and prevalence of metallo-â-lactamases in Pseudomonas aeruginosa from Saudi Arabia. Afr J Microbiol Res 2011;5:5528-33.  Back to cited text no. 27
Bogaerts P, Rodriguez-Villalobos H, Laurent C, Deplano A, Struelens MJ, Glupczynski Y. Emergence of extended-spectrum-AmpC-expressing Escherichia coli isolates in Belgian hospitals. J Antimicrob Chemother 2009;63:1073-5.  Back to cited text no. 28
Briñas L, Lantero M, de Diego I, Alvarez M, Zarazaga M, Torres C. Mechanisms of resistance to expanded-spectrum cephalosporins in Escherichia coli isolates recovered in a Spanish hospital. J Antimicrob Chemother 2005;56:1107-10.  Back to cited text no. 29
Ahmed MO, Clegg PD, Williams NJ, Baptiste KE, Bennett M. Antimicrobial resistance in equine faecal Escherichia coli isolates from North West England. Ann Clin Microbiol Antimicrob 2010;9:12.  Back to cited text no. 30
Thomson KS. Controversies about extended-spectrum and AmpC beta-lactamases. Emerg Infect Dis 2001;7:333-6.  Back to cited text no. 31