Characterization of Enterobacteriaceae isolates obtained from a tertiary care hospital in Mexico, which produces extended-spectrum β-lactamase

Rayo Morfín-Otero, Soraya Mendoza-Olazarán, Jesús Silva-Sánchez, Eduardo Rodríguez-Noriega, Jorge Laca-Díaz, Perla Tinoco-Carrillo, Luis Petersen, Perla López, Fernando Reyna-Flores, Dolores Alcantar-Curiel, Ulises Garza-Ramos, Elvira Garza-González

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


The prevalence and genetic characteristics of Escherichia coli and Klebsiella pneumoniae clinical isolates producing extended-spectrum β-lactamase (ESBL) were examined. Between October 2010 and March 2011, E. coli (n=460) and K. pneumoniae (n=78) isolates were collected at a tertiary care hospital in Guadalajara, Mexico. The minimum inhibitory concentration (MIC) for each isolate was determined using a broth microdilution method, and ESBL production was assayed. The presence of β-lactamase genes, blaSHV, blaCTX-M, and blaTLA-1, was detected by PCR and confirmed with sequencing. Only ESBL-producing isolates were further subjected to pulsed-field gel electrophoresis (PFGE) and plasmid profiling. All of the ESBL isolates were multidrug resistant and 75/460 (16.3%) E. coli isolates and 21/78 (26.9%) K. pneumoniae isolates were found to produce ESBL. For the E. coli isolates, >95% susceptibility to amikacin, meropenem, fosfomycin, imipenem, and nitrofurantoin was observed. For K. pneumoniae, similar results were obtained, with discrepancies observed for gentamicin and nitrofurantoin. PFGE further identified eleven pulsotypes for E. coli and three clusters of K. pneumoniae. CTX-M-15 was detected in 85% of ESBL-producing E. coli and in 76% of ESBL-producing K. pneumoniae. In contrast, SHV-5 ESBL was identified in 17% of E. coli isolates and in 86% of K. pneumoniae isolates. The bla-TLA-1 gene was not detected in any of the 96 isolates analyzed. Overall, CTX-M-15 and SHV-5 were found to have a high rate of spread throughout the hospital and were associated with strong multidrug resistance.

Original languageEnglish
Pages (from-to)378-383
Number of pages6
JournalMicrobial Drug Resistance
Issue number5
Publication statusPublished - 1 Oct 2013

Bibliographical note

Copyright 2013 Elsevier B.V., All rights reserved.

All Science Journal Classification (ASJC) codes

  • Microbiology (medical)
  • Microbiology
  • Pharmacology
  • Immunology


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