Antimicrobial Susceptibility and Distribution of TEM and CTX-M Genes among ESBL-producing Klebsiella pneumoniae and Pseudomonas aeruginosa Causing Urinary Tract Infections

Background: Extended spectrum beta lactamases (ESBLs) have been observed in nearly all the species of family Enterobacteriaceae. The enzymes are plasmid mediated and are derived from broad-spectrum beta lactamase TEM and CTX- M by a limited number of mutations. This study was undertaken to characterize ESBL producers among Klebsiella pneumoniae and Pseudomonas aeruginosa by PCR, which were initially screened by phenotypic method.

Materials and Methods: A cross-sectional study was performed to evaluate 180 strains (30 K. pneumoniae and 150 P. aeruginosa) isolated from urine culture of hospitalized patients (Amir Al-Momenin Hospital, Zabol, south-eastern Iran) suffered from urinary tract infections during a period of six months. The prevalence of ESBL producing K. pneumoniae and P. aeruginosa was evaluated by disk diffusion test and polymerase chain reaction (PCR) by detecting TEM and CTX-M gene.

Results: The results of the study revealed that the prevalence of ESBL producing P. aeruginosa and K. pneumoniae by disk diffusion test was 13.3% for P. aeruginosa and 66.6% for K. pneumoniae. Seventy five percent and 65% of K. pneumoniae harboured the gene TEM and CTX-M, respectively. Forty five percent of P. aeruginosa isolates harboured the gene TEM but none of them demonstrated the gene CTX-M using PCR method.

Conclusion: ESBL producing P. aeruginosa and K. pneumoniae isolates showed a high prevalence in this study. Therefore it seems that continuous surveillance is essential to monitor the ESBLs producing microorganisms in hospitals and community.