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

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. 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. 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. 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.