High prevalence of blaCTX–M in Enterobacteriaceae isolates from the Kingdom of Bahrain

Abstract

Objective To determine the molecular epidemiology of extended-spectrum β-lactamase (ESBL) by testing a cohort of clinical ESBL-producing bacterial isolates that were isolated in the Kingdom of Bahrain. Methods ESBL producing Enterobacteriaceae isolates (based on phenotypic tests) were collected from Microbiology Laboratory of the Salmaniya Medical Complex, Bahrain between January-June 2006. Antibiotic susceptibility to a panel of antibiotics was performed and bla CTX-M genes were detected by multiplex PCR. Results A total of 230 isolates ( Escherichia coli, n=180; Klebsiella pneumoniae, n=50) were studied, 98% were CTX-M type. For Escherichia coli isolates, 65 (36.1%) harbored CTXM+TEM combination and 68 (37.8%) had CTX-M alone. In contrast, for Klebsiella pneumoniae isolates only 5 (10.0%) harbored the CTX-M combination, and none had CTX-M only. The bla CTX-M gene was found predominantly in urine isolates ( n=145/230; 63.0%). Sensitivity to imipenem and nitrofurantoin was 100% and 60%, respectively. CTX-M carriage was associated with the resistance to fluoroquinolones, trimethoprim-sulfamethoxazole and aminoglycosides. Conclusions Our study documentes high prevalence of CTX-M ESBL type among Escherichia coli and Klebsiella from the Kingdom of Bahrain. The apparent dissemination of CTX-M producers could represent a substantial barrier in the treatment of community-acquired infections. The use of extended-spectrum cephalosporins, quinolones, and aminoglycosides is compromised, leaving carbapenems as the therapeutic option for severe infections caused by ESBL producers.