Prevalence and antimicrobial susceptibility pattern of extended-spectrum beta-lactamase-producing Enterobacteriaceae in the United Arab Emirates.

OBJECTIVE

To investigate the prevalence and antibiotic susceptibility pattern of extended-spectrum beta-lactamases (ESBL)-producing Enterobacteriaceae among patients in the United Arab Emirates.

MATERIALS AND METHODS

A total of 130 Enterobacteriaceae comprising of Escherichia coli (n = 83), Klebsiella pneumoniae (n = 45) and Klebsiella oxytoca (n = 2) was studied. Of these 130 isolates, 64 were from urine. ESBL screening was by disc diffusion and confirmatory tests for ESBL phenotype were conducted using BD Phoenix ESBL System and cephalosporin/clavulanate combination discs. Susceptibility to a panel of antibiotics was evaluated.

RESULTS

Of the 130 isolates, 53 (41%) were identified as having ESBL phenotype; of these, 32 (60%) were E. coli, 20 (36%) K. pneumoniae and 2 (4%) K. oxytoca. ESBL phenotype was seen in 100% of endotracheal tubes isolates, 20 (31%) from urine, 7 (58%) from blood and 4 (80%) from catheter tips. Amikacin susceptibility was 100%. Over 90% of ESBL isolates showed resistance to aztreonam and cephalosporins. All Klebsiella isolates were carbapenem sensitive. One ESBL isolate showed intermediate resistance to imipenem and meropenem (both MIC 8 microg/ml), cefotetan (MIC 32 microg/ml) and piperacillin/tazobactam (MIC 32 microg/ml). MIC for the carbapenems was lower in non-ESBL isolates (0.034 microg/ml) than ESBL isolates (0.071 microg/ml). Resistance to gentamicin, ciprofloxacin and piperacillin/tazobactam was higher in ESBL than non-ESBL isolates (p < 0.05).

CONCLUSION

A high prevalence of ESBL-producing bacteria exists among in-patients in the United Arab Emirates. Amikacin and carbapenems remain the most effective drugs, but the presence of carbapenem-resistant ESBL-producing E. coli and occurrence of multidrug resistance are of concern. Continued surveillance and judicious antibiotic usage are recommended.