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 β-lactamases (ESBL)-producing Enterobacteriaecae among patients in the United Arab Emirates. Materials and Methods: A total of 130 Enterobacteriaceaecomprising 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 μg/ml), cefotetan (MIC 32 μg/ml) and piperacillin/tazobactam (MIC 32 μg/ml). MIC for the carbapenems was lower in non-ESBL isolates (0.034 μg/ml) than ESBL isolates (0.071 μg/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.