Extended spectrum beta [beta]- lactamases in clinical isolates of gram-negative bacilli in Ajman, United Arab Emirates

ABSTRACT

Extended spectrum beta lactamas [ESBL] producing strains of Enterobacteriaceae and Pseudomonas spp. have emerged as a major problem worldwide. ESBLs represent a major group of beta-lactamases along with inducible AmpC beta lactamases and derepressed mutants. Many clinical laboratories test Gram-negative bacilli for ESBL production. However there is scarcity of information from United Arab Emirates [UAE]. This study was conducted to estimate the frequency of ESBLs and to detect different mechanisms of beta-lactam resistance [ESBLs, AmpC beta lactamases; both inducible and hyperproducers] in Gram-negative baeilli in Ajman, UAE. A total of 123 isolates of Gram-negative baeilli were tested for ESBL production and the Novel method was used to detect the above mechanisms of resistance. Of the 123 isolates, 48 [39%] were ESBL producers of which 36 [29.3%] were also derepressed mutants while remaining 12 [9.8%] were plain ESBL producers. Nine [7.3%] were plan derepressed mutants. Inducible AmpC beta-lactamase production was detected only in Pseudomonas aeruginosa [3.3%]. The commonest ESBL producers were E.coli [60.4%] and Klebsiella spp. [20.9%] but the most frequent ESBL producer was Klebsiella spp. [40%]. Forty one percent of ESBL producers were isolated from urine. The antimicrobial susceptibility test showed that 80% were resistant to Aztreonam. All the ESBL producing as well as derepressed mutants were sensitive to Imipenem. The occurrence of high frequency of ESBL-producing Gram-negative bacilli in our hospital is alarming and hence the need for urgent action to detect ESBL production along with continued surveillance, judicious use of antimicrobial agents as well as implementation of infection control measures: