Occurrence of Extended-Spectrum Beta-Lactamase-Producing Pseudomonas aeruginosa Strains in South-West Nigeria

Extended-spectrum beta-lactamase production has been reported as one of the mechanisms that contribute to acquired beta-lactam resistance in Pseudomonas aeruginosa. This study investigated ESBL production among clinical isolates of P. aeruginosa in the institution and their susceptibility to antimicrobials. Ninety clinical isolates of P. aeruginosa were screened for ESBL production using the double-disc synergy test at the Department of Medical Microbiology Laboratory of University College Hospital, Ibadan, Nigeria between June 2010 and July 2011. The susceptibilities of the ESBL producers were determined against various classes of antibiotics. Rate of ESBL production was found to be 22.2%. ESBL production was found only in isolates from sputum (40%) and urine (60%). Susceptibility of the ESBL-producing P. aeruginosa strains to imipenem, meropenem and amikacin was 100% each while susceptibility to ciprofloxacin and gntamycin were 50 and 30%, respectively. Activities of ceftriaxone, ceftazidime and cefepime against P. aeruginosa were 0, 50 and 40%, respectively. In conclusion, this study has demonstrated ESBL-producing P. aeruginosa strains in this environment. Efforts should therefore be made to detect them. Clinicians should consider ESBL production as a possibility in treatment failure with beta-lactam antibiotics.