Objective: Several mechanisms account for carbapenem resistance in Pseudomonas (P.) aeruginosa which is an emerging problem at a tertiary care hospital (TCH) in Jamaica. The observed pattern of carbapenem resistance that results from efflux mechanisms is unique because it is specific to meropenem (MEM). Investigation of efflux as a mechanism of carbapenem resistance needed to be done as the information obtained could inform therapeutic and infection control strategies.
Methodology: At the Microbiology Laboratory of a TCH in Jamaica, from May 2009 to March 2011, of 105 MDR Gram negative bacilli isolated from clinical specimen submitted for routine identification and susceptibility testing, all the MEM resistant Pseudomonas aeruginosa isolates (10) were selected. They were tested for efflux using the efflux inhibitor PABN in a method described by Giske et al in 2008.
Results: This study detected evidence of meropenem efflux in 80% of meropenem-resistant Pseudomonas aeruginosa implicated in nosocomial infections in a Jamaican hospital using the phenyl-arginine-β-naphthylamide inhibition assay. Meropenem-efflux-positive isolates belonged to two unrelated chromosomal lineages.
Conclusion: These results underscored the ned for improved surveillance and control to prevent this mechanism emerging in further P. aeruginosa strains