AMINOGLYCOSIDE MODIFYING ENZYMES DETECTED IN STRAINS OF ESCHERICHIA, KLEBSIELLA, PSEUDOMONAS AND ACINETOBACTER IMPLICATED IN INVASIVE INFECTIONS IN NAIROBI, KENYA

Abstract

Aminoglycoside resistance through the production of aminoglycoside modifying enzymes (AMEs) is common and thus of clinical importance. The presence of AMEs genes in gram-negative bacteria on plasmids, transposons and integrons facilitates the rapid acquisition of antibiotic resistance. This study aimed to characterize AMEs in antibiotic resistant strains of Escherichia, Klebsiella, Pseudomonas and Acinetobacter implicated in invasive infections in Nairobi, Kenya. The experimental design was a two point cross-sectional design comparing 54 clinical isolates obtained from the KEMRI laboratory collected in 2001 to 2006 and 54 clinical isolates from Aga Khan University Hospital collected in 2007 to 2008. The isolates were identified, tested for antimicrobial susceptibility to seven aminoglycosides then the AMEs were detected phenotypically and genotypically. The most prevalent AME gene detected was acc(6)-Ib-cr (45.9%) followed by acc(3)-II (25.9%, aac(6)-I(22.2%) and aac(3)-I (16.3%). Phenotypic studies showed that multidrug resistant Pseudomonas aeruginosa harboured numerous AMEs and 81% of the resistance was conferred by impermeability. Increase in aminoglycoside resistance by both naturally derived and semi synthetic antibiotics is alarming. Methods for monitoring their effectiveness should be instituted at the different healthcare system in Kenya.