Evolution of aminoglycoside resistance phenotypes of four Gram-negative bacteria: an 8-year survey in a University Hospital in Greece (original) (raw)

2003, International Journal of Antimicrobial Agents

In order to determine the resistance patterns and evolution trends of four common Enterobacteriaceae (Escherichia coli , Proteus spp., Klebsiella spp. and Enterobacter spp.), aminoglycoside resistance phenotypes of 8917 non-repetitive strains, isolated over an 8year period, were analysed. Phenotypes were defined by examining the susceptibility of the strains to a panel of aminoglycosides, using disk diffusion method. A large diversity of different resistance phenotypes was encountered. A significant progressive increase in the proportions of wild-type E. coli strains was noted. Among resistant strains of Enterobacter spp. and Klebsiella spp., the incidence of phenotype KTANt (kanamycin, tobramycin, amikacin and netilmicin), indicative of AAC(6?)-I production, was very high (66.7 and 46.5%, respectively). Phenotypes indicative for gentamicin-modifying enzymes as well as broad-spectrum combinations (combinations of gentamicin-modifying enzymes with AAC(6?)-I) were infrequent. #