High-level aminoglycoside resistance and beta-lactamase production in enterococci at a tertiary care hospital in India.
Enterococci, a family of important opportunistic pathogens, exhibits intrinsic resistance to a number of antimicrobial agents in addition to acquired multidrug resistance. The present study was conducted to determine whether enterococci at a tertiary care hospital in India exhibit high-level aminoglycoside resistance and beta-lactamase production. Enterococci were isolated from various clinical specimens and identified phenotypically. High-level resistance (HLR) to gentamicin, kanamycin, and streptomycin was determined by disc diffusion tests. Beta-lactamase production was detected using three methods: iodometric, acidometric, and chromogenic beta-lactamase assays. Among the 86 enterococci isolated, 34 were found to have HLR to one or more aminoglycosides; HLR to kanamycin was most common. Vancomycin resistance was present in four of the isolates. Only one enterococcus produced beta-lactamase, and it was sensitive to ampicillin on routine disc diffusion testing. Beta-lactamase production among enterococci, though not very common, may be missed on routine susceptibility testing. Frequent occurrence of HLR to kanamycin makes amikacin a poor choice for inclusion in combination therapy with cell wall-active agents.
Agarwal
Jyotsna
J
Department of Microbiology, CSM Medical University, Lucknow, India. jyotsna_govil@yahoo.com
Kalyan
Rajkumar
R
Singh
Mastan
M
D000617:Aminoglycosides / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000096:biosynthesis; D024881:Drug Resistance, Bacterial; D016983:Enterococcus / Q000187:drug effects* / Q000302:isolation & purification; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology*; D006761:Hospitals; D006801:Humans; D007194:India; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000096:biosynthesis*; D047090:beta-Lactams / Q000494:pharmacology*
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D047090:beta-Lactams; D001618:beta-Lactamases