High-Level Resistance to Gentamicin in Clinical Isolates of Enterococci

• Published in: The Journal of infectious diseases Vol. 147; no. 4; pp. 751 - 757
• Main Authors: Mederski-Samoraj, Barbara D., Murray, Barbara E.
• Format: Journal Article
• Language: English
• Published: United States The University of Chicago Press 01-04-1983; University of Chicago Press
• Subjects: Acetylation; Aminoglycosides; Aminoglycosides - pharmacology; Anti-Bacterial Agents - pharmacology; Antibiotics; Antimicrobial Therapeutics; Blood; Conjugation, Genetic; Drug Resistance, Microbial; Drug Synergism; Enterococcus faecalis; Enterococcus faecalis - drug effects; Enterococcus faecalis - enzymology; Enterococcus faecalis - genetics; Enzyme substrates; Enzymes; Gentamicins - pharmacology; Hospitals, University; Microbial Sensitivity Tests; Microbiology; Penicillin; R Factors; Synergism; Transferases - analysis; United States; United States
• ISSN: 0022-1899; 1537-6613
• DOI: 10.1093/infdis/147.4.751

Nine clinical isolates of Streptococcus faecalis from a university hospital were found to be resistant to high levels (minimal inhibitory concentration, >2,000 µg/ml) of gentamicin, tobramycin, amikacin, streptomycin, and kanamycin. The high-level resistance to these aminoglycosides and resistance to penicillin-aminoglycoside synergism were transferable by conjugation to a susceptible recipient strain. In three strains tested, the aminoglycoside resistance was mediated by four aminoglycoside-modifying enzymes: a 3′-phosphotransferase transferred from two strains, a 2″-phosphotransferase and a 6′-acetyltransferase transferred from all three strains, and a streptomycin adenylyltransferase transferred from two strains. This is the first report of the occurrence of high-level gentamicin resistance in enterococcal isolates from the United States.