Inducible Resistance to Vancomycin in Enterococcus faecium D366

Strain D366, a clinical isolate of Enterococcus faecium, is resistant (minimum inhibitory concentration [MIC] 32 mg/L) to vancomycin. When exponential-phase cultures were exposed to half the MIC of vancomycin, a lag of 3—4 h occurred before growth resumed. Cells preexposed to ½ MICs of vancomycin di...

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Bibliographic Details
Published in:The Journal of infectious diseases 1989-06, Vol.159 (6), p.1095-1104
Main Authors: Williamson, Russell, Al-Obeid, Suleiman, Shlaes, Janet H., Goldstein, Fred W., Shlaes, David M.
Format: Article
Language:English
Subjects:
Aged
Aged, 80 and over
Antibacterial agents
Antibiotics
Antibiotics. Antiinfectious agents. Antiparasitic agents
Bacteriolysis - drug effects
Biological and medical sciences
Cell growth
Cell membranes
Cell walls
Chromatography, Affinity
Colony Count, Microbial
Drug Resistance, Microbial
Enterococcus faecium
Female
Gels
Glycopeptides
Glycopeptides - metabolism
Glycopeptides - pharmacology
Humans
Medical sciences
Membrane Glycoproteins - biosynthesis
Microbial sensitivity tests
Microscopy, Electron
Original Articles
Penicillin
Peptidoglycan - biosynthesis
Peptidoglycan - metabolism
Pharmacology. Drug treatments
Streptococcus - drug effects
Streptococcus - growth & development
Streptococcus - ultrastructure
Vancomycin - pharmacology
Vancomycin resistance
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Description
Summary:Strain D366, a clinical isolate of Enterococcus faecium, is resistant (minimum inhibitory concentration [MIC] 32 mg/L) to vancomycin. When exponential-phase cultures were exposed to half the MIC of vancomycin, a lag of 3—4 h occurred before growth resumed. Cells preexposed to ½ MICs of vancomycin did not show any lag. Pregrowth of D366 with vancomycin caused resistance to all glycopeptides tested. Pregrowth in vancomycin resulted in synthesis of a 3.95-kDa cytoplasmic-membrane-associated protein. This protein was correlated with resistance in mutants with high-level resistance, in the presence of NaCl, which inhibited the activity of vancomycin, and when several glycopeptides with varying activities were tested. Vancomycin-grown cells appeared abnormal and lysed at a much slower rate than did normal cells. We conclude that (1) vancomycin resistance in D366 is inducible; (2) resistance is correlated with the synthesis of a 39.5-kDa cytoplasmic membrane protein; and (3) this protein may play an additional role in the inhibition of normal lytic functions.
ISSN:0022-1899
1537-6613
DOI:10.1093/infdis/159.6.1095