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Alterations of Cell Wall Structure and MetabolismAccompany Reduced Susceptibility to Vancomycin in an IsogenicSeries of Clinical Isolates of Staphylococcusaureus

Year: 2003

Type: article

Abstract: A series of isogenic methicillin-resistant Staphylococcus aureus isolates recovered from a bacteremic patient were shown to acquire gradually increasing levels of resistance to vancomycin during chemotherapy with the drug (K. Sieradzki, T. Leski, L. Borio, J. Dick, and A. Tomasz, J. Clin. Microbiol. 41:1687-1693, 2003). We compared properties of the earliest (parental) vancomycin-susceptible isolate, JH1 (MIC, 1 microg/ml), to two late (progeny) isolates, JH9 and JH14 (vancomycin MIC, 8 microg/ml). The resistant isolates produced abnormally thick cell walls and poorly separated cells when grown in antibiotic-free medium. Chemical analysis of the resistant isolates showed decreased cross-linkage of the peptidoglycan and drastically reduced levels of PBP4 as determined by the fluorographic assay. Resistant isolates showed reduced rates of cell wall turnover and autolysis. In vitro hydrolysis of resistant cell walls by autolytic extracts prepared from either susceptible or resistant strains was also slow, and this abnormality could be traced to a quantitative (or qualitative) change in the wall teichoic acid component of resistant isolates. Some change in the structure and/or metabolism of teichoic acids appears to be an important component of the mechanism of decreased susceptibility to vancomycin in S. aureus.

Source: Journal of Bacteriology

DOI: 10.1128/jb.185.24.7103-7110.2003

Authors: K. Sieradzki, A. Tomasz

Institution: Rockefeller University

Language: English

Topic: Antimicrobial Resistance in Staphylococcus

Subfield: Infectious Diseases

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: green

Funders: U.S. Public Health Service, National Institute of Allergy and Infectious Diseases