Cell Wall Thickening Is a Common Feature of Vancomycin Resistance in Staphylococcus aureus

• DOI: 10.1128/jcm.41.1.5-14.2003
• Publication Date: 2003-01-07T18:03:11Z
• Authors: Longzhu Cui; Xiaoxue Ma; Katsuhiro Sato; Keiko Okuma; Fred C. Tenover; Elsa M. Mamizuka; Curtis G. Gemmell; Mi-Na Kim; Marie-Cecile Ploy; N. El Solh; Vivian Ferraz; Keiichi Hiramatsu
• Keywords: Teicoplanin; Strain (injury)

ABSTRACT We have previously shown that a thickened cell wall is responsible for the vancomycin resistance of vancomycin-resistant Staphylococcus aureus (VRSA) (equivalent to vancomycin-intermediate S. and glycopeptide-intermediate ) strain Mu50 (L. Cui, H. Murakami, K. Kuwahara-Arai, Hanaki, Hiramatsu, Antimicrob. Agents Chemother. 44:2276-2285, 2000). However, mechanism in other VRSA strains remained unclear. In this study, 16 clinical from seven countries were subjected serial daily passage drug-free medium. After 10 84 days nonselective medium, passage-derived with decreased MICs (MIC, <4 mg/liter) obtained. all except one (15 16) still possessed subpopulations resistant as judged by population analysis, mutant selected one-step selection frequency 4.25 × −6 1.64 −3 . The data indicated cells are frequently generated even after selective pressure lifted. Cell thicknesses glycopeptides (vancomycin teicoplanin) beta-lactams (imipenem oxacillin) determined total 48 strains, including 15 sets three strains: strain, obtained strain. No simple correlation between glycopeptide beta-lactam was seen, while significant correlations teicoplanin ( r = 0.679; P < 0.001) imipenem oxacillin 0.787; recognized. Moreover, had significantly walls, which became thinner loss during passages again thick strains. showed thickness high two (correlation coefficients, 0.908 0.655 but not those antibiotics tested. These results together coupled changes isogenic indicate thickening common phenotype may be phenotypic determinant aureus.