Vancomycin-resistant Staphylococcus aureus isolate from a patient in Pennsylvania - PubMed (original) (raw)

doi: 10.1128/AAC.48.1.275-280.2004.

Linda M Weigel, Peter C Appelbaum, Linda K McDougal, Jasmine Chaitram, Sigrid McAllister, Nancye Clark, George Killgore, Caroline M O'Hara, Laura Jevitt, Jean B Patel, Bülent Bozdogan

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Vancomycin-resistant Staphylococcus aureus isolate from a patient in Pennsylvania

Fred C Tenover et al. Antimicrob Agents Chemother. 2004 Jan.

Abstract

A vancomycin-resistant Staphylococcus aureus (VRSA) isolate was obtained from a patient in Pennsylvania in September 2002. Species identification was confirmed by standard biochemical tests and analysis of 16S ribosomal DNA, gyrA, and gyrB sequences; all of the results were consistent with the S. aureus identification. The MICs of a variety of antimicrobial agents were determined by broth microdilution and macrodilution methods following National Committee for Clinical Laboratory Standards (NCCLS) guidelines. The isolate was resistant to vancomycin (MIC = 32 micro g/ml), aminoglycosides, beta-lactams, fluoroquinolones, macrolides, and tetracycline, but it was susceptible to linezolid, minocycline, quinupristin-dalfopristin, rifampin, teicoplanin, and trimethoprim-sulfamethoxazole. The isolate, which was originally detected by using disk diffusion and a vancomycin agar screen plate, was vancomycin susceptible by automated susceptibility testing methods. Pulsed-field gel electrophoresis (PFGE) of SmaI-digested genomic DNA indicated that the isolate belonged to the USA100 lineage (also known as the New York/Japan clone), the most common staphylococcal PFGE type found in hospitals in the United States. The VRSA isolate contained two plasmids of 120 and 4 kb and was positive for mecA and vanA by PCR amplification. The vanA sequence was identical to the vanA sequence present in Tn1546. A DNA probe for vanA hybridized to the 120-kb plasmid. This is the second VRSA isolate reported in the United States.

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Figures

FIG. 1.

FIG. 1.

Disk diffusion and Etest analysis of the PA-VRSA isolate on Mueller-Hinton agar. A zone of complete growth inhibition can be observed within a wider zone of reduced growth around both the Etest strip and the 30-μg vancomycin disk. The arrows indicate the presence of small colonies within the inner zone of inhibition that impact the reading of the MIC result.

FIG. 2.

FIG. 2.

Time-kill studies with the PA-VRSA isolate and daptomycin. The organism was grown in the absence of drug (growth control), at the MIC (1x) for the organism, and at twice (2x) and four times (4x) the concentration of daptomycin required to inhibit the growth of the organism. The decrease in viable counts of >3 log units indicates that daptomycin is bactericidal for this organism.

FIG. 3.

FIG. 3.

Population analysis of the PA-VRSA isolate. Serial dilutions of the organism were plated on increasing concentrations of vancomycin. The PA-VRSA isolate was tested on two separate occasions (Run1 and Run2). S. aureus ATCC 29213 was used as a vancomycin-susceptible control. 1.00E+10, 1 × 1010.

FIG. 4.

FIG. 4.

PFGE of _Sma_I macrorestriction fragments of genomic DNA from the PA-VRSA (PA) and MI-VRSA (MI) strains. The _Sma_I macrorestriction fragments for the two VRSA isolates indicate that both are related to the USA100 pulsed-field type, also known as the New York/Japan clone.

References

    1. Arthur, M., C. Molinas, F. Depardieu, and P. Courvalin. 1993. Characterization of Tn_1546_, a Tn_3_-related transposon conferring glycopeptide resistance by synthesis of depsipeptide peptidoglycan precursors in Enterococcus faecium BM4147. J. Bacteriol. 175**:**117-127. -PMC -PubMed
    1. Bannerman, T. L. 2003. Staphylococcus, Micrococcus, and other catalase-positive cocci that grow aerobically, p. 384-404. In P. R. Murray, E. J. Baron, J. H. Jorgenson, M. A. Pfaller, and R. H. Yolken (ed.), Manual of clinical microbiology. ASM Press, Washington, D.C.
    1. Bannerman, T. L., G. A. Hancock, F. C. Tenover, and J. M. Miller. 1995. Pulsed-field electrophoresis as a replacement for bacteriophage typing of Staphylococcus aureus. J. Clin. Microbiol. 33**:**551-555. -PMC -PubMed
    1. Bismuth, R., R. Zilhao, H. Sakamoto, J. L. Guesdon, and P. Courvalin. 1990. Gene heterogeneity for tetracycline resistance in Staphylococcus spp. Antimicrob. Agents Chemother. 34**:**1611-1614. -PMC -PubMed
    1. Bugg, T. D. H., G. D. Wright, S. Dutka-Malen, M. Arthur, P. Courvalin, and C. T. Walsh. 1991. Molecular basis for vancomycin resistance in Enterococcus faecium BM4147: biosynthesis of a depsipeptide peptidoglycan precursor by vancomycin resistance proteins VanH and VanA. Biochemistry 30**:**10408-10415. -PubMed

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