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. 2000 Nov;44(11):3196-8.
doi: 10.1128/AAC.44.11.3196-3198.2000.

Resistance to multiple fluoroquinolones in a clinical isolate of Streptococcus pyogenes: identification of gyrA and parC and specification of point mutations associated with resistance

S S Yan  1 , M L Fox, S M Holland, F Stock, V J Gill, D P Fedorko
Affiliations

Resistance to multiple fluoroquinolones in a clinical isolate of Streptococcus pyogenes: identification of gyrA and parC and specification of point mutations associated with resistance

S S Yan et al. Antimicrob Agents Chemother. 2000 Nov.

Abstract

A strain of Streptococcus pyogenes resistant to multiple fluoroquinolones was isolated from the blood of an immunocompromised patient. Resistance to fluoroquinolones in S. pyogenes has not been previously studied. Compared to 10 sensitive strains of S. pyogenes, the fluoroquinolone-resistant clinical isolate of S. pyogenes presented point mutations in gyrA, predicting that serine-81 was changed to phenylalanine and that methionine-99 was changed to leucine, and in parC, predicting that serine-79 was changed to tyrosine. The mechanism of fluoroquinolone resistance in this isolate of S. pyogenes appears to be analogous to previously reported mechanisms for Streptococcus pneumoniae.

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Figures

FIG. 1
FIG. 1
Protein tree for the full-length gyrase A and ParC subunit of topoisomerase IV of several bacterial species. The protein sequences are from GenBank. The phylogenetic distance was determined using the unbalanced method provided by the computer program MegAlign. Lengths of branches correspond to sequence divergence. The scale underneath the tree represents the actual number of amino acid substitutions.
See this image and copyright information in PMC

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