Intrinsic reduced susceptibility of serotype 6 Streptococcus pyogenes to fluoroquinolone antibiotics.
J Infect Dis
; 191(8): 1272-9, 2005 Apr 15.
Article
em En
| MEDLINE
| ID: mdl-15776373
ABSTRACT
BACKGROUND:
Fluoroquinolone resistance is common in Staphylococcus aureus, is increasing in Streptococcus pneumoniae, and is reported in Streptococcus pyogenes.METHODS:
We surveyed 384 clinical isolates of S. pyogenes, isolated during 2002-2003, for susceptibility to ciprofloxacin. We performed nucleotide sequencing of the parC and gyrA genes and determined the M/emm type for selected isolates. Additionally, we analyzed M/emm type 6 S. pyogenes isolated during 1918-2003 from diverse locations.RESULTS:
Of the survey isolates, 10.9% had reduced zones of inhibition to ciprofloxacin in the disk-diffusion test and had elevated minimum inhibitory concentrations to other fluoroquinolones, compared with those of fully susceptible isolates. Of the resistant isolates, 90.5% were M/emm type 6, and all sequenced M/emm type 6 isolates contained a serine-to-alanine substitution at position 79 in parC. Strikingly, the same findings were also present in macrolide-resistant isolates from a recent outbreak of S. pyogenes infection in Pittsburgh and in the Lancefield reference strain of M type 6, which was isolated in 1918, decades before the development of fluoroquinolone antibiotics.CONCLUSION:
M/emm type 6 S. pyogenes has intrinsic reduced susceptibility to fluoroquinolones, as a result of a polymorphism in parC. This finding was also demonstrated in erythromycin-resistant M/emm type 6 S. pyogenes, which raises concern for the emergence of multidrug-resistant S. pyogenes.
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Base de dados:
MEDLINE
Assunto principal:
Streptococcus pyogenes
/
Fluoroquinolonas
/
Farmacorresistência Bacteriana
/
Antibacterianos
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Estados Unidos