Distribution of emm type and antibiotic susceptibility of group A streptococci causing invasive and noninvasive disease

Abstract

To determine the prevalence of macrolide antibiotic and levofloxacin resistance in infections with Streptococcus pyogenes (group A streptococcus or GAS), strains were collected from 45 medical institutions in various parts of Japan between October 2003 and September 2006. Four hundred and eighty-two strains from patients with GAS infections were characterized genetically. Strains were classified into four groups according to the type of infection: invasive infections (n574) including sepsis, cellulitis and toxic-shock-like syndrome; acute otitis media (AOM; n523); abscess (n553); and pharyngotonsillitis (n5332). Among all strains, 32 emm types were identified; emm1 was significantly more common in invasive infections (39.2 %) and AOM (43.5 %) than in abscesses (3.8 %) or pharyngotonsillitis (10.2 %). emm12 and emm4 each accounted for 23.5 % of pharyngotonsillitis cases. Susceptibility of GAS strains to eight b-lactam agents was excellent, with MICs of 0.0005-0.063 mg ml "1 . Macrolide-resistant strains accounted for 16.2 % of all strains, while the percentages of strains possessing the resistance genes erm(A), erm(B) and mef(A) were 2.5 %, 6.2 % and 7.5 %, respectively. Although no strains with high resistance to levofloxacin were found, strains with an MIC of 2-4 mg ml "1 (17.4 %) had amino acid substitutions at either Ser-79 or Asp-83 in ParC. These levofloxacin-intermediately resistant strains included 16 emm types, but macrolide-resistant strains were more likely than others to represent certain emm types.

Molecular emm genotyping and antibiotic susceptibility of Streptococcus dysgalactiae subsp. equisimilis isolated from invasive and non-invasive infections

“…ML and levofloxacin resistance rates of S. dysgalactiae subsp. equisimilis were the same as for GAS (Wajima et al, 2008), but different from those reported for GBS in Japan (Murayama et al, 2009). …”

“…Three ML resistance genes, erm(A) (Seppälä et al, 1998), erm(B) (Trieu-Cuot et al, 1990) and mef(A) (Clancy et al, 1996;Tait-Kamradt et al, 1997), were identified by PCR, as described previously (Wajima et al, 2008). Isolates with the erm(A) gene show an inducible ML/lincosamide/streptogramin B resistance phenotype, whilst strains with the erm(B) gene show a constitutive ML/ lincosamide/streptogramin B resistance phenotype arising from methylation of 23S rRNA.…”

“…The antimicrobials were obtained from pharmaceutical manufacturers. Four genes related to fluoroquinolone resistance, gyrA, gyrB, parC and parE, were analysed using four sets of primers as described previously (Wajima et al, 2008).…”

“…The antimicrobials were obtained from pharmaceutical manufacturers. Four genes related to fluoroquinolone resistance, gyrA, gyrB, parC and parE, were analysed using four sets of primers as described previously (Wajima et al, 2008).Genotyping of emm and bootstrap analysis. For emm genotyping by PCR, a primer set was used as described previously (Beall et al, 1996;Whatmore & Kehoe, 1994).…”

Severe Acute Otitis Media Caused by Mucoid<i> Streptococcus Pyogenes</i> in a Previously Healthy Adult

“…Macrolide resistance has gradually increased in S. pyogenes isolates around the world, including Japan (Wajima et al 2008;Arai et al 2011). Resistance of S. pyogenes to macrolides is mainly caused by two mechanisms: one involving 23S ribosomal RNA methylase genes (ermB and ermA) and the other involving the efflux determinant mefA (Sutcliffe et al 1996;Seppala et al 1998).…”