Emergence of Ciprofloxacin-Nonsusceptible Streptococcus pyogenes Isolates from Healthy Children and Pediatric Patients in Portugal

We describe 66 ciprofloxacin-nonsusceptible Streptococcus pyogenes isolates recovered from colonized and infected children. The ParC S79A substitution was frequent and associated with the emm6/sequence type 382 (emm6/ST382) lineage. The ParC D83G substitution was detected in two isolates (emm5/ST99 and emm28/ST52 lineages). One isolate (emm89/ST101) had no quinolone resistance-determining region codon substitutions or other resistance mechanisms. Five of 66 isolates were levofloxacin resistant. Although fluoroquinolones are not used in children, they may be putative disseminators of fluoroquinolone-nonsusceptible strains in the community.