Resistance to bacitracin in Streptococcus pyogenes from oropharyngeal colonization and noninvasive infections in Portugal was caused by two clones of distinct virulence genotypes

FEMS Microbiol Lett. 2009 Jun;296(2):235-40. doi: 10.1111/j.1574-6968.2009.01642.x. Epub 2009 May 6.

Abstract

During 2000-2007 in Lisbon, we identified 45 bacitracin-resistant Streptococcus pyogenes isolates among 1629 isolates: 24 from oropharyngeal healthy carriers (out of 1026), 21 from patients with noninvasive infections (out of 559) and zero from invasive infections (out of 44). Forty-four of those isolates, mainly of colonization, are low-level bacitracin-resistant members of the cMLS(B)-macrolide-resistant and tetracycline-susceptible emm28/ST52 clone previously detected in Europe, but only among clinical samples. One high-level bacitracin-resistant isolate, associated with a tonsillitis/pharyngitis episode, is cMLS(B)-macrolide-resistant and tetracycline-resistant member of the emm74/ST120 lineage, which was not previously known to include bacitracin-resistant isolates. The bcrABDR operon encoding an ATP-binding cassette transporter in Enterococcus faecalis was not detected among these bacitracin-resistant S. pyogenes strains. Virulence profiling indicated that genes coding for exotoxins and superantigens seem to be clone specific. This study provides an increased knowledge about specific bacitracin-resistant S. pyogenes strains, which may be useful in future investigations aiming to understand the mechanism(s) leading to bacitracin resistance and the cause(s) for differences in colonization and/or dissemination potential.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Bacitracin / pharmacology*
  • Bacterial Proteins / genetics
  • Bacterial Typing Techniques*
  • Carrier State / microbiology
  • Cluster Analysis
  • DNA Fingerprinting
  • Drug Resistance, Bacterial*
  • Electrophoresis, Gel, Pulsed-Field
  • Genotype
  • Humans
  • Lincosamides / pharmacology
  • Macrolides / pharmacology
  • Oropharynx / microbiology*
  • Pharyngitis / microbiology
  • Portugal
  • Streptococcal Infections / microbiology*
  • Streptococcus pyogenes / classification*
  • Streptococcus pyogenes / drug effects*
  • Streptococcus pyogenes / genetics
  • Streptococcus pyogenes / isolation & purification
  • Streptogramin B / pharmacology
  • Tonsillitis / microbiology
  • Virulence Factors / genetics

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Lincosamides
  • Macrolides
  • Virulence Factors
  • Bacitracin
  • Streptogramin B