Resistance to bacitracin in Streptococcus pyogenes from oropharyngeal colonization and noninvasive infections in Portugal was caused by two clones of distinct virulence genotypes.
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.
Pires
Renato
R
Centro de Recursos Microbiológicos, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.
Rolo
Dora
D
Mato
Rosario
R
Feio de Almeida
João
J
Johansson
Christina
C
Henriques-Normark
Birgitta
B
Morais
Ana
A
Brito-Avô
António
A
Gonçalo-Marques
José
J
Santos-Sanches
Ilda
I
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001414:Bacitracin / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D002353:Carrier State / Q000382:microbiology; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D006801:Humans; D055231:Lincosamides / Q000494:pharmacology; D018942:Macrolides / Q000494:pharmacology; D009960:Oropharynx / Q000382:microbiology*; D010612:Pharyngitis / Q000382:microbiology; D011174:Portugal; D013290:Streptococcal Infections / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D025381:Streptogramin B / Q000494:pharmacology; D014069:Tonsillitis / Q000382:microbiology; D037521:Virulence Factors / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D055231:Lincosamides; D018942:Macrolides; D037521:Virulence Factors; D001414:Bacitracin; D025381:Streptogramin B