[Antimicrobial sensitivity and characterization of Streptococcus pyogenes strains isoleated from a scarlatina outbreak].
OBJECTIVE
To evaluate the in vitro activities of 13 antimicrobial agents against 47 group A Streptococcus pyogenes (GAS) strains, and to determine the presence of genes encoding streptococcal pyrogenic exotoxin A (SpeA) and the M-protein serotypes.


METHODS
A cross-sectional study was conducted at Centro de Salud Dr. José Castro Villagrana, during a scarlet fever outbreak occurring between December 1999 and January 2000, among 137 children at Colegio Espíritu de América. Minimum Inhibitory Concentrations (MICs) were obtained by the semiautomated microdilution method. Automated DNA sequencing was used for analysis of sequence variation in genes encoding the M protein, and SpeA.


RESULTS
All strains were sensitive to betalactams and clindamycin. Six (12.7%) were resistant to erythromycin. The M2 type was the most frequently isolated GAS (27); almost all (96%) bacteria with the SpeA gene had the gene encoding the M2 protein.


CONCLUSIONS
The recent resurgence of GAS infections calls for molecular epidemiology research and studies on the sensitivity to macrolides and beta-lactams.
González Pedraza-Avilés
Alberto
A
Centro de Salud, Doctor José Castro-Villagrana, Servicios de Salud Pública del Distrito Federal, México, D.F., México.
Ortiz-Zaragoza
Catalina
C
Mota-Vázquez
Ricardo
R
Dickinson-Bannack
Ma Eloísa
ME
Dávila-Mendoza
Rocío
R
Fernández-Ortega
Miguel Angel
MA
D000293:Adolescent; D001426:Bacterial Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D016358:Contact Tracing; D004269:DNA, Bacterial / Q000235:genetics; D004196:Disease Outbreaks; D004351:Drug Resistance; D024901:Drug Resistance, Multiple, Bacterial; D005098:Exotoxins / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D008800:Mexico / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D010614:Pharynx / Q000382:microbiology; D012541:Scarlet Fever / Q000453:epidemiology / Q000382:microbiology*; D012574:Schools; D012703:Serotyping; D013297:Streptococcus pyogenes / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D005098:Exotoxins; D008565:Membrane Proteins; C117980:SpeA protein, Streptococcus pyogenes