Epidemiological analysis of Streptococcus pyogenes infections in Hong Kong.
OBJECTIVE
The aim of this study was to characterise clinical and microbiological features of isolates obtained from both invasive and non-invasive Streptococcus pyogenes infections in Hong Kong, between October 2005 and April 2008.


METHODS
Clinical data of invasive isolates were collected retrospectively. Altogether 281 isolates were emm sequence typed and tested for antimicrobial susceptibility using disk diffusion method. Detection of the presence of the streptococcal pyrogenic exotoxin genes was also carried out.


RESULTS
emm1, emm4 and emm12 were the most prevalent in both the invasive and non-invasive groups with an increase in incidence of emm22 compared with a previous study. emm22 was associated with invasive cellulitis and wound infection. The overall rate of erythromycin resistance was 25.6% and was significantly higher in emm22 strains (85.7%). The phage-encoded superantigen gene speA was exclusively associated with emm1 in both invasive and non-invasive isolates.


CONCLUSIONS
This study revealed a changing epidemiology of S. pyogenes infection in Hong Kong, with a unique pattern compared with other Asian countries. Invasiveness is not related to the presence of speA, speC or ssa genes and the antimicrobial resistance rate was high for macrolides. The findings have an implication on the use and efficacy of the polyvalent S. pyogenes vaccine under development.
Chan
Janice C K
JC
Microbiology Division, Public Health Laboratory Services Branch, Centre for Health Protection, Department of Health, Hong Kong SAR, China. mo_phls7@dh.gov.hk
Chu
Yiu-Wai
YW
Chu
Man-Yu
MY
Cheung
Terence K M
TK
Lo
Janice Y C
JY
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000187:drug effects / Q000235:genetics*; D004917:Erythromycin / Q000494:pharmacology; D005098:Exotoxins / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D012189:Retrospective Studies; D013290:Streptococcal Infections / Q000097:blood / Q000453:epidemiology* / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000235:genetics / Q000302:isolation & purification*; D018089:Superantigens / Q000235:genetics
D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D005098:Exotoxins; D008565:Membrane Proteins; C117980:SpeA protein, Streptococcus pyogenes; D018089:Superantigens; D004917:Erythromycin