Article
Distribution of superantigens in group A streptococcal isolates from Salvador, Brazil
Registro en:
BERMAN, H. F. et al. Distribution of superantigens in group A streptococcal isolates from Salvador, Brazil. BMC Infectious Diseases, v. 14, p. 294, 2014.
1471-2334
10.1186/1471-2334-14-294
Autor
Berman, Hillary F
Tartof, Sara Yee
Reis, Joice N
Reis, Mitermayer Galvão dos
Riley, Lee W
Resumen
Fogarty International Center, NIH, Grant number TW006563. Group A streptococcus (GAS) causes invasive disease, superficial disease, and can asymptomatically colonize humans. Superantigens are one virulence factor found in GAS. Previous studies found associations between the genes that encode superantigens and emm type of GAS. It is unknown if these associations are due to underlying biological factors that limit the distribution of superantigens or, alternatively, if these associations are due to the expansion of local GAS linages where these studies took place. To further address this question we screened GAS isolates collected from Salvador, Brazil for 11 known superantigen genes. Methods: Seventy-seven GAS isolates were screened by PCR for superantigen genes. These superantigen genes
were speA, speC, speG, speH, speI, speJ, speK, speL, speM, ssa, and smeZ. We used Fisher’s two-sided exact test to
identify associations between superantigens and GAS emm type. We then compared our results to previous reports
of superantigen prevalence and superantigen association with emm type.
Results: In our collection we found several emm type and superantigen genotype combinations that have
previously been reported in isolates from Europe and Australia. We also found that speA was significantly associated
with emm type 1, and that speC was significantly associated with emm type 12.
Conclusions: Our study reports superantigen genotypes of GAS from a region of the world that is lacking this
information. We found evidence of common GAS superantigen genotypes that are spread worldwide as well as
novel superantigen genotypes that, so far, are unique to Brazil.