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Streptococcus pyogenes strains in Sao Paulo, Brazil: molecular characterization as a basis for StreptInCor coverage capacity analysis.

Freschi de Barros S, De Amicis KM, Alencar R, Smeesters PR, Trunkel A, Postól E, Almeida Junior JN, Rossi F, Pignatari AC, Kalil J, Guilherme L - BMC Infect. Dis. (2015)

Bottom Line: The emm-pattern and tissue tropism for these M types were also predicted and compared based on the emm-cluster classification.This is the first report of S. pyogenes strain characterization in Sao Paulo, one of the largest cities in the world; thus, the strain panel described here is a representative sample for vaccine coverage capacity analysis.Our results enabled evaluation of StreptInCor candidate vaccine coverage capacity against diverse M-types, indicating that the vaccine candidate likely would induce protection against the diverse strains worldwide.

View Article: PubMed Central - PubMed

Affiliation: Heart Institute (InCor), School of Medicine, University of Sao Paulo, Sao Paulo, 01246-000, Brazil. sfreschi@usp.br.

ABSTRACT

Background: Several human diseases are caused by Streptococcus pyogenes, ranging from common infections to autoimmunity. Characterization of the most prevalent strains worldwide is a useful tool for evaluating the coverage capacity of vaccines under development. In this study, a collection of S. pyogenes strains from Sao Paulo, Brazil, was analyzed to describe the diversity of strains and assess the vaccine coverage capacity of StreptInCor.

Methods: Molecular epidemiology of S. pyogenes strains was performed by emm-genotyping the 229 isolates from different clinical sites, and PCR was used for superantigen profile analysis. The emm-pattern and tissue tropism for these M types were also predicted and compared based on the emm-cluster classification.

Results: The strains were fit into 12 different emm-clusters, revealing a diverse phylogenetic origin and, consequently, different mechanisms of infection and escape of the host immune system. Forty-eight emm-types were distinguished in 229 samples, and the 10 most frequently observed types accounted for 69 % of all isolates, indicating a diverse profile of circulating strains comparable to other countries under development. A similar proportion of E and A-C emm-patterns were observed, whereas pattern D was less frequent, indicating that the strains of this collection primarily had a tissue tropism for the throat. In silico analysis of the coverage capacity of StreptInCor, an M protein-conserved regionally based vaccine candidate developed by our group, had a range of 94.5 % to 59.7 %, with a mean of 71.0 % identity between the vaccine antigen and the predicted amino acid sequence of the emm-types included here.

Conclusions: This is the first report of S. pyogenes strain characterization in Sao Paulo, one of the largest cities in the world; thus, the strain panel described here is a representative sample for vaccine coverage capacity analysis. Our results enabled evaluation of StreptInCor candidate vaccine coverage capacity against diverse M-types, indicating that the vaccine candidate likely would induce protection against the diverse strains worldwide.

No MeSH data available.


Related in: MedlinePlus

Frequency of emm-types. A total of 48 emm-types were represented in the collection. Abbreviation: GAS, group A streptococcus
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Fig1: Frequency of emm-types. A total of 48 emm-types were represented in the collection. Abbreviation: GAS, group A streptococcus

Mentions: The distribution of emm-types among the 229 GAS isolates is described in Table 1. The clinical origin was known for 214 isolates. Most samples were associated with invasive infection (n = 123, 57 %), whereas the remaining samples were recovered from throat (n = 57, 27 %) and skin infections (n = 34, 16% ). Forty-eight different emm-types were identified. The most frequent emm-types were emm1 (22 %), emm87 (8 %), emm22 (7 %), emm12 (7 %), emm77 (6 % ), emm6 (6 % ), emm89 (5 %), emm33 (3 %), emm75 (3 %) and emm3 (3 %) (Fig. 1). Taken together, these emm-types accounted for 69 % of the GAS isolates. To better understand the strain diversity present in our study, and its likely consequence for multivalent vaccine coverage, we have calculated the reciprocal Simpson index of diversity which results was 12.7 (95 % CI, 10.1-17.0).Table 1


Streptococcus pyogenes strains in Sao Paulo, Brazil: molecular characterization as a basis for StreptInCor coverage capacity analysis.

Freschi de Barros S, De Amicis KM, Alencar R, Smeesters PR, Trunkel A, Postól E, Almeida Junior JN, Rossi F, Pignatari AC, Kalil J, Guilherme L - BMC Infect. Dis. (2015)

Frequency of emm-types. A total of 48 emm-types were represented in the collection. Abbreviation: GAS, group A streptococcus
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4525746&req=5

Fig1: Frequency of emm-types. A total of 48 emm-types were represented in the collection. Abbreviation: GAS, group A streptococcus
Mentions: The distribution of emm-types among the 229 GAS isolates is described in Table 1. The clinical origin was known for 214 isolates. Most samples were associated with invasive infection (n = 123, 57 %), whereas the remaining samples were recovered from throat (n = 57, 27 %) and skin infections (n = 34, 16% ). Forty-eight different emm-types were identified. The most frequent emm-types were emm1 (22 %), emm87 (8 %), emm22 (7 %), emm12 (7 %), emm77 (6 % ), emm6 (6 % ), emm89 (5 %), emm33 (3 %), emm75 (3 %) and emm3 (3 %) (Fig. 1). Taken together, these emm-types accounted for 69 % of the GAS isolates. To better understand the strain diversity present in our study, and its likely consequence for multivalent vaccine coverage, we have calculated the reciprocal Simpson index of diversity which results was 12.7 (95 % CI, 10.1-17.0).Table 1

Bottom Line: The emm-pattern and tissue tropism for these M types were also predicted and compared based on the emm-cluster classification.This is the first report of S. pyogenes strain characterization in Sao Paulo, one of the largest cities in the world; thus, the strain panel described here is a representative sample for vaccine coverage capacity analysis.Our results enabled evaluation of StreptInCor candidate vaccine coverage capacity against diverse M-types, indicating that the vaccine candidate likely would induce protection against the diverse strains worldwide.

View Article: PubMed Central - PubMed

Affiliation: Heart Institute (InCor), School of Medicine, University of Sao Paulo, Sao Paulo, 01246-000, Brazil. sfreschi@usp.br.

ABSTRACT

Background: Several human diseases are caused by Streptococcus pyogenes, ranging from common infections to autoimmunity. Characterization of the most prevalent strains worldwide is a useful tool for evaluating the coverage capacity of vaccines under development. In this study, a collection of S. pyogenes strains from Sao Paulo, Brazil, was analyzed to describe the diversity of strains and assess the vaccine coverage capacity of StreptInCor.

Methods: Molecular epidemiology of S. pyogenes strains was performed by emm-genotyping the 229 isolates from different clinical sites, and PCR was used for superantigen profile analysis. The emm-pattern and tissue tropism for these M types were also predicted and compared based on the emm-cluster classification.

Results: The strains were fit into 12 different emm-clusters, revealing a diverse phylogenetic origin and, consequently, different mechanisms of infection and escape of the host immune system. Forty-eight emm-types were distinguished in 229 samples, and the 10 most frequently observed types accounted for 69 % of all isolates, indicating a diverse profile of circulating strains comparable to other countries under development. A similar proportion of E and A-C emm-patterns were observed, whereas pattern D was less frequent, indicating that the strains of this collection primarily had a tissue tropism for the throat. In silico analysis of the coverage capacity of StreptInCor, an M protein-conserved regionally based vaccine candidate developed by our group, had a range of 94.5 % to 59.7 %, with a mean of 71.0 % identity between the vaccine antigen and the predicted amino acid sequence of the emm-types included here.

Conclusions: This is the first report of S. pyogenes strain characterization in Sao Paulo, one of the largest cities in the world; thus, the strain panel described here is a representative sample for vaccine coverage capacity analysis. Our results enabled evaluation of StreptInCor candidate vaccine coverage capacity against diverse M-types, indicating that the vaccine candidate likely would induce protection against the diverse strains worldwide.

No MeSH data available.


Related in: MedlinePlus