BACKGROUND Group A Streptococcus (GAS) clinical and molecular epidemiology varies with location and time. These differences are not or are poorly understood. METHODS AND FINDINGS We prospectively studied the epidemiology of GAS infections among children in outpatient hospital clinics in Brussels (Belgium) and Brasília (Brazil). Clinical questionnaires were filled out and microbiological sampl...

The genetic diversity of group A streptococcal (GAS) isolates obtained in 1990 from Ethiopian children with various streptococcal diseases was studied by using emm gene sequence analysis. A total of 217 GAS isolates were included: 155 and 62 isolates from throat and skin, respectively. A total of 78 different emm/st types were detected among the 217 isolates. Of these, 166 (76.5%) belonged to 5...

BACKGROUND Group A Streptococcus (GAS)-related disease is responsible for high mortality and morbidity in the Pacific region. The high diversity of circulating strains in this region has hindered vaccine development due to apparently low vaccine coverage of type-specific vaccines. METHOD Prospective passive surveillance of all GAS isolates in New Caledonia was undertaken in 2012 using emm typ...

Molecular epidemiological data on Group A Streptococcus (GAS) infection in Africa is scarce. We characterized the emm-types and emm-clusters of 433 stored clinical GAS isolates from The Gambia collected between 2004 2018. To reduce potential for strain mistyping, we used a newly published primer emm-typing. There was considerable diversity, highlighting need vaccine development offering broad p...

A rapid PCR-enzyme-linked immunosorbent assay for identification of 10 important emm gene types of Streptococcus pyogenes was developed. The emm genotypes of a coded panel of strains of known M serotype were determined, and in 144 of 149 cases (97%) the results were congruous. Strains of types that were not included in the panel of capture probes were emm genotyped by sequencing.

Since the late 1980s several studies have described the increased incidence and severity of invasive group A streptococcal (GAS) infections. However, most studies on GAS pathogenesis have focused on information obtained during outbreaks. We analyzed isolate distribution and host susceptibility as part of a nationwide prospective surveillance study performed between January 2001 and August 2002....

Because of the allelic variations within the M protein gene (emm gene) of group A streptococci, reliable typing of this important human pathogen can be accomplished by the use of emm gene-specific oligonucleotide probes. Two technical modifications (a reverse dot blot and a reverse line blot hybridization assay) of a novel approach for the type-specific identification of emm genes have been dev...

Group A Streptococcus (GAS) is a human-adapted pathogen that causes a variety of diseases, including pharyngitis and invasive infections. GAS strains are categorized by variation in the nucleotide sequence of the gene (emm) that encodes the M protein. To identify the emm types of GAS strains causing pharyngitis in Ontario, Canada, we sequenced the hypervariable region of the emm gene in 4,635 p...

Stable maximum likelihood estimation (MLE) of item parameters in 3PLM with a modest sample size remains a challenge. The current study presents a mixture-modeling approach to 3PLM based on which a feasible Expectation-Maximization-Maximization (EMM) MLE algorithm is proposed. The simulation study indicates that EMM is comparable to the Bayesian EM in terms of bias and RMSE. EMM also produces sm...

A recent study by Bidet et al. (1) reported the molecular epidemiology of the streptococcal invasive locus (sil) in the group A streptococcus (GAS), an organism which caused invasive infections in French children. The authors demonstrated the prevalence of emm type toxin genotypes among 74 invasive GAS isolates from French children. The authors PCR amplified and characterized the locus DNA of s...