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Group A streptococcal genotypes from pediatric throat isolates in Rome, Italy
G Dicuonzo1, G Gherardi, G Lorino
1Department of Medicine and Microbiology, Università Campus Bio-Medico, Rome, Italy.
Abstract:
In a study assessing genetic diversity, 114 group A streptococcus (GAS) isolates were recovered from pediatric pharyngitis patients in Rome, Italy. These isolates comprised 22 different M protein gene (emm) sequence types, 14 of which were associated with a distinct serum opacity factor/fibronectin binding protein gene (sof) sequence type. Isolates with the same emm gene sequence type generally shared a highly conserved chromosomal macrorestriction profile. In three instances, isolates with dissimilar macrorestriction profiles had identical emm types; in each of these cases multilocus sequence typing revealed that isolates with the same emm type were clones having the same allelic profiles. Ninety-eight percent of the pharyngeal isolates had emm types previously found to be highly associated with mga locus gene patterns commonly found in pharyngeal GAS isolates.
Insights
Genetic diversity in group A streptococcus (GAS) was analyzed in pediatric pharyngitis patients. Most isolates showed conserved genetic profiles, with specific M protein gene types linked to common mga locus patterns.
Area of Science:
- Microbiology
- Genetics
- Epidemiology
Background:
- Group A Streptococcus (GAS) is a significant bacterial pathogen causing pharyngitis.
- Understanding the genetic diversity of GAS is crucial for tracking outbreaks and developing effective interventions.
Purpose of the Study:
- To assess the genetic diversity of GAS isolates from pediatric pharyngitis in Rome, Italy.
- To investigate the relationship between M protein gene (emm) types, serum opacity factor/fibronectin binding protein gene (sof) types, and chromosomal macrorestriction profiles.
Main Methods:
- Analysis of 114 GAS isolates from pediatric pharyngitis patients.
- Characterization using M protein gene (emm) sequencing, serum opacity factor/fibronectin binding protein gene (sof) sequencing, chromosomal macrorestriction profiling, and multilocus sequence typing.
Main Results:
- Identified 22 distinct emm sequence types among the isolates.
- Found associations between emm types and specific sof sequence types.
- Demonstrated generally conserved chromosomal macrorestriction profiles within the same emm type.
- Confirmed clonal relationships for isolates with identical emm types but different macrorestriction profiles using multilocus sequence typing.
- Observed that 98% of isolates possessed emm types previously linked to common mga locus gene patterns in pharyngeal GAS.
Conclusions:
- GAS isolates from pediatric pharyngitis in Rome exhibit significant genetic diversity in emm types.
- The study highlights the utility of combining emm typing, sof typing, and macrorestriction profiling for robust genetic characterization of GAS.
- The findings suggest a strong association between pharyngeal GAS emm types and specific mga locus gene patterns, indicating conserved virulence factor gene expression in this population.