Background: The gradual replacement of the Streptococcus pyogenes M1global genotype by a newly emergent M1UK variant is a global public health threat warranting increased surveillance. M1UK differs from progenitor M1global genotype by 27 single-nucleotide polymorphisms and is characterized by increased speA superantigen expression in vitro.
Methods: An allele-specific real-time polymerase chain reaction assay was developed for the rapid detection of M1UK strains. The assay was used in combination with whole genome sequencing to determine emm (sub)type distribution for 51 invasive (n = 9) and noninvasive (n = 42) S pyogenes clinical isolates.
Results: Emm1 was the most prevalent S pyogenes emm serotype (n = 11) in this set of clinical isolates, with M1UK being the dominant emm1 genotype (4/5 invasive, 3/6 noninvasive isolates). The assay accurately detected M1UK strains. Whole genome sequencing revealed continued presence of Australian M1UK sublineages associated with epidemic scarlet fever-causing S pyogenes in Asia.
Conclusions: Our study establishes a suitable target for detection of the toxigenic M1UK and confirms the maintenance of M1UK strains in Queensland, Australia. This assay can be deployed in laboratories and provides a valuable, cost-effective tool to enhance surveillance of the expanding M1UK clone.
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http://dx.doi.org/10.1093/infdis/jiae437 | DOI Listing |
Cureus
January 2025
Critical Care Medicine, National Center for Child Health and Development, Tokyo, JPN.
Invasive group A streptococcal (iGAS) infections are known to be potentially life-threatening. Few detailed pediatric cases of streptococcal toxic shock syndrome (STSS) caused by iGAS with the M1 strain have been reported. This report describes the case of a child with STSS due to M1 strain, with detailed documentation of the treatment progress.
View Article and Find Full Text PDFJ Infect Public Health
February 2025
Microbiology and Virology Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.
Background: During 2022 and 2023, a large upsurge of cases of Group A Streptococcus (GAS) infection has struck many countries worldwide. This large epidemic event was caused by a diminished level of immunity after COVID-19 social restrictions and was fostered mainly by the emm1 genotype of the bacterium.
Methods: We characterized the genomes of the GAS isolates that caused bloodstream infections in the last ten years in a 900-bed hospital in Northern Italy.
Microbiol Spectr
February 2025
Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Invasive Group A streptococcal (iGAS) infections are rising in Canada and wordwide. The 2022-2023 Ontario iGAS season was among the highest recorded, a trend continuing in 2023-2024. We sequenced 38 invasive (blood) and 117 non-invasive (pharyngeal) clinical isolates from Toronto (January-May 2023) to compare between the two cohorts and against published sequences to determine if any genomic changes accounted for the trend.
View Article and Find Full Text PDFLancet Reg Health West Pac
February 2025
Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia.
Background: Invasive group A (iGAS) cases have increased globally in 2022-2023, raising concerns within the medical and public health communities, including in Australia, while this impact is polyclonal in nature the worldwide spread and dominance of M1 has been particularly concerning.
Methods: To investigate these changes and prepare to implement routine genomic surveillance of iGAS for public health purposes, we performed whole genome sequencing (WGS) on iGAS isolates from Victoria, Australia between 2017 and 2022. Genomic analyses were conducted to determine the epidemiology, genetic diversity, and population dynamics of iGAS.
Microorganisms
January 2025
Medical Faculty, Sofia University "St. Kliment Ohridski", 1407 Sofia, Bulgaria.
Recently a resurgence of has arisen, with concerns around the highly virulent M1 lineage. Our aim was to characterize , the immune responses it causes, and to determine the presence of the M1 lineage in Sofia, Bulgaria. In our study, the infections were confirmed by culture testing or rapid antigen test.
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