Streptococcus species are associated with many human diseases. The genus Streptococcus comprises important pathogens, many of which are part of the human or animal microbiota. The Streptococcus genus has around 49 species and eight subspecies. Of these, 35 have been identified as sources of invasive infections in humans. Neonatal sepsis, meningitis, arthritis, and pneumonia are some examples of these diseases. Group A Streptococcus (GAS) is a gram-positive cocci bacteria that appears in chains and produces small white to grey colonies with a clear zone of β-hemolysis on blood agar, rare strains are not hemolytic. GAS can be subdivided into more than 100 serotypes by the M-protein antigen that is found on the cell surface and by fimbriae. It deploys a range of virulence determinants to allow colonization, dissemination within the host and transmission, disrupting both innate and adaptive immune responses to infection. The GAS cell is a complicated structure, the cell is covered with a hyaluronic acid capsule that makes the colonies mucoid or water drop appearance in rapidly dividing strains. The cell surface and the hyaluronic capsular layer are microscopic hair-like fimbriae that enable adherence of GAS to epithelial cells and extracellular matrix proteins. GAS causes mild infectious diseases such as skin infections and pharyngitis but is also able to cause severe, life-threatening invasive diseases such as streptococcal toxic shock syndrome or necrotizing fasciitis. Recurrent GAS infections may induce autoimmune diseases including rheumatic fever, rheumatic heart disease and acute post-streptococcal glomerulonephritis. Streptococcus pyogenes contain N-acetyl glucosamine linked to rhamnose polymer that is characterized as group A streptococcus. Streptococcus pyogenes is able to infect humans through adhesion and colonization of the host mucosal surface epithelial cells of the upper respiratory tract. The infection rate is more than 600 million infections annually resulting in more than 500,000 deaths a year.
Author(s) Details:
Minas Mohamed Balla Yousif
Department of Microbiology, Faculty of Science, University of Gezira, Wad Medani, Sudan.
Adil Mergani
Department of Molecular and Immunogenetics, NCI, University of Gezira, Wad Medani, Sudan.
Mohamed Elamin A. M. E. Medani
Pediatric Cardiologist, Faculty of Medicine, University of Gezira, Wad Medani, Sudan.
Adam Dawoud Abakar
Department of Medical Parasitology, Faculty of Medical Laboratory Science, University of Gezira, Wad Medani, Sudan.
Recent Global Research Developments in Streptococcus pyogenes: Pathogenicity and Disease
Strain Diversity and Vaccine Development: A systematic review highlighted the high strain diversity of S. pyogenes and its implications for vaccine development. The study identified 211 emm-types from 55 countries, emphasizing the need for a global vaccine that considers the pathogen’s multidimensional diversity [1].
Vaccine Landscape: Recent efforts in S. pyogenes vaccine development have been re-invigorated, with several candidates demonstrating proof of concept in preclinical models. The Strep A Vaccine Global Consortium (SAVAC) has been established to accelerate vaccine development [2].
Public Health Risk Factors: A review identified key public health risk factors and prevention strategies for S. pyogenes infections, which affect millions globally and result in significant mortality. The study emphasized the importance of global surveillance and control measures [3].
State Transitions Across Disease Spectrum: A scoping review synthesized evidence of state transitions across the S. pyogenes disease spectrum, from superficial to life-threatening invasive infections. This review provided insights into the progression and management of various disease states [4].
Pathogenesis and Vaccine Development: Another review focused on the pathogenesis of S. pyogenes and the current status of vaccine development. It discussed the challenges in developing a safe and effective vaccine, considering the pathogen’s genetic heterogeneity and diverse autoimmune responses [5].
References
- Smeesters, P. R., de Crombrugghe, G., Tsoi, S. K., Leclercq, C., Baker, C., Osowicki, J., … & Steer, A. C. (2024). Global Streptococcus pyogenes strain diversity, disease associations, and implications for vaccine development: a systematic review. The Lancet Microbe.
- Walkinshaw, D. R., Wright, M. E., Mullin, A. E., Excler, J. L., Kim, J. H., & Steer, A. C. (2023). The Streptococcus pyogenes vaccine landscape. npj Vaccines, 8(1), 16.
- Parajulee, P., Lee, JS., Abbas, K. et al. State transitions across the Strep A disease spectrum: scoping review and evidence gaps. BMC Infect Dis 24, 108 (2024). https://doi.org/10.1186/s12879-023-08888-4
- Wang J, Ma C, Li M, Gao X, Wu H, Dong W, Wei L. Streptococcus pyogenes: Pathogenesis and the Current Status of Vaccines. Vaccines. 2023; 11(9):1510. https://doi.org/10.3390/vaccines11091510
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