Inter-species genetic movement may blur the epidemiology of streptococcal diseases in endemic regions

• Published in: Microbes and infection 2005-07, Vol.7 (9), p.1128-1138
• Main Authors: Davies, Mark R., Tran, Thanh N., McMillan, David J., Gardiner, Donald L., Currie, Bart J., Sriprakash, Kadaba S.
• Format: Article
• Language: English
• Subjects: Adolescent; Bacteriology; Bacteriophages - genetics; Biological and medical sciences; DNA Transposable Elements - genetics; DNA, Bacterial - genetics; Endemic Diseases; Fundamental and applied biological sciences. Psychology; Gene Transfer, Horizontal; Genes, Bacterial; Genome, Bacterial; Group G streptococcus; Horizontal gene transfer; Humans; Male; Microbiology; Miscellaneous; Mobile genetic elements; Molecular Epidemiology; Nucleic Acid Hybridization; Streptococcal Infections - epidemiology; Streptococcal Infections - microbiology; Streptococcal phages; Streptococcus; Streptococcus - genetics; Streptococcus agalactiae; Streptococcus agalactiae - genetics; Streptococcus dysgalactiae; Streptococcus pyogenes; Streptococcus pyogenes - genetics; Virology
• ISSN: 1286-4579; 1769-714X
• DOI: 10.1016/j.micinf.2005.03.018

Streptococcus dysgalactiae subsp. equisimilis (human group G streptococcus, GGS) is generally regarded as a commensal organism but can cause a spectrum of human diseases very similar to that caused by S. pyogenes (group A streptococcus, GAS). Lateral acquisition of genes between these two phylogenetically closely related species is well documented. However, the extent and mechanisms of lateral acquisitions is not known. We report here genomic subtraction between a pathogenic GGS isolate and a community GGS isolate and analyses of the gene sequences unique to the pathovar. Our results show that cross-species genetic transfers are common between GGS and two closely related human pathogens, GAS and the group B streptococcus. We also demonstrate that mobile genetic elements, such as phages and transposons, play an important role in the ongoing inter-species transfers of genetic traits between extant organisms in the community. Furthermore, lateral gene transfers between GAS and GGS may occur more frequently in geographical regions of high GAS endemicity. These observations may have important implications in understanding the epidemiology of streptococcal diseases in such regions.