Potential Factors Enabling Human Body Colonization by Animal Streptococcus dysgalactiae subsp. equisimilis Strains

Current Microbiology, Mar 2017

Streptococcus dysgalactiae subsp. equisimilis (SDSE) is a pyogenic, Lancefield C or G streptococcal pathogen. Until recently, it has been considered as an exclusive animal pathogen. Nowadays, it is responsible for both animal infections in wild animals, pets, and livestock and human infections often clinically similar to the ones caused by group A streptococcus (Streptococcus pyogenes). The risk of zoonotic infection is the most significant in people having regular contact with animals, such as veterinarians, cattlemen, and farmers. SDSE is also prevalent on skin of healthy dogs, cats, and horses, which pose a risk also to people having contact with companion animals. The main aim of this study was to evaluate if there are features differentiating animal and human SDSE isolates, especially in virulence factors involved in the first stages of pathogenesis (adhesion and colonization). Equal groups of human and animal SDSE clinical strains were obtained from superficial infections (skin, wounds, abscesses). The presence of five virulence genes (prtF1, prtF2, lmb, cbp, emm type) was evaluated, as well as ability to form bacterial biofilm and produce BLIS (bacteriocin-like inhibitory substances) which are active against human skin microbiota. The study showed that the presence of genes coding for fibronectin-binding protein and M protein, as well as BLIS activity inhibiting the growth of Corynebacterium spp. strains might constitute the virulence factors which are necessary to colonize human organism, whereas they are not crucial in animal infections. Those virulence factors might be horizontally transferred from human streptococci to animal SDSE strains, enabling their ability to colonize human organism.

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Potential Factors Enabling Human Body Colonization by Animal Streptococcus dysgalactiae subsp. equisimilis Strains

Curr Microbiol Potential Factors Enabling Human Body Colonization by Animal Streptococcus dysgalactiae subsp. equisimilis Strains Marcin Ciszewski 0 Eligia M. Szewczyk 0 0 Department of Pharmaceutical Microbiology and Microbiological Diagnostics, Medical University of Łódź , 137 Pomorska St., 90-235 Lodz , Poland 1 Marcin Ciszewski Streptococcus dysgalactiae subsp. equisimilis (SDSE) is a pyogenic, Lancefield C or G streptococcal pathogen. Until recently, it has been considered as an exclusive animal pathogen. Nowadays, it is responsible for both animal infections in wild animals, pets, and livestock and human infections often clinically similar to the ones caused by group A streptococcus (Streptococcus pyogenes). The risk of zoonotic infection is the most significant in people having regular contact with animals, such as veterinarians, cattlemen, and farmers. SDSE is also prevalent on skin of healthy dogs, cats, and horses, which pose a risk also to people having contact with companion animals. The main aim of this study was to evaluate if there are features differentiating animal and human SDSE isolates, especially in virulence factors involved in the first stages of pathogenesis (adhesion and colonization). Equal groups of human and animal SDSE clinical strains were obtained from superficial infections (skin, wounds, abscesses). The presence of five virulence genes (prtF1, prtF2, lmb, cbp, emm type) was evaluated, as well as ability to form bacterial biofilm and produce BLIS (bacteriocin-like inhibitory substances) which are active against human skin microbiota. The study showed that the presence of genes coding for fibronectin-binding protein and M protein, as well as BLIS activity inhibiting the growth of Corynebacterium spp. strains might constitute the virulence factors which are necessary to colonize human organism, whereas they are not crucial in animal infections. Those virulence factors might be horizontally transferred from human streptococci to animal SDSE strains, enabling their ability to colonize human organism. Streptococcus dysgalactiae subsp; equisimilis; Animal-to-human transfer; Virulence factors; Adhesion; Colonization resistance; Biofilm formation Introduction Streptococcus dysgalactiae subsp. equisimilis (SDSE) is a pyogenic pathogen possessing Lancefield C or G antigens. Until recently, it has been considered as an exclusive animal pathogen. Nowadays, it is responsible for both animal infections in wild animals, pets, and livestock [ 1–4 ] and human infections often clinically similar to the ones caused by group A streptococcus (Streptococcus pyogenes) [ 5–7 ]. According to the outline of evolutionary changes involved in crossing an animal-to-human interspecies barrier, presented by Wolfe et  al. in Nature [8], SDSE is probably located on the second stage of this process—it is being isolated from humans, what has already been reported [ 9, 10 ]; however, there is no evidence for human-to-human transfer. Due to the similarity of SDSE and S. pyogenes virulence factors identified so far, as well as clinical pictures of human infections caused by these pathogens, horizontal gene transfer (HGT) between these species has been suggested [11], especially via bacteriophage transduction process [ 12 ]. HGT might also occur between SDSE strains, as an element of adaptation to the new ecological niche, i.e., human organism [ 13 ]. Bacterial pathogenesis consists of complex set of mechanisms, comprising adhesion, colonization, and spreading in the human organism, inactivation of human immunological system elements as well as production of toxins [ 14 ]. The first process, which involves various virulence factors of animal and human SDSE strains, is adhesion which comprises biofilm formation, the presence of M protein, fibronectin, laminin, and collagen binding proteins as well as the production of BLIS (bacteriocin-like inhibitory substances) enabling colonization of human skin microbiota [ 15, 16 ]. In order to determine factors that might be specific markers enabling animal SDSE strains to break interspecies barrier and colonize human organism, the prevalence of virulence factors involved in adhesion and colonization processes both in groups of human and animal clinical SDSE strains has been evaluated and compared. Materials and Methods Bacterial Strains Six human SDSE isolates from superficial infections (from dermatitis, wounds, bedsores, skin abscesses) were obtained from Synevo Medical Laboratory in Łódź, Poland. Six animal SDSE isolates from clinical cases in pets (dogs—from wounds, skin abscesses) were obtained from VETCOMPLEX Veterinary Diagnostic Centre in Łódź, Poland. Identification MALDI-TOF technique (matrix-assisted laser desorption ionization-time of flight) [ 17 ] which compares cell proteins specters with database (bioMérieux VITEK® MS) was used to identify the analyzed clinical strains. All bacterial strains were also identified by means of RISA ( (...truncated)


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Marcin Ciszewski, Eligia M. Szewczyk. Potential Factors Enabling Human Body Colonization by Animal Streptococcus dysgalactiae subsp. equisimilis Strains, Current Microbiology, 2017, pp. 650-654, Volume 74, Issue 5, DOI: 10.1007/s00284-017-1232-z