Streptolysin S and necrotising infections produced by group G streptococcus

Humar, Deepali; Datta, Vivekananda; Bast, Darrin J.; Beall, Bernard; Azavedo, Joyce C. S. de; Nizet, Victor

doi:10.1016/s0140-6736(02)07371-3

Cited by 122 publications

(129 citation statements)

References 34 publications

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“…The other genes in the operon contribute to the maturation (sagB, sagC, and sagD) and secretion (sagG, sagH, and sagI) of SLS (22,23). The genetic structure of the sag operon is highly conserved in the pyogenic group species (25,26). Recently, the presence of sag operon homologues has been reported in other Gram-positive human pathogens: for example, Clostridium spp.…”

Section: Discussionmentioning

confidence: 99%

Novel Twin Streptolysin S-Like Peptides Encoded in the sag Operon Homologue of Beta-Hemolytic Streptococcus anginosus

Tabata

Nakano

Ohkura

et al. 2013

Journal of Bacteriology

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dStreptococcus anginosus is a member of the anginosus group streptococci, which form part of the normal human oral flora. In contrast to the pyogenic group streptococci, our knowledge of the virulence factors of the anginosus group streptococci, including S. anginosus, is not sufficient to allow a clear understanding of the basis of their pathogenicity. Generally, hemolysins are thought to be important virulence factors in streptococcal infections. In the present study, a sag operon homologue was shown to be responsible for beta-hemolysis in S. anginosus strains by random gene knockout. Interestingly, contrary to pyogenic group streptococci, beta-hemolytic S. anginosus was shown to have two tandem sagA homologues, encoding streptolysin S (SLS)-like peptides, in the sag operon homologue. Gene deletion and complementation experiments revealed that both genes were functional, and these SLS-like peptides were essential for beta-hemolysis in beta-hemolytic S. anginosus. Furthermore, the amino acid sequence of these SLS-like peptides differed from that of the typical SLS of S. pyogenes, especially in their propeptide domain, and an amino acid residue indicated to be important for the cytolytic activity of SLS in S. pyogenes was deleted in both S. anginosus homologues. These data suggest that SLS-like peptides encoded by two sagA homologues in beta-hemolytic S. anginosus may be potential virulence factors with a different structure essential for hemolytic activity and/or the maturation process compared to the typical SLS present in pyogenic group streptococci.

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Section: Discussionmentioning

confidence: 99%

Novel Twin Streptolysin S-Like Peptides Encoded in the sag Operon Homologue of Beta-Hemolytic Streptococcus anginosus

Tabata

Nakano

Ohkura

et al. 2013

Journal of Bacteriology

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“…Inasmuch as there are many fibronectin-binding proteins produced by GAS (20 -25), and the role of DNases in streptococcal pathogenesis is unclear (26,27), attenuated virulence in the irr mutant strain is not readily explained by decreased fbp, mf, and mf3 transcript levels. In contrast, sagA is associated with increased tissue necrosis in mouse models of GAS infection (19,28,29). The observation that sagA transcript levels are decreased in the irr mutant strain correlates with reduced abscess size in infected mice (Fig.…”

Section: Microarray Analysis Of Genes Influenced By Ihk-irrmentioning

confidence: 94%

Engagement of the Pathogen Survival Response Used by Group A Streptococcus to Avert Destruction by Innate Host Defense

Voyich

Braughton

Sturdevant

et al. 2004

The Journal of Immunology

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Neutrophils are a critical component of human innate host defense and efficiently kill the vast majority of invading microorganisms. However, bacterial pathogens such as group A Streptococcus (GAS) successfully avert destruction by neutrophils to cause human infections. Relatively little is known about how pathogens detect components of the innate immune system to respond and survive within the host. In this study, we show that inactivation of a two-component gene regulatory system designated Ihk-Irr significantly attenuates streptococcal virulence in mouse models of soft tissue infection and bacteremia. Microarray analysis of wild-type and irr-negative mutant (irr mutant) GAS strains revealed that Ihk-Irr influenced expression of 20% of all transcripts in the pathogen genome. Notably, at least 11 genes involved in cell wall synthesis, turnover, and/or modification were down-regulated in the irr mutant strain. Compared with the wild-type strain, significantly more of the irr mutant strain was killed by human neutrophil components that destroy bacteria by targeting the cell envelope (cell wall and/or membrane). Unexpectedly, expression of ihk and irr was dramatically increased in the wild-type strain exposed to these same neutrophil products under conditions that favored cell envelope damage. We report a GAS mechanism for detection of innate host defense that initiates the pathogen survival response, in which cell wall synthesis is critical. Importantly, our studies identify specific genes in the pathogen survival response as potential targets to control human infections.

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“…equisimilis possesses many virulence factors shared with GAS, such as M protein (Fischetti, 1989;Schnitzler et al, 1995), streptolysin O (Gerlach et al, 1993;Okumura et al, 1994), streptolysin S (Humar et al, 2002) and streptokinase (Walter et al, 1989;Ikebe et al, 2004). It has been suggested that these factors were transmitted from GAS to this species (Kalia et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Molecular emm genotyping and antibiotic susceptibility of Streptococcus dysgalactiae subsp. equisimilis isolated from invasive and non-invasive infections

Sunaoshi

Murayama

Adachi

et al. 2010

Journal of Medical Microbiology

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To analyse the characteristics of infections caused by Streptococcus dysgalactiae subsp. equisimilis, clinical isolates (n5145) were collected at 11 medical institutions between September 2003 and October 2005. These isolates belonged to Lancefield group A (n55), group C (n518) or group G (n5122). Among all isolates, 42 strains were isolated from sterile samples such as blood, synovial fluid and tissue specimens from patients who were mostly over 50 years with invasive infections, and included seven cases of streptococcal toxic shock syndrome and necrotizing fasciitis. In contrast, the remaining 103 were isolated mainly from patients of all age groups with non-invasive infections such as pharyngotonsillitis. These isolates were classified into 25 types based on emm genotyping. A significant difference in emm types was observed between isolates from invasive and non-invasive infections (P,0.001): stG485, stG6792 and stG2078 predominated among isolates from invasive infections. A phylogenetic tree of complete open reading frames of emm genes in this organism showed high homology with those of Streptococcus pyogenes, but not with those of other streptococci. The presence of five different clones was estimated based on DNA profiles of isolates from invasive infections obtained by PFGE. Genes for resistance to macrolides [erm(A), three isolates; erm(B), five isolates; mef(A), seven isolates] and levofloxacin (mutations in gyrA and parC, four isolates) were identified in this organism. These results suggest the need for further nationwide surveillance of invasive infections caused by S. dysgalactiae subsp. equisimilis. INTRODUCTIONMost b-haemolytic streptococcal pathogens isolated from humans are identified as Streptococcus pyogenes (group A streptococci; GAS), Streptococcus agalactiae (group B streptococci; GBS), Streptococcus dysgalactiae subsp. equisimilis and species of the anginosus group that belong to Lancefield groups A, B, C, G or F (Facklam, 2002;Ruoff et al., 2003). In contrast to GAS and GBS, which are known to cause serious and systemic invasive infections, streptococci with Lancefield group C or G antigens were long considered to be commensal organisms that only rarely caused invasive infections as opportunistic pathogens.In 1996, S. dysgalactiae subsp. equisimilis was proposed as a new streptococcal taxon (Vandamme et al., 1996). Although rare, S. dysgalactiae subsp. equisimilis strains having group A antigen rather than group C or G antigen have also been reported (Bert & Lambert-Zechovsky, 1997;Brandt et al., 1999;Katsukawa et al., 2002 Notably, S. dysgalactiae subsp. equisimilis possesses many virulence factors shared with GAS, such as M protein (Fischetti, 1989; Schnitzler et al., 1995), streptolysin O (Gerlach et al., 1993Okumura et al., 1994), streptolysin S (Humar et al., 2002 and streptokinase (Walter et al., 1989;Ikebe et al., 2004). It has been suggested that these factors were transmitted from GAS to this species (Kalia et al., 2001).In the present report, we have described S. dysgalactiae ...

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Streptolysin S and necrotising infections produced by group G streptococcus

Cited by 122 publications

References 34 publications

Novel Twin Streptolysin S-Like Peptides Encoded in the sag Operon Homologue of Beta-Hemolytic Streptococcus anginosus

Novel Twin Streptolysin S-Like Peptides Encoded in the sag Operon Homologue of Beta-Hemolytic Streptococcus anginosus

Engagement of the Pathogen Survival Response Used by Group A Streptococcus to Avert Destruction by Innate Host Defense

Molecular emm genotyping and antibiotic susceptibility of Streptococcus dysgalactiae subsp. equisimilis isolated from invasive and non-invasive infections

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