Streptococcus suis Serotype 2 Capsule In Vivo.
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ABSTRACT:
SUBMITTER: Auger JP
PROVIDER: S-EPMC5038428 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Within Streptococcus suis serotype 2, pathogenic, weakly pathogenic, and nonpathogenic strains can be found. We introduced a genomic library of a pathogenic strain into a weakly pathogenic strain. After infection of the library into young piglets pathogenic transformants were selected. One specific transformant containing a 3-kb fragment of the pathogenic strain appeared to be dominantly enriched in diseased pigs. The observed enrichment was not tissue specific. The selected fragment, when introduced into two different weakly pathogenic strains, increased the virulence of these strains considerably. In contrast, introduction of the corresponding fragment of a weakly pathogenic strain had only minor effects on virulence. Nucleotide sequence analysis of the selected fragment of the pathogenic strain revealed the presence of two potential open reading frames, both of which were found to be mutated in the corresponding fragment of the weakly pathogenic strain. These data strongly suggest that the selected fragment contains determinants important for virulence.
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Project description:Streptococcus pneumoniae's polysaccharide capsule is an important virulence factor; vaccine-induced immunity to specific capsular polysaccharide effectively prevents disease. Serotype 1 S. pneumoniae is rarely found in healthy persons, but is highly invasive and a common cause of meningitis outbreaks and invasive disease outside of the United States. Here we show that genes for polysaccharide capsule similar to those expressed by pneumococci were commonly detected by polymerase chain reaction among upper respiratory tract samples from older US adults not carrying pneumococci. Serotype 1-specific genes were predominantly detected. In five oropharyngeal samples tested, serotype 1 gene belonging to S. mitis expressed capsules immunologically indistinct from pneumococcal capsules. Whole genome sequencing revealed three distinct S. mitis clones, each representing a cps1 operon highly similar to the pneumococcal cps1 reference operon. These findings raise important questions about the contribution of commensal streptococci to natural immunity against pneumococci, a leading cause of mortality worldwide.
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Project description:Streptococcus suis serotype 2 (SS2), an important zoonotic agent, is notorious for causing contagious porcine diseases and human infection. The two outbreaks in China (in 1998 and in 2005) have caused serious economic losses in the pig industry and posed public health for its new toxin shock symptoms (TSS). However, the molecular mechanism of SS2 pathogenicity is still poorly understood. In order to get insights into pathogenecity of SS2, eighteen SS2 strains of different virulence and sources have been subjected to whole genome comparison by NimbleGen CGS arrays
2009-08-29 | GSE17868 | GEO
Project description:We report 2 adult cases of invasive disease in Japan caused by Streptococcus oralis that expressed the serotype 3 pneumococcal capsule and formed mucoid colonies. Whole-genome sequencing revealed that the identical serotype 3 pneumococcal capsule locus and hyl fragment were recombined into the genomes of 2 distinct S. oralis strains.
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Project description:Streptococcus suis serotype 2 (SS2) is an important zoonotic pathogen with the characteristics of high mortality and morbidity, which brings great challenges to prevent and control epidemic disease in the swine industry. Cathelicidins (CATH) are antimicrobial peptides with antimicrobial and immunomodulatory activities. In this study, bactericidal and anti-inflammatory effects of chicken cathelicidin-1 (CATH-1) were investigated in vitro and in vivo against SS2 infection. The results show that CATH-1 exhibited a better bactericidal effect compared to other species' cathelicidins including chickens (CATH-2, -3, and -B1), mice (CRAMP) and pigs (PMAP-36 and PR-39), which rapidly killed bacteria in 20 min by a time-killing curve assay. Furthermore, CATH-1 destroyed the bacterial morphology and affected bacterial ultrastructure as observed under electron microscopy. Moreover, CATH-1 antibacterial activity in vivo shows that CATH-1 increased survival rate of SS2-infected mice by 60% and significantly reduced the bacterial load in the lungs, liver, spleen, blood, and peritoneal lavage as well as the release of SS2-induced inflammatory cytokines including IL-1α, IL-1β, IL-12, and IL-18. Importantly, CATH-1 did not show severe histopathological changes in mice. Further studies on the mechanism of anti-inflammatory activity show that CATH-1 not only reduced the inflammatory response through direct neutralization, but also by regulating the TLR2/4/NF-κB/ERK pathway. This study provides a scientific basis for the research and development of antimicrobial peptides as new antimicrobial agents.
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Project description:We report here the first complete genome sequence of Streptococcus suis serotype 16, which has been identified to be zoonotic. The sequenced strain TL13 was isolated from a pig in China. The genome is 2,038,146 bp in length, covering 1,950 coding sequences, 53 tRNAs, and 4 rRNA loci.
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Project description:Streptococcus suis is an important zoonotic agent leading to a variety of diseases in swine and can be transmitted to human beings upon close contact. Here, we report the complete genome sequence of S. suis serotype 14 strain JS14 which was isolated from a diseased pig in Jiangsu Province, China.
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Project description:Streptococcus suis is a zoonotic pathogen causing economic loss in the swine industry and is also a threat to human health. To date, the mechanism of pathogenesis is not fully understood. Here, we report the complete genome sequence of S. suis strain ST3 of serotype 3, which provides opportunities to reveal genetic basis of infection of S. suis non-serotype 2 strains.
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Project description:We report here the second complete genome sequence of Streptococcus suis serotype 3 (strain YB51). The genome is 2,043,655 bp in length, which is 14,840 bp longer than the first reported genome of the same serotype, and it covers 2,012 coding sequences, 56 tRNAs, and 4 rRNA loci.
| S-EPMC3814634 | biostudies-literature
Project description:BackgroundStreptococcus suis serotype 2 (S. suis 2, SS2) is a major zoonotic pathogen that causes only sporadic cases of meningitis and sepsis in humans. Most if not all cases of Streptococcal toxic shock syndrome (STSS) that have been well-documented to date were associated with the non-SS2 group A streptococcus (GAS). However, a recent large-scale outbreak of SS2 in Sichuan Province, China, appeared to be caused by more invasive deep-tissue infection with STSS, characterized by acute high fever, vascular collapse, hypotension, shock, and multiple organ failure.Methods and findingsWe investigated this outbreak of SS2 infections in both human and pigs, which took place from July to August, 2005, through clinical observation and laboratory experiments. Clinical and pathological characterization of the human patients revealed the hallmarks of typical STSS, which to date had only been associated with GAS infection. Retrospectively, we found that this outbreak was very similar to an earlier outbreak in Jiangsu Province, China, in 1998. We isolated and analyzed 37 bacterial strains from human specimens and eight from pig specimens of the recent outbreak, as well as three human isolates and two pig isolates from the 1998 outbreak we had kept in our laboratory. The bacterial isolates were examined using light microscopy observation, pig infection experiments, multiplex-PCR assay, as well as restriction fragment length polymorphisms (RFLP) and multiple sequence alignment analyses. Multiple lines of evidence confirmed that highly virulent strains of SS2 were the causative agents of both outbreaks.ConclusionsWe report, to our knowledge for the first time, two outbreaks of STSS caused by SS2, a non-GAS streptococcus. The 2005 outbreak was associated with 38 deaths out of 204 documented human cases; the 1998 outbreak with 14 deaths out of 25 reported human cases. Most of the fatal cases were characterized by STSS; some of them by meningitis or severe septicemia. The molecular mechanisms underlying these human STSS outbreaks in human beings remain unclear and an objective for further study.
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