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Infection and immunity1999; 67(6); 2776-2782; doi: 10.1128/IAI.67.6.2776-2782.1999

Molecular characterization of equine isolates of Streptococcus pneumoniae: natural disruption of genes encoding the virulence factors pneumolysin and autolysin.

Abstract: Although often considered a strict human pathogen, Streptococcus pneumoniae has been reported to infect and cause pneumonia in horses, although the pathology appears restricted compared to that of human infections. Here we report on the molecular characterization of a group of S. pneumoniae isolates obtained from horses in England and Ireland. Despite being obtained from geographically distinct locations, the isolates were found to represent a tight clonal group, virtually identical to each other but genetically distinguishable from more than 120 divergent isolates of human S. pneumoniae. A comprehensive analysis of known pneumococcal virulence determinants was undertaken in an attempt to understand the pathogenicity of equine pneumococci. Surprisingly, equine isolates appear to lack activities associated with both the hemolytic cytotoxin pneumolysin, often considered a major virulence factor of pneumococci, and the major autolysin gene lytA, also considered an important virulence factor. In support of phenotypic data, molecular studies demonstrated a deletion of parts of the coding sequences of both lytA and ply genes in equine pneumococci. The implications of these findings for the evolution and pathogenicity of equine S. pneumoniae are discussed.
Publication Date: 1999-05-25 PubMed ID: 10338480PubMed Central: PMC96581DOI: 10.1128/IAI.67.6.2776-2782.1999Google Scholar: Lookup
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  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The study entails the molecular examination of Streptococcus pneumoniae (a bacterial pathogen) isolates in horses from England and Ireland. Despite the different locations, the isolates were genetically similar to each other but varied from those found in human variants of the bacteria. Interestingly, these equine isolates also seemed deficient in pneumolysin and autolysin, activity, two commonly considered virulence factors in Streptococcus pneumoniae.

Findings on Different Strains of S. pneumoniae

  • The paper presents an in-depth analysis of S. pneumoniae strains isolated from horses within England and Ireland. These locations are geographically distinct, but the S. pneumoniae present in these horse populations displayed a tight similarity in a genetic sense.
  • Interestingly, while these horse-based isolates were similar to each other, they were noticeably different from over 120 divergent isolates of S. pneumoniae found in human hosts.

Analysis of Virulence Determinants

  • The researchers undertook a comprehensive exploration of known pneumococcal virulence determinants to help understand the pathogenicity of S. pneumoniae in horses.
  • Surprisingly, the equine isolates seemed to lack activities associated with both pneumolysin and the major autolysin gene lytA.
  • Pneumolysin, a hemolytic cytotoxin, and LytA, a major autolysin gene, are often considered major virulence factors in S. pneumoniae, contributing to its ability to cause disease in its host.

Molecular Studies and Implications

  • The study showed molecular evidence of deleted sections in the coding sequences of both the lytA and ply genes in the equine pneumococci. This supports the phenotypic data observed, where the pathogenic activities related to these genes were absent in the equine isolates.
  • The discoveries made in the study hold significant implications for the understanding of how equine S. pneumoniae evolved and its pathogenicity in horses.
  • The absence of two major virulence factors in the equine isolates of S. pneumoniae changes our understanding of the bacteria’s ability to cause disease, and may have implications for understanding the disease in humans as well.

Cite This Article

APA
Whatmore AM, King SJ, Doherty NC, Sturgeon D, Chanter N, Dowson CG. (1999). Molecular characterization of equine isolates of Streptococcus pneumoniae: natural disruption of genes encoding the virulence factors pneumolysin and autolysin. Infect Immun, 67(6), 2776-2782. https://doi.org/10.1128/IAI.67.6.2776-2782.1999

Publication

ISSN: 0019-9567
NlmUniqueID: 0246127
Country: United States
Language: English
Volume: 67
Issue: 6
Pages: 2776-2782

Researcher Affiliations

Whatmore, A M
  • Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom. a.m.whatwore@warwick.ac.uk
King, S J
    Doherty, N C
      Sturgeon, D
        Chanter, N
          Dowson, C G

            MeSH Terms

            • Animals
            • Artificial Gene Fusion
            • Bacterial Proteins
            • Base Sequence
            • DNA, Bacterial
            • Enzymes / genetics
            • Genes, Bacterial
            • Horse Diseases / microbiology
            • Horses
            • Humans
            • Molecular Sequence Data
            • N-Acetylmuramoyl-L-alanine Amidase / genetics
            • Pneumococcal Infections / microbiology
            • Pneumococcal Infections / veterinary
            • Streptococcus pneumoniae / classification
            • Streptococcus pneumoniae / genetics
            • Streptococcus pneumoniae / isolation & purification
            • Streptococcus pneumoniae / pathogenicity
            • Streptolysins / genetics
            • Virulence

            Grant Funding

            • Wellcome Trust

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