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A functional genomic analysis of type 3 Streptococcus pneumoniae virulence
Author(s) -
Lau Gee W.,
Haataja Sauli,
Lonetto Michael,
Kensit Sarah E.,
Marra Andrea,
Bryant Alexander P.,
McDevitt Damien,
Morrison Donald A.,
Holden David W.
Publication year - 2001
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2001.02335.x
Subject(s) - biology , streptococcus pneumoniae , virulence , microbiology and biotechnology , genetics , gene , antibiotics
Streptococcus pneumoniae remains a serious cause of morbidity and mortality in humans, but relatively little is known about the molecular basis of its pathogenesis. We used signature‐tagged mutagenesis together with an analysis of S. pneumoniae genome sequence to identify and characterize genes required for pathogenesis. A library of signature‐tagged mutants was created by insertion–duplication mutagenesis, and 1786 strains were analysed for their inability to survive and replicate in murine models of pneumonia and bacteraemia. One hundred and eighty‐six mutant strains were identified as attenuated, and 56 were selected for further genetic characterization based on their ability to excise the integrated plasmid spontaneously. The genomic DNA inserts of the plasmids were cloned in Escherichia coli and sequenced. These sequences were subjected to database searches, including the S. pneumoniae genome sequence, which allowed us to examine the chromosomal regions flanking these genes. Most of the insertions were in probable operons, but no pathogenicity islands were found. Forty‐two novel virulence loci were identified. Five strains mutated in genes involved in gene regulation, cation transport or stress tolerance were shown to be highly attenuated when tested individually in a murine respiratory tract infection model. Additional experiments also suggest that induction of competence for genetic transformation has a role in virulence.