Abstract
Streptococcus sanguinis is a gram-positive, facultative anaerobe and a normal inhabitant of the human oral cavity. It is also one of the most common agents of infective endocarditis, a serious endovascular infection. To identify virulence factors for infective endocarditis, signature-tagged mutagenesis (STM) was applied to the SK36 strain of S. sanguinis, whose genome is being sequenced. STM allows the large-scale creation, in vivo screening, and recovery of a series of mutants with altered virulence. Screening of 800 mutants by STM identified 38 putative avirulent and 5 putative hypervirulent mutants. Subsequent molecular analysis of a subset of these mutants identified genes encoding undecaprenol kinase, homoserine kinase, anaerobic ribonucleotide reductase, adenylosuccinate lyase, and a hypothetical protein. Virulence reductions ranging from 2-to 150-fold were confirmed by competitive index assays. One putatively hypervirulent strain with a transposon insertion in an intergenic region was identified, though increased virulence was not confirmed in competitive index assays. All mutants grew comparably to SK36 in aerobic broth culture except for the homoserine kinase mutant. Growth of this mutant was restored by the addition of threonine to the medium. Mutants containing an insertion or in-frame deletion in the anaerobic ribonucleotide reductase gene failed to grow under strictly anaerobic conditions. The results suggest that housekeeping functions such as cell wall synthesis, amino acid and nucleic acid synthesis, and the ability to survive under anaerobic conditions are important virulence factors in S. sanguinis endocarditis.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 6064-6074 |
| Number of pages | 11 |
| Journal | Infection and Immunity |
| Volume | 73 |
| Issue number | 9 |
| DOIs | |
| State | Published - Sep 1 2005 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Parasitology
- Microbiology
- Immunology
- Infectious Diseases
Cite this
Identification of virulence determinants for endocarditis in Streptococcus sanguinis by signature-tagged mutagenesis. / Paik, Sehmi; Senty, Lauren; Das, Sankar; Noe, Jody C.; Munro, Cindy; Kitten, Todd.
In: Infection and Immunity, Vol. 73, No. 9, 01.09.2005, p. 6064-6074.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Identification of virulence determinants for endocarditis in Streptococcus sanguinis by signature-tagged mutagenesis
AU - Paik, Sehmi
AU - Senty, Lauren
AU - Das, Sankar
AU - Noe, Jody C.
AU - Munro, Cindy
AU - Kitten, Todd
PY - 2005/9/1
Y1 - 2005/9/1
N2 - Streptococcus sanguinis is a gram-positive, facultative anaerobe and a normal inhabitant of the human oral cavity. It is also one of the most common agents of infective endocarditis, a serious endovascular infection. To identify virulence factors for infective endocarditis, signature-tagged mutagenesis (STM) was applied to the SK36 strain of S. sanguinis, whose genome is being sequenced. STM allows the large-scale creation, in vivo screening, and recovery of a series of mutants with altered virulence. Screening of 800 mutants by STM identified 38 putative avirulent and 5 putative hypervirulent mutants. Subsequent molecular analysis of a subset of these mutants identified genes encoding undecaprenol kinase, homoserine kinase, anaerobic ribonucleotide reductase, adenylosuccinate lyase, and a hypothetical protein. Virulence reductions ranging from 2-to 150-fold were confirmed by competitive index assays. One putatively hypervirulent strain with a transposon insertion in an intergenic region was identified, though increased virulence was not confirmed in competitive index assays. All mutants grew comparably to SK36 in aerobic broth culture except for the homoserine kinase mutant. Growth of this mutant was restored by the addition of threonine to the medium. Mutants containing an insertion or in-frame deletion in the anaerobic ribonucleotide reductase gene failed to grow under strictly anaerobic conditions. The results suggest that housekeeping functions such as cell wall synthesis, amino acid and nucleic acid synthesis, and the ability to survive under anaerobic conditions are important virulence factors in S. sanguinis endocarditis.
AB - Streptococcus sanguinis is a gram-positive, facultative anaerobe and a normal inhabitant of the human oral cavity. It is also one of the most common agents of infective endocarditis, a serious endovascular infection. To identify virulence factors for infective endocarditis, signature-tagged mutagenesis (STM) was applied to the SK36 strain of S. sanguinis, whose genome is being sequenced. STM allows the large-scale creation, in vivo screening, and recovery of a series of mutants with altered virulence. Screening of 800 mutants by STM identified 38 putative avirulent and 5 putative hypervirulent mutants. Subsequent molecular analysis of a subset of these mutants identified genes encoding undecaprenol kinase, homoserine kinase, anaerobic ribonucleotide reductase, adenylosuccinate lyase, and a hypothetical protein. Virulence reductions ranging from 2-to 150-fold were confirmed by competitive index assays. One putatively hypervirulent strain with a transposon insertion in an intergenic region was identified, though increased virulence was not confirmed in competitive index assays. All mutants grew comparably to SK36 in aerobic broth culture except for the homoserine kinase mutant. Growth of this mutant was restored by the addition of threonine to the medium. Mutants containing an insertion or in-frame deletion in the anaerobic ribonucleotide reductase gene failed to grow under strictly anaerobic conditions. The results suggest that housekeeping functions such as cell wall synthesis, amino acid and nucleic acid synthesis, and the ability to survive under anaerobic conditions are important virulence factors in S. sanguinis endocarditis.
UR - http://www.scopus.com/inward/record.url?scp=23944431509&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=23944431509&partnerID=8YFLogxK
U2 - 10.1128/IAI.73.9.6064-6074.2005
DO - 10.1128/IAI.73.9.6064-6074.2005
M3 - Article
C2 - 16113327
AN - SCOPUS:23944431509
VL - 73
SP - 6064
EP - 6074
JO - Infection and Immunity
JF - Infection and Immunity
SN - 0019-9567
IS - 9
ER -