PMID:3679545

Citation	Patel, AH, Nowlan, P, Weavers, ED and Foster, T (1987) Virulence of protein A-deficient and alpha-toxin-deficient mutants of Staphylococcus aureus isolated by allele replacement. Infect. Immun. 55:3103-10
Abstract	The gene coding for protein A (spa) of Staphylococcus aureus 8325-4 has been inactivated by substituting part of the spa coding sequence for a DNA fragment specifying resistance to ethidium bromide. The in vitro-constructed spa::EtBrr substitution mutation was introduced into the S. aureus chromosome by recombinational allele replacement. Southern blot hybridization showed that the in vitro-constructed mutation was present in the chromosomal spa locus. We have previously reported the inactivation of the alpha-toxin gene (hly) by allele replacement with an in vitro-constructed hly::Emr (erythromycin resistance) mutation (M. O'Reilly, J.C.S. de Azavedo, S. Kennedy, and T.J. Foster, Microb. Pathogen. 1:125-138, 1986). A double Spa- Hly- mutant was constructed by transduction. The virulence of Spa- and Hly- mutants was tested by experimental infection of mice. When subcutaneous injections were given, Hly- mutants formed a flat, darkened lesion, whereas Hly+ strains caused a raised, cream lesion. Alpha-toxin was shown to be a major factor in forming subcutaneous lesions and in causing the death of mice injected intraperitoneally. Spa- mutants were slightly less virulent than their Spa+ counterparts, which suggests that protein A is also a virulence factor of S. aureus.
Links	PubMed PMC260034
Keywords	Animals; Bacterial Toxins/deficiency; Chromosome Mapping; Cloning, Molecular; DNA Mutational Analysis; DNA, Bacterial/genetics; Drug Resistance, Microbial; Ethidium/pharmacology; Hemolysin Proteins; Mice; Skin Diseases/microbiology; Skin Diseases/pathology; Staphylococcal Infections/microbiology; Staphylococcal Infections/pathology; Staphylococcal Protein A/deficiency; Staphylococcal Protein A/genetics; Staphylococcus aureus/genetics; Staphylococcus aureus/pathogenicity
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
STAA8:SPA	involved_in	GO:0009405: pathogenesis	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
STAA8:SPA		GO:0009405: pathogenesis	ECO:0000315:		P		Table 5: shows the survival rates of rats when injected with various concentrations of spa- and spa+ genotypes.	complete CACAO 8853
STAA8:HLA	involved_in	GO:0009405: pathogenesis	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
STAA8:HLA		GO:0009405: pathogenesis	ECO:0000315:		P		Table 4: Shows the effect of Hly- and Hly+ mutant genotypes on the size of skin lesions in rats. This was tested with varying doses of inoculum.	complete CACAO 8854

References

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