title: Role of emm and mrp genes in the virulence of group A streptococcal isolate 64/14 in a mouse model of skin infection.
abstract: The virulence of group A streptococcal isolate 64/14 and paired isogenic mutants in which either the emm or mrp gene had been insertionally inactivated was compared in mice. Loss of expression of the emm gene product resulted in a significant loss of virulence when the isolate was injected into the skin but had no significant difference when injected intraperitoneally. By contrast, inactivation of the mrp gene caused the organism to be more virulent in the skin, while having no significant effect intraperitoneally. An isogenic mutant, in which the mga gene was inactivated and neither the emm gene nor the mrp gene was expressed, demonstrated no significant difference in virulence from the wild type organism. Organisms recovered from the spleen of mice lethally infected with the mga mutant expressed all Mga-regulated IgG-binding gene products despite the presence of the spectinomycin-resistance cassette, which was used to inactivate the mga gene, in its original position.
authors.affiliation: Department of Microbiology and Immunology, Medical College of Ohio, Toledo 43699-0008, USA. Boyle@opus.mco.edu
authors.forename: M D
authors.initials: MD
authors.lastname: Boyle
authors.forename: R
authors.initials: R
authors.lastname: Raeder
authors.forename: A
authors.initials: A
authors.lastname: Flosdorff
authors.forename: A
authors.initials: A
authors.lastname: Podbielski
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D015153:Blotting, Western; D002352:Carrier Proteins; D004269:DNA, Bacterial / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics; D015870:Gene Expression; D007074:Immunoglobulin G / Q000378:metabolism; D051379:Mice; D016254:Mutagenesis, Insertional; D016133:Polymerase Chain Reaction; D017192:Skin Diseases, Bacterial / Q000235:genetics*; D000198:Spectinomycin / Q000494:pharmacology; D013154:Spleen / Q000382:microbiology; D013290:Streptococcal Infections / Q000235:genetics*; D013297:Streptococcus pyogenes / Q000235:genetics* / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D007074:Immunoglobulin G; C014689:streptococcal M protein; C068267:mry protein, Streptococcus pyogenes; D000198:Spectinomycin