RESUMO
The aim of the present study was to characterize genotypically 45 Staphylococcus aureus strains isolated from humans, bovine subclinical mastitis and food samples in Argentina by rep-PCR and PCR amplification of virulence genes. Resistances to various antibiotics could be observed for the human S. aureus, less pronounced for the bovine strains, but not for the eight S. aureus isolated from food samples. The strains could be classified genotypically by rep-PCR and by amplification of the genes encoding protein A, coagulase, clumping factor, the collagen adhesin domains A and B, capsular polysaccharide 5 and 8, the accessory gene regulator agr classes I to III, and the S. aureus gene regulator sae. rep-PCR analyses and the different gene patterns revealed that the strains could be divided into seven groups mostly matching with the origin of the isolates. The present study describes genotypic variations of S. aureus strains isolated from different origins in Argentina. The study provides a valuable insight into molecular specificities of this important pathogen.
Assuntos
DNA Bacteriano/genética , Microbiologia de Alimentos , Mastite Bovina/microbiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/classificação , Staphylococcus aureus/isolamento & purificação , Animais , Argentina , Proteínas de Bactérias/genética , Técnicas de Tipagem Bacteriana , Bovinos , Análise por Conglomerados , Farmacorresistência Bacteriana , Genótipo , Humanos , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Reação em Cadeia da Polimerase/métodos , Staphylococcus aureus/genética , Fatores de Virulência/genéticaRESUMO
In the present study, 87 Staphylococcus aureus isolates obtained from milk samples of 87 cows with mastitis in 6 different municipal districts of 2 regions of Sao Paulo State, Brazil, were compared pheno- and genotypically. Pulsed-field gel electrophoresis (PFGE) analysis of the strains was performed, and PCR was carried out to detect genes for a number of staphylococcal cell surface proteins, exoproteins, and 3 classes of agr genes. Nine distinct S. aureus lineages (LA-LI) were identified by PFGE. The lineages LA and LE, which accounted together for 63 strains (72.2%), were prevalent and had been collected from all of the 6 municipal districts, indicating a broad geographic distribution of these lineages; LB, LC, LD, LF, LG, LH, and LI, however, were isolated sporadically and accounted for 24 strains (27.8%). Some characteristics, like penicillin resistance and the presence of cap8 and agr class II genes, were associated with the prevalent lineages (LA and LE), and penicillin susceptibility and the presence of cna and cap5 genes were associated with sporadic lineages. According to the present results, some S. aureus lineages possess a combination of genes that confer the propensity to cause and disseminate infection, and only a limited number of clones are responsible for the cases of bovine mastitis on the various farms.
Assuntos
Técnicas de Tipagem Bacteriana , Mastite Bovina/microbiologia , Leite/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/classificação , Staphylococcus aureus/genética , Animais , Proteínas de Bactérias/genética , Brasil , Bovinos , DNA Bacteriano/análise , Indústria de Laticínios , Eletroforese em Gel de Campo Pulsado , Feminino , Genótipo , Testes de Sensibilidade Microbiana , Fenótipo , Mapeamento por Restrição , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/isolamento & purificaçãoRESUMO
Serotyping of 50 streptococcal strains of serological group B isolated from human clinical specimens in Chile revealed mainly the serotypes Ia, II and III, either alone or in combination with protein antigens c or R. No significant difference in serotype distribution was detected between group B streptococci isolated from cervical swabs from clinically healthy women and those isolated from various pathological processes. Determination of antibiotic susceptibility of the bacteria demonstrated resistance to tetracycline and minocycline in 29 isolates. All 29 tetracycline-resistant cultures hybridised with a gene probe for tet(M). Again, no differences were detected between the group B streptococcal isolates of various origins.