Characterization of virulence and antibiotic profile and agr typing of Staphylococcus aureus from milk of subclinical mastitis bovine in State of Rio de Janeiro / Caracterização do perfil de virulência e resistência antimicrobiana e tipagem agr de Staphylococcus aureus oriundos do leite bovino de mastite subclinica no estado do Rio de Janeiro

This study aims to detect the main virulence and antimicrobial resistance genes in Stapylococcus aureus from bovine mastitic milk as well as classifying them according to agr typing. A total of 55 strains from six dairy unities in the state of Rio de Janeiro were selected, of these 27.3% presented fbnA and 78,2% for fbnB genes, respectively. None of the strains tested were positive for cap5 gene, 3.6% were positive for cap8 gene. Additionally, 94.5% of strains had hlA gene and 89.1% had hlB gene while 67.3% of the strains had icaA gene and 87.3% had icaD gene. From these results it was possible to establish 12 different virulence profiles. Prevalence of agrII type was detected in 81.8% of the isolates. Concerning antimicrobial resistance evaluation, the studied strains were susceptible to all antibiotics tested except penicillin, 83.6% being resistant strains. None of the strains had mecA gene, however, 40% of the strains had blaZ gene. Associating virulence and resistance data made it possible to obtain 23 different profiles. This great diversity of strains shows wide array of bacterial strategies and the challenge of mastitis prevention in cattle. Despite antimicrobial susceptibility, these strains presented certain genes that allow its persistence in the herd.(AU)

O presente estudo teve como objetivo detectar os principais genes de virulência e resistência antimicrobiana em Staphylococcus aureus oriundos de leite bovino mastítico e classificá-los de acordo com a tipagem do gene agr. Foram selecionados 55 isolados de seis unidades produtores no estado do Rio de Janeiro. Destas, o gene fbnA foi encontrado em 27,3% das cepas e 78,2% possuíam o gene fbnB. Em nenhuma cepa foi encontrado o gene cap5 e 3,6% possuíam o gene cap8. O gene hlA foi encontrado em 94,5% das cepas e 89,1% possuíam o gene hlB. O gene icaA foi encontrado em 67,3% das cepas e 87,3% possuíam o gene icaD. Com base nesses resultados, foi possível estabelecer 12 diferentes perfis de virulência. Prevalência do agr tipo II foi detectada em 81,8% dos isolados. Considerando-se a avaliação da resistência antimicrobiana, as cepas estudadas foram suscetíveis a todos os antibióticos exceto penicilina, sendo detectado um percentual de 83,6% de cepas resistentes. Nenhuma das cepas apresentou o gene mecA, contudo 40% das cepas apresentaram o gene blaZ. Vinte e três perfis diferentes foram estabelecidos por associação de dados de virulência e resistência. Essa grande diversidade de cepas mostra a ampla gama de estratégias bacterianas e o desafio da prevenção à mastite no gado bovino, considerando-se que, a despeito da suscetibilidade antimicrobiana, essas cepas apresentam genes que permitem sua persistência no rebanho.(AU)

Prevalence and molecular proifle of theStaphylococcus aureus strains harboring tstand/or pvl genes / 中国感染与化疗杂志

Objective To investigate the prevalence, accessory gene regulator (agr) and staphylococcal cassette chromosome mec (SCCmec, only for methicillin resistantS. aureus, MRSA) types of theS. aureus strains carrying toxic shock syndrome toxin-1 (tst) and/or panton-valentine leukocidin (pvl) genes.Methods Nine hundred and sixteen isolates ofS. aureus were collected from seven hospitals in Shanghai and Zhejiang Province and subjected to detection oftst,pvl,mecA andmecC genes by polymerase chain reaction (PCR). Theagr and SCCmec (only for MRSA) types were determined in thetst orpvl gene positive isolates.Results Of the 916 isolates, 208 carriedtst gene (22.7%), 35 harboredpvl gene (3.8%), and 665 weremecA positive (MRSA). No isolate was mecC positive. Out of the 665 MRSA isolates, 198 hosted thetst gene (29.8%). The most commonagr and SCCmec types were agr 2 (97.0%) and SCCmec II (94.4%), respectively. For thepvl gene, only 14 isolates were positive (2.1%). Theagr 1 (85.7%), SCCmecIII (42.9%) and SCCmec IVa (28.6%) were the most commonagr type and SCCmec type. In the 251 methicillin-sensitiveS. aureus (MSSA) isolates, 10 carriedtst gene (4.0%) and 21 carriedpvl gene (8.4%). The prevalence oftst gene in MRSA was higher than that in MSSA, while the prevalence ofpvlgene was just the opposite. However, the prevalence ofpvlgene in MRSA isolates from Zhejiang Province was higher than that in the MRSA isolates from Shanghai (P severeS. aureus infections.