Caracteriza????o de grupos agr e sua rela????o com perfil enterotoxig??nico e antimicrobiano em Staphylococcus aureus isolados de diferentes origens.

O accessory gene regulator (agr) ?? um regulador global de fatores de virul??ncia em S. aureus, como as enterotoxinas estafiloc??cicas (EE), respons??veis pela intoxica????o alimentar estafiloc??cica. S??o conhecidos quatro distintos grupos agr devido ao polimorfismo na seq????ncia dos amino??cidos de agrC e agrD. Na literatura descreve-se rela????o entre fatores de virul??ncia, patogenias, hospedeiro preferencial e perfil de resist??ncia a antibi??ticos com grupos agr. Neste contexto, objetivou-se caracterizar grupos agr atrav??s de biplex PCR, e relacion??-los com os perfis enterotoxig??nico e antimicrobiano de cepas de S. aureus isoladas em alimentos e leite de vacas mast??ticas. Para caracteriza????o dos grupos agr foram utilizadas 115 cepas, sendo 30 isoladas em leite de vacas mast??ticas e 85 em diversas fontes de alimentos. Para a rela????o entre grupos agr e produ????o de enterotoxina foram utilizadas 14/85 cepas previamente caracterizadas quanto ?? presen??a de alguma enterotoxina (eea, eeb, eec, eed e cluster egc), j?? para determinar o perfil de resist??ncia a antibi??ticos utilizaram-se 71/115 cepas. Observou-se uma preval??ncia do grupo agr II, com 19,1% (22/115 cepas), seguido do agr I, com 8,6% (10/115 cepas), agr III 7,8% (9/115 cepas), e agr IV, 6,0% (7/115 cepas). Entre as cepas isoladas em leite de vacas com mastite houve predom??nio do grupo agr I, com 20% (6/30 cepas); j?? nas cepas isoladas de diversas fontes de alimentos observou-se preval??ncia do grupo agr II, com 32,7% (18/85 cepas), especialmente entre as provenientes de carne de frango. Entre as 14/85 cepas que carreavam genes de enterotoxinas, a maioria que albergava o cluster egc (70%), pertencia ao grupo agr II, enquanto nenhuma rela????o foi observada com aquelas que possu??am os genes para as EE cl??ssicas (eea, eeb, eec, eed). Com rela????o ao perfil de resist??ncia antimicrobiana, 100% das cepas isoladas de leite de vacas com mastite e das diversas fontes de alimentos apresentaram resist??ncia ?? penicilina, ampicilina, cefoxitina e vancomicina. Observou-se rela????o entre cepas isoladas de alimentos, que eram resistentes ?? vancomicina e grupo agr II, entretanto, nenhuma rela????o foi observada entre perfil antimicrobiano e grupos agr entre as cepas isoladas em leite de vacas com mastite. Atrav??s destes resultados demonstra-se a preval??ncia do grupo agr II entre as cepas isoladas de alimentos e do grupo agr I em cepas isoladas de leite de vacas mast??ticas. Al??m disso, nas cepas que carreiam o cluster egc houve predomin??ncia do grupo agr II, podendo indicar um grupo clonal entre essas. Outro resultado relevante obtido neste estudo foi ?? elevada taxa de cepas de S. aureus multiresistentes isoladas em alimentos, o que ressalta a import??ncia da dissemina????o de cepas multiresistentes entre os alimentos.he accessory gene regulator (agr) is a S. aureus global regulator of virulence factors, as the staphylococcal enterotoxins (SE), responsible for the staphylococcal food poisoning. There are four different agr groups due to the polymorphism in the amino acids sequence of the agrC and agrD. In the literature is described a relationship among agr groups and virulence factors, diseases, preferential host and antibiotic resistance. In this context, it was aimed to characterize the agr groups through biplex PCR, and relationship among agr groups, enterotoxigenic and antimicrobian profiles of S. aureus isolated from foods and bovine mastitis milk. A total of 115 strains were used to characterize the agr groups , being 30 isolated from f bovine mastitis milk and 85 isolated from several sources of foods. To assess the relationship between agr groups and enterotoxin production were used 14/85 strains previously characterized for the presence of some enterotoxins (sea, seb, sec, sed e cluster egc). To determine the profile of antibiotics resistance were used 71/115 strains. We observed a prevalence of agr group II with19.1% (22/115 strains), followed by the agr I with 8.6% (10/115 strains), agr III with 7.8% (9 / 115 strains), and agr IV with6.0% (7 / 115 strains). Among the strains isolated from bovine mastitis milk agr group I was prevailed with 20% (6/30 strains), whereas in the strains isolated from several food sources was observed prevalence of agr group II with 32.7% (18/85 strains), especially among those from chicken meat. Among the 14 strains (14/85) that contained enterotoxin genes, the majority of them contained the cluster egc (70%) belonged to agr II, whereas no relationship was found with those who had the genes for the classical SE (sea, seb, sec, sed). Considering the antibiotic resistance 100% of bovine mastitis milk strains and from various sources of food were resistant to penicillin, ampicillin, cefoxitin, and vancomycin. Relationship was observed between food strains, which were resistant to vancomycin and agr II, however, no relationship was found between antibiotic profile and agr groups among the strains isolated from bovine mastitis milk. These results demonstrated the prevalence of agr II among food strains and agr I among bovine mastitis milk strains. Moreover, the strains that carried the cluster egc were predominant agr II, which could indicate the occurrence of a clonal group among those. Another important result obtained in this study was the high rate of S. aureus multiresistant strains isolated from food, which emphasizes the importance of dissemination of these strains among foods