Genetic relationships and virulence factors in Staphylococcus aureus isolated from raw poultry in South Brazil

Abstract

The genetic relationships in Staphylococcus aureus isolated from raw poultry obtained from various Brazilian broiler chicken processors were analyzed using repetitive extragenic palindromic-polymerase chain reaction (rep-PCR). The distribution of accessory gene regulator (agr) groups was determined, and the presence of biofilm-associated genes and phenotypic features, including biofilm formation and proteolytic, lipolytic, and β-hemolytic activities, was assessed. Isolates were grouped into three major clusters based on rep-PCR fingerprints typed with RW3A primer. The agr group I was the most common genotype identified (86.21 %), followed by groups II (10.34 %) and III (3.45 %). All strains were positive for the sasG gene; the next most frequent genes were icaA (93.1 %) and atlA (51.72 %). Twenty-six of the 29 isolates were biofilm producers. In this study, 96.55 %, 72.41 %, and 62.06 % of the isolates displayed lipolytic, β-hemolytic, and proteolytic activity, respectively. In conclusion, the rep-PCR results suggested a clonal relationship among the S. aureus isolated from raw poultry produced by different broiler chicken processors. Our results also showed that most isolates belonged to agr group I. The presence of biofilm-forming S. aureus strains in raw poultry, their ability to harbor biofilm-associated genes, and the spoilage features that they exhibit are indicative of their pathogenic potential, and may represent a serious problem in the food processing industry.