Virulence Factor Profile of <i>Staphylococcus aureus</i> Isolated from Bovine Milk from Brazil

Abstract

This study investigates the biofilm formation, presence and distribution of virulence genes and the capacity to induce an inflammatory response in strains of Staphylococcus aureus isolated from milk samples in Bahia, Brazil. A total of 132 samples of raw milk were collected from four dairy farms (designated A to D) located in southwestern Bahia, in the municipality of Vitória da Conquista, from October/2009 to September/2010. After processing of the samples, 94 (71.2%) S. aureus isolates were obtained. These strains were subjected to the antibiogram method MIC (Minimum Inhibitory Concentration). As for the pathogenicity, tests were performed in vitro biofilm formation induced by glucose. Moreover, we performed PCR for their virulence genes: sea (enterotoxin A), seb (B), sec (C), pvl (Panton-Valentine Leukocidin), clfA (Clumping Factor A) and spa (protein A) and analysis of cytokine induction in the inflammatory response of J774 macrophages by exocellular lipoteichoic acid. No isolates were resistant to oxacillin and vancomycin. In biofilm production, 5.31% (5/94) isolates did not produce biofilm, 5.31% (5/94) of the samples were poor producers, 15.96% (15/94) strains were moderate producers, 18.09% (17/94) were producers and 55.32% (55/94) of isolates were strong biofilm producers. One (1.06%) isolate expressed the seb gene, one (1.06%) sec, 18 (19.2%) cflA and 44 (46.8%) had spa. There was no expression of sea and pvl between isolates analyzed. The analysis of cytokine induction in the inflammatory response did not show statistical difference in the levels of IL-6, TNF-α and IL-10 induction. However, there was statistical difference in IL-1 induction between isolates from different farms. Thus, it

Biofilm formation of Staphylococcus aureus dairy isolates representing different genotypes

“…Another major concern is that Staph. aureus can form biofilms (Santos et al, 2014). Biofilms are aggregates of microbial cells surrounded by a matrix of exopolymers (Costerton et al, 1999).…”

The prevention and removal of biofilm formation of Staphylococcus aureus strains isolated from raw milk samples by citric acid treatments

“…Staphylococcus aureus is a potential foodborne pathogen considered to be the world's third most important causative of foodborne illnesses (Aydin et al, 2011). One major concern is that it is an important pathogen that forms biofilm in dairy industry (Santos et al, 2014). Biofilm formation is a key mechanism involved in Staphylococcus virulence during device-associated infections (Pozzi et al, 2012), and it should be controlled using chemical or organic disinfectants.…”

The Use of Multiplex PCR to Determine the Prevalence of Enterotoxigenic Staphylococcus aureus Isolated from Raw Milk, Feta Cheese, and Hand Swabs

“…S. aureus can cause mastitis, and therefore it can be a contaminant in raw milk. In previous studies, the prevalence of coagulase positive S. aureus in raw milk varied from 18% (Ekici and others ) to 38% (D'Amico and Donnelly ) to 67% (Andre and others ) to 71% (Santos and others ). The different prevalence rates between the different studies can be attributed to different management practices at the farms, different herd health status, or different milk handling methods.…”