Frequency of Staphylococcus aureus virulence genes in milk of cows and goats with mastitis

Abstract

The present study determined the frequency of Staphylococcus aureus virulence genes in 2,253 milk samples of cows (n=1000) and goats (n=1253) raised in three different geographical regions of the state Pernambuco, Brazil. The presence of genes of virulence factors associated to adhesion to host cells (fnbA, fnbB, clfA and clfB), toxinosis (sea, seb, sec, sed, seg, seh, sei, tsst, hla and hlb), and capsular polysaccharide (cap5 and cap8) was evaluated by PCR. A total of 123 and 27 S. aureus strains were isolated from cows' and goats' milk, respectively. The sec and tsst genes were detected exclusively in goats' isolates, while the seh gene was only identified in cows' isolates. The number of toxin genes per strain showed that goats' isolates are likely more toxic than bovines' isolates. The cap5 genotype predominated in both host species, especially in strains collected from cows raised in the Agreste region. The cap8 genotype is likely more virulent due to the number of virulence genes per strain. The results of the present study demonstrate that S. aureus may pose a potential threat to human health in Brazil, and, therefore, these results should support actions related to mastitis control programs.

Molecular characterization and genetic diversity of Staphylococcus aureus isolates of dairy production farms in Rio de Janeiro, Brazil

“…Our results corroborate with Marques et al (2017) that showed a high abundance of genes icaA and icaD in S. aureus isolates, producing biofilm in samples from bovine intramammary infections in Brazil. Acosta et al (2018) reported a high frequency of fnbA (94%), fnbB (81.3%), hlA (88%) and hlB (88.3%) genes in S. aureus from milk samples, and these genes were more abundant in samples from bovine milk than goat milk in a recent study developed in cow and goat herds raised in three different geographical regions of the state of Pernambuco, Brazil, and these results corroborate with our data.…”

Multiple antibiotic resistance and virulence factors of Staphylococcus aureus strains isolated from dairy farms in South Sulawesi, Indonesia

“…The pathogenicity of S. aureus is related to its ability to produce and secrete a variety of virulence factors that play a role in the colonization, invasion, and degradation of host cells, immune evasion, and bacterial spread (Pietrocola et al 2017;Cheung et al 2021). The fnbA and clfA genes are virulence factors implicated in host cell adhesion, while the sea, tst, and hla were reported to be associated with toxins (Acosta et al 2018). The present study revealed that virulence factors fnbA, hla, clfA, and tst genes were detected in S. aureus isolates derived from animal and human samples.…”

“…None of the S. aureus isolates obtained in the present study harbored the sea gene. The existence of fnbA, clfA, hla, sea, and tst in isolates from animal samples has been previously reported by Acosta et al (2018). Another study reported the presence of the tst gene, but not the sea gene in the isolates from animal (raw milk) and human samples (Vitale et al 2019).…”

Antimicrobial properties of heterocyclic compounds against clinical mastitis isolates

“…Sample selection criteria. Milk samples were collected from 1000 cows from 24 bovine herds from the state of Pernambuco, Brazil as described by (Acosta et al 2018). Only milk samples from cows with clinical signs of mastitis and that had not been treated with antibiotics for at least three weeks were used in the present study.…”