Identification of virulence factors in 16S-23S rRNA intergenic spacer genotyped Staphylococcus aureus isolated from water buffaloes and small ruminants

Abstract

Staphylococcus aureus is an important human and animal pathogen, and is regarded as an important cause of intramammary infection (IMI) in ruminants. Staphylococcus aureus genetic variability and virulence factors have been well studied in veterinary medicine, especially in cows as support for control and management of IMI. The aim of the present study was to genotype 71 Staph. aureus isolates from the bulk tank and foremilk of water buffaloes (n=40) and from udder tissue (n=7) and foremilk (n=24) from small ruminants. The method used was previously applied to bovine Staph. aureus and is based on the amplification of the 16S-23S rRNA intergenic spacer region. The technique applied was able to identify different Staph. aureus genotypes isolated from dairy species other than the bovine species, and cluster the genotypes according to species and herds. Virulence gene distribution was consistent with genotype differentiation. The isolates were also characterized through determination of the presence of 19 virulence-associated genes by specific PCR. Enterotoxins A, C, D, G, I, J, and L were associated with Staph. aureus isolates from buffaloes, whereas enterotoxins C and L were linked to small ruminants. Genes coding for methicillin resistance, Panton-Valentine leukocidin, exfoliative toxins A and B, and enterotoxins B, E, and H were undetected. These findings indicate that RNA template-specific PCR is a valid technique for typing Staph. aureus from buffaloes and small ruminants and is a useful tool for understanding udder infection epidemiology.

Staphylococcus aureus Isolates from Bovine Mastitis in Eight Countries: Genotypes, Detection of Genes Encoding Different Toxins and Other Virulence Genes

“…And more, according to previous studies [ 11 , 13 , 15 ], except for Brazil, Germany and USA, the remaining countries showed isolates encoding at least 2 virulence factors out of staphylococcal complement inhibitor ( scn ), chemotaxis inhibitory protein of S. aureus ( chp ) and staphylokinase ( sak ). These virulence factors show activity prevalently against the human innate immune system but their presence among isolates recovered in herds with high prevalence of S. aureus mastitis suggests their involvement also in bovine mammary gland immune response [ 16 ], and should be further studied, especially in Colombia and Tunisia where this gene cluster is quite common [ 17 ].…”

“…As previously described [ 15 ], S. aureus isolates harbouring genes coding for clumping factor ( clfA ), a cell wall-associated protein ( fmtB ), and collagen-binding protein ( cna ) have a greater capability to adhere to extracellular matrix proteins, essential for colonization and the establishment of infections. Our results indicated that, except for the American isolates with a lower presence of fmtB and clfA genes, in the other seven countries these genes were widely present in the circulating isolates particularly in Brazilian and Tunisian ones.…”

Enterotoxin genes, enterotoxin production, and methicillin resistance in Staphylococcus aureus isolated from milk and dairy products in Central Italy

“…In Italy, MRSA have been sporadically identified in bovine milk (Antoci, Pinzone, Nunnari, Stefani, & Cacopardo, 2013;Normanno et al, 2007;Pilla et al, 2012), while they have never been detected in surveys conducted on ovine, caprine or bubaline milk (Cremonesi et al, 2013;Morandi, Brasca, Andrighetto, Lombardi, & Lodi, 2010;Perillo et al, 2012;Spanu et al, 2013;Virdis et al, 2010). At a global level, only a few data are available on the presence of MRSA in dairy products.…”

<em>Staphylococcus aureus </em>Isolates From Bovine Mastitis in Eight Countries: Genotypes, Detection of Genes Encoding Different Toxins and Other Virulence Genes

“…And more, as previously described [15], S. aureus isolates harbouring genes coding for clumping factor (clfA), a cell wall-associated protein (fmtB), and collagen-binding protein (cna) have a greater capability to adhere to extracellular matrix proteins, essential for colonization and the establishment of infections. Our results indicated that, except for the American isolates with a lower presence of fmtB and clfA genes, in the other seven countries these genes were widely present in the circulating isolates particularly in Brazilian and Tunisian ones.…”