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

Abstract

Staphylococcus aureus is recognized worldwide as one of the major agents of dairy cow intra-mammary infections. This microorganism can express a wide spectrum of pathogenic factors used to attach, colonize, invade and infect the host. The present study evaluated 120 isolates from eight different countries that were genotyped by RS-PCR and investigated for 26 different virulence factors to increase the knowledge on the circulating genetic lineages among the cow population with mastitis. New genotypes were observed for South African strains while for all the other countries new variants of existing genotypes were detected. For each country, a specific genotypic pattern was found. Among the virulence factors, fmtB, cna, clfA and leucocidins genes were the most frequent. The sea and sei genes were present in seven out of eight countries; seh showed high frequency in South American countries (Brazil, Colombia, Argentina), while sel was harboured especially in one Mediterranean country (Tunisia). The etb, seb and see genes were not detected in any of the isolates, while only two isolates were MRSA (Germany and Italy) confirming the low diffusion of methicillin resistance microorganism among bovine mastitis isolates. This work demonstrated the wide variety of S. aureus genotypes found in dairy cattle worldwide. This condition suggests that considering the region of interest might help to formulate strategies for reducing the infection spreading.

Differences in virulence between the two more prevalent Staphylococcus aureus clonal complexes in rabbitries (CC121 and CC96) using an experimental model of mammary gland infection

“…The profile of the bacterial virulence genes detected in strains ST121 and ST96 matched those previously described for clonal complexes CC121 and CC96 [29]. Although variation in molecular profiles has already been described depending on the genotype [14,29,48,49], the detected genetic differences could justify variations in virulence between strain ST121 and strain ST96 as the gene expression and regulation of virulence elements in S. aureus isolates are generally controlled by global gene regulators [50]. Therefore, it would be necessary to increase knowledge about the gene expression and regulation of these virulence elements in strains ST121 and ST96 to better understand their role in the pathogenesis of staphylococcal infections.…”

Antimicrobial Effect of Zophobas morio Hemolymph against Bovine Mastitis Pathogens

“…As described above, E. coli and S. aureus are two of the major pathogens inducing BM, and E. coli CVCC1450 is the most commonly used strain in BM studies [ 29 , 30 ]. S. simulans , a non- aureus staphylococci species, is also responsible for subclinical BM [ 31 ].…”

Nanoparticles for treatment of bovine Staphylococcus aureus mastitis

“…Bovine mastitis, generally caused by several different bacteria, is one of the most devastating diseases in dairy herds worldwide (Tiwari et al, 2013;Ruegg, 2017). Among these bacteria, S. aureus is a predominant pathogen causing the highest virulent forms of bovine mastitis and strikes the greatest challenge to dairy production in most countries (Monistero et al, 2018). This bacterium causes significant economic losses, including a severe decline in milk revenue, reproductive complications, and expenses incurred from the culling of infected animals, increased costs of veterinary medication, and replacing tainted milk (Hogeveen, 2005;Hogeveen et al, 2011;Deb et al, 2013;Botaro et al, 2015;Gomes & Henriques, 2016).…”