Bibiana Martins Barasuol
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Juliana Felipetto Cargnelutti
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Luis Antônio Sangioni
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Daniela Isabel Brayer Pereira
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Ana Paula Muterle Varela
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Abstract
Bovine mastitis is an important disease of dairy cows, and Staphylococcus aureus is the etiologic agent most prevalent among the microorganisms. Mastitis caused by S. aureus present low cure rate with antimicrobials treatment and low vaccines efficacy. Bacteriophages or phages have been considered as an alternative for treating this disease. This study, we isolated and characterized two new S. aureus phages, namely B_UFSM4 and B_UFSM5, from bovine milk of cows with mastitis. The adsorptions rates were 10–20 min for B_UFSM4 and 20–30 min for B_UFSM5. Phages activities were relatively stable at pH 3–11; however, at temperatures of 50 °C-60ºC-70ºC/60 min, the phages were completely inactivated. These viruses presented infectivity in various bacteria isolated from bovine mastitis, where the lytic activity of phages B_UFSM4 and B_UFSM5 were 34.2%(13/38) and 42.1%(16/38), respectively, including isolates from S. aureus, Pseudomonas aeruginosa, Staphylococcus sciuri, and Rothia terrae. The complete genomes of B_UFSM4 and B_UFSM5 have 41.396 bp and 41.829 bp, with GC-content 33.97% and 33.98%, respectively. Both phages comprise 61 putative ORFs. The viruses have double stranded DNA and linear architecture. Phylogenic similarity was observed by proteome with Staphylococcus prophage phiPV83 (45,536 nt), Staphylococcus phage CN125 (44,492 nt) and Staphylococcus phage JS01 (43,458 nt). Based on the morphology, the phages belong to Siphoviridae family, presenting icosahedral head with a long tail, Caudovirales order and Biseptimavirus genus. Thus, two S. aureus phages (B_UFSM4 and B_UFSM5) were isolated and characterized, and these phages can be used as therapeutic or prophylactic candidates against S. aureus infections in cattle mastitis.
Isolation and characterization of sulfhydryl oxidase from bovine milk.
