Chitosan and cloxacillin combination improve antibiotic efficacy against different lifestyle of coagulase-negative Staphylococcus isolates from chronic bovine mastitis

BRESER, MARÍA L.; FELIPE, VERÓNICA; BOHL, LUCIANA P.; ORELLANO, MARÍA S.; ISAAC, PAULA; CONESA, AGUSTÍN; RIVERO, VIRGINIA E.; CORREA, SILVIA G.; BIANCO, ISMAEL D.; PORPORATTO, CARINA

Scientific Reports

Springer Nature

Lugar: New York; Año: 2018 vol. 8

ovine mastitis affects the health of dairy cows and the profitability of herds worldwide. Coagulase-negative staphylococci (CNS) are the most frequently isolated pathogens in bovine intramammary infection. Based on the wide range of antimicrobial, mucoadhesive and immunostimulant properties demonstrated by chitosan, we have evaluated therapy efficiency of chitosan incorporation to cloxacillin antibiotic as well as its effect against different bacterial lifestyles of seven CNS isolates from chronic intramammary infections. The therapeutic effects of combinations were evaluated on planktonic cultures, bacterial biofilms and intracellular growth in mammary epithelial cells. We found that biofilms and intracellular growth forms offered a strong protection against antibiotic therapy. On the other hand, we found that chitosan addition to cloxacillin efficiently reduced the antibiotic concentration necessary for bacterial killing in different lifestyle. Remarkably, the combined treatment was