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

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

Scientific Reports

Macmillan Publishers Limited

Año: 2018

2045-2322

ovine mastitis affects the health of dairy cows and the profitability of herds worldwide. Coagulasenegativestaphylococci (CNS) are the most frequently isolated pathogens in bovine intramammaryinfection. Based on the wide range of antimicrobial, mucoadhesive and immunostimulant propertiesdemonstrated by chitosan, we have evaluated therapy efficiency of chitosan incorporation to cloxacillinantibiotic as well as its effect against different bacterial lifestyles of seven CNS isolates from chronicintramammary infections. The therapeutic effects of combinations were evaluated on planktoniccultures, bacterial biofilms and intracellular growth in mammary epithelial cells. We found that biofilmsand intracellular growth forms offered a strong protection against antibiotic therapy. On the otherhand, we found that chitosan addition to cloxacillin efficiently reduced the antibiotic concentrationnecessary for bacterial killing in different lifestyle. Remarkably, the combined treatment was not onlya