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

BRESER ML; FELIPE, V; BOHL LP; ORELLANO MS; ISAAC P; CONESA A; RIVERO VE; CORREA SG; BIANCO ID; PORPORATTO C

Scientific Reports

Nature Publishing Group

Lugar: Londres; Año: 2018 vol. 8 p. 1 - 13

Bovine mastitis afects the health of dairy cows and the proftability of herds worldwide. Coagulasenegative 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 efciency of chitosan incorporation to cloxacillin antibiotic as well as its efect against diferent bacterial lifestyles of seven CNS isolates from chronic intramammary infections. The therapeutic efects of combinations were evaluated on planktonic cultures, bacterial bioflms and intracellular growth in mammary epithelial cells. We found that bioflms and intracellular growth forms ofered a strong protection against antibiotic therapy. On the other hand, we found that chitosan addition to cloxacillin efciently reduced the antibiotic concentration necessary for bacterial killing in diferent lifestyle. Remarkably, the combined treatment was not only able to inhibit bacterial bioflm establishment and increase preformed bioflm radication, but it also reduced intracellular bacterial viability while it increased IL-6 secretion by infected epithelial cells. These fndings provide a new approach to prophylactic drying therapy that could help to improve conventional antimicrobial treatment against diferent forms of bacterial growth in an efcient, safer and greener manner reducing multiresistant bacteria generation and spread.