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

Nature Publishing Group

Año: 2018 vol. 8

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 intramammaryinfection. Based on the wide range of antimicrobial, mucoadhesive and immunostimulant propertiesdemonstrated by chitosan, we have evaluated therapy efciency of chitosan incorporation to cloxacillinantibiotic as well as its efect against diferent bacterial lifestyles of seven CNS isolates from chronicintramammary infections. The therapeutic efects of combinations were evaluated on planktoniccultures, bacterial bioflms and intracellular growth in mammary epithelial cells. We found that bioflmsand intracellular growth forms ofered a strong protection against antibiotic therapy. On the otherhand, we found that chitosan addition to cloxacillin efciently reduced the antibiotic concentrationnecessary for bacterial killing in diferent lifestyle. Remarkably, the combined treatment was not onlyable to inhibit bacterial bioflm establishment and increase preformed bioflm eradication, but it alsoreduced intracellular bacterial viability while it increased IL-6 secretion by infected epithelial cells. Thesefndings provide a new approach to prophylactic drying therapy that could help to improve conventionalantimicrobial treatment against diferent forms of bacterial growth in an efcient, safer and greenermanner reducing multiresistant bacteria generation and spread.