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

Abstract

Bovine 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 not only able to inhibit bacterial biofilm establishment and increase preformed biofilm eradication, but it also reduced intracellular bacterial viability while it increased IL-6 secretion by infected epithelial cells. These findings provide a new approach to prophylactic drying therapy that could help to improve conventional antimicrobial treatment against different forms of bacterial growth in an efficient, safer and greener manner reducing multiresistant bacteria generation and spread.

Advances in therapeutic and managemental approaches of bovine mastitis: a comprehensive review

“…Further research is required to evaluate the application of nanoparticles in mastitis therapy. Effect of combination of chitosan and cloxacillin on planktonic cultures, bacterial biofilms and intracellular growth in udder cells have been studied (Breser et al 2018 ). It was shown that combined approach of using chitosan and cloxacillin inhibited the formation of biofilm, improved clearance of already formed biofilm.…”

Nanoparticles for treatment of bovine Staphylococcus aureus mastitis

“…Furthermore, Shi et al (2016), demonstrated that chitosan-coated iron oxide compound nanoparticles are hindering the development of biofilm biomass and declining the quantity of live bacterium. A study reported by Breser et al (2018) showed that the combination between chitosan and cloxacillin combination inhibited biofilm formation and reduced intracellular viability of coagulase-negative Staphylococcus in cases of chronic mastitis. Chakraborty et al (2010) discussed that vancomycin loaded folic acid tagged chitosan nanoparticles had a higher bactericidal effect against vancomycin-resistant S. aureus by enhancing the transport of vancomycin across bacterial cell membranes.…”

Antimicrobial activity of polyhexamethylene biguanide nanoparticles against mastitis-causing Staphylococcus aureus

“…For these reasons, it was included in the formulation of the polymer-based NP evaluated in this study. It has been reported that the combination of chitosan and cloxacillin potentiated the antimicrobial activity against 7 CNS isolates from chronic mastitis cases (Breser et al, 2018). Moreover, Ashraf et al (2012) found that the growth curves of 1 Escherichia coli isolate were inhibited by PHMB functionalized silver NP at lower concentrations (0.075-0.15 μg/mL) than PHMB alone (3 μg/mL).…”