Nano antibiotics as an alternative therapy for drug resistant bacterial pathogens causing bovine mastitis

Abstract

A total of 1539 bovine milk samples were collected from six districts of North Eastern Tamil Nadu and Chennai. Based on the TANUCHECK SCC kit, subclinical and clinical mastitis positive milk together was 1086. From a total of 438 Staphylococcus spp isolated, 90 were coa+ve and 348 were coa-ve. A total of 260 Escherichia coli isolates were obtained from bovine mastitis milk. newlineBoth the Staphylococcus spp and Escherichia coli isolates were subjected to cultural and bio-chemical characterization. By the antibiotic sensitivity test, the phenotypic sensitivity / resistance pattern was recorded for 15 different antibiotics falling under five different drug class. newlineThe AST efficacy for drug conjugated Chitosan NPs was highest for Chitosan+Ampicillin (CHT+AMP)100% followed by Chitosan+Erythromycin (CHT+E) -75% and Tetracycline (CHT+TE) (38.88%) and (CHT+GEN) Gentamicin having (10.52%) lower action against the resistant E. coli isolates. newlineIrrespective of the resistant isolate used, the efficacy of antibiotics after conjugation with Chitosan was highest for Tetracycline (92.30%); followed by Ampicillin (66.66%); Erythromycin (46.15%) and Cefotaxime (40%). newlineIn comparison to both the nano particles, the antibiotic conjugated Chitosan NPs exhibited synergistic and higher antibacterial effect against the resistant isolates of both Staphylococcus spp and E. coli. The ZnO NPs conjugated antibiotics had lower efficacy towards the resistant bacterial isolates. newlineKey words: Bovine mastitis, Staphylococcus spp., Escherichia coli, abr genes, resisitant antibiotics, nano particles, ZnO NPs, Chitosan NPs. newline newline