ISOLATION, CHARACTERIZATION AND IDENTIFICATION OF MULTI-DRUG RESISTANT SHIGELLA FLEXNERI, MAMMALIICOCCUS SCIURI AND ENTEROCOCCUS GALLINARUM FROM BOVINE MASTITIS AND SHIGELLOSIS CASES IN WESTERN MAHARASHTRA, INDIA

Abstract

Bovine mastitis and shigellosis-like enteric infections remain major constraints on dairy productivity and animal health, and are increasingly associated with multidrug-resistant (MDR) bacterial pathogens that threaten both veterinary therapeutics and human health via food chain. This study aimed to isolate, characterize and molecularly identify MDR bacterial pathogens from mastitis and shigellosis-suspected dairy cattle across three talukas of western Maharashtra from India including Baramati, Newasa, and Shevgaon. Twenty-five clinical samples (milk and blood) were collected from mastitis and shigellosis suspected cows, with matched samples from healthy cows as morphotype controls. Following peptone-broth enrichment and comparative spread-plating on tryptone blood agar, sixteen distinct isolates were recovered and screened for antibiotic susceptibility against 20 antibiotics using a modified Kirby–Bauer disc diffusion method. Isolates resistant to six or more antibiotics were classified as MDR. Of sixteen isolates screened, three isolates- one from shigellosis-infected milk, one from mastitis-infected milk, and one from mastitis-infected blood met MDR criteria. Biochemical profiling using the VITEK 2 system, 16S rRNA sequencing and BLASTn identified the three MDR isolates as Shigella flexneri (isolate MM1; 99.51% identity to strain ATCC 29903), Mammaliicoccus sciuri (isolate MM2; 100.00% identity to strain DSM 20345), and Enterococcus gallinarum (isolate B3; 99.92% identity to strain NBRC 100675).