Identification, Molecular Detection and Antibiogram Profile of Bacteria Isolated from California Mastitis Test Positive Milk Samples of Crossbred Cows of Satkhira District in Bangladesh

Present study was conducted for the isolation, identification, molecular detection and antibiotic sensitivity patterns of the bacteria present in the California Mastitis Test (CMT) positive milk samples of clinical and sub-clinical mastitic crossbred (Friesian cross and Sahiwal cross) cows of Satkhira district. A total number of 598 quarters milk samples from 150 cows were tested by CMT kit, among them 82 quarters from 52 cows were positive for CMT. The bacteria isolated from 52 CMT positive milk samples were coagulase positive Staphylococcus aureus 27 (49.09%) followed by Escherichia coli 15 (27.27%), coagulase negative Staphylococcus (CNS) spp. 10 (18.18%) and Bacillus spp. 3 (5.45%) respectively. In this present study only 13 (48.15%) positive Staphylococcus aureus were positive against nuc gene by PCR. All the isolates of E.coli were further confirmed by PCR with species specific 16srRNA PCR. None of the isolates of E.coli revealed positivity in PCR by stx1 and stx2 genes. All the coagulase positive Staphylococcus aureus isolates were found sensitive to 6 antibiotics and resistant to 5 antibiotics. The Coagulase negative Staphylococcus spp. was also sensitive to 7 antibiotics and acquired resistant properties against 3 antibiotics. Most E.coli isolates were found resistant against 9 antibiotics already possessed multidrug resistant properties and sensitive to only 3 antibiotics. Bacillus spp. isolated from milk samples was highly sensitive against 5 antibiotics compare to other antibiotics of the panel. Antibiogram profile of this study revealed that, all the isolated bacteria were sensitive to Ciprofloxacin only