Molecular identification of bacteria isolated from dairy herds with mastitis.

Abstract

Summary The purpose of the present study was to identify environmental and contagious aerobic pathogen agents causing bovine clinical and subclinical mastitis using sequencing. A total of 244 cows were studied for the presence of mastitis using California Mastitis Test (CMT), clinical observations and microbiological isolations. Milk samples were obtained from 226 quarters of 123 cows which were diagnosed having clinical (11.4%) and subclinical (88.6%) mastitis. From these milk samples, 38 (16.8%) had no bacterial growth and from remaining 188 samples (83.2%) microorganisms were isolated. A total of 42 species were identified by sequencing amplified 16S rRNA fragments. The most common species were Staphylococcus aureus (22.9%) followed by Escherichia coli (10.1%), S. chromogenes (8.5%), S. haemoliticus (7.5%) and Hafnia alvei (6.4%). Of 188 isolates 43 were found contagious (22.9%), and 145 (77.1%) environmental agents. Use of sequencing offer identification of aetiological agent species level useful and practical that can help to chose a suitable therapeutic agent.