Occurrence and molecular characterization of some zoonotic bacteria in bovine milk, milking equipments and humans in dairy farms, Sharkia, Egypt

One hundred bulk tank milk samples, 50 milking equipments’ swabs and 50 dairy workers’ hand swabs were collected from three dairy farms at Sharkia Province, Egypt, to determine the occurrence of some zoonotic bacteria as well as to investigate the presence of some virulence genes in all isolates by PCR. Staph. aureus, St. agalactiae, Salmonella species and M. bovis were isolated from milk samples with the percentages of 17%, 4%, 9% and 1%, respectively. In dairy workers hand swabs, the respective isolation rates of Staph. aureus, St. agalactia and Salmonellae were 10%, 2% and 8%, while only Staph. aureus and St. agalactiae were recovered from milking equipments (6%, each). Of the examined Staph. aureus isolates, 11.8% and 20% of milk and hand swabs’ isolates, respectively, were carrying sea gene. In St. agalactiae isolates, cfb virulence gene was identified in all the obtained isolates. Moreover, spvC virulence gene was detected in 40% and 33.3% of S. Typhimurium isolates recovered from milk and hand swabs’ samples, respectively. While the respective percentages of spvC gene identification in S. Enteritidis isolates from the same sources were 75% and 100%. M. bovis was isolated from 1% of milk samples only. In conclusion, the isolation of potentially virulent Staph. aureus, St. agalactia and Salmonellae in dairy farms is of public health significance to milk consumers. Although the low isolation rate, the detection of M. bovis in milk samples should be of great concern due to its high public health hazards.