[Prevalence of Listeria spp. in dairy farm and evaluation of antibiotic-resistance of isolates].

The study was performed to estimate the prevalence and antimicrobial sensitivities of Listeria spp. in raw milk, feaces end environmental samples isolated from 10 dairy in Molise Region. A total of 454 samples were collected, which comprised 40 raw milk, 40 animal faeces and 374 environmental samples. Listeria monocytogenes was never isolated from raw milk specimens; one was isolated from faeces speciments and two were isolated from environmental samples. All isolates were resistant to two or more of antimicrobial agents tested (cephalotin, ampicillin, tetracycline, co-trimoxazole, erytromicin, clindamycin, gentamicin, oxacillin). One isolate of L. monocytogenes was susceptible to all antimicrobial agents tested except oxacillin. This study indicates that faeces, equipments and environment are important reservoirs of Listeria spp. in dairy farm, and can represent potential source of contamination of raw milk. However, the contamination of milk, and the risk of infection, can be effectively eliminated by pasteurisation process.