spp. in bovine milk: An emerging pathogen with potential zoonotic risk.

The aim of the present study was to assess the prevalence and genetic characteristics of spp. in bovine bulk tank milk produced in Apulia Region (Italy). Samples collected from 396 dairy farms, after enrichment in a selective broth, were subjected to an genus - specific Real Time PCR. Positive broths, previously filtered, were seeded on Karmali, MCCD and Columbia Blood Agar plates; presumptive spp. colonies were identified using an amplification and sequencing method and then characterized by Multi-Locus Sequence Typing (MLST). Prevalence of spp in bovine milk samples was 5% (20/396); was the only isolated species, in agreement with previous studies that reported as the most commonly recovered species in milk and dairy products. MLST analysis of the 20 strains identified 81 alleles and 16 STs. Consistent with previous studies, MLST revealed a high level of heterogeneity between the isolates and confirmed the high discriminatory power of this method and its suitability for epidemiological investigations. This study confirmed the importance of raw milk as a possible source of spp for humans.