Tubes containing swabs and BPW were gently mixed. For isolation of E. coli and Staphylococcus spp., 100 μL from each tube was streaked onto each of MacConkey, Sorbitol MacConkey, and Baird-Parker (Oxoid, UK), then incubated at 37 °C for 24 h. Lactose fermenting colonies on MacConkey agar, white colonies on Sorbitol MacConkey agar, and black colonies on Baird–Parker agar were identified biochemically to species level by VITEK® 2 COMPACT (BioMérieux, France). For isolation of Salmonella, tubes containing BPW were enriched overnight aerobically at 37 °C, then incubated on Rappaport-Vassiliadis broth (Oxoid, UK) at 42 °C in aerobic conditions for 24 h, before inoculation on to xylose lysine deoxycholate agar (Oxoid, UK) and incubated under aerobic conditions at 37 °C for 24 h. Suspected colonies were identified biochemically by VITEK® 2 COMPACT (BioMérieux, France). Biochemically identified Salmonella isolates have been serologically confirmed on the basis of somatic (O) and flagellar (H) antigens by slide agglutination using commercial antisera (SISIN, Germany) following the Kauffman–White scheme [53 (link)].
For molecular conformation, bacterial DNA was extracted from biochemically identified E. coli, Salmonella, and Staphylococcus isolates for amplification and sequencing of 16S rRNA gene according to Lane [54 ] and Weisberg et al. [55 (link)].
For molecular conformation, bacterial DNA was extracted from biochemically identified E. coli, Salmonella, and Staphylococcus isolates for amplification and sequencing of 16S rRNA gene according to Lane [54 ] and Weisberg et al. [55 (link)].