Triple sugar iron

Sodium chloride (NaCl) was purchased from Sigma-Aldrich (St. Louis, MO, United States). Brain Heart Infusion (BHI) broth, Müller Hinton Agar (MHA), Blood Agar (BA), Eosin Methylene Blue Agar (EMB Agar), MacConkey Agar (MAC), Triple Sugar Iron (TSI), and TBE buffer were purchased from Merck Co., Germany). Antibiotic discs were purchased from Mast Company (MASTDISCS combi-D73C, Bootle, UK). Standard strains of Pseudomonas aeruginosa ATTC 27853, E. coli ATTC 25922 bacteria, and K. pneumoniae ATCC 700603 were purchased from Pasteur Institute (Tehran, Iran).

The Salmonella isolation procedure was used as per the method of Waltman et al. (1993) (link). The swabs were inoculated in pre-enrichment media (peptone water, Oxoid, Hampshire, UK) at 35°C–37°C for 24 hours. A loopful of the pre-enrichment medium was then inoculated in the selective-enrichment broth, Rappaport Vassiliadis (Oxoid, Hampshire, UK) at 35°C–37°C for 24 hours after collection. A loopful of the selective-enrichment broth was then streaked on the selective media, xylose lysine desoxycholate (Oxoid, Hampshire, United Kingdom) agar at 35°C–37°C for 24 hours. The morphology of the bacteria was tested by Gram stain. The isolates were then identified biochemically using a single colony selected and inoculated in triple sugar iron (Merck, Darmstadt, Germany) agar, citrate, lysine, indol, urea, and oxidase (Merck, Darmstadt, Germany). The positive colony was submitted to the National Centre for Animal Health for serotyping using slide agglutinations O1, O9, O12, and H including [f], g, m, and [p]antigens.