Isolation of Salmonella strains from reptiles faeces and comparison of different culture media

Methods and Results: Ninety-one samples collected from reptiles of the zoo of Rome or belonging to private owners were analysed using a standard protocol for isolation of Salmonella from food. Salmonella strains were tested for susceptibility to 15 antimicrobics by a disc-agar diffusion method. Forty-six samples (50.5%) were positive for Salmonella. Of the 22 strains serotyped, 17 belonged to Salmonella enterica subsp. I, four to the subsp. IIIa and one strain resulted untypeable. Rappaport-Vassiliadis broth (RVB) allowed to recover more Salmonella strains when bacterial growth in buffered peptone water (BPW) was scarce, while selenite cystine broth (SCB) was more efficient, whereas growth in BPW was abundant. The maximum isolation score was obtained by plating onto xylose lysine desoxycholate agar (XLD). The strains exhibited resistance at high percentages to colistin sulphate (58.7%), sulphamethoxazole (55.5%), streptomycin (32.6%), tetracycline (19.6%), ampicillin (17.4%) and nalidixic acid (13.1%).