Product Code TM 039
The Salmonellae constitute the most taxonomically complex group of bacteria among Enterobacteriaceae. Human Salmonella infections are most commonly caused by ingestion of food, water or milk contaminated by human or animal excreta. Humans are the only reservoirs of S. Typhi. Four clinical types of Salmonella infections may be distinguished namely gastroenteritis, bacteremia or septicemia, enteric fever and a carrier state. Of the various media employed for theisolation and preliminary identification of Salmonellae, particularly Salmonella Typhi; Bismuth Sulphite Agar is the most productive. Bismuth Sulphite Agar is a modification of original Wilson and Blair Medium. It is also recommended by various Associations for the isolation and preliminary identification of Salmonella Typhi and other Salmonellae from pathological materials, sewage, water, food and other products. S.Typhi, S. Enteritidis and S. Typhimurium typically grow as black colonies with a surrounding metallic sheen resulting from hydrogen sulphide production and reduction of sulphite to black ferric sulphide. Salmonella Paratyphi A grows as light green colonies. Bismuth Sulphite Agar may be inhibitory to some strains of Salmonella species and therefore should not be used as the sole selective medium for these organisms. Also this medium favors use of larger inoculum as compared to other selective media, as it has unique inhibitory action towards gram-positive organisms and coliforms.
for selective isolation of Salmonellae from faeces, urine, sewage and other materials