HiMedia – M1842 HiCrome™ Selective Salmonella Agar Base

Principle and Interpretation
Salmonella species have been isolated from humans and almost all　animals throughout the world. They cause many types of infections　from mild, self-limiting gastroenteritis to life threatening typhoid fever. Salmonella Typhi and Salmonella Paratyphi A & B cause gastroenteritis,bacteremia and enteric fever, Salmonella Choleraesuis causes gastroenteritis and enteric fever, especially in children. Salmonella Typhimurium is the most frequently isolated serotype of Salmonella. Salmonella species are the major cause of food poisoning (1) Various chromogenic media are available for the differentiation of Salmonella species. The original media formulated by Rambach (2) differentiates Salmonella based on propylene glycol utilization Enterobacter and presence of a chromogenic indicator. However HiCrome™ Selective Salmonella Agar Base uses chromogenic mixture for identification and differentiation of Salmonella species. Sodium cholate, Sodium taurocholate and Sodium deoxycholate in the medium helps to restrict the growth of other organisms. Besides the selective supplement added to the medium inhibits competing microorganisms. HI powder, yeast hydrolysate and tryptose in the medium provides nitrogenous, carbonaceous compounds, long chain amino acids, vitamins and other essential growth nutrients. Due to the presence of chromogenic mix in the medium Salmonella are easily distinguishable and forms purple coloured colonies while some Enterobacteriaceae like Klebsiella and Enterobacter forms blue to dark blue coloured colonies. Conventional method employes the H2S production property for Salmonella detection which is also exhibited by other non Salmonella species such as Citrobacter, Proteus, etc. Hence further biochemical confirmation is required for further identification. This medium is specially employed for food samples where the sample is initially enriched in Salmonella Selective Enrichment Broth (M1843) and then isolated on HiCrome™ Selective SalmonellaAgar Base. Salmonella species give purple coloured colonies due to the enzyme specificity.

原理與解釋
沙門氏菌已從人類和世界各地的幾乎所有動物中分離出來。它們引起多種類型的感染，從輕度，自限性胃腸炎到危及生命的傷寒。 傷寒沙門氏菌和副傷寒沙門氏菌A和B引起腸胃炎，菌血症和腸炎，霍亂沙門氏菌引起胃腸炎和腸熱，尤其是兒童。鼠傷寒沙門氏菌是最常分離的沙門氏菌血清型。 沙門氏菌是食物中毒的主要原因（1）各種顯色培養基可用於分化沙門氏菌。由Rambach（2）制定的原始培養基根據丙二醇利用腸桿菌和存在顯色指示劑來區分沙門氏菌。然而，HiCrome™選擇性沙門氏菌瓊脂基質使用顯色混合物來鑑定和分化沙門氏菌。培養基中的膽酸鈉，牛磺膽酸鈉和脫氧膽酸鈉有助於限制其他生物的生長。除了添加到培養基中的選擇性補充劑抑制競爭性微生物。 HI粉末，酵母水解產物和胰蛋白酶在培養基中提供含氮，含碳化合物，長鏈氨基酸，維生素和其他必需的生長營養素。由於在培養基中存在生色混合物，沙門氏菌很容易區分並形成紫色的菌落，而一些腸桿菌科如克雷伯氏菌和腸桿菌形成藍色至深藍色的菌落。 常規方法利用H2S生產特性進行沙門氏菌檢測，其也由其他非沙門氏菌物種如檸檬酸桿菌，變形桿菌等表現出來。因此需要進一步的生物化學確認以進一步鑑定。 該培養基專門用於食品樣品，其中樣品最初富含沙門氏菌選擇性富集培養液（M1843），然後在HiCrome™選擇性沙門氏菌阿加鹼基上分離。由於酶的特異性，沙門氏菌物種會產生紫色的菌落。