HiMedia – M2025 HiCrome™ Yersinia Agar Base

Principle and Interpretation
Yersinia enterocolitica is widely distributed in lakes and reservoirs ranging from intestinal tracts of numerous mammals. Environmental isolates are avirulent, however, isolates recovered from porcine sources contain human pathogens. Epizootic outbreaks of diarrhea, lymphadenopathy, pneumonia and spontaneous abortions occur in various animals due to these pathogenic serogroups. Y.enterocolitica is biochemically more active at room temperature than at 37°C. Yersinia Selective Agar Base with added Yersinia Selective Supplement is used to isolate Y.enterocolitica from clinical and food samples (3). Yersinia Selective Agar Base is recommended for selective isolation of Yersinia (1, 2) with modification of chromogenic identification . Peptone mix and growth factor provides nitrogen and carbon source, long chain amino acids, vitamins and other essential growth nutrients. The medium is selective due to the presence of selective mix, which inhibit gram-positive and a number of gram-negative bacteria. Addition of antibiotic supplement makes it highly selective for Yersinia,thus imparting additional selectivity. One of the chromogen is split by Yersinia species and results in purple coloured colonies. Other organisms are either inhibited or results in colourless colonies. For the isolation of Y. enterocolitica by direct plating and pour plating, inoculate the specimen directly onto the medium. Incubate at 22-32°C for 24-48 hours or suspend the sample (food, faeces, etc.) in sterile Phosphate Buffer Saline and incubate for upto 21 days (4) at 4°C. Klebsiella and Enterobacter species produces metallic blue colured colonies. Colonies of Proteus, Morganella and Providencia species appear brown .This medium can be employed in screening urinary tract pathogens wherein organisms can be differentiated based on colour and simultaneously the antibiotic sensitivity can be determined.

原理與解釋
小腸結腸炎耶爾森菌廣泛分佈在湖泊和水庫中，範圍來自許多哺乳動物的腸道。環境分離物是無毒的，然而，從豬源中回收的分離物含有人類病原體。由於這些致病性血清群，在各種動物中發生腹瀉，淋巴結病，肺炎和自發性流產的流行性暴發。 Y.enterocolitica在室溫下的生物化學活性比在37°C時更活躍。使用添加了耶爾森氏菌選擇性補充劑的耶爾森氏菌選擇性瓊脂基質從臨床和食品樣品中分離出Y.enterocolitica（3）。耶爾森氏菌選擇性瓊脂基質推薦用於選擇性分離耶爾森氏菌（1,2），並改變顯色鑑定。 蛋白腖混合和生長因子提供氮和碳源，長鏈氨基酸，維生素和其他必需的生長營養素。由於選擇性混合物的存在，培養基是選擇性的，其抑制革蘭氏陽性和許多革蘭氏陰性細菌。 添加抗生素補充劑使其對耶爾森氏菌具有高選擇性，從而賦予額外的選擇性。其中一種色原體被耶爾森氏菌分裂，產生紫色的菌落。其他生物被抑製或導致無色菌落。通過直接電鍍和澆注電鍍來分離Y. enterocolitica， 將標本直接接種到培養基上。在22-32°C孵育24-48小時或將樣品（食物，糞便等）懸浮在無菌磷酸鹽緩衝鹽水中，並在4°C下孵育長達21天（4）。