2,3,5-三苯基氯化四氮对菌落计数的影响研究

Studies on influence of TTC in Colony Counting

目的判定不同浓度2,3,5-三苯基氯化四氮(TTC)对大肠埃希菌、铜绿假单胞菌菌落、金黄色葡萄球菌总数的影响。方法采用平皿计数法对不同TTC浓度的菌液进行细菌菌落总数计数的回收率试验。以0.9%的氯化钠作空白对照,观察细菌在不同浓度TTC的琼脂培养基中(每1mL相应浓度TTC于每100mL营养琼脂中)生长的差异。结果加TTC实验组的菌落均出现不同程度的红色。TTC对革兰阳性菌代表菌株金黄色葡萄球菌有抑制作用,浓度越高抑制作用越明显。对革兰氏阴性菌则不敏感,几乎不出现抑制作用。结论应用TTC作为指示剂进行菌落计数时,会造成一定程度上检测结果的误差,微生物工作者在进行菌落总数测定时应引起注意。

OBJECTIVE To determine the influence of different concentrations of TTC nutrition AGAR medium on total microbial count of escheriehia toll, staphylococcus aureus and pseudomonas aeruginosa. METHODS Using plate counting method to study the recovery of bacterial liquid containing concentration gradient of TTC. Growing difference of bacteria in various Trc concentration agar medium were observed with 0. 9% NaCI as blank con- trast. RESULTS The bacterial colonies adding TTC showed various degree of red. TTC inhibit staphylococcus au- reus which was a gram-positive bacterium. The higher the concentration was, the more obvious inhibitory effect was. TTC had no inhibitory effect on gram-negative bacterium. CONCLUSION Using TTC as indicator in colony counting brings errors in results which should be paid more attention by microbial staff.