Peterson L R, Kelly P J, Nordbrock H A
Department of Pathology, Northwestern Memorial Hospital, Chicago, Illinois 60611, USA.
Eur J Clin Microbiol Infect Dis. 1996 Apr;15(4):330-6. doi: 10.1007/BF01695667.
Two variations of an egg yolk agar base medium containing cycloserine, cefoxitin, and fructose (CCFA), one with 250 micrograms and other with 500 micrograms of cycloserine/ml of agar medium were compared to study the effect of the cycloserine concentration on recovery of Clostridium difficile from stool samples. In addition, the role of prior anaerobic reduction of these media in the detection of Clostridium difficile-associated diarrhea (CDAD) was tested. Each medium was studied over a two-month period, with outcome compared between the testing periods and to historical data from our institution. Clinical correlation of test results was performed. The use of the originally described formulation of CCFA with 500 microgram of cycloserine/ml of agar combined with 4 h of anaerobic reduction prior to specimen inoculation increased the rate of isolation of toxigenic Clostridium difficile from clinical specimens from 6 to 17% (p < 0.001). Combining direct detection of stool toxin and properly performed culture for toxigenic Clostridium difficile enhances the potential for diagnosis of CDAD. For optimal performance the culture medium should contain the originally proposed cycloserine concentration of 500 microgram/ml of agar and should be anaerobically reduced at least 4 h prior to specimen inoculation.
比较了含有环丝氨酸、头孢西丁和果糖（CCFA）的蛋黄琼脂基础培养基的两种变体，一种每毫升琼脂培养基含250微克环丝氨酸，另一种含500微克环丝氨酸，以研究环丝氨酸浓度对从粪便样本中分离艰难梭菌的影响。此外，还测试了这些培养基预先进行厌氧还原在艰难梭菌相关性腹泻（CDAD）检测中的作用。每种培养基研究两个月，比较测试期间的结果以及与本机构的历史数据。对检测结果进行临床相关性分析。使用最初描述的每毫升琼脂含500微克环丝氨酸的CCFA配方，并在接种标本前进行4小时厌氧还原，可使临床标本中产毒艰难梭菌的分离率从6%提高到17%（p<0.001）。结合粪便毒素的直接检测和对产毒艰难梭菌进行正确的培养，可提高CDAD的诊断潜力。为实现最佳性能，培养基应含有最初建议的每毫升琼脂500微克环丝氨酸的浓度，并且应在接种标本前至少进行4小时厌氧还原。
