Watkins J, Sartory D P
CREH Analytical, Horsforth, Leeds, UK.
Lett Appl Microbiol. 2015 Apr;60(4):367-71. doi: 10.1111/lam.12383. Epub 2015 Jan 15.
A modification of the UK reference and ISO 14189 TSCA medium for the enumeration of Clostridium perfringens from water coupled with a membrane filter transfer technique for testing for production of acid phosphatase was evaluated. The new tryptose cycloserine agar (TCA) medium, which lacks sodium metabisulphite but contains sodium pyruvate to improve recovery, allows the isolation and confirmation of Cl. perfringens within 18-24 h of sample processing. Data from a multilaboratory study analysed according to ISO 17994 showed that TCA was equivalent to TSCA for the enumeration of Cl. perfringens. The identification of acid phosphatase-negative isolates revealed a false-negative rate for the TCA method of 0.8%. The TCA membrane filter transfer procedure provides confirmed Cl. perfringens counts in half the time of the TSCA method and is simple to undertake.
The testing of drinking water for Clostridium perfringens is a regulatory parameter in Europe and the UK. Current UK and ISO methods employ membrane filtration (MF) and TSCA medium followed by subculture and confirmation of isolates by testing for acid phosphatase. This takes 48 h. We present here the results of a multilaboratory evaluation of a MF method that features a simplified isolation medium (TCA) and a membrane transfer procedure for the acid phosphatase test resulting in confirmed results being available in 18-24 h. This development significantly reduces the time to confirmed results for Cl. perfringens from water samples.
评估了一种对英国参考培养基和ISO 14189 TSCA培养基的改良方法，用于从水中计数产气荚膜梭菌，并结合膜过滤转移技术检测酸性磷酸酶的产生。新的胰蛋白胨环丝氨酸琼脂（TCA）培养基缺乏焦亚硫酸钠但含有丙酮酸钠以提高回收率，可在样品处理后的18 - 24小时内分离并确认产气荚膜梭菌。根据ISO 17994进行分析的多实验室研究数据表明，TCA在产气荚膜梭菌计数方面与TSCA相当。对酸性磷酸酶阴性分离株的鉴定显示，TCA方法的假阴性率为0.8%。TCA膜过滤转移程序可在TSCA方法一半的时间内提供经确认的产气荚膜梭菌计数，且操作简单。
在欧洲和英国，对饮用水中的产气荚膜梭菌进行检测是一项监管参数。目前英国和ISO方法采用膜过滤（MF）和TSCA培养基，随后进行传代培养，并通过检测酸性磷酸酶来确认分离株，这需要48小时。我们在此展示了一种MF方法的多实验室评估结果，该方法采用简化的分离培养基（TCA）和用于酸性磷酸酶检测的膜转移程序，可在18 - 24小时内获得经确认的结果。这一进展显著缩短了从水样中获得产气荚膜梭菌确认结果的时间。
