Department of Preventive Medicine and Public Health, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, Granada, Spain.
Lett Appl Microbiol. 2013 Dec;57(6):517-25. doi: 10.1111/lam.12142. Epub 2013 Aug 27.
One of the most commonly used methods for assessing disinfectants in vitro is the dilution-neutralization test. Although it is known that using an effective neutralizer is essential for obtaining reliable results, in the case of disinfectants like triclosan, whose neutralization is more complicated, an adequate neutralizer is not always used. Here, we compare the efficacy of different neutralizers described previously, and others that have been modified, against several antiseptic formulations of triclosan. The strains of reference used were Pseudomonas aeruginosa, Enterococcus faecium, Staphylococcus aureus and Escherichia coli. The solutions of antiseptic were triclosan 2% aqueous solution, and three alcoholic solutions containing 2, 0·068 and 0·5% triclosan, respectively. In the dilution-neutralization test, six neutralizers with different degrees of complexity were assayed. Our results show that the antiseptic solutions studied are effective against the strains of reference, with the exception of triclosan 2% aqueous solution against Ps. aeruginosa. Most neutralizers proved ineffective, depending on the antiseptic solution and the bacterial species, particularly in the case of Staph. aureus. These findings confirm a need to test every neutralizer specifically for each disinfectant, at the maximum concentration used, and for every specific bacterial strain.
The choice of an adequate neutralizing agent is essential for obtaining precise results in the evaluation of disinfectants using the dilution-neutralization method. In this study, we show that the neutralization of triclosan and some of its commercial solutions is not a simple task, requiring complex neutralizers. Moreover, the action of the neutralizer is shown to depend on the micro-organism tested. Specificity in view of the disinfectant and the micro-organism calls for performing the neutralizing assay in each particular case of application of the dilution-neutralization method. We also demonstrate that some of the neutralizers described for triclosan in previous studies are not sufficiently effective.
体外评估消毒剂最常用的方法之一是稀释中和试验。虽然众所周知，使用有效的中和剂对于获得可靠的结果至关重要，但在三氯生等中和更为复杂的消毒剂的情况下，并不总是使用适当的中和剂。在这里，我们比较了之前描述的不同中和剂的功效，以及其他经过改良的中和剂，针对几种三氯生的抗菌制剂。参考菌株使用的是铜绿假单胞菌、屎肠球菌、金黄色葡萄球菌和大肠杆菌。抗菌溶液为 2%三氯生水溶液，以及分别含有 2%、0.068%和 0.5%三氯生的三种酒精溶液。在稀释中和试验中，测试了六种具有不同复杂程度的中和剂。我们的结果表明，研究中使用的抗菌溶液对参考菌株有效，除了 2%三氯生水溶液对铜绿假单胞菌无效。大多数中和剂都证明无效，这取决于抗菌溶液和细菌种类，尤其是金黄色葡萄球菌。这些发现证实，在使用稀释中和法评估消毒剂时，需要针对每种消毒剂和每种特定细菌菌株，在最大使用浓度下具体测试每种中和剂。
