Brill Florian, Goroncy-Bermes Peter, Sand Wolfgang
Microbiology Department, University of Hamburg, Biocentre Klein Flottbek and Botanical Garden, Ohnhorststrasse 18, 22609 Hamburg, Germany.
Int J Hyg Environ Health. 2006 Jan;209(1):89-95. doi: 10.1016/j.ijheh.2005.08.007. Epub 2005 Nov 9.
In this study, the influence of culturing Staphylococcus aureus and Pseudomonas aeruginosa under different growth conditions on their inactivation by the cationic active compounds benzalkonium chloride, chlorhexidine digluconate and octenidine dihydrochloride was investigated. Cells were grown in non-agitated tryptone soya broth as well as on tryptone soya agar according to national and international standards for evaluating chemical disinfectants. In quantitative suspension tests, cells of both test organisms grown on agar were significantly more sensitive to all three biocides than cells grown in broth. The differences in antimicrobial activity were greater in the case of S. aureus than in the case of P. aeruginosa. With S. aureus cultures, differences in the reduction factor of up to 5 log steps were found, with P. aeruginosa up to 2.5 log steps. The results of our uptake tests performed with S. aureus and octenidine dihydrochloride indicated that the growth conditions and the associated different stress factors either had an influence on the composition of the cell surface of this test organism or induced the formation of an efflux system. Cells of S. aureus cultured in broth took up only one-fifth of the amount of biocide molecules compared to cells from agar cultures. These data correlated with the results of the suspension tests. A low uptake of biocides apparently led to a reduced killing rate. In contrast to S. aureus, no significant differences in the uptake of octenidine dihydrochloride by cells of P. aeruginosa could be observed. These cells took up the same amount of the antimicrobial substance, whether on agar or in broth. In view of these results, possible consequences should be considered prior to changing test regulations.
在本研究中，研究了在不同生长条件下培养金黄色葡萄球菌和铜绿假单胞菌对其被阳离子活性化合物苯扎氯铵、葡萄糖酸洗必泰和盐酸奥替尼啶灭活的影响。根据评估化学消毒剂的国家和国际标准，细胞在未搅拌的胰蛋白胨大豆肉汤以及胰蛋白胨大豆琼脂上生长。在定量悬液试验中，两种受试微生物在琼脂上生长的细胞对所有三种杀菌剂的敏感性均显著高于在肉汤中生长的细胞。金黄色葡萄球菌的抗菌活性差异比铜绿假单胞菌的更大。对于金黄色葡萄球菌培养物，发现还原因子的差异高达5个对数级，对于铜绿假单胞菌则高达2.5个对数级。我们用金黄色葡萄球菌和盐酸奥替尼啶进行的摄取试验结果表明，生长条件和相关的不同应激因素要么对该受试微生物的细胞表面组成有影响，要么诱导了外排系统的形成。与琼脂培养的细胞相比，在肉汤中培养的金黄色葡萄球菌细胞摄取的杀菌剂分子数量仅为其五分之一。这些数据与悬液试验结果相关。杀菌剂摄取量低显然导致杀灭率降低。与金黄色葡萄球菌不同，未观察到铜绿假单胞菌细胞对盐酸奥替尼啶的摄取有显著差异。无论在琼脂上还是在肉汤中，这些细胞摄取的抗菌物质数量相同。鉴于这些结果，在改变试验规定之前应考虑可能的后果。
