Department of Civil Engineering, University of Toledo, Toledo, OH 43606, USA.
FEMS Microbiol Ecol. 2013 Jan;83(1):101-11. doi: 10.1111/j.1574-6941.2012.01453.x. Epub 2012 Aug 8.
The reactivity of capsular extracellular polymeric substances (EPS) to chlorine and monochloramine was assessed and compared in this study. The impact of capsular EPS on Gram-negative bacteria Pseudomonas aeruginosa inactivation mechanisms was investigated both qualitatively and quantitatively using a combination of batch experiments, viability tests with LIVE/DEAD staining, and Fourier transform infrared spectroscopy (FTIR). Both wild-type and isogenic mutant strains with different alginate EPS production capabilities were used to evaluate their susceptibility to chlorine and monochloramine. The mucA22 mutant strain, which overproduces the EPS composed largely of acidic polysaccharide alginate, exhibited high resistance and prolonged inactivation time to both chlorine and monochloramine relative to PAO1 (wild-type) and algT(U) mutant strains (alginate EPS deficient). Multiple analyses were combined to better understand the mechanistic role of EPS against chlorine-based disinfectants. The extracted EPS exhibited high reactivity with chlorine and very low reactivity with monochloramine, suggesting different mechanism of protection against disinfectants. Moreover, capsular EPS on cell membrane appeared to reduce membrane permeabilization by disinfectants as suggested by deformation of key functional groups in EPS and cell membrane (the C-O-C stretching of carbohydrate and the C=O stretching of ester group). The combined results supported that capsular EPS, acting either as a disinfectant consumer (for chlorine inactivation) or limiting access to reactive sites on cell membrane (for monochloramine inactivation), provide a protective role for bacterial cells against regulatory residual disinfectants by reducing membrane permeabilization.
本研究评估并比较了荚膜细胞外聚合物物质（EPS）对氯和一氯胺的反应性。使用批处理实验、使用 LIVE/DEAD 染色进行的生存能力测试以及傅里叶变换红外光谱（FTIR）相结合，从定性和定量两个方面研究了荚膜 EPS 对革兰氏阴性细菌铜绿假单胞菌失活动力学的影响。使用具有不同藻酸盐 EPS 产生能力的野生型和同工酶突变菌株来评估它们对氯和一氯胺的敏感性。与 PAO1（野生型）和 algT(U)突变菌株（缺乏藻酸盐 EPS）相比，过度产生主要由酸性多糖藻酸盐组成的 EPS 的 mucA22 突变菌株对氯和一氯胺表现出高抗性和延长的失活动力学时间。结合多种分析方法更好地了解 EPS 对基于氯的消毒剂的机制作用。提取的 EPS 对氯表现出高反应性，对一氯胺反应性非常低，表明其对消毒剂的保护机制不同。此外，细胞膜上的荚膜 EPS 似乎通过改变 EPS 和细胞膜中关键官能团（碳水化合物的 C-O-C 伸缩和酯基的 C=O 伸缩）来减少消毒剂对膜通透性的破坏，从而减少消毒剂对膜通透性的破坏。细胞膜上的荚膜 EPS 似乎通过改变 EPS 和细胞膜中关键官能团（碳水化合物的 C-O-C 伸缩和酯基的 C=O 伸缩）来减少消毒剂对膜通透性的破坏，从而减少消毒剂对膜通透性的破坏。细胞膜上的荚膜 EPS 似乎通过改变 EPS 和细胞膜中关键官能团（碳水化合物的 C-O-C 伸缩和酯基的 C=O 伸缩）来减少消毒剂对膜通透性的破坏，从而减少消毒剂对膜通透性的破坏。
