Périamé Marina, Pagès Jean-Marie, Davin-Regli Anne
UMR-MD-1, Aix-Marseille Université, IRBA, Transporteurs Membranaires, Chimiorésistance et Drug Design, Marseille, France.
J Appl Microbiol. 2015 Jan;118(1):49-61. doi: 10.1111/jam.12676. Epub 2014 Nov 25.
The objective of this study was to understand the adaptive mechanisms in Enterobacter gergoviae which are involved in recurrent contaminations in cosmetic products that are incorporated with preservatives.
Bacterial strains from two backgrounds were examined for a profound understanding of the mechanisms of adaptation against preservatives. It included a series of Ent. gergoviae strain-ATCC 33028 derivatives, isolated using increasing methylisothiazolinone-chloromethylisothiazolinone (MIT-CMIT) and triclosan concentrations. The other series was of Ent. gergoviae isolates from cosmetic products exhibiting MIT-CMIT and triclosan resistance. We evaluated the outer membrane protein modifications and efflux mechanisms activities responsible for the resistant trait via immunoblotting assays. Additionally, for understanding the efflux activity real-time efflux, experiments were performed. A cross-insusceptibility between preservatives and some disinfectants was observed in MIT-CMIT-resistant derivative isolates, but antibiotics susceptibility was not altered. Resistance to EDTA was significant in all preservatives insusceptible derivative strains, indicating modifications in the LPS layer. Furthermore, an array of real-time efflux assays indicated different activity levels while no variations were detected in porins and AcrAB-TolC pumps production. Overexpression of a specific flagellin-type protein was observed in one of the MIT-CMIT- and triclosan-resistant strains. Another candidate, a 25-kDa peroxiredoxin enzyme involved in oxidative detoxification, was identified to be overexpressed in MIT-CMIT derivative. A similar profile was also observed among strains isolated from cosmetic products.
Our study highlights the existence of adaptive mechanisms such as overexpression of detoxifying enzymes, flagellin, modification of membrane structure/function in Ent. gergoviae. They might be involved in recurrent episodes of contaminations occurring in the cosmetic production lines.
No cross-resistance could be observed with antibiotics when MICs to preservatives were increased; however, a decrease in the disinfectants bactericidal effects was confirmed in preservative-tolerant strains. This will impact industry disinfection strategies treatment against bacteria.
本研究的目的是了解格氏肠杆菌中参与含防腐剂化妆品反复污染的适应性机制。
对来自两种背景的细菌菌株进行检测，以深入了解其对防腐剂的适应机制。其中包括一系列格氏肠杆菌菌株——ATCC 33028衍生物，这些菌株是使用浓度递增的甲基异噻唑啉酮 - 氯甲基异噻唑啉酮（MIT - CMIT）和三氯生分离得到的。另一系列是从表现出对MIT - CMIT和三氯生耐药的化妆品中分离出的格氏肠杆菌菌株。我们通过免疫印迹分析评估了负责耐药性状的外膜蛋白修饰和外排机制活性。此外，为了解外排活性，进行了实时外排实验。在对MIT - CMIT耐药的衍生物分离株中观察到防腐剂与一些消毒剂之间存在交叉不敏感性，但抗生素敏感性未改变。在所有对防腐剂不敏感的衍生物菌株中，对EDTA的耐药性显著，表明脂多糖层发生了修饰。此外，一系列实时外排实验表明活性水平不同，而孔蛋白和AcrAB - TolC泵的产生未检测到变化。在一株对MIT - CMIT和三氯生耐药的菌株中观察到一种特定鞭毛蛋白型蛋白的过表达。另一个候选蛋白，一种参与氧化解毒的25 kDa过氧化物酶，被鉴定在MIT - CMIT衍生物中过表达。从化妆品中分离出的菌株中也观察到类似的情况。
我们的研究突出了格氏肠杆菌中存在适应性机制，如解毒酶过表达、鞭毛蛋白、膜结构/功能修饰。它们可能与化妆品生产线中反复出现的污染事件有关。
当对防腐剂的最低抑菌浓度增加时，未观察到与抗生素的交叉耐药性；然而，在耐防腐剂菌株中证实了消毒剂杀菌效果的降低。这将影响针对细菌的工业消毒策略治疗。
