Graduate Program in Pharmaceutical Sciences, Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil.
Am J Infect Control. 2013 Dec;41(12):e119-22. doi: 10.1016/j.ajic.2013.05.002. Epub 2013 Aug 1.
A biofilm is a complex microbiological ecosystem deposited on surfaces. Microorganisms in form of biofilms are of particular clinical concern because of the poor response to antimicrobial treatments. This study aimed to determine whether bacterial and fungal biofilms are able to resist the antimicrobial activity of chlorhexidine, a powerful antiseptic widely used in the hospital environment.
Disk diffusion and susceptibility tests were conducted in accordance with Clinical and Laboratory Standards Institute standards for the determination of biofilm inhibitory concentration. Chlorhexidine was tested first at a minimum inhibitory concentration and then at higher concentrations when it was not able to destroy the biofilm. The plates were developed with a solution of 0.1% crystal violet, and readings were made at an optical density of 570 nm.
Chlorhexidine demonstrated excellent antimicrobial activity for most microorganisms tested in their free form, but was less effective against biofilms of Acinetobacter baumannii, Escherichia coli, methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa.
This study confirms that microorganisms in biofilms have greater resistance to chlorhexidine, likely owing to the mechanisms of resistance conferred to the structure of biofilms.
生物膜是一种沉积在表面的复杂微生物生态系统。以生物膜形式存在的微生物尤其受到临床关注，因为它们对抗菌治疗的反应较差。本研究旨在确定细菌和真菌生物膜是否能够抵抗洗必泰的抗菌活性，洗必泰是一种在医院环境中广泛使用的强力防腐剂。
根据临床和实验室标准协会标准进行了圆盘扩散和药敏试验，以确定生物膜抑制浓度。首先在最小抑菌浓度下测试洗必泰，然后在洗必泰不能破坏生物膜时测试更高浓度。用 0.1%结晶紫溶液对平板进行显色，在 570nm 光密度下读数。
洗必泰对大多数测试的游离形式的微生物表现出极好的抗菌活性，但对鲍曼不动杆菌、大肠杆菌、耐甲氧西林金黄色葡萄球菌和铜绿假单胞菌的生物膜的效果较差。
本研究证实，生物膜中的微生物对洗必泰具有更强的抵抗力，这可能归因于赋予生物膜结构的耐药机制。
