Jones D S, McGovern J G, Woolfson A D, Gorman S P
Pharmaceutical Devices Research Group, School of Pharmacy, Queen's University of Belfast, Northern Ireland, UK.
Biomaterials. 1997 Mar;18(6):503-10. doi: 10.1016/s0142-9612(96)00170-6.
Pneumonia is a major problem in intensive care patients and can be induced by pathogenic bacteria adhering to poly(vinyl chloride) (PVC) endotracheal (ET) tubes. This study examines the influence of surface properties on the adherence of the respiratory isolates Staphylococcus aureus and Pseudomonas aeruginosa to PVC. In particular, the influence of respiratory tract physiological conditions, 5% CO2 and saliva, on adherence was investigated. In general, decreased adherence to PVC was observed when bacteria were grown in CO2. When these CO2-grown bacteria were treated with saliva their adherence to PVC significantly increased; however, their adherence was significantly reduced to saliva-treated PVC. Treatment of both bacterial isolates with saliva decreased their negative zeta potential, a factor which may directly contribute to the observed increased microbial (saliva pretreated) adherence to PVC. Cell surface hydrophobicity (CSH) was evaluated by measuring the initial rates of microbial removal from a buffered aqueous phase, to ensure the absence of electrostatic interactions, to an organic phase (xylene). Under physiological conditions, CSH did not appear to be a dominant factor in biomaterial adherence as the CSH of S. aureus was decreased by saliva treatment but was unchanged for Ps. aeruginosa. Additionally, CSH also differed for the two isolates when grown in CO2, significantly decreasing with S. aureus but remaining unaltered with Ps. aeruginosa. Saliva treatment of PVC also decreased the advancing and receding contact angles of the biomaterial and its surface roughness, which may be a factor in the decreased adherence of saliva-treated bacteria to this surface. Alternative biomaterials or surface modifications appear necessary for the desired improvements in ET tube effectiveness. This study highlights the influence of physiological conditions on biomaterial and bacterial surface characteristics and subsequent interactions. It is imperative that the physiological conditions predominating in the clinical area of biomaterial use be considered when investigating device biocompatibility.
肺炎是重症监护患者面临的一个主要问题，可由病原菌附着于聚氯乙烯（PVC）气管内（ET）导管引发。本研究考察了表面性质对呼吸道分离菌金黄色葡萄球菌和铜绿假单胞菌附着于PVC的影响。特别研究了呼吸道生理条件、5%二氧化碳和唾液对附着的影响。总体而言，当细菌在二氧化碳环境中生长时，观察到其对PVC的附着减少。当这些在二氧化碳环境中生长的细菌用唾液处理后，它们对PVC的附着显著增加；然而，它们对经唾液处理的PVC的附着显著降低。用唾液处理这两种细菌分离株均降低了其负ζ电位，这一因素可能直接导致观察到的微生物（经唾液预处理）对PVC附着增加。通过测量微生物从缓冲水相到有机相（二甲苯）的初始去除速率来评估细胞表面疏水性（CSH），以确保不存在静电相互作用。在生理条件下，CSH似乎不是生物材料附着的主导因素，因为唾液处理使金黄色葡萄球菌的CSH降低，但铜绿假单胞菌的CSH未改变。此外，当在二氧化碳环境中生长时，这两种分离株的CSH也不同，金黄色葡萄球菌的CSH显著降低，而铜绿假单胞菌的CSH保持不变。用唾液处理PVC也降低了生物材料的前进和后退接触角及其表面粗糙度，这可能是经唾液处理的细菌对该表面附着减少的一个因素。为了实现ET导管有效性的预期改善，似乎需要替代生物材料或表面改性。本研究强调了生理条件对生物材料和细菌表面特性以及后续相互作用的影响。在研究器械生物相容性时，必须考虑生物材料临床使用领域中占主导地位的生理条件。
