Percival Steven L, Bowler Phillip G, Dolman Jayne
ConvaTec Wound Therapeutics, Global Development Centre, Deeside Industrial Park, Deeside, Flintshire, UK.
Int Wound J. 2007 Jun;4(2):186-91. doi: 10.1111/j.1742-481X.2007.00296.x.
Antimicrobial dressings such as those containing silver are now being used widely to control wound bioburden, and tests to demonstrate their efficacy predominantly involve in vitro models using free-living or planktonic bacteria. In this present study a wide range of antibiotic-sensitive and resistant bacteria were tested in their quasi-sessile state using a standard agar assay and a second method used a poloxamer gel (true biofilm state - poloxamer encourages microorganisms to exhibit a more clinically relevant biofilm phenotype) technique. The antimicrobial activity of two silver dressings, a silver-containing Hydrofiber (SCH) dressing and a nanocrystalline silver-containing dressing (NCS), were evaluated on a variety of microorganisms, using a zone-of-inhibition (ZOI) test. When grown on agar (presenting a quasi-sessile state of each organism), the antibiotic-susceptible microorganisms were generally more susceptible to the SCH dressing compared with the NCS. ZOIs associated with SCH dressing ranged between 5.7 and 17.5 mm; those for the NCS against the same group of organisms ranged between 1.9 and 8.6 mm. When grown on poloxamer gel, (presenting the biofilm state of each organism) the same group of microorganisms were less susceptible to both dressings. The SCH dressing was most effective against strains of Pseudomonas aeruginosa, Candida albicans and Staphylococcus aureus (ZOI range: 2.6-6 mm); the NCS was most effective against strains of Klebsiella pneumoniae, Enterococcus faecalis and Escherichia coli (i.e. ZOI range: 1-2.8 mm). Similarly to the antibiotic-susceptible microorganisms, nine of ten antibiotic-resistant bacterial strains when grown on agar were more susceptible to the SCH dressing compared with the NCS. Although the microorganisms tested were universally less susceptible to the silver dressings when in their biofilm state, in the majority of cases, the SCH dressing demonstrated greater biofilm-inhibiting activity than the NCS.
含银等抗菌敷料目前被广泛用于控制伤口生物负荷，证明其疗效的测试主要涉及使用自由生活或浮游细菌的体外模型。在本研究中，使用标准琼脂试验对多种抗生素敏感和耐药细菌的准固着状态进行了测试，第二种方法使用泊洛沙姆凝胶（真实生物膜状态——泊洛沙姆促使微生物呈现更具临床相关性的生物膜表型）技术。使用抑菌圈（ZOI）试验评估了两种银敷料，即含银水凝胶（SCH）敷料和含纳米晶银敷料（NCS）对多种微生物的抗菌活性。当在琼脂上生长时（呈现每种生物体的准固着状态），与NCS相比，抗生素敏感微生物通常对SCH敷料更敏感。与SCH敷料相关的抑菌圈范围在5.7至17.5毫米之间；NCS对同一组生物体的抑菌圈范围在1.9至8.6毫米之间。当在泊洛沙姆凝胶上生长时（呈现每种生物体的生物膜状态），同一组微生物对两种敷料的敏感性均较低。SCH敷料对铜绿假单胞菌、白色念珠菌和金黄色葡萄球菌菌株最有效（抑菌圈范围：2.6 - 6毫米）；NCS对肺炎克雷伯菌、粪肠球菌和大肠杆菌菌株最有效（即抑菌圈范围：1 - 2.8毫米）。与抗生素敏感微生物类似，在琼脂上生长的十株抗生素耐药细菌菌株中有九株与NCS相比对SCH敷料更敏感。尽管所测试的微生物在生物膜状态下普遍对银敷料的敏感性较低，但在大多数情况下，SCH敷料显示出比NCS更强的生物膜抑制活性。
