Slone Will, Linton Sara, Okel Tyler, Corum Linda, Thomas John G, Percival Steven L
West Virginia University, Medical School, Department of Pathology, Biofilm Laboratory, Morgantown, WV, USA.
West Virginia University, Medical School, Department of Pathology, Biofilm Laboratory, Morgantown, WV, USA ; Advanced Medical Solutions, Winsford, Cheshire, UK.
J Am Col Certif Wound Spec. 2011 Jan 31;2(4):86-90. doi: 10.1016/j.jcws.2011.01.001. eCollection 2010 Dec.
Nonhealing and stalled chronic wounds are often reported to reside within an alkaline environment. Consequently, a number of researchers have proposed that lowering the pH of a chronic wound environment will enable healing to progress. However, it is not known whether the efficacies of silver-impregnated wound dressings are affected by pH.
To investigate whether pH has an effect on the antimicrobial barrier efficacy of a silver alginate wound dressing on wound isolates.
Twenty-five bacteria and yeasts that had been routinely isolated from chronic wounds were separately exposed to a silver alginate wound dressing with the use of a standardized corrected zone of inhibition (CZOI) assay.
The silver alginate dressing demonstrated a broad spectrum of antimicrobial barrier activity within the dressing against all wound isolates. However, at a pH of 5.5, compared with a pH of 7, the antimicrobial barrier activity of the silver alginate dressing significantly increased. For all yeasts the CZOI ranged from 6.25 to 11 mm at a pH of 7. At a pH of 5.5, the CZOI range increased from 8.5 to 12.25 mm. For the Gram-negative isolates, the CZOI ranged from 0.75 to 6.5 mm at a pH 7, compared with a CZOI range of 2.75 to 8 mm at pH 5.5. The CZOI for the Gram-positive isolates, including meticillin-resistant Staphylococcus aureus, ranged from 3 to 7.75 mm at pH 7 and from 4.5 to 11.75 mm at pH 5.5.
For all isolates tested, excluding one strain of Candida albicans and one vancomycin-resistant Enterococcus strain, lowering pH to 5.5 resulted in an improvement in the antimicrobial barrier activity within the silver alginate dressing. Based on these initial in vitro findings, it is possible to suggest that there may be benefits to maintaining an infected or recalcitrant wound in a slightly acid (pH 5.5) environment. In particular, doing so may lead to an enhanced antimicrobial barrier effect of silver, a quicker reduction in the wound microbial bioburden, and therefore a reduction in the need for prolonged antimicrobial use. However, more in vitro and in vivo studies would be warranted to further substantiate these claims.
据报道，难愈和停滞的慢性伤口通常处于碱性环境中。因此，许多研究人员提出，降低慢性伤口环境的pH值将促进伤口愈合。然而，尚不清楚含银伤口敷料的功效是否受pH值影响。
研究pH值是否对藻酸盐银伤口敷料对伤口分离菌的抗菌屏障功效有影响。
使用标准化校正抑菌圈（CZOI）试验，将25种从慢性伤口中常规分离出的细菌和酵母菌分别暴露于藻酸盐银伤口敷料。
藻酸盐银敷料对所有伤口分离菌在敷料内均表现出广泛的抗菌屏障活性。然而，与pH值为7相比，在pH值为5.5时，藻酸盐银敷料的抗菌屏障活性显著增加。对于所有酵母菌，在pH值为7时，CZOI范围为6.25至11毫米。在pH值为5.5时，CZOI范围从8.5增加到12.25毫米。对于革兰氏阴性分离菌，在pH值为7时，CZOI范围为0.75至6.5毫米，而在pH值为5.5时，CZOI范围为2.75至8毫米。包括耐甲氧西林金黄色葡萄球菌在内的革兰氏阳性分离菌的CZOI在pH值为7时为3至7.75毫米，在pH值为5.5时为4.5至11.75毫米。
对于所有测试的分离菌，除了一株白色念珠菌和一株耐万古霉素肠球菌菌株外，将pH值降至5.5可提高藻酸盐银敷料内的抗菌屏障活性。基于这些初步的体外研究结果，有可能表明将感染或顽固伤口维持在微酸性（pH值5.5）环境中可能有益。特别是，这样做可能会增强银的抗菌屏障作用，更快地降低伤口微生物生物负荷，并因此减少长期使用抗菌药物的必要性。然而，需要更多的体外和体内研究来进一步证实这些说法。
