Pati Brooke A, Kurata Wendy E, Horseman Timothy S, Pierce Lisa M
Department of General Surgery, Tripler Army Medical Center, Honolulu, Hawaii, USA.
Department of Clinical Investigation, Tripler Army Medical Center, Honolulu, Hawaii, USA.
Wound Repair Regen. 2021 Mar;29(2):316-326. doi: 10.1111/wrr.12890. Epub 2021 Jan 22.
As antibiotic resistance continues to increase globally, there is an urgency for novel, non-antibiotic approaches to control chronic drug-resistant infections, particularly those associated with polymicrobial biofilm formation in chronic wounds. Also needed are clinically relevant polymicrobial biofilm models that can be utilized to assess the efficacy of innovative therapeutics against mature biofilms. We successfully developed a highly reproducible porcine ex vivo skin wound polymicrobial biofilm model using clinical isolates of multidrug-resistant Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Candida albicans. This ex vivo biofilm model was then used to assess the antimicrobial and antibiofilm properties of an easily fabricated chitosan hydrogel incorporating the natural antimicrobial peptide epsilon-poly-L-lysine. Antimicrobial activity was evaluated against planktonic cultures in vitro and against mature biofilms ex vivo. The antibiofilm efficiency of the hydrogels was especially pronounced against Pseudomonas aeruginosa, whose counts were reduced by 99.98% after 2 hours in vitro and by 99.94% after treatment for 24 hours when applied to 24 hour ex vivo polymicrobial wound biofilms. The activity of the hydrogels was lower against Staphylococcus aureus and ineffective against Candida albicans. Gram, Hucker-Twort staining of paraffin sections revealed balanced polymicrobial communities in mature 48 hour untreated biofilms. Treatment of 48 or 72 hour biofilms for 2 or 3 days with hydrogels that were applied within 5 hours after inoculation resulted in an impressive 96% and 97% reduction in biofilm thickness compared to untreated biofilms, respectively (P < .001). Likewise, topical gel treatment for 24 hours reduced biofilm thickness by 84% and 70%, respectively, when applied to mature biofilms at 24 and 48 hours after inoculation (P < .001). Thus, this ex vivo wound biofilm model provides a useful means to assess the efficacy of novel treatments to prevent and eradicate polymicrobial biofilms consisting of multidrug-resistant Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Candida albicans.
随着全球抗生素耐药性持续增加，迫切需要新的非抗生素方法来控制慢性耐药感染，尤其是与慢性伤口中多微生物生物膜形成相关的感染。还需要具有临床相关性的多微生物生物膜模型，可用于评估创新疗法对成熟生物膜的疗效。我们使用多重耐药铜绿假单胞菌、耐甲氧西林金黄色葡萄球菌和白色念珠菌的临床分离株，成功开发了一种高度可重复的猪离体皮肤伤口多微生物生物膜模型。然后，该离体生物膜模型用于评估一种易于制备的壳聚糖水凝胶的抗菌和抗生物膜特性，该水凝胶含有天然抗菌肽ε-聚-L-赖氨酸。评估了其对体外浮游培养物和离体成熟生物膜的抗菌活性。水凝胶的抗生物膜效率对铜绿假单胞菌尤为显著，当应用于24小时的离体多微生物伤口生物膜时，其数量在体外2小时后减少了99.98%，处理24小时后减少了99.94%。水凝胶对金黄色葡萄球菌的活性较低，对白色念珠菌无效。石蜡切片的革兰氏、胡克-特沃特染色显示，在未处理的48小时成熟生物膜中存在平衡的多微生物群落。在接种后5小时内应用水凝胶对48或72小时生物膜进行2或3天的处理，与未处理的生物膜相比，生物膜厚度分别显著降低了96%和97%（P < .001）。同样，当在接种后24小时和48小时应用于成熟生物膜时，局部凝胶处理24小时分别使生物膜厚度降低了84%和70%（P < .001）。因此，这种离体伤口生物膜模型为评估新型治疗方法预防和根除由多重耐药铜绿假单胞菌、耐甲氧西林金黄色葡萄球菌和白色念珠菌组成的多微生物生物膜的疗效提供了一种有用的手段。
