Rennie M Y, Lindvere-Teene L, Tapang K, Linden R
MolecuLight, Inc., Toronto, ON, Canada.
Judy Dan Research and Treatment Centre, Ontario Wound Care Inc., North York, ON, Canada.
J Wound Care. 2017 Aug 2;26(8):452-460. doi: 10.12968/jowc.2017.26.8.452.
Bacteria in chronic wounds are invisible to the naked eye and can lead to delayed wound healing. Point-of-care bacterial fluorescence imaging illuminates a wound with 405nm light, triggering bacteria to produce red fluorescence and enabling real-time bacterial localisation. Prospective, single-blind clinical trials (clinicaltrials.gov #NCT02682069, #NCT03091361) were conducted to determine the positive predictive value (PPV) of this red fluorescence for detecting bacteria in chronic wounds.
Lower limb chronic wounds were imaged for bacterial fluorescence using the MolecuLight i:X imaging device. Regions positive for red fluorescence were discretely sampled using either biopsy or curettage to correlate red fluorescence signals to bacterial presence and analysed via gold standard quantitative polymerase chain reaction (qPCR) or via semi-quantitative culture analysis respectively.
A total of 60 lower limb chronic wounds were imaged. Quantitative PCR analysis of wound tissue biopsies obtained from regions of red fluorescence yielded a PPV of 100%. Total bacterial load in these areas was ≥10 CFU/g. Semi-quantitative culture analysis of curettage scrapings from regions of red fluorescence yielded a PPV of 100%, with predominately moderate or heavy bacterial growth. There were nine distinct bacterial species detected, all common pathogens in chronic wounds. Staphylococcus aureus was the most prevalent species.
Bacterial fluorescence image-guided curettage or biopsy sampling positively predicts bacterial presence in wounds at potentially harmful levels, entirely eliminating the risk of false negative sampling. Fluorescence imaging of wounds offers clinicians real-time information on a wound's bacterial burden, insight which can influence treatment decisions at the point-of care.
慢性伤口中的细菌肉眼不可见，可导致伤口愈合延迟。即时护理细菌荧光成像用405nm光照射伤口，促使细菌产生红色荧光，实现细菌的实时定位。开展了前瞻性单盲临床试验（clinicaltrials.gov #NCT02682069，#NCT03091361），以确定这种红色荧光检测慢性伤口中细菌的阳性预测值（PPV）。
使用MolecuLight i:X成像设备对下肢慢性伤口进行细菌荧光成像。对红色荧光阳性区域分别采用活检或刮除术进行离散采样，将红色荧光信号与细菌存在情况相关联，并分别通过金标准定量聚合酶链反应（qPCR）或半定量培养分析进行分析。
共对60个下肢慢性伤口进行了成像。对从红色荧光区域获取的伤口组织活检进行定量PCR分析，PPV为100%。这些区域的总细菌载量≥10 CFU/g。对红色荧光区域的刮除物进行半定量培养分析，PPV为100%，主要为中度或重度细菌生长。共检测到9种不同的细菌种类，均为慢性伤口中的常见病原体。金黄色葡萄球菌是最常见的种类。
细菌荧光图像引导下的刮除术或活检采样能准确预测伤口中存在潜在有害水平的细菌，完全消除假阴性采样的风险。伤口荧光成像为临床医生提供了关于伤口细菌负荷的实时信息，这一信息可影响即时护理时的治疗决策。
