Evaluation of the bacterial diversity among and within individual venous leg ulcers using bacterial tag-encoded FLX and Titanium amplicon pyrosequencing and metagenomic approaches

Randall D Wolcott,Yan Sun,Viktoria Gontcharova,Scot E Dowd

doi:10.1186/1471-2180-9-226

Randall D Wolcott, Yan Sun + Show 2 more

Open Access

https://doi.org/10.1186/1471-2180-9-226

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Abstract

BackgroundApproximately 1 out of every 100 individuals has some form of venous insufficiency, which can lead to chronic venous disease and Venous Leg Ulcer (VLU). There are known underlying pathologies which contribute to the chronic nature of VLU including biofilm phenotype infections.ResultsUsing pyrosequencing based approaches we evaluated VLU to characterize their microbial ecology. Results show that VLU infections are polymicrobial with no single bacterium colonizing the wounds. The most ubiquitous and predominant organisms include a previously uncharacterized bacteroidales, various anaerobes, Staphylococcus, Corynebacterium, and Serratia. Topological analysis of VLU show some notable differences in bacterial populations across the surface of the wounds highlighting the importance of sampling techniques during diagnostics. Metagenomics provide a preliminary indication that there may be protozoa, fungi and possibly an undescribed virus associated with these wounds.ConclusionThe polymicrobial nature of VLU and previous research on diabetic foot ulcers and surgical site infections suggest that the future of therapy for such wounds lies in the core of the logical and proven multiple concurrent strategy approach, which has been termed "biofilm-based wound care" and the use of individualized therapeutics rather than in a single treatment modality.

Highlights

1 out of every 100 individuals has some form of venous insufficiency, which can lead to chronic venous disease and Venous Leg Ulcer (VLU)
It is generally agreed that chronic venous disease (CVD) is caused by persistent venous hypertension in the lower extremities stemming from a decay in the efficiency and performance of oneway valves in perforating, superficial or deep veins
A total of 59,571 individual sequence reads longer than 200 bp were evaluated among the 40 samples with 46,993 sequences generating BLASTn hits against the bacterial database

Summary

Introduction

1 out of every 100 individuals has some form of venous insufficiency, which can lead to chronic venous disease and Venous Leg Ulcer (VLU). There are known underlying pathologies which contribute to the chronic nature of VLU including biofilm phenotype infections. 600,000 Americans suffer from venous leg ulcers (VLU), which are extremely costly to manage and produce significant suffering [1]. Hippocrates believed that VLU were the bodies way to vent "evil humors" and advocated such ulcers should not be treated. His philosophy was that such ulcers should be allowed to express these evil humors naturally [2,3]. It is generally agreed that chronic venous disease (CVD) is caused by persistent venous hypertension in the lower extremities stemming from a decay in the efficiency and performance of oneway valves in perforating, superficial or deep veins

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