Molecular detection of Mycobacterium ulcerans in the environment and its relationship with Buruli ulcer occurrence in Zio and Yoto districts of maritime region in Togo.

Issaka Maman,Edith Nyaku,Ekanao Tedihou,Franz Xaver Wiedemann,Kossi Badziklou,Komi Amekuse,Abiba Banla Kere,Tchadjobo Tchacondo,Gisela Bretzel,Marcus Beissner,Damintoti Simplice Karou

doi:10.1371/journal.pntd.0006455

Abstract

BackgroundBuruli Ulcer (BU) is a neglected tropical skin infection caused by Mycobacterium ulcerans. Residence near aquatic areas has been identified as an important source of transmission of M. ulcerans with increased risk of contracting Buruli ulcer. However, the reservoir and the mode of transmission are not yet well known. The aim of this study was to identify the presence of M. ulcerans in the environment and its relationship with Buruli ulcer occurrence in Zio and Yoto districts of the maritime region in south Togo.MethodsA total of 219 environmental samples including soil (n = 119), water (n = 65), biofilms/plants (n = 29) and animals’ feces (n = 6) were collected in 17 villages of Zio and Yoto districts of the maritime region in Togo. DNA of M. ulcerans including IS2404 and IS2606 insertions sequences and mycolactone ketoreductase-B gene (KR-B) was detected using real time PCR amplification (qPCR) technique. In parallel, clinical samples of patients were tested to establish a comparison of the genetic profile of M. ulcerans between the two types of samples. A calibration curve was generated for IS2404 from a synthetic gene of M. ulcerans Transposase pMUM001, the plasmid of virulence.ResultsIn the absence of inhibition of the qPCR, 6/219 (2.7%) samples were tested positive for M. ulcerans DNA containing three sequences (IS2404/IS2606/KR-B). Positive samples of M. ulcerans were consisting of biofilms/plants (3/29; 10.3%), water (1/65; 1.7%) and soil (2/119; 1.5%). Comparative analysis between DNA detected in environmental and clinical samples from BU patients showed the same genetic profile of M. ulcerans in the same environment. All these samples were collected in the environment of Haho and Zio rivers in the maritime region.ConclusionThis study confirms the presence of M. ulcerans in the environment of the Zio and Yoto districts of the maritime region of Togo. This may explain partially, the high rates of Buruli ulcer patients in this region. Also, water, plants and soil along the rivers could be possible reservoirs of the bacterium. Therefore, Haho and Zio rivers could be potential sources of infection with M. ulcerans in humans in these districts.

Highlights

Buruli ulcer (BU) is an infectious skin disease caused by the Mycobacterium ulcerans [1,2,3]
In the absence of inhibition of the qPCR, 6/219 (2.7%) samples were tested positive for M. ulcerans DNA containing three sequences (IS2404/IS2606/ketoreductase-B gene (KR-B))
Mycobacterium ulcerans presence in the environment and Buruli ulcer occurrence in Togo

Summary

Introduction

Buruli ulcer (BU) is an infectious skin disease caused by the Mycobacterium ulcerans [1,2,3]. The rate of mortality of Buruli ulcer is low, the serious morbidity caused by the disease includes functional disabilities that may result in permanent social, economic and developmental problems. Mycolactone is the product of three major complex enzymes called polyketide synthases which are coded by mlsA1 (51Kb), mlsA2 (7 Kb) and mlsB (42 Kb) genes. These genes are located on the plasmid of virulence of the mycobacterium known as pMUM001[5,6]. Buruli Ulcer (BU) is a neglected tropical skin infection caused by Mycobacterium ulcerans. The aim of this study was to identify the presence of M. ulcerans in the environment and its relationship with Buruli ulcer occurrence in Zio and Yoto districts of the maritime region in south Togo

Objectives

Methods

Results

Conclusion