First Detection of Ketoreductase in the Genome of Potentially Pathogenic Fast-Growing Environmental Mycobacteria Isolated in Ivory Coast

Mycobacterium ulcerans (MU), the causative agent of Buruli ulcer (BU), skin disease, is considered to
be an environmental pathogen. The pathogenic virulence of MU is being linked to the expression of
toxin called Mycolactone. The ketoreductase (KR) gene, is one of the synthesis genes of mycolactone
enzymes previously found in M. ulcerans. Genetic analyses using variable number tandem repeats
(VNTR) and mycobacterial interspersed repetitive units (MIRU) have shown high diversity in M.
ulcerans and in mycolactone producing Mycobacteria (MPMs).
Aim: The purpose of this study is to detect ketoreductase gene in the genome of environmental
mycobacteria strain, apart the M. ulcerans, from aquatic environments in Côte d’Ivoire.
Place and Duration of the Study: The analysis of the samples took place in the laboratories of
Institut Pasteur de Côte d’Ivoire in Abidjan City between June 2014 and December 2015. Sampling
was done in some hypoendemic and hyperendemic sites of Buruli Ulcer of Côte d’Ivoire.
Methodology: A total of 473 samples were collected comprising of 251 waters and 222 sediments
based on sampling sites. PCR diagnostics using IS2404 and KR were performed on strains.
Results: 20% fast growing isolated mycobacteria species including Mycobacterium mucogenicum,
Mycobacterium peregrinum and Mycobacterium sp. was found carrying the IS2404 gene previously
found in M. ulcerans. 9.23% of strains carried the ketoreductase (KR) genes, one of the synthesis of
mycolactone enzyme.
Conclusion: The results of this study proved the existence of ketoreductase (KR) genes in rapidlygrowing
mycobacteria. This study is one of the steps taken in order to understand different skin
infections encountered in Côte d’Ivoire. Cutaneous ulceration is a public health problem in Côte
d'Ivoire. This work showed a probable involvement of non ulcerans mycobacteria in the spread of this
disease. Investigations must therefore continue in order to confirm this observation in clinical practice.
All of which could help to determine the likely prevalence of skin ulcers due to Mycobacterium other
than M. ulcerans to better adapt treatment in Côte d'Ivoire.This study will help to better diagnose
patients suffering from skin infections other than Buruli ulcer and to consider strategies and means of
protection of the population against all mycobacterioses by breaking the epidemiological chain.