Molecular Characterization of Mycolactone Producing Mycobacteria from Aquatic Environments in Buruli Ulcer Non-Endemic Areas in Côte d’Ivoire

Abstract

Non-tuberculous mycobacteria (NTM), particularly mycolactone producing mycobacteria (MPM), are bacteria found in aquatic environments causing skin diseases in humans like Buruli ulcer (BU). Although the causative agent for BU, Mycobacterium ulcerans has been identified and associated with slow-moving water bodies, the real transmission route is still unknown. This study aimed to characterize MPMs from environmental aquatic samples collected in a BU non-endemic community, Adiopodoumé, in Côte d’Ivoire. Sixty samples were collected in four types of matrices (plant biofilms, water filtrate residues, plant detritus and soils) from three water bodies frequently used by the population. Using conventional polymerase chain reaction (PCR), MPMs were screened for the 16S ribosomal RNA (rRNA) mycobacterial gene, the IS2404 insertion sequence, and MPM enoyl reductase (ER) gene. Variable Number Tandem Repeat (VNTR) typing with loci 6, 19, mycobacterial interspersed repetitive unit 1 (MIRU1) and sequence type 1(ST1) was performed to discriminate between different MPMs. Our findings showed 66.7%, 57.5% and 43.5% of positivity respectively for 16S rRNA, IS2404 and ER. MPM discrimination using VNTR typing did not show any positivity and therefore did not allow precise MPM distinction. Nevertheless, the observed contamination of some water bodies in a BU non-endemic community by MPMs suggests the possibility of pathogen dissemination and transmission to humans. These aquatic environments could also serve as reservoirs that should be considered during control and prevention strategies.

Buruli Ulcer, a Prototype for Ecosystem-Related Infection, Caused by Mycobacterium ulcerans

“…Another study in Ghana detected M. ulcerans in biofilm, soil, filters, and detritus (63). Recently, using real-time PCR in samples to amplify the M. ulcerans IS2404 and KR-B genes, M. ulcerans was detected in stagnant water specimens, soil, water filtrate residues, and plants in Côte d'Ivoire, thereby confirming that water is a reservoir of M. ulcerans in areas of endemicity of Côte d'Ivoire (106,146). Bodies of water act as vehicles for disseminating M. ulcerans strains (Fig.…”

“…Salinity conditions occur in coastal, arid, and semiarid areas. In assuming that the salinity of the water and soil is a factor of M. ulcerans viability in the environment, we summarized soil and water salinity in Côte d'Ivoire as an example for West African countries, especially since M. ulcerans DNA was detected from a soil sample collected near rice paddy fields in Côte d'Ivoire (106,146). The average salinity of lagoons in Côte d'Ivoire ranges between 4 and 19 mg/liter, whereas the salinity of rivers at their outlet in the south varied between 0 g/liter and 30 g/liter (179)(180)(181)(182)(183)(184)(185).…”

“…In Ghana, M. ulcerans was detected in soil by searching for the KR-B gene only (13) and recently by the use of several PCR systems detecting heat shock protein 65, IS2404, IS2606, rpoB, and the ketoreductase gene (39). Plants, aquatic invertebrates, amphibians, and specific water conditions might allow M. ulcerans to grow and persist in the environment (16,37,40,40,121,146,158,192,193). Rice fields include all the risk factors for transmission of Buruli ulcer.…”

Ulcère de Buruli : Connaissance et Rôle des Plantes dans la Transmission de la Maladie dans Quatre Villages des Districts Sanitaires de Daloa et Bouaké (Côte d’Ivoire)

“…En effet, ces plantes pourraient porter des biofilms. Les études ont démontré que les biofilms de plantes expriment la présence de l'ADN de M. ulcerans (Tano et al, 2017).…”

From hidden outbreaks to epidemic emergencies: the threat associated with neglecting emerging pathogens

“…The virulent strain is known to cause painful skin lesions known as Buruli ulcers, named after the Ugandan region where this infection was first described [70]. The bacterium and associated disease has subsequently been found in several other areas of Africa including Angola [71], Benin [72], the Democratic Republic of the Congo [71], Côte D'Ivoire [73], Ghana [74], Nigeria [75], and Togo [76]. The infection also has been identified in Australia [77], and most recently Jordan [78].…”