Mycobacterium ulcerans persistence at a village water source of Buruli ulcer patients

PLoS Negl Trop Dis. 2014 Mar 27;8(3):e2756. doi: 10.1371/journal.pntd.0002756. eCollection 2014 Mar.

Abstract

Buruli ulcer (BU), a neglected tropical disease of the skin and subcutaneous tissue, is caused by Mycobacterium ulcerans and is the third most common mycobacterial disease after tuberculosis and leprosy. While there is a strong association of the occurrence of the disease with stagnant or slow flowing water bodies, the exact mode of transmission of BU is not clear. M. ulcerans has emerged from the environmental fish pathogen M. marinum by acquisition of a virulence plasmid encoding the enzymes required for the production of the cytotoxic macrolide toxin mycolactone, which is a key factor in the pathogenesis of BU. Comparative genomic studies have further shown extensive pseudogene formation and downsizing of the M. ulcerans genome, indicative for an adaptation to a more stable ecological niche. This has raised the question whether this pathogen is still present in water-associated environmental reservoirs. Here we show persistence of M. ulcerans specific DNA sequences over a period of more than two years at a water contact location of BU patients in an endemic village of Cameroon. At defined positions in a shallow water hole used by the villagers for washing and bathing, detritus remained consistently positive for M. ulcerans DNA. The observed mean real-time PCR Ct difference of 1.45 between the insertion sequences IS2606 and IS2404 indicated that lineage 3 M. ulcerans, which cause human disease, persisted in this environment after successful treatment of all local patients. Underwater decaying organic matter may therefore represent a reservoir of M. ulcerans for direct infection of skin lesions or vector-associated transmission.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Buruli Ulcer / epidemiology*
  • Cameroon
  • Child
  • Child, Preschool
  • Cluster Analysis
  • DNA Transposable Elements
  • DNA, Bacterial / genetics
  • DNA, Bacterial / isolation & purification*
  • Endemic Diseases*
  • Female
  • Genotype
  • Humans
  • Male
  • Middle Aged
  • Molecular Epidemiology
  • Mycobacterium ulcerans / classification
  • Mycobacterium ulcerans / genetics
  • Mycobacterium ulcerans / isolation & purification*
  • Real-Time Polymerase Chain Reaction
  • Rural Population
  • Water Microbiology*

Substances

  • DNA Transposable Elements
  • DNA, Bacterial

Grant support

The Medicor Foundation, as the funder of this study, had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.