Challenges to effective control of tuberculosis and drug resistance in African countries

Drug-resistant tuberculosis (TB) appeared soon after the introduction of chemotherapy and is considered a man-made phenomenon. Despite the efficacy of short course chemotherapy, which includes a cocktail of drugs and has been generally recommended since the 1960s, increasing numbers of multi-drug-resistant (MDR) cases were reported worldwide in the early 1990s. In the WHO’s 2004 report on surveillance of drug-resistant TB, MDRTB is   reported from over 100 countries. Although little data is available on drug-resistant TB in Africa, this paper presents an overview of the current situation on the African continent, which is severely affected by the TB epidemic

Evolution of two distinct phylogenetic lineages of the emerging human pathogen Mycobacterium ulcerans

<p>Abstract</p> <p>Background</p> <p>Comparative genomics has greatly improved our understanding of the evolution of pathogenic mycobacteria such as <it>Mycobacterium tuberculosis</it>. Here we have used data from a genome microarray analysis to explore insertion-deletion (InDel) polymorphism among a diverse strain collection of <it>Mycobacterium ulcerans</it>, the causative agent of the devastating skin disease, Buruli ulcer. Detailed analysis of large sequence polymorphisms in twelve regions of difference (RDs), comprising irreversible genetic markers, enabled us to refine the phylogenetic succession within <it>M. ulcerans</it>, to define features of a hypothetical <it>M. ulcerans </it>most recent common ancestor and to confirm its origin from <it>Mycobacterium marinum</it>.</p> <p>Results</p> <p><it> M. ulcerans </it>has evolved into five InDel haplotypes that separate into two distinct lineages: (i) the "classical" lineage including the most pathogenic genotypes – those that come from Africa, Australia and South East Asia; and (ii) an "ancestral" <it>M. ulcerans </it>lineage comprising strains from Asia (China/Japan), South America and Mexico. The ancestral lineage is genetically closer to the progenitor <it>M. marinum </it>in both RD composition and DNA sequence identity, whereas the classical lineage has undergone major genomic rearrangements.</p> <p>Conclusion</p> <p>Results of the InDel analysis are in complete accord with recent multi-locus sequence analysis and indicate that <it>M. ulcerans </it>has passed through at least two major evolutionary bottlenecks since divergence from <it>M. marinum</it>. The classical lineage shows more pronounced reductive evolution than the ancestral lineage, suggesting that there may be differences in the ecology between the two lineages. These findings improve the understanding of the adaptive evolution and virulence of <it>M. ulcerans </it>and pathogenic mycobacteria in general and will facilitate the development of new tools for improved diagnostics and molecular epidemiology.</p

DNA fingerprinting analyses of M tuberculosis-complex isolates from the Free State, South Africa, as part of a multidisciplinary study

The objective of this study was to serve as a complement to socio-economic analyses of TB patients in a DOTS system, providing microbiological data and documenting the TB population dynamics. Sputum samples were collected from smear-positive TB patients in the Goldfields, Thaba Nchu and Qwaqwa areas. Laboratory analyses comprised the culturing of Mycobacterium tuberculosis isolates and DNA fingerprinting. The primary aim was hampered by problems encountered during specimen sampling, inadequate resources, and a low culture-positivity rate. Nevertheless, the fingerprinting data of a random sample showed a heterogenous TB population,   suggesting that reactivation might be an important factor in the area studied. Clustering was the highest in the mining area. Preliminary data from serial isolates also detected possible re-infection during treatment or initial mixed infections in five of the eleven patients

Buruli Ulcer (M. ulcerans Infection): New Insights, New Hope for Disease Control

Buruli ulcer is a disease of skin and soft tissue caused by Mycobacterium ulcerans. It can leave affected people scarred and disabled. What are the prospects for disease control

Rapid culture-based methods for drug-resistance detection in Mycobacterium tuberculosis.

Tuberculosis still represents a major public health problem, especially in low-resource countries where the burden of the disease is more important. Multidrug-resistant and extensively drug drug-resistant tuberculosis constitute serious problems for the efficient control of the disease stressing the need to investigate resistance to first- and second-line drugs. Conventional methods for detecting drug-resistance in Mycobacterium tuberculosis are slow and cumbersome. The most commonly used proportion method on Löwenstein-Jensen medium or Middlebrook agar requires a minimum of 3-4 weeks to produce results. Several new approaches have been proposed in the last years for the rapid and timely detection of drug-resistance in tuberculosis. This review will address phenotypic culture-based methods for rapid drug susceptibility testing in M. tuberculosis

Challenges to effective control of tuberculosis and drug resistance in African countries

Drug-resistant tuberculosis (TB) appeared soon after the introduction of chemotherapy and is considered a man-made phenomenon. Despite the efficacy of short course chemotherapy, which includes a cocktail of drugs and has been generally recommended since the 1960s, increasing numbers of multi-drug-resistant (MDR) cases were reported worldwide in the early 1990s. In the WHO’s 2004 report on surveillance of drug-resistant TB, MDRTB is&nbsp;&nbsp; reported from over 100 countries. Although little data is available on drug-resistant TB in Africa, this paper presents an overview of the current situation on the African continent, which is severely affected by the TB epidemic