Invagination intestinale aiguë consécutive à un lipome grèlique: à propos d’un cas et revue de la littérature

L’invagination intestinale aiguë est une pathologie du nourrisson et du petit enfant. Sa survenue chez l’adulte est très inhabituelle. Elle estd’étiologie diverse. Dans l’immense majorité des cas, elle est secondaire à une tumeur qui peut être bénigne ou maligne. L’invagination intestinalesur lipome est exceptionnelle. Nous rapportons un cas d’invagination intestinale grêlo-grêlique sur lipome.Key words: Invagination, grele, lipom

Single Nucleotide Polymorphism Typing of Mycobacterium ulcerans Reveals Focal Transmission of Buruli Ulcer in a Highly Endemic Region of Ghana

Buruli ulcer (BU) is an emerging necrotizing disease of the skin and subcutaneous tissue caused by Mycobacterium ulcerans. While proximity to stagnant or slow flowing water bodies is a risk factor for acquiring BU, the epidemiology and mode of M. ulcerans transmission is poorly understood. Here we have used high-throughput DNA sequencing and comparisons of the genomes of seven M. ulcerans isolates that appeared monomorphic by existing typing methods. We identified a limited number of single nucleotide polymorphisms (SNPs) and developed a real-time PCR SNP typing method based on these differences. We then investigated clinical isolates of M. ulcerans on which we had detailed information concerning patient location and time of diagnosis. Within the Densu river basin of Ghana we observed dominance of one clonal complex and local clustering of some of the variants belonging to this complex. These results reveal focal transmission and demonstrate, that micro-epidemiological analyses by SNP typing has great potential to help us understand how M. ulcerans is transmitted

Mycobacterium ulcerans disease: experience with primary oral medical therapy in an Australian cohort

Mycobacterium ulcerans (MU) is responsible for disfiguring skin infections which are challenging to treat. The recommended treatment for MU has continued to evolve from surgery to remove all involved tissue, to the use of effective combination oral antibiotics with surgery as required. Our study describes the oral medical treatment utilised for consecutive cases of MU infection over a 15 month period at our institution, in Victoria, Australia. Managing patients primarily with oral antibiotics results in high cure rates and excellent cosmetic outcomes. The success with medical treatment reported in this study will aid those treating cases of MU infection, and will add to the growing body of knowledge about the relative roles of antibiotics and surgery for treating this infection

Genomic Diversity and Evolution of Mycobacterium ulcerans Revealed by Next-Generation Sequencing

Mycobacterium ulcerans is the causative agent of Buruli ulcer, the third most common mycobacterial disease after tuberculosis and leprosy. It is an emerging infectious disease that afflicts mainly children and youths in West Africa. Little is known about the evolution and transmission mode of M. ulcerans, partially due to the lack of known genetic polymorphisms among isolates, limiting the application of genetic epidemiology. To systematically profile single nucleotide polymorphisms (SNPs), we sequenced the genomes of three M. ulcerans strains using 454 and Solexa technologies. Comparison with the reference genome of the Ghanaian classical lineage isolate Agy99 revealed 26,564 SNPs in a Japanese strain representing the ancestral lineage. Only 173 SNPs were found when comparing Agy99 with two other Ghanaian isolates, which belong to the two other types previously distinguished in Ghana by variable number tandem repeat typing. We further analyzed a collection of Ghanaian strains using the SNPs discovered. With 68 SNP loci, we were able to differentiate 54 strains into 13 distinct SNP haplotypes. The average SNP nucleotide diversity was low (average 0.06–0.09 across 68 SNP loci), and 96% of the SNP locus pairs were in complete linkage disequilibrium. We estimated that the divergence of the M. ulcerans Ghanaian clade from the Japanese strain occurred 394 to 529 thousand years ago. The Ghanaian subtypes diverged about 1000 to 3000 years ago, or even much more recently, because we found evidence that they evolved significantly faster than average. Our results offer significant insight into the evolution of M. ulcerans and provide a comprehensive report on genetic diversity within a highly clonal M. ulcerans population from a Buruli ulcer endemic region, which can facilitate further epidemiological studies of this pathogen through the development of high-resolution tools

Distribution of Mycobacterium ulcerans in Buruli Ulcer Endemic and Non-Endemic Aquatic Sites in Ghana

Mycobacterium ulcerans, the causative agent of Buruli ulcer, is an emerging environmental bacterium in Australia and West Africa. The primary risk factor associated with Buruli ulcer is proximity to slow moving water. Environmental constraints for disease are shown by the absence of infection in arid regions of infected countries. A particularly mysterious aspect of Buruli ulcer is the fact that endemic and non-endemic villages may be only a few kilometers apart within the same watershed. Recent studies suggest that aquatic invertebrate species may serve as reservoirs for M. ulcerans, although transmission pathways remain unknown. Systematic studies of the distribution of M. ulcerans in the environment using standard ecological methods have not been reported. Here we present results from the first study based on random sampling of endemic and non-endemic sites. In this study PCR-based methods, along with biofilm collections, have been used to map the presence of M. ulcerans within 26 aquatic sites in Ghana. Results suggest that M. ulcerans is present in both endemic and non-endemic sites and that variable number tandem repeat (VNTR) profiling can be used to follow chains of transmission from the environment to humans. Our results suggesting that the distribution of M. ulcerans is far broader than the distribution of human disease is characteristic of environmental pathogens. These findings imply that focal demography, along with patterns of human water contact, may play a major role in transmission of Buruli ulcer

Molecular diagnosis of nontuberculous mycobacteria

PURPOSE OF REVIEW: Diagnosis of infection due to nontuberculous mycobacteria is not easy, as it must be distinguished from colonization or contamination by other nontuberculous mycobacteria. Molecular methods offer many advantages over conventional methods of identification. The results are obtained rapidly, are reliable and reproducible, and even mixed or contaminated cultures can be examined. This review highlights the recent advances in molecular techniques for identification of nontuberculous mycobacteria. RECENT FINDINGS: Nontuberculous mycobacteria are ubiquitous towards the environment and have the potential to colonize and cause serious infection. An increasing number of species and clinical presentations are being described, and progress has been made towards the understanding of the underlying predisposing factors. Disease caused by nontuberculous mycobacteria is often associated with various forms of immunosuppression, particularly HIV infection, whereas mild forms of immune defects have been observed in some patients who, apart from their nontuberculous mycobacterial disease, seem to be healthy on initial examination. Molecular techniques have shown their usefulness for the identification of most mycobacteria. Probes are widely used in clinical laboratories for the identification of the most common mycobacterial species. Because automated DNA sequencing and the programs for analysing sequence data have become technically simpler, polymerase chain reaction-based sequencing is now used in many mycobacterial reference laboratories as a routine method for species identification. SUMMARY: Significant advances have been made with molecular tools for diagnosis of mycobacteria. The DNA microarray technique holds great promise for the future because it is easy to perform, it can be readily automated, and it allows the identification of a large number of mycobacterial species in one reaction

Evaluation of amplified fragment length polymorphism analysis for inter- and intraspecific differentiation of Mycobacterium bovis, M. tuberculosis, and M. ulcerans

The usefulness of amplified fragment length polymorphism (AFLP) analysis was evaluated for the discrimination of Mycobacterium bovis (17 strains), M. tuberculosis (15 strains), and M. ulcerans (12 strains) at the inter- and intraspecific level. The AFLP technique is a whole-genome coverage genotypic fingerprinting method based on the selective PCR amplification of modified restriction fragments obtained through a double enzymatic digest and subsequent ligation of double-stranded restriction site-specific adapter oligonucleotides. Selective amplification of ApaI/TaqI templates with primer combination A02-T02 (both having an additional C at their 3' end) generated autoradiographic AFLP fingerprints that were grouped by numerical analysis in two main AFLP clusters allowing clear separation of M. ulcerans (cluster I) from the M. tuberculosis complex members M. bovis and M. tuberculosis (cluster II). Calculation of similarities using the band-based Dice correlation coefficient instead of the Pearson product-moment correlation coefficient revealed a further subgrouping in cluster II. The two resulting subclusters corresponded with the phenotypic identity of M. bovis and M. tuberculosis, respectively, and could also be visually identified by two AFLP marker bands. Because of the relatively low degree of genotypic variation among the AFLP band patterns of the latter two taxa, no correlation could be found with previously reported molecular typing data or with geographical origin. The use of primer combination A02-T01 (the latter having an A as selective base) did not increase the resolving power within the M. tuberculosis complex but resulted in a visual subgrouping of the M. ulcerans strains that was not observed with primer combination A02-T02. Based on the presence or absence of a single AFLP marker band, the M. ulcerans isolates could be unambiguously classified in two continental types corresponding with the African and Australian origin of the strains, respectively. In conclusion, the radioactive AFLP method proved to be a reproducible and reliable taxonomic tool for the differentiation of the three mycobacterial species under study and also demonstrated its potential use for typing of M. ulcerans strains when employing multiple primer combinations

The use of IS2404 restriction fragment length polymorphisms suggests the diversity of Mycobacterium ulcerans from different geographical areas.

Abstract. Buruli ulcer, caused by Mycobacterium ulcerans, has been reported in five continents: Africa, Asia, Australia, and North and South America. In the present study, restriction fragment length polymorphism with the recently described M. ulcerans specific insertion sequence IS2404 as a probe, was applied to Mycobacterium shin-shuense, Mycobacterium marinum, and 14 clinical M. ulcerans isolates originating from six geographic areas: Africa (n 6), Australia (n 2), Mexico (n 1), south Asia (n 2), Asia (n 1), and South America (n 2). Using this probe, six subtypes of M. ulcerans, related to the six geographic origins of the isolates were distinguished, confirming that M. ulcerans can be divided into subgroups corresponding to different geographic variants of the same species