The macrofilaricidal efficacy of repeated doses of ivermectin for the treatment of river blindness

Background: Mass drug administration (MDA) with ivermectin is the cornerstone of efforts to eliminate human onchocerciasis by 2020 or 2025. The feasibility of elimination crucially depends on the effects of multiple ivermectin doses on Onchocerca volvulus. A single ivermectin (standard) dose clears the skin-dwelling microfilarial progeny of adult worms (macrofilariae) and temporarily impedes the release of such progeny by female macrofilariae, but a macrofilaricidal effect has been deemed minimal. Multiple doses of ivermectin may cumulatively and permanently reduce the fertility and shorten the lifespan of adult females. However, rigorous quantification of these effects necessitates interrogating longitudinal data on macrofilariae with suitably powerful analytical techniques. Methods: Using a novel mathematical modeling approach, we analyzed, at an individual participant level, longitudinal data on viability and fertility of female worms from the single most comprehensive multiple-dose clinical trial of ivermectin, comparing 3-monthly with annual treatments administered for 3 years in Cameroon

Virtual special section `new challenges in antifungal therapy'

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MALDI-TOF-Based Dermatophyte Identification

International audienceMALDI-TOF MS has become increasingly popular for microorganism identification in the routine laboratory. Compared with conventional morphology- based techniques, MALDI-TOF is relatively inexpensive (per-unit identification), involves a rapid result turnaround time and yields more accurate results without the need for highly qualified staff. However, this technology has been technically difficult to implement for filamentous fungi identification. Identification of dermatophytes, a type of filamentous fungi, remains particularly challenging, partly due to the lack of clear species definition for some taxa or within some species complexes. Review of the ten studies published between 2008 and 2015 shows that the accuracy of MALDI-TOF MS-based identification varied between 13.5 and 100 % for dermatophytes. This variability was partly due to inconsistencies concerning critical steps of the routine clinical laboratory process. Use of both a complete formic acid-acetonitrile protein extraction step and a manufacturer library supplemented with homemade reference spectra is essential for an accurate species identification. This technique is conversely unaffected by variations in other routine clinical laboratory conditions such as culture medium type, incubation time and type of mass spectrometry instrument. Provided that a reference spectra library is adequate for dermatophyte identification, MALDI-TOF MS identification is more economical and offers an accuracy comparable to that of DNA sequencing. The technique also represents an advantageous alternative to the protracted and laborintensive dermatophyte identification via macroscopic and microscopic morphology in the routine clinical laboratory

Oral fungal-bacterial biofilm models in vitro: a review

International audienceInclusion of fungi as commensals in oral biofilm is an important innovation in oral biology, and this work aimed to review the literature on the available biofilm and related disease in vitro models. Actually, thousands of bacterial and around one hundred of fungal phylotypes can colonize the oral cavity. Taxonomic profiling combined with functional expression analysis has revealed that Candida albicans, Streptococcus mutans and prominent periodontopathogens are not always present or numerically important in candidiasis, caries, or periodontitis lesions. However, C. albicans combined with Streptococcus spp. co-increase their virulence in invasive candidiasis, early childhood caries or peri-implantitis. As Candida species and many other fungi are also members of oral microcosms in healthy individuals, mixed fungal-bacterial biofilm models are increasingly valuable investigative tools, and new fungal-bacterial species combinations need to be investigated. Here we review the key points and current methods for culturing in vitro mixed fungal-bacterial models of oral biofilms. According to ecosystem under study (health, candidiasis, caries, periodontitis), protocol design will select microbial strains, biofilm support (polystyrene plate, cell culture, denture, tooth, implant), pretreatment support (human or artificial saliva) and culture conditions. Growing mixed fungal-bacterial biofilm models in vitro is a difficult challenge. But reproducible models are needed, because oral hygiene products, food and beverage, medication, licit and illicit drugs can influence oral ecosystems. So, even though most oral fungi and bacteria are not cultivable, in vitro microbiological models should still be instrumental in adapting oral care products, dietary products and care protocols to patients at higher risk of oral diseases. Microbial biofilm models combined with oral epithelial cell cultures could also aid in understanding the inflammatory reaction

Building a center of excellence in biomedical research in an unfavorable environment: the Malaria Research and Training Center in Mali

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Eukaryotic and Prokaryotic Microbiota Interactions

The nature of the relationship between the communities of microorganisms making up the microbiota in and on a host body has been increasingly explored in recent years. Microorganisms, including bacteria, archaea, viruses, parasites and fungi, have often long co-evolved with their hosts. In human, the structure and diversity of microbiota vary according to the host's immunity, diet, environment, age, physiological and metabolic status, medical practices (e.g., antibiotic treatment), climate, season and host genetics. The recent advent of next generation sequencing (NGS) technologies enhanced observational capacities and allowed for a better understanding of the relationship between distinct microorganisms within microbiota. The interaction between the host and their microbiota has become a field of research into microorganisms with therapeutic and preventive interest for public health applications. This review aims at assessing the current knowledge on interactions between prokaryotic and eukaryotic communities. After a brief description of the metagenomic methods used in the studies were analysed, we summarise the findings of available publications describing the interaction between the bacterial communities and protozoa, helminths and fungi, either in vitro, in experimental models, or in humans. Overall, we observed the existence of a beneficial effect in situations where some microorganisms can improve the health status of the host, while the presence of other microorganisms has been associated with pathologies, resulting in an adverse effect on human health

Epidemiology of human dermatophytoses in Africa

International audienceIn this critical literature review, we summarize the epidemiological trends of dermatophytoses reported in Africa. Our findings clearly emphasize the heavy burden of dermatophytosis in Africa. Tinea capitis is the primary clinical presentation of dermatophytosis in African children throughout the entire African continent. The disease affects more than 20% of school-age children in West Africa, while the prevalence ranges from 10% to more than 70% in other regions of Africa. In African adults, the presence of tinea corporis is the most frequent indicator of dermatophytosis. However, epidemiological studies have been primarily conducted on particular patient groups that are not representative of the general population. We examined dermatophyte species distribution patterns. We observed a predominance of anthropophilic dermatophytes, mainly T. violaceum, in the North and East of Africa and both T. soudanense and M. audouinii in the Western and Central regions of the continent. Interestingly, the zoophilic species, M. canis, has recently emerged in North and East Africa. Optimization of both mycology diagnosis capacities and epidemiological methodology would provide insight into the role that climate and other global aspects of the human environment play in dermatophyte epidemiology. We advocate that using a multisectoral and collaborative strategy would strengthen such future studies

Comparison of Three Skin Sampling Methods and Two Media for Culturing Malassezia Yeast

International audienceMalassezia is a lipid-dependent commensal yeast of the human skin. The different culture media and skin sampling methods used to grow these fastidious yeasts are a source of heterogeneity in culture-based epidemiological study results. This study aimed to compare the performances of three methods of skin sampling, and two culture media for the detection of Malassezia yeasts by culture from the human skin. Three skin sampling methods, namely sterile gauze, dry swab, and TranswabTM with transport medium, were applied on 10 healthy volunteers at 5 distinct body sites. Each sample was further inoculated onto either the novel FastFung medium or the reference Dixon agar for the detection of Malassezia spp. by culture. At least one colony of Malassezia spp. grew on 93/300 (31%) of the cultures, corresponding to 150 samplings. The positive culture rate was 67%, 18%, and 15% (P < 10−3), for samples collected with sterile gauze, TranswabTM, and dry swab, respectively. The positive culture rate was 62% and 38% (P < 0.003) by using the FastFung and the Dixon media, respectively. Our results showed that sterile gauze rubbing skin sampling followed by inoculation on FastFung medium should be implemented in the routine clinical laboratory procedure for Malassezia spp. cultivation

“Chiclero’s Ulcer” Due to Leishmania mexicana in Travelers Returning from Central America: A Case Report and Review of the Literature

International audienceCutaneous leishmaniasis (CL) due to a New World species of Leishmania is increasingly seen among returning international travelers, and most cases arise from travel to Mexico, Central and South America. We described a case of CL in a women presenting a nonhealing ulceration under her right ear with slight increase of size of the left parotid gland under the skin lesion, evolving for 4 months. In her history of travel, she reported a ten-day stay in Mexico during the Christmas vacation in the Yucatan region with only half a day walking in the tropical forest. Diagnosis of CL due to Leishmania mexicana was done via PCR detection and sequencing from swab sampling of the lesion. The patient recovered without antiparasitic treatment. Clinicians should consider diagnosing Chiclero’s ulcer in patients returning from endemic areas such as Central America and Texas who present with chronic ulceration. A noninvasive sampling is sufficient for the PCR-based diagnosis of this disease