Center Dinfectiologie Christophe Merieux Du Laos

Vientiane, Laos

Center Dinfectiologie Christophe Merieux Du Laos

Vientiane, Laos
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Cosson J.F.,French National Institute for Agricultural Research | Galan M.,French National Institute for Agricultural Research | Bard E.,French National Institute for Agricultural Research | Razzauti M.,French National Institute for Agricultural Research | And 9 more authors.
Parasites and Vectors | Year: 2015

Orientia bacterium is the agent of the scrub typhus, a seriously neglected life-threatening disease in Asia. Here, we report the detection of DNA of Orientia in rodents from Europe and Africa. These findings have important implications for public health. Surveillance outside Asia, where the disease is not expected by sanitary services, needs to be improved. © 2015 Cosson et al.; licensee BioMed Central.

Wells K.,University of Adelaide | O'Hara R.B.,Biodiversity and Climate Research Center | Morand S.,Center dInfectiologie Christophe Merieux du Laos | Lessard J.-P.,McGill University | And 2 more authors.
Diversity and Distributions | Year: 2015

Aim: Geographic spread and range expansion of species into novel environments may merge originally separated species assemblages, yet the possible drivers of geographic heterogeneity in host-parasite associations remain poorly understood. Here, we examine global patterns in the parasite assemblages of two rat species and explore the role of parasite acquisition from local pools of host species. Location: Global. Methods: We compiled a global data set of helminth parasites (n = 241 species) from two rat species (Rattus rattus species complex, R. norvegicus) and, concomitantly, from all other mammal species known to be infected by the same parasites. We used an inverse Bayesian modelling approach to explicitly link species-level to community-level infestation probabilities at different geographic scales and alleviate the shortcoming of sampling bias. Results: Patterns of species richness and turnover of parasites in the two focal rat species revealed clear biogeographic structure with lowest species richness and most distinct assemblages in Madagascar and highest species richness and least distinct assemblages in the Palaearctic region. Parasite species richness and turnover across regions were correlated for the two focal hosts, although they were associated with distinct assemblages within regions. Infection probability of a focal host with any given parasite was clearly related to infection probability of the local species pool of wildlife hosts with that same parasite. Infection probability of other mammal species infected with these parasite species, in turn, decreased with their taxonomic distance to the genus Rattus. Main conclusions: Our study demonstrates the importance of spillover of parasites from local wildlife hosts to invasive rats on global patterns of host-parasite associations. Considering both changes in local pools of host species and the global distributions of parasite and pathogen diversity in consistent model frameworks may therefore advance the forecasting of species-level infestation patterns and the possible risk of disease emergence from local to global scale. © 2014 John Wiley & Sons Ltd.

Olaitan A.O.,Aix - Marseille University | Diene S.M.,Aix - Marseille University | Kempf M.,Angers University Hospital Center | Berrazeg M.,Aix - Marseille University | And 17 more authors.
International Journal of Antimicrobial Agents | Year: 2014

The emergence of colistin-resistant Klebsiella pneumoniae (CRKP) is a major public health concern worldwide. In this study, the prevalence and molecular basis of colistin resistance in CRKP isolated from healthy individuals and patients in Lao PDR, Thailand, Nigeria and France were investigated. Stool samples were screened by culture for the presence of colistin-resistant Klebsiella spp. Whole-genome sequence analysis was used to decipher the molecular mechanism of colistin resistance in a blaNDM-1-positive in vitro-selected CRKP mutant. PCR amplification and sequencing of the mgrB genetic environment was performed for all CRKP isolates as well as control colistin-susceptible K. pneumoniae (CSKP) isolates recovered from the same stools. A total of 869 stool samples were screened for colistin-resistant Klebsiella spp., yielding 32 CRKP and 2 colistin-resistant Klebsiella oxytoca. Comparative whole-genome sequence analysis revealed that an in vitro-selected CRKP mutant had an insertion sequence in its mgrB gene, as well as missense mutations in other selected clones. Of the 34 colistin-resistant Klebsiella spp. isolates, 14 (41.2%; 13 CRKP and 1 K. oxytoca) from the four countries also had various defects in their mgrB genes, but no such defects were found in the CSKP controls (P < 10-4). Few mutations were observed in pmrAB compared with mgrB among the CRKP isolates. The worldwide emergence of CRKP is a major public health concern. Detection and surveillance of such strains are warranted to prevent an uncontrollable pandemic. Inactivation of the PhoP/PhoQ regulator gene mgrB is associated with ≥40% of colistin resistance among the CRKP isolates observed in this study. © 2014 Elsevier B.V. and the International Society of Chemotherapy.

Pilosof S.,Ben - Gurion University of the Negev | Morand S.,CNRS Montpellier Institute of Evolutionary Sciences | Morand S.,Center dInfectiologie Christophe Merieux du Laos | Krasnov B.R.,Ben - Gurion University of the Negev | Nunn C.L.,Duke University
PLoS ONE | Year: 2015

Epidemiological networks are commonly used to explore dynamics of parasite transmission among individuals in a population of a given host species. However, many parasites infect multiple host species, and thus multi-host networks may offer a better framework for investigating parasite dynamics. We investigated the factors that influence parasite sharing - and thus potential transmission pathways - among rodent hosts in Southeast Asia. We focused on differences between networks of a single host species and networks that involve multiple host species. In host-parasite networks, modularity (the extent to which the network is divided into subgroups of rodents that interact with similar parasites) was higher in the multi-species than in the single-species networks. This suggests that phylogeny affects patterns of parasite sharing, which was confirmed in analyses showing that it predicted affiliation of individuals to modules. We then constructed "potential transmission networks" based on the host-parasite networks, in which edges depict the similarity between a pair of individuals in the parasites they share. The centrality of individuals in these networks differed between multi- and single-species networks, with species identity and individual characteristics influencing their position in the networks. Simulations further revealed that parasite dynamics differed between multi- and single-species networks. We conclude that multi-host networks based on parasite sharing can provide new insights into the potential for transmission among hosts in an ecological community. In addition, the factors that determine the nature of parasite sharing (i.e. structure of the host-parasite network) may impact transmission patterns. © 2015 Pilosof et al.

Paboriboune P.,Center dInfectiologie Christophe Merieux du Laos | Paboriboune P.,Montpellier University | Phoumindr N.,Health Science University | Borel E.,University of Lyon | And 9 more authors.
PLoS ONE | Year: 2014

Background: HIV infection is an emerging problem in Laos. We conducted the first prospective study on intestinal parasites, including opportunistic protozoa, in newly diagnosed HIV infected patients, with or without diarrhea. The aims were to describe the spectrum of infections, to determine their prevalence and to assess their associations with diarrhea, CD4 cell count, place of residence and living conditions. Methodology: One to three stool samples over consecutive days were obtained from 137 patients. The Kato thick smear method, formalin-ethyl concentration and specific stains for coccidia and microsporidia diagnosis were performed on 260 stool samples. Baseline characteristics regarding relevant demographics, place of residence and living conditions, clinical features including diarrhea, were collected using a standardized questionnaire. Principal Findings: The 137 patients were young (median age: 36 years) and severely immunocompromised (83.9% at WHO stage 3 or 4, median CD4 cell count: 41/mm3). Diarrhea was present in 43.0% of patients. Parasite infection was found in 78.8% of patients, infection with at least two species in 49.6%. Prevalence rates of protozoan and helminth infections were similar (54.7% and 58.4% respectively). Blastocystis sp. was the most frequent protozoa (26.3%). Cryptosporidium sp., Cytoisospora belli and microsporidia, found at low prevalence rates (6.6%, 4.4%, 2.9%, respectively), were described for the first time in Laos. Cryptosporidium sp. was associated with persistent diarrhea. Strongyloides stercoralis was the most prevalent helminth following Opisthorchis viverrini (20.4% and 47.5% respectively). The most immunocompromised patients, as assessed by a CD4 count ≤ 50 cells/mm3, were more likely to be infected with intestinal parasites. Conclusions/Significance: HIV infection was mainly diagnosed at an advanced stage of immunosuppression in Lao patients. Intestinal parasite infections were highly prevalent regardless of their diarrheal status. Opportunistic infections were reported. Improving the laboratory diagnosis of intestinal parasite infections and the knowledge on their local risk factors is warranted. © 2014 Paboriboune et al.

Law I.,World Health Organization | Sylavanh P.,National TB Control Programme | Bounmala S.,National TB Control Programme | Nzabintwali F.,National TB Control Programme | And 7 more authors.
Tropical Medicine and International Health | Year: 2015

Objective: The objective of the study was to measure the prevalence of bacteriologically confirmed pulmonary tuberculosis (TB) in Lao PDR in 2010-2011. Method: A nationwide, multistage cluster-sampled cross-sectional survey was undertaken in 2010-2011. All consenting participants ≥15 years were screened for pulmonary TB with chest X-ray and symptom questionnaire. Two sputum specimens for bacteriological examination by microscopy and culture were collected from those who screened positive. Prevalence was estimated using multiple imputation and inverse probability weighting methods. Results: Of 39 212 eligible participants from 50 clusters, 6290 participants provided at least one sputum sample for smear and culture. There were 237 bacteriologically confirmed pulmonary TB cases, 107 of which were smear-positive. Chest X-ray screening alone identified 230 (97.0%) cases compared with 118 (49.8%) by symptom screening alone. The estimated prevalence of smear-positive and bacteriologically confirmed TB in those ≥15 years was 278 per 100 000 (95%C.I. 199-356) and 595 per 100 000 (95%C.I. 457-733), respectively. Prevalence significantly increased with age and was higher in men than women. Conclusions: The prevalence of TB in Lao PDR is almost twice as high than previous estimates, with the greatest burden in the older population. Case detection efforts remain the primary goal of the national TB programme with case notifications being very low in comparison with the estimated number of prevalent cases. The survey observed major limitations with the diagnostic strategy of passive (symptom based) case finding that uses only direct smear microscopy for confirmation. © 2015 World Health Organization; licensed by Tropical Medicine & International Health Published by John Wiley & Sons Ltd.

PubMed | Mahidol University, Center dInfectiologie Christophe Merieux du Laos and Texas A&M University
Type: | Journal: Molecular phylogenetics and evolution | Year: 2016

Delimitation of species is still a necessity among parasitic pathogens especially where morphological characters provide limited discernibility. Identification of cryptic lineages (independently evolving lineages that are morphologically similar) is critical as there could be lineage-specific traits that are of epidemiological importance. Angiostrongylus cantonensis is a zoonotic pathogen that can cause eosinophilic meningitis in humans. Recent reports of single marker sequence divergence hint at the potential for cryptic diversity in this lungworm. However, to definitively address if single marker divergence corresponds to independent evolving lineages, a multilocus approach is necessary. Using multilocus data, our goal was to determine if there were cryptic lineages within Thailand, a country plagued by several outbreaks and isolated cases of A. cantonensis infection. We analyzed the genetic structure of A. cantonensis samples collected from snails, Achatina fulica, across provinces in Thailand. Multilocus data (mitochondrial sequence data and 12 nuclear microsatellites) and individual based analyses were used to test for cryptic lineages. We found strong linkage disequilibrium patterns between mitochondrial haplotypes and nuclear-identified genetic clusters. There were clearly two divergent and independent clades. Moreover, within each clade, the data suggested additional substructure where individual provinces were likely to harbor unique genetic clusters. The results indicate there are at minimum two and possibly up to eight cryptic lineages within the assumed single species of A. cantonensis. Importantly, the two main clades do not show geographic affiliation and can be found in sympatry. With recent studies highlighting A. cantonensis strain diversity in pathogenicity and infectivity, it will be important to determine if these critical epidemiological traits are associated with specific lineages.

Olaitan A.O.,Aix - Marseille University | Morand S.,Montpellier University | Morand S.,Center dInfectiologie Christophe Merieux du Laos | Rolain J.-M.,Aix - Marseille University
International Journal of Antimicrobial Agents | Year: 2016

Colistin is currently regarded as one of the 'last-resort' antibiotics used for the treatment of critical infections caused by multidrug-resistant Gram-negative pathogens. There have been numerous reports of the emergence of colistin resistance in patients, most of whom had previously received colistin therapy or with acquisition via nosocomial transmission. However, there are also ample reports of colistin resistance in humans who have not received the drug previously or without nosocomial transmission. We have also observed a similar occurrence in our study involving colistin resistance from several countries along with a similar phenomenon being reported by researchers. The observation of colistin resistance in humans without prior colistin exposure is of particularly great clinical importance and concern because of the current importance of colistin in clinical medicine. Colistin use and colistin-resistant bacteria in animals have been recently reported, suggesting that animals could also be a source of transmission of colistin-resistant bacteria to humans. This is a real worry and calls for clinicians to be aware and vigilant of this phenomenon and of the possibility of independent resistance to colistin in some patients. © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Gauthier M.,Fondation Merieux Center International Of Recherche En Infectiologie Ciri | Bidault F.,Fondation Merieux Center International Of Recherche En Infectiologie Ciri | Mosnier A.,Fondation Merieux Center International Of Recherche En Infectiologie Ciri | Bablishvili N.,National Center for Tuberculosis and Lung Disease | And 7 more authors.
Journal of Clinical Microbiology | Year: 2015

The emergence of drug-resistant forms of tuberculosis (TB) represents a major public health concern. Understanding the transmission routes of the disease is a key factor for its control and for the implementation of efficient interventions. Mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) marker typing is a well-described method for lineage identification and transmission tracking. However, the conventional manual genotyping technique is cumbersome and time-consuming and entails many risks for errors, thus hindering its implementation and dissemination. We describe here a new approach using the QIAxcel system, an automated high-throughput capillary electrophoresis system that also carries out allele calling. This automated method was assessed on 1,824 amplicons from 82 TB isolates and tested with sets of markers of 15 or 24 loci. Overall allele-calling concordance between the methods from 140 to 1,317 bp was 98.9%. DNA concentrations and repeatability and reproducibility performances showed no biases in allele calling. Furthermore, turnaround time using this automated system was reduced by 81% compared to the conventional manual agarose gel method. In sum, this new automated method facilitates MIRU-VNTR genotyping and provides reliable results. Therefore, it is well suited for field genotyping. The implementation of this method will help to achieve accurate and cost-effective epidemiological studies, especially in countries with a high prevalence of TB, where the high number of strains complicates the surveillance of circulating lineages and requires efficient interventions to be carried out in an urgent manner. © 2015, American Society for Microbiology. All Rights Reserved.

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