Le complexe taeniase/cysticercose : la phylogénie et l’évolution de Taenia solium et la biologie moléculaire appliquée au diagnostic

Taenia soliumis responsible for two distinct diseases in humans: taeniasis and cysticercosis. The complex Taeniasis/Cysticercosis has long been investigated because of the impact of the parasite on the human and pig populations.We wanted to study this complex from the angle of the parasite-host system (intermediate host, definitive host and parasite). The main objective of this work is to deepen knowledge of this complex to lead to improved diagnosis of neurocysticercosis. We work primarily on the genetic variation of Taenia solium in different countries: Madagascar, Cameroon and Mexico. We have confirmed the existence of two genotypes that reflect the particular biogeography of T. solium. We have determined the specific nucleotide signatures allowing their distinction. We then have estimated the dates of divergence of these groups to establish the biogeographical origin of the parasite, particularly in Madagascar. The observations from T. solium were correlated with historical, genetic and archaeological data. We then expanded our study to two other Taenia that infect humans: T. saginata and T. asiatica. The origin of these parasites in humans has been studied as well as the events leading to host’s switching. We have issued several hypotheses about the major events of diversification of these parasites. Specifically, we examined their relationship with their hosts and the influence they had on the current status of these three Taenia.The second aspect of this work focuses on the diagnosis of neurocysticercosis. The research was conducted on a Mexican population where cysticercosis is endemic. We compared all biological tests currently available: ELISA for the detection of antibodies, ELISA for the detection of antigen, EITB and PCR. These data were compared with clinical, epidemiologic and imaging information. We determined the intrinsic parameters (specificity and sensitivity) of each method and the correlation between the different tests. We have also studied the effect of CSF inflammation on test results. We propose to incorporate the PCR as a diagnostic tool for neurocysticercosis in combination with others tests.Taenia soliumest responsable de deux maladies distinctes chez l’homme : la taeniase et la cysticercose. Le complexe Taeniase/Cysticercose est depuis longtemps étudié du fait de l’impact du parasite sur les populations humaines et porcines.Nous avons voulu étudier ce complexe du point de vue du système hôte-parasite (hôte intermédiaire, hôte définitif et parasite). L’objectif principal de ce travail est d’approfondir les connaissances de ce complexe afin d’aboutir à l’amélioration du diagnostic de la neurocysticercose.Nous avons travaillé en premier lieu sur les variations génétiques de Taenia solium dans différents pays : Madagascar, Cameroun et Mexique. Nous avons confirmé l’existence de deux génotypes qui reflètent la biogéographie particulière de T. solium. Nous avons pu déterminer des signatures nucléotidiques particulières permettant leur distinction. Nous avons par la suite estimé les dates de divergences de ces groupes afin d’établir l’origine biogéographique du parasite, notamment à Madagascar. Les observations faites à partir de T. solium ont été corrélées avec des données historiques, génétiques et archéologiques. Nous avons ensuite élargi notre étude aux deux autres Taenia qui parasitent l’homme : T. saginata et T. asiatica. L’origine de ces parasites chez l’homme a été étudiée ainsi que les évènements ayant conduit aux changements d’hôte. Nous avons donc émis plusieurs hypothèses quant aux évènements majeurs de diversification de ces parasites. Nous avons plus particulièrement étudié leur relation avec leurs hôtes et l’influence que ces derniers ont eu sur la situation actuelle de ces trois Taenia.Le second aspect de ce travail porte sur le diagnostic de la neurocysticercose. Les recherches ont été effectuées sur une population mexicaine où la cysticercose est endémique. Nous avons comparé tous les tests biologiques disponibles actuellement : ELISA détection d’anticorps, ELISA détection d’antigène, EITB et PCR. Ces données ont été combinées avec les informations cliniques, épidémiologiques et d’imagerie. Nous avons déterminé les paramètres intrinsèques (spécificité et sensibilité) de chaque méthode ainsi que la concordance entre les différents tests. Nous avons également étudié l’effet de l’inflammation du LCR sur ces paramètres. Nous proposons au final d’incorporer la PCR comme outil diagnostique de la neurocysticercose en combinaison avec les autres tests

Mycobacterium microti Infection in free-ranging wild boar, Spain, 2017-2019

Mycobacterium microti is a member of the Mycobacterium tuberculosis complex that causes pathology in many mammals. M. microti infections have been found in some countries in Europe. We report an outbreak of tuberculosis caused by M. microti in wild boars in Spain.info:eu-repo/semantics/publishedVersio

Diversity of nontuberculous mycobacteria isolated from animal samples

Limited data is available regarding the epidemiology of the nontuberculous mycobacteria (NTM) in Romania, in both human and veterinary medicine. The objective of the present study was the identification and characterization of the Mycobacterium avium complex species isolated from backyard poultry and ruminant samples. The molecular identification and genotyping was performed in ANSES, Laboratory for Animal Health, Maisons-Alfort, France, by real time PCR, with a wide range of targets: hsp65, IS6110, IS1081, IS1245, IS901 and MIRU-VNTR. M. avium avium and M. avium paratuberculosis were the two species identified. Five different profiles were obtained through genotyping, four of which had corresponding INMV (INRA Nouzilly MIRU-VNTR) profiles: INMV 2, INMV 67, INMV 99 and INMV 100. The technique differentiated between the M. avium paratuberculosis isolated from sheep and cattle and expressed a high discriminatory power, proving to be extremely useful for assessing the genetic diversity of the tested animal origin samples and providing comparable information on the general structure and main pathogens belonging to MAC

Differences in skin test reactions to official and defined antigens in guinea pigs exposed to non-tuberculous and tuberculous bacteria

The single and comparative intradermal tuberculin tests (SITT and CITT) are official in vivo tests for bovine tuberculosis (TB) diagnosis using bovine and avian purified protein derivatives (PPD-B and PPD-A). Infection with bacteria other than Mycobacterium tuberculosis complex (MTC) can result in nonspecific reactions to these tests. We evaluated the performance of the skin test with PPDs and new defined antigens in the guinea pig model. A standard dose (SD) of Rhodococcus equi, Nocardia sp., M. nonchromogenicum, M. monacense, M. intracellulare, M. avium subsp. paratuberculosis, M. avium subsp. avium, M. avium subsp. hominissuis, M. scrofulaceum, M. persicum, M. microti, M. caprae and M. bovis, and a higher dose (HD) of M. nonchromogenicum, M. monacense, M. intracellulare, M. avium subsp. paratuberculosis were tested using PPD-B, PPD-A, P22, ESAT-6-CFP-10-Rv3615c peptide cocktail long (PCL) and fusion protein (FP). The SD of R. equi, Nocardia sp., M. nonchromogenicum, M. monacense, M. intracellulare and M. avium subsp. paratuberculosis did not cause any reactions. The HD of M. nonchromogenicum, M. monacense, M. intracellulare, and M. avium subsp. paratuberculosis and the SD of M. avium subsp. hominissuis, M. scrofulaceum and M. persicum, caused nonspecific reactions (SIT). A CITT interpretation would have considered M. avium complex and M. scrofulaceum groups negative, but not all individuals from M. nonchromogenicum HD, M. monacense HD and M. persicum SD groups. Only animals exposed to M. bovis and M. caprae reacted to PCL and FP. These results support the advantage of complementing or replacing PPD-B to improve specificity without losing sensitivity.info:eu-repo/semantics/publishedVersio

Lack of detection of Mycobacterium microti infection in wild rodents from a free-ranging wild boar outbreak area

Altres ajuts: acords transformatius de la UAB. Departament d'Acció Climàtica, Agricultura i Agenda Rural de la Generalitat de Catalunya EFA357/INNOTUB (Program Interreg POCTEFA 2004-2020)Wild small rodents are considered the natural reservoirs of Mycobacterium microti, a member of the Mycobacterium tuberculosis complex (MTBC) that can cause tuberculosis (TB) in humans and animals, as well as interfere with current tuberculosis eradication plans in livestock. A cross-sectional study was carried out in the Catalan Pyrenees (Iberian Peninsula) in an area where M. microti was previously isolated from wild boars, to evaluate the role of micromammals in the epidemiology of this outbreak. A total of 350 wild rodents were necropsied (306 Murinae and 44 Arvicolinae) in spring and autumn during two consecutive natural years. Tissues were analyzed by histopathology to look for TB-like lesions and by qPCR and culture to detect MTBC. Sera were analyzed by MTBC-specific ELISA. No evidence of TB infection in wild rodents was confirmed. Results suggest that small rodents did not play a role in the epidemiology of M. microti in the area. The source of this mycobacterium remains unknown, but previous detections of M. microti in various species in southern France suggest the movements of wild boars across the French Pyrenees as the most likely origin of the outbreak detected in the Iberian Peninsula

Experimental Infection of Captive Red Foxes (Vulpes vulpes) with Mycobacterium bovis

[EN] In Europe, animal tuberculosis (TB) due to Mycobacterium bovis involves multi-host communities that include cattle and wildlife species, such as wild boar (Sus scrofa), badgers (Meles meles) and red deer (Cervus elaphus). Red fox (Vulpes vulpes) infections have also been recently reported in some TB endemic regions in the Iberian Peninsula and France, with some of the infected animals shedding M. bovis in urine and feces. In order to understand the pathogenesis of M. bovis infection in foxes and the associated risk of transmission, 12 captive foxes (6 females and 6 males) were inoc-ulated orally with 2 × 107 colony-forming units of a French field isolate of M. bovis. Clinical samples (urine, feces and oropharyngeal swabs) were collected every four weeks and tested for molecular diagnosis and bacteriology. Serological responses were measured by IDEXX M. bovis Ab Test and Multi Antigen Print Immunoassay (MAPIA). At a post-mortem examination performed 12 weeks post infection (wpi), tissues were tested for the presence of M. bovis and associated gross and microscopic TB-like lesions. M. bovis was detected by PCR in bladder swabs of 3 animals at 12 wpi. It was also detected pre-mortem at different time points of the experiment in the oropharyngeal mu-cus of three individuals and in the feces of nine foxes, with two of them confirmed by bacteriology. All 12 foxes had at least 4 PCR positive samples (out of the 23 tested), and all but 1 fox had at least 1 culture positive sample. The culture negative fox was PCR positive in both retropharyngeal and mesenteric lymph nodes, in line with the results of the other animals. Seroconversion was observed in all foxes except one during the experiment, and in nine at the final time point. No gross visible lesions were found in any animal at the post-mortem examination. The histology showed small granulomas within the lymph nodes, tonsils, liver and lungs from eight animals, with the presence of few acid-fast bacilli. These results confirmed that all orally-infected foxes developed mild TB lesions but they were able to shed mycobacteria in about 75% of cases, 1 month post-infection (9 out 12 foxes). These results show that it is possible to induce typical TB infection experimentally in captive foxes, with measurable M. bovis excretion; such an experimental system could be useful for future evaluations of diagnostics and vaccines in this speciesSIThe French Ministry of Agriculture mainly financed the sampling and the analyses in the framework of the RFSA call on TB projects (Anses-DGAl credit agreement RFSA 2017-326). The animals and the running cost of the BSL3 facilities and technical resources were financed by the European Commission in the context of Horizon 2020?Vetbionet Transnational Access Activities (TNA) call. This work is also partially the result of the I+D+i research project RTI2018-096010-B-C21, funded by the Spanish MCIN/AEI/10.13039/501100011033/ Ministry of Science, Innovation and the European Regional Development Funds (FEDER Una manera de hacer Europa), and of PCTI 2021? 2023 (GRUPIN: IDI2021-000102) funded by Principado de Asturias and FEDE

Phylogenomic Perspective on a Unique Mycobacterium bovis Clade Dominating Bovine Tuberculosis Infections among Cattle and Buffalos in Northern Brazil.

Lack of routine surveillance in countries endemic for bovine tuberculosis (TB) and limited laboratory support contributes to the inability to differentiate the Mycobacterium tuberculosis Complex species, leading to an underestimated burden of the disease. Here, Whole-Genome Sequencing of Mycobacterium bovis isolated from tissues with TB-like lesions obtained from cattle and buffalos at Marajó Island, Brazil, demonstrates that recent transmission of M. bovis is ongoing at distinct sites. Moreover, the M. bovis epidemiology in this setting is herein found to be dominated by an endemic and unique clade composed of strains evolved from a common ancestor that are now genetically differentiated from other M. bovis clades. Additionally, envisioning a rapid strain differentiation and tracing across multiple settings, 28 globally validated strain-specific SNPs were identified, three of which considered as robust markers for the M. bovis Marajó strain. In conclusion, this study contributes with data regarding the identification of a novel M. bovis phylogenetic clade responsible for ongoing transmission events in both cattle and buffalo species in Brazil, provides a framework to investigate the dissemination of this highly prevalent strain and, holds the potential to inform TB control strategies that may help to prevent the spread of bovine and zoonotic TB

Staphylococcus aureus infective endocarditis versus bacteremia strains: Subtle genetic differences at stake

AbstractInfective endocarditis (IE)(1) is a severe condition complicating 10–25% of Staphylococcus aureus bacteremia. Although host-related IE risk factors have been identified, the involvement of bacterial features in IE complication is still unclear. We characterized strictly defined IE and bacteremia isolates and searched for discriminant features. S. aureus isolates causing community-acquired, definite native-valve IE (n=72) and bacteremia (n=54) were collected prospectively as part of a French multicenter cohort. Phenotypic traits previously reported or hypothesized to be involved in staphylococcal IE pathogenesis were tested. In parallel, the genotypic profiles of all isolates, obtained by microarray, were analyzed by discriminant analysis of principal components (DAPC)(2). No significant difference was observed between IE and bacteremia strains, regarding either phenotypic or genotypic univariate analyses. However, the multivariate statistical tool DAPC, applied on microarray data, segregated IE and bacteremia isolates: IE isolates were correctly reassigned as such in 80.6% of the cases (C-statistic 0.83, P<0.001). The performance of this model was confirmed with an independent French collection IE and bacteremia isolates (78.8% reassignment, C-statistic 0.65, P<0.01). Finally, a simple linear discriminant function based on a subset of 8 genetic markers retained valuable performance both in study collection (86.1%, P<0.001) and in the independent validation collection (81.8%, P<0.01). We here show that community-acquired IE and bacteremia S. aureus isolates are genetically distinct based on subtle combinations of genetic markers. This finding provides the proof of concept that bacterial characteristics may contribute to the occurrence of IE in patients with S. aureus bacteremia

Transmission Network of Deer-Borne Mycobacterium bovis Infection Revealed by a WGS Approach

Bovine tuberculosis (TB) is a zoonotic disease, mainly caused by Mycobacterium bovis. France was declared officially TB free in 2001, however, the disease persists in livestock and wildlife. Among wild animals, deer are particularly susceptible to bovine TB. Here, a whole genome sequence (WGS) analysis was performed on strains with the same genetic profile—spoligotype SB0121, Multiple Loci VNTR Analysis (MLVA) 6 4 5 3 11 2 5 7—isolated from different types of outbreaks, including from deer or cattle herds, or zoological or hunting parks where the presence of infected deer was a common trait in most of them. The results of the phylogeny based on the SNP calling shows that two sub-clusters co-exist in France, one related to deer bred to be raised as livestock, and the other to hunting parks and zoos. The persistence over almost 30 years of sporadic cases due to strains belonging to these clusters highlights the deficiency in the surveillance of captive wildlife and the need for better monitoring of animals, especially before movement between parks or herds