Infection with Mycobacterium microti in animals in France.

We describe here 35 animal cases of tuberculosis due to Mycobacterium microti in France (2002-2014). Recently, molecular tools that overcome the difficulty of confirming infection by this potentially zoonotic agent have revealed an increasing number of cases, suggesting that its prevalence may have been underestimated.

Determination of genotypic diversity of Mycobacterium avium subspecies from human and animal origins by mycobacterial interspersed repetitive-unit-variable-number tandem-repeat and IS1311 restriction fragment length polymorphism typing methods.

Members of the Mycobacterium avium complex (MAC) are ubiquitous bacteria that can be found in water, food, and other environmental samples and are considered opportunistic pathogens for numerous animal species, mainly birds and pigs, as well as for humans. We have recently demonstrated the usefulness of a PCR-based mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) typing for the molecular characterization of M. avium subsp. paratuberculosis and M. avium strains exclusively isolated from AIDS patients. In the present study we extended our analysis, based on eight MIRU-VNTR markers, to a strain collection comprehensively comprising the other M. avium subspecies, including M. avium subsp. avium, M. avium subsp. hominissuis, and M. avium subsp. silvaticum, isolated from numerous animal species, HIV-positive and HIV-negative humans, and environmental sources. All strains were fully typeable, with the discriminatory index being 0.885, which is almost equal to that obtained by IS1311 restriction fragment length polymorphism (RFLP) typing as a reference. In contrast to IS1311 RFLP typing, MIRU-VNTR typing was able to further discriminate M. avium subsp. avium strains. MIRU-VNTR alleles strongly associated with or specific for M. avium subspecies were detected in several markers. Moreover, the MIRU-VNTR typing-based results were consistent with a scenario of the independent evolution of M. avium subsp. avium/M. avium subsp. silvaticum and M. avium subsp. paratuberculosis from M. avium subsp. hominissuis, previously proposed on the basis of multilocus sequence analysis. MIRU-VNTR typing therefore appears to be a convenient typing method capable of distinguishing the three main subspecies and strains of the complex and providing new epidemiological knowledge on MAC.

Mycobacterium bovis in wildlife in France.

In early 2001, tuberculosis-like lesions were detected in three hunter-killed red deer (Cervus elaphus) in the Brotonne Forest (Normandy, France), and Mycobacterium bovis was isolated. In subsequent hunting seasons, two surveys were conducted in the area. In the first survey (2001-02 hunting season), nine (13%) of 72 red deer sampled were positive for M. bovis. In the 2005-06 hunting season, the prevalence of M. bovis infection increased to 24% (chi2=3.85, df=1, P=0.05; 33 positive among 138 sampled). The prevalence remained stable in juveniles, but it increased significantly in adults: from 13% in 2001-02 to 32% in 2005-06 (chi2=5.13, df=1, P=0.02). Wild boar (Sus scrofa) were heavily infected in both surveys. One roe deer (Capreolus capreolus) and one red fox (Vulpes vulpes) also tested positive in the second survey. Mycobacterium bovis was not isolated from Eurasian badgers (Meles meles). Spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat analysis demonstrated that all M. bovis strains isolated from wildlife were of the same genotype. Thus, the wildlife outbreak involved only a single strain, and this strain was the same as that circulating in nearby cattle herds since 1995. Sensitivity, specificity, and predictive values of the presence of macroscopic lesions as a diagnostic criterion were evaluated from the data obtained from red deer. Necropsy seems to be satisfactory as a routine tool to monitor the disease in wild red deer populations in which bovine tuberculosis has become established.

Second line molecular diagnosis for bovine tuberculosis to improve diagnostic schemes.

Surveillance of bovine tuberculosis (bTB) is partly based on the sanitary inspection of carcasses at the abattoir to detect bTB-like lesions which, in compliance with EU recommendations, are analysed by bacteriology and histopathology to disclose Mycobacterium bovis (or M. caprae) infection. Moreover, since 2012, a PCR method with similar sensitivity and specificity values of histopathology and bacteriology respectively is additionally employed in France, partially compensating for the weaknesses of classical diagnostic methods. We analysed a collection of bTB-like lesions from cattle presenting positive histological results albeit with negative PCR results. We present here the results of these samples, recovered from 292 animals culled between 2013 and 2016, analysed with a second line molecular diagnosis approach that consists in a combination of PCRs targeting the M. tuberculosis-M. avium complexes as well as the Mycobacterium genus and sequencing of hsp65 gene. These molecular analyses disclosed to identify the presence of non-tuberculous bacteria which could be responsible for most of these non-specific TB lesions: non tuberculous mycobacteria (24%) or Actinomycetales (56%) such as Rhodococcus equi (53%); 24% of the samples were negative. M. bovis -or any other MTBC members- was neither detected by molecular methods nor isolated in any of them at the end of the 3 months of culture. In conclusion, these results highlight the lack of specificity of histopathology and the usefulness of a first line PCR with a second line molecular diagnostic test to circumvent it. This diagnostic strategy makes it possible to reduce the number of suspect bTB cases raised at the abattoir or shortening their lock-up periods. By simplifying diagnostic schemes, the use of this tool could improve bTB surveillance and make eradication programs more efficient in the future.

Draft Genome Sequences of Three Mycobacterium bovis Strains Identified in Cattle and Wildlife in France.

Mycobacterium bovis is the etiologic agent of bovine tuberculosis, a chronic infectious disease affecting livestock, wild animals, and sometimes humans. We report here three draft genome sequences of Mycobacterium bovis strains of spoligotypes SB0821 and SB0134, isolated from wildlife but circulating in wildlife-livestock multihost systems, and SB0121, circulating exclusively in cattle.

Draft Genome Sequence of Mycobacterium bovis Strain D-10-02315 Isolated from Wild Boar.

Mycobacterium bovis is the etiologic agent of bovine tuberculosis, a chronic infectious disease, affecting livestock, wild animals, and sometimes humans. We report the draft genome sequence of a Mycobacterium bovis strain isolated from wild boar of spoligotype SB0120 (or BCG-like) also present in wildlife-livestock multi-host systems.

MIRU-VNTR allelic variability depends on Mycobacterium bovis clonal group identity.

The description of the population of M. bovis strains circulating in France from 1978 to 2013 has highlighted the discriminating power of the MLVA among predominant spoligotype groups. In the present study we aimed to characterize clonal groups via MLVA and to better understand the strain's population structure. MLVA was performed with eight MIRU-VNTR loci, most of them defined by the Venomyc European consortium. The discriminatory index of each MLVA loci was calculated for SB0120, SB0134, SB0121 and the "F4-family", the main spoligotype groups in France. Differences in global DI per spoligotype, but also by locus within each spoligotype, were observed, which strongly suggest the clonal complex nature of these major groups. These MLVA results were compared to those of other European countries where strain collections had been characterized (Spain, Portugal, Italy, Northern Ireland and Belgium). Overall, QUB 3232 and ETR D are respectively the most and the least discriminative loci, regardless of the strains geographical origin. However, marked DI differences are observed in the rest of the MIRU-VNTR loci, again highlighting that strain genetic variability in a country depends on the dominant existing clonal complexes. A web application for M. bovis, including spoligotyping and MIRU-VNTR typing data, was developed to allow inter-laboratory comparison of field isolates. In conclusion, combination of typing methods is required for M. bovis optimum discrimination and differentiation of groups of strains. Thus, the loci employed for MLVA in a country should be those which are the most discriminative for the clonal complexes which characterize their M. bovis population.

Genetic evolution of Mycobacterium bovis causing tuberculosis in livestock and wildlife in France since 1978.

To study the dynamics of bovine tuberculosis (bTB) in France, 4,654 M. bovis strains isolated mainly from livestock and wildlife since 1978 were characterized by spoligotyping and MLVA based on MIRU-VNTR. In our study spoligotyping allowed the discrimination of 176 types although 3 spoligotypes are predominant and account for more than half of the total strain population: SB0120 (26%), SB0134 (11%) and SB0121 (6%). In addition, 11% of the isolates, principally from Southern France, showing close spoligotypes and MIRU-VNTR types have been gathered in a family designated as the "F4-family". MLVA typing allowed extensive discrimination, particularly for strains with predominant spoligotypes, with a total of 498 genotypes, several of which were highly regionalized. The similarity of the strains' genetic relationships based on spoligotyping and MIRU-VNTR markers supports the co-existence of different clonal populations within the French M. bovis population. A genetic evolution of the strains was observed both geographically and in time. Indeed, as a result of the reduction of bTB due to the national control campaigns, a large reduction of the strains' genetic variability took place in the last ten years. However, in the regions were bTB is highly prevalent at present, cases in both livestock and in wildlife are due to the spread of unique local genotype profiles. Our results show that the highly discriminating genotyping tools used in this study for molecular studies of bTB are useful for addressing pending questions, which would lead to a better insight into the epidemiology of the disease, and for finding proper solutions for its sustainable control in France.

European 1: a globally important clonal complex of Mycobacterium bovis.

We have identified a globally important clonal complex of Mycobacterium bovis by deletion analysis of over one thousand strains from over 30 countries. We initially show that over 99% of the strains of M. bovis, the cause of bovine tuberculosis, isolated from cattle in the Republic of Ireland and the UK are closely related and are members of a single clonal complex marked by the deletion of chromosomal region RDEu1 and we named this clonal complex European 1 (Eu1). Eu1 strains were present at less than 14% of French, Portuguese and Spanish isolates of M. bovis but are rare in other mainland European countries and Iran. However, strains of the Eu1 clonal complex were found at high frequency in former trading partners of the UK (USA, South Africa, New Zealand, Australia and Canada). The Americas, with the exception of Brazil, are dominated by the Eu1 clonal complex which was at high frequency in Argentina, Chile, Ecuador and Mexico as well as North America. Eu1 was rare or absent in the African countries surveyed except South Africa. A small sample of strains from Taiwan were non-Eu1 but, surprisingly, isolates from Korea and Kazakhstan were members of the Eu1 clonal complex. The simplest explanation for much of the current distribution of the Eu1 clonal complex is that it was spread in infected cattle, such as Herefords, from the UK to former trading partners, although there is evidence of secondary dispersion since. This is the first identification of a globally dispersed clonal complex M. bovis and indicates that much of the current global distribution of this important veterinary pathogen has resulted from relatively recent International trade in cattle.