First isolation and characterization of Brucella microti from wild boar

Molecular typing methods to characterize Brucella spp. from animals: A review

Brucellosis is an infectious disease of animals that can infect humans. The disease causes significant economic losses and threatens human health. A timely and accurate disease diagnosis plays a vital role in the identification of brucellosis. In addition to traditional diagnostic methods, molecular methods allow diagnosis and typing of the causative agent of brucellosis. This review will discuss various methods, such as Bruce-ladder, Suiladder, high-resolution melt analysis, restriction fragment length polymorphism, multilocus sequence typing, multilocus variable-number tandem repeat analysis, and whole-genome sequencing single-nucleotide polymorphism, for the molecular typing of Brucella and discuss their advantages and disadvantages.

Risks of Brucella spp. Infection in Dogs

Dogs are known to be susceptible to different Brucella species, even though canine brucellosis is usually associated with B [...].

Zoonotic Potential of Brucella microti

Background: Brucella microti is a pathogen of rodents and wild mammals. Here, we report the first probable infection with B. microti in a mammalogist. Methods: In the study, we provided complete clinical description as well as laboratory analysis of probable human infection caused by B. microti. Results: Considering the clinical course of the infection, the obvious epidemiological link (a bite by an infected rodent), the isolation of a pathogen from a sick vole that was affected by clinical infection with B. microti, and the specific serological response (slow agglutination test) in human patient, we can conclude that the human disease described here was probably caused by B. microti, an emerging bacterial pathogen transmitted by rodents. Conclusion: Rodents and other wildlife need to be monitored not only for established zoonotic agents such as hantaviruses, lymphocytic choriomeningitis virus, Leptospira spp., Francisella tularensis, but also for Brucella microti and other atypical rodent-borne brucellae.

White-Toothed Shrews (Genus Crocidura): Potential Reservoirs for Zoonotic Leptospira spp. and Arthropod-Borne Pathogens?

Three species of white-toothed shrews of the order Eulipotyphla are present in central Europe: the bicolored (Crocidura leucodon), greater (Crocidura russula) and lesser (Crocidura suaveolens) white-toothed shrews. Their precise distribution in Germany is ill-defined and little is known about them as reservoirs for zoonotic pathogens (Leptospira spp., Coxiella burnetii, Brucella spp., Anaplasma phagocytophilum, Babesia spp., Neoehrlichia mikurensis and Bartonella spp.). We investigated 372 Crocidura spp. from Germany (n = 341), Austria (n = 18), Luxembourg (n = 2) and Slovakia (n = 11). West European hedgehogs (Erinaceus europaeus) were added to compare the presence of pathogens in co-occurring insectivores. Crocidura russula were distributed mainly in western and C. suaveolens mainly in north-eastern Germany. Crocidura leucodon occurred in overlapping ranges with the other shrews. Leptospira spp. DNA was detected in 28/227 C. russula and 2/78 C. leucodon samples. Further characterization revealed that Leptospira kirschneri had a sequence type (ST) 100. Neoehrlichia mikurensis DNA was detected in spleen tissue from 2/213 C. russula samples. Hedgehogs carried DNA from L. kirschneri (ST 100), L. interrogans (ST 24), A. phagocytophilum and two Bartonella species. This study improves the knowledge of the current distribution of Crocidura shrews and identifies C. russula as carrier of Leptospira kirschneri. However, shrews seem to play little-to-no role in the circulation of the arthropod-borne pathogens investigated.

Cell and Tissue Tropism of Brucella spp

Brucella spp. are facultatively intracellular bacteria that can infect, survive, and multiply in various host cell types in vivo and/or in vitro. The genus Brucella has markedly expanded in recent years with the identification of novel species and hosts, which has revealed additional information about the cell and tissue tropism of these pathogens. Classically, Brucella spp. are considered to have tropism for organs that contain large populations of phagocytes such as lymph nodes, spleen, and liver, as well as for organs of the genital system, including the uterus, epididymis, testis, and placenta. However, experimental infections of several different cultured cell types indicate that Brucella may actually have a broader cell tropism than previously thought. Indeed, recent studies indicate that certain Brucella species in particular hosts may display a pantropic distribution in vivo. This review discusses the available knowledge on cell and tissue tropism of Brucella spp. in natural infections of various host species, as well as in experimental animal models and cultured cells.

Brucellosis in the Brazilian Pantanal wetland: threat to animal production and wildlife conservation

This review was performed to gather knowledge about brucellosis in livestock and wildlife in the Brazilian Pantanal, a biome with a huge biodiversity and extensive livestock production. Following the preferred reporting items for narrative review guidelines and using the terms "Brucella" and "Pantanal," we explored the PubMed, SciELO, Jstor, Science Direct, and Scholar Google databases. Information on host species, diagnostic test, number of positive animals, and positivity rates were acquired. Articles dating from 1998 to 2022 registered 14 studies including cattle, dogs, and the following wildlife species: Ozotoceros bezoarticus, Sus scrofa, Tayassu peccari, Nasua nasua, Cerdocyon thous, Panthera onca, Dasypus novemcintus, Cabassous unicinctus, Euphractus sexcinctus, Priodontes maximus, Myrmecophaga tridactyla and Hydrochoerus hydrochaeris. Brucella occurrence in cattle was demonstrated through the serological confirmatory test 2-mercaptoetanol. Molecular diagnosis detected Brucella abortus in dogs, smooth Brucella in O. beoarticus, and Brucella spp. in T. peccari. Cattle may have a pivotal importance in maintenance and spreading of Brucella spp. due to their high population density, environmental contamination from abortion of infected cows, and eventual excretion of B. abortus S19 strain from vaccinated heifers. The occurrence of Brucella spp. in O. bezoarticus and T. peccari represent a risk for wildlife conservation. These data indicate that Brucella spp. are enzootic in the Pantanal wetland, sustained by a reservoir system including domestic and wild mammals. Due to marked seasonality and large populations of wildlife species sharing same environments with livestock, brucellosis acquires great complexity in Pantanal and, therefore, must be analyzed considering both animal production and conservation.

First Report of Brucella Seroprevalence in Wild Boar Population in Serbia

Brucellosis is one of the most important bacterial zoonotic diseases worldwide, characterized in domestic animals by long-term reproductive disorders. As known, wild boars (Sus scrofa) are natural hosts for Brucella suis biovar 2, in which the infection passes in inapparent form, increasing the pathogen transmission risk to domestic pigs, other domestic animals and humans. So far, no studies regarding brucellosis in wild boars in Serbia have been published. During the hunting season 2020/2021, 480 sera of wild boars living in Serbia were collected and tested for the presence of anti-Brucella antibodies. For the serological survey, the Rose Bengal Test (RBT) and competitive enzyme-linked immunosorbent assay (c-ELISA) were used. Of the 480 sera, 45 sera tested positive, indicating the acquired Brucella seroprevalence in wild boars of 9.4%. The greatest numbers of Brucella seropositive animals were detected in the eastern parts of the country and in one of the central districts, i.e., Pomoravski, Branicevski, Borski and Juznobanatski. This study provides the first data regarding brucellosis in the wild boar population in Serbia, revealing the seroprevalence of Brucella, thus indicating that wild boars as natural hosts and/or vectors of Brucella likely present a risk for the infection of other animals.

The Retrospective on Atypical Brucella Species Leads to Novel Definitions

The genus Brucella currently comprises twelve species of facultative intracellular bacteria with variable zoonotic potential. Six of them have been considered as classical, causing brucellosis in terrestrial mammalian hosts, with two species originated from marine mammals. In the past fifteen years, field research as well as improved pathogen detection and typing have allowed the identification of four new species, namely Brucella microti, Brucella inopinata, Brucella papionis, Brucella vulpis, and of numerous strains, isolated from a wide range of hosts, including for the first time cold-blooded animals. While their genome sequences are still highly similar to those of classical strains, some of them are characterized by atypical phenotypes such as higher growth rate, increased resistance to acid stress, motility, and lethality in the murine infection model. In our review, we provide an overview of state-of-the-art knowledge about these novel Brucella sp., with emphasis on their phylogenetic positions in the genus, their metabolic characteristics, acid stress resistance mechanisms, and their behavior in well-established in cellulo and in vivo infection models. Comparison of phylogenetic classification and phenotypical properties between classical and novel Brucella species and strains finally lead us to propose a more adapted terminology, distinguishing between core and non-core, and typical versus atypical brucellae, respectively.

High-Resolution Melting PCR as Rapid Genotyping Tool for Brucella Species

Brucella sp. are the causative agents of brucellosis. One of the main characteristics of the Brucella genus concerns its very high genetic homogeneity. To date, classical bacteriology typing is still considered as the gold standard assay for direct diagnosis of Brucella. Molecular approaches are routinely used for the identification of Brucella at the genus level. However, genotyping is more complex, and to date, no method exists to quickly assign a strain into species and biovar levels, and new approaches are required. Next generation sequencing (NGS) opened a new era into the diagnosis of bacterial diseases. In this study, we designed a high-resolution melting (HRM) method for the rapid screening of DNA and direct assignment into one of the 12 species of the Brucella genus. This method is based on 17 relevant single nucleotide polymorphisms (SNPs), identified and selected from a whole genome SNP (wgSNP) analysis based on 988 genomes (complete and drafts). These markers were tested against the collection of the European Reference Laboratory (EU-RL) for brucellosis (1440 DNAs extracted from Brucella strains). The results confirmed the reliability of the panel of 17 SNP markers, allowing the differentiation of each species of Brucella together with biovars 1, 2, and 3 of B. suis and vaccine strain Rev1 (B. melitensis) within 3 h, which is a considerable gain of time for brucellosis diagnosis. Therefore, this genotyping tool provides a new and quick alternative for Brucella identification based on SNPs with the HRM-PCR assay.

Comparative Genome-Wide Transcriptome Analysis of Brucella suis and Brucella microti Under Acid Stress at pH 4.5: Cold Shock Protein CspA and Dps Are Associated With Acid Resistance of B. microti

Brucellae are facultative intracellular coccobacilli causing brucellosis, one of the most widespread bacterial zoonosis affecting wildlife animals, livestock and humans. The genus Brucella comprises classical and atypical species, such as Brucella suis and Brucella microti, respectively. The latter is characterized by increased metabolic activity, fast growth rates, and extreme acid resistance at pH 2.5, suggesting an advantage for environmental survival. In addition, B. microti is more acid-tolerant than B. suis at the intermediate pH of 4.5. This acid-resistant phenotype of B. microti may have major implications for fitness in soil, food products and macrophages. Our study focused on the identification and characterization of acid resistance determinants of B. suis and B. microti in Gerhardt's minimal medium at pH 4.5 and 7.0 for 20 min and 2 h by comparative RNA-Seq-based transcriptome analysis, validated by RT-qPCR. Results yielded a common core response in both species with a total of 150 differentially expressed genes, and acidic pH-dependent genes regulated specifically in each species. The identified core response mechanisms comprise proton neutralization or extrusion from the cytosol, participating in maintaining physiological intracellular pH values. Differential expression of 441 genes revealed species-specific mechanisms in B. microti with rapid physiological adaptation to acid stress, anticipating potential damage to cellular components and critical energy conditions. Acid stress-induced genes encoding cold shock protein CspA, pseudogene in B. suis, and stress protein Dps were associated with survival of B. microti at pH 4.5. B. suis response with 284 specifically regulated genes suggested increased acid stress-mediated protein misfolding or damaging, triggering the set-up of repair strategies countering the consequences rather than the origin of acid stress and leading to subsequent loss of viability. In conclusion, our work supports the hypothesis that increased acid stress resistance of B. microti is based on selective pressure for the maintenance of functionality of critical genes, and on specific differential gene expression, resulting in rapid adaptation.

Emerging diversity and ongoing expansion of the genus Brucella

Remarkable genetic diversity and breadth of host species has been uncovered in the Brucella genus over the past decade, fundamentally changing our concept of what it means to be a Brucella. From ocean fishes and marine mammals, to pond dwelling amphibians, forest foxes, desert rodents, and cave-dwelling bats, Brucella have revealed a variety of previously unknown niches. Classical microbiological techniques have been able to help us classify many of these new strains but at times have limited our ability to see the true relationships among or within species. The closest relatives of Brucella are soil bacteria and the adaptations of Brucella spp. to live intracellularly suggest that the genus has evolved to live in vertebrate hosts. Several recently discovered species appear to have phenotypes that are intermediate between soil bacteria and core Brucella, suggesting that they may represent ancestral traits that were subsequently lost in the traditional species. Remarkably, the broad relationships among Brucella species using a variety of sequence and fragment-based approaches have been upheld when using comparative genomics with whole genomes. Nonetheless, genomes are required for fine-scale resolution of many of the relationships and for understanding the evolutionary history of the genus. We expect that the coming decades will reveal many more hosts and previously unknown diversity in a wide range of environments.

Genital Brucella suis Biovar 2 Infection of Wild Boar (Sus scrofa) Hunted in Tuscany (Italy)

Brucellosis is a zoonosis caused by different Brucella species. Wild boar (Sus scrofa) could be infected by some species and represents an important reservoir, especially for B. suis biovar 2. This study aimed to investigate the prevalence of Brucella spp. by serological and molecular assays in wild boar hunted in Tuscany (Italy) during two hunting seasons. From 287 animals, sera, lymph nodes, livers, spleens, and reproductive system organs were collected. Within sera, 16 (5.74%) were positive to both rose bengal test (RBT) and complement fixation test (CFT), with titres ranging from 1:4 to 1:16 (corresponding to 20 and 80 ICFTU/mL, respectively). Brucella spp. DNA was detected in four lymph nodes (1.40%), five epididymides (1.74%), and one fetus pool (2.22%). All positive PCR samples belonged to Brucella suis biovar 2. The results of this investigation confirmed that wild boar represents a host for B.suis biovar. 2 and plays an important role in the epidemiology of brucellosis in central Italy. Additionally, epididymis localization confirms the possible venereal transmission.

Cell membrane components of Brucella melitensis play important roles in the resistance of low-level rifampicin

Brucella spp. are facultative intracellular pathogens that can persistently colonize host cells and cause the zoonosis- brucellosis. The WHO recommended a treatment for brucellosis that involves a combination of doxycycline, rifampicin, or streptomycin. The aim of this study was to screen rifampicin-resistance related genes by transcriptomic analysis and gene recombination method at low rifampicin concentrations and to predict the major rifampicin- resistance pathways in Brucella spp. The results showed that the MIC value of rifampicin for B. melitensis bv.3 Ether was 0.5 μg / mL. Meanwhile, B. melitensis had an adaptive response to the resistance of low rifampicin in the early stages of growth, while the SNPs changed in the rpoB gene in the late stages of growth when incubated at 37°C with shaking. The transcriptome results of rifampicin induction showed that the functions of significant differentially expressed genes were focused on metabolic process, catalytic activity and membrane and membrane part. The VirB operon, β-resistance genes, ABC transporters, quorum-sensing genes, DNA repair- and replication -related genes were associated with rifampicin resistance when no variations of the in rpoB were detected. Among the VirB operons, VirB7-11 may play a central role in rifampicin resistance. This study provided new insights for screening rifampicin resistance-related genes and also provided basic data for the prevention and control of rifampicin-resistant Brucella isolates.

Brucella spp. are facultative intracellular pathogens that can persistently colonize host cells and cause the zoonosis- brucellosis. The WHO recommended a treatment for brucellosis that involves a combination of doxycycline, rifampicin, or streptomycin. Rifampicin-resistance related genes were screened by transcriptomic analysis and gene recombination method at low rifampicin concentrations and the major rifampicin- resistance pathways in Brucella spp were predicted. The results showed that the VirB operon, β-resistance genes, ABC transporters, quorum-sensing genes, DNA repair- and replication -related genes were associated with rifampicin resistance when no variations of the in rpoB were detected. Among the VirB operons, VirB7-11 may play a central role in rifampicin resistance.

Loci Associated With Antibody Response in Feral Swine (Sus scrofa) Infected With Brucella suis

Feral swine (Sus scrofa) are a destructive invasive species widespread throughout the United States that disrupt ecosystems, damage crops, and carry pathogens of concern for the health of domestic stock and humans including Brucella suis-the causative organism for swine brucellosis. In domestic swine, brucellosis results in reproductive failure due to abortions and infertility. Contact with infected feral swine poses spillover risks to domestic pigs as well as humans, companion animals, wildlife, and other livestock. Genetic factors influence the outcome of infectious diseases; therefore, genome wide association studies (GWAS) of differential immune responses among feral swine can provide an understanding of disease dynamics and inform management to prevent the spillover of brucellosis from feral swine to domestic pigs. We sought to identify loci associated with differential antibody responses among feral swine naturally infected with B. suis using a case-control GWAS. Tissue, serum, and genotype data (68,516 bi-allelic single nucleotide polymorphisms) collected from 47 feral swine were analyzed in this study. The 47 feral swine were culture positive for Brucella spp. Of these 47, 16 were antibody positive (cases) whereas 31 were antibody negative (controls). Single-locus GWAS were performed using efficient mixed-model association eXpedited (EMMAX) methodology with three genetic models: additive, dominant, and recessive. Eight loci associated with seroconversion were identified on chromosome 4, 8, 9, 10, 12, and 18. Subsequent bioinformatic analyses revealed nine putative candidate genes related to immune function, most notably phagocytosis and induction of an inflammatory response. Identified loci and putative candidate genes may play an important role in host immune responses to B. suis infection, characterized by a detectable bacterial presence yet a differential antibody response. Given that antibody tests are used to evaluate brucellosis infection in domestic pigs and for disease surveillance in invasive feral swine, additional studies are needed to fully understand the genetic component of the response to B. suis infection and to more effectively translate estimates of Brucella spp. antibody prevalence among feral swine to disease control management action.

The global epidemiology of Brucella infections in terrestrial wildlife: A meta-analysis

Brucellosis is a widespread zoonotic disease with serious consequences on human and animal health. Brucella infections were reported in many terrestrial wild animals, from subtropical and temperate regions to arctic regions. In many areas, the epidemiology of brucellosis in wildlife is closely associated with the occurrence of the disease in livestock. Some wild species may contribute to the re-introduction of Brucella infections in livestock (spillback), even in officially brucellosis-free (OBF) regions. Through meta-regression analysis, this study draws a global picture of the prevalence of Brucella spp. in terrestrial wild animals, trying to determine most affected subgroups as well as preferential sampling and screening methods. For this purpose, a literature search was carried out among publications published from 1983 to 2019. Different subgroups were compared according to animal species, feeding, gender, age as well as the method used for sampling and for brucellosis diagnostic. To determine heterogeneity of studies, chi-squared test was used and a random-effects model (REM) estimated the pooled prevalence among subgroups. A total of 68 publications, comprising 229 data reports/studies, were selected. The most-reported Brucella species in wildlife was Brucella abortus, and the highest prevalence rate was found in American bison, Bison bison (39.9%) followed by Alpine ibex, Capra ibex (33%). Serology was the most widely applied diagnostic approach (66%), while PCR appeared to be highly sensitive (36.62% of positive results). The gender of animals showed no significant association with the prevalence of brucellosis (p > .05). Blood samples and visceral organs constituted the great majority of specimen used for the detection of Brucella spp., while lymph nodes showed a high prevalence of positive samples (94.6%). The present study provides insight into the global epidemiology and enzootic potential of brucellosis in wild terrestrial animals worldwide, aiming at helping the appropriate authorities to strengthen prevention, surveillance and control strategies.

Whole-genome sequencing of rough Brucella melitensis in China provides insights into its genetic features

Brucella spp. can cause the zoonosis brucellosis, which affects public health and safety and even economic development. B. melitensis has a smooth phenotype, while 28 B. melitensis isolates had a rough phenotype in 2018. In this study, rough phenotype detection and whole genome sequencing methods were used to analyze the genetic features of rough B. melitensis. A drug susceptibility test was also performed. The results showed that the rough B. melitensis strains originated from strains isolated in China rather than from foreign strains. Furthermore, an MS tree showed that 9 complexes to be epidemic in China. For the rough B. melitensis strains, expression of the metabolic function genes varied in the earlier stages of evolution compared to the cellular process and signalling function genes. Expression of some transcriptional regulatory factors also varied in the later stages of evolution, and compared to MFS transporter genes, ABC transporter genes varied in the earlier stages. Moreover, as there was no significant difference in rifampicin, doxycycline and streptomycin susceptibility between the smooth and rough B. melitensis strains, treatment of brucellosis was not affected by strain type. This study provided important information for understanding the genetics and evolution of rough B. melitensis in China.

Research Progress on Brucellosis

Brucellosis is a debilitating febrile illness caused by an intracellular Brucella. The disease is distributed in humans and animals widely, especially in developing countries. Ten species are included in the genus Brucella nowadays; four species of them are pathogenic to humans, which make brucellosis a zoonosis with more than 500,000 new cases reported annually. For human brucellosis, the most pathogenic species is B. melitensis followed by B. suis, while B. abortus is the mildest type of brucellosis. The infection mechanism of Brucella is complicated and mostly relies on its virulence factors. The therapy of the disease contains vaccination and antibiotic. However, there are some defects in currently available vaccines such as the lower protective level and safety. Thus, safe and efficient vaccines for brucellosis are still awaited. The dual therapy of antibacterial is effective in the treatment of brucellosis if a rapid and exact detection method is found.

Establishment and Initial Testing of a Medium-Sized, Surgically Feasible Animal Model for Brucellar Spondylodiscitis: A Preliminary Study

Brucellar spondylodiscitis, the most prevalent and significant osteoarticular presentation of human Brucellosis, is difficult to diagnose and usually yields irreversible neurologic deficits and spinal deformities. However, no animal models of Brucellar spondylodiscitis exist, allowing for preclinical investigations. The present study investigated whether intraosseous injection of attenuated Brucella melitensis vaccine into rabbits' lumbar vertebrae imitates the radiographic and histopathological characteristics of human Brucellar spondylodiscitis. Radiographic and histopathological analyses at 8 weeks postoperatively revealed radiographic changes within vertebral bodies and intervertebral discs, abscesses formation within the paravertebral soft tissue, and typical prominent inflammation response without caseous necrosis, which were largely comparable to human Brucellar spondylodiscitis. Such a medium-sized, surgically feasible rabbit model provides a promising in vivo setting for further preclinical investigation of Brucellar spondylodiscitis.

Development of Molecular Methods for Rapid Differentiation of Mycoplasma gallisepticum Vaccine Strains from Field Isolates

Mycoplasma gallisepticum is among the most economically significant mycoplasmas causing production losses in poultry. Seven melt-curve and agarose gel-based mismatch amplification mutation assays (MAMAs) and one PCR are provided in the present study to distinguish the M. gallisepticum vaccine strains and field isolates based on mutations in the crmA, gapA, lpd, plpA, potC, glpK, and hlp2 genes. A total of 239 samples (M. gallisepticum vaccine and type strains, pure cultures, and clinical samples) originating from 16 countries and from at least eight avian species were submitted to the presented assays for validation or in blind tests. A comparison of the data from 126 samples (including sequences available at GenBank) examined by the developed assays and a recently developed multilocus sequence typing assay showed congruent typing results. The sensitivity of the melt-MAMA assays varied between 10¹ and 10⁴ M. gallisepticum template copies/reaction, while that of the agarose-MAMAs ranged from 10³ to 10⁵ template copies/reaction, and no cross-reactions occurred with other Mycoplasma species colonizing birds. The presented assays are also suitable for discriminating multiple strains in a single sample. The developed assays enable the differentiation of live vaccine strains by targeting two or three markers/vaccine strain; however, considering the high variability of the species, the combined use of all assays is recommended. The suggested combination provides a reliable tool for routine diagnostics due to the sensitivity and specificity of the assays, and they can be performed directly on clinical samples and in laboratories with basic PCR equipment.

Characterization of Carbapenemase-Producing Klebsiella oxytoca in Spain, 2016-2017

There is little information about carbapenemase-producing (CP) Klebsiella oxytoca, an important nosocomial pathogen. We characterized CP K. oxytoca isolates collected from different Spanish hospitals between January 2016 and October 2017. During the study period, 139 nonduplicate CP K. oxytoca isolates were identified; of these, 80 were studied in detail. Carbapenemase and extended-spectrum β-lactamase genes were identified by PCR and sequencing. Genetic relatedness was studied by pulsed-field gel electrophoresis (PFGE). Whole-genome sequencing (WGS), carried out on 12 representative isolates, was used to identify the resistome, to elucidate the phylogeny, and to determine the plasmids harboring carbapenemase genes. Forty-eight (60%) isolates produced VIM-1, 30 (37.5%) produced OXA-48, 3 (3.7%) produced KPC-2, 2 (2.5%) produced KPC-3, and 1 (1.2%) produced NDM-1; 4 isolates coproduced two carbapenemases. By PFGE, 69 patterns were obtained from the 80 CP K. oxytoca isolates, and four well-defined clusters were detected: cluster 1 consisted of 11 OXA-48-producing isolates, and the other three clusters included VIM-1-producing isolates (5, 3, and 3 isolates, respectively). In the 12 sequenced isolates, the average number of acquired resistance genes was significantly higher in VIM-1-producing isolates (10.8) than in OXA-48-producing isolates (2.3). All 12 isolates had chromosomally encoded genes of the bla _OXY-2 genotype, and by multilocus sequence typing, most belonged to sequence type 2 (ST2). Carbapenemase genes were carried by IncL, IncHI2, IncFII, IncN, IncC, and IncP6 plasmid types. The emergence of CP K. oxytoca was principally due to the spread of VIM-1- and OXA-48-producing isolates in which VIM-1- and OXA-48 were carried by IncL, IncHI2, IncFII, and IncN plasmids. ST2 and the genotype bla _OXY-2 predominated among the 12 sequenced isolates.

Phenotypic and Molecular Characterization of Brucella microti-Like Bacteria From a Domestic Marsh Frog (Pelophylax ridibundus)

Several Brucella isolates have been described in wild-caught and "exotic" amphibians from various continents and identified as B. inopinata-like strains. On the basis of epidemiological investigations conducted in June 2017 in France in a farm producing domestic frogs (Pelophylax ridibundus) for human consumption of frog's legs, potentially pathogenic bacteria were isolated from adults showing lesions (joint and subcutaneous abscesses). The bacteria were initially misidentified as Ochrobactrum anthropi using a commercial identification system, prior to being identified as Brucella spp. by MALDI-TOF assay. Classical phenotypic identification confirmed the Brucella genus, but did not make it possible to conclude unequivocally on species determination. Conventional and innovative bacteriological and molecular methods concluded that the investigated strain was very close to B. microti species, and not B. inopinata-like strains, as expected. The methods included growth kinetic, antimicrobial susceptibility testing, RT-PCR, Bruce-Ladder, Suis-Ladder, RFLP-PCR, AMOS-ERY, MLVA-16, the ectoine system, 16S rRNA and recA sequence analyses, the LPS pattern, in silico MLST-21, comparative whole-genome analyses (including average nucleotide identity ANI and whole-genome SNP analysis) and HRM-PCR assays. Minor polyphasic discrepancies, especially phage lysis and A-dominant agglutination patterns, as well as, small molecular divergences suggest the investigated strain should be considered a B. microti-like strain, raising concerns about its environmental persistence and unknown animal pathogenic and zoonotic potential as for other B. microti strains described to date.

Genotyping Mycoplasma synoviae: Development of a multi-locus variable number of tandem-repeats analysis and comparison with current molecular typing methods

Control of one of the most important avian mycoplasmas, Mycoplasma synoviae, and tracing the spread of the infection can be challenging as the pathogen is transmissible by both horizontal and vertical routes, and it can be disseminated through long distances via the hatching eggs, day-old chicks or pullets during intensive international trade. Genetic information provided by molecular typing methods support control programmes and epizootiologic studies. The aims of the present study were to develop a multi-locus variable number of tandem-repeats analysis (MLVA) method for the typing of M. synoviae isolates and to evaluate the currently used molecular typing methods which are applicable directly on clinical samples. Tandem repeat (TR) regions were selected from the whole genome sequence of the M. synoviae type strain (WVU1853) to characterise the genetic diversity of 86 M. synoviae strains originating from 15 countries. The strains were also submitted to multi-locus sequence typing (MLST) assays, vlhA gene sequence analysis and to assays designed to differentiate live vaccine strains from field strains. The developed MLVA involves the examination of seven TR regions and provides similar genetic resolution as the tested MLST assays by identifying 35 genotypes among the tested strains. Differentiation of the live vaccine strains from field strains was also successful with the developed assay. The provided MLVA method proved to be a highly discriminative, rapid and cost-effective alternative typing technique for the genetic characterisation of M. synoviae and it is also suitable for the complementation of live vaccine strain differentiating assays in ambiguous cases.

RECENT CHANGES IN INFECTIOUS DISEASES IN EUROPEAN WILDLIFE

Many infectious diseases originating from, or carried by, wildlife affect wildlife conservation and biodiversity, livestock health, or human health. We provide an update on changes in the epidemiology of 25 selected infectious, wildlife-related diseases in Europe (from 2010-16) that had an impact, or may have a future impact, on the health of wildlife, livestock, and humans. These pathogens were selected based on their: 1) identification in recent Europe-wide projects as important surveillance targets, 2) inclusion in European Union legislation as pathogens requiring obligatory surveillance, 3) presence in recent literature on wildlife-related diseases in Europe since 2010, 4) inclusion in key pathogen lists released by the Office International des Epizooties, 5) identification in conference presentations and informal discussions on a group email list by a European network of wildlife disease scientists from the European Wildlife Disease Association, or 6) identification as pathogens with changes in their epidemiology during 2010-16. The wildlife pathogens or diseases included in this review are: avian influenza virus, seal influenza virus, lagoviruses, rabies virus, bat lyssaviruses, filoviruses, canine distemper virus, morbilliviruses in aquatic mammals, bluetongue virus, West Nile virus, hantaviruses, Schmallenberg virus, Crimean-Congo hemorrhagic fever virus, African swine fever virus, amphibian ranavirus, hepatitis E virus, bovine tuberculosis ( Mycobacterium bovis), tularemia ( Francisella tularensis), brucellosis ( Brucella spp.), salmonellosis ( Salmonella spp.), Coxiella burnetii, chytridiomycosis, Echinococcus multilocularis, Leishmania infantum, and chronic wasting disease. Further work is needed to identify all of the key drivers of disease change and emergence, as they appear to be influencing the incidence and spread of these pathogens in Europe. We present a summary of these recent changes during 2010-16 to discuss possible commonalities and drivers of disease change and to identify directions for future work on wildlife-related diseases in Europe. Many of the pathogens are entering Europe from other continents while others are expanding their ranges inside and beyond Europe. Surveillance for these wildlife-related diseases at a continental scale is therefore important for planet-wide assessment, awareness of, and preparedness for the risks they may pose to wildlife, domestic animal, and human health.

Genotypic Expansion Within the Population Structure of Classical Brucella Species Revealed by MLVA16 Typing of 1404 Brucella Isolates From Different Animal and Geographic Origins, 1974-2006

Previous studies have shown the usefulness of MLVA16 as a rapid molecular identification and classification method for Brucella species and biovars including recently described novel Brucella species from wildlife. Most studies were conducted on a limited number of strains from limited geographic/host origins. The objective of this study was to assess genetic diversity of Brucella spp. by MLVA16 on a larger scale. Thus, 1404 animal or human isolates collected from all parts of the world over a period of 32 years (1974-2006) were investigated. Selection of the 1404 strains was done among the approximately 4000 strains collection of the BCCN (Brucella Culture Collection Nouzilly), based on classical biotyping and on the animal/human/geographic origin over the time period considered. MLVA16 was performed on extracted DNAs using high throughput capillary electrophoresis. The 16 loci were amplified in four multiplex PCR reactions. This large scale study firstly confirmed the accuracy of MLVA16 typing for Brucella species and biovar identification and its congruence with the recently described Extended Multilocus Sequence Analysis. In addition, it allowed identifying novel MLVA11 (based upon 11 slowly evolving VNTRs) genotypes representing an increase of 15% relative to the previously known Brucella MLVA11 genotypes. Cluster analysis showed that among the MLVA16 genotypes some were genetically more distant from the major classical clades. For example new major clusters of B. abortus biovar 3 isolated from cattle in Sub-Saharan Africa were identified. For other classical species and biovars this study indicated also genotypic expansion within the population structure of classical Brucella species. MLVA proves to be a powerful tool to rapidly assess genetic diversity of bacterial populations on a large scale, as here on a large collection of strains of the genomically homogeneous genus Brucella. The highly discriminatory power of MLVA appears of particular interest as a first step for selection of Brucella strains for whole-genome sequencing. The MLVA data of this study were added to the public Brucella MLVA database at http://microbesgenotyping.i2bc.paris-saclay.fr. Current version Brucella_4_3 comprises typing data from more than 5000 strains including in silico data analysis of public whole genome sequence datasets.

The Glutaminase-Dependent System Confers Extreme Acid Resistance to New Species and Atypical Strains of Brucella

Neutralophilic bacteria have developed specific mechanisms to cope with the acid stress encountered in environments such as soil, fermented foods, and host compartments. In Escherichia coli, the glutamate decarboxylase (Gad)-dependent system is extremely efficient: it requires the concerted action of glutamate decarboxylase (GadA/GadB) and of the glutamate (Glu)/γ-aminobutyrate antiporter, GadC. Notably, this system is operative also in new strains/species of Brucella, among which Brucella microti, but not in the “classical” species, with the exception of marine mammals strains. Recently, the glutaminase-dependent system (named AR2_Q), relying on the deamination of glutamine (Gln) into Glu and on GadC activity, was described in E. coli. In Brucella genomes, a putative glutaminase (glsA)-coding gene is located downstream of the gadBC genes. We found that in B. microti these genes are expressed as a polycistronic transcript. Moreover, using a panel of Brucella genus-representative strains, we show that the AR2_Q system protects from extreme acid stress (pH ≤2.5), in the sole presence of Gln, only the Brucella species/strains predicted to have functional glsA and gadC. Indeed, mutagenesis approaches confirmed the involvement of glsA and gadC of B. microti in AR2_Q and that the acid-sensitive phenotype of B. abortus can be ascribed to a Ser248Leu substitution in GlsA, leading to loss of glutaminase activity. Furthermore, we found that the gene BMI_II339, of unknown function and downstream of the gadBC–glsA operon, positively affects Gad- and GlsA-dependent AR. Thus, we identified novel determinants that allow newly discovered and marine mammals Brucella strains to be better adapted to face hostile acidic environments. As for significance, this work may contribute to the understanding of the host preferences of Brucella species and opens the way to alternative diagnostic targets in epidemiological surveillance of brucellosis.

Complete Genome Sequences of Four Brucella Strains Isolated from China

Brucella spp. are facultative intracellular pathogens that cause a contagious zoonotic disease. Twelve different species are currently identified. This study presents the complete genome sequences of four Brucella strains. These complete genomes were annotated and the contents compared to those of other strains isolated from China.

Mutations Associated with Decreased Susceptibility to Seven Antimicrobial Families in Field and Laboratory-Derived Mycoplasma bovis Strains

The molecular mechanisms of resistance to fluoroquinolones, tetracyclines, an aminocyclitol, macrolides, a lincosamide, a phenicol, and pleuromutilins were investigated in Mycoplasma bovis For the identification of mutations responsible for the high MICs of certain antibiotics, whole-genome sequencing of 35 M. bovis field isolates and 36 laboratory-derived antibiotic-resistant mutants was performed. In vitro resistant mutants were selected by serial passages of M. bovis in broth medium containing subinhibitory concentrations of the antibiotics. Mutations associated with high fluoroquinolones MICs were found at positions 244 to 260 and at positions 232 to 250 (according to Escherichia coli numbering) of the quinolone resistance-determining regions of the gyrA and parC genes, respectively. Alterations related to elevated tetracycline MICs were described at positions 962 to 967, 1058, 1195, 1196, and 1199 of genes encoding the 16S rRNA and forming the primary tetracycline binding site. Single transversion at position 1192 of the rrs1 gene resulted in a spectinomycin MIC of 256 μg/ml. Mutations responsible for high macrolide, lincomycin, florfenicol, and pleuromutilin antibiotic MICs were identified in genes encoding 23S rRNA. Understanding antibiotic resistance mechanisms is an important tool for future developments of genetic-based diagnostic assays for the rapid detection of resistant M. bovis strains.

Swine brucellosis: current perspectives

Brucella suis is a significant zoonotic species that is present in domestic livestock and wildlife in many countries worldwide. Transmission from animal reservoirs is the source of human infection as human-to-human transmission is very rare. Although swine brucellosis causes economic losses in domestic livestock, preventing human infection is the primary reason for its emphasis in disease control programs. Although disease prevalence varies worldwide, in areas outside of Europe, swine brucellosis is predominantly caused by B. suis biovars 1 and 3. In Europe, swine are predominantly infected with biovar 2 which is much less pathogenic in humans. In many areas worldwide, feral or wild populations of swine are important reservoir hosts. Like other Brucella spp. in their natural host, B. suis has developed mechanisms to survive in an intracellular environment and evade immune detection. Limitations in sensitivity and specificity of current diagnostics require use at a herd level, rather for individual animals. There is currently no commercial vaccine approved for preventing brucellosis in swine. Although not feasible in all situations, whole-herd depopulation is the most effective regulatory mechanism to control swine brucellosis.