Detection of caprine paratuberculosis (Johne's disease) in pre- and post-vaccinated herds: morphological diagnosis, lesion grading, and bacterial identification.

Samples from the mesenteric lymph nodes (MS LNs) and ileocecal valves (ICV) of 105 goats, comprising 61 non-vaccinated and 44 vaccinated against Mycobacterium avium subspecies paratuberculosis (MAP), were collected at slaughter from a farm with a confirmed history of paratuberculosis (PTB). These goats had subclinical infections. PTB-compatible lesions in the MS LNs, ICV lamina propria (LP), and Peyer's patches (PPs) were graded separately. Furthermore, the load of acid-fast bacilli was quantified using Ziehl-Neelsen staining (ZN), MAP antigens by immunohistochemistry (IHC), and MAP DNA by PCR targeting the IS900 sequence. Gross PTB-compatible lesions were found in 39% of the goats, with 31.72% vaccinated (V) and 68.29% non-vaccinated (nV). Histopathological lesions induced MAP were observed in 58% of the animals, with 36.07% vaccinated and 63.93% non-vaccinated. The inclusion of histopathology as a diagnostic tool led to a 28% increase in diagnosed cases in MS LNs and 86.05% in ICV. Grade IV granulomas with central mineralization and necrosis were the most common lesions in MS LNs. In the ICV, mild granulomatous enteritis with multifocal foci of epithelioid macrophages was predominant, occurring more frequently in the PPs than in the LP. Furthermore, statistical differences in the presence of histopathological lesions between vaccinated and non-vaccinated goats were noted in MS LNs, ICV LPs, and ICV PPs. Non-vaccinated animals showed higher positivity rates in ZN, IHC, and PCR tests, underscoring the benefits of anti-MAP vaccination in reducing PTB lesions and bacterial load in target organs. Our findings emphasize the necessity of integrating gross and histopathological assessments with various laboratory techniques for accurate morphological and etiological diagnosis of PTB in both vaccinated and non-vaccinated goats with subclinical disease. However, further studies are required to refine sampling protocols for subclinical PTB in goats to enhance the consistency of diagnostic tools.

Neuropathological lesions in intravenous BCG-stimulated K18-hACE2 mice challenged with SARS-CoV-2.

In the wake of the COVID-19 pandemic caused by SARS-CoV-2, questions emerged about the potential effects of Bacillus Calmette-Guérin (BCG) vaccine on the immune response to SARS-CoV-2 infection, including the neurodegenerative diseases it may contribute to. To explore this, an experimental study was carried out in BCG-stimulated and non-stimulated k18-hACE2 mice challenged with SARS-CoV-2. Viral loads in tissues determined by RT-qPCR, histopathology in brain and lungs, immunohistochemical study in brain (IHC) as well as mortality rates, clinical signs and plasma inflammatory and coagulation biomarkers were assessed. Our results showed BCG-SARS-CoV-2 challenged mice presented higher viral loads in the brain and an increased frequency of neuroinvasion, with the greatest differences observed between groups at 3-4 days post-infection (dpi). Histopathological examination showed a higher severity of brain lesions in BCG-SARS-CoV-2 challenged mice, mainly consisting of neuroinflammation, increased glial cell population and neuronal degeneration, from 5 dpi onwards. This group also presented higher interstitial pneumonia and vascular thrombosis in lungs (3-4 dpi), BCG-SARS-CoV-2 mice showed higher values for TNF-α and D-dimer values, while iNOS values were higher in SARS-CoV-2 mice at 3-4 dpi. Results presented in this study indicate that BCG stimulation could have intensified the inflammatory and neurodegenerative lesions promoting virus neuroinvasion and dissemination in this experimental model. Although k18-hACE2 mice show higher hACE2 expression and neurodissemination, this study suggests that, although the benefits of BCG on enhancing heterologous protection against pathogens and tumour cells have been broadly demonstrated, potential adverse outcomes due to the non-specific effects of BCG should be considered.

Non-invasive surveillance of shared pathogens in the Eurasian brown bear (Ursus arctos) human interface.

Multi-host communities are perfect scenarios for the emergence and spread of pathogens, threatening the recovery of endangered, isolated, or inbred populations, such as the brown bear (Ursus arctos) in northwestern Spain. The population recovery in recent years has forced bears to occupy highly anthropized areas, increasing their interaction with human and domestic animals, with potential consequences for global health. During 2022-2023 a survey of parasites, bacteria and viruses shared between wildlife, domestic animals and humans was performed in this population using non-invasive surveillance, i.e., bear fecal samples (n = 73) and sponge-based sampling of trees (n = 42; 14 rubbed trees and 28 control trees). Pathogen detection rates were defined as the percentage of qPCR or culture-positive samples. Generalized linear models were fitted to assess their relationship with environmental variables including dispersion of the human population, and percentage of agricultural and periurban habitats in a 6 km-buffer around each sample. Canine Adenovirus type 1 (45.2%), Giardia spp. (15.1%), Salmonella spp. (12.3%), and extended-spectrum-beta-lactamases (ESBL) Escherichia coli (1.4%) were identified in fecal samples. In contrast, only five sponges from three rubbed and two control trees resulted positive to E. coli (14.3%). The results suggest that several pathogens are common in the Cantabrian brown bear population and that anthropization of the territory modulates their prevalence and richness. The effective design of management programs for bear conservation will require a one-health approach, in which genetic analysis of non-invasive samples can be key tools for the sanitary surveillance at the wildlife-livestock-human interface.

Time, temperature and media: the three keys to improve the recovery of Campylobacter fetus subsp. venerealis from preputial bull samples.

The isolation of Campylobacter fetus subsp. venerealis (Cfv) from clinical samples is the gold standard for confirming cases of bovine genital campylobacteriosis, an important cause of infertility in cattle and a potential public health concern. Furthermore, isolation is also necessary for the development of autologous vaccines, characterization of strains for antimicrobial susceptibility patterns, etc. Nevertheless, the sensitivity of culture methods is usually low, and there is no standardized protocol to maximize the recovery of Cfv from clinical samples. The aim of the current study is to design a protocol for the culture of Cfv from preputial samples by evaluating the combination of different transport, enrichment and culture media considering the impact of certain factors (time between collection and enrichment, temperature, and use of filters). The use of modified Lander's transport medium and storing the sample for 24 h at 21 ± 2 °C led to the highest recovery of Cfv CFUs. In contrast, the storage of the samples during 24-48 h in PBS and Thomann rarely allowed the recovery of Cfv regardless of the temperature. The enrichment medium yielding the best results was Preston (significantly higher recovery than Brucella medium), while Cfv could not be isolated with Bolton. Regarding our diagnostic assay (using Lander as transport medium and Preston as enrichment medium), the best protocol in terms of maximizing Cfv recovery as well as limiting contaminations is to culture the samples in i) solid media Preston or Skirrow, and ii) using 0.65 µm filters and incubating plates at 37 °C in microaerophilic conditions.

Active surveillance of antimicrobial resistance in companion animals: A pilot study in a Spanish Veterinary Teaching Hospital.

The role of small animal veterinary hospitals in the onset and dissemination of antimicrobial-resistant organisms (AMROs) is still not clear, and the implementation of an internal surveillance systems is a cost-effective tool to better understand their impact. The aim of this study was to describe a pilot program of active surveillance in a Spanish Veterinary Teaching Hospital, developed to estimate the detection frequency of AMROs in the commensal flora of patients and in the environment. Surveillance was focused on Methicillin-resistant Staphylococci (MRS), third generation cephalosporins resistant gram-negative bacteria (3GCR-GNB), and carbapenems-resistant gram-negative bacteria (CR-GNB). Oral and perirectal swabs were collected in the same dogs and cats hospitalized > 48 h, at their admission and before their discharge. Out of 50 patients sampled, 24% (12/50) were carriers at admission of at least one of the three investigated AMROs. Twenty-eight percent of patients (14/50) acquired at least one AMRO during the hospital stay. MRS detection frequency at admission was 12% (6/50), while acquisition was 6% (3/50). 3GCR-GNB detection frequency was 14% at admission (7/50) and acquisition 22% (11/50), while CR-GNB detection frequency was 2% at admission (1/50) and acquisition 2% (1/50). Environmental surveillance (98 samples) showed a total detection frequency of 22.4% for MRS (22/98), 2% for 3GCR-GNB and CR-GNB (2/98). Clinical staff' shoe soles showed high detection frequency for MRS (50%). 3GCR Escherichia coli was the most isolated species in patients (n = 17). The results show how active surveillance can be used as a tool to assess the impact of AMROs in veterinary hospitals to subsequently build up tailored control plans based on specific issues.

New insights into the pathogenesis and transmission of Brucella pinnipedialis: systemic infection in two bottlenose dolphins (Tursiops truncatus).

IMPORTANCE: Brucella spp. are zoonotic pathogens that can affect both terrestrial and marine mammals. Brucella ceti has been identified in various cetacean species, but only one sequence type (ST27) has been reported in humans. However, it is important to conduct surveillance studies to better understand the impact of marine Brucella species on marine mammals, a typically understudied host group. Here, we describe a systemic infection by two related strains of Brucella pinnipedialis (ST25) in a couple of live-stranded bottlenose dolphins, with more severe lesions in the younger animal. Furthermore, B. pinnipedialis was first detected in milk from a female cetacean that stranded with its offspring. Our study reveals novel insights into the epidemiology and pathological consequences of B. pinnipedialis infections in cetaceans, emphasizing the crucial importance of ongoing surveillance and accurate diagnosis to understand the impact of this pathogen on marine mammal populations.

Immunopathology of early and advanced epididymis lesions caused by Brucella ovis in rams.

Ovine brucellosis is an infectious disease that causes alterations in the reproductive tract in ram and abortion in ewes. Their negative economic impact in ovine production warrants a thorough understanding the interactions between B. ovis and the host. Here, epididymis lesions of rams infected by B. ovis were histopathologically staged into early and advanced. Expression by immunohistochemistry of Brucella antigens, inflammatory cell markers (CD3, CD79αcy) and cytokines (IFN-γ, TNF-α, TGF-ß1) was assessed in both stages. Early lesions were characterized by epithelial changes, interstitial inflammation, and mild fibrosis; whereas advanced lesions displayed caseous granulomas containing numerous macrophages, multinucleated giant cells, lymphocytes, and plasma cells. Expression of Brucella antigens were observed in both stages. The cellular response in B. ovis lesions were predominantly of T-cells (CD3+) whereas low numbers of B-cells and plasma cells (CD79αcy+) were present in both early and advanced lesions. IFN-γ was expressed by lymphocytes in early lesions suggesting that the adaptive immune response against B. ovis is initiated by Th1 cells, this response was also preserved in advanced stages. Expression of TNF-α was observed in neutrophils of epithelial microabscesses and intraepithelial T-cells of early lesions suggesting a promotion of neutrophil phagocytosis triggered by TNF-α. On the other hand, advanced lesions showed a reduction of TNF-α expression which may permit B. ovis persistence in granulomas. Lastly, TGF-ß1 expression (fibroblast, macrophages and less in lymphocytes) were increased with time, suggesting that B. ovis promotes TGF-ß1 secretion promoting chronicity of the lesions.

First detection of Flavobacterium psychrophilum in juvenile Siberian sturgeons (Acipenser baerii) and description of the pathological findings.

Flavobacterium psychrophilum affects many cultured fish species and is considered one of the most important bacterial pathogens causing substantial economic losses in salmonid aquaculture worldwide. Here, F. psychrophilum was identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nested PCR as the aetiological agent causing mortality in diseased juvenile Siberian sturgeons (Acipenser baerii) reared on a freshwater fish farm. Diseased sturgeons were lethargic and displayed dark skin pigmentation, increased mucus production and the presence of skin ulcerations and haemorrhages specially on the ventral side and the base of fins. The histological examination of fish revealed proliferative branchitis, ulcerative and necrotizing dermatitis and myositis, lymphoid tissue atrophy, liver and kidney degeneration and thrombosis. To the best of our knowledge, this is the first report describing the infection of Siberian sturgeons by F. psychrophilum. The detection of F. psychrophilum in diseased Siberian sturgeons and the description of the pathological findings observed during the outbreak may contribute to a better understanding of the bacterium pathogenicity and the range of fish species susceptible to infection.

A useful tool for the safe diagnosis and control of the two main pandemics of the XXI century: COVID-19 and African Swine Fever disease.

The COVID-19 pandemic and the disease triggered by the African Swine Fever virus are currently two of the main problems regarding public and animal health, respectively. Although vaccination seems to be the ideal tool for controlling these diseases, it has several limitations. Therefore, early detection of the pathogen is critical in order to apply preventive and control measures. Real-time PCR is the main technique used for the detection of both viruses, which requires previous processing of the infectious material. If the potentially infected sample is inactivated at the time of sampling, the diagnosis will be accelerated, impacting positively on the diagnosis and control of the disease. Here, we evaluated the inactivation and preservation properties of a new surfactant liquid for non-invasive and environmental sampling of both viruses. Our results demonstrated that the surfactant liquid effectively inactivates SARS-CoV-2 and African Swine Fever virus in only five minutes, and allows for the preservation of the genetic material for long periods even at high temperatures such as 37°C. Hence, this methodology is a safe and useful tool for recovering SARS-CoV-2 and African Swine Fever virus RNA/DNA from different surfaces and skins, which has significant applied relevance in the surveillance of both diseases.

Histopathologic and immunohistochemical findings in the placentas and fetuses of domestic swine naturally infected with Brucella suis biovar 2.

Porcine brucellosis, which is caused by Brucella suis biovar (bv) 2, is a re-emerging disease that causes reproductive problems in pigs in Europe. The pathogenesis and lesions of B. suis intrauterine infection are poorly characterized; characterization could facilitate the diagnosis and investigation of porcine brucellosis. We collected samples of placentas and fetuses for histologic and microbiologic studies during an outbreak of abortions on a pig-breeding farm in Spain. Brucella was cultured from the vaginal swabs obtained from sows that had aborted, some placentas, and fetal tissues (spleen, liver, lung, gastric content); molecular testing confirmed B. suis bv 2 infection. Histologically, there was necrotizing and hemorrhagic placentitis; suppurative hepatitis; lymphoid depletion and sinusoidal histiocytosis in the spleen, lymph nodes, and thymus; and bronchointerstitial pneumonia. Hemorrhages were observed in the umbilical cord, heart, kidneys, and brain. We detected Brucella by immunohistochemistry (IHC) in all of the placentas and fetal organs studied, specifically in the trophoblasts of the chorionic epithelium, in the cytoplasm of macrophages in the chorionic stroma, and extracellularly in necrotic debris. Furthermore, we assessed the lymphocyte population in the placentas through the use of IHC (anti-CD3, anti-Pax5 antibodies), revealing that the lymphocytic response was composed of T cells but not B cells.

What about the bull? A systematic review about the role of males in bovine infectious infertility within cattle herds.

Numerous pathogens affect cow fertility. Nevertheless, little information has been published about microorganisms associated with cattle infertility focusing on bulls. The present review offers a current analysis and highlights potential key aspects on the relevance of bulls in the emergence of infertility problems of infectious origin within herds that are still not completely determined. The present systematic review was conducted using the PubMed, Web of Science, and Scopus databases on December 9, 2022. In total, 2,224 bibliographic records were reviewed and, according to strict inclusion criteria, 38 articles were selected from 1966 to 2022, from which we ranked more than 27 different microorganisms (fungi were not identified). The most cited pathogens were BoHV (described by 26.3% of the papers), Campylobacter fetus (23.7%), Tritrichomonas foetus (18.4%), and BVDV, Ureaplasma spp., and Mycoplasma spp. (10.5% each). Despite the general trend towards an increasing number of publications about bull-infertility problems, a number of pathogens potentially transmitted through both natural breeding and seminal doses given to females and associated with infertility within herds were not ranked in the study (e.g., Chlamydia spp.). This work highlights i) the need to clearly establish the role of certain microorganisms not traditionally associated with reproductive problems in bull infertility (e.g., Staphylococcus spp. or BoHV-4) and ii) the need to perform additional studies on breeding bulls to clarify their role in infertility problems within herds. This would allow monitoring for pathogens that have gone unnoticed and those that are fastidious to diagnose and/or potentially transmitted to females.

First report and molecular characterization of cases of natural Taylorella asinigenitalis infection in three donkey breeds in Spain.

Taylorella asinigenitalis is a non-pathogenic bacteria isolated from the genital tract of donkeys but also a cause of metritis and vaginal discharge in mares. It is closely related to Taylorella equigenitalis, the cause of Contagious Equine Metritis (CEM) in horses, and has been present in different countries in Europe since 1995. Up to date, there are no studies on the prevalence of T. asinigenitalis in the equine or asinine populations in Spain; this is the first report of the presence of T. asinigenitalis in donkeys (Equus asinus) from different breeds in three regions of Spain. A total of 106 healthy animals of three different Spanish donkey breeds: Andaluza (26), Majorera (12) and Zamorano-Leonés (68) were sampled between June and July 2017 and a real-time PCR was used to detect T. asinigenitalis in all samples. A total of 39/221 (17,65 %) samples from 22/106 (20,75 %) animals yielded a positive result and were further characterized by MLST; an allelic profile and Sequence Type (ST) could be assigned to 11 of the 39 positive samples, resulting in four novel STs and no clonal complexes within the PubMLST database. There were statistically significant differences in the percentage of positive animals by breed and sex, and also in the variability of STs between farms. Breeding management would have an influence on the percentage of positives in a farm; artificial insemination and separating jacks from jennies should be implemented. Further studies to detect and characterize T. asinigenitalis in donkeys and horses from Spain would be required to obtain a broader epidemiological picture in this country.

Effect of heat-inactivated Mycobacterium avium subspecies paratuberculosis (MAP) vaccine on the lesions and immunopathology developed in target tissues of naturally MAP-infected goats.

Paratuberculosis (PTB) is a disease caused by Mycobacterium avium subspecies paratuberculosis (MAP), which affects a broad range of hosts, including domestic and wild animals. PTB is a chronic granulomatous enteritis and lymphadenitis that compromises animal welfare and causes economic losses. The objective of this study was to evaluate the effect of a commercial heat-inactivated MAP vaccine on lesions and immunopathology developed in the target tissues of goats naturally infected with MAP. Lesions compatible with PTB in the intestine and regional lymph nodes (LNs), as well as local immune response to MAP, were evaluated and compared in Gudair®-vaccinated (n = 14) and unvaccinated (n = 11) goats from a MAP-infected farm. The percentage of animals with multifocal granulomatous lesions in the jejunal (p = 0.05) and ileocecal (p = 0.02) LNs was higher in unvaccinated animals, while a lesion score reduction of 50% was found in the LNs of vaccinated animals. Unvaccinated animals showed increased numbers and wider distribution of macrophages (MΦs, CD68 +) in histiocytic infiltrate (p = 0.0003), associated with increased numbers of mycobacteria. Increased inducible nitric oxide synthase (iNOS) expression was also reported in these animals, while M2 MΦs (CD163 +) were scarce in both groups. Vaccinated animals showed an increase in CD3 + lymphocytes, although differences in interferon gamma (IFNγ) were negligible. These results support the hypothesis that heat-inactivated MAP vaccination could reduce the severity of PTB lesions and mycobacterial load in target tissues in vaccinated adult goats.

The Omicron (B.1.1.529) SARS-CoV-2 variant of concern also affects companion animals.

The emergence of the Omicron variant (B.1. 1.529) has brought with it an increase in the incidence of SARS-CoV-2 disease. However, there is hardly any data on its incidence in companion animals. We have detected the presence of this new variant in domestic animals (dogs and cats) living with infected owners in Spain. None of the RT-qPCR positive animals (10.13%) presented any clinical signs and the viral loads detected were low. In addition, the shedding of viral RNA lasted a short period of time in the positive animals. Infection with this variant of concern (VOC) was confirmed by RT-qPCR and sequencing. These outcomes suggest a lower virulence of this variant in infected cats and dogs. They also demonstrate the transmission from infected humans to domestic animals and highlight the importance of active surveillance as well as genomic research to detect the presence of VOCs or mutations associated with animal hosts.

Environment and Offspring Surveillance in Porcine Brucellosis.

Porcine brucellosis, caused by Brucella suis (B. suis), is a notifiable disease causing significant economic losses in production systems. Most infected pigs may act as carriers and shed B. suis even if asymptomatic. This can contribute to environmental persistence, thus hindering control efforts. Here, the environment and the offspring were investigated during and after a B. suis outbreak at a sow breeding farm. The diagnosis of B. suis in sows (n = 1,140) was performed by culture and polymerase chain reaction (PCR) from vaginal swabs, indirect enzyme-linked immunosorbent assay (I-ELISA) from sera, and brucellin skin test (BST). B. suis diagnosis in post-weaning pigs (n = 899) was performed by I-ELISA in sera and BST. The environmental surveillance programme was implemented by placing gauze sponges (n = 175) pre-hydrated in a surfactant and inactivating liquid for Brucella DNA detection by PCR in different farm areas. Our results showed that the offspring of infected sows reacted to in vivo techniques for B. suis. Furthermore, the offspring born during the outbreak displayed higher seropositivity (I-ELISA) and reactivity (BST) than those pigs born after. Brucella DNA was detected in pregnant sow areas, boxes, boots, and post-weaning pig areas. In addition, Brucella DNA environmental detection was higher during the B. suis outbreak than the post B. suis outbreak. The environmental approach has proven to be a simple, practical, valuable, and safe method to detect and monitor B. suis. These results suggest a role of the environment and the offspring that should be considered in porcine brucellosis surveillance and control programmes.

Exploiting 16S rRNA-based metagenomics to reveal neglected microorganisms associated with infertility in breeding bulls in Spanish extensive herds.

Bovine infectious infertility represents a problem due to the high impact on animal production and, in many cases, in public health. A lack of information on the characteristics of the bacterial population of the bovine reproductive system can hamper a comprehensive understanding of reproductive pathologies and the role that the microbiome could play. A metagenomic study based on the V3-V4 hypervariable region of the bacterial 16S rRNA gene was performed in 1029 preputial samples from bulls raised in an extensive regimen in Spain (944 from herds with low fertility rates -case group-, and 85 samples from reproductively healthy herds -control group-). The most representative phyla as well as the most 10 abundant bacterial families and their abundance did not show significant differences in both case and control groups. Similarly, the (alpha and beta) diversity of the bacterial populations was similar in both type of herds: the Shannon and Simpson indices show a high diversity of species, while the Bray-Curtis dissimilarity index did not show relevant differences in the bacterial communities. A deeper analysis of the operational taxonomic units showed the presence of one genera, Mycoplasma spp. significantly associated with fertility problems. Our study highlights the promising potential that the application of sequencing techniques (e.g. 16S rRNA-based metagenomics) possesses in examining bovine infertility, as they are able to reveal different pathogens that could go unnoticed using diagnostic approaches for only the main known pathogens.

First Detection of SARS-CoV-2 B.1.617.2 (Delta) Variant of Concern in a Symptomatic Cat in Spain.

Natural and experimental SARS-CoV-2 infection in pets has been widely evidenced since the beginning of the COVID-19 pandemic. Among the numerous affected animals, cats are one of the most susceptible species. However, little is known about viral pathogenicity and transmissibility in the case of variants of concern (VOCs) in animal hosts, such as the B.1.617.2 (Delta) variant first detected in India. Here, we have identified the B.1.617.2 (Delta) VOC in a cat living with a COVID-19 positive owner. The animal presented mild symptoms (sneezing) and a high viral load was detected in the oropharyngeal swab, suggesting that an active infection was occurring in the upper respiratory tract of the cat. Transmission from the owner to the cat occurred despite the human being fully vaccinated against SARS-CoV-2. This study documents the first detection of B.1.165.2 VOC in a cat in Spain and emphasizes the importance of performing active surveillance and genomic investigation on infected animals.

Nonspecific protection of heat-inactivated Mycobacterium bovis against Salmonella Choleraesuis infection in pigs.

Trained immunity is the capacity of innate immune cells to produce an improved response against a secondary infection after a previous unrelated infection. Salmonellosis represents a public health issue and affects the pig farming industry. In general, vaccination against salmonellosis is still facing problems regarding the control of distinct serovars. Therefore, we hypothesized that an immunostimulant based on heat inactivated Mycobacterium bovis (HIMB) could have an immune training effect in pigs challenged with Salmonella enterica serovar Choleraesuis (S. Choleraesuis) and decided to explore the amplitude of this non-specific immune response. For this purpose, twenty-four 10 days-old female piglets were randomly separated in three groups: immunized group (n = 10) received orally two doses of HIMB prior to the intratracheal S. Choleraesuis-challenge, positive control group (n = 9) that was only challenged with S. Choleraesuis, and negative control group (n = 5) that was neither immunized nor infected. All individuals were necropsied 21 days post-challenge. HIMB improved weight gain and reduced respiratory symptoms and pulmonary lesions caused by S. Choleraesuis in pigs. Pigs immunized with HIMB showed higher cytokine production, especially of serum TNFα and lung CCL28, an important mediator of mucosal trained immunity. Moreover, immunized pigs showed lower levels of the biomarker of lipid oxidation malondialdehyde and higher activity of the antioxidant enzyme superoxide dismutase than untreated challenged pigs. However, the excretion and tissue colonization of S. Choleraesuis remained unaffected. This proof-of-concept study suggests beneficial clinical, pathological, and heterologous immunological effects against bacterial pathogens within the concept of trained immunity, opening avenues for further research.

Molecular detection of Tritrichomonas foetus in bovine samples: a novel real-time polymerase chain reaction (PCR) assay targeting EF1-alpha-Tf1 and a comparative study of published PCR techniques.

The parasite T. foetus causes trichomonosis in cattle but is generally asymptomatic in males. Thus, many bulls carrying the disease go unnoticed, making the detection of T. foetus in bulls an important aspect for its control. Due to drawbacks posed by its cultivation, PCR is a preferred option for diagnostic laboratories. Most published PCR protocols target the genomic region compring the 18S, 5.8S, and 28S rRNA genes and internal transcribed spacers 1 and 2 (rRNA-ITS region), homologous to that of other Tritrichomonas species. There is minimal information on alternative genetic targets and no comparative studies have been published. We compared a protocol based on the microsatellite TfRE (called H94) and five protocols based on the rRNA-ITS region (called M06, M15, G02, G05, and N02). We also designed and evaluated a novel PCR-based assay on the EF1-alpha-Tf1 gene (called V21). The analytical sensitivity and specificity assays for the PCR protocols were performed according to the World Organisation for Animal Health (OIE) directives and the comparative study was performed with a widely used PCR (M06) on clinical samples from 466 breeding bulls. V21 showed a high degree of agreement with our reference M06 (kappa = 0.967), as well as M15 (kappa = 0.958), G05 (kappa = 0.948), and H94 (kappa = 0.986). Protocols H94 and V21 appear to be good approaches for confirming clinical cases in preputial bull samples when genomic regions alternative to rRNA-ITS are required. By contrast, N02 gave false negatives and G02 false positives.

MALDI-TOF Mass Spectrometry as a Rapid Screening Alternative for Non-tuberculous Mycobacterial Species Identification in the Veterinary Laboratory.

Non-tuberculous mycobacteria (NTM) are difficult to identify by biochemical and genetic methods due to their microbiological properties and complex taxonomy. The development of more efficient and rapid methods for species identification in the veterinary microbiological laboratory is, therefore, of great importance. Although MALDI-TOF Mass Spectrometry (MS) has become a promising tool for the identification of NTM species in human clinical practise, information regarding its performance on veterinary isolates is scarce. This study assesses the capacity of MALDI-TOF MS to identify NTM isolates (n = 75) obtained from different animal species. MALDI-TOF MS identified 76.0% (n = 57) and 4% (n = 3) of the isolates with high and low confidence, respectively, in agreement with the identification achieved by Sanger sequencing of housekeeping genes (16S rRNA, hsp65, and rpoB). Thirteen isolates (17.3%) were identified by Sanger sequencing to the complex level, indicating that these may belong to uncharacterised species. MALDI-TOF MS approximated low confidence identifications toward closely related mycobacterial groups, such as the M. avium or M. terrae complexes. Two isolates were misidentified due to a high similarity between species or due to the lack of spectra in the database. Our results suggest that MALDI-TOF MS can be used as an effective alternative for rapid screening of mycobacterial isolates in the veterinary laboratory and potentially for the detection of new NTM species. In turn, Sanger sequencing could be implemented as an additional method to improve identifications in species for which MALDI-TOF MS identification is limited or for further characterisation of NTM species.