Search Results (129)

Mycobacterium avium subsp. hominissuis (MAH) is a zoonotic pathogen with a broad host range and diverse clinical manifestations. We report here the first documented case of MAH-induced fatal vasculitis in zebra finch (Taeniopygia guttata). Histopathological examination revealed acid-fast bacilli within macrophages and endothelial cells, primarily affecting the heart and aorta. Mycobacterial DNA was detected in cloacal swabs from affected finches and environmental samples from their housing facility. PCR targeting the rpoB gene and insertion elements IS1245 and IS901, followed by sequencing, confirmed MAH infection. MAH DNA was identified in 4 of 13 finch cloacal swabs and 7 of 28 environmental samples. This study describes a novel, highly pathogenic manifestation of MAH in birds and underscores the potential for avian involvement in environmental and zoonotic transmission. Full article

Paratuberculosis, caused by Mycobacterium avium subspecies paratuberculosis (MAP), is a chronic granulomatous enteritis with significant implications for ruminant health, economic productivity, and potential zoonotic risk. This study investigated the expression of biomarkers of oxidative stress and apoptosis in goats naturally infected with MAP, focusing on three biological matrices: serum, intestinal mucosa, and mesenteric lymph nodes. Twenty MAP-positive goats and ten healthy controls were included. Serum and tissue levels of malondialdehyde (MDA), glutathione S-transferase (GST), glutathione peroxidase (GPX), superoxide dismutase (SOD), glutathione reductase (GSR), and caspase-3 were quantitatively assessed using ELISA tests. Gross and histopathological analyses confirmed MAP infection. Infected animals showed significantly elevated serum levels of MDA and caspase-3 (p < 0.001), along with decreased antioxidant enzyme activities (GSR, GST, GPX, SOD). Tissue analysis revealed increased MDA and caspase-3 levels, particularly in the intestinal mucosa compared to mesenteric lymph nodes, suggesting localized oxidative damage and apoptosis. Conversely, antioxidant enzyme activity was higher in mesenteric lymph nodes, indicating a compensatory response and a pronounced involvement of the intestinal tract. These findings demonstrate that MAP infection induces marked oxidative stress and apoptotic processes, especially in the intestinal mucosa. The imbalance between pro-oxidant and antioxidant systems may play a key role in the pathogenesis and chronic progression of the disease. Caspase-3 and MDA, in particular, have been identified as promising diagnostic or prognostic biomarkers for MAP infection. This study highlights the importance of developing improved diagnostic tools and therapeutic strategies targeting oxidative stress pathways in paratuberculosis. Full article

This study investigated the genetic diversity of Mycobacterium avium subsp. paratuberculosis (Map)—the causative agent of paratuberculosis—isolated from different host species in Germany. A total of 500 isolates from 243 cattle herds and 9 other host species originating from 13 federal states were genotyped. A multi-target approach was applied, comprising IS900-RFLP with BstEII and PstI digestion; MIRU-VNTR; and SSR1, SSR8, and SSR9 analysis. In total, 93 combined genotypes were identified, 84 in cattle and 21 in non-cattle isolates. Ninety genotypes were assigned to the C-type group, and three genotypes (three from sheep and one from cattle) were assigned to the S-type/subtype III group. Cluster analysis divided genotypes into subgroups similar to those shown for WGS-SNP-based phylogenetic trees. New genotypes were revealed, including INMV262–267 and a specific sequence at locus VNTR7. Five genotypes that were predominant in cattle were also detected in sheep, goats, and deer. The majority of genotypes [61%] were identified only once. Polyclonal infections were observed in individual animals and herds, and various potential Map transmission linkages were uncovered. This high genotype richness of Map reflects the long history of paratuberculosis in Germany and intensive nationwide animal movement and international trading activity. Full article

Background: Bovine tuberculosis (bTB) is an infectious disease which causes significant damage to the farming industry and remains a disease of global significance. Although control strategies have focused on a test and cull approach primarily based around specific cell-mediated immune responses, serological assays are increasingly being used as a supplementary test alongside skin testing and interferon-gamma release (IGRA) assays. The UK is moving towards the use of the Bacillus Calmette–Guérin (BCG) vaccination of cattle as an additional targeted control tool against bTB. However, there are concerns over its potential impact on the outcomes of bTB diagnostic tests and other non-TB assays, such as serological tests for Mycobacterium avium subsp. paratuberculosis (MAP). Methods: We investigated the performance of commercially available serology tests designed to detect bTB and MAP using serum samples from BCG-vaccinated animals which were subsequently infected with Mycobacterium bovis (M. bovis). Results: BCG vaccination per se did not significantly impact the specificity of serological diagnostic tests for bTB or Johne’s disease. However, increased numbers of false-positive responses in bTB serology tests were seen in BCG-vaccinated animals 3 weeks following a tuberculin skin test, where up to 23% and 54% of animals gave a positive result in IDEXX and Enferplex tests, respectively. Furthermore, M. bovis infection gave rise to false-positive test results for Johne’s disease, irrespective of the animals’ prior BCG vaccination status. Conclusions: Caution should be taken when assessing results from serology tests for bTB if tuberculin skin testing has occurred shortly before collection of blood from BCG-vaccinated cattle. Furthermore, these results highlight the potential for misdiagnosis of MAP infection when using serology tests in bTB-infected cattle. Full article

Background: Paratuberculosis (PTB) is a chronic wasting disease mainly caused by Mycobacterium avium subsp. paratuberculosis (MAP) in ruminants. It is difficult to diagnose, prevent, treat, and eradicate, thereby causing serious economic losses to the livestock industry. Therefore, finding a detection method with high sensitivity and specificity is crucial to preventing and controlling PTB. Methods: A total of 1585 fresh fecal samples were collected from 12 prefectures and cities across Inner Mongolia between March 2022 and October 2024. The samples were subjected to pretreatment, followed by DNA extraction. Subsequently, MAP detection and genotyping were performed using a two-step qPCR method. Results: The overall prevalence of MAP in ovines was 3.34% (53/1585), with the prevalence in 12 prefectures and cities ranging from 0% (0/100) to 7.73% (15/194). In the eastern, central, and western regions, the prevalence rates were 4.74% (31/654), 3.68% (14/394), and 1.49% (8/537); in small-scale and intensive farms, they were 3.23% (22/682), and 3.56% (31/903); and in goats and sheep, they were 0.91% (2/219) and 4.98% (36/723), respectively. The overall prevalence rates of C- and S-type MAP were 2.90% (46/1585) and 0.44% (7/1585), respectively. Conclusions: To the best of our knowledge, this study is the first to conduct an epidemiological investigation of PTB in sheep across all nine cities and three leagues in Inner Mongolia and to perform MAP typing on a large scale. It elucidated the differences in the prevalence of PTB in different regions of Inner Mongolia and found that geographical location and sheep breed are potential risk factors for the differences in MAP prevalence. Furthermore, it has been shown that C- and S-type MAP coexist in the eastern and central regions of Inner Mongolia. Full article

Summary-data-based Mendelian randomization (SMR) analysis identified a novel cis-expression quantitative loci (cis-eQTL) associated with the upregulation of the expression of the early growth response factor 4 (EGR4) gene in animals with paratuberculosis (PTB)-associated multifocal lesions, which has been suggested to be modulating the NF-kβ-induced proinflammatory immune response to Mycobacterium avium subsp. paratuberculosis (Map) infection. To confirm these findings and to study the role of EGR4 expression in PTB resilience, the number of EGR4-expressing cells were analysed in paraffin-fixed gut tissues and regional lymph nodes of naturally Map-infected Holstein Friesian cows with focal, multifocal (subclinical and clinical), and diffuse lesions (intermediate and multibacillary), and in controls without lesions by quantitative anti-EGR4 immunohistochemistry. Subclinical animals with multifocal lesions showed a significantly higher number of EGR4-positive cells and were sacrificed at a significantly older average age than the remaining groups (p < 0.001 in all cases). We hypothesize that EGR4 could be mitigating the negative impact of Map infection on host clinical status through its involvement in three molecular mechanisms that promote resilience: (i) limiting NF-kβ-mediated proinflammatory responses, (ii) controlling tissue damage, acting as a brake on T-cell proliferation and cytokine production, and (iii) favouring tissue repair through interaction with epidermal growth factor receptor (EGFR). Full article

The aim of this study was to understand the status of Mycobacterium paratuberculosis infection in a large-scale dairy farm in Xi’an city and evaluate the impact via a “quarantine + elimination” model of bovine paratuberculosis on the production performance, reproductive performance, and economic benefits in said dairy farm. The paratuberculosis antibodies from 4488 dairy cow sera were detected by an ELISA kit, complemented by a comprehensive analysis of milk production parameters, health metrics, reproductive indices, and pharmaceutical expenditures (2021–2024). The results indicated that the paratuberculosis prevalence in the dairy farm gradually reduced from 6.76% (2021) to 3.58% (2024). It was also found that the paratuberculosis prevalence among dairy cows increased progressively with the increase in parity until the fifth calving, after which a significant decline was observed. The reduction in infection rates in the herd was correlated with measurable improvements in milk quality metrics, including elevated milk fat and protein content, extended shelf stability, and decreased somatic cell counts in milk. In addition, the reproductive performance of the dairy cows relatively improved with the decrease in paratuberculosis prevalence; there was a relative improvement in the reproductive performance of the dairy cows, which mainly occurred by the time of pregnancy at the first service of the cows, while the number of monthly occurrences of endometritis, diarrhea, calving intervals, and inseminations decreased. Further data correlation analysis showed that daily milk volume was positively correlated with lactase persistence (95% CI: 0.247–0.753, p = 0.001) and peaked at the day of milk production (95% CI: 0.135–0.698, p = 0.008) but was negatively correlated with parity (95% CI: −0.783–−0.315). In addition, lactation time was positively correlated with 305-day milk volume (95% CI: 0.173–0.718, p < 0.004) and peaked at the day of milk production (95% CI: 0.265–0.761) but showed the opposite trend with the milk fat rate (95% CI: −0.633–−0.018, p = 0.040) and milk protein rate (95% CI: −0.738–−0.215, p = 0.002). Furthermore, milk loss was negatively correlated with peak milk production (95% CI: −0.758–−0.258, p = 0.001). Intriguingly, the cost of medications for diarrhea exhibited a downward trend over the past three years. Taken together, these findings confirmed the necessity to reduce the incidence of Mycobacterium avium subsp. paratuberculosis in dairy cows and serve as a guide for the future successful and gradual eradication of paratuberculosis in Chinese dairy cow farms. Full article

Background/Objectives: Mycobacterium abscessus (MAB) is a highly resilient pathogen that causes difficult-to-treat pulmonary infections, particularly in individuals with cystic fibrosis (CF) and other underlying conditions. Its ability to form robust biofilms within the CF lung environment is a major factor contributing to its resistance to antibiotics and evasion of the host immune response, making conventional treatments largely ineffective. These biofilms, encased in an extracellular matrix, enhance drug tolerance and facilitate metabolic adaptations in hypoxic conditions, driving the bacteria into a persistent, non-replicative state that further exacerbates antimicrobial resistance. Treatment options remain limited, with multidrug regimens showing low success rates, highlighting the urgent need for more effective therapeutic strategies. Methods: In this study, we employed artificial sputum media to simulate the CF lung environment and conducted high-throughput screening of 24,000 compounds from diverse chemical libraries to identify inhibitors of MAB biofilm formation, using the Crystal Violet (CV) assay. Results: The screen established 17 hits with ≥30% biofilm inhibitory activity in mycobacteria. Six of these compounds inhibited MAB biofilm formation by over 60%, disrupted established biofilms by ≥40%, and significantly impaired bacterial viability within the biofilms, as confirmed by reduced CFU counts. In conformational assays, select compounds showed potent inhibitory activity in biofilms formed by clinical isolates of both MAB and Mycobacterium avium subsp. hominissuis (MAH). Key compounds, including ethacridine, phenothiazine, and fluorene derivatives, demonstrated potent activity against pre- and post-biofilm conditions, enhanced antibiotic efficacy, and reduced intracellular bacterial loads in macrophages. Conclusions: This study results underscore the potential of these compounds to target biofilm-associated resistance mechanisms, making them valuable candidates for use as adjuncts to existing therapies. These findings also emphasize the need for further investigations, including the initiation of a medicinal chemistry campaign to leverage structure–activity relationship studies and optimize the biological activity of these underexplored class of compounds against nontuberculous mycobacterial (NTM) strains. Full article

Paratuberculosis (PTB), primarily caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a chronic infection that affects ruminants and is difficult to prevent, diagnose, and treat. Investigating how MAP infections affect the gut microbiota in sheep can aid in the prevention and treatment of ovine PTB. This study examined fecal samples from eight small-tail Han sheep (STHS) at various stages of infection and from three different field areas. All samples underwent DNA extraction and 16S rRNA sequencing. Among all samples, the phyla p. Firmicutes and p. Bacteroidota exhibited the highest relative abundance. The dominant genera in groups M1–M6 were UCG-005, Christensenellaceae_R-7_group, Rikenellaceae_RC9_gut_group, Akkermansia, UCG-005, and Bacteroides, whereas those in groups A–C were Christensenellaceae_R-7_group, Escherichia–Shigella, and Acinetobacter, respectively. The microbial community structure varied significantly among groups M1–M6. Specifically, 56 microbiota consortia with different taxonomic levels, including the order Clostridiales, were significantly enriched in groups M1–M6, whereas 96 microbiota consortia at different taxonomic levels, including the family Oscillospiraceae, were significantly enriched in groups A–C. To the best of our knowledge, this is the first study to report that MAP infection alters the intestinal microbiota of STHS. Changes in p. Firmicutes abundance can serve as a potential biomarker to distinguish MAP infection and determine the infection stage for its early diagnosis. Our study provides a theoretical basis for the treatment of PTB by regulating the intestinal microbiota, including p. Firmicutes. Full article

Mycobacterium avium subsp. paratuberculosis (MAP) is known to cause paratuberculosis. One notable protein, MAP3773c, plays a critical role in iron metabolism as a transcription factor. This study aims to investigate the binding affinity of MAP3773c to the chromatin of the Ferroportin1 (FPN1) gene in murine macrophage J774 A.1. We conducted a sequence alignment to identify potential interaction sites for MAP3773c. Following this, we used in silico analysis to predict binding interactions, complemented by electrophoretic mobility shift assay (EMSA) to confirm in vitro binding of MAP3773c. The map3773c gene was cloned into the pcDNA3.1 vector, with subsequent expression analysis carried out via Western blotting and real-time PCR. Chromatin immunoprecipitation (CHiP) assays were performed on transfected macrophages to confirm binding in the native chromatin context. Our in silico and in vitro analysis indicated that MAP3773c interacts with two binding motifs within the FPN1 coding region. The ChiP results provided additional validation, demonstrating the binding of MAP3773c to the FPN1 chromatin through successful amplification of the associated chromatin fragment via PCR. Our study demonstrated that MAP3773c binds to FPN1 and provides insight into the role of MAP3773c and its effect on host iron transport. Full article

Paratuberculosis is a debilitating disease of ruminants that causes significant economic loss in both cattle and sheep. Early detection of the disease is crucial to controlling the disease; however, current diagnostic tests lack sensitivity. This study evaluated the potential for volatile organic compounds (VOCs) detected by gas chromatography and an electronic nose (eNose) for use as diagnostic tools to differentiate between Map-infected and non-infected cattle and sheep. Solid-phase micro-extraction gas chromatography–mass spectrometry (SPME GC-MS) was used to quantify VOCs from the headspace of faecal samples (cattle and sheep), and partial least squares–discriminant analysis (PLS-DA) was used to determine the suitability as a diagnostic tool. Both the cattle and sheep models had high specificity and sensitivity, 98.1% and 92.3%, respectively, in cattle, and both were 100% in sheep. The eNose was also able to discriminate between Map-infected and non-infected sheep and cattle with 88.9% specificity and 100% sensitivity in sheep and 100% specificity and sensitivity in cattle. This is the first time that VOC analysis by eNose and GCMS has been used for identification of Map in cattle and sheep faeces. GCMS also allowed the identification of putative disease biomarkers, and the eNose diagnostic capability suggests it is a promising tool for point-of-care diagnosis for Map detection on farms. Full article

Background/Objectives: Developing interventions for Johne’s disease, which focuses on controlling Mycobacterium avium subsp. paratuberculosis (MAP) in contaminated environments by treating infected cows and preventing transmission from diseased animals, is a critical priority. Bacteriophage (phage) therapy, an emerging biological intervention, offers a promising alternative for the treatment and management of MAP infections. Methods: In this study, we generated an MAP-specific lytic phage library aimed at characterizing the therapeutic potential of phages under environmental and biological conditions that mimic those encountered in infected cattle such as ruminal fluid, milk, colostrum, and the bovine intestinal epithelium, a key site of MAP colonization and, later, transmission. Results: Our library contains a diverse collection of phages that have demonstrated robust lytic activity against MAP. The host range of these phages was thoroughly assessed, revealing that several isolates produce clear plaques on a range of MAP strains, as well as other pathogenic non-tuberculous mycobacterial (NTM) species and M. tuberculosis strains. This broad host range expands the therapeutic potential of the phage collection, positioning it as a potential cross-species antimicrobial tool. In vitro tests under conditions replicating the rumen, milk, and colostrum environments show that selected phages maintain stability and lytic efficacy, even in the presence of complex biological fluids. Furthermore, a subset of these phages was capable of preventing MAP colonization and invasion in cultured bovine epithelial cells, suggesting their potential for direct prophylactic application in cattle. Conclusions. Our collection of MAP phages represents a valuable source that can be developed into probiotic-like preparations, offering a cost-effective solution for prophylaxis and control of Johne’s disease. Full article

Johne’s disease (JD), also known as paratuberculosis, is a chronic, untreatable gastroenteritis of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP) infection. Evidence for host genetic resistance to disease progression exists, although it is limited due to the extended incubation period (years) and diagnostic challenges. To overcome this, previously restored formalin-fixed paraffin embedded tissue (FFPE) DNA from archived FFPE tissue cassettes was utilized for a novel retrospective case-control genome-wide association study (GWAS) on ovine JD. Samples from known MAP-infected flocks with ante- and postmortem diagnostic data were used. Cases (N = 9) had evidence of tissue infection, compared to controls (N = 25) without evidence of tissue infection despite positive antemortem diagnostics. A genome-wide efficient mixed model analysis (GEMMA) to conduct a GWAS using restored FFPE DNA SNP results from the Illumina Ovine SNP50 Bead Chip, identified 10 SNPs reaching genome-wide significance of p < 1 × 10⁻⁶ on chromosomes 1, 3, 4, 24, and 26. Pathway analysis using PANTHER and the Kyoto Encyclopedia of Genes and Genomes (KEGG) was completed on 45 genes found within 1 Mb of significant SNPs. Our work provides a framework for the novel use of archived FFPE tissues for animal genetic studies in complex diseases and further evidence for a genetic association in JD. Full article

Paratuberculosis or Johne’s disease (JD), a chronic granulomatous gastroenteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP), causes huge economic losses and reduces animal welfare in dairy cattle herds worldwide. At present, molecular mechanisms and biological functions involved in immune responses to MAP infection of dairy cattle are not clearly understood. Our purpose was to integrate transcriptomic profiles and competing endogenous RNA (ceRNA) network analyses to identify key messenger RNAs (mRNAs) and regulatory RNAs involved in molecular regulation of peripheral blood mononuclear cells (PBMCs) for MAP infection in dairy cattle. In total, 28 lncRNAs, 42 miRNAs, and 370 mRNAs were identified by integrating gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. In this regard, we identified 21 hub genes (CCL20, CCL5, CD40, CSF2, CXCL8, EIF2AK2, FOS, IL10, IL17A, IL1A, IL1B, IRF1, MX2, NFKB1, NFKBIA, PTGS2, SOCS3, TLR4, TNF, TNFAIP3, and VCAM1) involved in MAP infection. Furthermore, eight candidate subnets with eight lncRNAs, 29 miRNAs, and 237 mRNAs were detected through clustering analyses, whereas GO enrichment analysis of identified RNAs revealed 510, 22, and 11 significantly enriched GO terms related to MAP infection in biological process, molecular function, and cellular component categories, respectively. The main metabolic-signaling pathways related to MAP infection that were enriched included the immune system process, defense response, response to cytokine, leukocyte migration, regulation of T cell activation, defense response to bacterium, NOD-like receptor, B cell receptor, TNF, NF-kappa B, IL-17, and T cell receptor signaling pathways. Contributions of transcriptome profiles from MAP-positive and MAP-negative sample groups plus a ceRNA regulatory network underlying phenotypic differences in the intensity of pathogenicity of JD provided novel insights into molecular mechanisms associated with immune system responses to MAP infection in dairy cattle. Full article

Mycobacterium avium subsp. avium is pathogenic mainly to birds, although cases of mycobacteriosis caused by these bacteria have also been reported in other animals and humans. Not much is known about the effects of this pathogen on otters. The aim of this study was to report for the first time the isolation of M. avium subsp. avium in wild otter and to describe its multidrug resistance profile. A female otter injured in a car accident was found dead and subjected to postmortem examination. Apart from the trauma changes, no other macroscopic pathological changes were detected. Bacteriologic examination revealed the presence of acid-fast bacilli in the lymph nodes, which were confirmed by molecular methods as M. avium subsp. avium. Antimicrobial susceptibility testing revealed susceptibility to clarithromycin and amikacin, but resistance to linezolid, moxifloxacin, streptomycin, isoniazid, trimethoprim/sulfamethoxazole, ciprofloxacin, doxycycline, and ethionamide. This is unusual for wild species, which generally should not come into contact with antimicrobials, and may suggest that multidrug-resistant MAC strains are circulating between wild and domestic animals. These results emphasise the need for additional epidemiological studies on non-tuberculous mycobacteria in wildlife and their implications for one health. Full article