Multidrug-resistant strains of Mycobacterium complex species in Egyptian farm animals, veterinarians, and farm and abattoir workers

A bovine pulmosphere model and multiomics reveal early host response signature in tuberculosis

Early interactions between tubercle bacilli and lung cells are critical in tuberculosis (TB) pathogenesis. Conventional two-dimensional cell cultures fail to replicate the multicellular complexity of lungs. We introduce a three-dimensional pulmosphere model for Mycobacterium tuberculosis infection in bovine systems, demonstrating through comprehensive transcriptome and proteome analyses that these multicellular spheroids closely mimic lung cell diversity, interactions, and extracellular matrix (ECM) composition. Cell viability, hypoxia, and reactive oxygen species assessments over three weeks confirm the model's suitability. To establish infection, we employed M. bovis BCG-an attenuated vaccine strain, and M. tuberculosis H37Rv-a laboratory adapted human clinical strain that is attenuated for cattle infection compared to M. bovis. Both infection upregulated key host pathways; however, M. tuberculosis induced distinct responses, including enhanced ECM receptors expression, neutrophil chemotaxis, interferon signaling, and RIG-1 signaling. A six genes/protein signature- IRF1, CCL5, CXCL8, CXCL10, SERPINE1, and CFB -emerges as an early host response marker to M. tuberculosis infection. Infection with virulent M. bovis and M. orygis revealed a shared upregulated gene signature across Mycobacterium tuberculosis complex species, but with pathogen-specific variations. This study presents a robust ex vivo bovine pulmosphere TB model with implications in biomarkers discovery, high-throughput drug screening, and TB control strategies.

Recent progress in the genotyping of bovine tuberculosis and its rapid diagnosis via nanoparticle-based electrochemical biosensors

Bovine tuberculosis (bTB) is considered a worldwide infectious zoonotic disease. Mycobacterium bovis causes bTB disease. It is one of the Mycobacterium tuberculosis complex (MTBC) members. MTBC is a clonal complex of close relatives with approximately 99.95% similarity. M. bovis is a spillover pathogen that can transmit from animals to humans and rarely from humans to animals with contact. Genotyping techniques are important to discriminate and differentiate between MTBC species. Spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) are widely used but they have some limitations. As an alternative, whole genome sequencing approaches have been utilized due to their high-resolution power. They are employed in typing M. bovis and explain the evolutionary and phylogenetic relationships between isolates. The control of bTB disease has attracted a large amount of attention. Rapid and proper diagnosis is necessary for monitoring the disease as an initial step for its control and treatment. Nanotechnology has a potential impact on the rapid diagnosis and treatment of bTB through the use of nanocarrier and metal nanoparticles (NPs). Special attention has been paid to voltammetric and impedimetric electrochemical strategies as facile, sensitive, and selective methods for the efficient detection of tuberculosis. The efficacy of these sensors is enhanced in the presence of NPs, which act as recognition and/or redox probes. Gold, silver, copper, cobalt, graphene, and magnetic NPs, as well as polypyrrole nanowires and multiwalled carbon nanotubes have been employed for detecting tuberculosis. Overall, NP-based electrochemical sensors represent a promising tool for the diagnosis of bTB.

Zoonotic Tuberculosis: A Neglected Disease in the Middle East and North Africa (MENA) Region

Mycobacterium bovis is the etiologic agent of bovine tuberculosis (BTB), a serious infectious disease in both humans and animals. BTB is a zoonotic disease primarily affecting cattle and occasionally humans infected through close contact with infected hosts or the consumption of unpasteurized dairy products. Zoonotic tuberculosis is strongly associated with poverty and poor hygiene, and low- and middle-income countries bear the brunt of the disease. BTB has been increasingly recognized as a growing public health threat in developing countries. However, the lack of effective surveillance programs in many of these countries poses a barrier to accurately determining the true burden of this disease. Additionally, the control of BTB is threatened by the emergence of drug-resistant strains that affect the effectiveness of current treatment regimens. Here, we analyzed current trends in the epidemiology of the disease as well as the antimicrobial susceptibility patterns of M. bovis in the Middle East and North Africa (MENA) region, a region that includes several developing countries. Following PRISMA guidelines, a total of 90 studies conducted in the MENA region were selected. Our findings revealed that the prevalence of BTB among humans and cattle varied significantly according to the population size and country in the MENA region. Most of the available studies were based on culture and/or PCR strategies and were published without including data on antimicrobial resistance and molecular typing. Our findings highlighted the paramount need for the use of appropriate diagnostic tools and the implementation of sustainable control measures, especially at the human/animal interface, in the MENA region.

Review on Bovine Tuberculosis: An Emerging Disease Associated with Multidrug-Resistant Mycobacterium Species

Bovine tuberculosis is a serious infectious disease affecting a wide range of domesticated and wild animals, representing a worldwide economic and public health burden. The disease is caused by Mycobacteriumbovis and infrequently by other pathogenic mycobacteria. The problem of bovine tuberculosis is complicated when the infection is associated with multidrug and extensively drug resistant M. bovis. Many techniques are used for early diagnosis of bovine tuberculosis, either being antemortem or postmortem, each with its diagnostic merits as well as limitations. Antemortem techniques depend either on cellular or on humoral immune responses, while postmortem diagnosis depends on adequate visual inspection, palpation, and subsequent diagnostic procedures such as bacterial isolation, characteristic histopathology, and PCR to reach the final diagnosis. Recently, sequencing and bioinformatics tools have gained increasing importance for the diagnosis of bovine tuberculosis, including, but not limited to typing, detection of mutations, phylogenetic analysis, molecular epidemiology, and interactions occurring within the causative mycobacteria. Consequently, the current review includes consideration of bovine tuberculosis as a disease, conventional and recent diagnostic methods, and the emergence of MDR-Mycobacterium species.

Comparative diagnosis of bovine tuberculosis using single intradermal cervical tuberculin technique, conventional methods, enzyme-linked immunosorbent assay, and the gamma-interferon assay

Background and Aim

Bovine tuberculosis (TB) is a zoonotic disease that causes huge economic losses. This study aimed to compare the result obtained from the single intradermal test, conventional methods (culture and microscopy), gamma-interferon (IFN-γ) assay, and indirect enzyme-linked immunosorbent assay (ELISA) to diagnose bovine TB.

Materials and Methods

This study evaluated 2913 animals from milk farms in Cairo, El-Sharkia, and El-Qalyubia Governorates by single intradermal cervical tuberculin technique (SICTT), ELISA, and IFN-γ assay.

Results

Of the 2913 dairy cows surveyed, 3.7% yielded positive results. Culture prepared samples on Lowenstein-Jensen and Middlebrook 7H10 agar media yielded 52 (1.85%) isolates of Mycobacterium spp. from 2805 milk samples that yielded negative tuberculin reactions and 56 (51.85%) isolates of Mycobacterium spp. were recovered from 108 lymph node samples from positive cases. ELISA analysis of the sera of 108 positive SICTT reactors revealed that 94 (87.03%) and 97 (89.81%) animals were positive for bovine purified protein derivative (PPD-B) antigen and commercial polypeptide antigen, respectively. IFN-γ assays were performed on whole blood samples collected from positive SICTT reactors and showed that 103 (95.37%) animals were positive.

Conclusion

M. tuberculosis complex may be isolated from raw milk and not all infected animals shed mycobacterial bacilli in their milk. The use of polypeptide antigen in ELISA provides better diagnostic efficacy than PPD-B antigen. The IFN-γ assay is more sensitive than both SICTT and ELISA. It should be used in parallel with SICTT to allow the detection of more positive animals before they become a source of infection to other animals and humans.

Prevalence of Mycobacterium bovis in milk on dairy cattle farms: An international systematic literature review and meta-analysis

Bovine tuberculosis, caused by Mycobacterium bovis (M. bovis), is a globally distributed chronic disease of animals. The bacteria can be transmitted to humans via the consumption of unpasteurised (raw) milk, thus representing an important public health risk. To investigate the risk of zoonotic transmission of M. bovis via raw milk, this study systematically reviewed published studies to estimate the prevalence of M. bovis in on-farm bulk-tank milk (BTM) and individual cow's milk (IM) by meta-analysis. In total, 1,339 articles were identified through seven electronic databases and initially screened using titles and abstracts. The quality of 108 potentially relevant articles was assessed using full texts, and 67 articles comprising 83 studies (76 IM and 7 BTM), were included in the meta-analysis. The prevalence of M. bovis in IM and BTM was summarised according to the diagnostic test used, and the tuberculin skin test (TST) infection status of the individual cows (for IM) or herds (for BTM). Heterogeneity was quantified using the I-squared statistic. Prediction intervals (95% PIs) were also estimated. For IM, the overall prevalence was summarised at 5% (95%CI: 3%-7%). In TST positive cows, prevalence was summarised at 8% (95%CI: 4%-13%). For BTM, the overall prevalence independent of individual herd TST infection status was summarised at 5% (95%CI: 0%-21%). There was considerable heterogeneity evident among the included studies, while PIs were also wide. Inconsistency in the quality of reporting was also observed resulting in missing information, such as the TST infection status of the individual animal/herd. No study reported the number of M. bovis bacteria in test-positive milk samples. Several studies reported the detection of M. tuberculosis and M. africanum in milk. Despite international efforts to control tuberculosis, this study highlights the risk of zoonotic transmission of M. bovis via unpasteurised milk and dairy products made using raw milk.