Mycobacterial infection aggravates Helicobacter pylori-induced gastric preneoplastic pathology by redirection of de novo induced Treg cells

The two human pathogens Helicobacter pylori and Mycobacterium tuberculosis (Mtb) co-exist in many geographical areas of the world. Here, using a co-infection model of H. pylori and the Mtb relative M. bovis bacillus Calmette-Guérin (BCG), we show that both bacteria affect the colonization and immune control of the respective other pathogen. Co-occurring M. bovis boosts gastric Th1 responses and H. pylori control and aggravates gastric immunopathology. H. pylori in the stomach compromises immune control of M. bovis in the liver and spleen. Prior antibiotic H. pylori eradication or M. bovis-specific immunization reverses the effects of H. pylori. Mechanistically, the mutual effects can be attributed to the redirection of regulatory T cells (Treg cells) to sites of M. bovis infection. Reversal of Treg cell redirection by CXCR3 blockade restores M. bovis control. In conclusion, the simultaneous presence of both pathogens exacerbates the problems associated with each individual infection alone and should possibly be factored into treatment decisions.

PM2.5 mediated alterations in the in vitro human granuloma and its effect on reactivation of mycobacteria

Exposure to particulate matter pollutant PM_2.5 diminishes the immune response to mycobacterial antigens relevant to contain the infection in the granuloma, thus leading to reactivation of latent bacilli. The present study was therefore designed based on the hypothesis that exposure to PM_2.5 affects the granuloma formation and reactivation of latent mycobacterial bacilli contained in the granuloma. For the sampling of PM_2.5, based on initial standardisations, Teflon filter was selected over the quartz filter. Two different approaches were used to study the effect of PM_2.5 on the human PBMC granuloma formed by Mycobacterium bovis BCG at multiplicity of infection (MOI) 0.1. In the first approach, granuloma formed in the presence of PM_2.5 was loosely packed and ill-defined with significant downregulation of dormancy-associated mycobacterial genes, upregulation of reactivation-associated rpfB gene along with a significant increase in TNFα level without any change in the bacterial load in terms of CFUs. In the second approach, preformed human PBMC granuloma using M. bovis BCG was treated with PM_2.5 that resulted in the disruption of granuloma architecture along with downregulation of not only dormancy-associated genes but also reactivation-associated rpfB gene of mycobacterial bacilli recovered from granuloma. However, there was no significant change in the host cytokine levels. Therefore, it can be inferred that PM_2.5 can modulate the granuloma formation in vitro as well as mycobacterial gene expression in the granuloma with a possible role in the reactivation of latent bacilli.

Recombinant ArgF PLGA nanoparticles enhances BCG induced immune responses against Mycobacterium bovis infection

Mycobacterium bovis (M. bovis) is a member of mycobacterium tuberculosis complex (MTBC), and a causative agent of chronic respiratory disease in a wide range of hosts. Bacillus Calmette-Guerin (BCG) vaccine is mostly used for the prevention of childhood tuberculosis. Further substantial implications are required for the development and evaluation of new tuberculosis (TB) vaccines as well as improving the role of BCG in TB control strategies. In this study, we prepared PLGA nanoparticles encapsulated with argF antigen (argF-NPs). We hypothesized, that argF nanoparticles mediate immune responses of BCG vaccine in mice models of M. bovis infection. We observed that mice vaccinated with argF-NPs exhibited a significant increase in secretory IFN-γ, CD4+ T cells response and mucosal secretory IgA against M. bovis infection. In addition, a marked increase was observed in the level of secretory IL-1β, TNF-α and IL-10 both in vitro and in vivo upon argF-NPs vaccination. Furthermore, argF-NPs vaccination resulted in a significant reduction in the inflammatory lesions in the lung's tissues, minimized the losses in total body weight and reduced M. bovis burden in infected mice. Our results indicate that BCG prime-boost strategy might be a promising measure for the prevention against M. bovis infection by induction of CD4+ T cells responses and mucosal antibodies.

Simulating the next steps in badger control for bovine tuberculosis in England

Industry-led culling of badgers has occurred in England to reduce the incidence of bovine tuberculosis in cattle for a number of years. Badger vaccination is also possible, and a move away from culling was "highly desirable" in a recent report to the UK government. Here we used an established simulation model to examine badger control option in a post-cull environment in England. These options included no control, various intermittent culling, badger vaccination and use of a vaccine combined with fertility control. The initial simulated cull led to a dramatic reduction in the number of infected badgers present, which increased slowly if there was no further badger management. All three approaches led to a further reduction in the number of infected badgers, with little to choose between the strategies. We do note that of the management strategies only vaccination on its own leads to a recovery of the badger population, but also an increase in the number of badgers that need to be vaccinated. We conclude that vaccination post-cull, appears to be particularly effective, compared to vaccination when the host population is at carrying capacity.

Tissue specific diversification, virulence and immune response to Mycobacterium bovis BCG in a patient with an IFN-γ R1 deficiency

Summary: We characterized Mycobacterium bovis BCG isolates found in lung and brain samples from a previously vaccinated patient with IFNγR1 deficiency. The isolates collected displayed distinct genomic and phenotypic features consistent with host adaptation and associated changes in antibiotic susceptibility and virulence traits. Background: We report a case of a patient with partial recessive IFNγR1 deficiency who developed disseminated BCG infection after neonatal vaccination (BCG-vaccine). Distinct M. bovis BCG-vaccine derived clinical strains were recovered from the patient's lungs and brain. Methods: BCG strains were phenotypically (growth, antibiotic susceptibility, lipid) and genetically (whole genome sequencing) characterized. Mycobacteria cell infection models were used to assess apoptosis, necrosis, cytokine release, autophagy, and JAK-STAT signaling. Results: Clinical isolates BCG-brain and BCG-lung showed distinct Rv0667 rpoB mutations conferring high- and low-level rifampin resistance; the latter displayed clofazimine resistance through Rv0678 gene (MarR-like transcriptional regulator) mutations. BCG-brain and BCG-lung showed mutations in fadA2, fadE5, and mymA operon genes, respectively. Lipid profiles revealed reduced levels of PDIM in BCG-brain and BCG-lung and increased TAGs and Mycolic acid components in BCG-lung, compared to parent BCG-vaccine. In vitro infected cells showed that the BCG-lung induced a higher cytokine release, necrosis, and cell-associated bacterial load effect when compared to BCG-brain; conversely, both strains inhibited apoptosis and altered JAK-STAT signaling. Conclusions: During a chronic-disseminated BCG infection, BCG strains can evolve independently at different sites likely due to particular microenvironment features leading to differential antibiotic resistance, virulence traits resulting in dissimilar responses in different host tissues.

GPR183 Regulates Interferons, Autophagy, and Bacterial Growth During Mycobacterium tuberculosis Infection and Is Associated With TB Disease Severity

Oxidized cholesterols have emerged as important signaling molecules of immune function, but little is known about the role of these oxysterols during mycobacterial infections. We found that expression of the oxysterol-receptor GPR183 was reduced in blood from patients with tuberculosis (TB) and type 2 diabetes (T2D) compared to TB patients without T2D and was associated with TB disease severity on chest x-ray. GPR183 activation by 7α,25-dihydroxycholesterol (7α,25-OHC) reduced growth of Mycobacterium tuberculosis (Mtb) and Mycobacterium bovis BCG in primary human monocytes, an effect abrogated by the GPR183 antagonist GSK682753. Growth inhibition was associated with reduced IFN-β and IL-10 expression and enhanced autophagy. Mice lacking GPR183 had significantly increased lung Mtb burden and dysregulated IFNs during early infection. Together, our data demonstrate that GPR183 is an important regulator of intracellular mycobacterial growth and interferons during mycobacterial infection.

Modelling early events in Mycobacterium bovis infection using a co-culture model of the bovine alveolus

Bovine tuberculosis (bTB), a zoonosis mainly caused by Mycobacterium bovis has severe socio-economic consequences and impact on animal health. Host-pathogen interactions during M. bovis infection are poorly understood, especially early events which are difficult to follow in vivo. This study describes the utilisation of an in vitro co-culture model, comprising immortalised bovine alveolar type II (BATII) epithelial cells and bovine pulmonary arterial endothelial cells (BPAECs). When cultured at air-liquid interface, it was possible to follow the migration of live M. bovis Bacille Calmette-Guérin (BCG) and to observe interactions with each cell type, alongside cytokine release. Infection with BCG was shown to exert a detrimental effect primarily upon epithelial cells, with corresponding increases in IL8, TNFα, IL22 and IL17a cytokine release, quantified by ELISA. BCG infection increased expression of CD54, MHC Class I and II molecules in endothelial but not epithelial cells, which exhibited constitutive expression. The effect of peripheral blood mononuclear cell conditioned medium from vaccinated cattle upon apical-basolateral migration of BCG was examined by quantifying recovered BCG from the apical, membrane and basolateral fractions over time. The numbers of recovered BCG in each fraction were unaffected by the presence of PBMC conditioned medium, with no observable differences between vaccinated and naïve animals.

The In Vitro M1/M2 Polarization of Macrophages of BCG-Infected Mice

Cultured peritoneal macrophages from intact (control) and BCG-infected (experiment) male BALB/c mice were studied 90 days after infection. Polarization of macrophages by M1 (expression of GM-CSF, IFN_γ, and CD16/32) and M2 (expression of bFGF and CD36) differentiation pathways was studied with consideration for their the nuclearity class. Mononuclear cells predominated (90% and higher) in macrophage cultures of both groups and presumably, were presented by mainly epithelioid cells. The results indicated polarization of mononuclear and multinuclear macrophages in the M2 direction under conditions of BCG granulomatosis and a higher initial M2 polarization of binuclear macrophages. In control cultures, the ratio of M2 to M1 macrophages was 0.57, in experimental cultures this ratio was 1.6. It seems that long persistence of Mycobacterium tuberculosis in macrophages served as a factor stimulating the plastic processes and transformation of macrophages into epithelioid cells that form the "core" of granulomas and their enlargement upon incorporation of macrophages.

Citrate lyase CitE in Mycobacterium tuberculosis contributes to mycobacterial survival under hypoxic conditions

Mycobacterium tuberculosis is the causative agent of tuberculosis and has evolved an ability to survive in hostile host environments. M. tuberculosis is thought to utilize the rTCA cycle to sustain its latent growth during infection, but the enzymatic characteristics and physiological function for the key citrate lyase of the rTCA cycle, MtbCitE, in the important pathogen remain unclear. In this study, we investigated the function of MtbCitE based on its structural properties and sequence comparisons with other bacterial citrate lyase subunits. We showed that several amino acid residues were important for the citrate cleavage activity of MtbCitE. Strikingly, the citrate cleavage activity of MtbCitE was inhibited by ATP, indicating that energy metabolism might couple with the regulation of MtbCitE activity, which differed from other CitEs. More interestingly, deletion of citE from Mycobacterium bovis BCG decreased the mycobacterial survival rate under hypoxic conditions, whereas complementation with citE restored the phenotype to wild-type levels. Consistently, three key rTCA cycle enzymes were positively regulated under hypoxic conditions in mycobacteria. Therefore, we characterized a unique citrate lyase MtbCitE from M. tuberculosis and found that the CitE protein significantly contributed to mycobacterial survival under hypoxic conditions.

Co-infection of cattle with Fasciola hepatica or F. gigantica and Mycobacterium bovis: A systematic review

The liver flukes, Fasciola hepatica and F. gigantica, are common trematode parasites of livestock. F. hepatica is known to modulate the immune response, including altering the response to co-infecting pathogens. Bovine tuberculosis (bTB), caused by Mycobacterium bovis, is a chronic disease which is difficult to control and is of both animal welfare and public health concern. Previous research has suggested that infection with liver fluke may affect the accuracy of the bTB skin test, but direction of the effect differs between studies. In a systematic review of the literature, all experimental and observational studies concerning co-infection with these two pathogens were sought. Data were extracted on the association between fluke infection and four measures of bTB diagnosis or pathology, namely, the bTB skin test, interferon γ test, lesion detection and culture/bacterial recovery. Of a large body of literature dating from 1950 to 2019, only thirteen studies met the inclusion criteria. These included studies of experimentally infected calves, case control studies on adult cows, cross sectional abattoir studies and a herd level study. All the studies had a medium or high risk of bias. The balance of evidence from the 13 studies included in the review suggests that liver fluke exposure was associated with either no effect or a decreased response to all of the four aspects of bTB diagnosis assessed: skin test, IFN γ, lesion detection and mycobacteria cultured or recovered. Most studies showed a small and/or non-significant effect so the clinical and practical importance of the observed effect is likely to be modest, although it could be more significant in particular groups of animals, such as dairy cattle.

Assessing effects from four years of industry-led badger culling in England on the incidence of bovine tuberculosis in cattle, 2013-2017

The objective was to measure the association between badger culling and bovine tuberculosis (TB) incidents in cattle herds in three areas of England between 2013-2017 (Gloucestershire and Somerset) and 2015-2017 (Dorset). Farming industry-selected licensed culling areas were matched to comparison areas. A TB incident was detection of new Mycobacterium bovis infection (post-mortem confirmed) in at least one animal in a herd. Intervention and comparison area incidence rates were compared in central zones where culling was conducted and surrounding buffer zones, through multivariable Poisson regression analyses. Central zone incidence rates in Gloucestershire (Incidence rate ratio (IRR) 0.34 (95% CI 0.29 to 0.39, p < 0.001) and Somerset (IRR 0.63 (95% CI 0.58 to 0.69, p < 0.001) were lower and no different in Dorset (IRR 1.10, 95% CI 0.96 to 1.27, p = 0.168) than comparison central zone rates. The buffer zone incidence rate was lower for Gloucestershire (IRR 0.64, 95% CI 0.58 to 0.70, p < 0.001), no different for Somerset (IRR 0.97, 95% CI 0.80 to 1.16, p = 0.767) and lower for Dorset (IRR 0.45, 95% CI 0.37 to 0.54, p < 0.001) than comparison buffer zone rates. Industry-led culling was associated with reductions in cattle TB incidence rates after four years but there were variations in effects between areas.

Outcome of inadvertent high dose BCG administration in newborns at a tertiary care hospital, Karachi- Case series

Bacillus Calmette-Guérin (BCG) vaccine is given to newborns soon after birth. BCG vaccine overdose has been rarely reported. Here we report the outcome of newborns who accidently received high dose BCG at a tertiary care hospital, Karachi. We reviewed records of 26 newborns, who accidentally received intradermal high dose BCG, used for the treatment of urinary bladder cancers and 80 times higher dose than the BCG used for routine vaccination. The incident happened from 14-16^th April, 2016 at Aga Khan University Hospital, Karachi. Analysis was carried out using SPSS. A total of 23/26(88.5%) newborns were followed for atleast 3 months and 11/26 (42.3%) were followed for atleast one year. 13/26 (50%) were male. All 26 patients were prescribed isoniazid and rifampicin for 3 months. 3/26 (11.5%) were lost to follow-up before completion of anti-tuberculous drugs (ATT). Lesions at the BCG site were observed in 16/26 (61.5%) infants, of which 15 (93.8%) had a papule, 3 (18.8%) developed a pustule, 3 (18.8%) had skin induration and 2 (12.5%) had skin erythema. Axillary lymphadenopathy was observed in 1/26 (3.8%) patient. Coagulation was deranged in 3/26 (11.5%) of babies. Intracranial bleeding was observed in 1/26 (3.8%) case. Localized skin lesions were the most common adverse events. None of them developed clinical tuberculosis. Chemoprophylaxis for inadvertent high dose BCG administration should be given for atleast 3 months. Furthermore, vigilant follow-up, transparency and disclosure are the vital steps in the management of any medical error.

Predicting badger visits to farm yards and making predictions available to farmers

The use of agricultural resources or environments by wildlife may result in opportunities for transmission of infections amongst wild animals, livestock and humans. Targeted use of biosecurity measures may therefore reduce disease risks, although this requires practical knowledge of where such measures would be most effective, and effective means of communicating risks so that stakeholders can make informed decisions about such investment. In parts of Europe, the European badger Meles meles may act as a wildlife reservoir for Mycobacterium bovis, the causative agent of bovine tuberculosis, and badger visits to farmyards may provide potential opportunities for transmission of M. bovis to cattle. Biosecurity measures are effective in reducing badger activity in farmyards, although it is unclear which farms should be targeted with such measures. We used cameras to monitor badger activity in 155 farmyards in south west England and Wales, and related variations in the presence and frequency of badger visits to farm characteristics. Badgers were recorded on camera in 40% of farmyards monitored. However, the frequency of visits was highly variable, with badgers recorded on >50% of nights in only 10% of farms. The presence of badgers in farmyards was positively associated with the density of badger setts, the number of feed stores and the number of cattle sheds, and negatively associated with the distance to the nearest active badger sett, the presence of a house/dwelling and the number of cattle housed on the farm. The frequency of visits was negatively associated with the distance to the nearest active badger sett and the number of cattle housed. Models predicted the presence/absence of badgers in farmyards with 73% accuracy (62% sensitivity, 81% specificity, using a cut off value of 0.265). Models could not distinguish between farms with low/high frequency of visits, although farms predicted as having badgers present typically had a higher frequency of visits than those that were not. We developed and present an interactive web based application: the Badger Farm Assessment Tool (BFAT), to allow users to enter the characteristics of a farm and generate a relative risk score describing the likelihood of badger visits.

Compounding effect of vitamin D3 diet, supplementation, and alcohol exposure on macrophage response to mycobacterium infection

Vitamin D₃ is known to be a key component in the defense against Mycobacterium tuberculosis (Mtb) infection through the regulation of cytokine and effector molecules. Conversely, alcohol exposure has been recognized as an immune dysregulator. Macrophages were extracted from D₃ deficient and sufficient diet mice and supplemented with D₃ or exposed to ethanol during ex vivo infection using M. bovis BCG, as a surrogate for Mtb. Results of our study indicate that while exogenous supplementation or alcohol exposure did alter immune response, in vivo diet was the greatest determinant of cytokine and effector molecule production. Alcohol exposure was found to profoundly dysregulate primary murine macrophages, with ethanol-exposed cells generally characterized as hyper- or hyporesponsive. Exogenous D₃ supplementation had a normative effect for diet deficient host, however supplementation was not sufficient to compensate for the effects of diet deficiency. Vitamin D₃ sufficient diet resulted in reduced cell cytotoxicity for the majority of time points. Results provide insight into the ramifications of both the individual and combined health risks of D₃ deficiency or alcohol exposure. Given the clinical relevance of D₃ deficiency and alcohol use comorbidities, outcomes of this study have implications in therapeutic approaches for the treatment of tuberculosis disease.

The Mycobacterium tuberculosis glycoprotein Rv1016c protein inhibits dendritic cell maturation, and impairs Th1 /Th17 responses during mycobacteria infection

The myobacterial factors and the associated mechanism by which Mycobacterium tuberculosis (Mtb) evades the host immune surveillance system remain widely unexplored. Here, we found that overexpressing Rv1016c, a mannosylated protein of M. tuberculosis in BCG (rBCG-Rv1016c) led to increased virulence of the recombined BCG in the severe-combined immunodeficient (SCID) mice model and to a loss of protective efficacy in a zebrafish-M. marinum model, compared to wild type BCG. Further investigations on the effects of rBCG-Rv1016c on the host innate immunity revealed that rBCG-Rv1016c decreased the production of cytokines IL-2, IL-12p70, TGF-β, IL-6 as well as of the co-stimulatory molecules CD80, CD86, MHC-I and MHC-II by the infected DCs. These effects were mimicked by rBCG-Rv1016cHis, which carried an extra 6-His tag at the C-terminus of Rv1016c. Relatively to BCG infected DCs, the rBCG-Rv1016c-infected DCs failed to polarize naïve T cells to Th1- and Th17-type cells to secret IFN-γ and IL-17. Additionally, T lymphocytes from BCG- infected mice showed significantly less proliferation and production of IFN-γ and IL-17. Similarly, rBCG-Rv1016c mice released a higher level of IL-10 in response to rBCG-Rv1016c stimulation than wild type BCG infected mice. Furthermore, DCs from TLR-2 knockout mice showed no reduction in IL-6, IL-12 p70 and TGF-β secretion in response to rBCG-Rv1016c infection, compared to DCs infected with BCG. We propose that Rv1016c interferes in differentiation of the DCs by targeting suppressor of cytokine signaling (SOCS) 1 and SOCS3 expression, which subsequently leads to the reduction in STAT-1 and STAT-6 phosphorylation. These findings open new perspectives regarding the immunosuppressive strategies adopted by Mtb to survive in the host.

Hydroalcoholic extract from Origanum vulgare induces a combined anti-mycobacterial and anti-inflammatory response in innate immune cells

In nature, many plants or their extracted compounds have been found to possess anti-inflammatory features and therapeutic properties against infectious as well as non-infectious diseases, including cancer. In this study, we analysed the immunomodulatory effects on innate immune cells of hydroalcoholic extract from Origanum vulgare L. ssp. hirtum (HyE-Ov), a plant traditionally known for its anti-oxidative properties. The effects of HyE-Ov were tested on human monocyte derived dendritic cells (DC), type-1 (M1) and type-2 macrophages (M2) infected with M. bovis Bacille Calmette-Guérin (BCG), used as a model of persistent intracellular bacterium. DC, M1 and M2 treated with HyE-Ov significantly enhanced their mycobactericidal activity, which was associated with phagosomal acidification in M1 and M2 and increase of phagosomal, but not mitochondrial ROS production in M1, M2, and DC. Treatment of BCG-infected DC with HyE-Ov significantly reduced TNF-α and IL-12 production and increased TGF-β synthesis. Finally, experiments were repeated using eight different HPLC fractions of HyE-Ov. Results showed that the capability to activate anti-microbial and anti-inflammatory response is shared by different fractions, suggesting that diverse bioactive molecules are present within the hydroalcoholic extract. Altogether, these results show that HyE-Ov promotes anti-mycobacterial innate immunity and limits inflammatory response in vitro and suggest that this plant extract may be exploitable as phytocomplex or nutraceutical for novel host-directed therapeutic approaches.

Comparative Study of the Molecular Basis of Pathogenicity of M. bovis Strains in a Mouse Model

It is widely accepted that different strains of Mycobacterium tuberculosis have variable degrees of pathogenicity and induce different immune responses in infected hosts. Similarly, different strains of Mycobacterium bovis have been identified but there is a lack of information regarding the degree of pathogenicity of these strains and their ability to provoke host immune responses. Therefore, in the current study, we used a mouse model to evaluate various factors involved in the severity of disease progression and the induction of immune responses by two strains of M. bovis isolated from cattle. Mice were infected with both strains of M. bovis at different colony-forming unit (CFU) via inhalation. Gross and histological findings revealed more severe lesions in the lung and spleen of mice infected with M. bovis N strain than those infected with M. bovis C68004 strain. In addition, high levels of interferon-γ (IFN-γ), interleukin-17 (IL-17), and IL-22 production were observed in the serum samples of mice infected with M. bovis N strain. Comparative genomic analysis showed the existence of 750 single nucleotide polymorphisms and 145 small insertions/deletions between the two strains. After matching with the Virulence Factors Database, mutations were found in 29 genes, which relate to 17 virulence factors. Moreover, we found an increased number of virulent factors in M. bovis N strain as compared to M. bovis C68004 strain. Taken together, our data reveal that variation in the level of pathogenicity is due to the mutation in the virulence factors of M. bovis N strain. Therefore, a better understanding of the mechanisms of mutation in the virulence factors will ultimately contribute to the development of new strategies for the control of M. bovis infection.

Bait uptake by wild badgers and its implications for oral vaccination against tuberculosis

The deployment of baits containing vaccines or toxins has been used successfully in the management of wildlife populations, including for disease control. Optimisation of deployment strategies seeks to maximise uptake by the targeted population whilst ensuring cost-effectiveness. Tuberculosis (TB) caused by infection with Mycobacterium bovis affects a broad range of mammalian hosts across the globe, including cattle, wildlife and humans. The control of TB in cattle in the UK and Republic of Ireland is hampered by persistent infection in European badgers (Meles meles). The present study aimed to determine the best strategy for maximising uptake of an oral vaccine by wild badgers, using a surrogate novel bait deployed at 40 badger social groups. Baits contained a blood-borne biomarker (Iophenoxic Acid, IPA) in order to measure consumption in badgers subsequently cage trapped at targeted setts. Evidence for the consumption of bait was found in 83% (199/240) of captured badgers. The probability that badgers had consumed at least one bait (IPA >10 μg ml-1) was significantly higher following deployment in spring than in summer. Lower uptake amongst social groups where more badgers were captured, suggested competition for baits. The probability of bait consumption was significantly higher at groups where main and outlier setts were provided with baits than at those where outliers were present but not baited. Badgers captured 10-14 days post bait feeding had significantly higher levels of bait uptake compared to those caught 24-28 days later. Uptake rates did not vary significantly in relation to badger age and whether bait was placed above ground or down setts. This study suggests that high levels of bait uptake can be achieved in wild badger populations and identifies factors influencing the potential success of different deployment strategies. The implications for the development of an oral badger vaccine are discussed.

Efficacy of parenteral vaccination against tuberculosis with heat-inactivated Mycobacterium bovis in experimentally challenged goats

Tuberculosis (TB) in animals is a re-emerging disease with a wide range of hosts that causes large economic losses in livestock. Goats are particularly susceptible to TB and, in endemic areas, vaccination may be a valuable measure to control the disease. The main aim of this study was to evaluate the efficacy of parenteral vaccination of goats with a heat-inactivated Mycobacterium bovis (HIMB) vaccine, and compare it to M. bovis Bacille Calmette–Guérin (BCG) vaccine. Twenty-four goat kids were divided in 3 groups as following: HIMB vaccinated group (n = 8), BCG vaccinated group (n = 8) and unvaccinated group (n = 8). Afterwards, goats were experimentally challenged with Mycobacterium caprae by the endobronchial route. Antigen specific interferon-γ release assays and serology were performed after vaccination and challenge. Pathological and bacteriological parameters were evaluated after necropsy at 9 weeks post-challenge (p.c.). HIMB vaccine showed similar levels of protection to BCG in terms of volume reduction of thoracic TB lesions, presence of extra-pulmonary lesions, as well as a slight reduction of bacterial load in pulmonary lymph nodes. Moreover, HIMB vaccine did not induce interferences on the interferon-γ release assay based on reagents previously developed to differentiate infected from BCG vaccinated individuals. The results indicate that HIMB is a suitable vaccine candidate for further larger-scale trials under field conditions in goats.

Development of a non-human primate BCG infection model for the evaluation of candidate tuberculosis vaccines

The lack of validated immunological correlates of protection makes tuberculosis vaccine development difficult and expensive. Using intradermal bacille Calmette-Guréin (BCG) as a surrogate for aerosol Mycobacterium tuberculosis (M.tb) in a controlled human infection model could facilitate vaccine development, but such a model requires preclinical validation. Non-human primates (NHPs) may provide the best model in which to do this. Cynomolgus and rhesus macaques were infected with BCG by intradermal injection. BCG was quantified from a skin biopsy of the infection site and from draining axillary lymph nodes, by culture on solid agar and quantitative polymerase chain reaction. BCG was detected up to 28 days post-infection, with higher amounts of BCG detected in lymph nodes after high dose compared to standard dose infection. Quantifying BCG from lymph nodes of cynomolgus macaques 14 days post-high dose infection showed a significant reduction in the amount of BCG detected in the BCG-vaccinated compared to BCG-naïve animals. Demonstrating a detectable vaccine effect in the lymph nodes of cynomolgus macaques, which is similar in magnitude to that seen in an aerosol M.tb infection model, provides support for proof-of-concept of an intradermal BCG infection model and evidence to support the further evaluation of a human BCG infection model.

Miliary pulmonary infection after BCG intravesical instillation: a rare, misdiagnosed and mistreated complication

Intravesical Bacillus Calmette-Guérin (BCG) immunotherapy decreases the progression risk of non-muscle-invasive bladder cancer, but potentially yields a broad spectrum of side effects. We report the case of a 73-year-old man affected by miliary pulmonary BCG infection, whose microbiological diagnosis was probably hindered by empiric fluoroquinolones, focusing on imaging and clinical work-up.

Modeling tuberculosis pathogenesis through ex vivo lung tissue infection

Tuberculosis (TB) is one of the top 10 causes of death worldwide. Several in vitro and in vivo experimental models have been used to study TB pathogenesis and induction of immune response during Mycobacterium tuberculosis infection. Precision cut lung tissue slices (PCLTS) is an experimental model, in which all the usual cell types of the organ are found, the tissue architecture and the interactions amongst the different cells are maintained. PCLTS in good physiological conditions, monitored by MTT assay and histology, were infected with either virulent Mycobacterium tuberculosis strain H37Rv or the TB vaccine strain Mycobacterium bovis BCG. Histological analysis showed that bacilli infecting lung tissue slices were observed in the alveolar septa, alveolar light spaces, near to type II pneumocytes, and inside macrophages. Mycobacterial infection of PCLTS induced TNF-α production, which is consistent with previous M. tuberculosis in vitro and in vivo studies. This is the first report of using PCLTS as a system to study M. tuberculosis infection. The PCLTS model provides a useful tool to evaluate the innate immune responses and other aspects during the early stages of mycobacterial infection.

Differences in pathogenicity of three animal isolates of Mycobacterium species in a mouse model

Animal mycobacterioses are among the most important zoonoses worldwide. These are generally caused by either Mycobacterium tuberculosis (MTB), M. bovis (MBO) or M. avium (MAV). To test the hypothesis that different species of pathogenic mycobacteria isolated from varied anatomic locations or animal species differ in virulence and pathogenicity, we performed experiments with three mycobacteria strains (NTSE-3(MTB), NTSE-4(MBO) and NTSE-5 (MAV)) obtained from animal species. Spoligotyping analysis was used to confirm both MTB and MBO strains while the MAV strain was confirmed by 16s rDNA sequencing. BALB/c mice were intranasally infected with the three strains at low and high CFU doses to evaluate variations in pathogenicity. Clinical and pathological parameters were assessed. Infected mice were euthanized at 80 days post-inoculation (dpi). Measures of lung and body weights indicated that the MBO infected group had higher mortality, more weight loss, higher bacterial burden and more severe lesions in lungs than the other two groups. Cytokine profiles showed higher levels of TNF-α for MBO versus MTB, while MAV had the highest amounts of IFN-β in vitro and in vivo. In vitro levels of other cytokines such as IL-1β, IL-10, IL-12, IL-17, and IFN-β showed that Th1 cells had the strongest response in MBO infected mice and that Th2 cells were inhibited. We found that the level of virulence among the three isolates decreased in the following order MBO>MTB>MAV.

Use of fecal volatile organic compound analysis to discriminate between non-vaccinated and BCG-Vaccinated cattle prior to and after Mycobacterium bovis challenge

Bovine tuberculosis is a zoonotic disease of global public health concern. Development of diagnostic tools to improve test accuracy and efficiency in domestic livestock and enable surveillance of wildlife reservoirs would improve disease management and eradication efforts. Use of volatile organic compound analysis in breath and fecal samples is being developed and optimized as a means to detect disease in humans and animals. In this study we demonstrate that VOCs present in fecal samples can be used to discriminate between non-vaccinated and BCG-vaccinated cattle prior to and after Mycobacterium bovis challenge.

Experimental Mycobacterium bovis infection in three white rhinoceroses (Ceratotherium simum): Susceptibility, clinical and anatomical pathology

Tuberculosis caused by Mycobacterium bovis is endemic in the African buffalo (Syncerus caffer) population in the Kruger National Park and other conservation areas in South Africa. The disease has been diagnosed in a total of 21 free ranging or semi-free ranging wildlife species in the country with highly variable presentations in terms of clinical signs as well as severity and distribution of tuberculous lesions. Most species are spillover or dead-end hosts without significant role in the epidemiology of the disease. White rhinoceroses (Ceratotherium simum) are translocated from the Kruger National Park in substantial numbers every year and a clear understanding of their risk to manifest overt tuberculosis disease and to serve as source of infection to other species is required. We report the findings of experimental infection of three white rhinoceroses with a moderately low dose of a virulent field isolate of Mycobacterium bovis. None of the animals developed clinical signs or disseminated disease. The susceptibility of the white rhinoceros to bovine tuberculosis was confirmed by successful experimental infection based on the ante mortem isolation of M. bovis from the respiratory tract of one rhinoceros, the presence of acid-fast organisms and necrotizing granulomatous lesions in the tracheobronchial lymph nodes and the detection of M. bovis genetic material by PCR in the lungs of two animals.

Exposure of Threatened Accipitridae to Mycobacterium bovis Calls for Active Surveillance

Anthropogenic activities have cumulatively led to the dramatic decline of world populations of vultures that currently face serious survival challenges in several regions of the world. In Portugal, the three resident species qualify as endangered and are under conservation efforts, mainly in the central east and south-east regions, where habitat protection and artificial feeding stations were implemented. Concurrently, the areas under protection are highly affected by tuberculosis (TB) in cattle and wild ungulates, whose potentially infected carcasses may naturally or artificially be used as feed by local vultures. In this work, we opportunistically surveyed populations of Eurasian griffon (Gyps fulvus) and Eurasian black vulture (Aegypius monachus) for the presence of Mycobacterium bovis. Nine pathogenic mycobacteria, including one M. bovis isolate, were cultured from the oropharynx of nine of the surveyed vultures (n = 55), sampled in recovery centres or in artificial feeding stations. Genotyping of the M. bovis strain indicated spoligotype SB0121, the most frequent type in Portugal, and a unique MIRU-VNTR profile that differed in two loci from the profiles of SB0121 bovine and deer strains from the same geographical area. The M. bovis-positive griffon exhibited poor clinical condition when admitted to the recovery centre; however, clinical evidence of TB was not present. Although the significance of M. bovis isolation in this vulture specimen could not be ascertained and despite the accepted notion that vultures are naturally resistant to microbial pathogens, the sanitary follow-up of Accipitridae vulture populations in TB-hotspot areas is essential to safeguard ongoing conservation efforts and also to evaluate the suitability of standing legislation on deliberate supplementary feeding schemes for menaced birds of prey.

The role of hydrophobicity in tuberculosis evolution and pathogenicity

The evolution of tubercle bacilli parallels a route from environmental Mycobacterium kansasii, through intermediate "Mycobacterium canettii", to the modern Mycobacterium tuberculosis complex. Cell envelope outer membrane lipids change systematically from hydrophilic lipooligosaccharides and phenolic glycolipids to hydrophobic phthiocerol dimycocerosates, di- and pentaacyl trehaloses and sulfoglycolipids. Such lipid changes point to a hydrophobic phenotype for M. tuberculosis sensu stricto. Using Congo Red staining and hexadecane-aqueous buffer partitioning, the hydrophobicity of rough morphology M. tuberculosis and Mycobacterium bovis strains was greater than smooth "M. canettii" and M. kansasii. Killed mycobacteria maintained differential hydrophobicity but defatted cells were similar, indicating that outer membrane lipids govern overall hydrophobicity. A rough M. tuberculosis H37Rv ΔpapA1 sulfoglycolipid-deficient mutant had significantly diminished Congo Red uptake though hexadecane-aqueous buffer partitioning was similar to H37Rv. An M. kansasii, ΔMKAN27435 partially lipooligosaccharide-deficient mutant absorbed marginally more Congo Red dye than the parent strain but was comparable in partition experiments. In evolving from ancestral mycobacteria, related to "M. canettii" and M. kansasii, modern M. tuberculosis probably became more hydrophobic by increasing the proportion of less polar lipids in the outer membrane. Importantly, such a change would enhance the capability for aerosol transmission, affecting virulence and pathogenicity.

Survivability of Mycobacterium bovis on salt and salt-mineral blocks fed to cattle

OBJECTIVE To determine the survivability of Mycobacterium bovis on salt and salt-mineral blocks in typical weather conditions in Michigan over two 12-day periods at the height of summer and winter. SAMPLE 4 salt (NaCl) and 4 salt-mineral blocks inoculated with pure cultures of a strain of M bovis currently circulating in Michigan livestock and wildlife. PROCEDURES In the summer and again in the winter, inoculated blocks were placed in secured outdoor facilities where equal numbers of each block type (2/type/season) were exposed to shade or sunlight. Samples were collected from randomly selected areas on the surface of each block beginning within 1 hour after placement (day 0) twice a day for the first 4 days and once a day from days 7 through 11. Bacterial culture of samples was performed to detect viable M bovis. RESULTS Depending on the exposure conditions, salt blocks yielded viable M bovis for up to 2 days after inoculation and salt-mineral blocks yielded viable M bovis for > 3 days. Survival time was greatest on salt-mineral blocks kept outdoors in the shade during the winter. The odds of recovering viable M bovis from salt-mineral block samples were 4.9 times as great during the winter (vs the summer) and 3.0 times as great with exposure to shade (vs sunlight). CONCLUSIONS AND CLINICAL RELEVANCE Results from this study indicated that salt and salt-mineral blocks should be considered potential sources of bovine tuberculosis when designing risk mitigation programs for cattle herds in areas with wildlife reservoirs of M bovis.

Altered Liver Proteoglycan/Glycosaminoglycan Structure as a Manifestation of Extracellular Matrix Remodeling upon BCG-induced Granulomatosis in Mice

Experimental BCG-induced granulomatosis in mice was used to study changes in the dynamics of individual liver proteoglycan components reflecting phasic extracellular matrix remodeling, determined by the host-parasite interaction and associated with granuloma development. In the early BCG-granulomatosis period, the increase in individual proteoglycan components promotes granuloma formation, providing conditions for mycobacteria adhesion to host cells, migration of phagocytic cells from circulation, and cell-cell interaction leading to granuloma development and fibrosis. Later, reduced reserve capacity of the extracellular matrix, development of interstitial fibrosis and granuloma fibrosis can lead to trophic shortage for cells within the granulomas, migration of macrophages out of them, and development of spontaneous necrosis and apoptosis typical of tuberculosis.

The genomics of mycobacteria

The species Mycobacterium bovis and Mycobacterium avium subspecies paratuberculosis are the causal agents, respectively, of tuberculosis and paratuberculosis in animals. Both mycobacteria, especially M. bovis, are also important to public health because they can infect humans. In recent years, this and the impact of tuberculosis and paratuberculosis on animal production have led to significant advances in knowledge about both pathogens and their host interactions. This article describes the contribution of genomics and functional genomics to studies of the evolution, virulence, epidemiology and diagnosis of both these pathogenic mycobacteria.

Zoonotic tuberculosis. A comprehensive ONE HEALTH approach

The objective of this report is to provide information on Mycobacterium tuberculosis complex infections in animals and in humans. Included is information on the susceptibility of different species as well as information on etiology, epidemiology, pathogenesis, diagnosis, prevention and control of this disease. The term One Health has been adopted to describe the unified human medical and veterinary interdisciplinary/multidisciplinary collaborative approach to zoonoses and will be critical for future endeavors in the control of the global TB epidemic. This unified paradigm is ideally suited for control of bovine TB and many other international public health and clinical health issues. Sharing resources and increasing interaction between public health and veterinary medical scientists can raise awareness of 'shared risk' of bovine TB between humans and animals and, in resource-limited situations, can maximize use of existing infrastructure and reduce unnecessary duplication of effort in disease control programs.

The variability and seasonality of the environmental reservoir of Mycobacterium bovis shed by wild European badgers

The incidence of Mycobacterium bovis, the causative agent of bovine tuberculosis, has been increasing in UK cattle herds resulting in substantial economic losses. The European badger (Meles meles) is implicated as a wildlife reservoir of infection. One likely route of transmission to cattle is through exposure to infected badger urine and faeces. The relative importance of the environment in transmission remains unknown, in part due to the lack of information on the distribution and magnitude of environmental reservoirs. Here we identify potential infection hotspots in the badger population and quantify the heterogeneity in bacterial load; with infected badgers shedding between 1 × 10(3)- 4 × 10(5) M. bovis cells g(-1) of faeces, creating a substantial and seasonally variable environmental reservoir. Our findings highlight the potential importance of monitoring environmental reservoirs of M. bovis which may constitute a component of disease spread that is currently overlooked and yet may be responsible for a proportion of transmission amongst badgers and onwards to cattle.

Multiphase contrast-enhanced magnetic resonance imaging features of Bacillus Calmette-Guérin-induced granulomatous prostatitis in five patients

OBJECTIVE

To evaluate the multiphase contrast-enhanced magnetic resonance (MR) imaging features of Bacillus Calmette-Guérin (BCG)-induced granulomatous prostatitis (GP).

MATERIALS AND METHODS

Magnetic resonance images obtained from five patients with histopathologically proven BCG-induced GP were retrospectively analyzed for tumor location, size, signal intensity on T2-weighted images (T2WI) and diffusion-weighted images (DWI), apparent diffusion coefficient (ADC) value, and appearance on gadolinium-enhanced multiphase images. MR imaging findings were compared with histopathological findings.

RESULTS

Bacillus Calmette-Guérin-induced GP (size range, 9-40 mm; mean, 21.2 mm) were identified in the peripheral zone in all patients. The T2WI showed lower signal intensity compared with the normal peripheral zone. The DWIs demonstrated high signal intensity and low ADC values (range, 0.44-0.68 × 10(-3) mm(2)/sec; mean, 0.56 × 10(-3) mm(2)/sec), which corresponded to GP. Gadolinium-enhanced multiphase MR imaging performed in five patients showed early and prolonged ring enhancement in all cases of GP. Granulomatous tissues with central caseation necrosis were identified histologically, which corresponded to ring enhancement and a central low intensity area on gadolinium-enhanced MR imaging. The findings on T2WI, DWI, and gadolinium-enhanced images became gradually obscured with time.

CONCLUSION

Bacillus Calmette-Guérin-induced GP demonstrates early and prolonged ring enhancement on gadolinium-enhanced MR imaging which might be a key finding to differentiate it from prostate cancer.

Clinical characteristics and needle aspiration management of Bacillus Calmette-Guérin lymphadenitis in children

OBJECTIVES

To describe characteristics of children developing Bacillus Calmette-Guérin (BCG) lymphadenitis, and to evaluate needle aspiration treatment.

METHODS

Children developing BCG lymphadenitis following BCG vaccination in Al-Rass General Hospital, Al-Rass, Saudi Arabia were prospectively studied from October 2008 to September 2013. Non-suppurative BCG lymphadenitis was conservatively managed, while suppurative lymphadenitis was treated by needle aspiration.

RESULTS

The mean (SD) age of children (n=23) was 4.1 (1.4) months, and symptoms duration was 2.08 (1.38) months. Fifteen (65.2%) children had suppurative, whereas 8 (34.8%) had non-suppurative lymphadenitis. Age, gender, birth weight, and duration of symptoms were not significantly different between children with suppurative and non-suppurative lymphadenitis (p>0.05). Children with suppurative adenitis had higher weight, and larger size of the involved lymph nodes compared with those with non-suppurative nodes (p=0.001). Most (91.3%) had axillary lesions; with a mean lymph node size of 3.2 cm. Abscesses were detected by ultrasound in 8 (80%). Non-suppurative lymphadenitis was conservatively managed, while suppurative was aspirated. The mean duration for resolution was 3.25 months. Lymph nodes aspirate were positive for acid and alcohol fast bacilli in 10 patients (66.6%), and 3 of them grew Staphylococcus aureus.

CONCLUSION

Bacillus Calmette-Guérin adenitis occurs in young children, mainly as unilocular suppurative left axillary group with a mean size of 3.2 cm. Needle aspiration is safe in treatment of suppurative lymphadenitis. Mycobacteria stained positive in most of the suppurative lesions. Excision is not needed.

[When will the new tuberculosis vaccine appear?]

The problem of tuberculosis prophylaxis remains actual for many countries of the world including Russia. The search of candidates for substitution of the only authorized BCG vaccine has been ongoing for some time, because it does not prevent reactivation of the causative agent in the latent stage and causes generalized BCG-infection in individuals with pronounced immune deficiency. In October 2013 in Lille at the European Congress "World Vaccine 2013" results of multi-year projects and trials of around 40 novel tuberculosis vaccine candidates were presented. The article contains a critical analysis of the materials presented at the congress. 12 vaccines have been developed or are being developed for priming. Among those a live VPM 1002 vaccine based on a genetically modified BCG Mycobacterium bovis (HLY+rBCG) strain and an attenuated vaccine based on Mycobacterium tuberculosis (att. MTB-MTBVAC) have passed phase II clinical trials. 17 candidates are being examined as booster vaccines, among those 6 vaccines have passed phase II clinical trials, and are presented by both modified M. bovis strains and partial proteins of M. tuberculosis. Characteristics of the 3 most perspective vaccines have been presented at the congress: VPM 1002, H &H56 and MVA85A. VPM 1002 is the vaccine closest to introduction. This is a live recombinant anti-tuberculosis vaccine based on the BCG strain, its DNA had genes partially deleted, that code synthesis of listeriolysin. The trials have shown that protective effectiveness of the vaccine is significantly higher than the parent BCG due to better induction of CD4+ and CD8+ cells, as well as IFN-γ, IL-18, 12 and other cytokines responsible for cell immunity function against M. tuberculosis.

Immune Activity of BCG Infected Mouse Macrophages Treated with a Novel Recombinant Mouse Lactoferrin

Lactoferrin has been investigated for its adjuvant action to boost the BCG vaccine. Previous studies demonstrated that lactoferrin (LF) enhanced efficacy of the Bacillus Calmette-Guérin (BCG) vaccine to protect mice against the virulent Erdman Mycobacterium tuberculosis challenge. The studies here investigate the hypothesis that a novel CHO-derived recombinant mouse LF can modify cytokine production and antigen presentation molecules on macrophages. The mouse LF (rmLF) was examined for effects on bone marrow derived macrophage (BMM) activities when cultured with BCG. Comparisons were made to CHO-derived recombinant human LF (rhLF). Inflammatory cytokine responses were investigated, as were antigen presentation and associated co-stimulatory molecules. Cytokine responses were subsequently measured when these cells were co-cultured with naïve or BCG sensitized CD4+ lymphocytes. While overall responses were similar between mouse, human, and bovine forms, the homologous rmLF treated infected BMMs showed unique activation patterns of cytokine production. These results indicate that species-specific LF can have different effects on mouse macrophages exposed to BCG, thus potentially affecting adjuvant activity when used in models of vaccination in mice.

Revaccination of cattle with bacille Calmette-Guérin two years after first vaccination when immunity has waned, boosted protection against challenge with Mycobacterium bovis

In both humans and animals, controversy exists concerning the duration of protection induced by BCG vaccine against tuberculosis (TB) and whether revaccination enhances protection. A long-term study was undertaken to determine whether BCG-vaccinated calves would be protected against challenge with Mycobacterium bovis 2½ years after vaccination and to determine the effect of revaccination after 2 years. Seventy-nine calves were divided into five groups (n = 15-17 calves/group) with four of the groups vaccinated subcutaneously with 105 CFU of BCG Danish at 2-4 weeks of age and the fifth group serving as non-vaccinated controls. Three of the four BCG-vaccinated groups were revaccinated 2 years after the initial vaccination. One BCG-vaccinated group was revaccinated with BCG. A second group was vaccinated subcutaneously with a TB protein vaccine consisting of biopolyester particles (Biobeads) displaying two mycobacterial proteins, ESAT-6 and Antigen 85A, mixed with an adjuvant. A third group was vaccinated with TB proteins from M. bovis culture filtrate, mixed with an adjuvant. Twenty-three weeks after the BCG revaccination, all animals were challenged endotracheally with virulent M. bovis and a further 13 weeks later, animals were killed and necropsied to determine protection against TB. The BCG-vaccinated animals produced positive tuberculin caudal fold intradermal (15 of 62 animals) and IFN-γ TB test responses (six of 62 animals) at 6 months after vaccination, but not at subsequent time-points compared to the non-vaccinated animals. Calves receiving a single vaccination with BCG vaccine 2½ years prior to challenge were not protected against TB, while those revaccinated with BCG 2 years after the initial vaccination displayed significant reductions in lung and pulmonary lymph node lesion scores compared to the non-vaccinated animals. In contrast, no reduction in lesion scores was observed in the animals revaccinated with the TB protein vaccines with their immune responses biased towards induction of antibody.

Non-tuberculous mycobacterial infections of veterinary relevance

Mycobacteria play an important role in human and animal health fields. We here examine the place of non tuberculous mycobacteria (NTM) infections in the veterinary context. Relevant aspects of a reference laboratory experience and a literature review are presented in this article. Importance is given both to productivity and to economic losses due to misdiagnosis with bovine tuberculosis and paratuberculosis. The impact NTM may have is relative to geographical location, ecology, husbandry, extent of surveillance programs and bovine tuberculosis and paratuberculosis prevalence. The role of the most relevant NTM in animal disease is summarized with a special focus on Mycobacterium avium subsp. paratuberculosis, given its role as causative agent of paratuberculosis, a disease with huge economic consequences for ruminant livestock.

Pulmonary infection with hypervirulent Mycobacteria reveals a crucial role for the P2X7 receptor in aggressive forms of tuberculosis

The purinergic P2X7 receptor (P2X7R) is a sensor of extracellular ATP, a damage-associated molecule that is released from necrotic cells and that induces pro-inflammatory cytokine production and cell death. To investigate whether the innate immune response to damage signals could contribute to the development of pulmonary necrotic lesions in severe forms of tuberculosis, disease progression was examined in C57BL/6 and P2X7R^−/− mice that were intratracheally infected with highly virulent mycobacterial strains (Mycobacterium tuberculosis strain 1471 of the Beijing genotype family and Mycobacterium bovis strain MP287/03). The low-dose infection of C57BL/6 mice with bacteria of these strains caused the rapid development of extensive granulomatous pneumonia with necrotic areas, intense bacillus dissemination and anticipated animal death. In contrast, in P2X7R^−/− mice, the lung pathology presented with moderate infiltrates of mononuclear leukocytes without visible signs of necrosis; the disease attenuation was accompanied by a delay in mortality. In vitro, the hypervirulent mycobacteria grew rapidly inside macrophages and induced death by a P2X7R-dependent mechanism that facilitated the release of bacilli. Furthermore, these bacteria were resistant to the protective mechanisms elicited in macrophages following extracellular ATP stimulation. Based on this study, we propose that the rapid intracellular growth of hypervirulent mycobacteria results in massive macrophage damage. The ATP released by damaged cells engages P2X7R and accelerates the necrotic death of infected macrophages and the release of bacilli. This vicious cycle exacerbates pneumonia and lung necrosis by promoting widespread cell destruction and bacillus dissemination. These findings suggest the use of drugs that have been designed to inhibit the P2X7R as a new therapeutic approach to treat the aggressive forms of tuberculosis.

Nearly 9 million new cases of tuberculosis and 1.3 million deaths are reported yearly worldwide. Most individuals infected with tubercle bacilli remain asymptomatic; however, some develop active tuberculosis due to the reactivation of latent infections. Progressive primary tuberculosis is an alternative form of the disease that mostly affects children and immunocompromised individuals. Extensive pneumonia, pulmonary necrosis and bacillus dissemination characterize some of the aggressive forms of tuberculosis. To investigate the molecular mechanisms that underlie severe disease progression, we used experimental models of relatively resistant C57BL/6 mice that were infected with highly virulent strains of Mycobacterium tuberculosis or Mycobacterium bovis. Two hypervirulent strains (Mtb strain 1471 and Mbv strain MP287/03) induced extensive pulmonary inflammation and necrosis in mice and promoted bacillus dissemination and animal death. We hypothesized that the innate immune response to endogenous damage signals from necrotic cells could aggravate the disease. We focused our study on the purinergic P2X7 receptor (P2X7R), a sensor of ATP that is released from necrotic cells and that induces pro-inflammatory cytokine production and cell death. Our data provide new insights into the pathogenesis of severe tuberculosis by showing that mice that lack P2X7R have attenuated disease with substantially reduced bacillus dissemination and lung inflammation without evidence of necrosis.

Cigarette smoke impairs cytokine responses and BCG containment in alveolar macrophages

BACKGROUND

There is a strong epidemiological link between smoking and tuberculosis (TB), but the association is confounded by socioeconomic and other factors. A direct relationship between cigarette smoke and poor treatment-related outcomes in patients with TB is therefore questionable. We investigated whether constituents of tobacco smoke impair mycobacterial host immune responses in vitro.

METHODOLOGY

Preparation of a cigarette smoke extract (CSE) from Marlboro Red cigarettes was standardised and reproducibility verified by mass spectroscopy. Macrophages were derived from peripheral blood monocytes (MDM) and alveolar macrophages from bronchoalveolar lavage fluid from healthy non-smoking volunteers. Mycobacterial uptake (flow cytometric detection of fluorescence using green fluorescent protein-labelled BCG), cytokine responses (ELISA) and mycobacterial containment (colony forming units) was evaluated in both macrophage populations with and without co-culture with CSE, nicotine and a nicotine receptor blocker.

RESULTS

Cigarette smoke failed to impair the uptake of mycobacteria by monocyte-derived or alveolar macrophages. CSE (vs no CSE) reduced the mean (SD) BCG-driven macrophage (MDM) interferon γ (IFN-γ), tumour necrosis factor α (TNF-α) and interleukin 10 (IL-10) responses by 56.4 (18.6)%, 67.0 (33.4)% and 77.7 (27.7)%, respectively (p<0.001). Nicotine alone impaired IL-10 and TNF-α production by 48.8 (37)% and 49 (50)%, respectively (p<0.05) through an α-7 nicotine receptor-independent mechanism. In 5-day cultures, CSE impaired mycobacterial (BCG) containment in both monocyte-derived and alveolar macrophages.

CONCLUSIONS

Cigarette smoke attenuates effector cytokine responses and impairs mycobacterial containment within infected human macrophages derived from the peripheral blood and alveolar compartments, thus supporting the hypothesis that cigarette smoke subverts mycobacteria-related immunity.

(1)H-NMR spectroscopy revealed Mycobacterium tuberculosis caused abnormal serum metabolic profile of cattle

To re-evaluate virulence of Mycobacterium tuberculosis (M. tb) in cattle, we experimentally infected calves with M. tb andMycobacterium bovisvia intratracheal injection at a dose of 2.0×10⁷ CFU and observed the animals for 33 weeks. The intradermal tuberculin test and IFN-γin vitro release assay showed that both M. tb and M. bovis induced similar responses. Immunohistochemical staining of pulmonary lymph nodes indicated that the antigen MPB83 of both M. tb and M. bovis were similarly distributed in the tissue samples. Histological examinations showed all of the infected groups exhibited neutrophil infiltration to similar extents. Although the infected cattle did not develop granulomatous inflammation, the metabolic profiles changed significantly, which were characterized by a change in energy production pathways and increased concentrations of N-acetyl glycoproteins. Glycolysis was induced in the infected cattle by decreased glucose and increased lactate content, and enhanced fatty acid β-oxidation was induced by decreased TG content, and decreased gluconeogenesis indicated by the decreased concentration of glucogenic and ketogenic amino acids promoted utilization of substances other than glucose as energy sources. In addition, an increase in acute phase reactive serum glycoproteins, together with neutrophil infiltration and increased of IL-1β production indicated an early inflammatory response before granuloma formation. In conclusion, this study indicated that both M. tb and M.bovis were virulent to cattle. Therefore, it is likely that cattle with M. tb infections would be critical to tuberculosis transmission from cattle to humans. Nuclear magnetic resonance was demonstrated to be an efficient method to systematically evaluate M. tb and M. bovi sinfection in cattle.

Field-isolated genotypes of Mycobacterium bovis vary in virulence and influence case pathology but do not affect outbreak size

Strains of many infectious agents differ in fundamental epidemiological parameters including transmissibility, virulence and pathology. We investigated whether genotypes of Mycobacterium bovis (the causative agent of bovine tuberculosis, bTB) differ significantly in transmissibility and virulence, combining data from a nine-year survey of the genetic structure of the M. bovis population in Northern Ireland with detailed records of the cattle population during the same period. We used the size of herd breakdowns as a proxy measure of transmissibility and the proportion of skin test positive animals (reactors) that were visibly lesioned as a measure of virulence. Average breakdown size increased with herd size and varied depending on the manner of detection (routine herd testing or tracing of infectious contacts) but we found no significant variation among M. bovis genotypes in breakdown size once these factors had been accounted for. However breakdowns due to some genotypes had a greater proportion of lesioned reactors than others, indicating that there may be variation in virulence among genotypes. These findings indicate that the current bTB control programme may be detecting infected herds sufficiently quickly so that differences in virulence are not manifested in terms of outbreak sizes. We also investigated whether pathology of infected cattle varied according to M. bovis genotype, analysing the distribution of lesions recorded at post mortem inspection. We concentrated on the proportion of cases lesioned in the lower respiratory tract, which can indicate the relative importance of the respiratory and alimentary routes of infection. The distribution of lesions varied among genotypes and with cattle age and there were also subtle differences among breeds. Age and breed differences may be related to differences in susceptibility and husbandry, but reasons for variation in lesion distribution among genotypes require further investigation.

Experimental aerosol Mycobacterium bovis model of infection in goats

The use of animal models is essential in testing the efficacy for novel therapies against tuberculosis (TB). Calves and non-human primates are examples of large animal models currently used to test TB vaccine efficacy but these animals are difficult and very expensive to house under high containment conditions. The goat may represent an effective but less expensive alternative for testing prototype vaccines against TB. Goats are susceptible to Mycobacterium bovis, Mycobacterium caprae and Mycobacterium tuberculosis infection. Aerosolized bacteria are the most common source of natural infection in humans and the primary site of natural infection is the respiratory tract. We developed a simple procedure for infecting goats with M. bovis by aerosol exposure. After 8 and 12 weeks of infection the goats were euthanized, post-mortem analysis was performed, and all exposed animals presented TB compatible lesions in the lung and associated lymph nodes. Selected lung lesions and respiratory lymph nodes were evaluated and cultured for bacteriological and histological analysis. The present work shows a reliable new animal model of aerosol infection to be used in the understanding of TB disease and development of new therapies.

Prevalence of latent and active tuberculosis among dairy farm workers exposed to cattle infected by Mycobacterium bovis

BACKGROUND

Human tuberculosis caused by M. bovis is a zoonosis presently considered sporadic in developed countries, but remains a poorly studied problem in low and middle resource countries. The disease in humans is mainly attributed to unpasteurized dairy products consumption. However, transmission due to exposure of humans to infected animals has been also recognized. The prevalence of tuberculosis infection and associated risk factors have been insufficiently characterized among dairy farm workers (DFW) exposed in settings with poor control of bovine tuberculosis.

METHODOLOGY/PRINCIPAL FINDINGS

Tuberculin skin test (TST) and Interferon-gamma release assay (IGRA) were administered to 311 dairy farm and abattoir workers and their household contacts linked to a dairy production and livestock facility in Mexico. Sputa of individuals with respiratory symptoms and samples from routine cattle necropsies were cultured for M. bovis and resulting spoligotypes were compared. The overall prevalence of latent tuberculosis infection (LTBI) was 76.2% (95% CI, 71.4-80.9%) by TST and 58.5% (95% CI, 53.0-64.0%) by IGRA. Occupational exposure was associated to TST (OR 2.72; 95% CI, 1.31-5.64) and IGRA (OR 2.38; 95% CI, 1.31-4.30) adjusting for relevant variables. Two subjects were diagnosed with pulmonary tuberculosis, both caused by M. bovis. In one case, the spoligotype was identical to a strain isolated from bovines.

CONCLUSIONS

We documented a high prevalence of latent and pulmonary TB among workers exposed to cattle infected with M. bovis, and increased risk among those occupationally exposed in non-ventilated spaces. Interspecies transmission is frequent and represents an occupational hazard in this setting.

[The characteristics of production of cytokines in patients with tuberculosis of lungs]

The sample of 36 patients with primarily diagnosed mostly infiltrative tuberculosis of lungs was used to investigate the characteristics of spontaneous and stimulated by specific antigens production of cytokines FNO-alpha, IFN-beta, IL-8 playing the most significant role in pathogenesis of tuberculosis. The production of FNO-alpha and IFN-gamma was analyzed in the culture of peripheral mononuclear cells using antigen M. bovis (BCG). The cytokines IFN-gamma and IL-8 were analyzed in the cultures of whole heparinized blood using antigens H37Rv and ESAT-6. The significant inhibition of stimulated by antigens production of FNO-alpha and IFN-gamma in patients with severe, destructive and complicated forms of tuberculosis as compared with to patients with limited and favorably developing tuberculosis. The differences in production of lL-8 in patients with different degree of severity of tuberculosis process are not revealed.

Asymptomatic cattle naturally infected with Mycobacterium bovis present exacerbated tissue pathology and bacterial dissemination

Rational discovery of novel immunodiagnostic and vaccine candidate antigens to control bovine tuberculosis (bTB) requires knowledge of disease immunopathogenesis. However, there remains a paucity of information on the Mycobacterium bovis-host immune interactions during the natural infection. Analysis of 247 naturally PPD+ M. bovis-infected cattle revealed that 92% (n = 228) of these animals were found to display no clinical signs, but presented severe as well as disseminated bTB-lesions at post-mortem examination. Moreover, dissemination of bTB-lesions positively correlated with both pathology severity score (Spearman r = 0.48; p<0.0001) and viable tissue bacterial loads (Spearman r = 0.58; p = 0.0001). Additionally, granuloma encapsulation negatively correlated with M. bovis growth as well as pathology severity, suggesting that encapsulation is an effective mechanism to control bacterial proliferation during natural infection. Moreover, multinucleated giant cell numbers were found to negatively correlate with bacterial counts (Spearman r = 0.25; p = 0.03) in lung granulomas. In contrast, neutrophil numbers in the granuloma were associated with increased M. bovis proliferation (Spearman r = 0.27; p = 0.021). Together, our findings suggest that encapsulation and multinucleated giant cells control M. bovis viability, whereas neutrophils may serve as a cellular biomarker of bacterial proliferation during natural infection. These data integrate host granuloma responses with mycobacterial dissemination and could provide useful immunopathological-based biomarkers of disease severity in natural infection with M. bovis, an important cattle pathogen.

Host-pathogen specificity in tuberculosis

The host response to mycobacterial infection including tuberculosis depends on genetically controlled host and bacterial factors and their interaction. A largely unknown aspect of this interaction is whether disease results from an additive and independent effect of host and pathogen or from specific host-pathogen combinations. The preferential association of specific mycobacterial strains with specific ethnic groups provided tentative evidence in favor of host-pathogen specificity in tuberculosis and is consistent with the hypothesis of host-mycobacterial co-adaptation. Substantial evidence for specificity has now been provided by animal models and human case-control association studies. These studies indicate that differences in the host response to infection are at least in part due to specific combinations of host genetic factors and genetic and phenotypic characteristics of the infecting mycobacterial strain.

Direction of association between bite wounds and Mycobacterium bovis infection in badgers: implications for transmission

Background

Badgers are involved in the transmission to cattle of bovine tuberculosis (TB), a serious problem for the UK farming industry. Cross-sectional studies have shown an association between bite wounds and TB infection in badgers which may have implications for M. bovis transmission and control, although the sequence of these two events is unclear. Transmission during aggressive encounters could potentially reduce the effectiveness of policies which increase the average range of a badger and thus its opportunities for interaction with other social groups.

Methods

Data were obtained on badgers captured during a long term study at Woodchester Park, UK (1998–2006). Many badgers had multiple observations. At each observation, the badger was assigned a “state” depending on presence of bite wounds and/or TB infection. Hence each badger had a “transition” from the previous state to the current state. We calculated the numbers of each type of transition and the time spent in each state. Transition rates were calculated for each transition category, dividing the number of such transitions by the total time at risk. We compared the rate of bite wound acquisition in infected badgers with that for uninfected badgers and the rate of positive M.bovis test results in bitten badgers with that in unbitten badgers.

Results

The rate of bite wound acquisition in infected badgers (0.291 per year) was 2.09 (95% CI: 1.41, 3.08) times that in uninfected badgers (0.139 per year). The rate of positive M.bovis test results in bitten badgers (0.097 per year) was 2.45 (95% CI: 1.29, 4.65) times that in unbitten badgers (0.040 per year).

Conclusions

We found strong evidence of both potential sequences of events consistent with transmission via bite wounds and distinctive behaviour in infected badgers. The complex relationship between behaviour and infection must be considered when planning TB control strategies.