Analysis of the Diversity and Functional Potential of Bacterial Communities in Tuberculomas.

The dynamics of lung microbiota in tuberculosis remains poorly understood. Sequencing of variable regions of the 16S rRNA gene from surgically excised tuberculosis foci and biopsy specimens of normal lung tissue allowed characterization of the diversity and predictive potential of bacterial communities. Taxonomic diversity indices attested to differences in the structure of microbial communities between "healthy" lungs and tuberculomas. The microbial composition of "healthy" lungs varied in taxonomic diversity and was presented by both gram-positive and gram-negative bacteria with sufficiently similar metabolic potential. The microbiota of the examined tuberculomas consisted of Mycobacterium tuberculosis in 99.9% of cases. A significant part of the metabolic pathways predicted by PICRUSt2 included cholesterol catabolism, sulfate assimilation, and various pathways for the biosynthesis of cell wall components.

The C terminus of the mycobacterium ESX-1 secretion system substrate ESAT-6 is required for phagosomal membrane damage and virulence.

SignificanceTuberculosis (TB), an ancient disease of humanity, continues to be a major cause of worldwide death. The causative agent of TB, Mycobacterium tuberculosis, and its close pathogenic relative Mycobacterium marinum, initially infect, evade, and exploit macrophages, a major host defense against invading pathogens. Within macrophages, mycobacteria reside within host membrane-bound compartments called phagosomes. Mycobacterium-induced damage of the phagosomal membranes is integral to pathogenesis, and this activity has been attributed to the specialized mycobacterial secretion system ESX-1, and particularly to ESAT-6, its major secreted protein. Here, we show that the integrity of the unstructured ESAT-6 C terminus is required for macrophage phagosomal damage, granuloma formation, and virulence.

Resolution of Large Choroidal Tuberculoma following Monotherapy with Intravitreal Ranibizumab.

Background: Ocular tuberculosis can have protean manifestations. Anti-tubercular therapy (ATT) and oral steroids are employed in the management of this condition. There is evidence in the literature which has highlighted the use of intravitreal anti-vascular endothelial growth factor drugs as an adjunct to systemic therapy.Report of the Case: A 44-year-old male presented with a decrease of vision in the right eye was diagnosed choroidal tuberculoma with massive exudation and subretinal fluid. The patient was treated with intravitreal ranibizumab injection. The lesion regressed completely within 6 weeks without any additional systemic corticosteroids and ATT without any recurrence over 6 months during follow-up.Conclusions: Ranibizumab monotherapy may lead in complete regression of vascularized tubercular choroidal granulomas without the need of adjunctive ATT and corticosteroids. After intravitreal injection of ranibizumab, the lesion may be observed for regression over several weeks.

Spatial and temporal localization of immune transcripts defines hallmarks and diversity in the tuberculosis granuloma.

Granulomas are the pathological hallmark of tuberculosis (TB) and the niche where bacilli can grow and disseminate or the immunological microenvironment in which host cells interact to prevent bacterial dissemination. Here we show 34 immune transcripts align to the morphology of lung sections from Mycobacterium tuberculosis-infected mice at cellular resolution. Colocalizing transcript networks at <10 µm in C57BL/6 mouse granulomas increase complexity with time after infection. B-cell clusters develop late after infection. Transcripts from activated macrophages are enriched at subcellular distances from M. tuberculosis. Encapsulated C3HeB/FeJ granulomas show necrotic centers with transcripts associated with immunosuppression (Foxp3, Il10), whereas those in the granuloma rims associate with activated T cells and macrophages. We see highly diverse networks with common interactors in similar lesions. Different immune landscapes of M. tuberculosis granulomas depending on the time after infection, the histopathological features of the lesion, and the proximity to bacteria are here defined.

Cyclopropane Modification of Trehalose Dimycolate Drives Granuloma Angiogenesis and Mycobacterial Growth through Vegf Signaling.

Mycobacterial infection leads to the formation of characteristic immune aggregates called granulomas, a process accompanied by dramatic remodeling of the host vasculature. As granuloma angiogenesis favors the infecting mycobacteria, it may be actively promoted by bacterial determinants during infection. Using Mycobacterium marinum-infected zebrafish as a model, we identify the enzyme proximal cyclopropane synthase of alpha-mycolates (PcaA) as an important bacterial determinant of granuloma-associated angiogenesis. cis-Cyclopropanation of mycobacterial mycolic acids by pcaA drives the activation of host Vegf signaling within granuloma macrophages. Cyclopropanation of the mycobacterial cell wall glycolipid trehalose dimycolate is both required and sufficient to induce robust host angiogenesis. Inducible genetic inhibition of angiogenesis and Vegf signaling during granuloma formation results in bacterial growth deficits. Together, these data reveal a mechanism by which PcaA-mediated cis-cyclopropanation of mycolic acids promotes bacterial growth and dissemination in vivo by eliciting granuloma vascularization and suggest potential approaches for host-directed therapies.

Use of TBAg/PHA ratio in distinguishing tuberculoma from cancer in solitary pulmonary nodule or mass.

INTRODUCTION: Differentiation of tuberculoma from cancer in solitary pulmonary nodule or mass still remains a major challenge in diagnostic laboratories. OBJECTIVES: The objective of this study is to determine the performance of T-SPOT.TB assay in discriminating these 2 diseases. METHODS: We prospectively enrolled 331 patients with a solitary pulmonary nodule or mass on computed tomography scans. Conventional tests and T-SPOT.TB assay were simultaneously performed in all participants. RESULTS: Our results showed that the performance of directly using T-SPOT.TB results in distinguishing tuberculoma from cancer in solitary pulmonary nodule or mass was not satisfactory because of moderate sensitivity and specificity. However, a further calculation of the ratio of TB-specific antigen (TBAg) to phytohemagglutinin (PHA) (TBAg/PHA ratio) of T-SPOT.TB assay may lead to improvement in distinguishing these 2 diseases. If using the threshold value of 0.236, the sensitivity and specificity of the TBAg/PHA ratio in distinguishing tuberculoma from cancer in solitary pulmonary nodule or mass were, respectively, 80.6% and 93.3%. The area under the curve (AUC) of the receiver operating characteristic curve was 0.921 (95% confidence interval, 0.875-0.967). Furthermore, the TBAg/PHA ratio may also be used to distinguish tuberculoma from other benign diseases (AUC: 0.909, sensitivity: 85.07%, specificity: 90%). CONCLUSIONS: Calculation of the TBAg/PHA ratio might provide a useful non-invasive tool for distinguishing tuberculoma from cancer in patients with a solitary pulmonary nodule or mass in TB-endemic countries.

Spinal intramedullary tuberculoma following pulmonary tuberculosis: A case report and literature review.

RATIONALE: Spinal intramedullary tuberculoma (IMTB) is a rare disease that accounts for 1 to 2/100,000 patients with tuberculosis. We presented a case with pulmonary tuberculosis and concurrent IMTB at C3 to C5 level and reviewed the recent case series and discussed the diagnosis, treatment, and outcome. PATIENT CONCERNS: A 33-year-old male had concurrent pulmonary TB and IMTB at the C3 to C5 level. He had quadriplegia (muscle power 0 at 4 limbs) and sensory loss below C5 level. He also had incontinence, anal tone loss, and paradoxical respiratory pattern. DIAGNOSIS: Spinal magnetic resonance imaging (MRI) showed a 25 11mm intramedullary lesion at C3/C4 level. Under the impression of IMTB, he underwent surgery. INTERVENTION: We performed C3 to C5 laminectomy and en bloc removal of the tumor. The patient kept receiving anti-TB medications after the surgery. OUTCOME: His 4 limbs muscle power had improved but could not be liberated from the endotracheal tube, so tracheostomy was performed. Muscle power gradually increased to 3 points in his upper limbs and to 2 points in his lower limbs. Sensation in his 4 limbs gradually improved as well. LESSONS: IMTB is a rare disease that should be treated with a combination of medication and surgery. For patients with prominent spinal cord compression and neurological symptoms, early operation to remove the tumor is necessary.

Clinical and cytological features in diagnosis of peripheral tubercular lymphadenitis - A hospital-based study from central India.

BACKGROUND: Tuberculosis lymphadenitis is difficult to diagnose clinically, and often the laboratory confirmation is not available in resource-poor countries. We describe here the symptoms, clinical characteristics, and results of cytological analysis in peripheral tuberculous lymphadenitis patients. METHODS: One hundred and fifty-six patients with peripheral lymph node for cytological evaluation presenting to Department of Pathology, Acharya Vinoba Bhave Rural Hospital, Wardha, India were included in this study. RESULTS: Sixty-nine cases were tuberculous lymphadenitis, with female to male ratio of 1.3:1. One or more constitutional symptoms were present in 59.4% of patients, with 89.9% of lymph nodes ≥2×2cm and the most common site of involvement was cervical lymph node (70.3%). The lymph nodes were multiple (85.5%), either discrete or matted. Cytomorphologically, hemorrhagic aspirate was observed in 29 cases, well-formed epithelioid cell granuloma with caseous necrosis was seen in 34 cases, and Zeihl Neelsen staining was positive in 45 cases. Correlation between character of aspirate and cytomorphological pattern was found highly significant. CONCLUSION: These data suggest that constitutional symptoms and clinical and cytological features help in diagnosing cases of peripheral tubercular lymphadenitis and also open new frontiers to further research that affects the cytological features of these cases.

Bioengineered 3D Models for Studying Human Cell-Tuberculosis Interactions.

In vivo animal models have intrinsic limitations for studying relationships between tuberculosis and its host and there is a need for alternative, in vitro cellular models. A microsphere-based 3D in vitro culture system of Mycobacterium tuberculosis-infected human blood mononuclear cells was reported to address specific aspects of host-pathogen interactions.

[Interlaboratory test: Isolation of Mycobacterium bovis from granulomatous lesions in bovine]. / Ensayo interlaboratorio: aislamiento de Mycobacterium bovis a partir de lesiones granulomatosas en bovinos.

Mycobacterium bovis is the causative agent of bovine tuberculosis. The diagnostic laboratory confirmation is made through bacterial isolation. The aim of interlaboratory tests is to assess the performance of each participant in comparison with other of similar capacities. The test objective was to determine the efficiency of isolation of M. bovis. Four laboratories were part of the test and processed 25 blind tissue samples from granulomatous lesions and with previous M. bovis isolation. The laboratory that had the highest proportion of isolates was A (68%), followed by C (60%) and then B and D (both with 52%). The greatest concordance was observed between B-D and B-C laboratories (68%). The differences could be due to specific factors in each laboratory procedures. This type of interlaboratory tests highlights errors in the bacteriology and identifies critical points in the process to detect M. bovis accurately.

Mycobacterium tuberculosis: Manipulator of Protective Immunity.

Mycobacterium tuberculosis (MTB) is one of the most successful pathogens in human history and remains a global health challenge. MTB has evolved a plethora of strategies to evade the immune response sufficiently to survive within the macrophage in a bacterial-immunological equilibrium, yet causes sufficient immunopathology to facilitate its transmission. This review highlights MTB as the driver of disease pathogenesis and presents evidence of the mechanisms by which MTB manipulates the protective immune response into a pathological productive infection.

Modeling nanoparticle delivery of TB drugs to granulomas.

Tuberculosis, which typically presents as a pulmonary disease, has a complex pathology. The primary site of infection, the Ghon focus, recruits immune cells and a granuloma forms. At earlier stages the granuloma is still vascularized, offering the best opportunity for drug treatment. In the more progressive state blood flow is reduced and a distinct caseous structure develops. Effective delivery of drugs to bacilli in the core of the granuloma becomes very difficult. It is perceivable that granuloma cores could create conditions where bacilli persist and develop resistance. In this study we analyze drug delivery to granulomas by means of a nanoparticle delivery system. The model consists of two parts; the overall distribution of the nanoparticles is described by a simple circulatory model and this result is used in the second part, focusing on transport in a capillary lined with macrophages. Nanoparticles enter the macrophages where they are metabolized and the drugs are released. The model reveals significant differences in drug concentrations between the plasma and macrophages. Based on the results of the model, strategies for improved drug delivery are proposed.

Importance of contrast-enhanced fluid-attenuated inversion recovery imaging to detect paradoxical expansion of tuberculoma.

Tuberculosis is a significant public health problem that continues to be a major cause of morbidity and mortality worldwide. Tuberculous meningoencephalitis (TM) is the most common extrapulmonary lesion in tuberculosis. A 41-year-old female was thought to have TM. Tests to confirm the TM diagnosis were initially negative, including tuberculosis PCR and adenosine deaminase level in serum and cerebrospinal fluid (CSF). Anti-tuberculous medication and intravenous steroids were administered to her on the basis of brain imaging and lactate dehydrogenase electrophoresis in CSF, suggestive of the diagnosis of TM. Her neurological problems improved rapidly following treatment. Serologic and CSF markers were positive in PCR and culture after 60 days. Radiological findings are often nonspecific and TM is difficult to diagnose without an increased index of suspicion. The detection of paradoxical expansion of tuberculoma is very important in the maintenance of medication. Magnetic resonance imaging was used to detect paradoxical expansion of the tuberculoma using various methods, such as contrast-enhanced fluid-attenuated inversion recovery (CE-FLAIR) imaging. CE-FLAIR imaging conspicuously showed paradoxical expansion of the tuberculoma. If patients present with clear meningitis, without any identified pathogen, there is a need to constantly and scrupulously check for TM, including with the use of CE-FLAIR brain imaging.

Ruptured mycobacterial aneurysm of the carotid artery.

Mycotic aneurysms resulting from intravesical bacillus Calmette-Guérin (BCG) treatment are exceptionally rare. We report on the case of a 73-year-old man who underwent intravesical therapy of BCG for bladder carcinoma and developed a right neck mass. A carotid pseudoaneurysm within a fibrotic mass was noted on surgical exploration. Radical resection was performed followed by a polytetrafluoroethylene interposition graft. Final pathology revealed necrotizing granulomas and multinucleated giant cells concerning for tuberculoma. Intravesicular BCG immunotherapy is an accepted treatment for patients with urothelial carcinoma. Carotid aneurysms are exceptionally rare in this setting and should prompt evaluation for systemic tuberculoid dissemination.

Thrombocytosis is associated with Mycobacterium tuberculosis infection and positive acid-fast stains in granulomas.

Mycobacterium tuberculosis infection is associated with thrombocytosis. We sought to determine if this information might be valuable in evaluating granulomas using acid-fast stains (AFS). Fifty-eight patients with culture-confirmed M tuberculosis infection were compared with 75 patients with atypical mycobacterial infection and 48 patients negative for mycobacteria. Thrombocytosis (platelet count >360 × 10(3)/µL [360 × 10(9)/L]) was significantly more common in patients with M tuberculosis (50%) than those with either atypical mycobacterial infection (12%) or negative for mycobacteria (4%, P < .001 for each). In 67 patients, histologic evaluation of tissue samples showed granulomatous inflammation; 37 (55%) had positive AFS results. Of 19 patients with thrombocytosis, 16 (84%) had a positive AFS result compared with 21 (44%) of 48 without thrombocytosis (P = .003). Fifteen of 16 M tuberculosis cases with thrombocytosis had positive AFS findings on histologic evaluation; the single negative case had a platelet count of 362 × 10(3)/µL (362 × 10(9)/L). However, 3 of these cases of positive results on staining were initially diagnosed as negative and only recognized as positive on review. We conclude that patients whose specimens were sent for mycobacterial culture and thrombocytosis had an increased risk for M tuberculosis. Patients with granulomas and thrombocytosis are more likely to have a positive AFS result usually showing M tuberculosis. Finally, patients with initially negative AFS results and thrombocytosis deserve to have additional evaluation of the AFS specimens.

Looking within the zebrafish to understand the tuberculous granuloma.

Tuberculosis is characterized by the formation of complex immune cell aggregates called granulomas, which for nearly a century have been viewed as critical host-beneficial structures to restrict bacterial growth and spread. A different view has now emerged from real-time visualization of granuloma formation and its consequences in the optically transparent and genetically tractable zebrafish larva. Pathogenic mycobacteria have developed mechanisms to use host granulomas for their expansion and dissemination, at least during the innate phases of infection. Host processes that are intended to be beneficial-death of infected macrophages and their subsequent phagocytosis by macrophages that are newly recruited to the growing granuloma-are harnessed by mycobacteria for their own benefit. Mycobacteria can also render the granuloma a safe-haven in the more advanced stages of infection. An understanding of the host and bacterial pathways involved in tuberculous granuloma formation may suggest new ways to combat mycobacterial infection.

Primary musculoskeletal mycobacterium infection with large cystic masses after total hip arthroplasty.

Primary mycobacterial infections in the musculoskeletal system are rare with a limited number of published case reports. This report describes a case involving a primary musculoskeletal tuberculous abscess. A 62-year-old male patient who had a right total hip arthroplasty performed 8 years earlier, using metal-on-metal articulation presented with a 1-year history of non-tender masses on his right thigh. Initially, it was assumed he had metallosis. Intraoperatively, an incision into the mass was conducted which resulted in draining of a whitish-grey pus like fluid. A diagnosis of tuberculosis was confirmed with both microscopic and histological examination. The patient was treated over a course of six months with an anti-tuberculosis medication regimen following the confirmation of a solitary soft tissue tuberculosis infection. At the 24 month follow-up, the patient was asymptomatic with no relapse of the mass.