Coinfection of Mycobacterial diseases

Although both mycobacterial infections are endemic in developing countries, the coinfection has hardly been reported in the last decade. The combined National TB & Leprosy Control Programme of Bangladesh came into effect in 1994. Though the Elimination of Leprosy (<1 case / 10,000 population) was achieved nationally in 1998, Bangladesh is still endemic for Tuberculosis. A 10 years cohort study was conducted in six districts of the Northern part of Bangladesh, covered by the Damien Foundation. This cohort consisted of a total of 4,788 leprosy cases registered from 2007 to 2016. Reviewing the records of all these cases, 25 (0.52%) patients were identified as having coinfection with Tuberculosis & Leprosy. All cases were coinfected with smear positive pulmonary TB. This study concludes that duel infection with mycobacteria is uncommon. Early diagnosis is very important for better outcomes of both diseases. CBMJ 2020 July: Vol. 09 No. 02 P: 39-41

Host Immune-Metabolic Adaptations Upon Mycobacterial Infections and Associated Co-Morbidities

Mycobacterial diseases are a major public health challenge. Their causative agents include, in order of impact, members of the Mycobacterium tuberculosis complex (causing tuberculosis), Mycobacterium leprae (causing leprosy), and non-tuberculous mycobacterial pathogens including Mycobacterium ulcerans. Macrophages are mycobacterial targets and they play an essential role in the host immune response to mycobacteria. This review aims to provide a comprehensive understanding of the immune-metabolic adaptations of the macrophage to mycobacterial infections. This metabolic rewiring involves changes in glycolysis and oxidative metabolism, as well as in the use of fatty acids and that of metals such as iron, zinc and copper. The macrophage metabolic adaptations result in changes in intracellular metabolites, which can post-translationally modify proteins including histones, with potential for shaping the epigenetic landscape. This review will also cover how critical tuberculosis co-morbidities such as smoking, diabetes and HIV infection shape host metabolic responses and impact disease outcome. Finally, we will explore how the immune-metabolic knowledge gained in the last decades can be harnessed towards the design of novel diagnostic and therapeutic tools, as well as vaccines.

Use of untargeted magnetic beads to capture Mycobacterium smegmatis and Mycobacterium avium paratuberculosis prior detection by mycobacteriophage D29 and Real-Time-PCR

Dynabeads® M-280 Tosylactivated (untargeted magnetic beads) were evaluated to capture Mycobacterium smegmatis and Mycobacterium avium subspecies paratuberculosis (MAP) from spiked feces, milk, and urine. Untargeted magnetic beads added to the spiked samples were slightly mixed for 1 hour and separated in a magnetic rack for further detection. Beads recovered more M. smegmatis cells from PBS suspension that the centrifugation method; these results were confirmed by the recovery of 96.31% of 1.68 x 104 CFU/mL viable M. smegmatis by beads and 0% by centrifugation. Likewise, the F57-qPCR detection of MAP cells, after being recovered by beads and centrifugation, were different; cycle threshold (Ct) was lower (p<0.05) for the detection of MAP cells recovered by beads than centrifugation. Magnetic separation of MAP cells from milk, urine, and feces specimens were detected by amplifying F57 and IS900 sequences. Ct values demonstrated that beads captured no less than 109 CFU/mL from feces and no less than 104 CFU/mL of MAP cells from milk and urine suspensions. Milk proteins were denatured by Proteinase k before capturing MAP cells by magnetic beads. M. smegmatis coupled to magnetic beads were infected by mycobacteriophage D29; plaque former units were observed clearly from urine containing 2 x 105 and 2 x 103 CFU/mL M. smegmatis in 24 hours. The results of this study encourage further effort to rule out the use of untargeted beads as a simple tool for diagnosis of Johne′s disease and other mycobacterial diseases such as tuberculosis.

Latticed Gold Nanoparticle Conjugation via Monomeric Streptavidin in Lateral Flow Assay for Detection of Autoantibody to Interferon-Gamma

Adult-onset immunodeficiency syndrome (AOID) patients with autoantibodies (autoAbs) against interferon-gamma (IFN-γ) generally suffer from recurrent and recalcitrant disseminated non-tuberculous mycobacterial diseases. Since the early stages of AOID do not present specific symptoms, diagnosis and treatment of the condition are not practical. A simplified diagnostic method for differentiating AOID from other immunodeficiencies, such as HIV infection, was created. Anti-IFN-γ is generally identified using enzyme-linked immunosorbent assay (ELISA), which involves an instrument and a cumbersome process. Recombinant IFN-γ indirectly conjugated to colloidal gold was used in the modified immunochromatographic (IC) strips. The biotinylated-IFN-γ was incorporated with colloidal-gold-labeled 6HIS-maltose binding protein-monomeric streptavidin (6HISMBP-mSA) and absorbed at the conjugate pad. The efficacy of the IC strip upon applying an anti-IFN-γ autoAb cut-off ELISA titer of 2500, the sensitivity and specificity were 84% and 90.24%, respectively. When a cut-off ELISA titer of 500 was applied, the sensitivity and specificity were 73.52% and 100%, respectively.

Recent developments in the diagnosis and treatment of extrapulmonary non-tuberculous mycobacterial diseases

Diseases due to pathogenic mycobacteria cause significant health and economic impact on humans worldwide. Although mycobacterial diseases primarily affect the lungs, the involvement of extrapulmonary organs has also gained ground, particularly among individuals with co‐existing medical conditions. Besides Mycobacterium tuberculosis complex organisms, non‐tuberculous mycobacteria (NTM) are also known to cause pulmonary and extrapulmonary diseases. Primary and disseminated extrapulmonary mycobacterial infections affect the brain, eye, mouth, tongue, lymph nodes of the neck, spine, bones, muscles, skin, pleura, pericardium, gastro‐intestinal, peritoneum and genito‐urinary system. The clinical presentation of extrapulmonary mycobacterial diseases, including systemic symptoms, of M. tuberculosis‐infected cases and NTM‐infected cases is similar. Moreover, extrapulmonary mycobacterial diseases are complicated by the involvement of diverse bacterial species as aetiological agents. Culture and molecular techniques are used to differentiate NTM from Mycobacterium tuberculosis and to classify sub‐species of the pathogens. As sub‐speciation and drug susceptibility profiling are critical factors in treating extrapulmonary NTM diseases, there are often significant delays in initiating treatment and customising the therapeutic regimen. Here, we summarise the clinical symptoms of NTM diseases in various extrapulmonary organs, and discuss the recent trends in diagnosing and treating these diseases. We also highlight the complications associated with the management of extrapulmonary NTM disease.

Association between Serum Anti-glycopeptidolipid-core IgA Antibody Titers and Clinical Characteristics of Mycobacterium Avium Complex Pulmonary Disease

Mycobacterium avium complex pulmonary disease (MAC-PD) can be serologically diagnosed according to the presence of anti-glycopeptidolipid (GPL)-core IgA antibodies. However, few studies have examined the association between serum anti-GPL-core IgA antibody titers and the clinical characteristics of patients with MAC-PD. From April 2014 to June 2019, we determined the level of anti-GPL-core IgA antibodies in 489 MAC-PD patients at our institute. Of them, 89 patients fulfilled the criteria of the American Thoracic Society and the Infectious Diseases Society of America statement on the diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases. These patients were divided into antibody-positive (n = 59) or -negative (n = 30) groups according to their serum anti-GPL-core IgA antibody results. Additionally, the positive antibody group was further divided into a strong positive group (n = 27) and a weak positive group (n = 32), and their clinical characteristics were retrospectively compared. Disease progression requiring treatment during the 12 months following diagnosis and extensive radiological findings were significantly abundant in the strong positive group compared with the weak positive group. Our findings revealed that serum anti-GPL-core IgA antibody titers are useful not only for diagnosing MAC-PD but also for predicting the risk of exacerbation.

Clinical and Molecular Findings in Mendelian Susceptibility to Mycobacterial Diseases: Experience From India

Mendelian Susceptibility to Mycobacterial diseases (MSMD) are a group of innate immune defects with more than 17 genes and 32 clinical phenotypes identified. Defects in the IFN-γ mediated immunity lead to an increased susceptibility to intracellular pathogens like mycobacteria including attenuated Mycobacterium bovis-Bacillus Calmette-Guérin (BCG) vaccine strains and non-tuberculous environmental mycobacteria (NTM), Salmonella, fungi, parasites like Leishmania and some viruses, in otherwise healthy individuals. Mutations in the IL12RB1 gene are the commonest genetic defects identified. This retrospective study reports the clinical, immunological, and molecular characteristics of a cohort of 55 MSMD patients from 10 centers across India. Mycobacterial infection was confirmed by GeneXpert, Histopathology, and acid fast bacilli staining. Immunological workup included lymphocyte subset analysis, Nitro blue tetrazolium (NBT) test, immunoglobulin levels, and flow-cytometric evaluation of the IFN-γ mediated immunity. Genetic analysis was done by next generation sequencing (NGS). Disseminated BCG-osis was the commonest presenting manifestation (82%) with a median age of presentation of 6 months due to the practice of BCG vaccination at birth. This was followed by infection with Salmonella and non-typhi Salmonella (13%), Cytomegalovirus (CMV) (11%), Candida (7%), NTM (4%), and Histoplasma (2%). Thirty-six percent of patients in cohort were infected by more than one organism. This study is the largest cohort of MSMD patients reported from India to the best of our knowledge and we highlight the importance of work up for IL-12/IL-23/ISG15/IFN-γ circuit in all patients with BCG-osis and suspected MSMD irrespective of age.

Performance of Interferon-Gamma Release Assays in the Diagnosis of Nontuberculous Mycobacterial Diseases—A Retrospective Survey From 2011 to 2019

There is an urgent need for precise diagnosis to distinguish nontuberculous mycobacterial (NTM) diseases from pulmonary tuberculosis (PTB) and other respiratory diseases. The aim of this study is to evaluate the diagnostic performance of Interferon-gamma (IFN-γ) release assays (IGRAs), including antigen-specific peripheral blood-based quantitative T cell assay (T-SPOT.TB) and QuantiFERON-TB-Gold-Test (QFT-G), in differentiating NTM infections (N = 1,407) from culture-confirmed PTB (N = 1,828) and other respiratory diseases (N = 2,652). At specie level, 2.56%, 10.73%, and 16.49% of NTM-infected patients were infected by Mycobacterium kansasii, M. abscessus, and with M. avmm-intracellulare complex (MAC), respectively. Valid analyses of T-SPOT.TB (ESAT-6, CFP-10) and QFT-G were available for 37.03% and 85.79% in NTM-infected patients, including zero and 100% (36/36) of M. kansasii infection, 21.85% (33/151) and 92.05% (139/151) of M. abscessus infection, and 17.67% (41/232) and 91.24% (211/232) of MAC infection. Based on means comparisons and further ROC analysis, T-SPOT.TB and QFT-G performed moderate accuracy when discriminating NTM from PTB at modified cut-off values (ESAT-6 &lt; 4 SFCs, CFP-10 &lt; 3 SFCs, and QFT-G &lt; 0.667 IU/ml), with corresponding AUC values of 0.7560, 0.7699, and 0.856. At species level of NTM, QFT-G effectively distinguished between MAC (AUC=0.8778), M. kansasii (AUC=0.8834) or M. abscessus (AUC=0.8783) than T-SPOT.TB. No significant differences in discriminatory power of these three IGRA tools were observed when differentiating NTM and Controls. Our results demonstrated that T-SPOT.TB and QFT-G were both efficient methods for differentiating NTM disease from PTB, and QFT-G possessed sufficient discriminatory power to distinguish infections by different NTM species.