Yield & accuracy of Gastric Lavage in non-expectorating adults with Suspected Pulmonary Tuberculosis

Objective

To determine the yield of Gastric lavage (GL) in non-expectorating adults with suspected Pulmonary Tuberculosis (PTB) and accuracy of GL-AFB smear with GL-GeneXpert (GXP) by taking AFB culture as gold standard.

Methods

Cross-sectional study on suspected PTB patients was done at Ojha Institute of Chest Diseases during period 16th July 2020 till 15th January 2021. Adult patients of either gender suspected to have PTB and not expectorating were included. GL was performed and sent for AFB smear, GXP and AFB culture. Odds ratio, sensitivity and specificity were calculated.

Results

After informed written consent, 206 patients, mean age was 38.17 ±17.30 years were inducted, including 89 (43.2%) males and 117 (56.8%) females. Gene Xpert, AFB smear & AFB culture were positive in 83(40%), 50 (24%) & 72 (35%) respectively in GL samples. Odds of PTB were 3.95 times higher among patients with ≤1 month of duration of symptoms (aOR 3.95, 95% CI 1.82-8.57, p-value 0.001), 6.24 times higher among patients with weight loss (aOR 6.24, 95% CI 3.03-12.84, p-value <0.001), and 4.22 times higher among patients with cavitation (aOR 4.22, 95% CI 1.99-8.93, p-value <0.001). GL-AFB smear showed sensitivity 63.89%, specificity 97.01%, positive predicted value 92%, negative predicted value 83.3%, and overall diagnostic accuracy 85.4%. Whereas GL-GXP showed sensitivity 94.4%, specificity 88.81%, positive predicted value 81.93%, negative predicted value 96.75%, and overall diagnostic accuracy 90.78%.

Conclusion

Yield of GL significant to detect PTB in suspected cases who are not expectorating. GL-GXP diagnostic accuracy and sensitivity is higher than GL-AFB smear.

Design, synthesis and anti-Tb evaluation of chalcone derivatives as novel inhibitors of InhA

A series of halogenated chalcone derivatives were designed and developed for anti-tubercular activity. Novel molecules were designed and in-silico screening were performed using admetSAR, SwissADME, and Osiris Property Explorer. From the initial filter the top 10 compounds were docked using the Autodock tool 1.5.6. and the binding energies of the docked compounds were higher than the standard drugs Isoniazid.and Ethionamide. Based on the in-silico and docking results, the top halogenated chalcones were synthesized and characterized using FT-IR, mass spectrometry, 1H, and 13C NMR spectroscopy. The chalcones were further evaluated for anti-tubercular activity using MABA against the H37Rv strain. Among the series of compounds, DK12 and DK14 showed potent in-vitro activity, with MICs of 0.8 µg/ml, in comparison with 1.6 µg/ml of the first-line drug Isoniazid. Further molecular dynamics simulations studies for 100 ns revealed that the key interaction with TYR 158 were observed in both DK12 and DK14 in the InhA active site. The compound DK12 further showed significant interactions with PHE 149 and ARG 153 residues and is a hit molecule among the series. Further DK12 and DK14 does not show any significance toxicity. The compounds DK12 needs to be optimized and further investigation to be carried out against InhA.Communicated by Ramaswamy H. Sarma.

TBC and COVID: an interplay between two infections

INTRODUCTION

In an historical era dominated by the Sars-Cov-2 pandemic, a fact of growing interest emerges regarding co-infection with Mycobacterium Tuberculosis (M.Tuberculosis). This represents today an important clinical and diagnostic challenge, as the two pathogens are capable, through specific immunopathological mechanisms, of interacting with each other, determining a severe respiratory condition with a severe prognosis.

AREAS COVERED

With this review we wanted to collect and analyze the latest scientific evidence concerning the main immunopathogenetic mechanisms shared by these two respiratory pathogens, with particular interest in the possible iatrogenic factors favoring coinfection and the need to define a multidisciplinary and standardized screening tools aimed to identify coinfection early, ensuring the best clinical and therapeutic management.

EXPERT OPINION

The existence of a direct immunopathogenetic link between COVID-19 and TB indirectly contributes to mutual morbidity and mortality. The identification and application of early and standardized screening tools aimed at the identification of this condition is essential, in addition to vaccine prevention.

Middlebrook 7h11 reduces invalid results and turnaround time of phenotypic drug-susceptibility testing of M. tuberculosis

Background

Phenotypic drug-susceptibility testing (pDST), which relies on growth inhibition in the drug-containing media, remains a challenge for fastidious Mycobacterium tuberculosis complex (MTBc) isolates due to insufficient growth on the growth controls (GC). Middlebrook 7H11 (M7H11) medium contains casein hydrolysate, which may favor the growth of such strains.

Method

In this study, we tested whether M7H11 reduces invalid results due to insufficient growth on the GCs and the turnaround time (TAT) of pDST for MTBc compared to Middlebrook 7H10 (M7H10) without affecting the accuracy of the pDST results and how it differs between rifampicin- and isoniazid-susceptible non multi-drug resistant (non-MDR), MDR and MDR with additional resistance to fluoroquinolones (Pre-XDR) MTBc isolates. We compared the proportions of invalid pDST results due to lack of growth on the GCs, TATs of valid parallel drug-susceptibility testings as an indicator of speed of MTBc growth, and colony-forming unit (CFU) count on the most diluted GC of the parallel pDSTs after equal incubation periods as an indicator of growth abundance on M7H11 and M7H10. We also analyzed the agreement between the pDST results of the same drug or drugs in the same drug class, tested in parallel on both media.

Results

For MDR and pre-XDR isolates, relative to M7H10, M7H11 significantly reduced the occurrence of invalid pDST results due to insufficient growth on the GCs (odds ratio [OR] = ∞ [95% confidence interval (CI) 1.9-∞], P = 0.004 for MDR, OR = ∞ [95% CI 3.3-∞], P = 0.0001 for pre-XDR) and the TAT of pDSTs (OR = 17 [95% CI 2.6-710.4], P = 0.0001 for MDR, OR = 9.3 [95% CI 4.0-26.5], P < 0.0001 for pre-XDR). The growth abundance of MTBc on M7H11 was significantly higher compared to M7H10 (17 CFU on M7H10 vs. 28 on M7H11), irrespective of drug-resistance profiles. The agreement between the pDST results between the two media was high (Cohen's k > 0.98).

Conclusion

Our study findings suggest that M7H11 is preferred over M7H10 for pDSTs of MTBc isolates.

Relation between Serological Findings and Expression of IL-1β and IL-6 genes in Patients Infected with Mycobacterium Tuberculosis in Iraq

Mycobacterium Tuberculosis (TB) is one of the serious bacterial infections that cause diseases and may lead to death. In this study, 178 individuals were examined for TB infection at Baghdad TB center during the period from 15^th January to 1^st October 2021. Out of 178 participants, 73 were shown to be positive for TB infection, while 105 showed negative results. According to the results, there was no significant variation between infected males and females with TB in comparison to the control group (P>0.05). The results showed that the mean age of the patients for both males and females was in the range of 2-65 years. Additionally, there were significant differences in patients with TB compared to the control group in terms of the weight loss of 8.82 ± 6.75 Kg, red blood cell (RBC) count (3.43 ± 0.56) × 10⁶/μl, white blood cell (WBC) count (3.12 ± 1.57) × 10⁶/μl, platelet count (1.03 ± 0.56) × 10⁶/μl, and hemoglobin level (6.66 ± 1.34) g/dl. A total of 30 TB patients and 50 normal individuals were genotyped to detect the IL-1β rs 114534 gene. The polymerase chain reaction (PCR) was used for exon amplification in region 5 of the ILB1 gene in the TB patients by using specific primers. The finding showed that there was an amplified product of 249bp located in chromosome 2q13-14. A total of 30 TB patients and 50 normal individuals were also genotyped to detect the IL-6 rs 1800795 gene. The PCR was used for amplification of the IL-6 gene in TB patients by using specific primers. The finding showed that there was an amplified product of 431 bp located in chromosome 7p15-p2. The expression of the ILB1 gene was investigated in TB patients and healthy controls by using qPT-PCR. Results showed that there was a high Ct value for patients and controls with a high Ct value of templates, preoperational to the total ribonucleic acid (RNA) concentration and gene expression. The expression of the IL-6 gene was investigated in TB patients and healthy controls by using qPT-PCR. Our findings revealed a high Ct value for patients and controls with a high Ct value of templates, preoperational to the total RNA concentration and gene expression.

Mycobacterium tuberculosis ESAT6 modulates host innate immunity by downregulating miR-222-3p target PTEN

Tuberculosis (TB) remains a major cause of mortality and morbidity worldwide, and it is instant to discover novel anti-TB drugs due to the rapidly growing drug-resistance TB. Mycobacterium tuberculosis (Mtb) secreted effector ESAT6 plays a critical role in modulation miRNAs to regulate host defense mechanisms during Mtb infection, it can be a possible target for new tuberculosis drugs. The non-tuberculous mycobacteria Mycobacterium smegmatis (M. smegmatis) and Mtb have high gene homology but no pathogenicity. We used ESAT6 to interfere with macrophages or mice infected by M. smegmatis and determined that it enhanced the survival rate of bacteria and regulated miR-222-3p target PTEN. Expression of miR-222-3p reduced and PTEN enhanced with the progression of macrophages infected by M. smegmatis with ESAT6 co-incubation. MiR-222-3p overexpression diminished M. smegmatis survival and upregulated proinflammatory cytokines. VO-Ohpic trihydrate (PTEN inhibitor) reduced M. smegmatis survival and upregulated proinflammatory cytokines in vivo and in vitro, and VO-Ohpic trihydrate reversed the tissue damage of mouse organs caused by ESAT6. These results uncover an ESAT6 dependent role for miR-222-3p and its target PTEN in regulating host immune responses to bacterial infection and may provide a potential site for the development of anti-tuberculosis drugs that specifically antagonize the virulence of ESAT6.

Mycobacterium Tuberculosis Peritonitis in Peritoneal Dialysis Patients: A Scoping Review

BACKGROUND

The clinical syndrome of Mycobacterium tuberculosis (TB) peritoneal dialysis (PD) peritonitis is poorly understood. Whether local TB patterns modify the clinical syndrome, and what factors associate with poor outcomes is also unknown.

METHODS

A scoping review identified published cases of TB PD peritonitis. Cases from low and high TB burden areas were compared, and cases that did or did not suffer a poor clinical outcome were compared.

RESULTS

There were 216 cases identified. Demographics, presentation, diagnosis, treatment and outcomes were described. Significant delays in diagnosis were common (6.1 weeks) and were longer in patients from low TB burden regions (7.3 vs 3.7 weeks). In low TB burden areas, slower diagnostic methods were more commonly used like PD fluid culture (64.3 vs. 32.7%), and treatment was less likely with quinolone antibiotics (6.9 vs 34.1%). Higher national TB incidence and lower GDP per capita were found in cases that suffered PD catheter removal or death. Diagnostic delays were not longer in cases in which a patient suffered PD catheter removal or death. Cases that suffered death were older (51.9 vs 45.1 years) and less likely female (37.8 vs. 55.7%). Removal of PD catheter was more common in cases in which a patient died (62.0 vs 49.1%).

CONCLUSIONS

Outcomes in TB PD peritonitis are best predicted by national TB incidence, patient age and sex. Several unique features are identified to alert clinicians to use more rapid diagnostic methods that might enhance outcomes in TB PD peritonitis. This article is protected by copyright. All rights reserved.

Cytochrome bc1-aa3 oxidase supercomplex as emerging and potential drug target against tuberculosis

The cytochrome bc1-aa3 supercomplex plays an essential role in the cellular respiratory system of Mycobacterium Tuberculosis. It transfers electrons from menaquinol to cytochrome aa3 (Complex IV) via cytochrome bc1 (Complex III), which reduces the oxygen. The electron transfer from a variety of donors into oxygen through the respiratory electron transport chain is essential to pump protons across the membrane creating an electrochemical transmembrane gradient (proton motive force, PMF) that regulates the synthesis of ATP via the oxidative phosphorylation process. Cytochrome bc1-aa3 supercomplex in M. tuberculosis is, therefore, a major drug target for antibiotic action. In recent years, several respiratory chain components have been targeted for developing new candidate drugs, illustrating the therapeutic potential of obstructing energy conversion of M. tuberculosis. The recently available cryo-EM structure of mycobacterial cytochrome bc1-aa3 supercomplex with open and closed conformations has opened new avenues for understanding its structure and function for developing more effective, new therapeutics against pulmonary tuberculosis. In this review, we discuss the role and function of several components, subunits, and drug targeting elements of the supercomplex cytochrome bc1-aa3, and its potential inhibitors in detail.

Mutational Frequencies in Mycobacterial rpoB gene using GeneXpert/MTB Rif Assay in Rifampicin Resistant patients at a tertiary care setting in Urban Sindh, Pakistan: Analysis from a Five-Year Period

Objectives

To assess the mutational frequencies in Mycobacterial rpoB gene using GeneXpert/MTB Rif Assay in rifampicin resistant patients during 2013-2017 at a tertiary care setting in Urban Sindh, Pakistan.

Methods

This Retrospective Descriptive Cross-Sectional Study was conducted at the TB laboratories, Ojha Institute of Chest Diseases, Dow University of Health Sciences. The record of 713 positive cases of Rifampicin Resistant Tuberculosis from January 2013 to December 2017 were analysed. These were diagnosed using GeneXpert® that detects mutations in the 81 base pair region of rpoB gene with the help of five molecular probes A, B, C, D and E. All invalid and extra pulmonary samples were excluded.

Results

In total, 713 cases were found to be rifampicin resistant during the five-year period, among which 374 (52.45%) were males while 339 (47.55%) were females. Among the five standard probes A, B, C, D and E, 97.48% of the cases had a single mutation. Among these, mutations in Probe E (66.48%) were the most common, followed by Probe B (14.3%) and Probe D (11.08%). Only 13 cases (1.82%) of double mutations and five cases (0.7%) of triple mutations were detected.

Conclusion

The rpoB gene Probe E region 529-533 appears the most potent site for a mutation and development of rifampicin resistance in the rpoB gene in Mycobacterium tuberculosis, that encodes the β-subunit of RNA polymerase. The most affected age-group in both males and females is 19-45 Years.

Vitamin D Deficiency among Patients with Tuberculosis: a Cross-Sectional Study in Iranian-Azari Population

BACKGROUND

Vitamin D deficiency or insufficiency has been conducted with increased risk for tuberculosis (TB). Despite this association, discrepancies exist among different studies in different regions. The aim of this study was to evaluate the prevalence of vitamin D deficiency and its predictors in tuberculosis among the Iranian-Azari population.

MATERIALS AND METHODS

A total of 60 participants were enrolled in this study, 30 of which were newly diagnosed TB patients and 30 were healthy volunteers. At least two serum samples were collected, the first sample before the start of anti-TB treatment and the second sample 3 months after the effective treatment.

RESULTS

The prevalence of vitamin D deficiency (25 patients vs. 2 healthy individuals; P<0.001) and serum levels of the vitamin D (22.66±15.17 vs. 73.03±25.6 ng/mL; P<0.001) were significantly higher in patients with TB than healthy subjects. Likewise, the prevalence of vitamin D deficiency in the extrapulmonary TB group was higher than that of the pulmonary TB, but this difference was not statistically significant (P=0 .397). Moreover, there was no significant difference between mean levels of vitamin D in patients with tuberculosis before and after treatment (P = 0.787). Linear regression analysis showed there was no significant relationship between vitamin D levels after treatment and age, gender, body site of tuberculosis, and vitamin D levels before treatment, P≥0.68.

CONCLUSION

Vitamin D deficiency is higher in patients with tuberculosis than healthy individuals.

Diagnosis of local hepatic tuberculosis through next-generation sequencing: Smarter, faster and better

BACKGROUND

A 45-year-old man who complained of continuous fever and multiple hepatic masses was admitted to our hospital. Repeated MRI manifestations were similar while each radiological report suggested contradictory diagnosis pointing to infections or malignances respectively. Pathologic examination of the liver tissue showed no direct evidence of either infections or tumor. We performed next-generation sequencing on the liver tissue and peripheral blood to further investigate the possible etiology.

METHODS

High throughput sequencing was performed on the liver lesion tissues using BGISEQ-100 platform, and data was mapped to the Microbial Genome Databases after filtering low quality data and human reads.

RESULTS

We identified a total of 299 sequencing reads of Mycobacterium tuberculosis (M. tuberculosis) complex sequences from the liver tissue, including 8, 229 of 4,424,435 of the M. tuberculosis nucleotide sequences, and Mycobacterium africanum, Mycobacterium bovis, and Mycobacterium canettii were also detected due to the 99.9% identical rate among these strains. No specific Mycobacterial tuberculosis nucleotide sequence was detected in the sample of peripheral blood. Patient's symptom quickly recovered after anti-tuberculosis treatment and repeated Ziehl-Neelsen staining of the liver tissue finally identified small numbers of positive bacillus.

CONCLUSIONS

The diagnosis of this patient was difficult to establish before the next-generation sequencing because of contradictive radiological results and negative pathological findings. More sensitive diagnostic methods are urgently needed. This is the first case reporting hepatic tuberculosis confirmed by the next-generation sequencing, and marks the promising potential of the application of the next-generation sequencing in the diagnosis of hepatic lesions with unknown etiology.

Identification of Novel Physiological Substrates of Mycobacterium bovis BCG Protein Kinase G (PknG) by Label-free Quantitative Phosphoproteomics

Mycobacterial Ser/Thr kinases play a critical role in bacterial physiology and pathogenesis. Linking kinases to the substrates they phosphorylate in vivo, thereby elucidating their exact functions, is still a challenge. The aim of this work was to associate protein phosphorylation in mycobacteria with important subsequent macro cellular events by identifying the physiological substrates of PknG in Mycobacterium bovis BCG. The study compared the phosphoproteome dynamics during the batch growth of M. bovis BCG versus the respective PknG knock-out mutant (ΔPknG-BCG) strains. We employed TiO₂ phosphopeptide enrichment techniques combined with label-free quantitative phosphoproteomics workflow on LC-MS/MS. The comprehensive analysis of label-free data identified 603 phosphopeptides on 307 phosphoproteins with high confidence. Fifty-five phosphopeptides were differentially phosphorylated, of these, 23 phosphopeptides were phosphorylated in M. bovis BCG wild-type only and not in the mutant. These were further validated through targeted mass spectrometry assays (PRMs). Kinase-peptide docking studies based on a published crystal structure of PknG in complex with GarA revealed that the majority of identified phosphosites presented docking scores close to that seen in previously described PknG substrates, GarA, and ribosomal protein L13. Six out of the 22 phosphoproteins had higher docking scores than GarA, consistent with the proteins identified here being true PknG substrates. Based on protein functional analysis of the PknG substrates identified, this study confirms that PknG plays an important regulatory role in mycobacterial metabolism, through phosphorylation of ATP binding proteins and enzymes in the TCA cycle. This work also reinforces PknG's regulation of protein translation and folding machinery.

[MGIT and other methods for diagnosing tuberculosis in a private hospital system with low incidence]

BACKGROUND

Tuberculosis (TB) is still a threat to public health; in 2014 caused 1.5 million deaths worldwide; in hospitals where the prevalence of TB is low, it is appropriate to evaluate the effectiveness of tests to diagnose it.

METHODS

We reviewed reports of airway clinical specimens sent for studies of tuberculosis to the microbiology laboratory from Tec Salud System private hospitals (400 beds) in the metropolitan area of ​​Monterrey, NL, from May 2012 to December 2015. In conjunction with Ziehl-Neelsen (ZN) stain, and solid Lowenstein-Jensen medium (LJ), our laboratory resources also include fluorescent LED microscopy (Carl Zeiss Microscopy Products), MGIT 320 (Mycobacteria Growth Indicator Tube liquid culture detection system, Becton Dickinson), and recently incorporated a real-time PCR system the Xpert MTB/RIF test (Cepheid, Sunnyvale, CA).

RESULTS

In 731 respiratory specimens from 510 patients, M. tuberculosis was isolated from 78 samples belonging to 50 patients on LJ and MGIT LJ 42 (84%) and MGIT 49, (98%) of the samples. From 41 patients identified, 26 (63.4%) were positive to fluorescein, and 25 (60.9%) with Ziehl-Neelsen stain. Real time PCR (Xpert TB) was positive in 13 out of 17 patient-airway samples (76.4%).

CONCLUSIONS

Usefulness of liquid culture (MGIT) and solid culture (LJ) is shown; the first can significantly cut incubation times.

Nanomaterials in the Prevention, Diagnosis, and Treatment of Mycobacterium Tuberculosis Infections

Despite the tremendous advancements that have been made in biomedical research, Mycobacterium tuberculosis (TB) still remains one of the top 10 causes of death worldwide, outpacing the Human Immunodeficiency Virus as a leading cause of death from an infectious disease. In the light of such significant disease burden, tremendous efforts have been made worldwide to stem this burgeoning spread of disease. The use of nanomaterials in TB management has increased in the past decade, particularly in the areas of early TB detection, prevention, and treatment. Nanomaterials have been proven to be efficacious in the rapid and accurate detection of TB pathogens. Novel nanocarriers have also shown tremendous promise in improving drug delivery, potentially enhancing drug concentrations in target organs while at the same time, reducing treatment frequency. In addition, the engineering of antigen nanocarriers represents an exciting front in TB research, potentially paving the way for the successful development of a new class of effective TB vaccines. This article discusses epidemiology and pathogenesis of TB infections, current TB therapeutics, advanced nanomaterials for anti-TB drug delivery, and TB vaccines. In addition, challenges and future perspectives in developing safe and effective nanomaterials in TB diagnosis and therapy are also presented.

Macrophage Immune Response Suppression by Recombinant Mycobacterium tuberculosis Antigens, the ESAT-6, CFP-10, and ESAT-6/CFP-10 Fusion Proteins

BACKGROUND

Macrophage immune responses are affected by the secretory proteins of Mycobacterium tuberculosis (Mtb). This study aimed to examine the immune responses of macrophages to Mtb secretory antigens, namely ESAT-6, CFP-10, and ESAT-6/CFP-10.

METHODS

THP-1 cells (a human monocytic cell line) were cultured and differentiated to macrophages by phorbol 12-myristate 13-acetate. The cytotoxicity of the recombinant Mtb proteins was assessed using the MTT assay. Two important immune responses of macrophages, namely NO and ROS production, were measured in response to the ESAT-6, CFP-10, and ESAT-6/CFP-10 antigens. The data were analyzed using one-way ANOVA with SPSS, version 16, and considered significant at P<0.05.

RESULTS

The results showed that the ESAT-6, CFP-10, and ESAT-6/CFP-10 proteins markedly reduced macrophage immune response. The treatment of the THP-1-differentiated cells with ESAT-6, CFP-10, and ESAT-6/CFP-10 reduced NO and ROS production. The treated THP-1-differentiated cells exhibited less inducible NO synthase activity than did the untreated cells. No toxic effect on macrophage viability was observed for the applied proteins at the different concentrations.

CONCLUSION

It seems that the decline in macrophage immune response is due to the suppression of NO and ROS production pathways without any effect on cell viability.

Patterns of Drug Resistance Among Tuberculosis Patients in West and Northwestern Iran

Background:

Tuberculosis (TB) is the leading cause of morbidity and mortality among chronic infectious diseases.

Objective:

The goal of this cross-sectional study (2011-2013;2013) was to examine the patterns of TB drug resistance among HIV-negative pulmonary TB patients in regions near the Iranian border.

Method:

To this end, MTB isolates were harvested from 300 HIV-negative, pulmonary smear-positive TB patients from the northwest and west Iranian border provinces. Isolates were subjected to first and second-line drug susceptibility testing by the 1% proportion method. Demographic and clinical data were provided using a questionnaire and information from patient records. Results were analyzed using SPSS-18.

Results:

The mean age of the patients was 52.03 years and 54.3% were male. The prevalence of resistance to any TB drug was 13.6% (38 cases). Eleven percent of the new treatment TB group (28 patients) and 40.7% of the retreatment TB group (11 patients) were resistant to all TB drugs. Twelve (4.3%) patients had multidrug-resistant tuberculosis (MDR-TB) (2.38% in the new TB treatment group and 23.1% in the retreatment group). One patient had extensively drug-resistant tuberculosis (XDR-TB). There was a statistically significant relationship between TB drug resistance and smoking (p=0.02) and a history of migration from village to city (p=0.04), also between TB drug resistance and recurrence of TB in patients that had previously received treatment (p<0.001).

Conclusion:

Knowledge of drug resistance patterns for new and previously treated cases is critical for effective control of MDR-TB in different regions of the country. The burden of MDR-TB in retreatment cases was high. Previous TB treatment was one of the most important mokers and those who had a history of rural to urban migration were at high risk for the occurrence of TB drug resistance.

Tuberculosis of the Cheek: A Rare Presentation

Tuberculosis (TB) typically attacks the lungs. The oral lesions either primary or secondary are rarely seen and often overlooked by the clinician. More so, their atypical presentations make the diagnosis challenging; especially when they are present before the systemic symptoms become apparent. We report a case of primary tuberculosis in a 4 year old female child in a very uncommon location, the cheek. The timely diagnosis and antitubercular therapy resulted in complete resolution of the swelling within 6 months.

Young Adult Hip: Reactivation of dormant, previously undiagnosed Mycobacterium Tuberculosis infection following intra-articular steroid injection

INTRODUCTION

Tuberculosis (TB) still remains a common problem in the UK and, with the increasing number of patients being offered arthroplasties; periprosthetic involvement is not uncommon anymore. However, the diagnosis of TB infected arthroplasties still remains difficult and misdiagnosis is common, therefore delaying treatment.

CASE REPORT

We describe a 36-years old Caucasian female with no known history of TB who presented with hip pain thought to be due to femoro-acetabular impingement (FAI). In the course of 18 months, the patient had been investigated extensively; including steroid injection, hip arthroscopy (including synovial biopsies), and eventually a total hip arthroplasty. During arthroplasty, further extensive biopsies were performed which raised the suspicion of TB on histology. Further synovial biopsies obtained arthroscopically were microbiologically positive for TB (PCR). The patient was sent to an infectious disease specialist. It appeared that the patient had TB in the past, of which she was unaware.

CONCLUSION

We hypothesise that the immunosuppressant effects of the steroid injections she received reactivated her TB.

Young Adult Hip: Reactivation of dormant, previously undiagnosed Mycobacterium Tuberculosis infection following intra-articular steroid injection

INTRODUCTION

Tuberculosis (TB) still remains a common problem in the UK and, with the increasing number of patients being offered arthroplasties; periprosthetic involvement is not uncommon anymore. However, the diagnosis of TB infected arthroplasties still remains difficult and misdiagnosis is common, therefore delaying treatment.

CASE REPORT

We describe a 36-years old Caucasian female with no known history of TB who presented with hip pain thought to be due to femoro-acetabular impingement (FAI). In the course of 18 months, the patient had been investigated extensively; including steroid injection, hip arthroscopy (including synovial biopsies), and eventually a total hip arthroplasty. During arthroplasty, further extensive biopsies were performed which raised the suspicion of TB on histology. Further synovial biopsies obtained arthroscopically were microbiologically positive for TB (PCR). The patient was sent to an infectious disease specialist. It appeared that the patient had TB in the past, of which she was unaware.

CONCLUSION

We hypothesise that the immunosuppressant effects of the steroid injections she received reactivated her TB.

Molecular Epidemiology of Mycobacterium Tuberculosis Strains in the North-West and West of Iran

Background:

Identifying Mycobacterium tuberculosis (MTB) transmission type is a key step in the control of this disease.

Aim:

This study aimed to determine the path and transmission type of MTB and the insertion sequence IS6110 band number and verify their relationship to demographic and clinical risk factors.

Subjects and Methods:

In this cross-sectional study, 64 MTB patients from three border provinces of Iran were selected after full clinical history and physical evaluation design. The drug susceptibility testing was carried out using the standard proportion technique on sputum samples. Isolates tested with restriction fragment length polymorphism technique used IS6110.

Results:

Recent transmission of disease was 33/50 (66%) based on clustering rate. The IS6110 band number had a significant relationship with drug resistance detected in proportion method tested by univariate linear regression (P < 0.01). Furthermore, the IS6110 band number had association with Bacillus Calmette–Guérin vaccination history (P = 0.02), sex (P < 0.01), and purified protein derivative (PPD) reaction size (P < 0.01) tested by multiple analysis. The risk of recent transmission inferred from the clustering rate was significantly higher in patients from Western provinces compared to those from the North-West province (P = 0.048). However, age (P = 0.39), gender (P = 0.16), vaccination history (P = 0.57), drug susceptibility, and PPD (P < 0.6) were independent of clustering. The largest cluster of up to six subjects was found in the Western provinces.

Conclusion:

Recent MTB transmission was much more common in the West compared to the North-West of Iran. Large MTB clusters with strong epidemiological links may be reflective of a disease outbreak. Correlation noted between the IS6110 band number and vaccination history; PPD size and female gender necessitates further studies.

Expression and Purification of the Recombinant Cytochrome P450 CYP141 Protein of Mycobacterium Tuberculosis as a Diagnostic Tool and Vaccine Production

Background:

Tuberculosis (TB) is regarded as a health problem worldwide, particularly in developing countries. Mycobacterium tuberculosis (M. tuberculosis) is the cause of this disease. Approximately two billion people worldwide are infected by M. tuberculosis and annually about two million individuals die in consequence. Forty million people are estimated to die because of M. tuberculosis over the next 25 years if the measures for controlling this infection are not extensively developed. In the vaccination field, BacillusCalmette–Guérin (BCG) is still the most effective vaccine but it shows no efficacy in adult pulmonary patients. One of the other problems regarding TB is its appropriate diagnosis.

Objectives:

In this experimental study, the recombinant cytochrome P450 CYP141 protein of M. tuberculosis was expressed and purified to be used as a vaccine candidate and diagnostic purpose in subsequent investigations.

Materials and Methods:

The optimization of the cytochrome P450 CYP141 protein expression was evaluated in different conditions. Then, this protein was purified with a resin column of nickel–nitrilotriacetic acid and investigated via Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) and Western Blotting.

Results:

The highest expression of the cytochrome P450 CYP141 protein was obtained by the addition of 1 mM of isopropyl β-D-1-thiogalactopyranoside (IPTG) to the bacterial culture grown to an optical density at 600 nm (OD600) of 0.6, 16 hours after induction. This protein was subsequently purified with a purification of higher than 80%. The results of Western Blotting indicated that the purified protein was specifically detected.

Conclusions:

In this experimental study, for the first time in Iran the expression and purification of this recombinant protein was done successfully. This recombinant protein could be used as a vaccine candidate and diagnostic purpose in subsequent investigations.

Structural and functional characterization of a ketosteroid transcriptional regulator of Mycobacterium tuberculosis

Catabolism of host cholesterol is critical to the virulence of Mycobacterium tuberculosis and is a potential target for novel therapeutics. KstR2, a TetR family repressor (TFR), regulates the expression of 15 genes encoding enzymes that catabolize the last half of the cholesterol molecule, represented by 3aα-H-4α(3'-propanoate)-7aβ-methylhexahydro-1,5-indane-dione (HIP). Binding of KstR2 to its operator sequences is relieved upon binding of HIP-CoA. A 1.6-Å resolution crystal structure of the KstR2(Mtb)·HIP-CoA complex reveals that the KstR2(Mtb) dimer accommodates two molecules of HIP-CoA. Each ligand binds in an elongated cleft spanning the dimerization interface such that the HIP and CoA moieties interact with different KstR2(Mtb) protomers. In isothermal titration calorimetry studies, the dimer bound 2 eq of HIP-CoA with high affinity (K(d) = 80 ± 10 nm) but bound neither HIP nor CoASH. Substitution of Arg-162 or Trp-166, residues that interact, respectively, with the diphosphate and HIP moieties of HIP-CoA, dramatically decreased the affinity of KstR2(Mtb) for HIP-CoA but not for its operator sequence. The variant of R162M that decreased the affinity for HIP-CoA (ΔΔG = 13 kJ mol(-1)) is consistent with the loss of three hydrogen bonds as indicated in the structural data. A 24-bp operator sequence bound two dimers of KstR2. Structural comparisons with a ligand-free rhodococcal homologue and a DNA-bound homologue suggest that HIP-CoA induces conformational changes of the DNA-binding domains of the dimer that preclude their proper positioning in the major groove of DNA. The results provide insight into KstR2-mediated regulation of expression of steroid catabolic genes and the determinants of ligand binding in TFRs.

Mechanistic insight into the enzymatic reduction of truncated hemoglobin N of Mycobacterium tuberculosis: role of the CD loop and pre-A motif in electron cycling

Many pathogenic microorganisms have evolved hemoglobin-mediated nitric oxide (NO) detoxification mechanisms, where a globin domain in conjunction with a partner reductase catalyzes the conversion of toxic NO to innocuous nitrate. The truncated hemoglobin HbN of Mycobacterium tuberculosis displays a potent NO dioxygenase activity despite lacking a reductase domain. The mechanism by which HbN recycles itself during NO dioxygenation and the reductase that participates in this process are currently unknown. This study demonstrates that the NADH-ferredoxin/flavodoxin system is a fairly efficient partner for electron transfer to HbN with an observed reduction rate of 6.2 μM/min(-1), which is nearly 3- and 5-fold faster than reported for Vitreoscilla hemoglobin and myoglobin, respectively. Structural docking of the HbN with Escherichia coli NADH-flavodoxin reductase (FdR) together with site-directed mutagenesis revealed that the CD loop of the HbN forms contacts with the reductase, and that Gly(48) may have a vital role. The donor to acceptor electron coupling parameters calculated using the semiempirical pathway method amounts to an average of about 6.4 10(-5) eV, which is lower than the value obtained for E. coli flavoHb (8.0 10(-4) eV), but still supports the feasibility of an efficient electron transfer. The deletion of Pre-A abrogated the heme iron reduction by FdR in the HbN, thus signifying its involvement during intermolecular interactions of the HbN and FdR. The present study, thus, unravels a novel role of the CD loop and Pre-A motif in assisting the interactions of the HbN with the reductase and the electron cycling, which may be vital for its NO-scavenging function.

Mechanism of dephosphorylation of glucosyl-3-phosphoglycerate by a histidine phosphatase

Mycobacterium tuberculosis (Mtb) synthesizes polymethylated polysaccharides that form complexes with long chain fatty acids. These complexes, referred to as methylglucose lipopolysaccharides (MGLPs), regulate fatty acid biosynthesis in vivo, including biosynthesis of mycolic acids that are essential for building the cell wall. Glucosyl-3-phosphoglycerate phosphatase (GpgP, EC 5.4.2.1), encoded by Rv2419c gene, catalyzes the second step of the pathway for the biosynthesis of MGLPs. The molecular basis for this dephosphorylation is currently not understood. Here, we describe the crystal structures of apo-, vanadate-bound, and phosphate-bound MtbGpgP, depicting unliganded, reaction intermediate mimic, and product-bound views of MtbGpgP, respectively. The enzyme consists of a single domain made up of a central β-sheet flanked by α-helices on either side. The active site is located in a positively charged cleft situated above the central β-sheet. Unambiguous electron density for vanadate covalently bound to His(11), mimicking the phosphohistidine intermediate, was observed. The role of residues interacting with the ligands in catalysis was probed by site-directed mutagenesis. Arg(10), His(11), Asn(17), Gln(23), Arg(60), Glu(84), His(159), and Leu(209) are important for enzymatic activity. Comparison of the structures of MtbGpgP revealed conformational changes in a key loop region connecting β1 with α1. This loop regulates access to the active site. MtbGpgP functions as dimer. L209E mutation resulted in monomeric GpgP, rendering the enzyme incapable of dephosphorylation. The structures of GpgP reported here are the first crystal structures for histidine-phosphatase-type GpgPs. These structures shed light on a key step in biosynthesis of MGLPs that could be targeted for development of anti-tuberculosis therapeutics.

Mycobacterium tuberculosis as a sarcoid factor? A case report of family sarcoidosis

PATIENT

Male, 26 FINAL DIAGNOSIS: Sarcoidosis Symptoms: Disseminated lung parenchymal changes Medication: - Clinical Procedure: - Specialty: Pulmonology.

OBJECTIVE

Rare disease.

BACKGROUND

Sarcoidosis is a granulomatous inflammatory disease that is induced by unknown antigen(s) in a genetically susceptible host. Although the direct link between Mycobacterium tuberculosis (MTB) infection and sarcoidosis can be excluded on the basis of a current knowledge, the non-infectious mechanisms may explain the causative role of mycobacterial antigens. The co-incidence of tuberculosis (TB) and sarcoidosis, and higher incidence of mycobacterial DNA in biological samples of sarcoid patients, have been reported by many authors.

CASE REPORT

We present a case in which MTB infection in 1 family member triggered a sarcoid reaction in the infected subject and 2 other non-infected family members. We discuss different aspects of diagnosis and differentiation, as well as up-to-date hypotheses on the possible mechanisms leading to sarcoid inflammation in patients exposed to MTB.

CONCLUSIONS

This case series documents the possibility of familial spreading of sarcoidosis, and points to MTB as a potential etiological factor.

Mycobacterium tuberculosis phosphoenolpyruvate carboxykinase is regulated by redox mechanisms and interaction with thioredoxin

Tuberculosis remains a major health concern worldwide. Eradication of its causative agent, the bacterial pathogen Mycobacterium tuberculosis, is particularly challenging due to a vast reservoir of latent carriers of the disease. Despite the misleading terminology of a so-called dormant state associated with latent infections, the bacteria have to maintain basic metabolic activities. Hypoxic conditions have been widely used as an in vitro system to study this dormancy. Such studies identified a rearrangement of central carbon metabolism to exploit fermentative processes caused by the lack of oxygen. Phosphoenolpyruvate carboxykinase (Pck; EC 4.1.1.32) is the enzyme at the center of these metabolic rearrangements. Although Pck is associated with gluconeogenesis under standard growth conditions, the enzyme can catalyze the reverse reaction, supporting anaplerosis of the tricarboxylic acid cycle, under conditions leading to slowed or stopped bacterial replication. To study the mechanisms that regulate the switch between two Pck functions, we systematically investigated factors influencing the gluconeogenic and anaplerotic reaction kinetics. We demonstrate that a reducing environment, as found under hypoxia-triggered non-replicating conditions, accelerates the reaction in the anaplerotic direction. Furthermore, we identified proteins that interact with Pck. The interaction between Pck and the reduced form of mycobacterial thioredoxin, gene expression of which is increased under hypoxic conditions, also increased the Pck anaplerotic activity. We thus propose that a reducing environment and the protein-protein interaction with thioredoxin in particular enable the Pck anaplerotic function under fermentative growth conditions.

Optimization of SABRE for polarization of the tuberculosis drugs pyrazinamide and isoniazid

Hyperpolarization produces nuclear spin polarization that is several orders of magnitude larger than that achieved at thermal equilibrium thus providing extraordinary contrast and sensitivity. As a parahydrogen induced polarization (PHIP) technique that does not require chemical modification of the substrate to polarize, Signal Amplification by Reversible Exchange (SABRE) has attracted a lot of attention. Using a prototype parahydrogen polarizer, we polarize two drugs used in the treatment of tuberculosis, namely pyrazinamide and isoniazid. We examine this approach in four solvents, methanol-d4, methanol, ethanol and DMSO and optimize the polarization transfer magnetic field strength, the temperature as well as intensity and duration of hydrogen bubbling to achieve the best overall signal enhancement and hence hyperpolarization level.

Rapid detection of rpoB mutations in rifampin resistant M. tuberculosis from sputum samples by denaturing gradient gel electrophoresis

OBJECTIVE

To establish a rapid detection method for identifying rpoB mutations associated with rifampin (RIF) resistance in sputum specimens.

METHODS

We detected rpoB mutations directly in 90 sputum specimens collected from suspected tuberculosis patients using PCR-based denaturing gradient gel electrophoresis (DGGE) and compared these results with those obtained by rpoB sequencing and conventional drug susceptibility testing.

RESULTS

The positive detection rate of Mycobacterium tuberculosis (M. tuberculosis) was 52.2% by Acid-Fast Bacilli staining and 72.2% by conventional mycobacterial culture. In contrast, the positive rate was significantly higher (93.3%) by PCR-based detection of the rpoB gene in the same specimens. Furthermore, 75% of the tested specimens presented abnormal patterns compared with the wild-type pattern (standard H37Rv strain) analysed by DGGE. A total of 12 different patterns, representing 12 different rpoB mutations, were observed in the 63 abnormal patterns. The match rate of rpoB mutations detected by DGGE reached 96.9% when compared to DNA sequencing.

CONCLUSION

Our findings indicate that PCR-based DGGE is a rapid and reliable bio-technique for direct detection of rpoB mutations associated with RIF resistance in the sputum of suspected tuberculosis patients.