Tuberculosis: a focused review for the emergency medicine clinician

Insights, beliefs, and myths surrounding tuberculosis among pulmonary patients with delayed healthcare access in a high-burden TB state in Nigeria - a qualitative inquiry

Introduction

Nigeria grapples with a substantial burden of tuberculosis (TB), particularly in Oyo State, designated as a high-burden State for TB. Effectively addressing this persistent health challenge necessitates more than just medical interventions; it requires a profound understanding of the diverse insights, beliefs, and myths held by TB patients.

Methods

This qualitative study explores the perspectives of pulmonary TB patients with delayed healthcare access in Oyo State, Nigeria, focusing on their beliefs, and conceptions. In-depth interviews were conducted with 25 TB patients and 20 healthcare providers.

Results

Thematic analysis of patients' responses revealed a complex interplay between cultural, spiritual, and biomedical insights. These challenges questioned the germ theory, associating TB with witchcraft and spiritual attacks. Beliefs in hereditary transmission, links between tobacco use and health outcomes, and uncertainties about infection nature underscored disparities influenced by socio-economic factors. Insights into transmission ideas, preventive measures, and treatment beliefs highlighted a blend of culturally influenced and scientifically supported strategies. Healthcare providers' insights emphasized the necessity for targeted health education.

Discussion

These findings contribute to a nuanced understanding of TB perceptions, emphasizing the importance of culturally sensitive interventions to enhance awareness and promote timely and accurate health-seeking behaviors.

Calcitriol supplementation accelerates the recovery of patients with tuberculosis who have vitamin D deficiency: a randomized, single-blind, controlled clinical trial

Background

This study aimed to evaluate whether calcitriol supplementation enhances CD4⁺ T cell count and prognosis in patients with tuberculosis and low 25(OH)D levels.

Methods

This randomized controlled clinical trial enrolled treatment-naïve patients with tuberculosis admitted to Zigong First People’s Hospital (June 2016 to April 2017). The patients were grouped as the serum 25(OH)D ≥ 75 nmol/L (Normal-25(OH)D) and 25(OH)D < 75 nmol/L (Low-25(OH)D) groups. The Low-Vit-D group was randomized to the Low-25(OH)D and Low-25(OH)D-Calcitriol groups. All patients were treated with the 2HRZE/4HR regimen. The patients in the Low-25(OH)D-Calcitriol group received calcitriol 0.25 µg bid. The main endpoints were CD4⁺ T cell count during treatment, time to sputum culture conversion, time to 50% lesion absorption, and a 6-month cure rate.

Results

This study included 30 patients in each group. Baseline 25-(OH) D levels and CD4⁺ T cell counts were higher in the Normal-25(OH)D group than in the Low-25(OH)D and Low-25(OH)D-Calcitriol groups (25(OH)D: 79.3 ± 3.4 vs. 37.8 ± 13.4 vs. 11.9 nmol/L, P < 0.05; 671 ± 287 vs. 200 ± 110 vs. 194 ± 119 cell/µL, P < 0.05). 25-(OH) D levels and CD4⁺ T cell counts increased in the Low-25(OH)D-Calcitriol group during treatment to reach higher levels than in the Low-25(OH)D group at 1, 4, 8, and 24 weeks (all P < 0.05). Compared with the Low-25(OH)D group, the Low-25(OH)D-Calcitriol group showed shorter time to sputum culture conversion (3.2 ± 1.4 vs. 5.9 ± 2.5 days, P < 0.001) and time to 50% lesion absorption (7.4 ± 1.5 vs. 10.9 ± 4.0 days, P = 0.014) and similar to those in the Normal-25(OH)D group (3.1 ± 1.2 and 7.3 ± 1.5 days, respectively. The cure rate was 86.7% in the Low-25(OH)D group and 96.7% in the two other groups.

Conclusions

Calcitriol supplementation can elevate CD4⁺ T cell levels, shorten the time to sputum culture conversion, and accelerate lesion absorption in patients with tuberculosis and 25(OH)D deficiency.

Trial registration The study is registered at the Chinese Clinical Trial Registry (ChiCTR2000039832)

Emergency department screening for latent tuberculosis infection

OBJECTIVE

Approximately 12.4 million people in the U.S. have latent tuberculosis infection (LTBI), 73% of whom are non-U.S. born. Identification and treatment of LTBI are essential for tuberculosis eradication. We evaluated an emergency department (ED) - based LTBI screening and linkage to care program.

METHODS

We queried electronic records of a clinical prevention program located in a Midwestern, urban, academic ED that serves as the region's safety-net hospital. Program staff approached non-U.S. born ED patients from TB endemic areas. Patients received QuantiFERON-TB Gold Plus (QFT) blood testing and, if positive, were referred to treatment. The primary outcome was the proportion of tested patients newly diagnosed with LTBI. We secondarily report the number of patients linked to care who initiated LTBI treatment.

RESULTS

The program approached 33 patients, of whom 24 (72.7%) were eligible, and 23 (95.8%) were tested. The majority were male (13, 56.5%), median age was 33 years (IQR 27-45), and 13 (56.5%) were from Latin America. Three patients (13.0%, 95% CI 0.03-0.35) were newly diagnosed with LTBI and linked to care; two (66.7%) started LTBI treatment.

CONCLUSIONS

In this first report of an ED-based LTBI screening program implemented in a region with low TB prevalence, over 10% of high-risk ED patients tested positive for LTBI and were linked to treatment. Screening populations at risk for LTBI in EDs and linking them to public health treatment services should be prioritized in order to achieve TB elimination in the U.S.

Validation of Differentially Expressed Immune Biomarkers in Latent and Active Tuberculosis by Real-Time PCR

Tuberculosis (TB) remains a major global threat and diagnosis of active TB ((ATB) both extra-pulmonary (EPTB), pulmonary (PTB)) and latent TB (LTBI) infection remains challenging, particularly in high-burden countries which still rely heavily on conventional methods. Although molecular diagnostic methods are available, e.g., Cepheid GeneXpert, they are not universally available in all high TB burden countries. There is intense focus on immune biomarkers for use in TB diagnosis, which could provide alternative low-cost, rapid diagnostic solutions. In our previous gene expression studies, we identified peripheral blood leukocyte (PBL) mRNA biomarkers in a non-human primate TB aerosol-challenge model. Here, we describe a study to further validate select mRNA biomarkers from this prior study in new cohorts of patients and controls, as a prerequisite for further development. Whole blood mRNA was purified from ATB patients recruited in the UK and India, LTBI and two groups of controls from the UK (i) a low TB incidence region (CNTRLA) and (ii) individuals variably-domiciled in the UK and Asia ((CNTRLB), the latter TB high incidence regions). Seventy-two mRNA biomarker gene targets were analyzed by qPCR using the Roche Lightcycler 480 qPCR platform and data analyzed using GeneSpring™ 14.9 bioinformatics software. Differential expression of fifty-three biomarkers was confirmed between MTB infected, LTBI groups and controls, seventeen of which were significant using analysis of variance (ANOVA): CALCOCO2, CD52, GBP1, GBP2, GBP5, HLA-B, IFIT3, IFITM3, IRF1, LOC400759 (GBP1P1), NCF1C, PF4V1, SAMD9L, S100A11, TAF10, TAPBP, and TRIM25. These were analyzed using receiver operating characteristic (ROC) curve analysis. Single biomarkers and biomarker combinations were further assessed using simple arithmetic algorithms. Minimal combination biomarker panels were delineated for primary diagnosis of ATB (both PTB and EPTB), LTBI and identifying LTBI individuals at high risk of progression which showed good performance characteristics. These were assessed for suitability for progression against the standards for new TB diagnostic tests delineated in the published World Health Organization (WHO) technology product profiles (TPPs).

Comparative analysis between tuberculous meningitis and other forms of extrapulmonary tuberculosis

Introduction

Tuberculosis is a multisystem disease that may affect any organ or tissue. Tuberculous meningitis (TBM) is the most severe form of tuberculosis and commonly affects the brain. We aimed to study the epidemiological, clinical, therapeutic and evolutionary features of TBM among adults and to compare them with other forms of extrapulmonary tuberculosis.

Methods

We conducted a retrospective study including all patients hospitalized for extrapulmonary tuberculosis in the infectious disease department in Sfax, Tunisia between 1993 and 2018. We specified the particularities of TBM cases, and we compared them with other extrapulmonary tuberculosis cases.

Results

We encountered 78 patients diagnosed with TBM, among 519 patients with extrapulmonary tuberculosis (15%). The median age was 36 years (23-50) years. There were 44 females (56.4%). In comparison with other forms of extrapulmonary tuberculosis, fever [odds ratio (OR)=4.4; p<0.001], asthenia (OR=3.4; p<0.001) and anorexia (OR=2.3; p=0.001) were significantly more frequent in TBM patients. Adverse effects of antitubercular therapy were more frequent among TBM patients (OR=3.1; p<0.001). The mean duration of antitubercular therapy was 15 (12-20) months. Recovery occurred in 66 cases (84.6%), complications in 44 cases (56.4%) and death in 7 cases (9%). Comparison of the disease evolution showed that complications (OR=7.4; p<0.001) and mortality rates (OR=10.7; p<0.001) were significantly more frequent in TBM patients, while recovery was significantly more frequent in other sites of extrapulmonary tuberculosis patients (OR=0.5; p=0.02).

Conclusions

In our country, TBM remains a disabling disease. Despite antitubercular therapy, the prognosis was more severe with the occurrence of not only complications but also a high mortality rate in comparison with other forms of extrapulmonary tuberculosis. When clinical and laboratory features suggest the diagnosis of TBM, clinicians should look for tuberculosis elsewhere in the body.

A Glutamine Insertion at Codon 432 of RpoB Confers Rifampicin Resistance in Mycobacterium tuberculosis

Tuberculosis (TB) is an infectious respiratory disease caused by Mycobacterium tuberculosis and one of the top 10 causes of death worldwide. Treating TB is challenging; successful treatment requires a long course of multiple antibiotics. Rifampicin (RIF) is a first-line drug for treating TB, and the development of RIF-resistant M. tuberculosis makes treatment even more difficult. To determine the mechanism of RIF resistance in these strains, we searched for novel mutations by sequencing. Four isolates, CDC-1, CDC-2, CDC-3, and CDC-4, had high-level RIF resistance and unique mutations encoding RpoB G¹⁵⁸R, RpoB V¹⁶⁸A, RpoB S¹⁸⁸P, and RpoB Q⁴³²insQ, respectively. To evaluate their correlation with RIF resistance, plasmids carrying rpoB genes encoding these mutant proteins were transfected into the H₃₇Rv reference strain. The plasmid complementation of RpoB indicated that G¹⁵⁸R, V¹⁶⁸A, and S¹⁸⁸P did not affect the MIC of RIF. However, the MIC of RIF was increased in H₃₇Rv carrying RpoB Q⁴³²insQ. To confirm the correlation between RIF resistance and Q⁴³²insQ, we cloned an rpoB fragment carrying the insertion (encoding RpoB Q⁴³²insQ) into H₃₇Rv by homologous recombination using a suicide vector. All replacement mutants expressing RpoB Q⁴³²insQ were resistant to RIF (MIC > 1 mg/L). These results indicate that RpoB Q⁴³²insQ causes RIF resistance in M. tuberculosis.

Gene network in pulmonary tuberculosis based on bioinformatic analysis

BACKGROUND

Pulmonary tuberculosis (PTB) is one of the serious infectious diseases worldwide; however, the gene network involved in the host response remain largely unclear.

METHODS

This study integrated two cohorts profile datasets GSE34608 and GSE83456 to elucidate the potential gene network and signaling pathways in PTB. Differentially expressed genes (DEGs) were obtained for Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis using Metascape database. Protein-Protein Interaction (PPI) network of DEGs was constructed by the online database the Search Tool for the Retrieval of Interacting Genes (STRING). Modules were identified by the plug-in APP Molecular Complex Detection (MCODE) in Cytoscape. GO and KEGG pathway of Module 1 were further analyzed by STRING. Hub genes were selected for further expression validation in dataset GSE19439. The gene expression level was also investigated in the dataset GSE31348 to display the change pattern during the PTB treatment.

RESULTS

Totally, 180 shared DEGs were identified from two datasets. Gene function and KEGG pathway enrichment revealed that DEGs mainly enriched in defense response to other organism, response to bacterium, myeloid leukocyte activation, cytokine production, etc. Seven modules were clustered based on PPI network. Module 1 contained 35 genes related to cytokine associated functions, among which 14 genes, including chemokine receptors, interferon-induced proteins and Toll-like receptors, were identified as hub genes. Expression levels of the hub genes were validated with a third dataset GSE19439. The signature of this core gene network showed significant response to Mycobacterium tuberculosis (Mtb) infection, and correlated with the gene network pattern during anti-PTB therapy.

CONCLUSIONS

Our study unveils the coordination of causal genes during PTB infection, and provides a promising gene panel for PTB diagnosis. As major regulators of the host immune response to Mtb infection, the 14 hub genes are also potential molecular targets for developing PTB drugs.

Practical recommendations for critical care and anesthesiology teams caring for novel coronavirus (2019-nCoV) patients

A global health emergency has been declared by the World Health Organization as the 2019-nCoV outbreak spreads across the world, with confirmed patients in Canada. Patients infected with 2019-nCoV are at risk for developing respiratory failure and requiring admission to critical care units. While providing optimal treatment for these patients, careful execution of infection control measures is necessary to prevent nosocomial transmission to other patients and to healthcare workers providing care. Although the exact mechanisms of transmission are currently unclear, human-to-human transmission can occur, and the risk of airborne spread during aerosol-generating medical procedures remains a concern in specific circumstances. This paper summarizes important considerations regarding patient screening, environmental controls, personal protective equipment, resuscitation measures (including intubation), and critical care unit operations planning as we prepare for the possibility of new imported cases or local outbreaks of 2019-nCoV. Although understanding of the 2019-nCoV virus is evolving, lessons learned from prior infectious disease challenges such as Severe Acute Respiratory Syndrome will hopefully improve our state of readiness regardless of the number of cases we eventually manage in Canada.