Smoking and tuberculosis: the epidemiological association and immunopathogenesis

Relationship between smoking and tuberculosis recurrence: A systematic review and meta-analysis

INTRODUCTION

Of the problems in tuberculosis (TB) control program is the recurrence of this disease. In some studies, smoking has been reported as the most important risk factor. Therefore, the present study aimed at examining the association between smoking and tuberculosis recurrence using meta-analysis.

METHODS

To report the findings of this meta-analysis, we used PRISMA. The protocol of this study has been recorded in PROSPERO. The research question has been formulated based on PICO, and the search was performed using both MeSH and non-MeSH keywords. After screening and selecting the articles and evaluating their quality using the NOS checklist, the overall estimate of the odds ratio of tuberculosis recurrence in smokers was assessed with a 95% confidence interval.

RESULTS

Fourteen studies met the inclusion criteria. The total number of samples in the group of patients with tuberculosis recurrence was 1988 with 855 (43%) smokers, and in the group of patients affected by tuberculosis without recurrence, it was 27,226 with 7503 (27.56%) smokers. In 13 studies, the odds ratio of tuberculosis recurrence was higher in smokers; this difference was statistically significant in 12 of them. Combining the results of these 14 studies, the odds ratio of tuberculosis recurrence in smokers was 2.10 times higher, using the random effects model (95% CI:1.69, 2.61).

CONCLUSION

Based on the results of study present, smoking increases the risk of tuberculosis recurrence. Therefore, to eradicate tuberculosis by 2030, more serious interventions should be taken to quit smoking, which in turn reduces the incidence of tuberculosis.

Predictors of tuberculosis disease in smokers: a case-control study in northeastern Malaysia

Objective

Tuberculosis (TB) is a leading infectious disease. However, many TB cases remain undetected and only present symptoms at a late stage of the infection. Therefore, targeted TB screening in high-risk populations, including smokers, is crucial. This study aimed to determine the predictors of TB disease among the smoker population in northeast Malaysia from 2019 to 2020.

Methods

A case-control study was conducted involving smokers aged 18 years and older from health clinics in Bachok Kelantan, Malaysia. Data were collected via face-to-face interviews or telephone calls from 159 participants, randomly selected from outpatient TB records. Simple and multiple logistic regression, using R software, were used to identify the determinants of TB.

Results

Most participants were male (59.1%) and had a secondary education (56.0%). Active smokers constituted 35.2% of the group, and the mean (SD) duration of exposure to smoking was 23.9 (16.47) and 18.4 (12.84) years for the case and control groups, respectively. Being an ex-smoker (adjusted odds ratio (AOR) 6.17; 95% CI [1.55-28.32]; p = 0.013), weight loss (AOR 13.45; 95% CI [4.58-44.46]; p < 0.005), night sweats (AOR 63.84; 95% CI [8.99-1392.75]; p < 0.005) and duration of symptoms (AOR 1.02; 95% CI [1.01-1.04]; p = 0.022) were shown to be significant predictors for TB disease.

Conclusion

Four predictors of TB disease in the population of smokers were recognised in this study and should be prioritised for early TB screening and diagnosis. This may help increase TB detection, initiate prompt treatment and reduce complications among the group at risk for TB.

P2X7 1513A/C loss-of-function polymorphism and active tuberculosis disease in a cohort of Egyptian population: a pilot study

Background

Tuberculosis (TB) is a multifactorial disease, and increasing evidence shows that genetic variants in regulating genes of immune response confer susceptibility to active TB at the individual level. We aimed to identify the contribution of P2X7 receptor 1513A/C genetic polymorphisms to different clinical forms of active tuberculosis in a cohort of Egyptian population.

Methods

A case–control study that enrolled 25 newly diagnosed pulmonary TB (PTB) patients by positive sputum for AFB or positive culture, 25 extrapulmonary TB (EPTB) diagnosed by pathological/bacteriological/immunological studies and 25 healthy controls. A blood sample was taken before starting of therapy for P2X7 1513A/C polymorphism genotyping using PCR-restriction fragment length polymorphism.

Results

Fifty-two percent of the participants were in the third decade with equal gender distribution. P2X7 receptor 1513AA (homozygote wild), AC (heterozygote) and CC (homozygote mutant) genotypes were identified. AC and CC genotypes distribution were significantly more frequent in the active TB cases (either PTB or EPTB) rather than controls (p < 0.05). Further, P2X7 1513A/C genotypes’ distribution did not associate with old TB or gender (p > 0.05), but significantly associated with history of smoking (x2 trend analysis p = 0.036).

Conclusions

There is positive association between P2X7 receptor 1513A/C polymorphism and active tuberculosis in the Egyptians.

Nicotine associates to intracellular Mycobacterium tuberculosis inducing genes related with resistance to antimicrobial peptides

Tobacco consumption is related to an increased risk to develop tuberculosis. Antimicrobial peptides are essential molecules in the response to Mycobacterium tuberculosis (Mtb) because of their direct antimicrobial activity. The aim of this study was to demonstrate that nicotine enters into Mtb infected epithelial cells and associates with the mycobacteria inducing genes related to antimicrobial peptides resistance. Epithelial cells were infected with virulent Mtb, afterwards cells were stimulated with nicotine. The internalization of nicotine was followed using electron and confocal microscopy. The lysX expression was evaluated isolating mycobacterial RNA and submitted to RT-PCR analysis. Our results indicated that nicotine promotes Mtb growth in a dose-dependent manner in infected cells. We also reported that nicotine induces lysX expression. In conclusion, nicotine associates to intracellular mycobacteria promoting intracellular survival.

Lifestyle Risk Factors Associated with Tuberculosis Patients in Asir Region of Saudi Arabia

Background:

Tuberculosis remains to be a major public health problem. Lifestyle factors that have indirectly influence to the burden of tuberculosis. The aim of this study is to determine the lifestyle risk factors associated with tuberculosis patients in Asir region of KSA.

Methods:

We conducted a case-control study at the military hospital of Asir region of KSA. A total of 135 sample which is divided into 67 cases and 67 controls. Cases were included from hospital database between 2017 and 2018. Control were selected from patient attending the same hospital with respiratory disease other than tuberculosis. Data collection done through interview using a structured questionnaire. Lifestyle factors and socio-demographic factors associated with tuberculosis were analyzed using logistic regression.

Results:

Mean age of study participants (cases and control) are 38.04 ± 9.66 and 40.16 ± 7.72 respectively. Most important factors associated with tuberculosis patients are overweight and obese [OR = 4.40, 95% CI 1.27-15.25 and 2.38 (1.61-9.22)], Smoker [OR = 1.34, 95% CI 0.52-3.43], abnormal sleep at night (<8 hours) [OR = 5.03, 95% CI 1.57-16.10], blue color job worker [OR = 2.69, 95% CI 1.02-7.28], physical exercise <3 days/week [OR = 1.41, 95% CI 1.21-3.47].

Conclusions:

In Saudi Arabia, a person's lifestyle and socioeconomic condition are associated with tuberculosis. Interventions focused on improving the quality of life through a reduction of risky lifestyle which prevent the spread of Tuberculosis in Saudi society and improve the efficiency of Saudi national tuberculosis control programme.

Clinico-radiological particularities of common pulmonary tuberculosis among smokers in Tunisia

INRODUCTION

Smoking and tuberculosis are two major public health issues worldwide, particularly in emerging countries. Currently, the relationship between these two scourges is well established.

AIM

Describe the clinical, radiological and progressive features of common pulmonary tuberculosis in smokers.

METHODS

Comparative study, carried out at the Pneumology department of the Hédi Chaker in Sfax, Tunisia, including 120 patients hospitalized for common pulmonary tuberculosis  from January 2014 to December 2016 and who completed their follow-ups for a minimum period of 2 years . The patients were divided into 2 groups: Group1 (G1) consisting of 60 smoking patients and Group 2 (G2) consisting of 60 non-smoking patients. To assess the severity of radiological lesions, we used the International Labour Organization classification for simple pneumoconiosis and the Brouet classification.

RESULTS

The mean age of the patients was comparable in the two groups with a predominance of male for G1 (91%) and female for G2 (70%). The smokers consulted later (113 days versus 60 days (p=0.023). Dyspnea, hemoptysis and chest pain were significantly more frequent in the smokers. The radiological lesions were more serious in smoking group. Bilateral lesions were more observed in smokers (58% vs 25% p = 0.004). A positive association was noted between the extent of radiological lesions, stage 3 and 4 according to the Brouet classification, and smoking status (p <0.001). Similarly for the International Labour Organization classification for simple pneumoconiosis , the radiological lesions were more severe (scores 6 - 15) in the smokers (p <0.001).Smoking was associated with poor adherence (p <0.008), prolonged anti-tuberculosis treatment (p <0.001), delayed RBK negativation in sputum (p <0.001), and more frequent reactivation of tuberculosis (p=0.001). After the diagnosis of CPT, 83% of patients continued to smoke at the same rate and only 7% of patients had quit smoking.

CONCLUSION

Smoking worsens CPT by making the clinical picture noisier, radiological lesions more aggressive, negativation of BK in sputum later, and reactivation of CPT more frequent.

The effect of smoking on latent tuberculosis infection susceptibility in high risk individuals in Iran

Tuberculosis has been declared as a global emergency. Latent tuberculosis infection (LTBI) is a state in which host immunity cannot completely eradicate Mycobacterium tuberculosis. Cigarette smoke increases the risk of respiratory infections, such a TB, as it has adverse effects on respiratory immune function. In this cross-sectional study, which was performed from 2016 to 2017, 31 patients with newly diagnosed lung cancer, 63 Chronic obstructive pulmonary disease (COPD), 46 with problems in respiratory system, and 40 healthy subjects were studied. Demographic data of all subjects were recorded via a questionnaire. IGRAs (Interferon-γ release assays) were used to determine LTBI. We showed that smoking has significant odds ratio for COPD patients (OR: 4.58, 95% CI: 1.93-10.87). Also, the concordance of smoking with COPD (OR: 22, 95% CI: 2.7-179.2), lung cancer (OR: 10, 95% CI: 1.03-97), and other respiratory diseases (OR: 4.54, 95% CI: 1.93-10.87) is a significant risk factor for the presence of LTBI whereas the existence of LTBI in the study groups did not show any significant odds ratio. This study is the first to analyze the relationship between smoking in patients with respiratory diseases and LTBI susceptibility in Iran by IGRAs, which proposes cigarette smoking as a powerful risk factor for LTBI.

Divergent Effect of Cigarette Smoke on Innate Immunity in Inflammatory Bowel Disease: A Nicotine-Infection Interaction

Cigarette smoke (CS) has adverse effects in patients with Crohn’s disease (CD), an inflammatory bowel disease (IBD) that has been associated with microbial infection, immuno-dysregulation, and mucosal dysfunction. However, CS seems to provide relief and protection to patients with another IBD known as ulcerative colitis (UC). These two subsets are featured as M1- and M2-mediated responses, respectively. Nicotine is the most active, addictive, and studied ingredient in CS. The mechanism of how nicotine and/or other CS ingredients induce pro-inflammatory or anti-inflammatory phenotypes in IBD patients remains under investigation. Our most recent in vitro nicotine study provided significant insights toward understanding the contradictory effects of nicotine on IBD patients, and it elucidated the mechanistic role of α7nAChR in modulation of macrophages in tobacco smokers. Shifting the beneficial effect of nicotine to a harmful outcome in CD patients was linked to a nicotine-microbe interaction that supports a microbial etiology in CD pathogenesis. Among the most debated pathogens in CD etiology is Mycobacterium avium subspecies paratuberculosis (MAP). Other studies associated nicotine with upregulation of miR-124 expression in macrophages, which led to anti-inflammatory response. This review discusses published work on the role of nicotine in modulation of the innate immune response and subsequent signaling in macrophages in IBD subsets.

Predictive value of TNF-α, IFN-γ, and IL-10 for tuberculosis among recently exposed contacts in the United States and Canada

BACKGROUND

We examined cytokine immune response profiles among contacts to tuberculosis patients to identify immunologic and epidemiologic correlates of tuberculosis.

METHODS

We prospectively enrolled 1272 contacts of culture-confirmed pulmonary tuberculosis patients at 9 United States and Canadian sites. Epidemiologic characteristics were recorded. Blood was collected and stimulated with Mycobacterium tuberculosis culture filtrate protein, and tumor necrosis factor (TNF-α), interferon gamma (IFN-γ), and interleukin 10 (IL-10) concentrations were determined using immunoassays.

RESULTS

Of 1272 contacts, 41 (3.2%) were diagnosed with tuberculosis before or < 30 days after blood collection (co-prevalent tuberculosis) and 19 (1.5%) during subsequent four-year follow-up (incident tuberculosis). Compared with contacts without tuberculosis, those with co-prevalent tuberculosis had higher median baseline TNF-α and IFN-γ concentrations (in pg/mL, TNF-α 129 versus 71, P < .01; IFN-γ 231 versus 27, P < .001), and those who subsequently developed incident tuberculosis had higher median baseline TNF-α concentrations (in pg/mL, 257 vs. 71, P < .05). In multivariate analysis, contact age < 15 years, US/Canadian birth, and IFN or TNF concentrations > the median were associated with co-prevalent tuberculosis (P < .01 for each); female sex (P = .03) and smoking (P < .01) were associated with incident tuberculosis. In algorithms combining young age, positive skin test results, and elevated CFPS TNF-α, IFN-γ, and IL-10 responses, the positive predictive values for co-prevalent and incident tuberculosis were 40 and 25%, respectively.

CONCLUSIONS

Cytokine concentrations and epidemiologic factors at the time of contact investigation may predict co-prevalent and incident tuberculosis.

THE ROLE OF CIGARETTE SMOKING AND ALCOHOL CONSUMPTION IN PULMONARY TUBERCULOSIS DEVELOPMENT AND RECURRENCE

During a two-year period (2001-2003), 464 patients were treated for tuberculosis at Jordanovac Department for Lung Diseases in Croatia. Besides pulmonary tuberculosis in 97.7% of patients, patients were also treated for tuberculous pleurisy (0.9%), tuberculous laryngitis (0.6%), tuberculous meningitis (0.2%), tuberculous pericarditis (0.2%) and urogenital tuberculosis (0.4%). Out of the total number of patients, 57.3% declared themselves to be active smokers (men were predominant and made up to 80.8%) and 20.9% to be active alcohol consumers. Both risk factors, i.e. smoking and alcohol consumption, were present in 15.1% of all patients. The most common comorbidities were diabetes mellitus (30.4%), cardiac diseases (11.2%) and chronic obstructive pulmonary disease (8.0%). Lung carcinoma was the most common malignant disease (n=51), with Mycobacterium tuberculosis isolated in 33% of them. Seventy-two of 464 (15.5%) patients had recurrences of tuberculosis. Of these, 30.5% had one of the risk factors (20.8% were smokers and 9.7% consumed alcohol), while 32.5% of patients had both risk factors. In conclusion, cigarette smoking was proved to be the most significant risk factor for development of pulmonary tuberculosis and its recurrence.

Epidemiology of Tuberculosis in the United States

Although considerable progress has been made in reducing US tuberculosis incidence, the goal of eliminating the disease from the United States remains elusive. A continued focus on preventing new tuberculosis infections while also identifying and treating persons with existing tuberculosis infection is needed. Continued vigilance to ensure ongoing control of tuberculosis transmission remains key.

Nicotine modulates molecules of the innate immune response in epithelial cells and macrophages during infection with M. tuberculosis

Smoking increases susceptibility to becoming infected with and developing tuberculosis. Among the components of cigarette smoke, nicotine has been identified as the main immunomodulatory molecule; however, its effect on the innate immune system is unknown. In the present study, the effect of nicotine on molecules of the innate immune system was evaluated. Lung epithelial cells and macrophages were infected with Mycobacterium tuberculosis (Mtb) and/or treated with nicotine. The results show that nicotine alone decreases the expression of the Toll-like receptors (TLR)-2, TLR-4 and NOD-2 in all three cell types, as well as the production of the SP-D surfactant protein in type II pneumocytes. Moreover, it was observed that nicotine decreases the production of interleukin (IL)-6 and C-C chemokine ligand (CCL)5 during Mtb infection in epithelial cells (EpCs), whereas in macrophages derived from human monocytes (MDMs) there is a decrease in IL-8, IL-6, tumor necrosis factor (TNF)-α, IL-10, CCL2, C-X-C chemokine ligand (CXCL)9 and CXCL10 only during infection with Mtb. Although modulation of the expression of cytokines and chemokines appears to be partially mediated by the nicotinic acetylcholine receptor α7, blocking this receptor found no effect on the expression of receptors and SP-D. In summary, it was found that nicotine modulates the expression of innate immunity molecules necessary for the defense against tuberculosis.

"Stages of change, smoking behavior and acceptability of a textmessaging intervention for tobacco cessation among cigarette, dokha and shishasmokers: A qualitative research study."

OBJECTIVES

To explore: (A) the underlying motivators and barriers to smoking cessation among young Arabic speaking smokers and (B) to examine the suitability and preferences for tobacco cessation interventions (specifically text messages) and study the possibility of enrollment methods for a randomised controlled study using text messages as an intervention for tobacco cessation.

DESIGN

Qualitative research using focus group discussions and content analysis.

SETTINGS

Two universities, one of them is the first and foremost comprehensive national university in the United Arab Emirates (UAE). The third setting is the largest hospital in the UAE and the flagship institution for the public health system in the emirate of Abu Dhabi.

PARTICIPANTS

Six focus group discussions with a total of 57 participants. Forty-seven men and 10 women. Fifty-three of them were current smokers.

RESULTS

The analysis of six focus groups was carried out. Main themes arose from the data included: preferences for tobacco cessation interventions and acceptability and feasibility of text messaging as tobacco cessation intervention. Different motives and barriers for quitting smoking including shisha and dokha were explored.

CONCLUSION

Interventions using text messaging for smoking cessation have not been used in the Middle East and they could potentially be effective; however, tailoring and closely examining the content and acceptability of text messages to be used is important before the conduction of trials involving their use. Social media is perceived to be more effective and influential, with a higher level of penetration into communities of young smokers.

Urban airborne particle exposure impairs human lung and blood Mycobacterium tuberculosis immunity

RATIONALE

Associations between urban (outdoor) airborne particulate matter (PM) exposure and TB and potential biological mechanisms are poorly explored.

OBJECTIVES

To examine whether in vivo exposure to urban outdoor PM in Mexico City and in vitro exposure to urban outdoor PM2.5 (< 2.5 µm median aerodynamic diameter) alters human host immune cell responses to Mycobacterium tuberculosis.

METHODS

Cellular toxicity (flow cytometry, proliferation assay (MTS assay)), M. tuberculosis and PM2.5 phagocytosis (microscopy), cytokine-producing cells (Enzyme-linked immune absorbent spot (ELISPOT)), and signalling pathway markers (western blot) were examined in bronchoalveolar cells (BAC) and peripheral blood mononuclear cells (PBMC) from healthy, non-smoking, residents of Mexico City (n=35; 13 female, 22 male). In vivo-acquired PM burden in alveolar macrophages (AM) was measured by digital image analysis.

MEASUREMENTS AND MAIN RESULTS

In vitro exposure of AM to PM2.5 did not affect M. tuberculosis phagocytosis. High in vivo-acquired AM PM burden reduced constitutive, M. tuberculosis and PM-induced interleukin-1β production in freshly isolated BAC but not in autologous PBMC while it reduced constitutive production of tumour necrosis factor-alpha in both BAC and PBMC. Further, PM burden was positively correlated with constitutive, PM, M. tuberculosis and purified protein derivative (PPD)-induced interferon gamma (IFN-γ) in BAC, and negatively correlated with PPD-induced IFN-γ in PBMC.

CONCLUSIONS

Inhalation exposure to urban air pollution PM impairs important components of the protective human lung and systemic immune response against M. tuberculosis. PM load in AM is correlated with altered M. tuberculosis-induced cytokine production in the lung and systemic compartments. Chronic PM exposure with high constitutive expression of proinflammatory cytokines results in relative cellular unresponsiveness.

The health and social implications of household air pollution and respiratory diseases

Approximately three billion individuals are exposed to household air pollution (HAP) from the burning of biomass fuels worldwide. Household air pollution is responsible for 2.9 million annual deaths and causes significant health, economic and social consequences, particularly in low- and middle-income countries. Although there is biological plausibility to draw an association between HAP exposure and respiratory diseases, existing evidence is either lacking or conflicting. We abstracted systematic reviews and meta-analyses for summaries available for common respiratory diseases in any age group and performed a literature search to complement these reviews with newly published studies. Based on the literature summarized in this review, HAP exposure has been associated with acute respiratory infections, tuberculosis, asthma, chronic obstructive pulmonary disease, pneumoconiosis, head and neck cancers, and lung cancer. No study, however, has established a causal link between HAP exposure and respiratory disease. Furthermore, few studies have controlled for tobacco smoke exposure and outdoor air pollution. More studies with consistent diagnostic criteria and exposure monitoring are needed to accurately document the association between household air pollution exposure and respiratory disease. Better environmental exposure monitoring is critical to better separate the contributions of household air pollution from that of other exposures, including ambient air pollution and tobacco smoking. Clinicians should be aware that patients with current or past HAP exposure are at increased risk for respiratory diseases or malignancies and may want to consider earlier screening in this population.

Pediatric Tuberculosis in a Northeast State of Peninsular Malaysia: Diagnostic Classifications and Determinants

Objectives

We sought to determine the total proportion of pediatric tuberculosis cases, characterize tuberculosis by its anatomical location and pretreatment sputum smear status, and to determine the association of the sociodemographic and clinical factors with tuberculosis disease among pediatric patients in Kelantan from 2012 until 2015.

Methods

We conducted a comparative cross-sectional study between tuberculosis cases and tuberculosis contacts among pediatric patients using the Tuberculosis Information System as a source population. All notified cases that fulfilled the inclusion and exclusion criteria were included in the study. Descriptive statistics, simple and multiple logistic regressions were used for data analysis.

Results

Of 5412 tuberculosis cases, 456 (8.4%) were pediatric patients with a mean age of 15.9 years. The majority had the pulmonary form of tuberculosis (78.1%) followed by the extrapulmonary (14.9%) and pulmonary form with concomitant extrapulmonary (7.0%) forms. Of all pulmonary tuberculosis cases, 64.9% were sputum smear-positive, and 35.1% were sputum smear-negative. Among 322 pediatric patients with tuberculosis, the majority were Malay (90.7%), 8.4% were illiterate, and 79.5% resided in non-urban areas. Of all cases, 2.8% were HIV-positive, and 14.6% were cigarette smokers. Older age, Malay ethnicity, female gender, non-urban residence, good education level, and cigarette smoking were the significant associated factors for tuberculosis disease among pediatric patients with an adjusted odds ratio (aOR) of 1.41 (95% confidence interval (CI): 1.29–1.54; p < 0.001), 0.17 (95% CI: 0.07–0.44; p < 0.001), 1.88 (95% CI: 1.33–2.65; p < 0.001), 1.92 (95% CI: 1.33–2.79; p = 0.001), 0.20 (95% CI: 0.12–0.33; p < 0.001), and 3.35 (95% CI: 1.86–6.01; p < 0.001), respectively.

Conclusions

The study will assist practices of tuberculosis detection and control management in the local setting and may help other national tuberculosis programs to review their detection criteria with similar statistics.

Prevalence of Tuberculosis Risk Factors among Bacteriologically Negative and Bacteriologically Confirmed Tuberculosis Patients from Five Regional Referral Hospitals in Uganda

Understanding risk factors for tuberculosis (TB) and their prevalence helps guide early diagnosis. We determined their prevalence among bacteriologically negative and bacteriologically confirmed TB patients in five regional referral hospitals in Uganda. This cross-sectional study considered 1,862 adult presumptive TB participants. We performed fluorescent microscopy, Xpert MTB/RIF (Xpert), Lowenstein-Jensen culture, human immunodeficiency virus, and random blood sugar testing on recruited patients. Prevalence and prevalence ratios of risk factors were compared among bacteriologically negative and confirmed cases. Odds ratios and 95% confidence interval (CI) were determined for significant risk factors in bacteriologically confirmed patients. Of the 1,862 participants, 978 (55%) were male and the median age of the participants was 36 years (interquartile range: 27-48). Up to 273 (15%) had a positive result on all three TB tests. Most prevalent risk factors (prevalence ratio [PR] > 1.0) among bacteriologically negative and positive TB patients were cigarette smoking (9.3% versus 2.1%; PR = 2.1), biosmoke (24% versus 39.7%; PR = 1.7), contact (4.2% versus 6.5%; PR = 1.6), male gender (51.4% versus 72.5%; PR = 1.4), alcohol use (17.2% versus 24.4%; PR = 1.4), diabetes (0.7% versus 0.9%; PR = 1.3), and family history of TB (12.1% versus 13.7%; PR = 1.1). The risk factors and their adjusted prevalence rate ratios (95% CI) of being bacteriologically positive were male (1.8 [1.4-2.4]), biosmoke exposure (1.5 [1.2-2.0]), and history of cigarette smoking (1.6 [1.1-2.4]). Among bacteriologically confirmed patients in Uganda, cigarette smoking, biosmoke exposure, contact, male gender, alcohol use, diabetes, and family history of TB are important risk factors for TB. Interventions for TB control in people with these risk factors would help in TB control efforts.

18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for Assessing Treatment Response of Pulmonary Multidrug-Resistant Tuberculosis

Background: The purpose of this prospective study was to evaluate the role of ¹⁸F-Fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) for assessing treatment response in patients with pulmonary multidrug-resistant tuberculosis (MDR-TB). Methods: The study subjects were four patients diagnosed with pulmonary MDR-TB who underwent MDR-TB treatment and serial ¹⁸F-FDG PET/CT at baseline and 6 and 12 months after treatment. The highest lung maximum standardized uptake value (SUV_max), average SUV_mean (average of all hypermetabolic parenchymal lesions), total metabolic lung volume (TMLV, sum of metabolic volumes from the hypermetabolic parenchymal lesions), and total lung glycolysis (TLG, sum of lesion glycolysis from the hypermetabolic parenchymal lesions) were determined as representative quantitative PET parameters for each patient. Results: All patients except one had negative sputum culture conversion after one month of treatment and achieved successful treatment outcomes. Baseline TMLV and TLG PET parameters were much higher in the single patient with treatment failure than in the remaining three patients with treatment success. No other PET parameters at baseline or follow-up were associated with the treatment results. Conclusions: Pretreatment volume-based ¹⁸F-FDG PET/CT lung parameters were associated with the final therapeutic response in patients with pulmonary MDR-TB. Our preliminary results warrant a larger study.

Immunonutritional status and pulmonary cavitation in patients with tuberculosis: A revisit with an assessment of neutrophil/lymphocyte ratio

BACKGROUND

Several reports have described the importance of immunological and nutritional factors in the morbidity and/or mortality of patients with tuberculosis. The aim of this study was to evaluate the association between pulmonary cavitation and immunonutritional status, assessed by parameters such as neutrophil/lymphocyte ratio (NLR) and prognostic nutritional index (PNI), in patients with pulmonary tuberculosis.

METHODS

We retrospectively analyzed the data of 137 patients with culture-positive active pulmonary tuberculosis without bacterial pneumonia diagnosed at Kainan Hospital between April 2008 and March 2016. The associations between the levels of serum albumin, lymphocytes, NLR, PNI, platelet to lymphocyte ratio (PLR), and body mass index (BMI) and pulmonary cavitation were evaluated in the patients.

RESULTS

A total of 83 men and 63 women (median age, 75 years; range, 16-94 years) were included in the study. Sixty-six patients had smoking history; 55 patients had respiratory symptoms, while 44 patients did not have any symptoms. Patient׳s delay, defined as medical examination performed over 60 days after the onset of symptoms was observed in 25 patients. Univariate analysis showed that high NLR (≥ 5), high PLR (≥200), low serum albumin (<3 g/dL), high neutrophil count (≥6000/mm³), and low lymphocyte count (<1000/mm³) were associated with pulmonary cavitation. Multivariate analysis showed that high NLR and low serum albumin were associated with pulmonary cavitation.

CONCLUSION

Malnutrition and increased severity of inflammation may be associated with pulmonary cavitation in patients with tuberculosis. Further studies are warranted to confirm the findings of the present study.

Recent advances for identification of new scaffolds and drug targets for Mycobacterium tuberculosis

Tuberculosis (TB) is a leading cause of mortality and morbidity with an estimated 1.7 billion people latently infected with the pathogen worldwide. Clinically, TB infection presents itself as an asymptomatic infection, which gradually manifests to life threatening disease. The emergence of various drug resistant strains of Mycobacterium tuberculosis and lengthy duration of chemotherapy are major challenges in the field of TB drug development. Hence, there is an urgent need to develop scaffolds that possess a novel mechanism of action, can shorten the duration of therapy, and are active against both drug resistant and susceptible strains. In this review, we will discuss recent progress made in the field of TB drug development with emphasis on screening methods and drug targets from M. tuberculosis. The current review provides insights into mechanism of action of new scaffolds that are being evaluated in various stages of clinical trials. © 2018 IUBMB Life, 70(9):905-916, 2018.

[Clinical and microbiological profile of patients experiencing relapses of tuberculosis in Tunisia]

INTRODUCTION

Relapse of tuberculosis (TB) is known to be as one of the major risk factors for resistant TB. The aim of this study is to focus on clinical, radiological and bacteriological features of patients with pulmonary TB relapse.

METHODS

We performed a retrospective survey in the respiratory department of the teaching hospital La Rabta in Tunis between January 2000 and December 2014. Data of patients with a pulmonary TB relapse were analyzed.

RESULTS

During the study period, among 1250 patients hospitalized for pulmonary TB, 44 had a TB relapse. The TB relapse rate was estimated to be at 3.5%. The average age was 43.95±16.7 years. Sex ratio was 5,2. Eighty one percent of patients were current smokers. Alcoholism was found in 40.9% of cases. The mean time to relapse was 6.37±3.7 years. The radiological lesions were moderately extended at least in 54.6% of cases. A resistant TB was found in 33% of cases (mono-resistance: 33.3%, multi-drug resistance (TB-MR): 11,1%, poly-resistance: 55.5%). The most incriminated drugs were isoniazid, rifampicin and pyrazinamide. One patient received TB-MR treatment regimen for 18 months. In the other cases, the duration of treatment was prolonged. Recovery was obtained in 72.7% of cases, two patients died and 22.7% of patients were lost to follow up.

CONCLUSION

In Tunisia, TB relapse usually affects young male patients who are often alcoholic and smokers. Resistant TB is frequent among these patients. These findings lead us to emphasize the need of rapid diagnosis tools and adapted treatment regimen in these patients.

Impact of Cigarette Smoking on the Gastrointestinal Tract Inflammation: Opposing Effects in Crohn's Disease and Ulcerative Colitis

Cigarette smoking is a major risk factor for gastrointestinal disorders, such as peptic ulcer, Crohn’s disease (CD), and several cancers. The mechanisms proposed to explain the role of smoking in these disorders include mucosal damage, changes in gut irrigation, and impaired mucosal immune response. Paradoxically, cigarette smoking is a protective factor for the development and progression of ulcerative colitis (UC). UC and CD represent the two most important conditions of inflammatory bowel diseases, and share several clinical features. The opposite effects of smoking on these two conditions have been a topic of great interest in the last 30 years, and has not yet been clarified. In this review, we summarize the most important and well-understood effects of smoking in the gastrointestinal tract; and particularly, in intestinal inflammation, discussing available studies that have addressed the causes that would explain the opposite effects of smoking in CD and UC.

Risk factors for infectiousness of patients with tuberculosis: a systematic review and meta-analysis

We performed a systematic review and meta-analyses of studies assessing tuberculosis (TB) patient-related risk factors for transmission of Mycobacterium tuberculosis infection. Meta-analyses were conducted for sputum smear-positivity, lung cavitation and HIV seropositivity of index patients with both crude and adjusted odds ratios (AORs) pooled using random effect models. Thirty-seven studies were included in the review. We found that demographic characteristics such as age and sex were not significant risk factors, while behaviours such as smoking and alcohol intake were associated with infectiousness although inconsistently. Treatment delay of >28 days was a significant predictor of greater infectiousness. Contacts of sputum smear-positive index patients were found to be more likely to be infected than contacts of sputum smear-negative patients, with a pooled AOR of 2.15 (95% confidence interval (CI) 1.47-3.17, I 2 = 38%). Similarly, contacts of patients with the cavitary disease were around twice as likely to be infected as contacts of patients without cavitation (pooled AOR 1.9, 95% CI 1.26-2.84, I 2 = 63%). In contrast, HIV seropositive patients were associated with few contact infections than HIV seronegative patients (AOR 0.45, 95% CI 0.26-0.80, I 2 = 52%). In conclusion, behavioural and clinical characteristics of TB patients can be used to identify highly infectious patients for targeted interventions.

Mycobacterium tuberculosis Infection in Close Childhood Contacts of Adults with Pulmonary Tuberculosis is Increased by Secondhand Exposure to Tobacco

Tobacco use is a major risk factor for tuberculosis (TB). Secondhand smoke (SHS) is also a risk factor for TB and to a lesser extent, Mycobacterium tuberculosis infection without disease. We investigated the added risk of M. tuberculosis infection due to SHS exposure in childhood contacts of TB cases in The Gambia. Participants were childhood household contacts aged ≤ 14 years of newly diagnosed pulmonary TB (PTB) cases. The intensity of exposure to the case was categorized according to whether contacts slept in the same room, same house, or a different house as the case. Contacts were tested with an enzyme-linked immunospot interferon gamma release assay. In multivariate regression models, M. tuberculosis infection was associated with increasing exposure to a case (odds ratios [OR]: 3.9, 95% confidence interval [CI]: 2.11-71.4, P < 0.001]) and with male gender (OR: 1.5 [95% CI: 1.12-2.11], P = 0.008). Tobacco use caused a 3-fold increase in the odds of M. tuberculosis infection in children who slept closest to a case who smoked within the same home compared with a nonsmoking case (OR: 8.0 [95% CI: 2.74-23.29] versus 2.4 [95% CI: 1.17-4.92], P < 0.001). SHS exposure as an effect modifier appears to greatly increase the risk of M. tuberculosis infection in children exposed to PTB cases. Smoking cessation campaigns may be important for reducing transmission of M. tuberculosis to children within households.

Integrating Lung Physiology, Immunology, and Tuberculosis

Lungs are directly exposed to the air, have enormous surface area, and enable gas exchange in air-breathing animals. They are constantly 'attacked' by microbes from both outside and inside and thus possess a unique, highly regulated local immune defense system which efficiently allows for microbial clearance while minimizing damaging inflammatory responses. As a prototypic host-adapted airborne pathogen, Mycobacterium tuberculosis traverses the lung and has several 'interaction points' (IPs) which it must overcome to cause infection. These interactions are critical, not only from a pathogenesis perspective but also in considering the effectiveness of therapies and vaccines in the lungs. Here we discuss emerging views on immunologic interactions occurring in the lungs for M. tuberculosis and their impact on infection and persistence.

Clinico-Radiologic and Spirometric Profile of an Indian Population with Post-Tuberculous Obstructive Airway Disease

INTRODUCTION

Tuberculosis is a public health problem in developing countries and in spite of receiving adequate anti-tuberculous therapy, patients often continues to have several post-tuberculous sequelae, especially airflow limitation.

AIM

To evaluate pulmonary function by spirometry among post-tuberculosis cases with airway obstruction and their relationship with smoking.

MATERIALS AND METHODS

All patients who presented to the pulmonary medicine Outpatient Department (OPD) with symptoms of obstructive airway disease and had completed adequate anti-tuberculous therapy for pulmonary tuberculosis were taken up for study. They were initially evaluated with sputum smear for Acid Fast Bacilli (AFB) and chest X-ray. Patients without evidence of active tuberculosis underwent spirometry and those having post-bronchodilator Forced Expiratory Volume in first second (FEV1)/ Forced Vital Capacity (FVC) FEV1/FVC<0.7 were taken up for final analysis. Spirometric parameters were compared between smokers and non-smokers.

RESULTS

Out of 138 finally selected cases, 84.06% were male and 71.01% were within age range of 40-69 years. Significant positive association was found between extent of radiologic lesion and severity of airflow obstruction. Purely obstructive pattern was found in 27.54% cases and 72.46% showed mixed pattern. Patients with mixed ventilatory abnormality had worse pulmonary function and poorer bronchodilator reversibility than patients with pure obstruction. Comparison of post-bronchodilator FEV1, FVC, Peak Expiratory Flow (PEF) and Forced Expiratory Flow (FEF) 25-75 between smokers and non-smokers did not show statistically significant difference.

CONCLUSION

Majority of patients with post-tuberculous obstructive airway disease have associated restrictive component. But smoking did not cause significant alteration in pulmonary function among such patients.

Tuberculosis in migrants moving from high-incidence to low-incidence countries: a population-based cohort study of 519 955 migrants screened before entry to England, Wales, and Northern Ireland

BACKGROUND

Tuberculosis elimination in countries with a low incidence of the disease necessitates multiple interventions, including innovations in migrant screening. We examined a cohort of migrants screened for tuberculosis before entry to England, Wales, and Northern Ireland and tracked the development of disease in this group after arrival.

METHODS

As part of a pilot pre-entry screening programme for tuberculosis in 15 countries with a high incidence of the disease, the International Organization for Migration screened all applicants for UK visas aged 11 years or older who intended to stay for more than 6 months. Applicants underwent a chest radiograph, and any with results suggestive of tuberculosis underwent sputum testing and culture testing (when available). We tracked the development of tuberculosis in those who tested negative for the disease and subsequently migrated to England, Wales, and Northern Ireland with the Enhanced Tuberculosis Surveillance system. Primary outcomes were cases of all forms of tuberculosis (including clinically diagnosed cases), and bacteriologically confirmed pulmonary tuberculosis.

FINDINGS

Our study cohort was 519 955 migrants who were screened for tuberculosis before entry to the UK between Jan 1, 2006, and Dec 31, 2012. Cases notified on the Enhanced Tuberculosis Surveillance system between Jan 1, 2006, and Dec 31, 2013, were included. 1873 incident cases of all forms of tuberculosis were identified, and, on the basis of data for England, Wales, and Northern Ireland, the estimated incidence of all forms of tuberculosis in migrants screened before entry was 147 per 100 000 person-years (95% CI 140-154). The estimated incidence of bacteriologically confirmed pulmonary tuberculosis in migrants screened before entry was 49 per 100 000 person-years (95% CI 45-53). Migrants whose chest radiographs were compatible with active tuberculosis but with negative pre-entry microbiological results were at increased risk of tuberculosis compared with those with no radiographic abnormalities (incidence rate ratio 3·2, 95% CI 2·8-3·7; p<0·0001). Incidence of tuberculosis after migration increased significantly with increasing WHO-estimated prevalence of tuberculosis in migrants' countries of origin. 35 of 318 983 pre-entry screened migrants included in a secondary analysis with typing data were assumed index cases. Estimates of the rate of assumed reactivation tuberculosis ranged from 46 (95% CI 42-52) to 91 (82-102) per 100 000 population.

INTERPRETATION

Migrants from countries with a high incidence of tuberculosis screened before being granted entry to low-incidence countries pose a negligible risk of onward transmission but are at increased risk of tuberculosis, which could potentially be prevented through identification and treatment of latent infection in close collaboration with a pre-entry screening programme.

FUNDING

Wellcome Trust, UK National Institute for Health Research, UK Medical Research Council, Public Health England, and Department of Health Policy Research Programme.

On the association between outdoor PM2.5 concentration and the seasonality of tuberculosis for Beijing and Hong Kong

Tuberculosis (TB) is still a serious public health problem in various countries. One of the long-elusive but critical questions about TB is what the risk factors are and how they contribute for its seasonality. An ecologic study was conducted to examine the association between the variation of outdoor PM_2.5 concentration and the TB seasonality based on the monthly TB notification and PM_2.5 concentration data of Hong Kong and Beijing. Both descriptive analysis and Poisson regression analysis suggested that the outdoor PM_2.5 concentration could be a potential risk factor for the seasonality of TB disease. The significant relationship between the number of TB cases and PM_2.5 concentration was not changed when regression models were adjusted by sunshine duration, a potential confounder. The regression analysis showed that a 10 μg/m³ increase in PM_2.5 concentrations during winter is significantly associated with a 3% (i.e. 18 and 14 cases for Beijing and Hong Kong, respectively) increase in the number of TB cases notified during the coming spring or summer for both Beijing and Hong Kong. Three potential mechanisms were proposed to explain the significant relationship: (1) increased PM_2.5 exposure increases host's susceptibility to TB disease by impairing or modifying the immunology of the human respiratory system; (2) increased indoor activities during high outdoor PM_2.5 episodes leads to an increase in human contact and thus the risk of TB transmission; (3) the seasonal change of PM_2.5 concentration is correlated with the variation of other potential risk factors of TB seasonality. Preliminary evidence from the analysis of this work favors the first mechanism about the PM_2.5 exposure-induced immunity impairment. This work adds new horizons to the explanation of the TB seasonality and improves our understanding of the potential mechanisms affecting TB incidence, which benefits the prevention and control of TB disease.

Smear positive pulmonary tuberculosis and associated factors among homeless individuals in Dessie and Debre Birhan towns, Northeast Ethiopia

BACKGROUND

Tuberculosis (TB) remains one of the globe's deadliest communicable diseases. The homeless individuals are at high risk to acquire TB and multi-drug resistant TB (MDR-TB), because of their poor living conditions and risky behaviors. Tuberculosis and MDR-TB in the homeless individuals can pose a risk to entire communities. However, the magnitude of the problem is not known in Ethiopia. Therefore, the aim of this study was to determine the prevalence and associated factors of smear positive pulmonary TB (PTB) and MDR-TB among homeless individuals in Dessie and Debre Birhan towns, Northeast Ethiopia.

METHODS

A community based cross-sectional study design was conducted from September 2014 to June 2015. Using an active screening with cough of ≥2 weeks, 351 TB suspects homeless individuals were participated in this study. Data were collected by using pre-tested and structured questionnaire. Spot-morning-spot sputum sample was collected and examined for acid-fast bacilli (AFB) using fluorescence microscopy by Auramine O staining technique. All AFB positive sputum was further analyzed by GeneXpert for detection of Mycobacterium tuberculosis complex and rifampicin resistant gene. Univariate and multivariate logistic regressions were applied to identify factors associated with smear positive PTB and P value <0.05 was considered as statistically significant.

RESULTS

The prevalence of smear positive PTB was 2.6 % (95 % CI 1.3-5) among TB suspect homeless individuals. Extrapolation of this study finding implies that there were 505 smear positive PTB per 100,000 homeless individuals. All smear positive PTB sputum specimens were further analyzed by GeneXpert assay, the assay confirmed that all were positive for MTBC but none were resistant to RIF or MDR. Smoking cigarette regularly for greater than 5 years (AOR 10.1, 95 % CI 1.1, 97.7), body mass index lower than 18.5 (AOR 6.9, 95 % CI 1.12, 41.1) and HIV infection (AOR 6.8, 95 % CI 1.1, 40.1) were significantly associated with smear positive PTB.

CONCLUSION

The prevalence of smear positive PTB among TB suspect homeless individuals was 2.6 %. Among smear positive PTB, prevalence of HIV co-infection was very high 5 (55.5 %). Smoking cigarette regularly for greater than 5 years, BMI lower than 18.5 and HIV infection were factors associated with smear positive PTB. Special emphasis is needed for homeless individuals to exert intensive effort to identify undetected TB cases to limit the circulation of the disease into the community.

Modulation of Human Macrophage Responses to Mycobacterium tuberculosis by Silver Nanoparticles of Different Size and Surface Modification

Exposure to silver nanoparticles (AgNP) used in consumer products carries potential health risks including increased susceptibility to infectious pathogens. Systematic assessments of antimicrobial macrophage immune responses in the context of AgNP exposure are important because uptake of AgNP by macrophages may lead to alterations of innate immune cell functions. In this study we examined the effects of exposure to AgNP with different particle sizes (20 and 110 nm diameters) and surface chemistry (citrate or polyvinlypyrrolidone capping) on cellular toxicity and innate immune responses against Mycobacterium tuberculosis (M.tb) by human monocyte-derived macrophages (MDM). Exposures of MDM to AgNP significantly reduced cellular viability, increased IL8 and decreased IL10 mRNA expression. Exposure of M.tb-infected MDM to AgNP suppressed M.tb-induced expression of IL1B, IL10, and TNFA mRNA. Furthermore, M.tb-induced IL-1β, a cytokine critical for host resistance to M.tb, was inhibited by AgNP but not by carbon black particles indicating that the observed immunosuppressive effects of AgNP are particle specific. Suppressive effects of AgNP on the M.tb-induced host immune responses were in part due to AgNP-mediated interferences with the TLR signaling pathways that culminate in the activation of the transcription factor NF-κB. AgNP exposure suppressed M.tb-induced expression of a subset of NF-κB mediated genes (CSF2, CSF3, IFNG, IL1A, IL1B, IL6, IL10, TNFA, NFKB1A). In addition, AgNP exposure increased the expression of HSPA1A mRNA and the corresponding stress-induced Hsp72 protein. Up-regulation of Hsp72 by AgNP can suppress M.tb-induced NF-κB activation and host immune responses. The observed ability of AgNP to modulate infectious pathogen-induced immune responses has important public health implications.

Concomitant presence of culture-proven active pulmonary tuberculosis in patients with chronic obstructive pulmonary disease - A hospital based study

OBJECTIVE

To find out the prevalence of concomitant active pulmonary Tuberculosis (TB) in patients of Chronic Obstructive Pulmonary Disease (COPD) using the gold standard liquid and solid culture media for the detection of acid fast bacillus.

METHODS

Eighty clinically and radiologically diagnosed cases of COPD of any severity, ≥40 years of age with no previous history of anti-tuberculous therapy were selected from department of Pulmonology, Jinnah Hospital, Lahore. Detailed demographic profile, clinical symptomatology and history of smoking were recorded. Sputum samples of these patients were subjected to ZiehlNeelsen (ZN) stain and culture on Lowenstein-Jensen (L.J) medium and Mycobacterium Growth Indicator Tube (MGIT) for the detection and isolation of Mycobacteriumtuberculosis (MTB).

RESULTS

Out of 80 COPD patients, 6 (7.5%) were culture positive for acid fast bacillus consistent with active tuberculous infection. The concomitance was more prevalent in elderly, male, smokers. MGIT was a more sensitive and a rapid technique to detect the presence of mycobacterium as compared to LJ culture media and ZN stain.

CONCLUSION

The prevalence of active TB in COPD patients was 7.5%. Detection was improved when liquid culture media was employed for the detection of acid fast bacillus. Regular monitoring and screening of patients with COPD for PTB should be routinely carried out in susceptible cohort to avoid cross spreading of infection and appropriate management.

The re-emergency and persistence of vaccine preventable diseases

The introduction of vaccination worldwide dramatically reduced the incidence of pathogenic bacterial and viral diseases. Despite the highly successful vaccination strategies, the number of cases among vaccine preventable diseases has increased in the last decade and several of those diseases are still endemic in different countries. Here we discuss some epidemiological aspects and possible arguments that may explain why ancient diseases such as, measles, polio, pertussis, diphtheria and tuberculosis are still with us.

Statement on smoking cessation in COPD and other pulmonary diseases and in smokers with comorbidities who find it difficult to quit

Chronic obstructive pulmonary disease (COPD), lung cancer, asthma and pulmonary tuberculosis are common pulmonary diseases that are caused or worsened by tobacco smoking. Growing observational evidence suggests that symptoms and prognosis of these conditions improve upon smoking cessation. Despite increasing numbers of (small) randomised controlled trials suggesting intensive smoking cessation treatments work in people with pulmonary diseases many patients are not given specific advice on the benefits or referred for intensive cessation treatments and, therefore, continue smoking.This is a qualitative review regarding smoking cessation in patients with COPD and other pulmonary disorders, written by a group of European Respiratory Society experts. We describe the epidemiological links between smoking and pulmonary disorders, the evidence for benefits of stopping smoking, how best to assess tobacco dependence and what interventions currently work best to help pulmonary patients quit. Finally, we describe characteristics and management of any "hardcore" smoker who finds it difficult to quit with standard approaches.

Tuberculosis and excess alcohol use in the United States, 1997-2012

BACKGROUND

Excess alcohol use among tuberculosis (TB) patients complicates TB control strategies.

OBJECTIVES

To characterize the role of excess alcohol use in TB control, we describe the epidemiology of excess alcohol use and TB in the United States among those aged ⩾15 years.

DESIGN

Using data reported to the National Tuberculosis Surveillance System, 1997-2012, we examined associations between excess alcohol use and TB treatment outcomes and markers for increased transmission (involvement in a local genotype cluster of cases) using multivariate logistic regression. We used Cox proportional hazards regression analysis to examine the relationship between excess alcohol use and the rate of conversion from positive to negative in sputum culture results.

RESULTS

Excess alcohol use was documented for 31 207 (15.1%) of 207 307 patients. Prevalence of excess alcohol use was greater among male patients (20.6%) and US-born patients (24.6%). Excess alcohol use was associated with a positive sputum smear result (aOR 1.23, 95%CI 1.18-1.28) and death during treatment (vs. completion of treatment) (aOR 1.16, 95%CI 1.10-1.22). The rate of culture conversion was higher among patients without excess alcohol use (adjusted hazard ratio 1.20, 95%CI 1.18-1.23).

CONCLUSIONS

Excess alcohol use was common among patients with TB, and was associated with TB transmission, lower rates of sputum culture conversion, and greater mortality.

Risk factors for tuberculosis in older children and adolescents: a matched case-control study in Recife, Brazil

Background

Tuberculosis is a major disease worldwide and most research focus on risk factors for adults, although there is a marked adolescent peak in incidence. The objective of this study was to identify risk factors for tuberculosis in children aged 7 to 19.

Methods

A case control study matched by age with 169 cases and 477 controls. The study population consisted of adolescents and older children from Recife, Brazil. Cases were individuals diagnosed with tuberculosis in the control programme and controls were selected in the neighborhood of cases. Conditional logistic regression was used to identify risk factors.

Results

Cigarette smoking increased by 50% the risk of tuberculosis but that this was not statistically significant (OR = 1.6). Other risk factors were sleeping in the same house as a case of tuberculosis (OR = 31.6), living in a house with no piped water (OR = 7.7) (probably as a proxy for bad living conditions), illiteracy (OR = 3.7) and male sex (OR = 1.8). The increase in risk with living in houses with no piped water was much more marked in males. The proportion of cases of tuberculosis attributed to contact with someone with TB was 38% and to illiteracy, lack of piped water and smoking, 20%.

Conclusion

Household contact with tuberculosis, social factors and male sex play the biggest role in determining risk of TB disease among children and adolescents in the study. We recommend further research on the relationship of cigarette smoking on tuberculosis in adolescents, and on whether the sex differentials are more marked in bad living conditions. Separate studies should be conducted in older children and in adolescents.

[Pulmonary tuberculosis and tobacco: about 100 cases]

Le tabagisme et la tuberculose sont deux enjeux majeurs de santé publique au niveau mondial, en particulier dans les pays émergents. Pour déterminer les particularités cliniques, radiologiques, bactériologiques et thérapeutiques de la tuberculose pulmonaire chez les sujets tabagiques nous avons mené une étude prospective au service de phtisiologie de l'hôpital Moulay Youssef sur une période de 10 mois, portant sur 100 nouveaux cas de tuberculose pulmonaire, répartis en 2 groupes, 50 patients tabagiques: Groupe A et 50 patients non tabagiques: Groupe B. Tous nos patients étaient de sexe masculin, l’âge moyen était de 41 ans ± 12 chez le groupe A et de 36 ans ± 16 chez le groupe B. Le délai de consultation était plus long chez les tabagiques, la médiane était de 60j (30; 98) contre 40j (30; 60), la symptomatologie clinique était variable chez les deux groupes, dominée par les expectorations chez les tabagiques 96% contre 60%. Les lésions radiologiques étaient similaires chez les deux groupes ainsi que la charge bacillaire. Tous les patients ont été mis sous traitement antituberculeux. Après un mois du traitement, la Bacilloscopie était négative chez 50% du groupe A contre 66% chez le groupe B. la régression des lésions radiologiques était similaire chez les deux groupes. Le retard diagnostique et le retard de négativation des frottis sont les principales particularités de la tuberculose pulmonaire du sujet tabagique. Le sevrage tabagique doit faire partie intégrante de la prise en charge des patients atteints de tuberculose.

Impact of passive smoking, cooking with solid fuel exposure, and MBL/MASP-2 gene polymorphism upon susceptibility to tuberculosis

BACKGROUND

To explore the impact of passive smoking, cooking with solid fuel, mannose-binding lectin (MBL) gene, MBL-associated serine proteases 2 (MASP-2) gene, and gene-environment interactions on the susceptibility to tuberculosis (TB) in non-smokers.

METHODS

A total of 205 TB patients and 216 healthy controls were recruited to participate in this case-control study. PCR with sequence-specific primers (PCR-SSP) technology was leveraged to genotype rs7096206 of MBL genes and rs2273346 and rs6695096 of MASP-2 genes. Demographic data and information on exposures of participants were collected. Unconditioned logistic regression analysis was conducted to identify associations between the various factors and TB, and marginal structural linear odds models were used to estimate the interactions.

RESULTS

Passive smoking and cooking with solid fuel were associated with the risk of TB, with odds ratios (OR) of 1.58 and 2.93, respectively (p<0.05). Genotype CG at rs7096206 of MBL genes (OR 2.02) and genotype TC at rs6695096 of MASP-2 genes (OR 1.67) were more prevalent in the TB patients than in healthy controls (p<0.05). The relative excess risk of interaction (RERI) between rs7096206 of MBL genes and passive smoking or cooking with solid fuel exposure was 1.86 (95% confidence interval (CI) 0.59-3.16) and 2.66 (95% CI 1.85-3.47), respectively. The RERI between rs6695096 of MASP-2 genes and cooking with solid fuel exposure was 3.70 (95% CI 2.63-4.78), which was also a positive interaction. However, the RERI between rs6695096 of MASP-2 genes and passive smoking was not statistically significant.

CONCLUSIONS

Passive smoking, cooking with solid fuel, and polymorphisms of MBL (rs7096206) and MASP-2 (rs6695096) genes were associated with susceptibility to TB in non-smokers, and there were gene-environment interactions among them. Further studies are needed to explore details of the mechanisms of association.

Smear positive pulmonary tuberculosis and its risk factors among tuberculosis suspect in South East Ethiopia; a hospital based cross-sectional study

BACKGROUND

Tuberculosis remains a deadly infectious disease, affecting millions of people worldwide. Ethiopia ranks seventh among the twenty two high tuberculosis burden countries. The aim of this study was to determine the prevalence of smear positive pulmonary tuberculosis and its associated risk factors in Goba and Robe hospitals of Bale zone.

METHODS

A cross-sectional study was conducted on tuberculosis suspected patients from February-May 2012. Sputum samples were examined for acid fast bacilli using Ziehl-Neelsen staining and interview was conducted for each patient. Descriptive statistics, binary logistic and multivariable logistic regression analyses were employed to identify factors associated with pulmonary tuberculosis infection.

RESULT

The prevalence of smear positive tuberculosis was 9.2%. Age >36 (AOR = 3.54, 95% CI = 1. 3-9.82), marital status (AOR = 8.40, 95% CI = 3.02-23.20), family size (AOR = 4. 10, 95% CI = 1.60-10.80), contact with active tuberculosis patient (AOR = 5. 90; 95% CI = 2. 30-15.30), smoking cigarette regularly (AOR = 3. 90; 95% CI = 1. 20-12.40), and human immunodeficiency virus sero-status (AOR = 11. 70; 95% CI = 4. 30-31.70) were significantly associated with smear positive pulmonary tuberculosis.

CONCLUSION

The prevalence of smear positive pulmonary tuberculosis was high in the study area. Age, marital status, family size, history of contact with active tuberculosis patient, smoking cigarettes, and HIV sero-status were among the risk factors significantly associated with acquiring tuberculosis. Hence, strict pulmonary tuberculosis screening of HIV patients and intensification of health education to avoid risk factors identified are recommended.

Cigarette smoke impairs cytokine responses and BCG containment in alveolar macrophages

BACKGROUND

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

METHODOLOGY

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

RESULTS

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

CONCLUSIONS

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

An overview of the risk factors associated with multiple oral premalignant lesions with a case report of extensive field cancerization in a female patient

BACKGROUND

Field cancerization is a well-known and well-documented process of malignant transformation first coined by Slaughter et al. in 1953. Tobacco chewing was associated with the greatest increase in the risk of multiple oral premalignant lesions and may be the major source of field cancerization of the oral cavity in the Indian population. The field cancerization will probably help clinicians in complementing evaluation of pathologic biopsy specimens.

MATERIAL AND METHODS

We present a case report of field cancerization in a 63-year-old Indian female. She presented with an intra-oral generalized hyperkeratotic verruciform type white lesions involving right and left buccal mucosa, lower labial mucosa, upper and lower vestibule, dorsal, ventral and right lateral border of the tongue, hard and soft palate. Microscopic examination revealed features of verrucous carcinoma in one area, squamous cell carcinoma in another and carcinoma in situ in other areas. Based on the overall features in various areas of the oral cavity, the lesion was diagnosed as field cancerization.

CONCLUSION

Reviewing the literature revealed the presence of a field with genetically altered cells appear to be induced by tobacco (smoking/smokeless form). The large number of premalignant cells in the fields may increase cancer risk considerably. Thus screening and monitoring of the field may have serious implications for oral cancer prevention.

Smoking and 2-month culture conversion during anti-tuberculosis treatment

OBJECTIVE

To investigate risk factors for delayed sputum culture conversion to negative during anti-tuberculosis treatment, with an emphasis on smoking.

DESIGN

Nested case-control study of adults with non-cavitary, culture-confirmed pulmonary tuberculosis (TB) participating in an anti-tuberculosis treatment trial in Brazil. A case of delayed culture conversion was a patient who remained culture-positive after 2 months of treatment. Odds ratios with 95% confidence intervals were calculated.

RESULTS

Fifty-three cases and 240 control patients were analyzed. Smokers had three-fold greater odds of remaining culture-positive after 2 months of treatment (P = 0.007) than non-smokers, while smokers and ex-smokers who smoked >20 cigarettes a day had two-fold greater odds of remaining culture-positive after 2 months of treatment (P = 0.045).

CONCLUSION

Cigarette smoking adversely affects culture conversion during anti-tuberculosis treatment. Support for smoking cessation should be considered to improve outcomes in TB control programs.

Allopatric tuberculosis host-pathogen relationships are associated with greater pulmonary impairment

BACKGROUND

Host pathogen relationships can be classified as allopatric, when the pathogens originated from separate, non-overlapping geographic areas from the host; or sympatric, when host and pathogen shared a common ancestral geographic location. It remains unclear if host-pathogen relationships, as defined by phylogenetic lineage, influence clinical outcome. We sought to examine the association between allopatric and sympatric phylogenetic Mycobacterium tuberculosis lineages and pulmonary impairment after tuberculosis (PIAT).

METHODS

Pulmonary function tests were performed on patients 16 years of age and older who had received ≥20 weeks of treatment for culture-confirmed M. tuberculosis complex. Forced Expiratory Volume in 1 min (FEV1) ≥80%, Forced Vital Capacity (FVC) ≥80% and FEV1/FVC >70% of predicted were considered normal. Other results defined pulmonary impairment. Spoligotype and 12-locus mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) were used to assign phylogenetic lineage. PIAT severity was compared between host-pathogen relationships which were defined by geography and ethnic population. We used multivariate logistic regression modeling to calculate adjusted odds ratios (aOR) between phylogenetic lineage and PIAT.

RESULTS

Self-reported continental ancestry was correlated with Mycobacterium. tuberculosis lineage (p<0.001). In multivariate analyses adjusting for phylogenetic lineage, age and smoking, the overall aOR for subjects with allopatric host-pathogen relationships and PIAT was 1.8 (95% confidence interval [CI]: 1.1, 2.9) compared to sympatric relationships. Smoking >30 pack-years was also associated with PIAT (aOR: 3.2; 95% CI: 1.5, 7.2) relative to smoking <1 pack-years.

CONCLUSIONS

PIAT frequency and severity varies by host-pathogen relationship and heavy cigarette consumption, but not phylogenetic lineage alone. Patients who had disease resulting from allopatric-host-pathogen relationship were more likely to have PIAT than patients with disease from sympatric-host-pathogen relationship infection. Further study of this association may identify ways that treatment and preventive efforts can be tailored to specific lineages and racial/ethnic populations.

Incidence and risk factors for tuberculosis in people living with HIV: cohort from HIV referral health centers in Recife, Brazil

OBJECTIVE

To identify the incidence of and risk factors for tuberculosis in people living with HIV (PLHIV).

DESIGN

Observational, prospective cohort study.

METHODS

A total of 2069 HIV-infected patients was observed between July 2007 and December 2010. The Kaplan-Meier method was used to estimate the probability of survival free of tuberculosis, and Cox regression analysis to identify risk factors associated with the development of tuberculosis.

RESULTS

Survival free of tuberculosis (TB) was 91%. The incidence rate of tuberculosis was 2.8 per 100 persons/years. Incidence of tuberculosis was higher when subjects had CD4 cell count <200 cells/mm(3); were not on antiretroviral therapy; in those who had, a body mass index <18.5 kg/m(2), anemia (or were not tested for it), were illiterate or referred previous tuberculosis treatment at entry into the cohort. Those not treated for latent TB infection had a much higher risk (HR = 7.9) of tuberculosis than those with a negative tuberculin skin test (TST). Having a TST≥5 mm but not being treated for latent TB infection increased the risk of incident tuberculosis even in those with a history of previous tuberculosis.

CONCLUSIONS

Preventive actions to reduce the risk of TB in people living with HIV should include an appropriate HAART and treatment for latent TB infection in those with TST≥5 mm. The actions towards enabling rigorous implementation of treatment of latent TB infection and targeting of PLHIV drug users both at the individual and in public health level can reduce substantially the incidence of TB in PLHIV.

Smear positive pulmonary tuberculosis among diabetic patients at the Dessie referral hospital, Northeast Ethiopia

Background

Tuberculosis (TB) is an infectious disease which is still a major cause of morbidity and mortality throughout the world. People with diabetes mellitus (DM) have a three times higher risk of developing active TB than people without diabetes. However, there is not enough credible information on the burden of pulmonary tuberculosis (PTB) among DM patients in Ethiopia, in general, and in the city of Dessie, in particular. Therefore, this study aims to determine the prevalence and associated risk factors of smear positive PTB among diabetic patients at a referral hospital in Dessie.

Methods

A cross-sectional study was conducted from February 2012 to April 2012. Patient demographic characteristics were collected using a pre-tested standard questionnaire format. Spot-morning-spot sputum specimens were collected from the study participants and examined for acid-fast bacilli using direct microscopy by the Ziehl-Neelsen staining technique. Data was entered and analyzed using the SPSS version 16 statistical software and p-value <0.05 was considered as statistically significant.

Results

Out of 225 TB suspected diabetic patients, 52% were males and 48% were females. Their ages ranged from 12 to 82 years, with a mean age of 47.2 years. Urban residence (AOR: 5.5; 95% CI: 1.07–28.20), history of TB (AOR: 13.4; 95% CI: 2.74–65.73), contact with TB patients in the family (AOR: 9.4; 95% CI: 1.822–48.50), and long duration of DM (AOR: 8.89; 95% CI: 1.88–58.12) were independently associated with the development of active TB in people living with DM.

Conclusions

The prevalence of smear positive PTB was 6.2% in TB suspected diabetic patients, which is higher compared with the general population (0.39%). Patients with a previous history of contact with TB patients, as well as those who had prolonged diabetes, were more prone to have PTB. Therefore, screening of diabetic patients for PTB infection during follow-up is necessary.