Tuberculosis: epidemiology and control

Watching DNA Replication Inhibitors in Action: Exploiting Time-Lapse Microfluidic Microscopy as a Tool for Target-Drug Interaction Studies in Mycobacterium

Spreading resistance to antibiotics and the emergence of multidrug-resistant strains have become frequent in many bacterial species, including mycobacteria, which are the causative agents of severe diseases and which have profound impacts on global health. Here, we used a system of microfluidics, fluorescence microscopy, and target-tagged fluorescent reporter strains of Mycobacterium smegmatis to perform real-time monitoring of replisome and chromosome dynamics following the addition of replication-altering drugs (novobiocin, nalidixic acid, and griselimycin) at the single-cell level. We found that novobiocin stalled replication forks and caused relaxation of the nucleoid and that nalidixic acid triggered rapid replisome collapse and compaction of the nucleoid, while griselimycin caused replisome instability, with the subsequent overinitiation of chromosome replication and overrelaxation of the nucleoid. In addition to study target-drug interactions, our system also enabled us to observe how the tested antibiotics affected the physiology of mycobacterial cells (i.e., growth, chromosome segregation, etc.).

Prevalence of pulmonary tuberculosis among students in three eastern Ethiopian universities

SETTINGS

Three universities located in eastern Ethiopia: Haramaya University, Haramaya; Dire-Dawa University, Dire-Dawa; and Jigjiga University, Jigjiga.

OBJECTIVE

To determine the burden of pulmonary tuberculosis (PTB) among university students and to identify risk factors for the development of TB disease.

DESIGN

All full-time university students were screened for symptoms of PTB and sputum was collected for acid-fast bacilli (AFB) examination and culture for Mycobacterium tuberculosis.

RESULTS

Of 35 344 students screened, we identified 153 PTB cases that occurred over the 1-year study period, or 433/100 000 students. Of these, 117 (76%) PTB cases were found through passive case finding at student health centres, while 36 (24%) previously undiagnosed patients were identified through active case finding. Sixteen cases detected using active case finding (44%) were smear-positive. Living in a dormitory with 5 students and attending university for 2 years were both significantly associated with PTB (adjusted OR 2.49 and 3.79, respectively, P < 0.001). In persons who underwent drug susceptibility testing, 11 (30.5%) had resistance to at least one first-line anti-tuberculosis drug.

CONCLUSION

We found a high burden of TB among university students in eastern Ethiopia. Screening for PTB upon university admission and at regular intervals should be considered to minimise TB transmission on university campuses.

Epidemiology and disease burden of tuberculosis in south of Tunisia over a 22-year period: Current trends and future projections

BACKGROUND

Tuberculosis (TB) is a public health problem worldwide. Characterizing its trends over time is a useful tool for decision-makers to assess the efficiency of TB control programs. We aimed to give an update on the current chronological trends of TB in Southern Tunisia from 1995 to 2016 and to estimate future trajectories of TB epidemic by 2030.

METHODS

We retrospectively collected data of all notified TB new cases by the Center of Tuberculosis Control between 1995 and 2016 in South of Tunisia. Joinpoint Regression Analysis was performed to analyze chronological trends and annual percentage changes (APC) were estimated.

RESULTS

In the past 22 years, a total of 2771 cases of TB were notified in Southern Tunisia. The annual incidence rate of TB was 13.91/100,000 population/year. There was a rise in all forms of TB incidence (APC = 1.63) and in extrapulmonary tuberculosis (EPTB) (APC = 2.04). The incidence of TB increased in children and adult females between 1995 and 2016 (APC = 4.48 and 2.37, respectively). The annual number of TB declined in urban districts between 2004 and 2016 (APC = -2.85). Lymph node TB cases increased (APC = 4.58), while annual number of urogenital TB decreased between 1995 and 2016 (APC = -3.38). Projected incidence rates would increase to 18.13 and 11.8/100,000 population in 2030 for global TB and EPTB, respectively.

CONCLUSIONS

Our study highlighted a rise in all forms of TB and among high-risk groups, notably children, females and lymph node TB patients in the last two decades and up to the next one.

Plasma levels of C-reactive protein, matrix metalloproteinase-7 and lipopolysaccharide-binding protein distinguish active pulmonary or extrapulmonary tuberculosis from uninfected controls in children

The immune profile associated with distinct clinical forms of tuberculosis (TB) has been extensively described for adult populations. Nevertheless, studies describing immune determinants of pulmonary or extrapulmonary TB (PTB or EPTB, respectively) in children are scarce. Here, we retrospectively assessed plasma levels of several mediators of inflammation in age and sex-matched children from South India presenting with PTB (n = 14) or EPTB (n = 22) as well as uninfected healthy controls (n = 19) to identify biomarkers that could accurately distinguish different TB clinical forms. Furthermore, we performed exploratory analyses testing the influence of sex on the systemic inflammatory profile. The analyses identified a biosignature of 10 biomarkers capable of distinguishing the three clinical groups simultaneously. Machine-learning decision trees indicated that C-reactive protein (CRP), matrix metalloproteinase (MMP)-7 and lipopolysaccharide-binding protein (LBP) were the markers that, when combined, displayed the highest accuracy in identifying the clinical groups. Additional exploratory analyses suggested that the disease signatures were highly influenced by sex. Therefore, sex differentially impacted status of systemic inflammation, immune activation and tissue remodeling in children with distinct clinical forms of TB. Regardless of such nuances related to biological sex, MMP-7, CRP and LBP were strong discriminators of active TB and thus could be considered as biomarkers useful in discrimination different TB clinical forms. These observations have implications on our understanding of the immunopathology of both clinical forms of TB in pediatric patients. If validated by other studies in the future, the combination of identified biomarkers may help development of point-of-care diagnostic or prognostic tools.

Blastocystis subtype 1 (allele 4); Predominant subtype among tuberculosis patients in Iran

BACKGROUND

Blastocystis and tuberculosis are two public health issues that are frequently reported in regions with low level of hygiene. Therefore, the current study aimed to investigate Blastocystis subtype and allele distribution in TB patients.

METHODS

Totally, 161 stool samples were taken from TB patients who were undergoing anti-MTB treatment. Stool samples were concentrated using conventional formalin-ether technique and examined using Lugol's iodine staining under light microscopy. DNA extraction was carried out and discriminative fragment was amplified and sequenced. With comparison in GenBank database, relevant subtypes and alleles were characterized and phylogenetically analyzed using MEGA v.7 and Tamura 3-parameter model.

RESULTS

In total, from 161 stool samples, 19 samples were suspected to be Blastocystis-positive. The expected fragment was amplified in 13 (8.07%) of samples. Accordingly, 11/13 (84.62%) of Blastocystis cases settled in urban and 2/13 (15.38%) were villagers. Close-contact with animals was also seen among 7/13 (53.84%) of samples. Subtype 1 (7/13; 53.84%) was the most prevalent followed by subtype 2 (5/13; 38.46%) and subtype 3 (1/13, 7.69%). All ST1 were allele 4, while alleles 9, 11 and 12 were seen in ST2 and allele 34 was the only allele observed in ST3. All three subtypes were clearly separated, while there was no separation between sequences from TB and non-TB patients.

CONCLUSION

Blastocystis ST1 was the most prevalent subtype in TB patients and there was no difference between Blastocystis isolates from TB and non-TB human subjects.

The protective effect of isoniazid preventive therapy on tuberculosis incidence among HIV positive patients receiving ART in Ethiopian settings: a meta-analysis

Background

Tuberculosis (TB) and HIV makeup a deadly synergy of infectious disease, and the combined effect is apparent in resource limited countries like Ethiopia. Previous studies have demonstrated inconsistent results about the protective effect of isoniazid preventive therapy (IPT) on active TB incidence among HIV positive patients receiving ART. Therefore, the aim of this meta-analysis was, first, to determine the protective effect of IPT on active tuberculosis incidence, and second, to assess the pooled incidence of active TB among HIV positive patients taking ART with and without IPT intervention in Ethiopia.

Methods

PubMed, Google scholar and Cochran library databases were searched from April 1 to 30, 2018. Two independent authors explored and assessed studies for eligibility, and extracted data based on predefined criteria. Studies that reported TB incidence among HIV positive patients taking ART in Ethiopia with and without IPT concomitant intervention, and with a clear stratified data on the incidence of TB based on the duration of IPT intervention were selected. A random effects model was used to estimate risk ratios and the pooled incident TB with the respective 95% confidence intervals.

Results

We identified 7 suitable studies in this analysis. Accordingly, IPT reduced the risk of TB incidence by 74%, risk ratio (RR) 0.26 (95% CI; 0.16–0.43%), compared to no IPT group. Moreover, IPT for 12 months reduced incident TB by 91% (RR: 0.09, 95% CI: 0.04 to 0.21), whereas 6 months IPT averted TB incidence by 63% (RR: 0.37, 95% CI: 0.26 to 0.52). The overall pooled incident TB among HIV infected patients receiving ART was 10.30% (95% CI; 7.57–13.02%). Specifically, incident TB among study cohorts with and without IPT was 3.79% (95% CI; 2.03–5.55%) and 16.32% (95% CI; 11.57–21.06%) respectively.

Conclusion

IPT reduced the risk of incident TB among HIV positive patients receiving ART in Ethiopian settings. Moreover, the duration of IPT intervention has effect on its protective role. Thus, scaling up the isoniazid preventive therapy program and its strict compliance is necessary to avert HIV fueled tuberculosis.

Study protocol registration

CRD42018090804.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4031-2) contains supplementary material, which is available to authorized users.

Improving TB case notification in northern Uganda: evidence of a quality improvement-guided active case finding intervention

BACKGROUND

Strategies to identify and treat undiagnosed prevalent cases that have not sought diagnostic services on their own, are necessary to treat TB in patients earlier and interrupt transmission. Late presentation for medical services of symptomatic patients require special efforts to detect early and notify TB in high risk populations. An intervention that combined quality improvement with facility-led active case finding (QI-ACF) was implemented in 10 districts of Northern Uganda with the highest TB burden to improve case notification among populations at highest risk of TB.

METHODS

Using QI-ACF intervention approach in 48 facilities, we; 1) targeted key vulnerable populations, 2) engaged district and facility teams in TB systems strengthening, 3) conducted systematic screening and diagnosis in vulnerable groups (people living with HIV, fishing communities, and prisoners), and 4) trained health workers on national x-ray diagnosis guidelines for smear-negative patients. Facility-led QI-ACF meant that health care providers identified the target population, mobilized and massively screened suspects, and addressed gaps in documentation. Chest X-ray diagnosis was promoted for smear-negative TB among those suspects whose sputum examination was negative. The effect of the intervention on case notification was then assessed separately over the post intervention period.

RESULTS

Over all TB case notification in the intervention districts increased from 171 to 223 per 100,000 population between the baseline months of October-December 2016 and end line month of April-June 2017. TB patient contacts had the majority of TB positive cases identified during active case finding (40, 6.1%). Fishing communities had the highest TB positivity rate at 6.8%. Prisoners accounted for the lowest number of TB positive cases at 34 (2.3%).

CONCLUSION

Targeting should be applied at all levels of TB intervention to improve yield: targeting districts and facilities with the lowest rates of case notification and targeting index patient contacts, HIV clients, and fishing communities. Screening tools are useful to guide health workers to identify presumptive cases. Efforts to improve availability of x-ray for TB diagnosis contributed to almost half of the new cases identified. Having all HIV patients who were eligible for viral load provide sputum for TB screening proved easy to implement.

Migration and health: A retrospective study about the prevalence of HBV, HIV, HCV, tuberculosis and syphilis infections amongst newly arrived migrants screened at the Infectious Diseases Unit of Modena, Italy

INTRODUCTION

Aim of the study is to evaluate the prevalence of HBV, HIV, HCV, tuberculosis and syphilis infection among immigrants assigned to the immigrant centre of the province of Modena.

METHODS

At the time of arrival all immigrant were tested for: HBsAg, HBsAb, HBcAb, Ag p24/HIVAb, HCVAb, RPR, TPPA, Mantoux test (>10mm diameter of induration was considered to be positive), Chest X-rays. In case of positive samples, second level tests were performed (HbeAg, HBeAb, HDVAb, and baseline management and treatment of the infection detected).

RESULTS

A total of 304 immigrant people were enrolled in the study. HBsAg positivity was 12.2%, HCVAb 3.3%, HIVAb 1.6%, TPPA+RPR positivity in the 0.7%; 10.2% had a positive Mantoux test; 5.6% had Chest X-rays positive for signs of infection and 6 patients had an active tuberculosis. 83.8% HBsAg were HBeAb positive/HBeAg negative. HDVAb resulted positive in 1 patient (2.7%). Previous HBV infection was detected in 28.6% of cases, isolated HBcAb in 2.3%; 5.6% of patients resulted to be positive to HbsAb alone (probable vaccinated).

CONCLUSION

Our study confirms the high prevalence of HBsAg positivity and latent tuberculosis among immigrants, underlying the importance of screening for infections in this special population.

Knowledge, beliefs, and perceptions of tuberculosis among community members in Ntcheu district, Malawi

Introduction

The global burden of tuberculosis (TB) remains significantly high, with overreliance on biomedical interventions and inadequate exploration of the socioeconomic and cultural context of the infected population. A desired reduction in disease burden can be enhanced through a broader theoretical understanding of people’s health beliefs and concerns about TB. In this qualitative study, we explore the knowledge, beliefs, and perceptions of community members and people diagnosed with TB toward TB in Ntcheu district, Malawi.

Methods

Using a qualitative phenomenological study design, data were obtained from eight focus-group discussions and 16 individual in-depth interviews. The community’s experiences and perceptions of TB were captured without using any preconceived framework. Adult participants who had had or never had a diagnosis of TB were purposively selected by sex and age and enrolled for the study. Discussions and individual interviews lasting about 60 minutes each were audiotaped, transcribed, and translated into English and analyzed using MaxQDA 10 software for qualitative analysis.

Results

Most participants believed that TB was curable and would go for diagnosis if they had symptoms suggestive of the disease. However, based on their beliefs, individuals expressed some apprehension about the spread of TB and the social implications of being diagnosed with the disease. This perception affected participants’ responses about seeking diagnosis and treatment.

Conclusion

A supportive and collective approach consisting of a combination of mass media, interactive communication campaigns, emphasizing TB symptoms, transmission, and stigma could be useful in addressing barriers to early diagnosis and care-seeking behavior.

Alcohol enhances type 1 interferon-α production and mortality in young mice infected with Mycobacterium tuberculosis

In the current study, we used a mouse model and human blood samples to determine the effects of chronic alcohol consumption on immune responses during Mycobacterium tuberculosis (Mtb) infection. Alcohol increased the mortality of young mice but not old mice with Mtb infection. CD11b+Ly6G+ cells are the major source of IFN-α in the lungs of Mtb-infected alcohol-fed young mice, and IFN-α enhances macrophage necroptosis in the lungs. Treatment with an anti-IFNAR-1 antibody enhanced the survival of Mtb-infected alcohol-fed young mice. In response to Mtb, peripheral blood mononuclear cells (PBMCs) from alcoholic young healthy individuals with latent tuberculosis infection (LTBI) produced significantly higher amounts of IFN-α than those from non-alcoholic young healthy LTBI+ individuals and alcoholic and non-alcoholic old healthy LTBI+ individuals. Our study demonstrates that alcohol enhances IFN-α production by CD11b+Ly6G+ cells in the lungs of young Mtb-infected mice, which leads to macrophage necroptosis and increased mortality. Our findings also suggest that young alcoholic LTBI+ individuals have a higher risk of developing active TB infection.

Chronic alcohol consumption modulates the host immune defense mechanism(s) and makes the host susceptible to various fungal, viral and bacterial infections, including Mycobacterium tuberculosis (Mtb). However, limited information is available about the mechanisms involved in alcohol-mediated host susceptibility to Mtb and other intracellular bacterial infections. In the current study, we fed control and alcohol diets to young and old mice and determined the mortality rates and the immune mechanisms involved in host susceptibility to Mtb infection. We found that alcohol increases the mortality of young mice but not old mice infected with Mtb. The increased mortality in alcohol-fed Mtb-infected young mice was due to IFN-α production by CD11b+Ly6G+ cells. We also found that PBMCs from young alcoholic individuals with latent tuberculosis infection (LTBI) produced significantly higher amounts of IFN-α than those from young non-alcoholic, old alcoholic and old non-alcoholic LTBI+ individuals. Our findings suggest that young alcoholic LTBI+ individuals have a higher risk of developing active TB infection. Our studies provide the first evidence that chronic alcohol consumption induces IFN-α production in young Mtb-infected mice and increases their mortality rates. Further characterization of CD11b+Ly6G+ cells and delineation of the mechanisms through which alcohol enhances IFN-α production in Ly6G+ cells during Mtb infection will facilitate the development of therapies for alcoholic individuals with latent and active Mtb.

In vitro infection with Mycobacterium tuberculosis induces a distinct immunological pattern in blood from healthy relatives of tuberculosis patients

Part of the susceptibility to tuberculosis has a genetic basis, which is clear in primary immunodeficiencies, but is less evident in apparently immunocompetent subjects. Immune responses were analysed in blood samples from tuberculosis patients and their healthy first-degree relatives who were infected in vitro with mycobacteria (either Mycobacterium tuberculosis or M. bovis BCG). The antimicrobial activity against M. tuberculosis in blood from relatives was significantly lower than that observed in healthy controls. Tuberculosis patients exhibited a higher number of neutrophils, and monocyte phagocytosis was inhibited in both relatives and tuberculosis patients. A remarkable finding was that the production of reactive oxygen species by infected neutrophils was higher in relatives than in healthy controls. A higher production of TNFα in infected blood from relatives was also observed. These results may indicate that relatives display a stronger inflammatory response and that their immune response to M. tuberculosis is different from those of unrelated controls. First-degree relatives may represent a highly informative group for the analysis of tuberculosis susceptibility.

Nanoparticles for Signaling in Biodiagnosis and Treatment of Infectious Diseases

Advances in nanoparticle-based systems constitute a promising research area with important implications for the treatment of bacterial infections, especially against multidrug resistant strains and bacterial biofilms. Nanosystems may be useful for the diagnosis and treatment of viral and fungal infections. Commercial diagnostic tests based on nanosystems are currently available. Different methodologies based on nanoparticles (NPs) have been developed to detect specific agents or to distinguish between Gram-positive and Gram-negative microorganisms. Also, biosensors based on nanoparticles have been applied in viral detection to improve available analytical techniques. Several point-of-care (POC) assays have been proposed that can offer results faster, easier and at lower cost than conventional techniques and can even be used in remote regions for viral diagnosis. Nanoparticles functionalized with specific molecules may modulate pharmacokinetic targeting recognition and increase anti-infective efficacy. Quorum sensing is a stimuli-response chemical communication process correlated with population density that bacteria use to regulate biofilm formation. Disabling it is an emerging approach for combating its pathogenicity. Natural or synthetic inhibitors may act as antibiofilm agents and be useful for treating multi-drug resistant bacteria. Nanostructured materials that interfere with signal molecules involved in biofilm growth have been developed for the control of infections associated with biofilm-associated infections.

Patients' perception regarding the influence of individual and social vulnerabilities on the adherence to tuberculosis treatment: a qualitative study

Background

Tuberculosis remains an important disease which mainly affects the majority of vulnerable individuals in society, who are subjected to poor living conditions and difficulties to access the services of public health. Under these circumstances, the present study aims to understand patients’ perception in relation to the influence of individual and social vulnerabilities on the adherence to tuberculosis treatment.

Methods

A qualitative descriptive cross sectional study was conducted in one large municipality at the state of Paraíba, Northeast of Brazil. The study subjects, who were residents of the study site, covered all tuberculosis cases diagnosed between March and June 2015. The sample was defined by the criteria of response saturation. All interviews were audio recorded, and data analysis was developed through the hermeneutic dialectic method and the theory of Generative Route Sense. The project was approved by the Research Ethics Committee of the University of São Paulo (USP).

Results

A total of 13 individuals were interviewed and the responses were identified into two analytical categories: the difficulties they had and the enabling factors they could mention during their tuberculosis treatment. Patients brought up social exclusion as an obstacle to treatment adherence, which, along with stigmatization, weakened their link with family members and health professionals. Moreover, economic precariousness was a major hindrance to the maintenance of a proper diet and transportation access to health centers. However, social support and directly observed treatment helped to break down barriers of prejudice and to promote individual and family empowerment. Finally, patients also reported that their will to live and faith gave them the strength to continue with the treatment.

Conclusions

According to patients in this study, social support and the strengthening of links with family members and health professionals may reduce social exclusion and other difficulties they face, thus encouraging them to the adhere to tuberculosis treatment.

IRAK-M alters the polarity of macrophages to facilitate the survival of Mycobacterium tuberculosis

Background

Intracellular bacterium, Mycobacterium tuberculosis (M. tb), infects specifically macrophages as host cells. IRAK-M, a member of IRAK family, is a negative regulator in TLR signaling and specifically expresses in monocytes and macrophages. The role of IRAK-M in intracellular growth of M. tb and macrophage polarization was explored, for deeply understanding the pathogenesis of M. tb, the significance of IRAK-M to innate immunity and pathogen-host interaction.

Methods

IRAK-M expression was detected in M. tb infected macrophages and in human lung tissue of pulmonary tuberculosis with immunofluorescence staining, Western blot and immunohistochemistry. IRAK-M knock-down and over-expressing cell strains were constructed and intracellular survival of M. tb was investigated by acid-fast staining and colony forming units. Molecular markers of M1-type (pSTAT1 and iNOS) and M2-type (pSTAT6 and Arg-1) macrophages were detected using Western blot in IRAK-M knockdown U937 cells infected with M. tb H37Rv. U937 cells were stimulated with immunostimulant CpG7909 into M1 status and then infected with M. tb H37Rv. Expression of IRAK-M, IRAK-4 and iNOS was detected with immunofluorescence staining and Western blot, to evaluate the effect of IRAK-M to CpG directed M1-type polarization of macrophages during M. tb infection. Molecules related with macrophage’s bactericidal ability such as Hif-1 and phosphorylated ERK1/2 were detected with immunohistochemistry and Western blot.

Results

IRAK-M increased in M. tb infected macrophage cells and also in human lung tissue of pulmonary tuberculosis. IRAK-M over-expression resulted in higher bacterial load, while IRAK-M interference resulted in lower bacterial load in M. tb infected cells. During M. tb infection, IRAK-M knockdown induced M1-type, while inhibited M2-type polarization of macrophage. M1-type polarization of U937 cells induced by CpG7909 was inhibited by M. tb infection, which was reversed by IRAK-M knockdown in U937 cells. IRAK-M affected Hif-1 and MAPK signaling cascade during M. tb infection.

Conclusions

Conclusively, IRAK-M might alter the polarity of macrophages, to facilitate intracellular survival of M. tb and affect Th1-type immunity of the host, which is helpful to understanding the pathogenesis of M. tb.

Patient attitudes towards community-based tuberculosis DOT and adherence to treatment in an urban setting; Kampala, Uganda

INTRODUCTION

High Tuberculosis treatment default rate (17%) and sub-optimal treatment completion rates (45%) has burdened Kampala. Nevertheless, there are observable increase in the number of patients on TB DOT; from 6% to 29% in two consecutive annual reports. The main objective was to determine the association of TB patient attitudes towards community-based observers on the TB drug adherence on directly observed treatment for TB in Kampala.

METHODS

A cross-sectional study was carried out in Lubaga division, Kampala. A total of 201 patients in continuation phase of treatment for Pulmonary TB (i.e. 8 to 20 weeks of TB treatment) were included in the study. Patient attitudes were measured using a 4-point Likert scale aggregated into a binary outcome with ''agree'' and ''disagree'' responses. Poisson regression model using a forward fitting approach in STATA v12 was used to determine the association between patient attitude towards CB-DOTs observers and adherence to TB treatment.

RESULTS

Among the 201 patients, 66% reported their treatment was being observed by someone. Relatives were the commonest (82%) treatment observers, 26% were non adherent to their TB treatment. Perceiving ''no need for a treatment observer'' and ''people rejecting TB patients'' were predictors of non-adherence to TB treatment (IRR=1.6,95%CI 1.00-2.57;p=0.048) and (IRR=0.6, 95%CI 0.35-0.95; p=0.019) respectively.

CONCLUSION

Patient's perceived attitude and stigma towards treatment observers contribute to non-adherence on TB treatment. For improved local TB control, more emphasis is needed to build a friendly environment between treatment supporters and patients during the course of TB treatment.

QSAR based therapeutic management of M. tuberculosis

Mycobacterium tuberculosis is responsible for severe mortality and morbidity worldwide but, under-developed and developing countries are more prone to infection. In search of effective and wide-spectrum anti-tubercular agents, interdisciplinary approaches are being explored. Of the several approaches used, computer based quantitative structure activity relationship (QSAR) have gained momentum. Structure-based drug design and discovery implies a combined knowledge of accurate prediction of ligand poses with the good prediction and interpretation of statistically validated models derived from the 3D-QSAR approach. The validated models are generally used to screen a small combinatorial library of potential synthetic candidates to identify hits which further subjected to docking to filter out compounds as novel potential emerging drug molecules to address multidrug-resistant tuberculosis. Several newer models are integrated to QSAR methods which include different types of chemical and biological data, and simultaneous prediction of pharmacological activities including toxicities and/or other safety profiles to get new compounds with desired activity. In the process, several newer molecules have been identified which are now being assessed for their clinical efficacy. Present review deals with the advances made in the field highlighting overall future prospects of the development of anti-tuberculosis drugs.

Migration and infectious diseases

BACKGROUND

Infectious diseases still represent an important cause of morbidity and mortality among foreign-born individuals. The rising migration flows towards Europe throughout the last few years are raising renewed concerns about management issues and the potential associated risk for the native population.

AIMS

To discuss the health implications and challenges related to the four phases of migration, from first arrival to stable resettlement.

SOURCES

Scientific literature and relevant statistical reports.

CONTENT

Although infectious diseases are not a health priority at first arrival, a syndromic screening to identify the most common communicable conditions (pulmonary tuberculosis above all) should be promptly conducted. Reception centres where asylum seekers are gathered after arrival may be crowded, so favouring epidemic outbreaks, sometimes caused by incomplete vaccine coverage for preventable diseases. After resettlement, the prevalence of some chronic infections such as human immunodeficiency virus, viral hepatitis or tuberculosis largely reflects the epidemiological pattern in the country of origin, with poor living conditions being an additional driver. Once resettled, migrants usually travel back to their country of origin without seeking pre-travel advice, which results in a high incidence of malaria and other infections.

IMPLICATIONS

Although infectious diseases among migrants are known to have a negligible impact on European epidemiology, screening programmes need to be implemented and adapted to the different stages of the migratory process to better understand the trends and set priorities for action. Appropriate access to care regardless of the legal status is crucial to improve the health status and prevent the spread of contagious conditions.

Multidrug resistant tuberculosis in Ethiopian settings and its association with previous history of anti-tuberculosis treatment: a systematic review and meta-analysis

Background

Efforts to control the global burden of tuberculosis (TB) have been jeopardized by the rapid evolution of multi-drug resistant Mycobacterium tuberculosis (MTB), which is resistant to at least isoniazid and rifampicin. Previous studies have documented variable prevalences of multidrug-resistant tuberculosis (MDR-TB) and its risk factors in Ethiopia. Therefore, this meta-analysis is aimed, firstly, to determine the pooled prevalence of MDR-TB among newly diagnosed and previously treated TB cases, and secondly, to measure the association between MDR-TB and a history of previous anti-TB drugs treatment.

Methods

PubMed, Embase and Google Scholar databases were searched. Studies that reported a prevalence of MDR-TB among new and previously treated TB patients were selected. Studies or surveys conducted at national or sub-national level, with reported MDR-TB prevalence or sufficient data to calculate prevalence were considered for the analysis. Two authors searched and reviewed the studies for eligibility and extracted the data in pre-defined forms. Forest plots of all prevalence estimates were performed and summary estimates were also calculated using random effects models. Associations between previous TB treatment and MDR-MTB infection were examined through subgroup analyses stratified by new and previously treated patients.

Results

We identified 16 suitable studies and found an overall prevalence of MDR-TB among newly diagnosed and previously treated TB patients to be 2% (95% CI 1% - 2%) and 15% (95% CI 12% - 17%), respectively. The observed difference was statistically significant (P < 0.001) and there was an odds ratio of 8.1 (95% CI 7.5–8.7) for previously treated TB patients to develop a MDR-MTB infection compared to newly diagnosed cases. For the past 10 years (2006 to 2014) the overall MDR-TB prevalence showed a stable time trend.

Conclusions

The burden of MDR-TB remains high in Ethiopian settings, especially in previously treated TB cases. Previous TB treatment was the most powerful predictor for MDR-MTB infection. Strict compliance with anti-TB regimens and improving case detection rate are the necessary steps to tackle the problem in Ethiopia.

Breaking the barriers: Migrants and tuberculosis

Tuberculosis (TB) can represent an important clinical and public health in developing and developed countries. Low- and middle-income countries are facing an epidemic which is difficult to address because of the drug-resistance spread and the association of TB with HIV/AIDS. High-income countries, whose TB incidence has decreased in the last decades, can be involved in new TB epidemic waves owing to social, healthcare, and economic hurdles and challenges. In particular, migrants coming from high TB incidence countries can represent a new epidemiological issue in the TB care and control in geographical areas where primary care and specialized centres are not equipped to face the clinical and public health issues associated with the TB disease. The healthcare management of individuals with a latent TB infection or the TB disease is heterogeneous and different policies are in place in Europe, and, specifically, in EU countries. Scientific evidence on how to early and efficiently detect TB cases is missing, as well as diagnostic tools to diagnose those who have latent TB infection do not show adequate accuracy. Countries like Greece and Italy have political difficulties in the management of migrants and the poor living conditions in the migration centres can increase the probability of Mycobacterium tuberculosis transmission. A clear advocacy and political commitment are urgently required. The current migration trends represent a threat from a human and a healthcare perspective. New homogeneous and target-oriented policies and strategies are needed to improve the health of the migrant and of the autochthonous populations.

Changes in the Membrane-Associated Proteins of Exosomes Released from Human Macrophages after Mycobacterium tuberculosis Infection

Tuberculosis (TB) is the deadliest infectious disease worldwide. One obstacle hindering the elimination of TB is our lack of understanding of host-pathogen interactions. Exosomes, naturally loaded with microbial molecules, are circulating markers of TB. Changes in the host protein composition of exosomes from Mycobacterium tuberculosis (Mtb)-infected cells have not been described, can contribute to our understanding of the disease process, and serve as a direct source of biomarkers or as capture targets to enrich for exosomes containing microbial molecules. Here, the protein composition of exosomes from Mtb-infected and uninfected THP-1-derived macrophages was evaluated by tandem-mass-spectrometry and differences in protein abundances were assessed. Our results show that infection with Mtb leads to significant changes in the protein composition of exosomes. Specifically, 41 proteins were significantly more abundant in exosomes from Mtb-infected cells; 63% of these were predicted to be membrane associated. Thus, we used a novel biotinylation strategy to verify protein localization, and confirmed the localization of some of these proteins in the exosomal membrane. Our findings reveal another important scenario where Mtb could be influencing changes in host cells that unveil new features of the host-pathogen interaction and may also be exploited as a source of biomarkers for TB.

Splenic tuberculosis in a patient with newly diagnosed advanced HIV infection

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Splenic tuberculosis (TB) is a rare clinical condition usually seen as a part of miliary TB.

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The presence of a splenic abscess without an active TB of the lung in an Italian HIV positive patient is very uncommon.

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Case reports of isolated splenic TB in which microbiological and molecular examinations have been carried out to confirm the diagnosis are rare especially in low TB prevalence areas as Italy.

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This case report may be useful when physicians are faced with differential diagnosis of splenic mass or abscess.

The extra-pulmonary tuberculosis (TB) constitutes to about 20% of all TB cases. Among extra-pulmonary form, splenic TB is very rare clinical condition especially as initial manifestation in a developed country. Diagnosis of splenic TB is challenging because it presents no specific symptoms or typical imaging findings and microbiological confirmation is not straight forward.

We describe the case of a 55 year old Italian female with advanced HIV infection whose first AIDS clinical manifestation was a TB splenic abscess.On CT, the lesion was multilocular, hypovascular, 34 mm large, and presented contrast enhancement and a spoke wheel pattern; it was initially considered a cystic formation of parasitic nature. In this patient clinical manifestations were nonspecific (nightly fever, weight loss, and fatigue); as diagnostic imaging could not pinpoint the underlying etiology, microbiological and molecular examinations of spleen abscess drainage proved pivotal for the diagnosis. The patient improved clinically with antitubercular therapy.

The rarityof splenic tuberculosis in an European patient coupled with the involvement of the spleen in isolation and outside the “miliary” setting prompted us to report this case.

Plasma contributes to the antimicrobial activity of whole blood against Mycobacterium tuberculosis

The whole blood model for infection has proven useful to analyze the immunological response to Mycobacterium tuberculosis, because it exerts a significant antimicrobial activity. Although this activity has been generally assumed to be cellular, we have found that the leukocyte fraction of blood from healthy volunteers did not kill the bacilli. We have discovered that plasma was responsible for a large proportion, but not all, of the antimicrobial activity. Furthermore, infected monocytes controlled the mycobacterial multiplication when cultivated in the presence of plasma. Intriguingly, serum from the same donors did not share this activity, although it was able to eliminate the non-pathogenic Mycobacterium gordonae To identify the remaining components that participate in the antimycobacterial activity we fractionated blood in leukocytes, plasma, erythrocytes and platelets, and analyzed the bactericidal power of each fraction and their combinations using a factorial design. We found that erythrocytes, but not platelets, participated and showed by flow cytometry that mycobacteria physically associated with erythrocytes. We propose that in exposed healthy individuals that show 'early clearance' of the mycobacteria, the innate response is predominantly humoral, probably through the effect of antimicrobial peptides and proteins.

Molecular detection of Mycobacterium tuberculosis in cattle and buffaloes: a cause for public health concern

Tuberculosis is a re-emerging disease causing a growing public health burden. The current study was conducted to investigate the occurrence of Mycobacterium tuberculosis among cattle and buffaloes with tuberculous lesions. Typical tuberculous lesions were collected from 34 cattle and 34 buffaloes (Bubalus bubalis) through postmortem examination of slaughtered animals in abattoirs. DNAs were extracted from samples, and M. tuberculosis was identified by PCR. Positive samples were examined for resistance against rifampicin and isoniazid using GenoType MTBDRplus. Moreover, sera from 90 slaughterhouse workers, butchers, or meat inspectors were examined for the presence of M. tuberculosis antibodies using ELISA. Five cattle (14.7 %) and three buffaloes (8.8 %) tested positive. M. tuberculosis from one cattle was resistant to rifampicin and another was resistant to isoniazid. In addition, the seroprevalence of M. tuberculosis IgG among examined humans was 5.6 %. The occurrence of M. tuberculosis in cattle and buffaloes is a public health concern.

Mycobacterium smegmatis proteoliposome induce protection in a murine progressive pulmonary tuberculosis model

Tuberculosis (TB) remains an important cause of mortality and morbidity. The TB vaccine, BCG, is not fully protective against the adult form of the disease and is unable to prevent its transmission although it is still useful against severe childhood TB. Hence, the search for new vaccines is of great interest. In a previous study, we have shown that proteoliposomes obtained from Mycobacterium smegmatis (PLMs) induced cross reactive humoral and cellular response against Mycobacterium tuberculosis (Mtb) antigens. With the objective to evaluate the protective capability of PLMs, a murine model of progressive pulmonary TB was used. Animals immunized with PLMs with and without alum (PLMs/PLMsAL respectively) showed protection compared to non-immunized animals. Mice immunized with PLMsAL induced similar protection as that of BCG. Animals immunized with BCG, PLMs and PLMsAL showed a significant decrease in tissue damage (percentage of pneumonic area/lung) compared to non-immunized animals, with a more prominent effect in BCG vaccinated mice. The protective effect of the administration of PLMs in mice supports its future evaluation as experimental vaccine candidate against Mtb.

Genetic polymorphisms of IL-17A, IL-17F, TLR4 and miR-146a in association with the risk of pulmonary tuberculosis

Genetic factors affect host susceptibility to pathogens. In this population-based case control study, we explored the genetic polymorphisms of IL-17, TLR4 and miR-146a in association with pulmonary tuberculosis in a Chinese Han population. We recruited 1601 pulmonary tuberculosis patients matched with 1526 healthy controls and genotyped twelve functional single nucleotide polymorphisms (SNPs). After the correction for multiple comparisons, two SNPs (rs10759932 and rs2737190) in the TLR4 gene remained significant. Individuals carrying the rs2737190-AG genotype (vs. AA) had a significantly increased risk of either clinical tuberculosis (OR: 1.31, 95% CI: 1.11–1.53) or sputum smear-positive tuberculosis (OR: 1.35, 95% CI: 1.13–1.61). Stratification analysis revealed that the effects of genetic variations on tuberculosis were more evident among non-smokers. People with haplotype TLR4 rs10983755G–rs10759932C had a significantly increased risk of tuberculosis (OR: 3.43, 95% CI: 2.34–5.05). Moreover, we found that SNPs of rs3819024 in IL-17A and rs763780 in IL-17F were weakly related to a prognosis of tuberculosis. Our results suggest that genetic polymorphisms of IL-17 and TLR4 may play a role in host susceptibility to tuberculosis in the Chinese Han population. More work is necessary to identify specific causative variants of tuberculosis underlying the observed associations.

Lessons learnt from TB screening in closed immigration centres in Italy

Background

Between June 2012 and December 2013 Médecins Sans Frontières launched a pilot project with the aim of testing a strategy for improving timely diagnosis of active pulmonary TB among migrants hosted in four centres of identification and expulsion (CIE) in Italy.

Methods

This is a descriptive study. For active TB case finding we used an active symptom screening approach among migrants at admission in four CIE's. Here we describe the feasibility and the yield of this programme.

Results

Overall, 3588 migrants were screened, among whom 87 (2.4%) had a positive questionnaire. Out of 30 migrants referred for further investigations, three were diagnosed as having TB, or 0.1% out of 3588 individuals that underwent screening. Twenty-five (29%, 25/87) migrants with positive questionnaires were not referred for further investigation, following the doctors' decision; however, for 32 (37%, 32/87) migrants the diagnostic work-out was not completed. In multivariate analyses, being over 35 years (OR 1.7; 95% CI 1.1–2.6) and being transgender (OR 4.9; 95% CI 2.1–11.7), was associated with a positive questionnaire.

Conclusions

TB screening with symptom screening questionnaires of migrants at admission in closed centres is feasible. However, to improve the yield, follow-up of patients with symptoms or signs suggestive for TB needs to be improved.

Individual-Based Modeling of Tuberculosis in a User-Friendly Interface: Understanding the Epidemiological Role of Population Heterogeneity in a City

For millennia tuberculosis (TB) has shown a successful strategy to survive, making it one of the world’s deadliest infectious diseases. This resilient behavior is based not only on remaining hidden in most of the infected population, but also by showing slow evolution in most sick people. The course of the disease within a population is highly related to its heterogeneity. Thus, classic epidemiological approaches with a top-down perspective have not succeeded in understanding its dynamics. In the past decade a few individual-based models were built, but most of them preserved a top-down view that makes it difficult to study a heterogeneous population. We propose an individual-based model developed with a bottom-up approach to studying the dynamics of pulmonary TB in a certain population, considered constant. Individuals may belong to the following classes: healthy, infected, sick, under treatment, and treated with a probability of relapse. Several variables and parameters account for their age, origin (native or immigrant), immunodeficiency, diabetes, and other risk factors (smoking and alcoholism). The time within each infection state is controlled, and sick individuals may show a cavitated disease or not that conditions infectiousness. It was implemented in NetLogo because it allows non-modelers to perform virtual experiments with a user-friendly interface. The simulation was conducted with data from Ciutat Vella, a district of Barcelona with an incidence of 67 TB cases per 100,000 inhabitants in 2013. Several virtual experiments were performed to relate the disease dynamics with the structure of the infected subpopulation (e.g., the distribution of infected times). Moreover, the short-term effect of health control policies on modifying that structure was studied. Results show that the characteristics of the population are crucial for the local epidemiology of TB. The developed user-friendly tool is ready to test control strategies of disease in any city in the short-term.

Tackling Threats and Future Problems of Multidrug-Resistant Bacteria

With the advent of the antibiotic era, the overuse and inappropriate consumption and application of antibiotics have driven the rapid emergence of multidrug-resistant pathogens. Antimicrobial resistance increases the morbidity, mortality, length of hospitalization and healthcare costs. Among Gram-positive bacteria, Staphylococcus aureus (MRSA) and multidrug-resistant (MDR) Mycobacterium tuberculosis, and among the Gram-negative bacteria, extended-spectrum beta-lactamase (ESBLs)-producing bacteria have become a major global healthcare problem in the 21st century. The pressure to use antibiotics guarantees that the spread and prevalence of these as well as of future emerging multidrug-resistant pathogens will be a persistent phenomenon. The unfeasibility of reversing antimicrobial resistance back towards susceptibility and the critical need to treat bacterial infection in modern medicine have burdened researchers and pharmaceutical companies to develop new antimicrobials effective against these difficult-to-treat multidrug-resistant pathogens. However, it can be anticipated that antibiotic resistance will continue to develop more rapidly than new agents to treat these infections become available and a better understanding of the molecular, evolutionary and ecological mechanisms governing the spread of antibiotic resistance is needed. The only way to curb the current crisis of antimicrobial resistance will be to develop entirely novel strategies to fight these pathogens such as combining antimicrobial drugs with other agents that counteract and obstruct the antibiotic resistant mechanisms expressed by the pathogen. Furthermore, as many antibiotics are often inappropriately prescribed, a more personalized approach based on precise diagnosis tools will ensure that proper treatments can be promptly applied leading to more targeted and effective therapies. However, in more general terms, also the overall use and release of antibiotics in the environment needs to be better controlled.

5-Aza-2′-deoxycytidine enhances the antimicrobial response of vitamin D receptor against Mycobacterium tuberculosis

Objective: Epigenetic modification affects disease susceptibility.

Bibliometric analysis of worldwide publications on multi-, extensively, and totally drug - resistant tuberculosis (2006-2015)

BACKGROUND

The year 2015 marked the end of United Nations Millennium Development Goals which was aimed at halting and reversing worldwide tuberculosis (TB). The emergence of drug resistance is a major challenge for worldwide TB control. The aim of this study was to give a bibliometric overview of publications on multi-, extensively, and totally drug-resistant TB.

METHODS

Scopus database was used to retrieve articles on multidrug resistant (MDR), extensively drug-resistant (XDR), and totally drug-resistant (TDR) tuberculosis for the study period (2006-2015). The number of publications, top productive countries and institutions, citation analysis, co-authorships, international collaboration, active authors, and active journals were retrieved and analyzed.

RESULTS

A total of 2260 journal articles were retrieved. The mean ± SD citations per article was 7.04 ± 16.0. The h-index of retrieved data was 76. The number of publications showed a three - fold increase over the study period compared with less than two - fold increase in tuberculosis research during the same study period. Stratified by number of publications, the United States of America ranked first while Switzerland ranked first in productivity per 100 million people, and South Africa ranked first in productivity stratified per one trillion Gross Domestic Product. Three of the High Burden Countries (HBC) MDR-TB (India, China, and South Africa) were present in top productive countries. High percentage of international collaboration was seen among most HBC MDR-TB. Except for Plos One journal, most active journals in publishing articles on MDR, XDR, TDR-TB were in infection - related fields and in general medicine. Top 20 cited articles were published in prestigious journal such as Lancet and New England Journal of Medicine. The themes in top 20 cited articles were diverse, ranging from molecular biology, diagnostic tools, co-infection with HIV, and results of new anti-TB drugs.

CONCLUSION

Publications on MDR, XDR and TDR - TB are increasing in the past decade. International collaboration was common. Many low resourced African and Asian countries will benefit from research leading to new diagnostic and screening technology of TB. The exchange of expertise, ideas and technology is of paramount importance in this field.

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.

Public Health and Epidemiology Informatics: Recent Research and Trends in the United States

OBJECTIVES

To survey advances in public health and epidemiology informatics over the past three years.

METHODS

We conducted a review of English-language research works conducted in the domain of public health informatics (PHI), and published in MEDLINE between January 2012 and December 2014, where information and communication technology (ICT) was a primary subject, or a main component of the study methodology. Selected articles were synthesized using a thematic analysis using the Essential Services of Public Health as a typology.

RESULTS

Based on themes that emerged, we organized the advances into a model where applications that support the Essential Services are, in turn, supported by a socio-technical infrastructure that relies on government policies and ethical principles. That infrastructure, in turn, depends upon education and training of the public health workforce, development that creates novel or adapts existing infrastructure, and research that evaluates the success of the infrastructure. Finally, the persistence and growth of infrastructure depends on financial sustainability.

CONCLUSIONS

Public health informatics is a field that is growing in breadth, depth, and complexity. Several Essential Services have benefited from informatics, notably, "Monitor Health," "Diagnose & Investigate," and "Evaluate." Yet many Essential Services still have not yet benefited from advances such as maturing electronic health record systems, interoperability amongst health information systems, analytics for population health management, use of social media among consumers, and educational certification in clinical informatics. There is much work to be done to further advance the science of PHI as well as its impact on public health practice.