One‐third of the world population is estimated to have Mycobacterium tuberculosis infection. Accurate and timely identification of infected individuals is critical for treatment and control. The current diagnostic methods lack the desired sensitivity and specificity, require sophisticated equipment and skilled workforce or take weeks to yield results. Diagnosis of extrapulmonary TB, TB‐HIV co‐infection, childhood TB and sputum smear‐negative pulmonary TB pose serious challenges. Interest in developing serodiagnostic methods is increasing because detection of antibody is rapid, simple and relatively inexpensive, and does not require a living cell for detection. Three types of tests, namely screening tests to overcome diagnostic delay, specific tests for diagnosis of extrapulmonary TB and other bacteriologically negative cases, and tests for vaccine‐induced immunity need critical consideration. Several factors must be considered to develop serodiagnostic methods for TB. Antigen recognition by infected individuals is highly heterogeneous due to stage of disease, differences in HLA types, strain of the bacilli, health of the patient and bacillary load. With advances in molecular biological techniques, a number of novel antigens have been identified. Some of these antigens have proven valuable in detecting specific antibodies in some of the most challenging TB patients. The best example is a fusion protein containing several M. tuberculosis proteins (e.g. CFP‐10, MTB8, MTB48, MTB81 and the 38‐kDa protein) which showed encouraging results in detecting antibodies in sera of patients, including TB‐HIV co‐infection. This review presents progress made in the serodiagnosis of TB during the last decade.

BackgroundEarly detection and treatment of TB is essential for the success of TB control program performance. The aim of this study was to determine the length and analyze predictors of patients’, health systems’ and total delays among patients attending a referral hospital in Bahir Dar, Ethiopia.MethodsA cross-sectional study was conducted among newly diagnosed TB cases ≥ 15 years of age. Delay was analyzed at three levels: the periods between 1) onset of TB symptoms and first visit to medical provider, i.e. patients’ delay, 2) the first visit to a medical provider and the initiation of treatment i.e. health systems’ delay and 3) onset of TB symptoms and initiation of treatment i.e. total delay. Uni- and multi-variate logistic regression analyses were performed to investigate predictors of patients’, health systems’ and total delays.ResultsThe median time of patients’ delay was 21 days [(interquartile range (IQR) (7 days, 60 days)]. The median health systems’ delay was 27 days (IQR 8 days, 60 days) and the median total delay was 60 days (IQR 30 days, 121 days). Patients residing in rural areas had a three-fold increase in patients’ delay compared to those from urban areas [Adjusted Odds Ratio (AOR) 3.4; 95% (CI 1.3, 8.9)]. Extra-pulmonary TB (EPTB) cases were more likely to experience delay in seeking treatment compared to pulmonary (PTB) cases [(AOR 2.6; 95% (CI 1.3, 5.4)]. Study subjects who first visited health centres [(AOR) 5.1; 95% (CI 2.1, 12.5)], private facilities [(AOR) 3.5; 95% (CI 1.3, 9.7] and health posts [(AOR) 109; 95% (CI 12, 958], were more likely to experience an increase in health systems’ delay compared to those who visited hospitals.ConclusionsThe majority of TB patients reported to medical providers within an acceptable time after the onset of symptoms. Rural residence was associated with patients’ and total delays. Providing the population with information about TB symptoms and the importance of early health seeking may be an efficient way to decrease TB transmission, morbidity and mortality. Establishing efficient TB diagnostic and treatment facilities at the periphery level is imperative to reduce diagnostic delay and expedite TB treatment.

BackgroundHealth care seeking is a dynamic process that is influenced by socio-demographic, cultural and other factors. In Ethiopia, there are limited studies regarding the health seeking behaviour of tuberculosis (TB) suspects and TB patients. However, a thorough understanding of patients' motivation and actions is crucial to understanding TB and the treatment of disease. Such insights would conceivably help to reduce delay in diagnosis, improve treatment adherence and thereby reduce transmission of TB in the community. The objective of this study was to describe and analyze health care seeking among TB suspects and pulmonary TB (PTB) cases in a rural district of the Amhara Region in Ethiopia.MethodsStudy kebeles were randomly selected in a cross-sectional study design. House-to-house visits were conducted in which individuals aged 15 years and above in all households of the kebeles were included. Subjects with symptoms suggestive of TB were interviewed about their health seeking behaviour, socio-demographic and clinical factors using a semi-structured questionnaire. Logistics regression analysis was employed to assess associations between the independent and outcome variables.ResultsThe majority, 787 (78%), TB suspects and 33 (82.5%) PTB cases had taken health care actions for symptoms from sources outside their homes. The median delay before the first action was 30 days. In logistics regression, women (AOR 0.8, 95% CI 0.6, 0.9) were found to be less likely to visit a medical health provider than men. Those with a long duration of cough (AOR 1.5, 95% CI 1.03, 2.1) and those with a previous history of TB (AOR 1.5, 95% CI 1.03, 2.3) were more likely to visit a medical health provider compared to those with a shorter duration of cough and with no history of TB.ConclusionThe majority of TB suspects and PTB cases had already taken health care actions for their symptoms at the time of the survey. The availability of a simple and rapid diagnostic TB test for use at the lowest level of health care and the involvement of all health providers in case finding activities are imperative for early TB case detection.

f Recent genotyping studies of Mycobacterium tuberculosis in Ethiopia have reported the identification of a new phylogenetically distinct M. tuberculosis lineage, lineage 7. We therefore investigated the genetic diversity and association of specific M. tuberculosis lineages with sociodemographic and clinical parameters among pulmonary TB patients in the Amhara Region, Ethiopia. DNA was isolated from M. tuberculosis-positive sputum specimens (n ‫؍‬ 240) and analyzed by PCR and 24-locus mycobacterial interspersed repetitive unit-variable-number tandem-repeat (MIRU-VNTR) analysis and spoligotyping. Bioinformatic analysis assigned the M. tuberculosis genotypes to global lineages, and associations between patient characteristics and genotype were evaluated using logistic regression analysis. The study revealed a high diversity of modern and premodern M. tuberculosis lineages, among which approximately 25% were not previously reported. Among the M. tuberculosis strains (n ‫؍‬ 138) assigned to seven subgroups, the largest cluster belonged to the lineage Central Asian (CAS) (n ‫؍‬ 60; 26.0%), the second largest to lineage 7 (n ‫؍‬ 36; 15.6%), and the third largest to the lineage Haarlem (n ‫؍‬ 35; 15.2%). Four sublineages were new in the MIRU-VNTRplus database, designated NW-ETH3, NW-ETH1, NW-ETH2, and NW-ETH4, which included 24 (10.4%), 18 (7.8%), 8 (3.5%), and 5 (2.2%) isolates, respectively. Notably, patient delay in seeking treatment was significantly longer among patients infected with lineage 7 strains (Mann-Whitney test, P < 0.008) than in patients infected with CAS strains (adjusted odds ratio [AOR], 4.7; 95% confidence interval [CI], 1.6 to 13.5). Lineage 7 strains also grew more slowly than other M. tuberculosis strains. Cases of Haarlem (OR, 2.8; 95% CI, 1.2 to 6.6) and NW-ETH3 (OR, 2.8; 95% CI, 1.0 to 7.3) infection appeared in defined clusters. Intensified active case finding and contact tracing activities in the study region are needed to expedite diagnosis and treatment of TB.

Multiple regulatory mechanisms including post-translational modifications (PTMs) confer complexity to the simpler genomes and proteomes of Mycobacterium tuberculosis (Mtb). PTMs such as glycosylation play a significant role in Mtb adaptive processes. The glycoproteomic patterns of clinical isolates of the Mycobacterium tuberculosis complex (MTBC) representing the lineages 3, 4, 5 and 7 were characterized by mass spectrometry. A total of 2944 glycosylation events were discovered in 1325 proteins. This data set represents the highest number of glycosylated proteins identified in Mtb to date. O-glycosylation constituted 83% of the events identified, while 17% of the sites were N-glycosylated. This is the first report on N-linked protein glycosylation in Mtb and in Gram-positive bacteria. Collectively, the bulk of Mtb glycoproteins are involved in cell envelope biosynthesis, fatty acid and lipid metabolism, two-component systems, and pathogen-host interaction that are either surface exposed or located in the cell wall. Quantitative glycoproteomic analysis revealed that 101 sites on 67 proteins involved in Mtb fitness and survival were differentially glycosylated between the four lineages, among which 64% were cell envelope and membrane proteins. The differential glycosylation pattern may contribute to phenotypic variabilities across Mtb lineages. The study identified several clinically important membrane-associated glycolipoproteins that are relevant for diagnostics as well as for drug and vaccine discovery.