Review of multidrug-resistant and extensively drug-resistant TB: global perspectives with a focus on sub-Saharan Africa

Factors associated with tuberculosis drug resistance among presumptive multidrug resistance tuberculosis patients identified in a DRTB surveillance study in western Kenya

Multidrug-resistant tuberculosis (MDR-TB) is caused by M. tuberculosis (Mtb) with resistance to the first-line anti-TB medicines isoniazid (INH) and rifampicin (RIF). In Western Kenya, there is reported low prevalence of drug resistant strains among HIV tuberculosis patients, creating a need to determine factors associated with drug resistance patterns among presumptive MDR-TB patients. To determine factors associated with drug resistance patterns among presumptive MDR-TB patients in western Kenya. Three hundred and ninety (3 9 0) sputum sample isolates from among presumptive multidrug TB patients, were analyzed for TB drug resistance as per Ministry of Health (MoH) TB program diagnostic algorithm. Frequency and percentages were used to summarize categorical data while median and interquartile range (IQR) were used for continuous data. Multivariable logistic regression was carried out to identify factors associated with TB drug resistance. Out of 390 participants enrolled, 302/390 (77.4 %) were males, with a median age of 34 years. The HIV-infected were 118/390 (30.3 %). Samples included 322 (82.6 %) from presumptive patients, while 68/390 (17.4 %) were either lost to follow-up patients, failures to first-line treatment or newly diagnosed cases. A total of 64/390 (16.4 %) of the isolates had at least some form of drug resistance. Out of 390, 14/390 (3.6 %) had MDR, 12 (3.1 %) were RIF mono-resistance, 34 (8.7 %) had INH, while 4 (1 %) had ethambutol resistance. The category of previously treated patients (those who received or are currently on TB treatment) had a 70 % reduced likelihood of resistance (aOR: 0.30; 95 % CI: 0.13-0.70). In contrast, older age was associated with an increased likelihood of resistance to INH and RIF, with an adjusted odds ratio of 1.04 per year (95 % CI: 1.00-1.08). Prompt MDR-TB diagnosis is essential for appropriate patient care, management, and disease prevention and control. We recommend active surveillance on drug resistant TB in these regions to detect drug resistance patterns for rapid disease management.

The Association of Chronic Pulmonary Aspergillosis and Chronic Pulmonary Histoplasmosis with MDR-TB Patients in Indonesia

In Indonesia, 2.4% of all new tuberculosis patients had multi-drug resistant disease (MDR-TB); an estimated 24,000 incidences. Historical case series of MDR-TB described a high frequency of cavitation and poor prognosis. The diagnosis of chronic pulmonary aspergillosis (CPA) relies on raised levels of Aspergillus IgG antibodies, and detectable Histoplasma IgG antibodies are suspicious for chronic pulmonary histoplasmosis (CPH). We investigated whether MDR-TB patients might have concurrent CPH or CPA. This was a cross-sectional study with 50 MDR-TB patients. ELISA was used to detect Histoplasma IgG antibodies and lateral flow assay was used to detect Aspergillus IgG/IgM antibodies. Several other possible disease determinants were assessed by multivariate analysis. Of the 50 MDR-TB patients, 14 (28%) and 16 (32%) had positive Histoplasma or Aspergillus serology; six patients (12%) had dual antibody reactivity. Radiological abnormalities in positive patients included diffuse or local infiltrates, nodules, consolidation, and apical cavities, consistent with CPH and CPA. Patients with detectable fungal antibodies tended to have worse disease, and 4 of 26 (15.3%) died in the first 5 months of dual infection (p = 0.11 compared with no deaths in those with only MDR-TB). The criteria for the diagnosis of CPH and CPA were fulfilled in those with moderately and far advanced disease (13 of 14 or 93%) and 12 of 16 (75%), respectively. Damp housing was the only determinant associated with Histoplasma antibodies (PR 2.01; 95%CI 0.56-7.19), while pets were associated with the Aspergillus antibody (PR 18.024; 95%CI 1.594-203.744). CPA or CPH are probably frequent in MDR-TB patients in Indonesia and may carry a worse prognosis.

Determinants of multidrug-resistant tuberculosis among adults undergoing treatment for tuberculosis in Tigray Region, Ethiopia: a case-control study

BACKGROUND

Multidrug-resistant tuberculosis is a type of tuberculosis that is resistant to at least the first-line antituberculosis drugs namely, rifampicin and isoniazid. However, most of these studies were limited only to a single hospital. Therefore, this study aimed to identify the determinants of multidrug-resistant tuberculosis among adults undergoing treatment for tuberculosis in the Tigray region of Ethiopia.

METHODS

Hospital-based unmatched case-control study was conducted from 1 April 2019 to 30 June 2019. A simple random sampling method was used to select the required sample size. Variables at a p value less than 0.25 in bivariate analysis were entered into a multivariable analysis to identify the determinant factors of multidrug-resistant tuberculosis. Finally, the level of significance was declared at p<0.05.

RESULTS

Rural residence (adjusted OR (AOR) 2.54; 95% CI 1.34 to 4.83), HIV (AOR 4.5; 95% CI 1.4 to 14.2), relapse (AOR 3.86; 95% CI 1.98 to 7.5), return after lost follow-up (AOR 6.29; 95% CI 1.64 to 24.2), treatment failure (AOR 5.87; 95% CI 1.39 to 24.8) were among the determinants of multidrug-resistant tuberculosis.

CONCLUSION

Rural residence, HIV, relapses, return after lost follow-up and treatment failure were the identified determinant factors of multidrug-resistance tuberculosis.

WHO's end of TB targets: unachievable by 2035 without addressing under nutrition, forced displacement, and homelessness: trend analysis from 2015 to 2022

Tuberculosis (TB) remains a significant global health challenge, despite the World Health Organization (WHO) actively working towards its eradication through various initiatives and programs. Undernutrition, forced displacement, and homelessness worsen TB's burden and challenge control efforts; however, there is still no adequate research that shows the trend of these underlying factors to attain the WHO's ambitious TB targets. So, this study aims to analyze the trend analysis of these underlying factors worldwide from 2015 to 2022 and their impact on the feasibility and implications of reaching the End TB targets by 2035. We utilized international databases, including UNHCR, FAO, and WHO reports, as secondary data sources. Data were extracted chronologically from 2015 to 2022 to illustrate trends in undernutrition, forced displacement, and homelessness on a global level.This trend analysis reveals that undernutrition, forced displacement, and homelessness have worsened over time. Undernutrition rose from 8.4 to 9.8% globally between 2015 and 2021, affecting 22.7 million additional individuals each year. In 2022, undernutrition affected 735 million people globally. Africa (21.9%) and Asia (10.6%) had the highest rates, while Western Europe and North America had lower rates than the global average: 3.4% and 2.5%, respectively.Similarly, the global rate of forced displacement increased from 65.1 million people in 2015 to 108.4 million in 2022, a 21% increase from 2021. This means that an extra 19 million people were displaced in 2021. Globally, homelessness, affecting 1.6 billion people, has worsened over time. Despite being a highly vulnerable group to TB, homeless individuals are often neglected in TB control efforts. Our findings underscore the critical importance of addressing undernutrition, forced displacement, and homelessness in achieving the World Health Organization's ambitious End TB targets by 2035, as highlighted through trend analysis from 2015 to 2022. Implementing policies focusing on nutrition, stable housing, and the challenges faced by displaced populations is imperative for progress toward a TB-free world.

Risk factors for multidrug-resistant tuberculosis in the Central African Republic: A case-control study

BACKGROUND

The emergence and spread of multidrug-resistant tuberculosis (MDR-TB) presents a challenge to the "End TB by 2035" strategy. This study aimed to identify the risk factors associated with MDR-TB in patients admitted to the pneumo-physiology clinic of the National University Hospital of Bangui in Central African Republic.

METHODS

This was a "retrospective" chart review study. Cases were represented by patients more than 18 years of age treated for MDR-TB and controls were patients with "at least rifampicin-susceptible" TB treated "with first-line anti-TB regimen" and who at the end of treatment were declared cured. The status of "cured" was exclusively applicable to non-MDR TB. Risk factors associated with MDR-TB were identified by multivariate analysis.

RESULTS

We included 70 cases and 140 controls. The median age was 35 years, IQR (22;46 years). The main factors associated with the occurrence of MDR-TB in multivariate analysis were male gender (0 R = 3.02 [1.89-3.99], p = 0.001), residence in a peri-urban/urban area (0 R = 3.06 [2.21-4.01], p = 0.002), history of previous TB treatment (0 R= 3.99 [2.77-4.25], p < 0.001) and the presence of multidrug-resistant TB in the family (0 R=1.86 [1.27-2.45], p = 0.021).

CONCLUSION

The emergence of MDR-TB can be reduced by implementing appropriate strategies, such as preventive therapy in contacts of MDR-TB patients and detecting and appropriately treating MDR-TB patients to prevent further spread of infection.

Global prevalence of drug-resistant tuberculosis: a systematic review and meta-analysis

BACKGROUND

Tuberculosis is a bacterial infectious disease, which affects different parts of a human body, mainly lungs and can lead to the patient's death. The aim of this study is to investigate the global prevalence of drug-resistant tuberculosis using a systematic review and meta-analysis.

METHODS

In this study, the PubMed, Scopus, Web of Science, Embase, ScienceDirect and Google Scholar repositories were systematically searched to find studies reporting the global prevalence of drug-resistant tuberculosis. The search did not entail a lower time limit, and articles published up until August 2022 were considered. Random effects model was used to perform the analysis. The heterogeneity of the studies was examined with the I² test. Data analysis was conducted within the Comprehensive Meta-Analysis software.

RESULTS

In the review of 148 studies with a sample size of 318,430 people, the I² index showed high heterogeneity (I² = 99.6), and accordingly random effects method was used to analyze the results. Publication bias was also examined using the Begg and Mazumdar correlation test which indicated the existence of publication bias in the studies (P = 0.008). According to our meta-analysis, the global pooled prevalence of multi-drug resistant TB is 11.6% (95% CI: 9.1-14.5%).

CONCLUSIONS

The global prevalence of drug-resistant tuberculosis was found to be very high, thus health authorities should consider ways to control and manage the disease to prevent a wider spread of tuberculosis and potentially subsequent deaths.

Modified gold nanoparticle colorimetric probe-based biosensor for direct and rapid detection of Mycobacterium tuberculosis in sputum specimens

The incidence of Mycobacterium tuberculosis (MTB) is increasing due to lack of appropriate diagnostic and therapeutic methods. Therefore, early and accurate detection of this bacteria plays a significant role in controlling tuberculosis. This study aimed to design, develop, and implement a direct and rapid detection method of MTB using modified gold nanoparticle (AuNP) colorimetric probe-based biosensor in sputum specimens. Spherical AuNPs were synthesized by the citrate reduction method and were functionalized using thiol-modified oligonucleotides (AuNP-biosensor). AuNP-biosensor and IS6110 PCR were compared to the gold standard in terms of analytical and clinical sensitivity and specificity, positive predictive value (PPV), negative predictive value (NPV), diagnostic odds ratio (DOR), and accuracy in 52 clinical specimens. Gold standard was defined as a positive result in concentrated sputum smear microscopy (SSM), culture, or Xpert MTB/RIF.The AuNP-biosensor had 100% sensitivity and specificity for detection of total sputum DNA in less than 15 min with ready-to-use AuNP-biosensor. PPV, NPV, DOR and accuracy of this method were 100%, 100%, 2325 and 100%, respectively. Considering the promising results of the diagnostic value indices of the AuNP-biosensor, the designed method is an affordable, rapid, reliable, and cost-beneficial way for direct detection of MTB in sputum specimens.

First and Second-Line Anti-Tuberculosis Drug-Resistance Patterns in Pulmonary Tuberculosis Patients in Zambia

BACKGROUND

Drug-resistant tuberculosis has continued to be a serious global health threat defined by complexity as well as higher morbidity and mortality wherever it occurs, Zambia included. However, the paucity of information on drug-susceptibility patterns of both first-line and second-line anti-tuberculosis (anti-TB) drugs, including the new and repurposed drugs used in the management of drug-resistant tuberculosis in Zambia, was the major thrust for conducting this study.

METHODS

A total of 132 bacteriologically confirmed TB isolates were collected from patients with pulmonary TB during the period from April 2020 to December 2021 in Southern and Eastern Provinces of Zambia. Drug-resistance profiles were determined according to four first-line and five second-line anti-TB drugs. Standard mycobacteriological methods were used to isolate and determine phenotypic drug susceptibility. Data on the participants' social-demographic characteristics were obtained using a pre-test checklist.

RESULTS

Overall, the prevalence of resistance to one or more anti-TB drugs was 23.5% (31/132, 95% CI: 16.5-31.6%). A total of 9.8% (13/132, 95% CI: 5.3-16.2%) of the patients had multidrug-resistant TB and 1.2% were new cases, while 25.5% had a history of being previously treated for TB. Among those with mono-resistant TB strains, isoniazid (INH) resistance was the highest at 9.8% (13/132, 95% CI: 5.3-16.2%). Two (2/31) (6.5%) XDR-TB and one (1/31) (3.2%) pre-XDR-TB cases were identified among the MDR-TB patients. Previously treated patients were 40 times more likely (OR; 40.3, 95% CI: 11.1-146.5%) to have drug-resistant TB than those who had no history of being treated for TB.

CONCLUSION

This study has established a high rate of multidrug-resistant TB and has further identified both pre-XDR- and XDR-TB. There is a need to intensify surveillance of MDR- and XDR-TB to inform future guidelines for effective treatment and monitoring.

Whole-genome sequencing of presumptive MDR-TB isolates from a tertiary healthcare setting in Mumbai

OBJECTIVES

Whole-genome sequencing (WGS) of Mycobacterium tuberculosis (MTB), proven to be a better alternative when compared with the combined sensitivity and specificity of all other modalities for diagnosis of tuberculosis (TB), aids epidemiological surveillance investigations by combining the current research with diagnostics. This study was conducted to identify and resolve operational challenges in performing WGS-based drug resistance testing (DRT) for MTB in a TB culture and drug susceptibility testing (DST) laboratory. Three critical, non-redundant steps for WGS-based DRT were tested: viz. DNA extraction, high-throughput paired-end next-generation sequencing (NGS), and genomic analysis pipeline for automated reporting of WGS-based DRT.

METHODS

DNA was extracted from 100 liquid culture isolates on a mycobacterial growth indicator tube (MGIT) using DNEASY Ultraclean Microbial Kit (Qiagen, USA) as per the manufacturer's instructions. Illumina paired-end sequencing was performed. All analysis steps were automated using custom python scripts, requiring no intervention. Variant calling was performed as per the World Health Organization (WHO) technical guide.

RESULTS

The number of cultures resistant to rifampicin, isoniazid, pyrazinamide, ethambutol, and streptomycin was 89, 88, 35, 67, and 73, respectively. Resistance to amikacin, kanamycin, and capreomycin was found in 15, 17, and 15 cultures, respectively. Seventy cultures were resistant to fluoroquinolones, four were resistant to ethionamide, and 12 were resistant to linezolid. Six cultures were resistant to only one of the 18 drugs tested. Seventy-five cultures were resistant to more than three anti-TB drugs. One culture was resistant to 13 of the 18 anti-TB drugs tested for this study. The maximum number of variants were observed in the rpoB gene (n = 93, 93%), wherein the Ser450Leu was the predominant mutation (n = 68, 73%). Ser315Thr was the most common variant (n = 86, 97%) that encoded resistance to isoniazid. The Lys43Arg variant encodes resistance to streptomycin and was the third most predominant variant (n = 65, 89%). In addition to the high levels of resistance observed in the dataset, we also observed a high proportion of Beijing strains (n = 63, 63%).

CONCLUSION

Compared with results from routine diagnostics based on the 'Guidelines on Programmatic Management of Drug-Resistant TB (PMDT) in India', none of the samples had DST available for all 18 drugs. This represents a gap in PMDT guidelines. The WGS-DRT must be considered as the primary DST method after a sample is flagged rifampicin-resistant by cartridge-based nucleic acid amplification testing (CBNAAT). With several research studies currently underway globally to identify novel variants associated with drug resistance and classifiy their minimum inhibitory coefficients, WGS-DRT presents a scalable technology that updates analytical pipelines, relegating the need for changing microbiological protocols.

Resistance patterns among drug-resistant tuberculosis patients and trends-over-time analysis of national surveillance data in Gabon, Central Africa

Objective

Routinely generated surveillance data are important for monitoring the effectiveness of MDR-TB control strategies. Incidence of rifampicin-resistant tuberculosis (RR-TB) is a key indicator for monitoring MDR-TB.

Methods

In a longitudinal nationwide retrospective study, 8 years (2014–2021) of sputum samples from presumptively drug-resistant tuberculosis patients from all regions of Gabon were referred to the national tuberculosis reference laboratory. Samples were analysed using GeneXpert MTB/RIF and Genotype MTBDRsl version 2/Line Probe Assay.

Results

Of 3057 sputum samples from presumptive tuberculosis patients, both from local hospital and from referral patients, 334 were RR-TB. The median patient age was 33 years (interquartile range 26–43); one third was newly diagnosed drug-resistant tuberculosis patients; one-third was HIV-positive. The proportion of men with RR-TB was significantly higher than that of women (55% vs 45%; p < 0.0001). Patients aged 25–35 years were most affected (32%; 108/334). The cumulative incidence of RR-TB was 17 (95% CI 15–19)/100,000 population over 8 years. The highest incidences were observed in 2020 and 2021. A total of 281 samples were analysed for second-line drug resistance. The proportions of study participants with MDR-TB, pre-XDR-TB and XDR-TB were 90.7% (255/281), 9% (25/281) and 0.3% (1/281), respectively. The most-common mutations in fluoroquinolones resistance isolates was gyrA double mutation gyrA MUT3B and MUT3C (23%; 4/17). Most (64%; 6/8) second-line injectable drugs resistance isolates were characterised by missing both rrs WT2 and MUT2 banding.

Conclusion

The increasing incidence of MDR-TB infection in Gabon is alarming. It is highest in the 25–35 years age category. The incidence of MDR-TB infection in treatment-naïve patients calls for case finding and contact tracing strategy improvement.

Treatment Outcome of MDR/RR TB in a Resource-Constrained Setup: A Four-Year Retrospective Analysis

Introduction

The emergence of drug resistance in TB treatment is a major public health threat. However, there are limited studies which are directed towards identifying factors that explain the gap in achieving treatment targets.

Objective

: This study aimed to assess the treatment outcome and its associated factors among patients with MDR/RR-TB in Dilchora Hospital Treatment Initiation Center from January 2014 to December 2018.

Method

: A retrospective cross-sectional study was conducted on patients with MDR/RR TB who initiated treatment between January 2014 and December 2018. Data were extracted from patient medical charts using a structured questionnaire. SPSS version 26 was used for analysis. Reports are presented using percentages and frequency. Independently associated factors for unfavorable outcome were identified using binary logistic regression model. Adjusted and crude odds ratio with 95% CI was used. P-value less than 0.05 was used to declare statistical significance.

Result

: A total of 146 patients were included in this study. The overall prevalence of unfavorable outcomes in this study for those with known outcomes was 8.6%. People living with HIV had a 6.47 times (95% CI: 1.14–36.68) increased odds of death as compared to those who are HIV negative. For every 1kg/m² increment in BMI, there was a 35.3% (AOR = 0.647; CI: 0.44–0.95) reduction in the odds of death as compared to those who had a 1kg/m2 lower BMI. Each additional month without culture conversion also increased the odds of death 2.24 times (95%CI: 1.08–4.66).

Conclusion & Recommendation

: The findings of our study showed an appreciably low poor treatment outcome for this outpatient program. HIV screening and early initiation of HAART, early identification and treatment of those who are underweight and a critical follow-up to the time of sputum culture conversion could help in further improving the outcomes.

Prevalence of multidrug-resistant tuberculosis in East Africa: A systematic review and meta-analysis

Background

The rate of multidrug-resistant tuberculosis is increasing at an alarming rate throughout the world. It is becoming an emerging public health problem in East Africa. The prevalence of multidrug-resistant tuberculosis among pulmonary tuberculosis positive individuals in the region has not been thoroughly investigated.

Aim

The aim of this systematic review and meta-analysis is to estimate the pooled prevalence of multidrug-resistant tuberculosis among newly diagnosed and previously treated pulmonary tuberculosis cases in East African countries.

Methods

English published articles were systematically searched from six electronic databases: PubMed, EMBASE, Scopus, Science direct, Web of Science, and Google scholar. The pooled prevalence of multidrug-resistant tuberculosis and associated risk factors were calculated using Der Simonian and Laird’s random Effects model. Funnel plot symmetry visualization confirmed by Egger’s regression asymmetry test and Begg rank correlation methods was used to assess publication bias. A total of 16 articles published from 2007 to 2019 were included in this study. STATA 14 software was used for analysis.

Results

Out of 1025 articles identified citations, a total of 16 articles were included in final meta-analysis. The pooled prevalence of multidrug-resistant tuberculosis among newly diagnosed tuberculosis cases and previously treated tuberculosis patients was 4% (95%CI = 2–5%) and 21% (95%CI: 14–28%), respectively. Living conditions, lifestyles (smoking, alcohol use, and drug abuse), previous medical history, diabetes history, and human immunodeficiency virus infection were risk factors contributing to the higher prevalence of multidrug-resistant tuberculosis in East Africa.

Conclusion

The review found a significant prevalence of multidrug-resistant tuberculosis in the region. An early diagnosis of tuberculosis and rapid detection of drug-resistant Mycobacterium tuberculosis is a critical priority to identify patients who are not responding to the standard treatment and to avoid transmission of resistant strains. It is also very important to strengthen tuberculosis control and improve monitoring of chemotherapy.

Visualizing the Knowledge Base and Research Hotspot of Public Health Emergency Management: A Science Mapping Analysis-Based Study

Public health emergency management has been one of the main challenges of social sustainable development since the beginning of the 21st century. Research on public health emergency management is becoming a common focus of scholars. In recent years, the literature associated with public health emergency management has grown rapidly, but few studies have used a bibliometric analysis and visualization approach to conduct deep mining and explore the characteristics of the public health emergency management research field. To better understand the present status and development of public health emergency management research, and to explore the knowledge base and research hotspots, the bibliometric method and science mapping technology were adopted to visually evaluate the knowledge structure and research trends in the field of public health emergency management studies. From 2000 to 2020, a total of 3723 papers related to public health emergency management research were collected from the Web of Science Core Collection as research data. The five main research directions formed are child prevention, mortality from public health events, public health emergency preparedness, public health emergency management, and coronavirus disease 2019 (COVID-19). The current research hotspots and frontiers are climate change, COVID-19 and related coronaviruses. Further research is needed to focus on the COVID-19 and related coronaviruses. This study intends to contribute inclusive support to related academia and industry in the aspects of public health emergency management and public safety research, as well as research hotspots and future research directions.

Knowledge Mapping Analysis of Public Health Emergency Management Research Based on Web of Science

At present, major public health emergencies frequently occur worldwide, and it is of great significance to analyze the research status and latest developments in this field to improve the ability of public health emergency management in various countries. This paper took 5,143 related studies from 2007 to 2020 from the Web of Science as research object and used CiteSpace, VOSviewer, and other software to perform co-word analysis, social network analysis, and cluster analysis. The results and conclusions were as follows: (1) the related research identified three periods: the exploration, growth, and outbreak period; (2) chronologically: the relevant research evolved from medical and health care for major diseases to emergency management and risk assessment of public health emergencies and then researched the novel coronavirus (COVID-19) pneumonia epidemic; (3) clustering analysis of high-frequency keywords, identifying three research hotspots: “disaster prevention and emergency medical services,” “outbreak and management of infectious diseases in Africa,” and “emergency management under the COVID-19 pneumonia epidemic.” Finally, this study combined the data and literature analysis to point out possible future research directions: from the research of the COVID-19 pneumonia epidemic to the research of general major public health emergencies, thinking and remodeling of the national public health emergency management system, and exploring the establishment of an efficient international emergency management cooperation mechanism.

Drug Resistant Tuberculosis in the Northern Region of Zambia: A Retrospective Study

Background

Zambia like many countries in sub-Saharan Africa is affected with drug resistant tuberculosis. However, the drug resistant tuberculosis situation over the years has not been described in various regions of the country. Consequently, this study aims to determine the drug resistant tuberculosis burden in northern regions of Zambia over a four-year period based on data generated from a Regional Tuberculosis Reference Laboratory.

Method

Two hundred and thirty two (232) Tuberculosis Drug Susceptibility Testing results over a four-year period (2016-2019) were reviewed. Data was collected from tuberculosis registers and patient request forms and entered into a pre-tested standardized checklist and later entered in Excel Computer software. Double blinded checking was done by two independent data clerks to minimize duplication of cases. Cleaned data was then imported in R programme for analysis. Bivariant and descriptive statistics were performed and reported.

Results

Of 232 Drug Susceptibility Testing results, 90.9% were drug resistant TB while 9% were drug susceptible. Fifty three percent (53%) of these were multi-drug resistant Tuberculosis and 32% were confirmed as Rifampicin Mono-resistance. Only 1.7% of the Multi-drug resistant Tuberculosis patients were Pre-extensively drug-resistant Tuberculosis. Copperbelt province had the largest proportion (46.0%) of multi-drug resistant tuberculosis patients followed by Luapula (8.1%) and North-Western (4.7%) provinces. In new and previously treated patients, the proportion of Multi-drug resistant tuberculosis was 71.8% and 28.7% respectively. History of previous anti-tuberculosis treatment and treatment failure were associated with multi-drug resistance TB.

Conclusion and Recommendation

This study has shown a small increase in the proportions of drug resistant tuberculosis cases over the four years under review with high rates being recorded on the Copperbelt Province. Previous treatment to first line TB treatment and treatment failure were associated with development of Multi-drug resistance. We therefore recommend strengthened routine laboratory surveillance and improved case management of multi-drug resistant tuberculosis patients in the region.

The Magnitude of MTB and Rifampicin Resistance MTB Using Xpert-MTB/RIF Assay Among Tuberculosis Suspected Patients in Gedeo Zone, Southern Ethiopia

Background

Tuberculosis (TB) remains a major global health problem causing death among millions of people each year. The new barrier that challenges the control of tuberculosis is the emerging and the increasing number of drug-resistant TB that becomes a world concern. This study aimed to determine the magnitude of rifampicin-resistant Mycobacterium tuberculosis (RR-MTB) among presumptive TB patients attending Dilla University Referral Hospital, Gedeo Zone, Ethiopia.

Methods

A retrospective cross-sectional study was conducted at Dilla University Referral Hospital from January 2014 to December 2020. Sputum results were done using Xpert MTB/RIF assay and other necessary data were collected from the registration logbooks using a standardized data extraction format and analyzed using SPSS version 23 statistical software.

Results

A total of 17,745 presumptive TB patients were included, of which 62.2% were males. The overall prevalence of Mycobacterium tuberculosis (MTB) was 11.8%, of which 5.1% were confirmed to have RR-MTB. Extra-pulmonary TB was reported in 1.5% of the study participants. The highest prevalence of MTB and RR-MTB was recorded in 2017 with a prevalence of 20.1% and 8.5%, respectively. All age groups were significantly associated with a higher prevalence of MTB (p < 0.036). TB patients with a history of previous treatment and HIV positive were significantly associated with MTB (P < 0.021), while RR-MTB was only significantly associated with patients with a history of previous treatment (P < 0.018).

Conclusion

A high magnitude of MTB and RR-MTB was reported among TB patients with HIV and a history of previous treatment. Therefore, coordinated efforts should be applied to the improvement of treatment adherence of known TB cases, and appropriate control and prevention methods to reduce the emergence and increase of MTB and RR-MTB cases.

Factors Associated with Multi-Drug Resistant Tuberculosis among TB Patients in Selected Treatment Centers of Amhara Region: A Case-Control Study

Background

Multi-drug Resistant Tuberculosis (MDR-TB) is found to be a major public health problem both in developed and developing countries. Ethiopia is one of the 30 high MDR-TB burden countries in the world. Although several studies were done to identify the determinants of MDR-TB, the reported findings are heterogeneous across the world.

Methods

Unmatched case-control study was conducted at Debre Markose Referral Hospital, Debre Birhan Referral Hospital, and Boru Media District Hospital in Amhara Region, Northern Ethiopia, from March 01/2019- April 30/2019. Cases were all tuberculosis patients with culture or line probe assay confirmed mycobacterium tuberculosis resistant to at least both Isoniazid and Rifampicin and registered on second-line TB treatment. Controls were all patients with Bacteriological (molecular) proven drug-susceptible TB strains and whose recent smears result were turned to negative and registered as cured from January 01/2014 – December 31/2018. A pre-tested checklist was used to collect the data.

Result

Of the total reviewed documents (393), 98 cases and 295 controls were involved in this study. And, 54(55.1%) among cases and 162(54.9%) among controls were males. sixty nine(70.4%) among cases and 163(55.3) among controls were within the age group of 26–45 years. In the multivariable logistic regression analysis, age between 26–45 years old (AOR=3.35; 95% CI: 1.15, 9.77), previous history of TB treatment (AOR= 14.2; 95%CI: 7.8, 25.3) and being HIV positive (AOR=4.4; 95% CI: 1.8, 10.4) were significantly associated with MDR-TB.

Conclusion

Age between 26–45 years old, previously treated cases and TB/HIV co-infection were identified as the determinants of MDR-TB. Special attention should be given to age between 26–45 years old, previous history of TB treatment and TB/HIV co-infection to prevent and control MDR-TB in the local context.

Chronic Pulmonary Histoplasmosis-A Scoping Literature Review

Chronic pulmonary histoplasmosis (CPH) is an uncommon manifestation of Histoplasma infection with features similar to pulmonary tuberculosis (TB). In endemic areas, it may be misdiagnosed as smear-negative pulmonary TB. Historical case series mainly from patients with presumed TB described a high frequency of cavitation and poor prognosis, likely resulting from delayed presentation. More recent reports suggest that CPH can present with nodules, lymphadenopathy, or infiltrates, with cavities being a less common feature. Emphysema is the main risk factor for cavitary CPH. CPH is therefore an umbrella term, with chronic cavitary pulmonary histoplasmosis and Histoplasma nodules being the main long-term manifestations in nonimmunocompromised individuals. Diagnosis relies on a high index of suspicion, use of fungal culture of respiratory samples, antibody testing, and compatible radiological picture. Treatment with itraconazole for at least 12 months is recommended. Morbidity from CPH results from slow progression of cavities and gradual loss of lung function, especially if not recognized and treated. Studies on the epidemiology of CPH are needed in order to improve understanding of the disease.

Predictors of time to unfavorable treatment outcomes among patients with multidrug resistant tuberculosis in Oromia region, Ethiopia

Background

Multidrug-resistant tuberculosis (MDR-TB) is a man-made problem when bacteria are resistant to at least two anti TB drugs (Rifampicin and Isoniazid). Currently from tuberculosis infected patients, two out of ten are developing MDR-TB and it is an emerging public health problem in Ethiopia. Despite high burden of MDR-TB in Ethiopia, the treatment outcomes and predictors related to incidence among MDR-TB patients is not studied in Oromia region, Ethiopia. Therefore, the present study assessed the predictors of time to unfavorable treatment outcomes among patients with multidrug resistant tuberculosis in Oromia region, Ethiopia

Method

Facility based retrospective cohort study was conducted at hospitals in Oromia Region. All registered MDR-TB patient charts from 2015 to 2017 were considered for the study. Data entry was done by using EPI data version 3.1 Statistical Software and data analysis was done by SPSS version 20. The descriptive statistics, frequency, median and range were employed. Bivariate and multivariate Cox proportional hazard regression analysis was used to identify predictors of time to unfavorable treatment outcomes of multidrug resistant tuberculosis. In multivariate Cox proportional hazard regression analysis, the variables with P- value less than and equal to 0.05 were considered as predictor variables for time to unfavorable treatment outcome of MDR-TB.

Result

From the total of 415 (92.84%) complete MDR-TB charts, the overall cumulative probability of unfavorable treatment outcome at the end of the treatment (two years) was 21.21%. In multivariate Cox proportional hazard analysis initial culture result [AHR = 0.52; 95% CI: 0.29, 0.96], HIV test result [AHR = 3.76; 95% CI: 2.45, 5.78] and culture at the end of continuation phases [AHR = 0.12; 95% CI: 0.08, 0.20] were the predictors of unfavorable treatment outcome.

Conclusion

The magnitude of unfavorable treatment outcome at Oromia hospitals was lower than WHO regional report of 2018. This finding demonstrated that low unfavorable treatment outcomes for MDR-TB patients can be achieved in a resource-constrained and high TB-burden setting. Whereas, Initial culture result, HIV test result and culture at the end of continuation phases were determined as predictor factors with associated unfavorable treatment outcomes. Culture positive and HIV positive MDR-TB patients need special attention at the time of treatment.

Surveillance of drug resistance tuberculosis based on reference laboratory data in Ethiopia

Background

Both passive and active surveillance of drug resistance have an important role in tuberculosis (TB) control program. Surveillance data are important to estimate the magnitude of drug resistance TB, to know the trend of the disease, assess the performance of the program, and to forecast diagnosis and treatment supplies. Therefore, this study aimed to determine the prevalence and the proportion of drug resistant tuberculosis in Ethiopia based on passively collected data.

Methods

A cross-sectional study was conducted at the National Tuberculosis Reference Laboratory and seven Regional TB laboratories in Ethiopia on a retrospective data collected from July 2017 to June, 2018. Data were collected by standardized checklist from TB culture laboratory registration book. Percentage of recovery rate, contamination rate, and prevalence of drug resistance TB were determined by Statistical Package for Social Science (SPSS) version 23.

Result

Of 10 134 TB suspected individuals included into this analysis, 1183 (11.7%) were culture positive. The overall contamination proportion was 5.3% and nontuberculous mycobacteria proportion was 0.98%. First-line drug susceptibility test was performed for 329 Mycobacterium tuberculosis complex isolates, and the proportion of resistance was 5.7 and 6.3% for isoniazid and rifampicin respectively. The proportion of multidrug-resistant tuberculosis (MDR-TB) was 4.3% in new patients, while 6.7% in previously treated patients. However, there was no category for 0.6% patients, and the overall proportion of MDR-TB was 11.6%.

Conclusions

The result of this study indicated that MDR-TB is a serious public health problem in Ethiopia. Thus, strengthen prevention and control program is vital to halt the burden of drug resistant TB in the country.

Electronic supplementary material

The online version of this article (10.1186/s40249-019-0554-4) contains supplementary material, which is available to authorized users.

Strategies towards the synthesis of anti-tuberculosis drugs

In this report, we reviewed the strategies towards the synthesis of anti-tuberculosis drugs. They include semisynthetic approaches, resolution based strategies, microbial transformations, solid phase synthesis, and asymmetric synthesis.

Epidemiology of multidrug-resistant tuberculosis (MDR-TB) in Ethiopia: a systematic review and meta-analysis of the prevalence, determinants and treatment outcome

INTRODUCTION

The emergence of MDR-TB remained a major public health threat particularly in developing countries. With increased prevalence and complexity of treatment, the burden of MDR-TB challenged the country. It is of an important; the epidemiology of drug resistant TB is not well understood. There are few studies conducted to assess the prevalence, determinants and treatment outcome of MDR-TB with inconclusive finding. Therefore, we aimed to conduct a systematic review and meta-analysis on Epidemiology of MDR-TB in Ethiopia, So that policy makers and other stalk holders could have pooled evidence on the problem to make a decision.

METHODS

The review was conducted through a systematic literature search of articles published between 1997 and 2017. Five bibliographic databases and libraries: PubMed/Medline, Global Health Database, Embase, the Cochrane Library, and African Index Medicus were used. After cleaning and sorting, analysis was performed using STATA version 11. The pooled rate of MDR-TB prevalence, determinants and treatment outcome was estimated with a random-effects model. Heterogeneity was assessed by the I2 and publication bias through funnel plot.

RESULTS

The 34 studies that were retained for final analysis enrolled a total of 7461 TB or MDR-TB patients. We found that 2.18% (95% CI 1.44-2.92%) of newly diagnosed and 21.07% (95% CI 11.47-30.67%) of previously treated patients have MDR-TB with overall prevalence of 7.24% (95% CI 6.11-8.37). History of previous treatment is the major determinant (pooled OR = 4.78 (95% CI 3.16-6.39)), while contact history and adherence also contributed. In this review the pooled death computed among 5 articles showed that 12.25% (95% CI 9.39-15.11%) of MDR-TB patients were died in the course of treatment. Complication, drug side effects and HIV infection were the main determinants for the death.

CONCLUSION AND RECOMMENDATION

The prevalence is by far higher than the previous reports. It is mainly associated with history of previous treatment along with contact history. However, the treatment outcomes are comparable with previous studies, yet it is a concern. Comorbidities, drug side effects and HIV sero-positivity were the determinants. Thus, proper treatment of drug susceptible TB and early detection and treatment of MDR-TB before complication develops along with prevention of drug side effect and contacts with MDR-TB cases are very important.

Drug-resistance patterns of Mycobacterium tuberculosis strains and associated risk factors among multi drug-resistant tuberculosis suspected patients from Ethiopia

BACKGROUND

Multidrug drug-resistant tuberculosis (MDR-TB) is a major health problem and seriously threatens TB control and prevention efforts globally. Ethiopia is among the 30th highest TB burden countries for MDR-TB with 14% prevalence among previously treated cases. The focus of this study was on determining drug resistance patterns of Mycobacterium tuberculosis among MDR-TB suspected cases and associated risk factors.

METHODS

A cross-sectional study was conducted in Addis Ababa from June 2015 to December 2016. Sputum samples and socio-demographic data were collected from 358 MDR-TB suspected cases. Samples were analyzed using Ziehl-Neelsen technique, GeneXpert MTB/RIF assay, and culture using Lowenstein-Jensen and Mycobacterial growth indicator tube. Data were analyzed using SPSS version 23.

RESULTS

A total of 226 the study participants were culture positive for Mycobacterium tuberculosis, among them, 133 (58.8%) participants were males. Moreover, 162 (71.7%) had been previously treated for tuberculosis, while 128 (56.6%) were TB/HIV co-infected. A majority [122 (54%)] of the isolates were resistant to any first-line anti-TB drugs. Among the resistant isolates, 110 (48.7%) were determined to be resistant to isoniazid, 94 (41.6%) to streptomycin, 89 (39.4%) to rifampicin, 72 (31.9%) to ethambutol, and 70 (30.9%) to pyrazinamide. The prevalence of MDR-TB was 89 (39.4%), of which 52/89 (58.4%) isolates were resistance to all five first-line drugs. Risk factors such as TB/HIV co-infection (AOR = 5.59, p = 0.00), cigarette smoking (AOR = 3.52, p = 0.045), alcohol drinking (AOR = 5.14, p = 0.001) hospital admission (AOR = 3.49, p = 0.005) and visiting (AOR = 3.34, p = 0.044) were significantly associated with MDR-TB.

CONCLUSIONS

The prevalence of MDR-TB in the study population was of a significantly high level among previously treated patients and age group of 25-34. TB/HIV coinfection, smoking of cigarette, alcohol drinking, hospital admission and health facility visiting were identified as risk factors for developing MDR-TB. Therefore, effective strategies should be designed considering the identified risk factors for control of MDR-TB.

Risk factors associated with multidrug-resistant tuberculosis (MDR-TB) in a tertiary armed force referral and teaching hospital, Ethiopia

Background

Ethiopia is one of the world health organization defined higher tuberculosis (TB) burden countries where the disease remains a massive public health threat. This study aimed to identify the prevalence and associated factors of multidrug-resistant tuberculosis (MDR-TB) using all armed force and civilian TB attendants in a tertiary level armed force hospital, where data for MDR-TB are previously unpublished.

Methods

Cross-sectional study was conducted from September 2014 to August 2015 in a tertiary level Armed Force Referral and Teaching Hospital (AFRTH), Ethiopia. Armed force members (n = 251) and civilians (n = 130) which has been undergone TB diagnosis at AFRTH were included. All the specimens collected were subjected to microscopic smear observation, culture growth and drug susceptibility testing. Data were analyzed using statistical package for social sciences following binary logistic regression and Chi-square. P-values < 0.05 were considered statistically significant.

Results

Among 381 TB patients, 355 (93.2%) new and 26 (6.8%) retreatment cases were identified. Culture and smear positive TB cases were identified in 297 (77.9%) and 252 (66.1%) patients, respectively. The overall prevalence of MDR-TB in AFRTH was found 1.8% (1.3% for armed force members and 0.5% for civilian patients) all of which were previously TB treated cases. The entire treatment success rates were 92.6% achieved highest in the armed force (active and pension) than the civilian patients. The failure and dead cases were also found 2.5 and 4.6%, respectively. Using bivariate analysis, category of attendants and TB contact history were strong predictors of MDR-TB in armed force and civilian patients. Moreover, human immunodeficiency virus (HIV) infection also identified a significant (OR = 14.6; 95% CI = 2.3–92.1; p = 0.004) predicting factor for MDR-TB in armed force members. However, sex, age and body mass index were not associated factor for MDR-TB.

Conclusions

In AFRTH, lower prevalence of MDR-TB was identified in armed force and civilian patients that were significantly associated with category of attendants, HIV infection and TB contact history. Considering armed force society as one segment of population significantly helps to plan a better MDR-TB control management, especially for countries classified as TB high burden country.

Trends in prevalence of multi drug resistant tuberculosis in sub-Saharan Africa: A systematic review and meta-analysis

Background

Multidrug resistant tuberculosis (MDR-TB), is an emerging public health problem in sub-Saharan Africa (SSA). This study aims to determine the trends in prevalence of MDR-TB among new TB cases in sub-Saharan Africa over two decades.

Methods

We searched electronic data bases and accessed all prevalence studies of MDR-TB within SSA between 2007 and 2017. We determined pooled prevalence estimates using random effects models and determined trends using meta-regression.

Results

Results: We identified 915 studies satisfying inclusion criteria. Cumulatively, studies reported on MDR-TB culture of 34,652 persons. The pooled prevalence of MDR-TB in new cases was 2.1% (95% CI; 1.7–2.5%). There was a non-significant decline in prevalence by 0.12% per year.

Conclusion

We found a low prevalence estimate of MDR-TB, and a slight temporal decline over the study period. There is a need for continuous MDR-TB surveillance among patients with TB.

Role of Interferons in the Development of Diagnostics, Vaccines, and Therapy for Tuberculosis

Tuberculosis (TB) is an airborne infection caused by Mycobacterium tuberculosis (Mtb). About one-third of the world's population is latently infected with TB and 5–15% of them will develop active TB in their lifetime. It is estimated that each case of active TB may cause 10–20 new infections. Host immune response to Mtb is influenced by interferon- (IFN-) signaling pathways, particularly by type I and type II interferons (IFNs). The latter that consists of IFN-γ has been associated with the promotion of Th1 immune response which is associated with protection against TB. Although this aspect remains controversial at present due to the lack of established correlates of protection, currently, there are different prophylactic, diagnostic, and immunotherapeutic approaches in which IFNs play an important role. This review summarizes the main aspects related with the biology of IFNs, mainly associated with TB, as well as presents the main applications of these cytokines related to prophylaxis, diagnosis, and immunotherapy of TB.

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.

Ribosomal mutations promote the evolution of antibiotic resistance in a multidrug environment

Antibiotic resistance arising via chromosomal mutations is typically specific to a particular antibiotic or class of antibiotics. We have identified mutations in genes encoding ribosomal components in Mycobacterium smegmatis that confer resistance to several structurally and mechanistically unrelated classes of antibiotics and enhance survival following heat shock and membrane stress. These mutations affect ribosome assembly and cause large-scale transcriptomic and proteomic changes, including the downregulation of the catalase KatG, an activating enzyme required for isoniazid sensitivity, and upregulation of WhiB7, a transcription factor involved in innate antibiotic resistance. Importantly, while these ribosomal mutations have a fitness cost in antibiotic-free medium, in a multidrug environment they promote the evolution of high-level, target-based resistance. Further, suppressor mutations can then be easily acquired to restore wild-type growth. Thus, ribosomal mutations can serve as stepping-stones in an evolutionary path leading to the emergence of high-level, multidrug resistance.

DOI:http://dx.doi.org/10.7554/eLife.20420.001

The rise of antibiotic resistant bacteria is challenging clinicians, and some infections are now resistant to almost all of the drugs that are currently available. Some types of bacteria – such as mycobacteria, which include the bacteria that cause tuberculosis and leprosy – can only acquire antibiotic resistance from mutations that alter their existing genes. The process by which bacteria develop resistance to multiple drugs is generally viewed as a stepwise accumulation of different mutations. However, the role of individual mutations that increase a bacterium’s resistance to multiple antibiotics has not been fully explored.

Gomez, Kaufmann-Malaga et al. exposed bacteria from the species Mycobacterium smegmatis, a cousin of the bacterium that causes tuberculosis, to a mixture of relatively low concentrations of different antibiotics that should kill the bacteria relatively slowly. Hundreds of small bacteria cultures were grown in parallel, and only a fraction of them developed antibiotic-resistant members. Gomez, Kaufmann-Malaga et al. identified mutations in these bacteria that unexpectedly gave the bacteria resistance to several unrelated classes of antibiotics.

Individual mutants carried single mutations in different components of the ribosome, a complex molecular machine that helps to build proteins inside cells. As well as increasing their resistance to antibiotics, these mutations also reduced the growth rate of the bacteria. This meant that when the bacteria were grown in an antibiotic-free environment they survived less well than non-mutant bacteria. However, the mutations gave the bacteria an advantage in environments that contained many different antibiotics, as they could more easily develop mutations that made them more resistant to other drugs. Thus, the mutant bacteria can serve as stepping-stones toward the development of high-level resistance to multiple drugs.

Further work will now explore whether this phenomenon occurs in a range of other bacterial species, including the bacteria that cause tuberculosis. While new antibiotics are desperately needed, a better understanding of how bacteria evolve the ability to resist the effects of antibiotics will help us to preserve the usefulness of existing and future drugs.

DOI:http://dx.doi.org/10.7554/eLife.20420.002

Crystal structures of the CO and NOBound DosS GAF-A domain and implications for DosS signaling in Mycobacterium tuberculosis

DosS is a sensor in Mycobacterium tuberculosis that differentially responds to O₂, NO, and CO, as well as to changes in the redox state of the prosthetic heme iron atom. The ferrous protein and its Fe(II)NO and Fe(II)CO complexes undergo autophosphorylation and subsequently transfer the phosphate group to DosR, a nuclear factor, to activate it. In contrast, autophosphorylation is negligible with the ferric protein and the Fe(II)O₂ complex. To clarify the basis for this differential response to gases, we have determined the crystal structures of the NO and COcomplexes of the DosS GAF-A domain, which contains the heme to which the gases bind. Comparison of these crystal structures with those reported for the phosphorylation-inactive ferric GAF-A domain suggest that the GAF-A domain is in a dynamic equilibrium between active and inactive states, and that the position of Glu87 in the heme cavity, which depends on the which gas is bound, acts as a modulator of the equilibrium, and therefore of catalytic activity.

Prevalence of Drug Resistance Mycobacterium Tuberculosis among Patients Seen in Coast Provincial General Hospital, Mombasa, Kenya

Background

Although prevention and control of spread of multi-drug resistant tuberculosis strains is a global challenge, there is paucity of data on the prevalence of DR-TB in patients diagnosed with TB in referral hospitals in Kenya. The present study assessed patients’ characteristics and prevalence of drug resistant TB in sputa smear positive TB patients presenting to Coast Provincial General Hospital (CPGH) in Mombasa, Kenya.

Methods

Drug resistance was evaluated in 258 randomly selected sputa smear TB positive cases between the periods of November 2011 to February 2012 at the CPGH-Mombasa. Basic demographic data was obtained using administered questionnaires, and clinical history extracted from the files. For laboratory analyses, 2mls of sputum was obtained, decontaminated and subjected to mycobacteria DNA analyses. Detection of first line drug resistance genes was done using MDRTDR plus kit. This was followed with random selection of 83 cases for second line drug resistance genes testing using Genotype MDRTBsl probe assay kit (HAINS Lifesciences, GmbH, Germany), in which ethambutol mutation probes were included. The data was then analyzed using SPSS statistical package version 19.0.

Results

Male to female ratio was 1:2. Age range was 9 to 75 years, with median of 30 years. New treatment cases constituted 253(98%), among which seven turned out to be PTB negative, and further grouped as 4 (1.6%) PTB negative and 3(1.1%) NTM. 237(91.7%) new cases were fully susceptible to INH and RIF. The remaining, 8 (3.1%) and 1(0.4%) had mono- resistance to INH and RIF, respectively. All the retreatment cases were fully susceptible to the first line drugs. HIV positivity was found in 48 (18.6%) cases, of which 46(17.8%) were co-infected with TB. Of these, 44 (17.1%) showed full susceptibility to TB drugs, while 2 (0.8%) were INH resistant. For the second line drugs, one case each showed mono resistance to both and FQ. Also, one case each showed drug cross poly resistance to both ETH and FQ, with second line injectable antibiotics. However, no significant statistical correlation was established between TB and resistance to the second line drugs p = 0.855.

Conclusion

The findings of this study showed the existence of resistance to both first and second line anti-tubercular drugs, but no MDR-TB and XDR-TB was detected among patients attending TB clinic at CPGH using molecular techniques.

Multidrug resistant tuberculosis: prevalence and risk factors in districts of metema and west armachiho, Northwest Ethiopia

BACKGROUND

Multi drug resistant tuberculosis (MDR-TB) is an emerging challenge for TB control programs globally. According to World health organization, 2012 report Ethiopia stands 15(th) out of the 27 high priority countries in the world and 3(rd) in Africa. Updated knowledge of the magnitude of MDR-TB is so substantial to allocate resources, and to address prevention and control measures. Therefore, the aim of this study was to assess the prevalence of MDR-TB and associated risk factors in West Armachiho and Metema districts of North Gondar.

METHODS

A cross-sectional study was conducted in West Armachiho and Metema districts between February 01 and June 25, 2014. A total of 124 consecutive smear positive pulmonary tuberculosis patients were included in the study. Socio-demographic and possible risk factor data were collected using a semi-structured questionnaire. Drug susceptibility testing was first performed for rifampicin using GeneXpert MTB/RIF. For those rifampicin resistant strains, drug susceptibility testing was performed for both isoniazid and rifampicin to identify MDR-TB using the proportional method on LJ media. Data were analyzed using statistical Package SPSS version 20; binary logistic regression was used to assess the association. P-values < 0.05 were considered as statistically significant.

RESULTS

Of 124 smear-positive pulmonary TB patients, 117 (94.4 %) were susceptible to Rifampicin, while 7 (5.7 %) were confirmed to be resistant to Rifampicin and Isoniazid. The overall prevalence of MDR-TB was 5.7 % (2.3 % among new cases and 13.9 % among previously treated cases). History of previous treatment (OR = 7, P = 0.025) was significantly associated risk factor for MDR-TB.

CONCLUSION

The overall prevalence of MDR-TB was 5.7 % among cases at five health centers and a history of previous treatment was found to be a risk factor for being infected by an MDR-TB strain. Therefore, maximizing early case detection and treatment, strengthening TB infection control activities and proper implementation of DOTS are recommended to reduce the burden of MDR-TB.

Drug resistance patterns of Mycobacterium tuberculosis complex and associated factors among retreatment cases around Jimma, Southwest Ethiopia

Background

Information on the pattern of drug resistant tuberculosis (TB) among re-treatment cases is crucial to develop appropriate control strategies. Therefore, we conducted this study to assess the drug resistance pattern of M. tuberculosis complex (MTBC) isolates and associated factors among re-treatment cases in Jimma area, Southwest Ethiopia.

Methods

Health facility-based cross-sectional study was conducted between March 2012 and April 2013 in Jimma area, Southwest Ethiopia. We included 79 re-treatment cases selected conveniently. Socio demographic and clinical data were collected using structured questionnaire. Sputum sample processing, mycobacterial culture, isolation and drug susceptibility testing (DST) were done at Mycobacteriology Research Centre (MRC) of Jimma University. All data were registered and entered in to SPSS version 20. Crude odds ratio (COR) and adjusted odds ratios (AOR) were calculated. P-values less than 0.05 were considered statistically significant.

Results

Seventy-nine re-treatment cases included in the study; 48 (60.8 %) were males. Forty- seven (59.5 %) study participants were from rural area with the mean age of 31.67 ± 10.02 SD. DST results were available for 70 MTBC isolates. Majority (58.6 % (41/70)) isolates were resistant to at least one of the four first line drugs. The prevalence of multidrug-resistant TB (MDR-TB) was 31.4 % (22/70). Place of residence (AOR = 3.44 (95 % CI: 1.12, 10.60), duration of illness (AOR = 3.00 (95 % CI: 1.17, 10.69) and frequency of prior TB therapy (AOR = 2.99, (95 % CI: 1.01, 8.86) were significant factors for any drug resistance. Moreover, history of treatment failure was found to be associated with MDR-TB (AOR = 3.43 (95 % CI: 1.14, 10.28).

Conclusion

The overall prevalence of MDR-TB among re-treatment cases around Jimma was high. The rate of MDR-TB was higher in patients with the history of anti-TB treatment failure. Timely identification and referral of patients with the history of treatment failure for culture and DST need to be strengthened.

Multidrug-resistant tuberculosis in Ethiopia: efforts to expand diagnostic services, treatment and care

The emergence of drug-resistant tuberculosis (TB), particularly multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB, is a major public health problem. The purpose of this review is to describe the current status of MDR-TB and factors that increase the risk of this infection. We conducted a systematic review of the literature on MDR-TB in Ethiopia. Out of 766 articles, 23 were found to meet eligibility criteria and included in this review. Among the 23 papers, six of them reported high prevalence of MDR-TB in the range of 3.3%-46.3%. Likewise, two studies reported XDR-TB in the range of 1% - 4.4% in Ethiopia. The most powerful predictor of the emergence of MDR-TB reported in Ethiopia is previous exposure to anti-TB drug treatment. This review indicated that MDR-TB in Ethiopia is a serious public health problem that needs to be addressed urgently. Strengthening early case detection and proper treatment of drug-susceptible TB in accordance with World Health Organization (WHO) treatment guidelines to ensure adequate treatment success rates is critical. Consequently, efforts have been made to a rapidly increase MDR-TB diagnosis as well as the number of treatment sites to implement a directly observed treatment, short-course (DOTS) plus strategy to interrupt transmission of MDR-TB.

Global control of tuberculosis: from extensively drug-resistant to untreatable tuberculosis

Extensively drug-resistant tuberculosis is a burgeoning global health crisis mainly affecting economically active young adults, and has high mortality irrespective of HIV status. In some countries such as South Africa, drug-resistant tuberculosis represents less than 3% of all cases but consumes more than a third of the total national budget for tuberculosis, which is unsustainable and threatens to destabilise national tuberculosis programmes. However, concern about drug-resistant tuberculosis has been eclipsed by that of totally and extremely drug-resistant tuberculosis--ie, resistance to all or nearly all conventional first-line and second-line antituberculosis drugs. In this Review, we discuss the epidemiology, pathogenesis, diagnosis, management, implications for health-care workers, and ethical and medicolegal aspects of extensively drug-resistant tuberculosis and other resistant strains. Finally, we discuss the emerging problem of functionally untreatable tuberculosis, and the issues and challenges that it poses to public health and clinical practice. The emergence and growth of highly resistant strains of tuberculosis make the development of new drugs and rapid diagnostics for tuberculosis--and increased funding to strengthen global control efforts, research, and advocacy--even more pressing.

Community-acquired pneumonia and tuberculosis: differential diagnosis and the use of fluoroquinolones

The respiratory fluoroquinolones moxifloxacin, gemifloxacin, and high-dose levofloxacin are recommended in guidelines for effective empirical antimicrobial therapy of community-acquired pneumonia (CAP). The use of these antibiotics for this indication in areas with a high prevalence of tuberculosis (TB) has been questioned due to the perception that they contribute both to delays in the diagnosis of pulmonary TB and to the emergence of fluoroquinolone-resistant strains of Mycobacterium tuberculosis. In this review, we consider some of the important questions regarding the potential use of fluoroquinolones for the treatment of CAP where the burden of TB is high. The evidence suggests that the use of fluoroquinolones as recommended for 5-10 days as empirical treatment for CAP, according to current clinical management guidelines, is appropriate even in TB-endemic regions. It is critical to quickly exclude M. tuberculosis as a cause of CAP using the most rapid relevant diagnostic investigations in the management of all patients with CAP.

Co(II) and Cu(II) pyrophosphate complexes have selectivity and potency against Mycobacteria including Mycobacterium tuberculosis

Tuberculosis (TB) causes up to 10 million incident cases worldwide per annum. Multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains are leading factors in the resurgence of TB cases and the need to produce new agents to combat such infection. Herein, we describe Co(II) and Cu(II) metal based complexes that feature the pyrophosphate ligand with notable selectivity and marked potency against Mycobacterium tuberculosis, including MDR strains. Such complexes are confirmed to be bacteriocidal and not affected by efflux inhibitors. Finally, while susceptibility to copper has recently been established for M. tuberculosis, the greater efficacy of cobalt observed herein is of considerable note and in line with the discovery of a copper metallothionein in M. tuberculosis.

Drug-resistant tuberculosis: pediatric guidelines

The World Health Organization estimates that there are 650,000 prevalent cases of multidrug-resistant (MDR) tuberculosis (TB) globally, and since children (<15 years of age) constitute up to 20 % of the TB caseload in high-burden settings, the number of children with drug-resistant (DR) TB is likely to be substantial. Because bacterial burden at the site of disease is often low, diagnosis involves collection of multiple specimens and a laboratory capable of performing culture, although the Xpert MTB/RIF assay has improved sensitivity over smear examination. The basic principles of treatment for children are the same as those for adults with MDR-TB; however, the treatment regimen is often empiric and based on the drug susceptibility pattern of the source case, if available, or on past history of treatment. Additional challenges arise when MDR-TB is diagnosed and managed in the context of HIV coinfection. HIV-infected children are also treated with antiretroviral therapy medications, which have the potential to interact with second-line anti-TB drugs. Lack of pediatric formulations of second-line drugs and paucity of pharmacokinetic data make dosage challenging. However, when treated appropriately, children with DR TB have good outcomes.

Characteristics of multidrug-resistant tuberculosis in Namibia

Background

To describe the epidemiology and possible risk factors for the development of multidrug-resistant tuberculosis (MDR-TB) in Namibia.

Methods

Using medical records and patient questionnaires, we conducted a case-control study among patients diagnosed with TB between January 2007 and March 2009. Cases were defined as patients with laboratory-confirmed MDR-TB; controls had laboratory-confirmed drug-susceptible TB or were being treated with WHO Category I or Category II treatment regimens.

Results

We enrolled 117 MDR-TB cases and 251 TB controls, of which 100% and 2% were laboratory-confirmed, respectively. Among cases, 97% (113/117) had been treated for TB before the current episode compared with 46% (115/251) of controls (odds ratio [OR] 28.7, 95% confidence interval [CI] 10.3–80.5). Cases were significantly more likely to have been previously hospitalized (OR 1.9, 95% CI 1.1–3.5) and to have had a household member with MDR-TB (OR 5.1, 95% CI 2.1–12.5). These associations remained significant when separately controlled for being currently hospitalized or HIV-infection.

Conclusions

MDR-TB was associated with previous treatment for TB, previous hospitalization, and having had a household member with MDR-TB, suggesting that TB control practices have been inadequate. Strengthening basic TB control practices, including expanding laboratory confirmation, directly observed therapy, and infection control, are critical to the prevention of MDR-TB.

Underestimation of the resistance of Mycobacterium tuberculosis to second-line drugs by the new GenoType MTBDRsl test

The GenoType MTBDRsl is a new-generation PCR-based line-probe assay for the detection of extensively drug-resistant tuberculosis (XDR-TB). This study evaluated the performance of MTBDRsl in detecting genotypic resistance to ethambutol, kanamycin, and ofloxacin in Mycobacterium tuberculosis (MTB) strains. The drug resistance of 262 unique clinical MTB isolates from China was analyzed with MTBDRsl, traditional TB drug susceptibility testing (DST), and sequencing. Sensitivity of MTBDRsl was 62.4% (93/149; 95% CI = 54.1 to 70.2) for detection of ethambutol resistance, 57.9% (55/95; 95% CI = 47.3 to 68) for kanamycin resistance, and 81% (111/137; 95% CI = 73.4 to 87.2) for ofloxacin resistance; specificity was 76.8% (86/112; 95% CI = 67.9 to 84.2), 98.8% (164/166; 95% CI = 95.7 to 99.9), and 91.1% (113/124; 95% CI = 84.7 to 95.5), respectively. Sequencing suggested that 36.9% (55/149) of ethambutol-resistant strains had no embB306 mutation and that 26.8% (40/149) had embB497 mutation not covered by MTBDRsl. Furthermore, MTBDRsl indicated ethambutol resistance in 23.2% (26/112) of ethambutol-susceptible strains, of which 92.3% (24/26) were confirmed resistant by sequencing. This study demonstrated that genotypic resistance to ethambutol, kanamycin, and ofloxacin in MTB can be quickly determined with the MTBDRsl. As a rapid and convenient genetic method, this assay could function as a supplement to traditional DST. More relevant genetic markers are needed to improve sensitivity.

Evaluation of the burden of unsuspected pulmonary tuberculosis and co-morbidity with non-communicable diseases in sputum producing adult inpatients

BACKGROUND

A high burden of tuberculosis (TB) occurs in sub-Saharan African countries and many cases of active TB and drug-resistant TB remain undiagnosed. Tertiary care hospitals provide an opportunity to study TB co-morbidity with non-communicable and other communicable diseases (NCDs/CDs). We evaluated the burden of undiagnosed pulmonary TB and multi-drug resistant TB in adult inpatients, regardless of their primary admission diagnosis, in a tertiary referral centre.

METHODOLOGY/PRINCIPAL FINDINGS

In this prospective study, newly admitted adult inpatients able to produce sputum at the University Teaching Hospital, Lusaka, Zambia, were screened for pulmonary TB using fluorescent smear microscopy and automated liquid culture. The burden of pulmonary TB, unsuspected TB, TB co-morbidity with NCDs and CDs was determined. Sputum was analysed from 900 inpatients (70.6% HIV infected) 277 (30.8%) non-TB suspects, 286 (31.8%) TB suspects and 337 (37.4%) were already receiving TB treatment. 202/900 (22.4%) of patients had culture confirmed TB. TB co-morbidity was detected in 20/275 (7.3%) NCD patients, significantly associated with diabetes (P = 0.006, OR 6.571, 95%CI: 1.706-25.3). 27/202 (13.4%) TB cases were unsuspected. There were 18 confirmed cases of MDR-TB, 5 of which were unsuspected.

CONCLUSIONS/SIGNIFICANCE

A large burden of unsuspected pulmonary TB co-morbidity exists in inpatients with NCDs and other CDs. Pro-active sputum screening of all inpatients in tertiary referral centres in high TB endemic countries is recommended. The scale of the problem of undiagnosed MDR-TB in inpatients requires further study.

Evaluation of the Xpert MTB/RIF assay at a tertiary care referral hospital in a setting where tuberculosis and HIV infection are highly endemic

BACKGROUND. There were 1.45 million deaths from tuberculosis in 2011. A substantial proportion of active pulmonary tuberculosis cases in countries where tuberculosis, human immunodeficiency virus (HIV) infection, and AIDS are highly endemic remain undiagnosed because of the reliance on sputum-smear microscopy. This study evaluated the performance of the Xpert MTB/RIF assay at a tertiary care referral center in Zambia, a country where the burden of tuberculosis and HIV infection is high. METHODS. A total of 881 adult inpatients admitted to University Teaching Hospital in Lusaka who were able to produce sputum were enrolled and analyzed in the study, irrespective of admission diagnosis. Sputum specimens were analyzed by fluorescence smear microscopy, the Xpert MTB/RIF assay, mycobacterial growth indicator tube (MGIT) culture,and MGIT drug-susceptibility testing. The sensitivity and specificity of the Xpert MTB/RIF assay were evaluated using culture as the gold standard. RESULTS. Culture-confirmed tuberculosis was found in 201 of 881 patients (22.8%). The specificity of the Xpert MTB/RIF assay was 95.0% (95% confidence interval [CI], 92.4%–96.8%),and the sensitivity was 86.1% (95% CI, 80.3%–90.4%). In sputum smear–negative, culture-positive cases, the assay was 74.7% sensitive (95% CI, 64.6%–82.8%), identifying 71 additional tuberculosis cases that were not detected by smear microscopy.A total of 18 of 111 patients with tuberculosis who were tested (16.2%) had multidrug-resistant (MDR) tuberculosis.The sensitivity and specificity of the Xpert MTB/RIF assay for detecting culture-confirmed, rifampicin-resistant tuberculosis was 81.3% (95% CI, 53.7%–95.0%) and 97.5% (95% CI,90.4%–99.6%), respectively. CONCLUSIONS. The Xpert MTB/RIF assay performs better than smear microscopy in an inpatient setting in a country where tuberculosis and HIV infection are highly endemic. Assessment of its usefulness and cost-effectiveness for increased detection of tuberculosis cases missed by sputum smear and for concomitant screening for MDR tuberculosis among adult inpatients attending tertiary care referral centers in other countries with a high burden of tuberculosis and HIV infection is warranted [corrected].