Nosocomial transmission of extensively drug-resistant tuberculosis in a rural hospital in South Africa

Accuracy of digital chest x-ray analysis with artificial intelligence software as a triage and screening tool in hospitalized patients being evaluated for tuberculosis in Lima, Peru

Introduction

Tuberculosis (TB) transmission in healthcare facilities is common in high-incidence countries. Yet, the optimal approach for identifying inpatients who may have TB is unclear. We evaluated the diagnostic accuracy of qXR (Qure.ai, India) computer-aided detection (CAD) software versions 3.0 and 4.0 (v3 and v4) as a triage and screening tool within the FAST (Find cases Actively, Separate safely, and Treat effectively) transmission control strategy.

Methods

We prospectively enrolled two cohorts of patients admitted to a tertiary hospital in Lima, Peru: one group had cough or TB risk factors (triage) and the other did not report cough or TB risk factors (screening). We evaluated the sensitivity and specificity of qXR for the diagnosis of pulmonary TB using culture and Xpert as primary and secondary reference standards, including stratified analyses based on risk factors.

Results

In the triage cohort (n=387), qXR v4 sensitivity was 0.91 (59/65, 95% CI 0.81-0.97) and specificity was 0.32 (103/322, 95% CI 0.27-0.37) using culture as reference standard. There was no difference in the area under the receiver-operating-characteristic curve (AUC) between qXR v3 and qXR v4 with either a culture or Xpert reference standard. In the screening cohort (n=191), only one patient had a positive Xpert result, but specificity in this cohort was high (>90%). A high prevalence of radiographic lung abnormalities, most notably opacities (81%), consolidation (62%), or nodules (58%), was detected by qXR on digital CXR images from the triage cohort.

Conclusions

qXR had high sensitivity but low specificity as a triage in hospitalized patients with cough or TB risk factors. Screening patients without cough or risk factors in this setting had a low diagnostic yield. These findings further support the need for population and setting-specific thresholds for CAD programs.

Implementing Innovative Approaches to Improve Health Care Delivery Systems for Integrating Communicable and Non-Communicable Diseases Using Tuberculosis and Diabetes as a Model in Tanzania

Background: Many evidence-based health interventions, particularly in low-income settings, have failed to deliver the expected impact. We designed an Adaptive Diseases Control Expert Programme in Tanzania (ADEPT) to address systemic challenges in health care delivery and examined the feasibility, acceptability and effectiveness of the model using tuberculosis (TB) and diabetes mellitus (DM) as a prototype. Methods: This was an effectiveness-implementation hybrid type-3 design that was implemented in Dar es Salaam, Iringa and Kilimanjaro regions. The strategy included a stepwise training approach with web-based platforms adapting the Gibbs' reflective cycle. Health facilities with TB services were supplemented with DM diagnostics, including glycated haemoglobin A1c (HbA1c). The clinical audit was deployed as a measure of fidelity. Retrospective and cross-sectional designs were used to assess the fidelity, acceptability and feasibility of the model. Results: From 2019-2021, the clinical audit showed that ADEPT intervention health facilities more often identified median 8 (IQR 6-19) individuals with dual TB and DM, compared with control health facilities, median of 1 (IQR 0-3) (p = 0.02). Likewise, the clinical utility of HbA1c on intervention sites was 63% (IQR:35-75%) in TB/DM individuals compared to none in the control sites at all levels, whereas other components of the standard of clinical management of patients with dual TB and DM did not significantly differ. The health facilities showed no difference in screening for additional comorbidities such as hypertension and malnutrition. The stepwise training enrolled a total of 46 nurse officers and medical doctors/specialists for web-based training and 40 (87%) attended the workshop. Thirty-one (67%), 18 nurse officers and 13 medical doctors/specialists, implemented the second step of training others and yielded a total of 519 additional front-line health care workers trained: 371 nurses and 148 clinicians. Overall, the ADEPT model was scored as feasible by metrics applied to both front-line health care providers and health facilities. Conclusions: It was feasible to use a stepwise training and clinical audit to support the integration of TB and DM management and it was largely acceptable and effective in differing regions within Tanzania. When adapted in the Tanzania health system context, the model will likely improve quality of services.

Limited Nosocomial Transmission of Drug-Resistant Tuberculosis, Moldova

Applying whole-genome-sequencing, we aimed to detect transmission events of multidrug-resistant/rifampin-resistant strains of Mycobacterium tuberculosis complex at a tuberculosis hospital in Chisinau, Moldova. We recorded ward, room, and bed information for each patient and monitored in-hospital transfers over 1 year. Detailed molecular and patient surveillance revealed only 2 nosocomial transmission events.

The Association Between Social Network Characteristics and Tuberculosis Infection Among Adults in 9 Rural Ugandan Communities

BACKGROUND

Social network analysis can elucidate tuberculosis transmission dynamics outside the home and may inform novel network-based case-finding strategies.

METHODS

We assessed the association between social network characteristics and prevalent tuberculosis infection among residents (aged ≥15 years) of 9 rural communities in Eastern Uganda. Social contacts named during a census were used to create community-specific nonhousehold social networks. We evaluated whether social network structure and characteristics of first-degree contacts (sex, human immunodeficiency virus [HIV] status, tuberculosis infection) were associated with revalent tuberculosis infection (positive tuberculin skin test [TST] result) after adjusting for individual-level risk factors (age, sex, HIV status, tuberculosis contact, wealth, occupation, and Bacillus Calmette-Guérin [BCG] vaccination) with targeted maximum likelihood estimation.

RESULTS

Among 3 335 residents sampled for TST, 32% had a positive TST results and 4% reported a tuberculosis contact. The social network contained 15 328 first-degree contacts. Persons with the most network centrality (top 10%) (adjusted risk ratio, 1.3 [95% confidence interval, 1.1-1.1]) and the most (top 10%) male contacts (1.5 [1.3-1.9]) had a higher risk of prevalent tuberculosis, than those in the remaining 90%. People with ≥1 contact with HIV (adjusted risk ratio, 1.3 [95% confidence interval, 1.1-1.6]) and ≥2 contacts with tuberculosis infection were more likely to have tuberculosis themselves (2.6 [ 95% confidence interval: 2.2-2.9]).

CONCLUSIONS

Social networks with higher centrality, more men, contacts with HIV, and tuberculosis infection were positively associated with tuberculosis infection. Tuberculosis transmission within measurable social networks may explain prevalent tuberculosis not associated with a household contact. Further study on network-informed tuberculosis case finding interventions is warranted.

Attitudes of Healthcare Workers about Prevention and Control of Nosocomial Multidrug-Resistant Tuberculosis Infection in Two Top-Ranked Tuberculosis Specialized Public Hospitals of Ethiopia

Background

Tuberculosis (TB) exists as a human curse since antiquity. Around 9.5 million cases and 1.5 million deaths were reported due to TB in 2021. Ethiopia is one of the high-burdenmultidrug-resistant (MDR) TB countries. MDR-TB is acquired either by poor adherence to treatment or by primary infection with a drug-resistant strain, which has a high transmission rate from patients to healthcare workers (HCWs). Hospital outbreaks of MDR-TB are common in Africa. Hence, this study aimed to score the attitude of HCWs working in the two nationally top-rankedTB-specialized hospitals in Ethiopia, Saint Peter's and ALERT TB-specialized public hospitals about the infection prevention and control (IPC) of nosocomial MDR-TB.

Methods

A cross-sectional study was conducted from December 1, 2020, to March 31, 2021. A simple random sampling method was applied to select 384 HCWs. The data collection tool was a self-administered interview structured questionnaire. The data were analyzed using SPSS software. Descriptive statistics were applied to score attitude. Bivariate and multivariable logistic regression models were performed to identify the independent determinants of attitude. The odds ratio was used to test the degree of association between variables at a 95% confidence interval (CI). The level of statistical significance was fixed at p value < 0.05.

Results

Among the respondents, 87% of the HCWs held favourable attitudes about the nosocomial MDR-TB-IPC. The favourable attitude score had a significant association with the monthly salary earned between 7001 and 9000 ETB (Ethiopian Birr) (AOR = 3.34, 95% CI: 1.11, 10.05) and the previous training obtained on TB/MDR-TB (AOR = 2.96, 95% CI: 1.32, 6.62).

Conclusions

Almost one in seven HCWs has an unfavourable attitude. Prior training received and earning monthly income above 7000 ETB are independent determinants of a favourable attitude score. Refreshment training and a reasonable increment in monthly income should be strengthened in TB-specialized hospitals in Ethiopia.

Transmissibility of tuberculosis among students and non-students: an occupational-specific mathematical modelling

BACKGROUND

Recently, despite the steady decline in the tuberculosis (TB) epidemic globally, school TB outbreaks have been frequently reported in China. This study aimed to quantify the transmissibility of Mycobacterium tuberculosis (MTB) among students and non-students using a mathematical model to determine characteristics of TB transmission.

METHODS

We constructed a dataset of reported TB cases from four regions (Jilin Province, Xiamen City, Chuxiong Prefecture, and Wuhan City) in China from 2005 to 2019. We classified the population and the reported cases under student and non-student groups, and developed two mathematical models [nonseasonal model (Model A) and seasonal model (Model B)] based on the natural history and transmission features of TB. The effective reproduction number (Reff) of TB between groups were calculated using the collected data.

RESULTS

During the study period, data on 456,423 TB cases were collected from four regions: students accounted for 6.1% of cases. The goodness-of-fit analysis showed that Model A had a better fitting effect (P < 0.001). The average Reff of TB estimated from Model A was 1.68 [interquartile range (IQR): 1.20-1.96] in Chuxiong Prefecture, 1.67 (IQR: 1.40-1.93) in Xiamen City, 1.75 (IQR: 1.37-2.02) in Jilin Province, and 1.79 (IQR: 1.56-2.02) in Wuhan City. The average Reff of TB in the non-student population was 23.30 times (1.65/0.07) higher than that in the student population.

CONCLUSIONS

The transmissibility of MTB remains high in the non-student population of the areas studied, which is still dominant in the spread of TB. TB transmissibility from the non-student-to-student-population had a strong influence on students. Specific interventions, such as TB screening, should be applied rigorously to control and to prevent TB transmission among students.

Mycobacterium tuberculosis Transmission in High-Incidence Settings-New Paradigms and Insights

Tuberculosis has affected humankind for thousands of years, but a deeper understanding of its cause and transmission only arose after Robert Koch discovered Mycobacterium tuberculosis in 1882. Valuable insight has been gained since, but the accumulation of knowledge has been frustratingly slow and incomplete for a pathogen that remains the number one infectious disease killer on the planet. Contrast that to the rapid progress that has been made in our understanding SARS-CoV-2 (the cause of COVID-19) aerobiology and transmission. In this Review, we discuss important historical and contemporary insights into M. tuberculosis transmission. Historical insights describing the principles of aerosol transmission, as well as relevant pathogen, host and environment factors are described. Furthermore, novel insights into asymptomatic and subclinical tuberculosis, and the potential role this may play in population-level transmission is discussed. Progress towards understanding the full spectrum of M. tuberculosis transmission in high-burden settings has been hampered by sub-optimal diagnostic tools, limited basic science exploration and inadequate study designs. We propose that, as a tuberculosis field, we must learn from and capitalize on the novel insights and methods that have been developed to investigate SARS-CoV-2 transmission to limit ongoing tuberculosis transmission, which sustains the global pandemic.

Transmission visualizations of healthcare infection clusters: A scoping review

OBJECTIVE

To evaluate infectious pathogen transmission data visualizations in outbreak publications.

DESIGN

Scoping review.

METHODS

Medline was searched for outbreak investigations of infectious diseases within healthcare facilities that included ≥1 data visualization of transmission using data observable by an infection preventionist showing temporal and/or spatial relationships. Abstracted data included the nature of the cluster(s) (pathogen, scope of transmission, and individuals involved) and data visualization characteristics including visualization type, transmission elements, and software.

RESULTS

From 1,957 articles retrieved, we analyzed 30 articles including 37 data visualizations. The median cluster size was 20.5 individuals (range, 7-1,963) and lasted a median of 214 days (range, 12-5,204). Among the data visualization types, 10 (27%) were floor-plan transmission maps, 6 (16%) were timelines, 11 (30%) were transmission networks, 3 (8%) were Gantt charts, 4 (11%) were cluster map, and 4 (11%) were other types. In addition, 26 data visualizations (70%) contained spatial elements, 26 (70%) included person type, and 19 (51%) contained time elements. None of the data visualizations contained contagious periods and only 2 (5%) contained symptom-onset date.

CONCLUSIONS

The data visualizations of healthcare-associated infectious disease outbreaks in the systematic review were diverse in type and visualization elements, though no data visualization contained all elements important to deriving hypotheses about transmission pathways. These findings aid in understanding the visualizing transmission pathways by describing essential elements of the data visualization and will inform the creation of a standardized mapping tool to aid in earlier initiation of interventions to prevent transmission.

Tuberculosis attributed to transmission within healthcare facilities, Botswana—The Kopanyo Study

Objective:

Healthcare facilities are a well-known high-risk environment for transmission of M. tuberculosis, the etiologic agent of tuberculosis (TB) disease. However, the link between M. tuberculosis transmission in healthcare facilities and its role in the general TB epidemic is unknown. We estimated the proportion of overall TB transmission in the general population attributable to healthcare facilities.

Methods:

We combined data from a prospective, population-based molecular epidemiologic study with a universal electronic medical record (EMR) covering all healthcare facilities in Botswana to identify biologically plausible transmission events occurring at the healthcare facility. Patients with M. tuberculosis isolates of the same genotype visiting the same facility concurrently were considered an overlapping event. We then used TB diagnosis and treatment data to categorize overlapping events into biologically plausible definitions. We calculated the proportion of overall TB cases in the cohort that could be attributable to healthcare facilities.

Results:

In total, 1,881 participants had TB genotypic and EMR data suitable for analysis, resulting in 46,853 clinical encounters at 338 healthcare facilities. We identified 326 unique overlapping events involving 370 individual patients; 91 (5%) had biologic plausibility for transmission occurring at a healthcare facility. A sensitivity analysis estimated that 3%–8% of transmission may be attributable to healthcare facilities.

Conclusions:

Although effective interventions are critical in reducing individual risk for healthcare workers and patients at healthcare facilities, our findings suggest that development of targeted interventions aimed at community transmission may have a larger impact in reducing TB.

Predicting Airborne Infection Risk: Association Between Personal Ambient Carbon Dioxide Level Monitoring and Incidence of Tuberculosis Infection in South African Health Workers

BACKGROUND

High rates of tuberculosis (TB) transmission occur in hospitals in high-incidence countries, yet there is no validated way to evaluate the impact of hospital design and function on airborne infection risk. We hypothesized that personal ambient carbon dioxide (CO2) monitoring could serve as a surrogate measure of rebreathed air exposure associated with TB infection risk in health workers (HWs).

METHODS

We analyzed baseline and repeat (12-month) interferon-γ release assay (IGRA) results in 138 HWs in Cape Town, South Africa. A random subset of HWs with a baseline negative QuantiFERON Plus (QFT-Plus) underwent personal ambient CO2 monitoring.

RESULTS

Annual incidence of TB infection (IGRA conversion) was high (34%). Junior doctors were less likely to have a positive baseline IGRA than other HWs (OR, 0.26; P = .005) but had similar IGRA conversion risk. IGRA converters experienced higher median CO2 levels compared to IGRA nonconverters using quantitative QFT-Plus thresholds of ≥0.35 IU/mL (P < .02) or ≥1 IU/mL (P < .01). Median CO2 levels were predictive of IGRA conversion (odds ratio [OR], 2.04; P = .04, ≥1 IU/mL threshold). Ordinal logistic regression demonstrated that the odds of a higher repeat quantitative IGRA result increased by almost 2-fold (OR, 1.81; P = .01) per 100 ppm unit increase in median CO2 levels, suggesting a dose-dependent response.

CONCLUSIONS

HWs face high occupational TB risk. Increasing median CO2 levels (indicative of poor ventilation and/or high occupancy) were associated with higher likelihood of HW TB infection. Personal ambient CO2 monitoring may help target interventions to decrease TB transmission in healthcare facilities and help HWs self-monitor occupational risk, with implications for other airborne infections including coronavirus disease 2019.

Estimating waiting times, patient flow, and waiting room occupancy density as part of tuberculosis infection prevention and control research in South African primary health care clinics

Transmission of respiratory pathogens, such as Mycobacterium tuberculosis and severe acute respiratory syndrome coronavirus 2, is more likely during close, prolonged contact and when sharing a poorly ventilated space. Reducing overcrowding of health facilities is a recognised infection prevention and control (IPC) strategy; reliable estimates of waiting times and 'patient flow' would help guide implementation. As part of the Umoya omuhle study, we aimed to estimate clinic visit duration, time spent indoors versus outdoors, and occupancy density of waiting rooms in clinics in KwaZulu-Natal (KZN) and Western Cape (WC), South Africa. We used unique barcodes to track attendees' movements in 11 clinics, multiple imputation to estimate missing arrival and departure times, and mixed-effects linear regression to examine associations with visit duration. 2,903 attendees were included. Median visit duration was 2 hours 36 minutes (interquartile range [IQR] 01:36-3:43). Longer mean visit times were associated with being female (13.5 minutes longer than males; p<0.001) and attending with a baby (18.8 minutes longer than those without; p<0.01), and shorter mean times with later arrival (14.9 minutes shorter per hour after 0700; p<0.001). Overall, attendees spent more of their time indoors (median 95.6% [IQR 46-100]) than outdoors (2.5% [IQR 0-35]). Attendees at clinics with outdoor waiting areas spent a greater proportion (median 13.7% [IQR 1-75]) of their time outdoors. In two clinics in KZN (no appointment system), occupancy densities of ~2.0 persons/m2 were observed in smaller waiting rooms during busy periods. In one clinic in WC (appointment system, larger waiting areas), occupancy density did not exceed 1.0 persons/m2 despite higher overall attendance. In this study, longer waiting times were associated with early arrival, being female, and attending with a young child. Occupancy of waiting rooms varied substantially between rooms and over the clinic day. Light-touch estimation of occupancy density may help guide interventions to improve patient flow.

FAST tuberculosis transmission control strategy speeds the start of tuberculosis treatment at a general hospital in Lima, Peru

Objective:

To evaluate the effect of the FAST (Find cases Actively, Separate safely, Treat effectively) strategy on time to tuberculosis diagnosis and treatment for patients at a general hospital in a tuberculosis-endemic setting.

Design:

Prospective cohort study with historical controls.

Participants:

Patients diagnosed with pulmonary tuberculosis during hospitalization at Hospital Nacional Hipolito Unanue in Lima, Peru.

Methods:

The FAST strategy was implemented from July 24, 2016, to December 31, 2019. We compared the proportion of patients with drug susceptibility testing and tuberculosis treatment during FAST to the 6-month period prior to FAST. Times to diagnosis and tuberculosis treatment were also compared using Kaplan-Meier plots and Cox regressions.

Results:

We analyzed 75 patients diagnosed with pulmonary tuberculosis through FAST. The historical cohort comprised 76 patients. More FAST patients underwent drug susceptibility testing (98.7% vs 57.8%; OR, 53.8; P < .001), which led to the diagnosis of drug-resistant tuberculosis in 18 (24.3%) of 74 of the prospective cohort and 4 (9%) of 44 of the historical cohort (OR, 3.2; P = .03). Overall, 55 FAST patients (73.3%) started tuberculosis treatment during hospitalization compared to 39 (51.3%) controls (OR, 2.44; P = .012). FAST reduced the time from hospital admission to the start of TB treatment (HR, 2.11; 95% CI, 1.39–3.21; P < .001).

Conclusions:

Using the FAST strategy improved the diagnosis of drug-resistant tuberculosis and the likelihood and speed of starting treatment among patients with pulmonary tuberculosis at a general hospital in a tuberculosis-endemic setting. In these settings, the FAST strategy should be considered to reduce tuberculosis transmission while simultaneously improving the quality of care.

Occupational Risk of Airborne Mycobacterium tuberculosis Exposure: A Situational Analysis in a Three-Tier Public Healthcare System in South Africa

This study aimed to detect airborne Mycobacterium tuberculosis (MTB) at nine public health facilities in three provinces of South Africa and determine possible risk factors that may contribute to airborne transmission. Personal samples (n = 264) and stationary samples (n = 327) were collected from perceived high-risk areas in district, primary health clinics (PHCs) and TB facilities. Quantitative real-time (RT) polymerase chain reaction (PCR) was used for TB analysis. Walkabout observations and work practices through the infection prevention and control (IPC) questionnaire were documented. Statistical analysis was carried out using Stata version 15.2 software. Airborne MTB was detected in 2.2% of samples (13/572), and 97.8% were negative. District hospitals and Western Cape province had the most TB-positive samples and identified risk areas included medical wards, casualty, and TB wards. MTB-positive samples were not detected in PHCs and during the summer season. All facilities reported training healthcare workers (HCWs) on TB IPC. The risk factors for airborne MTB included province, type of facility, area or section, season, lack of UVGI, and ineffective ventilation. Environmental monitoring, PCR, IPC questionnaire, and walkabout observations can estimate the risk of TB transmission in various settings. These findings can be used to inform management and staff to improve the TB IPC programmes.

Beijing genotype of Mycobacterium tuberculosis is associated with extensively drug-resistant tuberculosis: A global analysis

We found that the frequency of Beijing genotype among XDR-TB strains was high. The data in this study would help guide the TB control program, and we however need further investigation to confirm the reliability of the present findings.

Aptamer-Based Diagnostic Systems for the Rapid Screening of TB at the Point-of-Care

The transmission of Tuberculosis (TB) is very rapid and the burden it places on health care systems is felt globally. The effective management and prevention of this disease requires that it is detected early. Current TB diagnostic approaches, such as the culture, sputum smear, skin tuberculin, and molecular tests are time-consuming, and some are unaffordable for low-income countries. Rapid tests for disease biomarker detection are mostly based on immunological assays that use antibodies which are costly to produce, have low sensitivity and stability. Aptamers can replace antibodies in these diagnostic tests for the development of new rapid tests that are more cost effective; more stable at high temperatures and therefore have a better shelf life; do not have batch-to-batch variations, and thus more consistently bind to a specific target with similar or higher specificity and selectivity and are therefore more reliable. Advancements in TB research, in particular the application of proteomics to identify TB specific biomarkers, led to the identification of a number of biomarker proteins, that can be used to develop aptamer-based diagnostic assays able to screen individuals at the point-of-care (POC) more efficiently in resource-limited settings.

HIV-1 molecular transmission network among sexually transmitted populations in Liaoning Province, China

INTRODUCTION

In recent years, with the development of molecular epidemiology, molecular transmission networks based on evolutionary theory and sequence analysis have been widely used in research on human immunodeficiency virus (HIV)-1 transmission dynamics and precise intervention for high-risk populations. The HIV-1 molecular transmission network is a new method to study the population's access to the network, the characteristics of clustering, and the characteristics of interconnection in the network. Here, we analyzed the characteristics of the HIV-1 molecular transmission network of sexually transmitted people in Liaoning Province.

METHODS

A study of HIV-infected persons who were sexually transmitted in Liaoning Province from 2003 to 2019. HIV-1 RNA was extracted, amplified and sequenced, and a phylogenetic tree was constructed to determine the subtype using the well matched pol gene region sequence. The gene distance between sequences was calculated, the threshold was determined, and the molecular transmission network was constructed.

RESULTS

109 samples of pol gene region were obtained. The main subtype of HIV-1 was CRF01_AE, followed by B, CRF07_BC, etc. 12.8% of them were resistant to HIV. At the threshold of 0.55 gene distance, 60.6% of them entered the HIV-1 molecular transmission network. Workers, sample source voluntary counseling and testing, other testing, subtype B and drug resistance are the factors influencing the access to HIV-1 molecular transmission network. The subtype of CRF01_AE formed 6 clusters in the molecular transmission network. In the network, the difference of connection degree between different subtypes was statistically significant.

DISCUSSION

The three subtypes CRF01_AE, CRF07_BC and B that enter the molecular transmission network do not have interconnections, and they form clusters with each other. It shows that the risk of transmission among the three subtypes is less than the risk of transmission within each subtype. The factors affecting HIV-1 entry into the molecular transmission network were occupation, sample source, genotype and drug resistance. The L33F mutation at the HIV-1 resistance mutation site constitutes the interconnection in the largest transmission cluster in the network. The epidemiological characteristics of HIV-infected persons in each molecular transmission cluster show that 97% of the study subjects come from the same area and have a certain spatial aggregation.

CONCLUSION

Constructing a molecular transmission network and conducting long-term monitoring, while taking targeted measures to block the spread of HIV can achieve precise prevention and control.

Estimating ventilation rates in rooms with varying occupancy levels: Relevance for reducing transmission risk of airborne pathogens

BACKGROUND

In light of the role that airborne transmission plays in the spread of SARS-CoV-2, as well as the ongoing high global mortality from well-known airborne diseases such as tuberculosis and measles, there is an urgent need for practical ways of identifying congregate spaces where low ventilation levels contribute to high transmission risk. Poorly ventilated clinic spaces in particular may be high risk, due to the presence of both infectious and susceptible people. While relatively simple approaches to estimating ventilation rates exist, the approaches most frequently used in epidemiology cannot be used where occupancy varies, and so cannot be reliably applied in many of the types of spaces where they are most needed.

METHODS

The aim of this study was to demonstrate the use of a non-steady state method to estimate the absolute ventilation rate, which can be applied in rooms where occupancy levels vary. We used data from a room in a primary healthcare clinic in a high TB and HIV prevalence setting, comprising indoor and outdoor carbon dioxide measurements and head counts (by age), taken over time. Two approaches were compared: approach 1 using a simple linear regression model and approach 2 using an ordinary differential equation model.

RESULTS

The absolute ventilation rate, Q, using approach 1 was 2407 l/s [95% CI: 1632-3181] and Q from approach 2 was 2743 l/s [95% CI: 2139-4429].

CONCLUSIONS

We demonstrate two methods that can be used to estimate ventilation rate in busy congregate settings, such as clinic waiting rooms. Both approaches produced comparable results, however the simple linear regression method has the advantage of not requiring room volume measurements. These methods can be used to identify poorly-ventilated spaces, allowing measures to be taken to reduce the airborne transmission of pathogens such as Mycobacterium tuberculosis, measles, and SARS-CoV-2.

Bibliometric Analysis on Tuberculosis and Tuberculosis-Related Research Trends in Africa: A Decade-Long Study

Tuberculosis is one of the oldest known diseases and the leading communicable cause of deaths worldwide. Although several studies have been carried out on tuberculosis, no research has examined the publication trends in this area. Hence, this study aimed to fill the gap by conducting a bibliometric study in publications trends on tuberculosis and tuberculosis-related studies in Africa from 2010–2019 and explore the hotspots. Information in published documents on tuberculosis and its related studies from 2010 to 2019 were retrieved from the Web of Science (WoS) database. The bibliometric tool biblioshiny and Microsoft Excel 2016 were used to analyse the top leading journals, top cited documents, authors’ country production, country collaboration networks, most relevant authors, authors’ impacts, most relevant authors by corresponding author, most cited countries, university collaborations, most relevant affiliations, conceptual structural maps, title word co-occurrence networks, collaboration and significance of individual sources, university, country and keyword relations. A total of 3945 published documents were retrieved. The analyses showed that European Respiratory Journal was the leading journal in publications on tuberculosis studies with a total of 452 published articles, the WHO 2012 report was the most cited document with 2485 total citations while South Africa was the most productive country in tuberculosis publications as well as the leading country with the highest co-authorship collaboration. Analysis of top relevant authors revealed that Anonymous (133) and Dheda (44) were the two topmost relevant authors of tuberculosis publications, South Africa was the most relevant country by corresponding authors and the topmost cited country for tuberculosis publications. Furthermore, analysis of the university collaborations network showed that the University of Cape Town was the topmost university in Africa with the highest collaboration network, tuberculosis as a word had the highest co-occurrence network while the Three Field Plot diagram revealed the relations between universities, keywords and countries. This study provides a quantitative and qualitative analyses of the leading journals, most cited published articles, title word occurrences, and most relevant authors in published documents on tuberculosis and tuberculosis related studies from 2010–2019.

Knowledge, Attitude, and Practices on Drug-Resistant Tuberculosis Infection Control in Nepal: A Cross-Sectional Study

Drug-resistant tuberculosis (DR-TB) transmission is an important problem, particularly in low-income settings. This study is aimed at assessing the knowledge, attitude, and practices of DR-TB infection control among the healthcare workers under the National Tuberculosis Control Program in Nepal. In this cross-sectional study, we studied the healthcare workers from all the 11 functioning DR-TB treatment centers across Nepal in March 2018. Through face-to-face interviews, trained data collectors collected data on the characteristics of healthcare workers, their self-reported knowledge, attitude, and practice on DR-TB infection control. We entered the data in Microsoft Excel and analyzed in the R statistical software. We assigned a score of one to the correct response and zero to the incorrect or no response and calculated a composite score in each of the knowledge, attitude, and practice domains. We ascertained the healthcare workers as having good knowledge, appropriate attitude, and optimal practices when the composite score was ≥50%. We summarized the numerical variables with median (interquartile range (IQR)) and the categorical variables with proportions. We ran appropriate correlation tests to identify relationships between knowledge, attitude, and practice scores. We regarded a p value of <0.05 as significant. A total of 95 out of 102 healthcare workers responded. There were 46 male respondents. The median age was 33 years (IQR 26-42). Most of them (53, 55.79%) were midlevel paramedics. We found 91 (95.79%) respondents had good knowledge, 49 (51.58%) had an appropriate attitude, and 35 (36.84%) had optimal practices on DR-TB infection control. We found a statistically significant positive correlation between attitude and practice scores (ρ = 0.37, p ≤ 0.001). The healthcare workers at the DR-TB treatment centers in Nepal have good knowledge of DR-TB infection control, but it did not translate into an appropriate attitude or optimal practices.

The Importance of Heterogeneity to the Epidemiology of Tuberculosis

Although less well-recognized than for other infectious diseases, heterogeneity is a defining feature of tuberculosis (TB) epidemiology. To advance toward TB elimination, this heterogeneity must be better understood and addressed. Drivers of heterogeneity in TB epidemiology act at the level of the infectious host, organism, susceptible host, environment, and distal determinants. These effects may be amplified by social mixing patterns, while the variable latent period between infection and disease may mask heterogeneity in transmission. Reliance on notified cases may lead to misidentification of the most affected groups, as case detection is often poorest where prevalence is highest. Assuming that average rates apply across diverse groups and ignoring the effects of cohort selection may result in misunderstanding of the epidemic and the anticipated effects of control measures. Given this substantial heterogeneity, interventions targeting high-risk groups based on location, social determinants, or comorbidities could improve efficiency, but raise ethical and equity considerations.

Factors influencing the length of hospital stay during the intensive phase of multidrug-resistant tuberculosis treatment at Amhara regional state hospitals, Ethiopia: a retrospective follow up study

Background

The length of hospital stay is the duration of hospitalization, which reflects disease severity and resource utilization indirectly. Generally, tuberculosis is considered an ambulatory disease that could be treated at DOTs clinics; however, admission remains an essential component for patients’ clinical stabilization. Hence, this study aimed to identify factors influencing hospital stay length during the intensive phase of multidrug-resistant tuberculosis treatment.

Methods

A retrospective follow-up study was conducted at three hospitals, namely the University of Gondar comprehensive specialized, Borumeda, and Debremarkos referral hospitals from September 2010 to December 2016 (n = 432). Data extracted from hospital admission/discharge logbooks and individual patient medical charts. A binary logistic regression analysis was used to identify factors associated with more extended hospital stays during the intensive phase of multidrug-resistant tuberculosis treatment.

Result

Most patients (93.5%) had a pulmonary form of multidrug-resistant tuberculosis and 26.2% had /TB/HIV co-infections. The median length of hospital stays was 62 (interquartile range from 36 to 100) days. The pulmonary form of tuberculosis (Adjusted odds ratio [AOR], 3.47, 95% confidence interval [CI]; 1.31 to 9.16), bedridden functional status (AOR = 2.88, 95%CI; 1.29 to 6.43), and adverse drug effects (AOR = 2.11, 95%CI; 1.35 to 3.30) were factors associated with extended hospital stays.

Conclusion

This study revealed that the length of hospital-stay differed significantly between the hospitals. The pulmonary form of tuberculosis decreased functional status at admission and reported adverse drug reactions were determinants of more extended hospital stays. These underscore the importance of early case detection and prompt treatment of adverse drug effects.

Exploring the usefulness of molecular epidemiology of tuberculosis in Africa: a systematic review

BACKGROUND

Tuberculosis (TB) is caused by Mycobacterium tuberculosis complex (MTBC) and remains a serious global public health threat, especially in resource-limited settings such as the African region. Recent developments in molecular epidemiology tools have significantly improved our understanding of TB transmission patterns and revealed the high genetic diversity of TB isolates across geographical entities in Africa. This study reports the results of a systematic review of current knowledge about MTBC strain diversity and geographical distribution in African regions.

METHODS

Search tools (PubMed, Embase, Popline, OVID and Africa Wide Information) were employed to identify the relevant literature about prevalence, strain diversity, and geographic distribution of MTBC infection in Africa.

RESULTS

A total of 59 articles from 739 citations met our inclusion criteria. Most articles reported about patients with presumptive pulmonary TB (73%), fewer reports were on retreatment and treatment failure cases (12%), and presumptive drug resistance cases (3%). Spoligotyping was the most used, alone in 21 studies and in parallel with either the Mycobacterial Interspersed Repetitive Units Variable Number of Tandem Repeats or the Restriction Fragment Length Polymorphism. Various TB lineages were observed across the African continent, with the originally European lineage 4 spotted in all countries studied.

CONCLUSION

TB molecular epidemiology tools have substantially improved our understanding of the MTBC circulating isolates, their evolution, and diversity in this highly endemic region of Africa. We found that only TB lineage 4 is present throughout all the continent and the clusters identified provides an extended insight into the disease transmission dynamics.

Bedaquiline resistance in drug-resistant tuberculosis HIV co-infected patients

Global tuberculosis (TB) control is threatened by drug resistance, with over 500 000 cases resistant to first-line drugs in 2018 [1]. Bedaquiline is a highly effective TB drug and has improved drug-resistant TB (DR-TB) outcomes in trial and programmatic settings [2, 3]. The World Health Organization (WHO) recommends its inclusion in most DR-TB regimens [4] and it is under further evaluation in clinical trials. There have been several reports of clinical bedaquiline resistance [5–8]. Resistance-associated variants (RAVs) in clinical isolates identified to date are almost exclusively caused by Rv0678 mutations which can raise Mycobacterium tuberculosis minimum inhibitory concentrations (MICs) for bedaquiline and clofazimine [9].

Genetic mutations linked to bedaquiline resistance were found before starting treatment and acquired during treatment in patients with drug-resistant TB and HIV in KwaZulu-Natal, South Africa. Routine bedaquiline resistance testing needs to be accelerated. http://bit.ly/2vnL4VY

Molecular epidemiology of drug resistant Mycobacterium tuberculosis in Africa: a systematic review

Background

The burden of drug resistant tuberculosis in Africa is largely driven by the emergence and spread of multidrug resistant (MDR) and extensively drug resistant (XDR) Mycobacterium tuberculosis strains. MDR-TB is defined as resistance to isoniazid and rifampicin, while XDR-TB is defined as MDR-TB with added resistance to any of the second line injectable drugs and any fluoroquinolone.

The highest burden of drug resistant TB is seen in countries further experiencing an HIV epidemic. The molecular mechanisms of drug resistance as well as the evolution of drug resistant TB strains have been widely studied using various genotyping tools. The study aimed to analyse the drug resistant lineages in circulation and transmission dynamics of these lineages in Africa by describing outbreaks, nosocomial transmission and migration. Viewed as a whole, this can give a better insight into the transmission dynamics of drug resistant TB in Africa.

Methods

A systematic review was performed on peer reviewed original research extracted from PubMed reporting on the lineages associated with drug resistant TB from African countries, and their association with outbreaks, nosocomial transmission and migration. The search terms “Tuberculosis AND drug resistance AND Africa AND (spoligotyping OR molecular epidemiology OR IS6110 OR MIRU OR DNA fingerprinting OR RFLP OR VNTR OR WGS)” were used to identify relevant articles reporting the molecular epidemiology of drug resistant TB in Africa.

Results

Diverse genotypes are associated with drug resistant TB in Africa, with variations in strain predominance within the continent. Lineage 4 predominates across Africa demonstrating the ability of “modern strains” to adapt and spread easily. Most studies under review reported primary drug resistance as the predominant type of transmission. Drug resistant TB strains are associated with community and nosocomial outbreaks involving MDR- and XDR-TB strains. The under-use of molecular epidemiological tools is of concern, resulting in gaps in knowledge of the transmission dynamics of drug resistant TB on the continent.

Conclusions

Genetic diversity of M. tuberculosis strains has been demonstrated across Africa implying that diverse genotypes are driving the epidemiology of drug resistant TB across the continent.

Impact of introducing fluorescent microscopy on hospital tuberculosis control: A before-after study at a high caseload medical center in Taiwan

Background

Undiagnosed tuberculosis (TB) patients hospitalized because of comorbidities constitute a challenge to TB control in hospitals. We aimed to assess the impact of introducing highly sensitive fluorescent microscopy for examining sputum smear to replace conventional microscopy under a high TB risk setting.

Methods

We measured the impact of switch to fluorescent microscopy on the smear detection rate of culture-confirmed pulmonary TB, timing of respiratory isolation, and total non-isolated infectious person-days in hospital at a high-caseload medical center (approximately 400 TB cases annually) in Taipei. Multivariable Cox regression was applied to adjust for effects of covariates. The effect attributable to the improved smear detection rate was determined using causal mediation analysis.

Results

After switch to fluorescence microscopy, median non-isolated infectious duration decreased from 12.5 days to 3 days (P<0.001). Compared with conventional microscopy, fluorescence microscopy increased sputum smear detection rate by two-fold (for all patients: from 22.8% to 48.1%, P<0.001; for patients with cavitary lung lesion: from 43% to 82%, P = 0.029) and was associated with a 2-fold higher likelihood of prompt respiratory isolation (odds ratio mediated by the increase in sputum smear detection rate: 1.8, 95% CI 1.3–2.5). Total non-isolated infectious patient-days in hospital decreased by 69% (from 4,778 patient-days per year to 1,502 patient-days per year).

Conclusions

In a high TB caseload setting, highly sensitive rapid diagnostic tools could substantially improve timing of respiratory isolation and reduce the risk of nosocomial TB transmission.

Treatment as prevention and other interventions to reduce transmission of multidrug-resistant tuberculosis

Drug-resistant tuberculosis (DR-TB) represents a major programmatic challenge at the national and global levels. Only ∼30% of patients with multidrug-resistant TB (MDR-TB) were diagnosed, and ∼25% were initiated on treatment for MDR-TB in 2016. Increasing evidence now points towards primary transmission of DR-TB, rather than inadequate treatment, as the main driver of the DR-TB epidemic. The cornerstone of DR-TB transmission prevention should be earlier diagnosis and prompt initiation of effective treatment for all patients with DR-TB. Despite the extensive scale-up of Xpert^® MTB/RIF testing, major implementation barriers continue to limit its impact. Although there is longstanding evidence in support of the rapid impact of treatment on patient infectiousness, delays in the initiation of effective DR-TB treatment persist, resulting in ongoing transmission. However, it is also imperative to address the burden of latent drug-resistant tuberculous infection because it is estimated that many DR-TB patients will become infectious before seeking care and encounter various diagnostic delays before treatment. Addressing latent DR-TB primarily consists of identifying, treating and following the contacts of patients with MDR-TB, typically through household contact evaluation. Adjunctive measures, such as improved ventilation and use of germicidal ultraviolet technology can further reduce TB transmission in high-risk congregate settings. Although many gaps remain in our biological understanding of TB transmission, implementation barriers to early diagnosis and rapid initiation of effective DR-TB treatment can and must be overcome if we are to impact DR-TB incidence in the short and long term.

Multidrug-Resistant Tuberculosis in Patients with Human Immunodeficiency Virus. Management Considerations within High-resourced Settings

The management of multidrug-resistant tuberculosis (MDR TB) is notably complex among patients with human immunodeficiency virus (HIV). TB treatment recommendations typically include very little information specific to HIV and MDR TB, which often is derived from clinical trials conducted in low-resource settings. Mortality rates among patients with HIV and MDR TB remain high. We reviewed the published literature and recommendations to synthesize possible patient management approaches demonstrated to improve treatment outcomes in high-resourced countries for patients with MDR TB and HIV. Approaches to diagnostic testing, impact and timing of antiretroviral therapy on mortality, anti-MDR TB and antiretroviral drug interactions, and the potential role for short-course MDR TB therapy are examined. The combination of antiretroviral therapy with expanded TB drug therapy, along with the management of immune reconstitution inflammatory syndrome, other potential HIV-associated opportunistic diseases, and drug toxicities, necessitate an integrated multidisciplinary patient care approach using public health case management and provider expertise in drug-resistant TB and HIV management.

Laboratory tools for tuberculosis control in a setting with a high burden of HIV/AIDS

Introduction. Nosocomial transmission of Mycobacterium tuberculosis is an important health issue and the detection of tuberculosis (TB) cases is the main tool for controlling this disease.Aim. We aimed to assess the possible occurrence of nosocomial transmission of M. tuberculosis in a reference hospital for HIV/AIDS patients and evaluate both the performance of the Xpert MTB/RIF (Xpert) platform and drug resistance profiles.Methodology. We evaluated the performance of the Xpert platform. Samples that tested positive on the BACTEC MGIT 320 (MGIT320) platform were submitted for genotyping and drug susceptibility testing.Results. In this study, pulmonary and extrapulmonary samples from 407 patients were evaluated, and among these, 15.5 % were diagnosed with TB by the MGIT320 platform, with a TB/HIV coinfection rate of 52.4 %. The Xpert platform gave positive results for TB for 11 samples with negative results on the MGIT320 platform. In the genotyping results, 53.3 % of the strains clustered; of these strains, half were in two of the four clusters formed, and the patients had visited the hospital on the same day. Drug resistance was observed in 11.7 % of the strains.Conclusion. Putative nosocomial transmission of M. tuberculosis was detected, showing that genotyping is a powerful approach for understanding the dynamics of M. tuberculosis transmission, especially in a high-burden TB and HIV landscape.

Pre-detection history of extensively drug-resistant tuberculosis in KwaZulu-Natal, South Africa

Antimicrobial-resistant (AMR) infections pose a major threat to global public health. Similar to other AMR pathogens, both historical and ongoing drug-resistant tuberculosis (TB) epidemics are characterized by transmission of a limited number of predominant Mycobacterium tuberculosis (Mtb) strains. Understanding how these predominant strains achieve sustained transmission, particularly during the critical period before they are detected via clinical or public health surveillance, can inform strategies for prevention and containment. In this study, we employ whole-genome sequence (WGS) data from TB clinical isolates collected in KwaZulu-Natal, South Africa to examine the pre-detection history of a successful strain of extensively drug-resistant (XDR) TB known as LAM4/KZN, first identified in a widely reported cluster of cases in 2005. We identify marked expansion of this strain concurrent with the onset of the generalized HIV epidemic 12 y prior to 2005, localize its geographic origin to a location in northeastern KwaZulu-Natal ∼400 km away from the site of the 2005 outbreak, and use protein structural modeling to propose a mechanism for how strain-specific rpoB mutations offset fitness costs associated with rifampin resistance in LAM4/KZN. Our findings highlight the importance of HIV coinfection, high preexisting rates of drug-resistant TB, human migration, and pathoadaptive evolution in the emergence and dispersal of this critical public health threat. We propose that integrating whole-genome sequencing into routine public health surveillance can enable the early detection and local containment of AMR pathogens before they achieve widespread dispersal.

The emergency response to multidrug-resistant tuberculosis in Daru, Western Province, Papua New Guinea, 2014-2017

SETTING

A response to an outbreak of multidrug-resistant tuberculosis (MDR-TB) on Daru Island, South Fly District (SFD), Western Province, Papua New Guinea (PNG) was implemented by a national emergency response taskforce.

OBJECTIVE

To describe programmatic interventions for TB in SFD and evaluate characteristics of TB case notifications, drug resistance and treatment outcomes.

DESIGN

This was a retrospective cohort study based on routine programmatic data for all patients enrolled on TB treatment at Daru General Hospital from 2014 to 2017.

RESULTS

The response involved high-level political commitment, joint planning, resource mobilisation, community engagement and strengthening TB case detection and treatment. Of 1548 people enrolled on TB treatment, 1208 (78%) had drug-susceptible TB (DS-TB) and 333 (21.5%) had MDR-TB. There was an increase in MDR-TB as a proportion of all TB. Treatment success rates increased over the study period from 55% to 86% for DS-TB, and from 70% to 81% for MDR-TB from 2014 to 2015. The 2014 case notification rate for TB in SFD was 1031/100 000, decreasing to 736/100 000 in 2017.

CONCLUSION

The outbreak was stabilised through the response from the national and provincial governments and international partners. Additional interventions are needed to decrease the TB burden in Daru.

The high-quality health system 'revolution': Re-imagining tuberculosis infection prevention and control

The Lancet Commission on High-Quality Health Systems called for a 'revolution' in the quality of care provided in low- and middle-income countries. We argue that this provides a helpful framework to demonstrate how effective tuberculosis infection prevention and control (TB IPC) implementation should be linked with health system strengthening, moving it from the silo of the national TB programmes. Using this framework, we identify and discuss links between TB IPC implementation and patient safety, human resources for health, prioritising person-centred care, building trust in health systems and refining the tools used to measure TB IPC implementation. Prioritising patient experience has been a recent addition to the definition of high-quality care. In high TB burden settings, the encounter with TB IPC measures may be a TB patient's initial contact with the healthcare system and may cause feelings of stigmatisation. We advocate for re-imagining the way we implement TB IPC, by drawing on the principles of person-centred care through incorporating the experiences of people using healthcare services. Health workers who developed occupational TB also offer a unique perspective: they have both experienced TB IPC and have played a role in implementing it in their workplace. They can be powerful advocates for person-centred TB IPC implementation. Through framing TB IPC as part of health system strengthening and consciously including person-centred perspectives in TB IPC design, measurement and guidelines, we hope to influence future TB IPC research and practice.

Differentiating Epidemic from Endemic or Sporadic Infectious Disease Occurrence

One important scope of work of epidemiology is the investigation of infectious diseases that cluster in time and place. Clusters of infectious disease may represent outbreaks or epidemics in which the cases share in common a point source exposure or an infectious agent in a chain of transmission pathways. Investigations of outbreaks of an illness can facilitate identification of a source, risk, or cause of the illness. However, most infectious disease episodes occur not as part of any apparent outbreaks but as sporadic infections. Multiple sporadic infections that occur steadily in time and place are referred to as endemic disease. How does one investigate sources and risk factors for sporadic or endemic infections? As part of the Microbiology Spectrum Curated Collection: Advances in Molecular Epidemiology of Infectious Diseases, this review discusses limitations of traditional approaches and advantages of molecular epidemiology approaches to investigate sporadic and endemic infections. Using specific examples, the discussions show that most sporadic infections are actually part of unrecognized outbreaks and that what appears to be endemic disease occurrence is actually comprised of multiple small outbreaks. These molecular epidemiologic investigations have unmasked modes of transmission of infectious agents not known to cause outbreaks. They have also raised questions about the traditional ways to measure incidence and assess sources of drug-resistant infections in community settings. The discoveries made by the application of molecular microbiology methods in epidemiologic investigations have led to creation of new public health intervention strategies that have not been previously considered. *This article is part of a curated collection.

Institutional tuberculosis infection control in a rural sub-district in South Africa: A quality improvement study

Background

Tuberculosis (TB) is a major global health challenge, and South Africa is one of the high-burden countries. A national TB infection control (TBIC) guideline has stipulated three areas of infection control at health facilities: work practice and administrative control, environmental control, and personal protection for health workers.

Aim

The aim of this study was to identify the gaps and address the challenges in institutional TBIC.

Setting

The district hospital and a primary health care clinic within the Mossel Bay sub-district in the Western Cape.

Methods

According to the national TBIC draft guideline, a quality improvement cycle was used to evaluate and improve TBIC. Each facility had an existing infection and prevention control and occupational health and safety team, which were used as the audit teams.

Results

A baseline assessment was followed by a set of interventions, which did not show a significant improvement in TBIC. The difference between the pre- and post-intervention TB screening rate was not statistically significant. An assessment of time interval between 101 patients presenting with TB symptoms and diagnosed with TB was 4 days at baseline and post-intervention. Most of the anticipated improvements were dependent on the health workers’ adherence to the local TBIC policies, which emerged as an unexpected finding.

Conclusion

We found good managerial commitment reflected by the presence of various policies, guidelines, specific personnel and committees to deal with infection control in general. This study has created awareness about TBIC among staff and pointed out the complexity of health workers’ behaviour towards adhering to policies.

Transmission of drug-resistant tuberculosis in HIV-endemic settings

The emergence and expansion of the multidrug-resistant tuberculosis epidemic is a threat to the global control of tuberculosis. Multidrug-resistant tuberculosis is the result of the selection of resistance-conferring mutations during inadequate antituberculosis treatment. However, HIV has a profound effect on the natural history of tuberculosis, manifesting in an increased rate of disease progression, leading to increased transmission and amplification of multidrug-resistant tuberculosis. Interventions specific to HIV-endemic areas are urgently needed to block tuberculosis transmission. These interventions should include a combination of rapid molecular diagnostics and improved chemotherapy to shorten the duration of infectiousness, implementation of infection control measures, and active screening of multidrug-resistant tuberculosis contacts, with prophylactic regimens for individuals without evidence of disease. Development and improvement of the efficacy of interventions will require a greater understanding of the factors affecting the transmission of multidrug-resistant tuberculosis in HIV-endemic settings, including population-based molecular epidemiology studies. In this Series article, we review what we know about the transmission of multidrug-resistant tuberculosis in settings with high burdens of HIV and define the research priorities required to develop more effective interventions, to diminish ongoing transmission and the amplification of drug resistance.

Effect of Antiretroviral Therapy on Treatment Outcomes in a Prospective Study of Extensively Drug-Resistant Tuberculosis (XDR-TB) HIV Coinfection Treatment in KwaZulu-Natal, South Africa

BACKGROUND

Extensively drug-resistant tuberculosis (XDR-TB)/HIV coinfection has been associated with high mortality and poor TB outcomes. We performed a prospective study to comprehensively characterize a cohort of patients with XDR-TB.

METHODS

Adult patients with XDR-TB were enrolled at treatment initiation at a TB referral hospital in KwaZulu-Natal Province, South Africa, and followed through the end of treatment. Clinical data, questionnaires, adherence data, and sputum were collected monthly. Whole genome sequencing was performed on baseline Mycobacterium tuberculosis (MTB) isolates. Treatment outcomes were defined using standard definitions.

RESULTS

One hundred five patients with XDR-TB (76.1% HIV-infected) were enrolled from August 2009 to July 2011. Among HIV-coinfected patients, 82.5% were on antiretroviral therapy initially and 93.8% cumulatively over the study period. At 24 months, 31.4% had a successful outcome and 68.6% had an unsuccessful outcome with 41% mortality. Antiretroviral therapy was associated with improved mortality in HIV-coinfected patients (P = 0.05), as was TB culture conversion (P < 0.0001). On whole genome sequencing, most strains were LAM4/KZN lineage (68%), with few single nucleotide polymorphism differences.

CONCLUSIONS

Despite improved HIV care, treatment outcomes and mortality were only modestly improved compared with previous South African XDR-TB/HIV treatment cohorts. Of note, this study was completed before the introduction of new antimycobacterial agents (eg, bedaquiline and delamanid). As new TB drugs and regimens become available, it is important to monitor treatment to ensure that benefits seen in clinical trials are reproduced in high-burden, low-resource settings.

Improvement in tuberculosis infection control practice via technical support in two regions of Ethiopia

BACKGROUND

Globally recommended measures for comprehensive tuberculosis (TB) infection control (IC) are inadequately practiced in most health care facilities in Ethiopia. The aim of this study was to assess the extent of implementation of TB IC measures before and after introducing a comprehensive technical support package in two regions of Ethiopia.

METHODS

We used a quasi-experimental design, whereby a baseline assessment of TB IC practices in 719 health care facilities was conducted between August and October 2013. Based on the assessment findings, we supported implementation of a comprehensive package of interventions. Monitoring was done on a quarterly basis, and one-year follow-up data were collected on September 30, 2014. We used the Student's t-test and chi-squared tests, respectively, to examine differences before and after the interventions and to test for inter-regional and inter-facility associations.

RESULTS

At baseline, most of the health facilities (69%) were reported to have separate TB clinics. In 55.2% of the facilities, it was also reported that window opening was practiced. Nevertheless, triaging was practiced in only 19.3% of the facilities. Availability of an IC committee and IC plan was observed in 29.11 and 4.65% of facilities, respectively. Health care workers were nearly three times as likely to develop active TB as the general population. After 12 months of implementation, availability of a separate TB room, TB IC committee, triage, and TB IC plan had increased, respectively, by 18, 32, 44, and 51% (p < 0.001).

CONCLUSIONS

After 1 year of intervention, the TB IC practices of the health facilities have significantly improved. However, availability of separate TB rooms and existence of TB IC committees remain suboptimal. The burden of TB among health care workers is higher than in the general population. TB IC measures must be strengthened to reduce TB transmission among health workers.

Extensively drug-resistant tuberculosis in South Africa: genomic evidence supporting transmission in communities

Despite evidence that transmission is driving an extensively drug-resistant TB (XDR-TB) epidemic, our understanding of where and between whom transmission occurs is limited. We sought to determine whether there was genomic evidence of transmission between individuals without an epidemiologic connection.We conducted a prospective study of XDR-TB patients in KwaZulu-Natal, South Africa, during the 2011-2014 period. We collected sociodemographic and clinical data, and identified epidemiologic links based on person-to-person or hospital-based connections. We performed whole-genome sequencing (WGS) on the Mycobacterium tuberculosis isolates and determined pairwise single nucleotide polymorphism (SNP) differences.Among 404 participants, 123 (30%) had person-to-person or hospital-based links, leaving 281 (70%) epidemiologically unlinked. The median SNP difference between participants with person-to-person and hospital-based links was 10 (interquartile range (IQR) 8-24) and 16 (IQR 10-23), respectively. The median SNP difference between unlinked participants and their closest genomic link was 5 (IQR 3-9) and half of unlinked participants were within 7 SNPs of at least five participants.The majority of epidemiologically-unlinked XDR-TB patients had low pairwise SNP differences with at least one other participant, consistent with transmission. These data suggest that much of transmission may result from casual contact in community settings between individuals not known to one another.

Prevalence and risk factors of tuberculosis in developing countries through health care workers

In the last two decades, tuberculosis (TB) have threatened the public across the globe and continuing new TB cases and their transmission pooled with the global emergence of drug-resistant strains present an enduring occupational risk for health care workers (HCWs). Since last decade, government and funding agencies has given a significant amount of funds to tackle the problem of TB infection among medical staff or HCW in hospitals of developing countries, but the effects of these efforts have not yet been reported. Working environments are the major risk factors for TB infections among the HCW in hospital settings. Twenty-two high burden countries endorsed to the preponderance of worldwide tuberculosis cases in 2015. Urgent preventive strategies and mediations are needed to ensure the safety and sustained availability of these exquisite healthcare resources. This timeline review will provide the theoretical basis of high TB burden among the HCW which can be used for further improvement in strategies for the prevention of TB infections in hospital settings and provide a reliable basis for improving the personal health of HCW or medical staff.

Where is tuberculosis transmission happening? Insights from the literature, new tools to study transmission and implications for the elimination of tuberculosis

More than 10 million new cases of tuberculosis (TB) are diagnosed worldwide each year. The majority of these cases occur in low- and middle-income countries where the TB epidemic is predominantly driven by transmission. Efforts to 'end TB' will depend upon our ability to halt ongoing transmission. However, recent studies of new approaches to interrupt transmission have demonstrated inconsistent effects on reducing population-level TB incidence. TB transmission occurs across a wide range of settings, that include households and hospitals, but also community-based settings. While home-based contact investigations and infection control programmes in hospitals and clinics have a successful track record as TB control activities, there is a gap in our knowledge of where, and between whom, community-based transmission of TB occurs. Novel tools, including molecular epidemiology, geospatial analyses and ventilation studies, provide hope for improving our understanding of transmission in countries where the burden of TB is greatest. By integrating these diverse and innovative tools, we can enhance our ability to identify transmission events by documenting the opportunity for transmission-through either an epidemiologic or geospatial connection-alongside genomic evidence for transmission, based upon genetically similar TB strains. A greater understanding of locations and patterns of transmission will translate into meaningful improvements in our current TB control activities by informing targeted, evidence-based public health interventions.

FAST implementation in Bangladesh: high frequency of unsuspected tuberculosis justifies challenges of scale-up

SETTING

National Institute of Diseases of the Chest and Hospital, Dhaka; Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders, Dhaka; and Chittagong Chest Disease Hospital, Chittagong, Bangladesh.

OBJECTIVE

To present operational data and discuss the challenges of implementing FAST (Find cases Actively, Separate safely and Treat effectively) as a tuberculosis (TB) transmission control strategy.

DESIGN

FAST was implemented sequentially at three hospitals.

RESULTS

Using Xpert® MTB/RIF, 733/6028 (12.2%, 95%CI 11.4-13.0) patients were diagnosed with unsuspected TB. Patients with a history of TB who were admitted with other lung diseases had more than twice the odds of being diagnosed with unsuspected TB as those with no history of TB (OR 2.6, 95%CI 2.2-3.0, P < 0.001). Unsuspected multidrug-resistant TB (MDR-TB) was diagnosed in 89/1415 patients (6.3%, 95%CI 5.1-7.7). Patients with unsuspected TB had nearly five times the odds of being diagnosed with MDR-TB than those admitted with a known TB diagnosis (OR 4.9, 95%CI 3.1-7.6, P < 0.001). Implementation challenges include staff shortages, diagnostic failure, supply-chain issues and reliance on external funding.

CONCLUSION

FAST implementation revealed a high frequency of unsuspected TB in hospitalized patients in Bangladesh. Patients with a previous history of TB have an increased risk of being diagnosed with unsuspected TB. Ensuring financial resources, stakeholder engagement and laboratory capacity are important for sustainability and scalability.

Measuring ventilation and modelling M. tuberculosis transmission in indoor congregate settings, rural KwaZulu-Natal

SETTING: Molecular epidemiology suggests that most Mycobacterium tuberculosis transmission in high-burden settings occurs outside the home.

OBJECTIVE: To estimate the risk of M. tuberculosis transmission inside public buildings in a high TB burden community in KwaZulu-Natal, South Africa.

DESIGN: Carbon dioxide (CO₂) sensors were placed inside eight public buildings. Measurements were used with observations of occupancy to estimate infection risk using an adaptation of the Wells-Riley equation. Ventilation modelling using CONTAM was used to examine the impact of low-cost retrofits on transmission in a health clinic.

RESULTS: Measurements indicate that infection risk in the church, classroom and clinic waiting room would be high with typical ventilation, occupancy levels and visit durations. For example, we estimated that health care workers in a clinic waiting room had a 16.9–24.5% annual risk of M. tuberculosis infection. Modelling results indicate that the simple addition of two new windows allowing for cross-ventilation, at a cost of US$330, would reduce the annual risk to health care workers by 57%.

CONCLUSIONS: Results indicate that public buildings in this community have a range of ventilation and occupancy characteristics that may influence transmission risks. Simple retrofits may result in dramatic reductions in M. tuberculosis transmission, and intervention studies should therefore be considered.

Healthcare associated infection and its risk factors among patients admitted to a tertiary hospital in Ethiopia: longitudinal study

Background

Healthcare associated infection (HAI) is alarmingly increasing in low income settings. In Ethiopia, the burden of HAI is still not well described.

Methods

Longitudinal study was conducted from May to September, 2016. All wards of Jimma University Medical Centre were included. The incidence, prevalence and risk factors of healthcare associated infection were determined. A total of 1015 admitted patients were followed throughout their hospital stay. Biological specimens were collected from all patients suspected to have hospital aquired infection. The specimens were processed by standard microbiological methods to isolate and identify bacteria etiology. Clinical and laboratory data were collected using structured case report formats.

Results

The incidence rate of hospital acquired infection was 28.15 [95% C.I:24.40,32.30] per 1000 patient days while the overall prevalence was 19.41% (95% C.I: (16.97–21.85). The highest incidence of HAI was seen in intensive care unit [207.55 (95% C.I:133.40,309.1) per 1000 patient days] and the lowest incidence was reported from ophthalmology ward [0.98 (95% C.I: 0.05,4.90) per 1000patient days]. Among patients who underwent surgical procedure, the risk of HAI was found to be high in those with history of previous hospitalization (ARR = 1.65, 95% C.I:1.07, 2.54). On the other hand, young adults (18 to 30-year-old) had lower risk of developing HAI (ARR = 0.54 95% C.I: 0.32,0.93) Likewise, among non-surgical care groups, the risk of HAI was found to be high in patients with chest tube (ARR = 4.14, 95% C.I: 2.30,7.46), on mechanical ventilation (ARR = 1.99, 95% C.I: 1.06,3.74) and with underlying disease (ARR = 2.01, 95% C.I: 1.33,3.04). Furthermore, hospital aquired infection at the hosoital was associated with prolonged hospital stay [6.3 more days, 95% C.I: (5.16,7.48), t = 0.000] and increased in hospital mortality (AOR, 2.23, 95% CI:1.15,4.29).

Conclusion

This study revealed high burden and poor discharge outcomes of healthcare associated infection at Jimma University Medical Centre. There is a difference in risk factors between patients with and without surgery. Hence, any effort to control the observed high burden of HAI at the hospital should consider these differences for better positive out put.

Electronic supplementary material

The online version of this article (10.1186/s13756-017-0298-5) contains supplementary material, which is available to authorized users.

Health care workers' knowledge, attitudes and practices on tuberculosis infection control, Nepal

Background

Infection control remains a key challenge for Tuberculosis (TB) control program with an increased risk of TB transmission among health care workers (HCWs), especially in settings with inadequate TB infection control measures. Poor knowledge among HCWs and inadequate infection control practices may lead to the increased risk of nosocomial TB transmission.

Methods

An institution-based cross-sectional survey was conducted in 28 health facilities providing TB services in the Kathmandu Valley, Nepal. A total of 190 HCWs were assessed for the knowledge, attitudes and practices on TB infection control using a structured questionnaire.

Results

The level of knowledge on TB infection control among almost half (45.8%) of the HCWs was poor, and was much poorer among administration and lower level staff. The knowledge level was significantly associated with educational status, and TB training and/or orientation received. The majority (73.2%) of HCWs had positive attitude towards TB infection control. Sixty-five percent of HCWs were found to be concerned about being infected with TB. Use of respirators among the HCWs was limited and triage of TB suspects was also lacking.

Conclusions

Overall knowledge and practices of HCWs on TB infection control were not satisfactory. Effective infection control measures including regular skill-based training and/or orientation for all categories of HCWs can improve infection control practices in health facilities.

"Who has to do it at the end of the day? Programme officials or hospital authorities?" Airborne infection control at drug resistant tuberculosis (DR-TB) centres of Karnataka, India: a mixed-methods study

Background

Drug resistant tuberculosis (DR-TB) centers admit patients with DR-TB for initiation of treatment and thereby concentrate the patients under one setting. It becomes imperative to assess the compliance of DR-TB centres to national airborne infection control (AIC) guidelines and explore the provider perspectives into reasons for unsatisfactory compliance.

Methods

This mixed methods study (triangulation design) was carried out across all the six DR-TB centers of Karnataka state, India, between November 2016 and April 2017. Non-participant observation using a structured format was carried out at the DR-TB wards (n = 6), outpatient departments (n = 6), patient waiting areas outside outpatient departments (n = 6) and culture and drug susceptibility testing laboratories (n = 3). Structured interviews of admitted patients (n = 30) were done to assess the knowledge on cough hygiene and sputum disposal. Key informant interviews (KIIs) of health care providers (n = 20) were done. Manual descriptive content analysis was done to analyse the transcripts of KIIs.

Results

The findings related to compliance in non-participant observation were corroborated by KIIs. All the laboratories were consistently implementing the AIC guidelines. Compliance to hand hygiene, wet mopping and ventilation measures were satisfactory in four or more DR-TB wards. The non-availability of N95 masks in wards as well as outpatient departments was staggering. Sputum disposal without prior disinfection and the lack of display materials on cough hygiene and patient education was common. Patient fast tracking in outpatient department waiting areas and visitor restrictions in wards were lacking. Trainings on AIC measures were uncommon. About half and one-third of patients admitted had satisfactory knowledge regarding sputum disposal and situations demanding mask respectively. The reasons for unsatisfactory compliance to AIC guidelines were poor coordination between programme and hospital authorities leading to lack of ownership; ineffective or non-existent infection control committees; vacant posts of medical officers; and attitudes of health care delivery staff.

Conclusion

Compliance with AIC guidelines in DR-TB centers of Karnataka was sub-optimal. The reasons identified require urgent attention of the programme managers and hospital authorities.

Electronic supplementary material

The online version of this article (10.1186/s13756-017-0270-4) contains supplementary material, which is available to authorized users.

Drivers of Tuberculosis Transmission

Measuring tuberculosis transmission is exceedingly difficult, given the remarkable variability in the timing of clinical disease after Mycobacterium tuberculosis infection; incident disease can result from either a recent (ie, weeks to months) or a remote (ie, several years to decades) infection event. Although we cannot identify with certainty the timing and location of tuberculosis transmission for individuals, approaches for estimating the individual probability of recent transmission and for estimating the fraction of tuberculosis cases due to recent transmission in populations have been developed. Data used to estimate the probable burden of recent transmission include tuberculosis case notifications in young children and trends in tuberculin skin test and interferon γ-release assays. More recently, M. tuberculosis whole-genome sequencing has been used to estimate population levels of recent transmission, identify the distribution of specific strains within communities, and decipher chains of transmission among culture-positive tuberculosis cases. The factors that drive the transmission of tuberculosis in communities depend on the burden of prevalent tuberculosis; the ways in which individuals live, work, and interact (eg, congregate settings); and the capacity of healthcare and public health systems to identify and effectively treat individuals with infectious forms of tuberculosis. Here we provide an overview of these factors, describe tools for measurement of ongoing transmission, and highlight knowledge gaps that must be addressed.

Infection control, genetic assessment of drug resistance and drug susceptibility testing in the current management of multidrug/extensively-resistant tuberculosis (M/XDR-TB) in Europe: A tuberculosis network European Trialsgroup (TBNET) study

AIM

Europe has the highest documented caseload and greatest increase in multidrug and extensively drug-resistant tuberculosis (M/XDR-TB) of all World Health Organization (WHO) regions. This survey examines how recommendations for M/XDR-TB management are being implemented.

METHODS

TBNET is a pan-European clinical research collaboration for tuberculosis. An email survey of TBNET members collected data in relation to infection control, access to molecular tests and basic microbiology with drug sensitivity testing.

RESULTS

68/105 responses gave valid information and were from countries within the WHO European Region. Inpatient beds matched demand, but single rooms with negative pressure were only available in low incidence countries; ultraviolet decontamination was used in 5 sites, all with >10 patients with M/XDR-TB per year. Molecular tests for mutations associated with rifampicin resistance were widely available (88%), even in lower income and especially in high incidence countries. Molecular tests for other first line and second line drugs were less accessible (76 and 52% respectively). A third of physicians considered that drug susceptibility results were delayed by > 2 months.

CONCLUSION

Infection control for inpatients with M/XDR-TB remains a problem in high incidence countries. Rifampicin resistance is readily detected, but tests to plan regimens tailored to the drug susceptibilities of the strain of Mycobacterium tuberculosis are significantly delayed, allowing for further drug resistance to develop.

Epidemiological trends and outcomes of extensively drug-resistant tuberculosis in Shandong, China

BACKGROUND

Extensively Drug-Resistant (XDR) Tuberculosis (TB) has posed a great threat to global health and finance systems, especially for developing countries with high TB and Multidrug-Resistant (MDR) TB burden.

METHODS

We retrospectively analyzed HIV-uninfected TB case confirmed and treated in Shandong Provincial Chest Hospital (SPCH) between January 2008 and December 2015. Unique characteristics of XDR-TB were identified; its longitudinal changes and survival were analyzed.

RESULTS

Between January 2008 and December 2015, a total of 144 cases were confirmed to be XDR-TB (2.5% of 5663 culture-confirmed TB cases; 27.9% of 516 MDR-TB cases). The proportion of XDR TB cases among MDR-TB cases has increased from 26.5% in 2008 to 44.5% in 2014 (Chi-Square test for trends: P < 0.01). Among the 144 XDR-TB cases, 21 patients (14.6%) had treatment success, 123 (85.1%) had poor treatment outcomes. Mortality was higher among XDR-TB cases than among MDR TB cases (8.3% vs. 3.8%, P = 0.033) and drug-susceptible TB cases (8.3% vs. 2.1%, P < 0.01).

CONCLUSIONS

XDR-TB cases comprise a substantial and increasing fraction of MDR-TB cases, causing poor treatment outcomes and high mortalities. Early drug susceptibility testing, adequate TB treatment and efficient infection control must be in place in future TB control strategies.

Towards understanding the drivers of policy change: a case study of infection control policies for multi-drug resistant tuberculosis in South Africa

Background

Explaining policy change is one of the central tasks of contemporary policy analysis. In this article, we examine the changes in infection control policies for multi-drug resistant tuberculosis (MDR-TB) in South Africa from the time the country made the transition to democracy in 1994, until 2015. We focus on MDR-TB infection control and refer to decentralised management as a form of infection control. Using Kingdon’s theoretical framework of policy streams, we explore the temporal ordering of policy framework changes. We also consider the role of research in motivating policy changes.

Methods

Policy documents addressing MDR-TB in South Africa over the period 1994 to 2014 were extracted. Literature on MDR-TB infection control in South Africa was extracted from PubMed using key search terms. The documents were analysed to identify the changes that occurred and the factors driving them.

Results

During the period under study, five different policy frameworks were implemented. The policies were meant to address the overwhelming challenge of MDR-TB in South Africa, contextualised by high prevalence of HIV infection, that threatened to undermine public health programmes and the success of antiretroviral therapy rollouts. Policy changes in MDR-TB infection control were supported by research evidence and driven by the high incidence and complexity of the disease, increasing levels of dissatisfaction among patients, challenges of physical, human and financial resources in public hospitals, and the ideologies of the political leadership. Activists and people living with HIV played an important role in highlighting the importance of MDR-TB as well as exerting pressure on policymakers, while the mass media drew public attention to infection control as both a cause of and a solution to MDR-TB.

Conclusion

The critical factors for policy change for infection control of MDR-TB in South Africa were rooted in the socioeconomic and political environment, were supported by extensive research, and can be framed using Kingdon’s policy streams approach as an interplay of the problem of the disease, political forces that prevailed and alternative proposals.