A tuberculin skin test survey among healthcare workers in two public tertiary care hospitals in Bangladesh

Prevalence and exposure variables of latent infection by mycobacterium tuberculosis in healthcare workers

OBJECTIVES

To identify in the scientific literature the prevalence, diagnostic methods, and exposure variables of latent infection by Mycobacterium tuberculosis in healthcare workers.

METHODS

An integrative review of the scientific literature based on the following review question: What are the available scientific evidence in the literature that address the prevalence of latent infection by Mycobacterium tuberculosis in healthcare workers and its association with possible risk factors among these workers?

RESULTS

Being a physician or nurse, being older, and being male were generally associated with higher prevalences. The study also showed that interferon-gamma release assays were more commonly used as a diagnostic method compared to skin tests.

CONCLUSIONS

More studies are needed regarding the epidemiology of latent infection by Mycobacterium tuberculosis in the context of healthcare workers, aiming for higher impact actions that contribute to the reduction of tuberculosis worldwide.

Performance of Current Diagnostic Tools in Detecting Latent Tuberculosis Among Healthcare Workers: A Systematic Review

Testing for latent tuberculosis infection is essential for diagnosing Mycobacterium tuberculosis infections in asymptomatic individuals. Preventing the transition of latent to active tuberculosis is imperative, especially in high-risk populations such as healthcare workers. Interferon-gamma release assays (IGRAs) and the Mantoux/tuberculin skin test (TST) are two examples of diagnostic instruments utilized for detection. Systematic evaluations of the characteristics of widely available tests are very helpful for diagnosticians because these tests might not be easily accessible in situations with limited resources. This systematic review aims to evaluate and compare the diagnostic accuracy of tests for latent tuberculosis infection in healthcare workers. The review, conducted from 2013 to 2024, aimed to identify studies on "Latent Tuberculosis," "Healthcare workers," "Diagnostic modalities," "TST," "Interferon-gamma release assays," and "IGRA." The review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines and developed a data extraction toolkit. Three authors independently reviewed the literature, ensuring uniformity. Discrepancies were resolved through discussions and mediation until a consensus was reached. Statistical significance was defined as a p-value of 0.05 or lower. The review provides valuable insights into the diagnostic accuracy of these tests, particularly in high-risk populations. The TST had a sensitivity of 76.5% (confidence interval (CI) = 61.5-91.5%) and specificity of 77.2% (CI = 65-85%). Its positive predictive value (PPV) was 54.8% (CI = 45-65%), and the negative predictive value (NPV) was 88.5% (CI = 85-92%), with an odds ratio of 63.6 and an area under the curve (AUC) of 0.72. QuantiFERON-TB Gold In-Tube (QFT-GIT) showed a sensitivity of 68.35% (CI = 67.15-70.55%) and a specificity of 82.32% (CI = 72.32-97.47%). Its PPV was 56% (CI = 54-92%), and NPV was 92.7% (CI = 89-96%), with an odds ratio of 357.9 and an AUC of 0.767. QuantiFERON-TB Gold Plus (QFT-Plus) had a sensitivity of 85% (CI = 78.9-91.1%) and a specificity of 73.52% (CI = 35.71-93.75%). Its PPV was 59.2% (CI = 39.3-78.2%), and NPV was 95% (CI = 91.2-98%), with an odds ratio of 125.39 and an AUC of 0.89. T-SPOT.TB showed a sensitivity of 92% (CI = 87-97%) and a specificity of 95.7% (CI = 94-98%). Its PPV was 86.8% (CI = 85-95.8%), and NPV was 95.8% (CI = 92.5-96.7%), with an odds ratio of 1.03 and an AUC of 0.7. CLIA-IGRA had a sensitivity of 100% (CI = 99.9-100%) and a specificity of 95.57% (CI = 95.57-100%). Its PPV was 96.8% (CI = 96.8-100%), and NPV was 99.8% (CI = 99.8-100%), with an odds ratio of 1509 and an AUC of 0.97. HBHA-induced IGRA showed a sensitivity of 86.4% (CI = 71.1-97.3%) and a specificity of 82.5% (CI = 66.4-92.6%). Its PPV was 86.8% (CI = 66.7-95.3%), and NPV was 86.4% (CI = 57.8-95.7%), with an odds ratio of 6.18 and an AUC of 0.886. There are specific benefits and drawbacks of each diagnostic test for latent tuberculosis infection. With its exceptional sensitivity and specificity, the CLIA-IGRA test is a top choice for a precise diagnosis of tuberculosis. Practical factors such as availability and cost, however, might prevent its widespread usage. Both the QuantiFERON and TST are still useful tools, especially when used in certain populations or situations when their performance characteristics meet clinical requirements.

Prevalence and incidence of tuberculosis infection among healthcare workers in chest diseases hospitals, Bangladesh: Putting infection control into context

BACKGROUND

Healthcare workers (HCWs) are at increased risk of tuberculosis infection (TBI). We estimated the prevalence and incidence of TBI and risk factors among HCWs in Bangladeshi hospitals to target TB infection prevention and control (IPC) interventions.

METHODS

During 2013-2016, we conducted a longitudinal study among HCWs in four chest disease hospitals. At baseline, we administered a questionnaire on sociodemographic and occupational factors for TB, tuberculin skin tests (TST) in all hospitals, and QuantiFERON ®-TB Gold in-Tube (QFT-GIT) tests in one hospital. We assessed factors associated with baseline TST positivity (induration ≥10mm), TST conversion (induration increase ≥10mm from baseline), baseline QFT-GIT positivity (interferon-gamma ≥0.35 IU/mL), and QFT-GIT conversion (interferon-gamma <0.35 IU/mL to ≥0.35 IU/mL). We included factors with a biologically plausible relationship with TBI identified in prior studies or having an association (p = <0.20) in the bivariate analyses with TST positivity or QFT-GIT positivity in multivariable generalized linear models. The Kaplan-Meier was used to estimate the cumulative TBI incidence rate per 100 person-years.

RESULTS

Of the 758 HCWs invited, 732 (97%) consented to participate and 731 completed the one-step TST, 40% had a positive TST result, and 48% had a positive QFT-GIT result. In multivariable models, HCWs years of service 11-20 years had 2.1 (95% CI: 1.5-3.0) times higher odds of being TST-positive and 1.6 (95% CI 1.1-2.5) times higher odds of QFT-GIT-positivity at baseline compared with those working ≤10 years. HCWs working 11-20 years in pulmonary TB ward had 2.0 (95% CI: 1.4-2.9) times higher odds of TST positivity, and those >20 years had 2.5 (95% CI: 1.3-4.9) times higher odds of QFT-GIT-positivity at baseline compared with those working <10 years. TBI incidence was 4.8/100 person-years by TST and 4.2/100 person-years by QFT-GIT. Females had 8.5 (95% CI: 1.5-49.5) times higher odds of TST conversion than males.

CONCLUSIONS

Prevalent TST and QFT-GIT positivity was associated with an increased number of years working as a healthcare worker and in pulmonary TB wards. The incidence of TBI among HCWs suggests ongoing TB exposure in these facilities and an urgent need for improved TB IPC in chest disease hospitals in Bangladesh.

Preparedness of tertiary care hospitals to implement the national TB infection prevention and control guidelines in Bangladesh: A qualitative exploration

In high tuberculosis (TB) burden countries, health settings, including non-designated TB hospitals, host many patients with pulmonary TB. Bangladesh's National TB Control Program aims to strengthen TB infection prevention and control (IPC) in health settings. However, there has been no published literature to date that assessed the preparedness of hospitals to comply with the recommendations. To address this gap, our study examined healthcare workers knowledge and attitudes towards TB IPC guidelines and their perceptions regarding the hospitals' preparedness in Bangladesh. Between January to December 2019, we conducted 16 key-informant interviews and four focus group discussions with healthcare workers from two public tertiary care hospitals. In addition, we undertook a review of 13 documents [i.e., hospital policy, annual report, staff list, published manuscript]. Our findings showed that healthcare workers acknowledged the TB risk and were willing to implement the TB IPC measures but identified key barriers impacting implementation. Gaps were identified in: policy (no TB policy or guidelines in the hospital), health systems (healthcare workers were unaware of the guidelines, lack of TB IPC program, training and education, absence of healthcare-associated TB infection surveillance, low priority of TB IPC, no TB IPC monitoring and feedback, high patient load and bed occupancy, and limited supply of IPC resources) and behavioural factors (risk perception, compliance, and self and social stigma). The additional service-level gap was the lack of electronic medical record systems. These findings highlighted that while there is a demand amongst healthcare workers to implement TB IPC measures, the public tertiary care hospitals have got key issues to address. Therefore, the National TB Control Program may consider these gaps, provide TB IPC guidelines to these hospitals, assist them in developing hospital-level IPC manual, provide training, and coordinate with the ministry of health to allocate separate budget, staffing, and IPC resources to implement the control measures successfully.

Monocyte-related gene biomarkers for latent and active tuberculosis

Monocytes are closely associated with tuberculosis (TB). Latent tuberculosis in some patients gradually develops into its active state. This study aimed to investigate the role of hub monocyte-associated genes in distinguishing latent TB infection (LTBI) from active TB. The gene expression profiles of 15 peripheral blood mononuclear cells (PBMCs) samples were downloaded from the gene expression omnibus (GEO) database, GSE54992. The monocyte abundance was high in active TB as evaluated by the Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) algorithm. The limma test and correlation analysis documented 165 differentially expressed monocyte-related genes (DEMonRGs) between latent TB and active TB. Functional annotation and enrichment analyses of the DEMonRGs using the database for annotation, visualization, and integration discovery (DAVID) tools showed enrichment of inflammatory response mechanisms and immune-related pathways. A protein-protein interaction network was constructed with a node degree ≥10. The expression levels of these hub DEMonRGs (SERPINA1, FUCA2, and HP) were evaluated and verified using several independent datasets and clinical settings. Finally, a single sample scoring method was used to establish a gene signature for the three DEMonRGs, distinguishing active TB from latent TB. The findings of the present study provide a better understanding of monocyte-related molecular fundamentals in TB progression and contribute to the identification of new potential biomarkers for the diagnosis of active TB.

Implementation status of national tuberculosis infection control guidelines in Bangladeshi hospitals

In response to the World Health Organization (WHO) recommendation to reduce healthcare workers’ (HCWs’) exposure to tuberculosis (TB) in health settings, congregate settings, and households, the national TB control program of Bangladesh developed guidelines for TB infection prevention and control (IPC) in 2011. This study aimed to assess the implementation of the TB IPC healthcare measures in health settings in Bangladesh. Between February and June 2018, we conducted a mixed-method study at 11 health settings. The team conducted 59 key-informant interviews with HCWs to understand the status of and barriers impeding the implementation of the TB IPC guidelines. The team also performed a facility assessment survey and examined TB IPC practices. Most HCWs were unaware of the national TB IPC guidelines. There were no TB IPC plans or committees at the health settings. Further, a presumptive pulmonary TB patient triage checklist was absent in all health settings. However, during facility assessment, we observed patient triaging and separation in the TB specialty hospitals. Routine cough-etiquette advice was provided to the TB patients mentioned during the key-informant interviews, which was consistent with findings from the survey. This study identified poor implementation of TB IPC measures in health settings. Limited knowledge of the guidelines resulted in poor implementation of the recommendations. Interventions focusing on the dissemination of the TB IPC guidelines to HCWs along with regular training may improve compliance. Such initiatives should be taken by hospital senior leadership as well as national policy makers.