Risk of tuberculosis among healthcare workers in an intermediate-burden country: a nationwide population study

The Risk of Latent Tuberculosis Infection Among Healthcare Workers at a General Hospital in Bisha, the Kingdom of Saudi Arabia

Background and objective Tuberculosis (TB) is a global health issue, often preceded by a latent tuberculosis infection (LTBI) in individuals. Significant global and local efforts have recently been directed toward this infection, focusing on TB control and eradication. This study aimed to assess the magnitude of LTBI among healthcare workers (HCWs) in the Kingdom of Saudi Arabia, by evaluating its prevalence and associated risk factors. Methods An analytical cross-sectional study was conducted among HCWs at the King Abdullah Hospital (KAH), from January to August 2018, by using two surveys: the first one involved data related to HCW demographics and the tuberculin skin test (TST) readings, and the second involved a questionnaire that assessed LTBI risk factors. Results Out of the total 561 HCWs who participated in the study, 66 had an induration reading of more than 10 mm in TST. Many factors were associated with LTBI cases, but multivariate analysis showed that age, gender, and nationality were statistically significant risk factors. Conclusion Given the nature of their work, HCWs are at a greater risk of TB and LTBI. At the same time, HCWs are uniquely positioned to play a crucial role in halting the spread of TB. Gaps in preventive measures may result in the increased spread of TB. Our study assessed risk factors associated with the increased risk of LTBI and proposed possible ways of addressing them.

Progress on diagnosis and treatment of latent tuberculosis infection

One fourth of the global population has been infected with Mycobacterium tuberculosis, and about 5%-10% of the infected individuals with latent tuberculosis infection (LTBI) will convert to active tuberculosis (ATB). Correct diagnosis and treatment of LTBI are important in ending the tuberculosis epidemic. Current methods for diagnosing LTBI, such as tuberculin skin test (TST) and interferon-γ release assay (IGRA), have limitations. Some novel biomarkers, such as transcriptome derived host genes in peripheral blood cells, will help to distinguish LTBI from ATB. More emphasis should be placed on surveillance in high-risk groups, including patients with HIV infection, those using biological agents, organ transplant recipients and those in close contact with ATB patients. For those with LTBI, treatment should be based on the risk of progression to ATB and the potential benefit. Prophylactic LTBI regimens include isoniazid monotherapy for 6 or 9 months, rifampicin monotherapy for 4 months, weekly rifapentine plus isoniazid for 3 months (3HP regimen) and daily rifampicin plus isoniazid for 3 months (3HR regimen). The success of the one month rifapentine plus isoniazid daily regimen (1HP regimen) suggests the feasibility of an ultra-short treatment strategy although its efficacy needs further assessment. Prophylactic treatment of LTBI in close contact with MDR-TB patients is another challenge, and the regimens include new anti-tuberculosis drugs such as bedaquiline, delamanid, fluoroquinolone and their combinations, which should be carefully evaluated. This article summarizes the current status of diagnosis and treatment of LTBI and its future development direction.

Cohort Profile: Korean Tuberculosis and Post-Tuberculosis Cohort Constructed by Linking the Korean National Tuberculosis Surveillance System and National Health Information Database

We aimed to review the current data composition of the Korean Tuberculosis and Post-Tuberculosis Cohort, which was constructed by linking the Korean Tuberculosis Surveillance System (KNTSS; established and operated by the Korean Disease Control and Prevention Agency since 2000) and the National Health Information Database (NHID; established by the National Health Insurance Service in 2012). The following data were linked: KNTSS data pertaining to patients diagnosed with tuberculosis between 2011 and 2018, NHID data of patients with a history of tuberculosis and related diseases between 2006 and 2018, and data (obtained from the Statistics Korea database) on causes of death. Data from 300 117 tuberculosis patients (177 206 men and 122 911 women) were linked. The rate of treatment success for new cases was highest in 2015 (86.7%), with a gradual decrease thereafter. The treatment success rate for previously treated cases showed an increasing trend until 2014 (79.0%) and decreased thereafter. In total, 53 906 deaths were confirmed among tuberculosis patients included in the cohort. The Korean Tuberculosis and Post-Tuberculosis Cohort can be used to analyze different measurement variables in an integrated manner depending on the data source. Therefore, these cohort data can be used in future epidemiological studies and research on policy-effect analysis, treatment outcome analysis, and health-related behaviors such as treatment discontinuation.

Tuberculosis infection status and risk factors among health workers: an updated systematic review

Tuberculosis (TB) infection is a common occupational risk for health workers (HWs) and poses a threat to the patients under their care and to other HWs. Hence, the development of a prevention strategy is crucial. We conducted a study to understand the status and risk factors of TB infection among HWs. The existing literature was searched for all published reports from 1 August 2010 to 31 December 2018, related to TB among HWs according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The inclusion criteria were: (1) study participants working in a health care facility; (2) TB cases diagnosed by medical professionals; (3) original research articles; and (4) English reports in a peer-reviewed journal. We finally included 61 studies from 642 articles searched initially. The TB infection rate in HWs was higher than that of the general population. Based on 39 studies, the prevalence of TB in HWs (tuberculin skin test positive) was 29.94%. In contrast, the global burden of latent TB infection was 23.0% (95% uncertainty interval: 20.4%–26.4%) in 2014. The risk factors of TB among HWs were aging, long duration of employment, nursing professionals, lack of Bacillus Calmette-Guerin vaccination, and low body mass index. HWs have an increased risk for TB infection, which can cause secondary infections in patients or other HWs. An effective prevention strategy must be developed to enable early diagnosis and prompt treatment.

Work-Related Tuberculosis among Health Workers Employed in a Tertiary Hospital in Northeastern Thailand: A Report of Nine Cases

Between October 2016 and September 2018, fifteen health workers were diagnosed with tuberculosis (TB) at a tertiary hospital in northeastern Thailand. However, the cases could not be diagnosed as occupational TB according to international standards because of hospital limitations. The use of occupational epidemiological information provides a more effective work-related TB diagnosis. This study aims to provide a report of work-related TB using individual case investigation methods. We collected secondary data from the Occupational Health and Safety Office of the hospital in question, including baseline characteristics for the health workers, occupational history, source of TB infection and occupational exposure, and working environmental measurements. We found that nine of the fifteen cases were diagnosable as work-related TB due to two important factors: daily prolonged exposure time to an infected TB patient, and aerosol-generating procedures without adequate respiratory protection. The other six cases were not diagnosable as work-related TB because of inadequate evidence of activities related to the TB infection. The diagnosis of work-related TB thus requires occupational epidemiological information in order to complete the differentiation process.

Occupational health and safety hazards faced by healthcare professionals in Taiwan: A systematic review of risk factors and control strategies

Background

Healthcare professionals in Taiwan are exposed to a myriad of occupational health and safety hazards, including physical, biological, chemical, ergonomic, and psychosocial hazards. Healthcare professionals working in hospitals and healthcare facilities are more likely to be subjected to these hazards than their counterparts working in other areas.

Objectives

This review aims to assess current research literature regarding this situation with a view to informing policy makers and practitioners about the risks of exposure and offer evidence-based recommendations on how to eliminate or reduce such risks.

Methods

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses review strategy, we conducted a systematic review of studies related to occupational health and safety conducted between January 2000 and January 2019 using MEDLINE (Ovid), PubMed, PMC, TOXLINE, CINAHL, PLOS One, and Access Pharmacy databases.

Results

The review detected 490 studies addressing the issue of occupational health and safety hazards; of these, 30 articles were included in this systematic review. These articles reported a variety of exposures faced by healthcare professionals. This review also revealed a number of strategies that can be adopted to control, eliminate, or reduce hazards to healthcare professionals in Taiwan.

Conclusion

Hospitals and healthcare facilities have many unique occupational health and safety hazards that can potentially affect the health and performance of healthcare professionals. The impact of such hazards on healthcare professionals poses a serious public health issue in Taiwan; therefore, controlling, eliminating, or reducing exposure can contribute to a stronger healthcare workforce with great potential to improve patient care and the healthcare system in Taiwan. Eliminating or reducing hazards can best be achieved through engineering measures, administrative policy, and the use of personal protective equipment.

Implications

This review has research, policy, and practice implications and provides future students and researchers with information on systematic review methodologies based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses strategy. It also identifies occupational health and safety risks and provides insights and strategies to address them.

Isolation measures and protection awareness are significant for latent tuberculosis infection: a cross-sectional study based on T-SPOT.TB among health care workers in China

This study aimed to reveal the associated risk factors for latent tuberculosis infection (LTBI) detected by T-SPOT.TB assay among health care workers (HCWs) at different working locations or job categories in China. This cross-sectional study included 934 HCWs who underwent the T-SPOT.TB assay. Demographic and social characteristics of the participants, including age, sex, job categories, department/ward and duration of healthcare service, were recorded. Among 934 HCWs, 267 (28.5867%) were diagnosed as having LTBI with positive T-SPOT.TB assay. HCWs working in inpatient tuberculosis (TB) (odds ratio (OR) 2.917; 95% confidence interval (CI) 1.852–4.596; P < 0.001) and respiratory wards (OR 1.840; 95% CI 1.124–3.011; P = 0.015), and with longer duration of healthcare service (OR 1.048; 95% CI 1.016–1.080; P = 0.003) were risk factors for positive T-SPOT.TB result. Furthermore, longer working duration increased the positive rate of T-SPOT.TB results for physicians and nurses, and physicians had higher risks than nurses for the same working duration. Inpatient TB and respiratory wards were high-risk working locations for HCWs with LTBI, and longer duration of healthcare service also increased the risk of LTBI among HCWs. A complete strategy for TB infection control and protection awareness among HCWs should be enhanced.

The Prevalence and Demographic Risk Factors for Latent Tuberculosis Infection (LTBI) Among Healthcare Workers in Semarang, Indonesia

Purpose

To determine the prevalence and demographic risk factors for latent tuberculosis infection (LTBI) among healthcare workers in Semarang, Indonesia.

Methods

A cross-sectional study involving 195 healthcare workers from 34 primary health centers was conducted from August to October 2019. The relationship between independent variables and dependent variables was analyzed using a multivariable logistic regression analysis.

Results

The prevalence of LTBI among healthcare workers in this study was 23.6%. Comorbidities were the only risk factor for LTBI identified among other risk factors (OR=3.39, 95% CI: 0.99–11.62, p=0.04). Other demographic factors such as age (OR=0.93, 95% CI: 0.45–1.92, p=0.839), gender (OR=0.79, 95% CI: 0.23–2.72, p=0.708, smoking habits (OR=2.54, 95% CI: 0.52–12.38, p=0.247), and length of work (OR=1.43, 95% CI: 0.70–2.91, p=0.331) were not significant risk factors for LTBI.

Conclusion

Healthcare workers suffering from comorbidity have a high risk for tuberculosis infection, and should not work in areas where they would be exposed to patients with tuberculosis. Healthcare workers need to apply occupational safety standards during contact with TB patients or specimens to minimize the disease transmission.

Risk factors of tuberculosis infection among health care workers: A meta-analysis

BACKGROUNDS

Health care workers (HCWs) are globally known to have high risk of tuberculosis (TB) infection while risk factors of TB infections among HCWs are still inconclusive.

OBJECTIVES

To perform a meta-analysis in effort to identify risk factors of TB infection among HCWs.

METHODS

A meta-analysis was conducted between February and July 2019. Papers were searched in Pubmed, Embase, Cochrane, and Web of science and information of interest were extracted. The correlation and effect estimation were analyzed using random or fixed effect model.

RESULTS

A total of 12 studies consisting of 2871 cases and 15,673 controls were included and six risk factors were available for meta-analysis. Cumulative calculation found that age, working duration, and types of job were significant risk factor of TB infection while gender, active TB contact, and types of workplace were not associated significantly with TB infection among HCWs. Our pooled data revealed that decreased risk of TB infection was observed in age less than 30 years (age < 30 years vs. age ≥ 30 years) and working duration less than five years (working duration < 5 years vs. ≥5 years). Being more than 40 years, working more than 10 years, and being physicians increased the risk of TB infection significantly compared to age ≤40 years, working duration ≤10 years, and other job types, respectively.

CONCLUSIONS

Our meta-analysis has identified the significant risk factors of TB infection among HCWs. Our results may be useful for establishing future TB prevention program among HCWs.

Difficulties in tuberculosis infection control in a general hospital of Vietnam: a knowledge, attitude, and practice survey and screening for latent tuberculosis infection among health professionals

BACKGROUND

In Vietnam, a country with a high tuberculosis (TB) burden, health professionals in both TB-specialized and non-TB-specialized general hospitals have a high risk of acquiring TB. The aims of the present study were to clarify the difficulties in TB infection control at non-TB specialized hospitals and whether any associated risks of latent TB infection exist among health professionals in Vietnam.

METHODS

We conducted a cross-sectional study in a national tertiary and general hospital of Hanoi, Vietnam. Participants were health professionals, including physicians, nurses, and other health professionals. We assessed difficulties in TB infection control by conducting a knowledge, attitude, and practice (KAP) survey. We also collected data on the results of tuberculin skin tests (TSTs) conducted during health check-ups for hospital staff to determine whether health professionals had latent TB infection or TB disease. KAP scores were compared among health professional groups (physicians vs. nurses vs. other health professionals). Factors influencing knowledge scores were evaluated using multiple regression analysis.

RESULTS

A total 440 health professionals at the study site participated in the KAP survey, and we collected the results of TSTs from a total of 299 health professionals. We observed a high prevalence of latent TB infection (74.2%), especially among participants in the emergency department. Although participants had high KAP scores, some topics were less understood, such as symptoms and risks of TB, proper use of protective equipment such as N95 respirators, and preventing transmission by patients with confirmed or suspected TB. Factors influencing knowledge scores associated with TB were age, a belief that TB is the most important infectious disease, being a medical professional, having previously attended workshops or seminars, and knowing that Vietnam has a high burden of TB.

CONCLUSION

In a non-TB specialized hospital of Vietnam, we observed a risk of TB infection among health professionals and difficulties in properly controlling TB infection. Early awareness regarding patients with suspected TB, to apply proper measures and prevent transmission, and education regarding obtaining updated knowledge through scientific information are crucial to enhancing TB infection control in general hospitals of Vietnam.

Antibodies and tuberculosis: finally coming of age?

Are antibodies important for protection against tuberculosis? The jury has been out for more than 100 years. B cell depletion in experimental Mycobacterium tuberculosis infection failed to identify a major role for these cells in immunity to tuberculosis. However, recent identification of naturally occurring antibodies in humans that are protective during M. tuberculosis infection has reignited the debate. Here, we discuss the evidence for a protective role for antibodies in tuberculosis and consider the feasibility of designing novel tuberculosis vaccines targeting humoral immunity.

Registered nurses are at increased risk of hospitalization for infectious diseases and perinatal complications: A population-based observational study

Background

Nursing staff spend long periods in high-risk working environments.

Objective

The purpose of this study was to compare the hospitalization risk between nursing staff and the general population.

Design

This study adopted a retrospective observational design.

Setting

Data from the Taiwan National Health Insurance Research Database from 2011 to 2013 were analyzed.

Method

The standardized hospitalization ratio model was used to analyze the relative risk of hospitalization for various diseases between nursing staff and the general population.

Results

A total of 33,267 numbers of nursing staff in Taiwan were hospitalized, an overall crude hospitalization rate of 21.5%. After controlling for gender, calendar year, and age of nursing staff, the standardized hospitalization ratio of female nursing staff was significantly higher compared to the general population for infectious and parasitic diseases (SHR = 121.05, 95% CI = 112.66–129.89), diseases of the respiratory system (SHR = 105.12, 95% CI = 100.60–109.80), complications of pregnancy, childbirth, and the puerperium (SHR = 102.59, 95% CI = 100.85–104.35), and diseases of the skin and subcutaneous tissue (SHR = 109.71, 95% CI = 101.10–118.86).

Conclusions

Nursing staff have a significantly higher hospitalization risk compared to the general population for infectious and parasitic diseases, diseases of the respiratory system, complications of pregnancy, childbirth, and puerperium, and diseases of the skin and subcutaneous tissue. This may be associated with the job characteristics and environment of nursing staff.

Utilization of Chinese medicine for respiratory discomforts by patients with a medical history of tuberculosis in Taiwan

Background

Tuberculosis (TB) is one of the world’s major communicable infectious diseases, and it still imposes a great health burden in developing countries. The development of drug-resistant TB during the treatment increases the treatment complexity, and the long-term pulmonary complications after completing treatment raise the epidemic health burden. This study intended to investigate the utilization of Chinese medicine (CM) for respiratory symptoms by patients with a medical history of TB in Taiwan.

Methods

We analyzed a cohort of one million individuals who were randomly selected from the National Health Insurance Research Database in Taiwan. The inclusion criteria of patients (n = 7905) with history of TB (ICD-9-CM codes 010–018 and A02) were: (1) TB diagnosed between January 1, 1997 and December 31, 2010 (2) 18 years old or over (3) Clinical records for at least 2 months with complete demographic information (4) Record of treatment with first-line TB medication prescriptions. CM users for conditions other than respiratory discomforts (n = 3980) were excluded. Finally, a total of 3925 TB patients were categorized as: CM users for respiratory discomforts (n = 2051) and non-CM users (n = 1874).

Results

Among the 3925 subjects, 2051 (52.25%) were CM users, and 1874 (44.753%) were non-CM users. Female patients and those who were younger (18–39 y/o) and who lived in urbanized areas relatively tended to be CM users (p < .0001). Most of the CM users (1944, 94.78%) received Chinese medicines. The most commonly prescribed herbal formulas and single herbs were Xiao-Qing-Long-Tang and Radix Platycodonis (Jie-Geng), respectively. The core pattern of Chinese medicines for TB patients consisted of Ma-Xing-Gan-Shi-Tang, Bulbus Fritillariae Thunbergii (Bei-Mu), Radix Platycodonis (Jie-Geng) and Semen Armeniacae (Xing-Ren).

Conclusions

The use of CM is popular among patients with a medical history of TB complicated with long-term respiratory discomforts in Taiwan. Further pharmacological investigations and clinical trials are required.

Preventive therapy for tuberculosis in rheumatological patients undergoing therapy with biological drugs

INTRODUCTION

Latent tuberculosis infection (LTBI) accounts for almost a quarter of the world population, and, in 5-10% of the subjects with impaired immune-response against M. tuberculosis growth, it may progress to active tuberculosis (TB). In this review, we focus on the need to propose a screening for LTBI including preventive therapy offer in rheumatic patients undergoing therapy with biological drugs. Areas covered: We report on evidence that biologics are associated with an increased risk of active TB reactivation. This effect seems to be mainly limited to treatment with anti-tumor necrosis factor (TNF) agents, while non-anti-TNF-targeted biologics are not likely associated to any increased risk. We introduce the concept that the patients' coexisting host-related risk factors, such as comorbidities, are crucial to identify those at higher risk to reactivate TB. We report that preventive TB therapy is well tolerated in patients treated with biological drugs. Expert commentary: Availability of non-anti-TNF targeted biologics, that are not associated with an increased risk of TB reactivation, offers a great opportunity to tailor a therapeutic intervention at low/absent TB risk. After proper LTBI screening investigations, preventive TB therapy has been demonstrated to be effective and well-tolerated to reduce the risk of TB reactivation in rheumatic patients requiring biological drugs.

Risk of Tuberculosis Infection and Disease for Health Care Workers: An Updated Meta-Analysis

Background

Tuberculosis (TB) remains a major challenge to global health. Healthcare workers (HCWs) appear to be at increased risk of TB compared with the general population, despite efforts to scale up infection control and reduce nosocomial TB transmission. This review aims to provide an updated estimate of the occupational risk of latent TB infection (LTBI) and active TB among HCWs compared with the general population.

Methods

A systematic review was performed to identify studies published over the last 10 years reporting TB prevalence or incidence among HCWs and a control group. Pooled effect estimates were calculated to determine the risk of infection.

Results

Twenty-one studies met the inclusion criteria, providing data on 30961 HCWs across 16 countries. Prevalence of LTBI among HCWs was 37%, and mean incidence rate of active TB was 97/100000 per year. Compared with the general population, the risk of LTBI was greater for HCWs (odds ratio [OR], 2.27; 95% confidence interval [CI], 1.61–3.20), and the incidence rate ratio for active TB was 2.94 (95% CI, 1.67–5.19). Comparing tuberculin skin test and interferon-gamma release assay, OR for LTBI was found to be 1.72 and 5.61, respectively.

Conclusions

The overall risk of both LTBI and TB to HCWs continues to be significantly higher than that of the general population, consistent with previous findings. This study highlights the continuing need for improvements in infection control and HCW screening programs.

Prevalence and risk factors for latent tuberculosis infection among healthcare workers in Nampula Central Hospital, Mozambique

BACKGROUND

Healthcare workers in high tuberculosis burdened countries are occupationally exposed to the tuberculosis disease with uncomplicated and complicated tuberculosis on the increase among them. Most of them acquire Mycobacterium tuberculosis but do not progress to the active disease - latent tuberculosis infection. The objective of this study was to assess the prevalence and risk factors associated with latent tuberculosis infection among healthcare workers in Nampula Central Hospital, Mozambique.

METHODS

This cross-sectional study of healthcare workers was conducted between 2014 and 2015. Participants (n = 209) were administered a questionnaire on demographics and occupational tuberculosis exposure and had a tuberculin skin test administered. Multivariate linear and logistic regression tested for associations between independent variables and dependent outcomes (tuberculin skin test induration and latent tuberculosis infection status).

RESULTS

The prevalence of latent tuberculosis infection was 34.4%. Latent tuberculosis infection was highest in those working for more than eight years (39.3%), those who had no BCG vaccination (39.6%) and were immunocompromised (78.1%). Being immunocompromised was significantly associated with latent tuberculosis infection (OR 5.97 [95% CI 1.89; 18.87]). Positive but non-significant associations occurred with working in the medical domain (OR 1.02 [95% CI 0.17; 6.37]), length of employment > eight years (OR 1.97 [95% CI 0.70; 5.53]) and occupational contact with tuberculosis patients (OR 1.24 [95% CI 0.47; 3.27]).

CONCLUSIONS

Personal and occupational factors were positively associated with latent tuberculosis infection among healthcare workers in Mozambique.

Latently and uninfected healthcare workers exposed to TB make protective antibodies against Mycobacterium tuberculosis

The role of Igs in natural protection against infection by Mycobacterium tuberculosis (Mtb), the causative agent of TB, is controversial. Although passive immunization with mAbs generated against mycobacterial antigens has shown protective efficacy in murine models of infection, studies in B cell-depleted animals only showed modest phenotypes. We do not know if humans make protective antibody responses. Here, we investigated whether healthcare workers in a Beijing TB hospital-who, although exposed to suprainfectious doses of pathogenic Mtb, remain healthy-make antibody responses that are effective in protecting against infection by Mtb. We tested antibodies isolated from 48 healthcare workers and compared these with 12 patients with active TB. We found that antibodies from 7 of 48 healthcare workers but none from active TB patients showed moderate protection against Mtb in an aerosol mouse challenge model. Intriguingly, three of seven healthcare workers who made protective antibody responses had no evidence of prior TB infection by IFN-γ release assay. There was also good correlation between protection observed in vivo and neutralization of Mtb in an in vitro human whole-blood assay. Antibodies mediating protection were directed against the surface of Mtb and depended on both immune complexes and CD4+ T cells for efficacy. Our results indicate that certain individuals make protective antibodies against Mtb and challenge paradigms about the nature of an effective immune response to TB.

Use of low-dose computed tomography to assess pulmonary tuberculosis among healthcare workers in a tuberculosis hospital

Background

According to the World Health Organization, China is one of 22 countries with serious tuberculosis (TB) infections and one of the 27 countries with serious multidrug-resistant TB strains. Despite the decline of tuberculosis in the overall population, healthcare workers (HCWs) are still at a high risk of infection. Compared with high-income countries, the TB prevalence among HCWs is higher in low- and middle-income countries. Low-dose computed tomography (LDCT) is becoming more popular due to its superior sensitivity and lower radiation dose. However, there have been no reports about active pulmonary tuberculosis (PTB) among HCWs as assessed with LDCT. The purposes of this study were to examine PTB statuses in HCWs in hospitals specializing in TB treatment and explore the significance of the application of LDCT to these workers.

Methods

This study retrospectively analysed the physical examination data of healthcare workers in the Beijing Chest Hospital from September 2012 to December 2015. Low-dose lung CT examinations were performed in all cases. The comparisons between active and inactive PTB according to the CT findings were made using the Pearson chi-square test or the Fisher’s exact test. Comparisons between the incidences of active PTB in high-risk areas and non-high-risk areas were performed using the Pearson chi-square test. Analyses of active PTB were performed according to different ages, numbers of years on the job, and the risks of the working areas. Active PTB as diagnosed by the LDCT examinations alone was compared with the final comprehensive diagnoses, and the sensitivity and positive predictive value were calculated.

Results

A total of 1 012 participants were included in this study. During the 4-year period of medical examinations, active PTB was found in 19 cases, and inactive PTB was found in 109 cases. The prevalence of active PTB in the participants was 1.24%, 0.67%, 0.81%, and 0.53% for years 2012 to 2015. The corresponding incidences of active PTB among the tuberculosis hospital participants were 0.86%, 0.41%, 0.54%, and 0.26%. Most HCWs with active TB (78.9%, 15/19) worked in the high-risk areas of the hospital. There was a significant difference in the incidences of active PTB between the HCWs who worked in the high-risk and non-high-risk areas (odds ratio [OR], 14.415; 95% confidence interval (CI): 4.733 – 43.896). Comparisons of the CT signs between the active and inactive groups via chi-square tests revealed that the tree-in-bud, cavity, fibrous shadow, and calcification signs exhibited significant differences (P = 0.000, 0.021, 0.001, and 0.024, respectively). Tree-in-bud and cavity opacities suggest active pulmonary tuberculosis, whereas fibrous shadow and calcification opacities are the main features of inactive pulmonary tuberculosis. Comparison with the final comprehensive diagnoses revealed that the sensitivity and positive predictive value of the diagnoses of active PTB based on LDCT alone were 100% and 86.4%, respectively.

Conclusions

Healthcare workers in tuberculosis hospitals are a high-risk group for active PTB. Yearly LDCT examinations of such high-risk groups are feasible and necessary.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-017-0274-6) contains supplementary material, which is available to authorized users.

The Direct Comparison of Two Interferon-gamma Release Assays in the Tuberculosis Screening of Japanese Healthcare Workers

Objective Two interferon-gamma release assays (IGRAs), the QuantiFERON-TB Gold In-Tube (QFT-GIT) and T-SPOT.TB (T-SPOT), are commercially available. The agreement between the two IGRAs in the screening of healthcare workers (HCWs) for latent tuberculosis is not well known. Methods The QFT-GIT and T-SPOT tests were performed for the baseline tuberculosis screening of 654 HCWs who worked at Mie University Hospital in Japan. The results of the two tests were directly compared. Results Nineteen (2.9%), 28 (4.3%) and 33 (5.0%) of the 654 HCWs were found to be positive by the QFT-GIT, T-SPOT, and the QFT-GIT and/or T-SPOT methods using cut-off values of 0.35 IU/mL (QFT-GIT) and 6 spots (T-SPOT). After excluding 4 cases with indeterminate results, there were 14 concordant positive (2.2%), 618 concordant negative (95.1%), and 18 discordant (2.8%) results using the cut-off values of 0.35 IU/mL (QFT-GIT) and 6 spots (T-SPOT). The agreement of the two IGRAs was 97.2% (κ=0.595). When cut-off values of 0.35 IU/mL (QFT-GIT) and 8 spots (T-SPOT) were applied, there were 11 concordant positive (1.7%), 626 concordant negative (96.3%), and 13 discordant (2.0%) results, with 98.0% agreement (κ=0.618). When the borderline criteria for the QFT-GIT (0.1 to <0.35 IU/mL) and T-SPOT (5-7 spots) were applied, there were 11 concordant positive (1.7%), 11 concordant borderline (1.7%), 586 concordant negative (90.2%), and 42 discordant (6.5%) results, with 93.5% agreement between the two methods (κ=0.538). Conclusion When standard cut-off values were used, the agreement between the two IGRAs in the tuberculosis screening of Japanese HCWs was moderate to high. Importantly, some HCWs showed discordant results, especially those whose results were in the borderline zones.

Preventing the Transmission of Tuberculosis in Health Care Settings: Administrative Control

It is well established that health care workers (HCWs) have a considerably higher risk of occupationally acquired tuberculosis (TB). To reduce the transmission of TB to HCWs and patients, TB infection control programs should be implemented in health care settings. The first and most important level of all protection and control programs is administrative control. Its goals are to prevent HCWs, other staff, and patients from being exposed to TB, and to reduce the transmission of infection by ensuring rapid diagnosis and treatment of affected individuals. Administrative control measures recommended by the United States Centers for Disease Control and Prevention and the World Health Organization include prompt identification of people with TB symptoms, isolation of infectious patients, control of the spread of the pathogen, and minimization of time spent in health care facilities. Another key component of measures undertaken is the baseline and serial screening for latent TB infection in HCWs who are at risk of exposure to TB. Although the interferon-gamma release assay has some advantages over the tuberculin skin test, the former has serious limitations, mostly due to its high conversion rate.

Updates on the risk factors for latent tuberculosis reactivation and their managements

The preventive treatment of latent tuberculosis infection (LTBI) is of great importance for the elimination and control of tuberculosis (TB) worldwide, but existing screening methods for LTBI are still limited in predicting the onset of TB. Previous studies have found that some high-risk factors (including human immunodeficiency virus (HIV), organ transplantation, silicosis, tumor necrosis factor-alpha blockers, close contacts and kidney dialysis) contribute to a significantly increased TB reactivation rate. This article reviews each risk factor's association with TB and approaches to address those factors. Five regimens are currently recommended by the World Health Organization, and no regimen has shown superiority over others. In recent years, studies have gradually narrowed down to the preventive treatment of LTBI for high-risk target groups, such as silicosis patients, organ-transplantation recipients and HIV-infected patients. This review discusses regimens for each target group and compares the efficacy of different regimens. For HIV patients and transplant recipients, isoniazid monotherapy is effective in treating LTBI, but for others, little evidence is available at present.

The increased risk of active tuberculosis disease in patients with dermatomyositis - a nationwide retrospective cohort study

The risk of active tuberculosis (TB) in patients with dermatomyositis (DM) is poorly understood. The cohort study aimed to investigate the association between DM and the risk of active TB disease. We conducted a population based study on 4,958 patients with newly diagnosed DM and 19,832 matched controls according to age, sex, and index date between 1998 and 2008. The hazard ratios (HRs) and cumulative incidences of active TB disease between DM patients and controls were analyzed. During the study period, a total of 85 (1.7%) DM patients developed active TB disease, which was significantly higher than that of non-DM patients (0.64%). The incidence rate of active TB disease was higher among DM patients than controls (incidence rate ratio 2.95; 95% confidence interval [CI], 2.24 to 3.88). The Cox regression model demonstrated significantly higher active TB disease rate among DM patients compared with controls (adjusted HR, 2.64; 95% CI, 1.97 to 3.54; p < 0.001) after adjusting for age, sex, and underlying medical disorders. The most significant risk factors for developing active TB included male sex, diabetes mellitus comorbidity, and use of corticosteroids and azathioprine in DM patients. In conclusion, DM patients are at a greater risk for active TB disease.