Serial testing of healthcare workers for latent tuberculosis infection and long-term follow up for development of active tuberculosis.

Youngmok Park,Young Sam Kim,Young Ae Kang,Jeong Wha Kim,Moo Suk Park,Joon Chang,Song Yee Kim,Katalin Andrea Wilkinson

doi:10.1371/journal.pone.0204035

Youngmok Park, Young Sam Kim + Show 6 more

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https://doi.org/10.1371/journal.pone.0204035

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Abstract

BackgroundHealthcare workers (HCWs) are at high risk of tuberculosis (TB) infection due to occupational exposure. It is important to diagnose TB infections in HCWs to prevent nosocomial transmission, particularly among immunocompromised patients.ObjectiveThe aim of this study was to analyze the rate of tuberculin skin test (TST) conversion and to assess the incidence of active TB after the latent TB infection screenings in high-risk HCWs.MethodsThis retrospective cohort study involved 458 HCWs in TB-related departments between 2009 and 2013. All HCWs underwent a TST and a chest radiograph annually; an interferon-γ release assay (IGRA) was performed on the TST-converted subjects. TST-converted and IGRA-positive HCWs underwent treatment for latent TB infection.ResultsThe TST conversion rate was 30.3% from 2009 to 2011 in two years, 7.4% from 2011 to 2012, and 17.4% from 2012 to 2013. Eleven subjects out of 42 TST converters (26%) were IGRA-positive; two of them developed into active pulmonary TB during the follow-up period.ConclusionsThere was significant discordance between TST conversion and IGRA results in high-risk HCWs, and active TB developed only in TST-converted and IGRA-positive HCWs. Therefore, the combined use of TST and IGRA for periodic monitoring of TB infections in high-risk HCWs may be useful.

Highlights

Healthcare workers (HCWs) are at high risk of Mycobacterium tuberculosis infection due to occupational exposure.[1]
Tuberculin skin tests (TST) are used worldwide to diagnose latent TB infection (LTBI), whereas interferon-γ release assay (IGRA), which includes QuantiFERON-TB Gold-in-Tube test (QFT-GIT; Qiagen, Hilden, Germany) and T.SPOT TB test (Oxford Immunotec, Abingdon, UK) are used in some countries according to their national TB programs.[3,4,5]
LTBI screening in healthcare workers infection with either 3 months of isoniazid and rifampicin, 4 months of rifampicin, or 9 months of isoniazid

Summary

Introduction

Healthcare workers (HCWs) are at high risk of Mycobacterium tuberculosis infection due to occupational exposure.[1] The likelihood of tuberculosis (TB) infection in HCWs is influenced by the patients they care for, type of occupation, the regional prevalence of TB, and the efficacy of TB infection control programs.[1,2] If HCWs are diagnosed with infectious TB, the impact of nosocomial TB transmission can be considerable because of immunocompromised patients in healthcare systems. Tuberculin skin tests (TST) are used worldwide to diagnose LTBI, whereas interferon-γ release assay (IGRA), which includes QuantiFERON-TB Gold-in-Tube test (QFT-GIT; Qiagen, Hilden, Germany) and T.SPOT TB test (Oxford Immunotec, Abingdon, UK) are used in some countries according to their national TB programs.[3,4,5] no effective method for periodic screening of LTBI in high-risk HCWs in moderate to high TB burden areas has been developed. It is important to diagnose TB infections in HCWs to prevent nosocomial transmission, among immunocompromised patients

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