Prevalence and correlates of Mycobacterium tuberculosis infection among healthcare workers at the university hospital in Monterrey, Mexico.

BACKGROUND: Healthcare workers (HCWs) are at an increased risk of developing Mycobacterium tuberculosis (Mtb) infection (TBI) due to occupational exposure to patients with active tuberculosis (TB) disease. The risk is heightened in high TB burden regions. This study aimed to determine the prevalence and conversion rates of TBI among HCWs in a TB treatment hospital in Mexico. METHODS: A prospective cohort study of HCWs (n = 178) was conducted at the public University Hospital of the Universidad Autónoma de Nuevo León (UANL) in Monterrey, Mexico from 2017 to 2019. Eligible HCWs working in the emergency or internal medicine departments were tested at baseline using QuantiFERON®-TB Gold Plus (QFT) and Tuberculin Skin Test (TST). Individuals who tested positive were classified as having TBI, while those who tested negative were retested 4-18 months later at a follow-up evaluation. RESULTS: Prevalence of TBI was 63.5% at baseline as detected by QFT and/or TST. Males, nurses, and administrative staff had increased odds of TBI at baseline. Among the 52 participants who tested negative for TBI at baseline, 16 (30.8%) converted to TBI. Combined baseline and follow-up test results indicated fair agreement (kappa = 0.38) between the QFT and TST. CONCLUSION: This study found both high prevalence and conversion of TBI among HCWs at the UANL University Hospital in Monterrey, Mexico and identified associated biological and occupational risk factors. These findings highlight the importance of repeat, short-term testing in regions with high TB prevalence, and underscore the need for improved TBI diagnostics.