Delay in diagnosis leading to nosocomial transmission of tuberculosis at a New York City health care facility

Background: Demographic changes have increased the number of elderly individuals for whom age-related immunosenescence may increase latent tuberculosis (TB) infection (LTBI) activation risk. As TB rates decline, maintaining clinical suspicion for TB is challenging. Timely identification, isolation, and treatment of infectious patients are especially important in settings with vulnerable individuals. Methods: An outbreak investigation was conducted at a long-term care facility/hospital complex after a prolonged TB exposure associated with delayed diagnosis in a tuberculin skin test (TST)-negative cancer patient resulted in a secondary TB case along with other evidence of transmission. Results: Investigators identified 64 patient and 239 staff contacts. Among those tested with TST, 7 (23%) patients and 5 (8%) staff at the long-term care facility had conversions. Because of evidence of transmission, concerns about TST anergy, and the high number of patients with illnesses such as cancer and diabetes that increase TB risk, LTBI treatment was recommended for all exposed long-term care facility patients regardless of TST results once active TB was ruled out. After the investigation concluded, a former patient who tested TST-negative and did not receive LTBI treatment developed active TB. Conclusion: When evaluating symptomatic patients, especially elderly individuals, clinicians should "think TB" regardless of a negative test for TB infection. After known exposure and when transmission evidence exists, clinicians should consider providing LTBI treatment to elderly contacts with comorbidities regardless of LTBI test results. Copyright (C) 2013 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.