Performance Improvement Project to Identify Factors that Led to Employee Exposure to Mycobacterium tuberculosis

Background:   The New York Hospital Queens Tuberculosis Control Policy aims to provide appropriate treatment for patients, offer prophylaxis to infected staff members, and prevent nosocomial transmission to patients and staff.  It describes procedures to identify patients with active tuberculosis by clinical and laboratory means, report cases of tuberculosis to the New York City Department of Health, and isolate patients with confirmed or suspected infectious tuberculosis.  It emphasizes the involvement of the Infection Control Unit when instituting and withdrawing respiratory isolation.  Despite having such a policy, situations occur which result in unwarranted, direct, prolonged contact to patients with active, symptomatic tuberculosis exposure. 

Objective: The goal of this study was to identify factors that led to patient and hospital staff exposure to Mycobacterium tuberculosis at New York Hospital Queens.

Methods:   A retrospective study between January 2003 and December 2007 was conducted.  The Institutional Review Board approved the study.  Data from the Infection Control Unit were reviewed to determine the number of patients or staff, who were subject to unprotected exposure to Mycobacterium tuberculosis, and the number of patients with positive cultures from whom such exposures occurred.

Results:   There were 165 tuberculosis cases documented during the selected period.  Unprotected exposure of 1067 patients and staff occurred from 23 infected patients.  In seven patients, tuberculosis isolation was initiated appropriately upon admission but was prematurely discontinued.  Isolation was delayed in eight patients.  Eight patients were not isolated during their hospitalization. 

Conclusions:   Our study shows that having three negative acid-fast bacilli smears does not exclude tuberculosis.  In the absence of an alternative diagnosis, isolation should be based on clinical and radiological findings.  Subtle imaging findings should also be considered as a risk factor.  The main factors that led to unnecessary exposure are poor recognition of tuberculosis symptoms and risk factors and the unawareness of the need to involve the hospital Infection Control Unit.  Increased education on initiating and discontinuing tuberculosis isolation is needed.