controls in low- to moderate-risk situations have had mixed results. This may be due to underlying differences in the baseline purified protein derivative (PPD) conversion rates in different hospitals. In addition to the adoption of the whole guidelines, a number of studies have focused on parts of the guidelines. This is particularly true of administrative controls. It is in this area where the most variability in practice will arise, particularly in designing criteria for patient isolation, owing to the wide differences in patient populations seen at different hospitals.
Although compliance with the guidelines in the early 1990s was suboptimal, a number of studies show significant improvements in guideline compliance. However, there are many areas that still have considerable room for improvement, particularly in the education of health care workers about tuberculosis. Information on implementation of the guidelines outside of the inpatient setting of acute-care hospitals is scarce. Some evidence exists that many emergency departments are making progress.
The cost of implementation of the guidelines can be substantial, but many of these costs are one-time facility improvements. Although the ongoing costs of a tuberculosis control program can be substantial, these programs may be relatively cost-effective compared with the costs incurred in evaluating patients or healthcare workers exposed to a nonisolated tuberculosis patient.
After decades of declining rates of tuberculosis in the United States, case rates leveled off and then increased in the late 1980s and early 1990s (1, 2). A number of factors led to the reversal of the previous trend: decreased public health infrastructure, the human immunodeficiency virus (HIV) epidemic, and an influx of immigrants from areas where tuberculosis is endemic (3). The problem was compounded by the fact that many physicians and other healthcare workers had very little experience with tuberculosis. They often did not suspect the diagnosis when a patient with the disease first presented and, even if suspected, often had little appreciation for the infection control issues involved. Almost inevitably, a number of nosocomial outbreaks of tuberculosis occurred, including outbreaks involving multidrug-resistant tuberculosis (MDR tuberculosis) (4, 5, 6, 7, 8, 9, 10). In December 1990, CDC published “Guidelines for Preventing the Transmission of Tuberculosis in Health-Care Settings, with Special Focus on HIV-Related Issues” (11) in response to these outbreaks. Subsequently, these guidelines were expanded and refined with the publication in October 1994 of “Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Facilities, 1994” (12).