The expanded infection control measures led to an eight-fold decrease in Grady health care worker TB skin test conversion rates (i.e., newly positive TB skin test results). The TB skin test conversion rate for Grady health care workers was reduced from 3.3 percent to 0.4 percent following institution of expanded TB infection control measures at Grady, the Annals reported. Over the past six months, the rate has fallen even further, to 0.2 percent, Blumberg said. This rate is well below rates expected at community hospitals, which provide care for far fewer TB patients.
TB is an airborne infectious disease caused by Mycobacterium tuberculosis. Patients with active pulmonary disease can transmit TB to other persons by coughing or sneezing. A positive TB skin test indicates that a person is infected with M. tuberculosis though may not necessarily develop the full-blown or active disease.
Since 1985, there has been a major resurgence of TB in the United States. In 1991 and 1992, the city of Atlanta had the highest rate of active TB in the country according to the U.S. Centers for Disease Control and Prevention (CDC), and the city continues to have very high TB rates. The Grady staff cares for more than 200 patients a year with active TB.
To deal effectively with the TB problem and to prevent its transmission, Grady instituted a series of expanded infection control measures in 1992. Most importantly, said Blumberg, these included administrative controls primarily consisting of an expanded TB respiratory isolation policy. This policy was developed to detect all patients with active pulmonary TB and to meet CDC guidelines on early detection, isolation and treatment of patients with active TB.
Symptoms of TB can consist of cough, fever, night sweats and weight loss. These symptoms can be nonspecific and also associated with other illnesses. All patients with suspected or confirmed TB are admitted to a respiratory isolation room until TB is ruled out or a patient is determined to be noninfectious.
Other administrative controls instituted include the formation of an interdisciplinary TB task force to deal with TB-related issues, the hiring of a full-time nurse epidemiologist to serve as TB control coordinator for the hospital, increased frequency of TB skin testing for staff (from once a year to every six months) and expanded staff education about TB. Other TB infection control efforts included engineering controls (retrofitting additional hospital rooms to serve as isolation rooms) and introduction of a new mask for health care workers who care for TB patients.
"Expanded infection control measures which consisted primarily of administrative controls were very effective in preventing nosocomial (in-hospital) transmission of TB to health care workers," said Blumberg, who is assistant professor of medicine (infectious diseases) at Emory, hospital epidemiologist at Grady and recipient of a $1.1 million grant from the Robert Wood Johnson Foundation to head the Atlanta Tuberculosis Preven-tion Coalition.
"Our experience at an institution located in a high incidence area for TB demonstrates that a high index of suspicion and careful screening of patients for TB is essential and can dramatically reduce health care worker exposure to TB and TB skin test conversion rates," said Blumberg. "Administrative controls appear to be the most important component of a TB infection control program and should be the first focus of such a program, especially at public hospitals, where resources are most likely to be limited."
-- Lorri Preston