Ridzon R, Kenyon T, Luskin-Hawk R, et al. Nosocomial transmission of human immunodeficiency virus and subsequent transmission of multidrug-resistant tuberculosis in a healthcare worker. Infect Control Hosp Epidemiol 1997; 18: 422-423.
In March 1990, a 32-year-old phlebotomist had a tuberculin skin test conversion following exposure to two patients with tuberculosis. One had TB caused by a fully susceptible Mycobacterium tuberculosis isolate, and the other did not have an isolate recovered.
Following skin test conversion, the HCW was put on preventive therapy with isoniazid, but it was discontinued due to gastrointestinal distress.
In June, the HCW sustained a deep needlestick injury while drawing blood from an AIDS patient. A baseline test for anti-HIV antibodies was negative. Three weeks postexposure the HCW began to experience fever, night sweats, headache, fatigue, and cervical adenopathy. Four weeks post-exposure, HIV p24 antigen was positive. At five weeks, enzyme-linked immunoassay and Western blot were positive for anti-HIV antibodies. CD4 T-lymphocyte count 10 weeks postexposure was 766 cells/mm. The HCW did not receive zidovudine postexposure prophylaxis.
The HCW again was prescribed a six-month course of isoniazid preventive therapy, which again was not completed. In September 1995, the HCW presented with fever, night sweats, cough, and a 30-pound weight loss. A chest radiograph showed hilar fullness and an infiltrate. The CD4 T-lymphocyte count was 65 cells/mm. A sputum specimen showed rare acid-fast bacilli, and culture grew M. tuberculosis resistant to isoniazid and rifampin.
The HCW was treated with isoniazid, rifampin, ethambutol, amikacin, and ofloxacin. When drug susceptibility tests were received, isoniazid and rifampin were stopped. While on therapy, sputum specimens for acid-fast bacilli smear and culture converted to negative and symptoms improved.
The hospital in which the HCW was employed served a community with a low incidence of TB, but from August 1994 through February 1995, a nosocomial outbreak of multidrug-resistant TB occurred among AIDS patients, all of whom were on one floor of the hospital.
At the beginning of the outbreak, negative-pressure rooms were not available. The phlebotomist had drawn blood once on two of the outbreak patients, one of whom had not yet been diagnosed with TB. The other had been diagnosed but not isolated. The phlebotomist reported wearing a high-efficiency particulate air filter respirator when entering the room of the patient with diagnosed TB. The HCW also drew blood on patients on the outbreak floor during nine shifts when an infectious outbreak patient was hospitalized, but not in a negative-pressure isolation room. At the time of exposure, the HCW had a CD4 T-lymphocyte count of 366 cells/mm, was receiving zidovudine therapy, and had no history of opportunistic infections.
Of 74 other HCWs exposed during the outbreak, 11 had documented skin-test conversions and were offered alternative preventive therapy. The phlebotomist was not offered alternative therapy due to the prior positive skin test and perceived limited exposure to infectious patients.
The authors note that the phlebotomist was infected with TB prior to acquisition of HIV. Prior TB infection is believed to protect against reinfection, and people with a prior positive skin test are not usually recommended for preventive therapy during exposure situations. "Recent data suggest that reinfection accounts for a higher-than-expected proportion of TB cases in HIV-infected persons," they state.
In this case, the HCW’s HIV status was known, but it might not be known for other HCWs. "Therefore, all HCWs should be educated about the increased risk for rapid progression to disease from latent M. tuberculosis infection in persons with HIV infection and the possibility of M. tuberculosis reinfection if exposed to patients with infectious TB," the authors advise.
All HCWs should know if they are immune-compromised, and, if they have HIV, should consider work reassignment to limit their exposure to patients with infectious TB. However, this may prove difficult, the authors note, "as even minimal direct exposure may lead to infection."
In cases of exposure to TB that is not resistant to isoniazid or rifampin, HIV-infected HCWs might be offered preventive therapy even in the presence of prior TB infection. Immunosup pressed HCWs should be considered for preventive therapy regardless of skin-test status, the authors say.