Multidrug-resistant Mycobacterium tuberculosis in an HIV dental clinic.

Abstract

To investigate possible transmission of multidrug-resistant tuberculosis (MDR-TB) in a dental setting. A retrospective, descriptive study of dental workers (DWs), patients, and practice characteristics. Two dental workers (DW1 and DW2) with acquired immunodeficiency syndrome and MDR-TB. A hospital-based (Hospital X) human immunodeficiency virus (HIV) dental clinic in New York City. To identify dental patients with tuberculosis (TB), patients treated in the dental clinic at Hospital X during 1990 were cross-matched with those listed in the New York City Department of Health Tuberculosis Registry. Mycobacterium tuberculosis isolates from both DWs and from dental patients with TB were tested for antimicrobial susceptibility and typed by restriction fragment length polymorphism (RFLP) analysis. Infection control practices were reviewed. M tuberculosis isolates infecting DW1 and DW2 were resistant to isoniazid and rifampin and had identical RFLP patterns. DW1 and DW2 worked in close proximity to each other in a small HIV dental clinic in Hospital X during 1990. Of 472 patients treated in the dental clinic in 1990, 41 (8.7%) had culture-proven M tuberculosis infection. Of these 41, 5 had isolates with resistance patterns similar to both DWs; however, for four available isolates, the RFLP patterns were different from the patterns of the DWs. Sixteen of the 41 patients received dental treatment while potentially infectious. Dental patients were not routinely questioned about TB by dental staff, nor were all dental staff screened routinely for TB. No supplemental environmental measures for TB were employed in the dental clinic in 1990. Our investigation suggests that MDR-TB transmission may have occurred between two DWs in an HIV dental clinic. Opportunities for transmission of TB among dental staff and patients were identified. TB surveillance programs for DWs and appropriate infection control strategies, including worker education, are needed to monitor and minimize exposure to TB in dental settings providing care to patients at risk for TB.