Using DNA fingerprinting to detect transmission of Mycobacterium tuberculosis among AIDS patients in two health-care facilities in Puerto Rico.

BACKGROUND: Fourteen cases of tuberculosis (TB) in Puerto Rico, diagnosed from April 1993 to April 1995, had the same DNA fingerprint, documenting disease caused by the same strain of Mycobacterium tuberculosis. The 14 cases were retrospectively investigated for epidemiologic links. METHODS: Records were reviewed and staffs of the TB program, hospital/clinic, and AIDS residential facilities were interviewed. RESULTS: Half of the AIDS cases were epidemiologically related, providing evidence of TB transmission in an emergency department, an AIDS inpatient ward, and an AIDS residential facility. DNA fingerprinting allowed detection of M tuberculosis transmission, but contact investigators could have documented it sooner. Factors contributing to transmission included delayed diagnosis, prolonged infectiousness, inadequate discharge planning and infection control procedures, and poor communication between health-care facilities. CONCLUSIONS: The numbers of AIDS residential facilities are increasing and must understand proper monitoring of TB patients and infection control measures that prevent transmissions.

Clinical and programmatic mismanagement rather than community outbreak as the cause of chronic, drug-resistant tuberculosis in Buenaventura, Colombia, 1998.

SETTING: Buenaventura, Colombia. OBJECTIVE: To assess whether antituberculosis drug resistance was generated by poor management or community transmission. DESIGN: Treatment-failure and new tuberculosis (TB) patients identified between May 1997 and June 1998 were interviewed and their treatment histories reviewed. Bacteriologic testing, including drug susceptibility profiles (DSP) and DNA fingerprinting by restriction fragment length polymorphism (RFLP), was performed and human immunodeficiency virus (HIV) testing was offered. RESULTS: DSP and RFLP fingerprints were obtained for isolates from 34 of 64 treatment-failure patients; 25 (74%) were resistant to > or = one drug. Fifteen of the 25 patients consented to HIV testing; none were positive. An average of 2.8 major treatment errors per patient was identified. RFLP from the treatment-failure patients revealed 20 unique isolates and six clusters (isolates with identical RFLP); 4/6 clusters contained isolates with different DSP. Analysis of the RFLP from both treatment-failure and new patients revealed that 44/111 (40%) isolates formed 18 clusters. Four of 47 (9%) new patients had multidrug-resistant TB (MDR-TB). Eleven isolates belonged to the Beijing family, related to the MDR strain W. CONCLUSION: Drug resistance in Buenaventura results from both poor management and community transmission. Dependence on DSP to identify TB transmission is inadequate when programmatic mismanagement is common.