Spread of a drug-resistant strain of mycobacterium tuberculosis among homeless people in a German city

Cases of active pulmonary tuberculosis are much more common among homeless people because of their personal risk factors than in the average population; it is assumed that there are about 500 000 homeless people in the Federal Republic of Germany. Several sputum samples were sent from the tuberculosis advice center of the public health office in Hannover to the governmental institute of public health services of Lower Saxony in fall 1996 in order to carry out laboratory tests for mycobacteria. The isolates found revealed an unusual pattern of drug resistance to streptomycin and rifampin. The sputum samples were tested according to the usual standard test procedures as described in DIN 58 943-3 (DIN standard of the German Institute for Standardization) and in MiQ 5/1998 (Quality standards in microbiology-infectiologic diagnostics issued by the German Society for Hygiene and Microbiology [DGHM]. DNA-fingerprinting was carried out by the IS 6110-RFLP-technique. In Hannover a total of 12 patients with an active pulmonary tuberculosis, whose M. tuberculosis-strains showed resistance to streptomycin and rifampin, were investigated. 9 of the 12 patients were homeless and lodged in a homeless shelter of the city; in one case a healthcare worker acquired a tuberculosis infection while caring for these patients. The identity of the 12 isolated mycobacteria strains could be proved by IS 6110-fingerprinting. The result clearly indicates the existence of a tuberculosis cluster among the homeless people in a German city. The treatment of the homeless persons proved to be difficult because of the lack of compliance; in 4 cases compulsory isolation with therapy in a closed clinic was unavoidable and beforehand 2 of the patients even had to be tracked down by the police. The German law on the prevention of infectious diseases offers some new possibilities to the public health offices concerning the control and prevention of tuberculosis among homeless persons. For example the public health offices are now allowed to run a "preventive visiting services" prevention and to practice ambulant therapies; the payment of the costs for poor patients is prescribed, too. These possibilities should be used in an extended way, as the efforts to control the spread to tuberculosis among homeless people need to be intensified.