What factors contributed to the delayed diagnosis and high case fatality rate in the MDRTB outbreaks in hospitals between 1988 and 1992?

The delayed diagnosis was caused by the fact that most patients were also infected with HIV, so TB did not present in a classic manner. Recognition of drug resistance was also delayed because drug susceptibility testing took too long, and this contributed to the high case fatality rate.

During the MDRTB outbreaks between 1988 and 1992, most of the affected patients were also infected with HIV. Because HIV alters the presentation of tuberculosis, TB did not always appear in the usual, recognizable way, which delayed diagnosis. In addition, the time needed to complete drug susceptibility tests was long, so the presence of drug resistance was not recognized promptly. These delays in diagnosis and in identifying drug resistance meant that effective treatment was not started in time, and the case fatality rate was very high: 72% to 89% of patients died within 16 weeks of diagnosis.