Multi-drug-resistant tuberculosis in a Department of Infectious Diseases

Abstract

In Western Europe, Portugal has the highest incidence of tuberculosis (TB) as well as HIV infection. At the Department of Infectious Diseases, Hospital de Santa Maria, Lisbon, we have observed a steady increase in cases of drug resistant (DR) and multi-drug resistant (MDR) TB over the last few years. To identify the determinants of drug- resistant tuberculosis, clinical notes from all patients admitted to the Department of Infectious Diseases from 1995 to 2000, with DR- or MDR-TB were retrospectively reviewed. A total of 212 samples, from 190 patients with tuberculosis were tested for sensitivity to first line anti-TB drugs, using standard methods. Most patients (61%) were intravenous drugs users. Resistance to at least one drug was found in 44 patients (23%); notes were available for review in 39 (36 HIV infected) patients. The rate of DR-TB was 9% (n=16) and that of MDR-TB was 15% (n=28). Almost half of the MDR-TB cases (n=13) showed resistance to four drugs (HRSE). Thirteen patients (69%) were first diagnosed as fully sensitive tuberculosis, during their first admission to the Department; however, later on they developed MDR-TB or DR-TB. Non-compliance with therapy and the intravenous use of drugs were associated with MDR-TB. The large increase in MDR-TB in our Department is of great concern. The clustering of identical resistance patterns suggest transmission of TB from a single source patient that may well have occurred in a nosocomial context. Traditional tuberculosis control measures seem to be insufficient in settings were prevalence of HIV infection and tuberculosis are high. This becomes even more important when the incidence of intravenous substance abuse, and often non-compliance, are predominant factors. Appropriate isolation facilities for all suspected tuberculosis cases as well as rapid diagnostic and drug susceptibility tests will be required to prevent further spread of MDR-TB.