Effectiveness of infection control measures in controlling a nosocomial outbreak of multidrug-resistant tuberculosis among HIV patients in Italy

Int J Tuberc Lung Dis. 2000 Jan;4(1):61-8.


Setting: Between October 1992 and February 1994, 33 cases of multidrug-resistant tuberculosis (MDR-TB) were diagnosed among patients infected by the human immunodeficiency virus (HIV) and hospitalised in an HIV ward in Milan, Italy. This outbreak was part of a much larger outbreak, begun in another hospital and probably transferred through a patient.

Objective: To evaluate risk factors for transmission and the effectiveness of infection control measures.

Design: 1) Active follow-up of exposed patients, 2) cohort study among HIV-infected patients exposed to MDR-TB cases before and after the implementation of control measures, 3) screening of close contacts of MDR-TB cases, and 4) molecular typing by restriction fragment length polymorphism (RFLP) analysis.

Results: The risk of MDR-TB was higher in patients with lower CD4+ lymphocyte percentages and longer duration of exposure. No difference in the daily risk was observed for in-patients vs day-hospital patients or by room distance from an infectious case. Of the 90 patients exposed before the implementation of infection control measures (i.e., October 1992-June 1993) 26 (28.9%) developed MDR-TB, whereas none of the 44 patients exclusively exposed after implementation developed MDR-TB, despite the continuing presence of infectious MDR-TB cases in the ward.

Conclusion: Simple control measures were effective in significantly reducing nosocomial transmission among patients.

MeSH terms

  • AIDS-Related Opportunistic Infections / epidemiology*
  • AIDS-Related Opportunistic Infections / microbiology
  • AIDS-Related Opportunistic Infections / prevention & control
  • Cross Infection / epidemiology*
  • Cross Infection / prevention & control
  • Disease Outbreaks* / prevention & control
  • HIV Infections / epidemiology*
  • Humans
  • Infection Control*
  • Italy / epidemiology
  • Risk Factors
  • Tuberculosis, Multidrug-Resistant / epidemiology*
  • Tuberculosis, Multidrug-Resistant / prevention & control