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


METHODS
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.


CONCLUSIONS
Simple control measures were effective in significantly reducing nosocomial transmission among patients.
Moro
M L
ML
Laboratorio di Epidemiologia e Biostatistica, Istituto Superiore di Sanità, Rome, Italy.
Errante
I
I
Infuso
A
A
Sodano
L
L
Gori
A
A
Orcese
C A
CA
Salamina
G
G
D'Amico
C
C
Besozzi
G
G
Caggese
L
L
D017088:AIDS-Related Opportunistic Infections / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D003428:Cross Infection / Q000453:epidemiology* / Q000517:prevention & control; D004196:Disease Outbreaks / Q000517:prevention & control; D015658:HIV Infections / Q000453:epidemiology*; D006801:Humans; D017053:Infection Control; D007558:Italy / Q000453:epidemiology; D012307:Risk Factors; D018088:Tuberculosis, Multidrug-Resistant / Q000453:epidemiology* / Q000517:prevention & control