title: An outbreak of multidrug-resistant tuberculosis involving HIV-infected patients of two hospitals in Milan, Italy. Italian Multidrug-Resistant Tuberculosis Outbreak Study Group.
abstract: OBJECTIVE
  To describe an outbreak of multidrug-resistant tuberculosis (MDR-TB), amongst HIV-infected patients, spread from one hospital in Milan to another.
  
  
  METHODS
  Descriptive epidemiological investigation and molecular typing.
  
  
  METHODS
  All cases identified by intensive case-finding were described in terms of clinical characteristics, previous nosocomial exposure to an infectious MDR-TB patient, previous stays in other institutional settings where exposure to MDR-TB could have occurred, and restriction fragment length polymorphism (RFLP) pattern.
  
  
  RESULTS
  Between October 1991 and July 1995, 116 cases of MDR-TB were identified (85 at hospital A and 31 at hospital B). A single case patient, infected at hospital A, introduced the strain into hospital B. Eighty-two of the 92 strains available for fingerprinting revealed an identical pattern; 10 strains had unique RFLP patterns. Nosocomial exposure to an infectious MDR-TB patient was ascertained for 39 of the 56 patients with the 'outbreak' RFLP strain at hospital A (69.6%) and for 24 of the 26 patients at hospital B (92.3%). The median duration of exposure was 32 days at hospital A and 40 days at hospital B. For eight patients with the outbreak strain, exposure was determined to have probably occurred in other hospitals, in the community or in prison.
  
  
  CONCLUSIONS
  This is the largest nosocomial outbreak of MDR-TB reported in Europe. Exposure to MDR-TB cases in other institutions caring for HIV-infected patients probably contributed to the spread of this epidemic. Strict control measures should be immediately adopted in order to prevent the spread of TB amongst HIV-infected patients in institutional settings in Europe.
authors.affiliation: Laboratorio di Epidemiologia e Biostatistica, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: M L
authors.initials: ML
authors.lastname: Moro
authors.forename: A
authors.initials: A
authors.lastname: Gori
authors.forename: I
authors.initials: I
authors.lastname: Errante
authors.forename: A
authors.initials: A
authors.lastname: Infuso
authors.forename: F
authors.initials: F
authors.lastname: Franzetti
authors.forename: L
authors.initials: L
authors.lastname: Sodano
authors.forename: E
authors.initials: E
authors.lastname: Iemoli
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D000328:Adult; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D005260:Female; D006786:Hospitals, Urban; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics; D012150:Polymorphism, Restriction Fragment Length; D018088:Tuberculosis, Multidrug-Resistant / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission