Molecular typing of Legionella pneumophila serogroup 1 isolates from patients and the nosocomial environment by arbitrarily primed PCR and pulsed-field gel electrophoresis

J Med Microbiol. 1999 Apr;48(4):327-333. doi: 10.1099/00222615-48-4-327.


The ubiquity of Legionella pneumophila in aquatic habitats means that epidemiological evaluation is important for the investigation and control of nosocomial outbreaks of legionellosis. Pulsed-field gel electrophoresis (PFGE) of chromosomal DNA following digestion with SfiI is considered to be one of the most discriminative methods for detecting DNA polymorphisms amongst L. pneumophila serogroup 1 (Lp1) isolates. This paper describes an arbitrarily primed PCR (AP-PCR) method with three different primers (20-mers) for detecting DNA polymorphisms of Lp1 isolates. The AP-PCR assay was compared with PFGE analysis. Both experimental methods were found to have good discriminatory power (discrimination index of 98% and 94.3%, respectively) with 27 unrelated isolates from different geographical areas collected between 1987 and 1997. Furthermore, when the AP-PCR was used in the epidemiological investigation of nosocomial cases of infection, convergent results with the three primers allowed an epidemiological link to be established between isolates from patients and their environment. The AP-PCR method, which is rapid and easy to perform, gave results at least as discriminatory as those obtained with the PFGE method and is proposed for use in the molecular typing of Lp1 outbreaks.

Publication types

  • Comparative Study

MeSH terms

  • Bronchi / microbiology
  • Bronchoalveolar Lavage Fluid / microbiology
  • Cross Infection / epidemiology
  • Cross Infection / microbiology*
  • Cross Infection / prevention & control
  • DNA Primers / chemistry
  • DNA, Bacterial / analysis*
  • Disease Outbreaks / prevention & control*
  • Electrophoresis, Gel, Pulsed-Field
  • Environmental Microbiology
  • Humans
  • Legionella pneumophila / classification*
  • Legionella pneumophila / genetics
  • Legionnaires' Disease / epidemiology
  • Legionnaires' Disease / microbiology*
  • Legionnaires' Disease / prevention & control
  • Polymerase Chain Reaction
  • Polymorphism, Genetic
  • Serotyping


  • DNA Primers
  • DNA, Bacterial