MOLECULAR DETERMINATION OF INFECTION SOURCE OF A SPORADIC LEGIONELLA-PNEUMONIA CASE ASSOCIATED WITH A HOT-SPRING BATH

To determine the infection source of a sporadic Legionella pneumonia c ase associated with a hot spring bath, we used five molecular methods, including repetitive element polymerase chain reaction (rep-PCR), arb itrarily primed PCR (AP PCR), ribotyping, restriction endonuclease ana lysis (REA), and macrorestriction endonuclease analysis (MREA) by puls ed-field gel electrophoresis. L. pneumophila serogroup (SG) 3 strain E Y 3702, isolated from an intratracheal specimen of a 71-year-old Japan ese female who developed pneumonia after nearly drowning in a hot spri ng spa bath, produced rep-PCR and AP-PCR fingerprints identical to tho se of L. pneumophila SG 3 strains EY 3768 and EY 3769 isolated from th e bath water. Four epidemiologically unrelated L. pneumophila SG 3 str ains showed different rep-PCR or AP-PCR fingerprints from those of the three EY strains (EY 3702, 3768, and 3769). The three EY strains were also genotypically indistinguishable by ribotyping with EcoRI and Pst I, by REA with EcoRI or HindIII, and by MREA with NotI. Based on these results, we identified the bath water of the hot spring spa as the so urce of infection of this patient, even though the viable number of th e organisms in the bath water was low (3 CFU/100 ml) when determined 2 7 days after her nearly drowning.