[Legionella pneumophila serogroup 3 isolated from a patient of pneumonia developed after drowning in bathtub of a hot spring spa].

A 71-year-old Japanese female, was found unconscious by drawing, in a hot spring spa, at around noon of 20 October 1994. She recovered by emergency cardiopulmonary resuscitation, and admitted to the Takinomiya General Hospital, with adult respiratory distress syndrome (ARDS). Although she recovered from ARDS within 4 days after her admission, she developed severe pneumonia accompanied with the second attack of ARDS. Ordinary bacteriological culture of her respiratory specimens failed to yield any significant pathogen for her pneumonia, and neither cefazolin nor imipenem/cilastatin was effective. Thus minocyclin was given on the 7th hospital-day and this was effective for blood gas and C-reactive protein (CRP) levels. Intratracheal exsudate inoculated on BCYE alpha agar plate yielded grayish white colonies. Cells of the colonies were clearly agglutinated by anti-Legionella pneumophila serogroup (SG) 3 serum. Antibody titers of patient's paired sera against the strain L. pneumophila SG3 Bloomington-2 and the patient's strain (Y-1) were determined by microplate agglutination test, and a significant rise from 1:20 to 1:320 was demonstrated. Patient recovered by erythromycin treatment and was discharged on the 59th hospital day. L. pneumophila SG3 organisms were again isolated from the spa water where the patient drawn. From these findings described above, we diagnosed the patient as pneumonia due to L. pneumophila SG3, and the spa water was the most probable source of infection.