Molecular Determination of Infection Source of a Sporadic Legionella Pneumonia Case Associated with a Hot Spring Bath

Abstract

To determine the infection source of a sporadic Legionella pneumonia case associated with a hot spring bath, we used five molecular methods, including repetitive element polymerase chain reaction (rep-PCR), arbitrarily primed PCR (AP-PCR), ribotyping, restriction endonuclease analysis (REA), and macrorestriction endonuclease analysis (MREA) by pulsed-field gel electrophoresis. L. pneumophila serogroup (SG) 3 strain EY 3702, isolated from an intratracheal specimen of a 71-year-old Japanese female who developed pneumonia after nearly drowning in a hot spring spa bath, produced rep-PCR and AP-PCR fingerprints identical to those of L. pneumophila SG 3 strains EY 3768 and EY 3769 isolated from the bath water. Four epidemiologically unrelated L. pneumophila SG 3 strains 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 PstI, by REA with EcoRI or Hindill, and by MREA with Nod. Based on these results, we identified the bath water of the hot spring spa as the source of infection of this patient, even though the viable number of the organisms in the bath water was low (3 CFU/100 ml) when determined 27 days after her nearly drowning.

Legionella Pneumonia due to Exposure to 24-hour Bath Water Contaminated by Legionella pneumophila Serogroup-5

“…However, strains of Legionella pneumophila other than serogroup-1 have also been reported to be the causative agents of Legionella pneumonia, the sources of infection with which seem to be the waters of hot spring spas (6,15). The reason for this difference in causative agents is considered to be differences in bacterial distribution in the environment (3,15,16).…”

“…However, the incidence of Legionella pneumonia in Japan remains far lower than in Western countries (4,5) and there are only a few cases of Legionella pneumonia in which the sources of infection were directly determined to be these waters (6).…”

Hot Spring Bath and Legionella Pneumonia: An Association Confirmed by Genomic Identification.

“…This technique wasshownto be useful for subdividing ribotypes and distinguishing the strains involved in the outbreak of Legionnaires' disease from epidemiologically unrelated strains (24). There is one report that verified, using PFGEand four other molecular techniques, a sporadic Legionella pneumonia case infected from hot spring spa water (6). Of the two outbreaks of Legionnaires' disease recently reported in Japan, one was linked by PFGE to contaminated hot spring bath water (25) and the other was linked to public bath water (26).…”

“…Inspiration of aerosol or aspiration of water contaminated with the bacteria causes community or hospital-acquired pneumonia. Although there have been instances in which the same serotypic Legionella has been recovered from patients with Legionnaires ' disease and environmental water to which the patients had been exposed (4,(6)(7)(8), few investigations have identified the genomes of the strains recovered (6)(7)(8).…”

Bath Water Contamination with Legionella and Nontuberculous Mycobacteria in 24-Hour Home Baths, Hot Springs, and Public Bathhouses of Nagano Prefecture, Japan

“…In remarkable contrast to Western countries, the incidence of Legionnaires' disease had remained extremely low in Japan (13,14), with only a few reported cases, for which bath water was determined to be the direct source of infection (15). However, in 2008, 896 cases of legionellosis were reported (16), representing a 5-fold increase in incidence over the previous 5 years (Infecti- Fig.…”