title: A legionellosis case due to contaminated spa water and confirmed by genomic identification in Taiwan.
abstract: Tracing the source of a legionellosis (LG) case revealed that the Legionella pneumophila (LP) strain isolated from patient's sputum shared the same serogroup (SG) and PFGE-type with 4 LP strains obtained from a spa center. With a high LP-contamination rate (81.2%, 13/16) in all of its 16 basins, this spa center was also found to have a multi-genotypic distribution among its 13 LP isolates, which can be categorized into 5 PFGE-types. Despite such a serious contamination in the spa center, which usually had ca. 100 visitors per day, this male patient, bearing LG-risk factors of long-term heavy smoking and alcoholism, was the only case identifiable after an active investigation. To explore the possible reason for this sporadic infection, all 5 PFGE-types of LP isolated were assayed for their presence of two important virulent genes (lvh and rtx A) and were identified as either less-virulent (lvh (+) , rtx A(+)) or non-virulent (lvh (-), rtx A (-)) types. The strong virulent type (lvh (+), rtx A (+)) usually seen in clinical strains elsewhere was not found here. Moreover, the LG-causative type in this infection was the only one to be classified as the less-virulent type, with the presence of lvh gene indicating its relatively more virulent potential than other 4 PFGE-types. Accordingly, mutual interaction between LP's virulent potential and patient's health-status was suggested to be the force directing the opportunistic infection of this sporadic case. This is the first spa-associated infection caused by SG 2 of LP.
authors.affiliation: Center for Disease Control, Department of Health Taiwan, Taipei, Taiwan.
authors.forename: Hsun-Pi
authors.initials: HP
authors.lastname: Su
authors.forename: Lei-Ron
authors.initials: LR
authors.lastname: Tseng
authors.forename: Shin-Chan
authors.initials: SC
authors.lastname: Tzeng
authors.forename: Chen-Ying
authors.initials: CY
authors.lastname: Chou
authors.forename: Tung-Ching
authors.initials: TC
authors.lastname: Chung
mesh_terms: D000328:Adult; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D005838:Genotype; D006801:Humans; D016952:Legionella pneumophila / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D007876:Legionellosis / Q000382:microbiology*; D008297:Male; D013624:Taiwan; D014871:Water Microbiology
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; C459580:Lvh protein, Legionella pneumophila; C434464:RtxA protein, Vibrio cholerae