Legionellosis (LG, infection by members of the genus Legionella) can range from mild respiratory illness to acute life-threatening pneumonia. The majority of LG cases are caused by Legionella pneumophila (LP), particularly serogroup 1 (18). Since the first outbreak in Philadelphia in 1976 (12), LP has been recognized as an important etiological agent of hospital-and community-acquired pneumonia. This microbe can survive in a wide range of temperature (5-65 C) and pH (5.5-9.5), particularly in warm and damp environments of 35-45 C which is their favorable growth temperature range. Because of their high survival rate in a thermal and wet environment, which happens to be the atmosphere regularly established in a whirlpool spa, numerous outbreaks of LG have been traced to the spa water as the source of their causative agents (2,17,20,21,23,31).Tracing the source of LG was often determined by linking environmental isolates to clinical isolates by various molecular subtyping methods, of which at least 7 kinds have been reported (15). Among them, amplified fragment length polymorphism (AFLP) and pulsefield gel electrophoresis (PFGE) were two methods most often used and highly recommended (3, 13).

We report 2 cases of neonatal Legionella infection associated with aspiration of contaminated water used in hospitals to make infant formula. The molecular profiles of Legionella strains isolated from samples from the infants and from water dispensers were indistinguishable. Our report highlights the need to consider nosocomial legionellosis among neonates who have respiratory symptoms.

The aim of the present study was to investigate the epidemiology of Legionnaires' disease (LD) caused by Legionella longbeachae in Taiwan during 2006-2010. A total of six cases were identified prospectively, accounting for 1.6% of all laboratory-confirmed LD cases and 4.4% of culture-positive LD cases. All six cases occurred between April and August. The male to female ratio was 0.5. These six LD patients had a higher median age than those with LD due to Legionella pneumophila. Four of the six patients presented with pleural effusion and five survived the infection episode. Only two patients had a potential soil contact history prior to LD onset. The patients resided in divergent geographical areas without a common exposure history. The individual genomic DNA banding patterns of the six L. longbeachae isolates analyzed by pulsed-field gel electrophoresis (PFGE) were unique, supporting the hypothesis that the L. longbeachae infections occurred sporadically.

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