Legionellosis in Japan: A Self-inflicted Wound?

Abstract

Legionellosis is a serious bacterial infection characterized by atypical pneumonia primarily due to infection with L. pneumophila, and bathing can be a potential cause of this infection. Legionellosis was first identified in 1977, and it is caused by Gram-negative bacteria belonging to the genus Legionella. Legionellosis remains an important public health threat, particularly in Japan, where the population is rapidly aging, thereby becoming more at risk for developing severe disease and accompanying life-threatening pneumonia. The bacteria are most commonly transmitted via the inhalation of contaminated aerosols produced and broadcast via water sprays, jets or mists. Infection can also occur via the aspiration of contaminated water or ice, or through inhalation of contaminated dust. Because the signs and symptoms of LD, as well as radiographic imaging are similar to pneumonia caused by other pathogens, a specific diagnostic test is required, such as a urine antigen detection test. Six clinical and laboratory parameters, a high body temperature, a non-productive cough, low serum sodium and platelet counts, and high lactate dehydrogenase (LDH) and c-reactive protein concentrations can be used to reliably predict the likelihood of LD. The first choices for chemotherapy are fluoroquinolone and macrolide antibiotic drugs. The main goals of LD prevention measures are 1) the prevention of microbial growth and biofilm formation, 2) the removal of all biofilm formed on equipment and in facilities, 3) minimizing aerosol splash and spread, and 4) minimizing bacterial contamination from external sources. It is apparent that, in Japan, where hot spring (onsen) bathing is common among aged people, strict regulations need to be in place-and enforced-to ensure that all Japanese onsens and spas provide a safe environment and undertake regular, effective infection control practices.

Legionella pneumophila—Virulence Factors and the Possibility of Infection in Dental Practice

“…Legionnaires' disease is a pulmonary form of legionellosis with an incubation period of two to fourteen days, and involves severe pneumonia and systemic infection [32,33]. A benign flu-like condition is called Pontiac fever [34]. It is a non-pneumonic disease with unclear pathogenesis requiring no antimicrobial treatment [32].…”

“…It is a non-pneumonic disease with unclear pathogenesis requiring no antimicrobial treatment [32]. The mortality rate of adequately treated patients with Legionnaires' disease varies from 7% to 24%, with immunocompromised and elderly patients being the most susceptible [34]. It is estimated that 25,000 to 100,000 people are diagnosed with legionellosis each year in the United States [35].…”