Survey ofLegionellaSpecies Found in Thai Soil

Abstract

Members of the Gram-negative genusLegionellaare typically found in freshwater environments, with the exception ofL. longbeachae, which is present in composts and potting mixes. When contaminated aerosols are inhaled, legionellosis may result, typically as either the more serious pneumonia Legionnaires’ disease or the less severe flu-like illness Pontiac fever. It is presumed that all species of the genusLegionellaare capable of causing disease in humans. As a followup to a prior clinical study of legionellosis in rural Thailand, indigenous soil samples were collected proximal to cases’ homes and workplaces and tested for the presence of legionellae by culture. We obtained 115 isolates from 22/39 soil samples and used sequence-based methods to identify 12 known species ofLegionellarepresented by 87 isolates.