Chapter 24: Culture Media for the Detection and Enumeration of Legionella Species in Water

Legionella species are common in aquatic habitats. At least 49 species of the genus Legionella have been described, of which approximately 40% have been implicated in human disease. The transmission route is via aerosols containing Legionella and can cause “legionnaires’ disease” or a milder form, “Pontiac fever”. Owing to the complexity of the heterogeneous group of Legionella species and the diversity of water samples, there is no gold standard for the isolation of Legionella species from water. Cultivation of Legionella requires special media supplemented with the amino acid L-cysteine. This amino acid, together with BCYEα (buffered charcoal yeast extract agar with α-ketoglutarate), forms the base for Legionella culture media. Depending on the source of the water to be analysed, it is necessary to use different combinations of antibiotics. Therefore different types of media have been developed since the first Legionella was cultured in 1977. The history of the development of various culture media for the isolation of Legionella species is described in this chapter.