The major species of Legionella of public health significance is Legionella pneumophila serogroup 1 (eg a contaminated cooling tower may cause multiple cases of infection).
In addition to culture of respiratory specimens, diagnosis of L.pneumophila sg1 infection can be performed by detection of Legionella cell-wall antigen in urine. This latter assay has become routine in the management of patients with acute, community-acquired pneumonia.
At our laboratory, testing is performed on a daily basis, with specimens referred from public and private hospitals in Melbourne and country regions in Victoria, southern New South Wales and Tasmania. All positive results are immediately notified to the Department of Human Services Victoria, for case follow-up and identification of any clustering of cases.