Legionella pneumophila mip gene sequencing to investigate a cluster of pneumonia cases.

Aims: To use fluorescent antibody (FA) and PCR studies on fixed lung tissue to investigate whether Legionella pneumophila was the cause of pneumonia in a cluster of three haematology patients.

Methods: Cut sections of paraffin blocks of lung tissue were examined by direct FA (DFA) using fluorescently labelled antibody to serogroup 1 and Pontiac strains of L. pneumophila.

A mutation in an ompR-like gene on a Legionella longbeachae serogroup 1 plasmid attenuates virulence.

Examination of a panel of Legionella longbeachae serogroup 1 strains using a guinea pig model of virulence determined that this clonal species of Legionella shows a remarkable variation in symptoms and disease outcome (Doyle et al., Infect. Immun.