IDENTIFICATION OF LEGIONELLA-PNEUMOPHILA IN VARIOUS SPECIMENS BY THE POLYMERASE CHAIN-REACTION

Amplification of the mip sequence with polymerase chain reaction (PCR) proved to be specific for Legionella pneumophila. With nested PCR, th e sensitivity of the test was markedly increased The lower limit of de tection for nested PCR in the aqueous medium for live and heat-inacitv ated dead L. pneumophilia was approximately 1-10 bacteria/ml. The sens itivity of the method, however, was reduced by a factor of 10 to 100 w hen the bacteria were added to homogenised pulmonary tissue. Fixing th e bacteria in aqueous suspension or in tissue homogenate with buffered 4 % formalin (pH 7.3) reduced the sensitivity of the PCR by a factor of about 100. After intravenous injection of heat-inactivated bacteria in mice L pneumophila was detected in deep-frozen samples of plasma a nd various tissues. The molecular biological technique of nested PCR i s proposed as an additional method for the diagnosis of legionella.