Epidemiological information from active and passive pyocine typing of Pseudomonas aeruginosa.

An investigation was carried out to determine the value of active and passive pyocine typing in the study of Pseudomonas aeruginosa infections acquired in hospital. Active typing was a more reliable and reproducible method than passive typing. Both methods were used in studies of nine outbreaks of infection. In six of these episodes there was good agreement between the two methods. Less clear-cut results were achieved in the remaining three episodes. In one of these, active typing gave more valuable information. However, both methods are easy, convenient and of value in epidemiological studies.