[A strain of Pseudomonas vesicularis isolated from shower hose which supports the multiplication of Legionella].

In Japan, a fatal case due to Legionella micdadei was first recognized in our laboratory in 1986. On the epidemiological study just after the case, no Legionella was detected from the environmental samples of the patient's residence, such as shower water, tank water and so on. In the course of prospective investigations, no Legionella was isolated, but many organisms were grown on BCYE alpha and MWY agar plates. In the retrospective study, one of these organisms was found to support satellite growth of Legionella on BCYEagar without L-cysteine. This was the isolate from the shower hose and identified as Pseudomonas vesicularis with the biochemical and DNA-DNA hybridization test. And P. vesicularis type strain ATCC11426 also supported satellite growth of Legionella. Especially in the water supply system, the existence of P. vesicularis seemed to be effective on the growth of Legionella. It must be taken into consideration that efforts made to isolate the nutrient produced organisms as well as Legionella are needed.