Isolation procedure and preliminary characterization of toxin-producing bacteria from Japanese land leech, Haemadipsa zeylanica japonica and medicinal leech, Hirudo medicinalis

Abstract

A group of toxin-producing bacteria was isolated from two species of leeches, the Japanese land leech, Haemadipsa zeylanica japonica and the medicinal leech, Hirudo medicinalis. The culture supernatant of one of the representative strains, designated as Y-1,had a property to cause acute death when it was inoculated in mice not only intravenously but also intraperitoneally. A prominent hyperemia was observed in the mouse skin especially when Y-1 was intravenously inoculated. The lethal and hyperemic effects of Y-1 culture supernatant totally disappeared when it was heated at 100℃ for 10min. The bacterium was found to belong to the Fluorescens group of the genus Pseudomonas. The present investigation revealed that these toxin-producing bacteria are prevalent among leech-inhabiting flora. Consequently it is highly probable that the acute death and the hyperemia due to product (s) of these bacteria might be associated with the blood-sucking behavior of the leech species. Another bacterium was also isolated from the medicinal leech. The bacterium was found to produce a toxic factor (s) which causes mouse death like Haemadipsa bacteria. This bacterium was found to belong to the Fluorescens group of genus Pseudomonas also.