STUDIES ON VEILLONELLOPHAGES ISOLATED FROM WASHINGS OF HUMAN ORAL CAVITY

抄録

Virulent phages specific for Veillonella were isolated from washings of the oral cavity of 200 individuals. These phage strains were classified into two major groups, A (N1-11) and B (19-36), by their plaque morphology and serological characters. By the susceptibility to these phages, 21 strains of genus Veillonella were classified into four types (type I to IV). Type I corresponded to V. parvula, type II to V. reniformis, type III to V. alcalescens, and type IV to other strains of Veillonella. The growth curve of veillonellophage N2, N11, and N20 propagated on each of their host Veillonella revealed that they had a latent period of 55 min to maximum of 100 min, burst size ranging 40-120 and eclipse period of 20 to 100 min. Electron microscopy revealed that the group A phage had a hexagonal head of 670 Å diameter and wedge-shaped tail of 180 Å phage length and 90-180 Å width at the base. They were classified as type C according to Bradlaγs definition. Group B phages with a hexagonal head of 550 Å diameter, and a striated tail of 1300 Å length and 70 Å width were classified as type B of Bradley’s definition. More than 90% of group A phages and their host Veillonella were inactivation by ultraviolet (UV) irradiation, but group B phages and their host were comparatively resistant to UV irradiation. Photoreactivation of veillonellophages were not observed under aerobic and anaerobic condition.