In order to investigate the pathogenicity of the non-spore forming anaerobe, we inoculated mice (15g) intraperitoneally with various dilutions of normal saline suspensions of non-spore forming anaerobes isolated chiefly from gallbladder, and LD
50 was calculated in colony count respectively.
Each mouse was autopsied and investigated pathologically. The same procedures were done with aerobes.
1) LD
50s of various species of anaerobic rods were as follows: 10
9.9 of Eubacterium (3 strains), 10
11.0 of Corynebacterium (4 strains out of 6) and 10
12.4 of Ramibacterium (1 strain). With regard to cocci, LD
50s were obtained in only 3 strains out of 8; 10
8.6 of Peptostreptococcus intermedius (1 strain), 10
11.5 of Peptococcus (1 strain), 10
11.6 of Veillonella (1 strain). On the other hand, LD
50s of aerobes were as follows; 10
10.0 of E. Colli (3 strains), 10
10.8 of Staphylococcus aureus (3 strains), and 10
7.4 of β-streptococcus (3 strains).
2) Although vilurence of the anaerobes is inferior to that of the aerobes in general, there are many strains that are equal or superior to pathogenic aerobes in vilurence, such as whole strains of Eubacterium, many strains of Corynebacterium and some strains of Peptostreptococcus.
3) The pathological examination of the experimentally infected mice revealed the followings: In the dead mice group, severe degree of pathological change such as perisplenitis, perisplenal abscess, liver abscess and peritonitis were observed in general. On the other hand, in the survived mice group, pathological changes were slight. It is concluded that many strains of the anaerobes have strong vilurence and pathogenicity.
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