BORRELOlVTiCETACEAE 



1295 



of Streptobacillus moniliformis vary con- 

 siderably in the appearance of the 

 colonies, the tendency to reversion to 

 bacillarj' form, and the degree of autoly- 

 sis. The colonies are considerably larger 

 than the colonies of the human or animal 

 pleuropneumonia-like strains; they may 

 reach 1 to 2 mm. Usually a wide periph- 

 eral zone is present and development 

 and autolysis of the large bodies produces 

 a coarse appearance in the colonies. 

 Sometimes no peripheral zone develops, 

 the colony is dome -shaped, and the large 

 bodies have no tendency to autolyze. 

 The young colonies (twelve hours incuba- 

 tion) grow into the agar as loose strands 

 of more or less swollen granules. Serum 

 broth cultures grow in small clumps usu- 

 ally adhering to the wall of the test tube. 



The cultures consist of small granules, 

 small polar-staining bacilli and diph- 

 theroid-like forms which swell to large 

 round forms. In the top layer of fully 

 developed colonies, the well-stained large 

 bodies may be as large as 10 to 20 microns. 

 By vacuolization they transform into 

 empty blebs. By segmentation of their 

 contents, the large forms may reproduce 

 the small bacillary forms. In suitable 

 preparations chromatin bodies are visible 

 both in the small and large forms. The 

 small forms are filterable through Berk- 

 feld candles; the size of the smallest 

 particles has not been exactly deter- 

 mined. The organism is very soft and 

 fragile . 



Their growth requirements and bio- 

 chemical activities are similar to those of 

 Streplohacill us moyiiliform is . 



Growth occurs on nutrient agar con- 

 taining animal .serum or egg yolk. Some- 

 times there is a slight growth on boiled 

 blood agar plates without serum. Good 

 growth is obtained in a mineral solution 

 with 0.1 per cent starch. Growth is 

 both aerobic and anaerobic. 



The Li form is more resistant to heat 

 and to aging of the culture than is the 

 streptobacillus and it has a remarkable 

 resistance to penicillin to which the bac- 



teria are very sensitive. Like the bacil- 

 lus, Li produces acid but no gas from 

 glucose, maltose, fructose, salicin, starch, 

 and dextrin. It gives no oxidase test. 



Serologically the Li form is similar to 

 Streptobacillus moniliformis and different 

 from the members of the pleuropneu- 

 monia group. It has no pathological 

 effect on mice, rats or guinea pigs. It 

 does not produce an infection of the 

 chicken embryo. It can be isolated from 

 freshly isolated strains of Streptobacillus 

 moniliformis, from several-day old broth 

 and agar cultures, from broth cultures 

 heated at 56°C. and usually also from 48 

 hour agar cultures if they are incubated 

 at 28° to 30°C. It is questionable 

 whether the Li form has been isolated 

 directly from rats. 



Klieneberger (Jour. Uyg., 40, 1940, 204) 

 isolated a similar strain from a bacterium 

 similar to Streptobacillus moniliformis 

 which caused abscesses in guinea pigs. 

 Whether this bacterium was identical or 

 different from Streptobacillus monili- 

 formis was not determined. 



2, Pleuropneumonia-like organisms 

 isolated from Bacteroides funduliformis. 

 Dienes (Proc. Soc. Exp. Biol, and Med., 

 47, 1941, 385) and Dienes and Smith 

 (Jour. Bact., 48, 1944, 125) isolated cul- 

 tures from two strains of Bacteroides 

 funduliformis which could be propagated 

 indefinitely and which in morphology and 

 in the appearance of colonies were closely 

 similar to Li. 



The young colonies consisted of similar 

 strands of granules growing into the 

 medium. The surface of fully developed 

 colonies consisted of large bodies and a 

 honey-comb-like structure. The well 

 isolated colonies grew usually to a fairly 

 large size (1 to 2 mm). 



Both strains, transplanted every two 

 or three days through several months, 

 failed to reproduce bacteria either on agar 

 or submerged in broth. 



No growth was obtained in liquid cul- 

 tures. 



