FAMILY VI. BACTEROIDACEAE 



453 



Optimum pH, between 7.0 and 8.0. Via- 

 bility rapidly lost with decrease in pH 



Pathogenicity: Usually highly virulent 

 for mice, although certain strains of mice 

 may be rather resistant. Intravenous or 

 intraperitoneal inoculation with 0.1 to 0.5 

 ml of broth culture causes a fatal sepsis, 

 death occurring in 24 to 48 hours, or a 

 chronic disease characterized by purulent 

 polyarthritis, anemia, emaciation, diar- 

 rhea, conjunctivitis and transient or per- 

 manent paralysis involving the hindpart 

 of the body. At necropsy nothing distinctive 

 is found in acute cases; the spleen and lymph 

 nodes are considerably enlarged in subacute 

 and chronic infections, and focal or con- 

 fluent necroses are frequently found in the 

 spleen and liver. Intracutaneous and sub- 

 cutaneous injections cause local abscesses 

 and arthritis and occasionally generalized 

 infection. Bronchopneumonia and sepsis 

 are frequently produced by intranasal in- 

 stillation. Generalized infection has been 

 produced by feeding experiments; the portal 

 of entry in such cases appears to be the sub- 

 ma.xillary and cervical lymph nodes 

 (Freundt, Acta Path, et Microbiol. Scand., 

 38, 1956, 231.) Passage in 9- to 10-day-old 

 chick embryos causes thickening, edema and 

 hemorrhagic lesions of the chorio-allantoic 

 membrane and invasion of the embryo. 

 Rats, rabbits and guinea pigs are generally 

 resistant, although rabbits have been re- 

 ported to be susceptible to certain strains. 



Antigenic structure : Mice and rat strains 

 from three different sources (Levaditi et al., 

 op. cit., 1925, 1188; Mackie, van Rooyen and 

 Gilroy, Brit. Jour. Exp. Path., I4, 1933, 132; 

 Strangeways, Jour. Path, and Bact., 37, 

 1933, 45) were found to be identical by 

 agglutinin absorption tests (van Rooj^en, 

 Jour. Path, and Bact., 43, 1936, 460). 



L-phase variation: In most bacteria in 

 which the L-phase variation is known, ab- 

 normal culture conditions are generally 

 necessary to induce the development of 

 L-type colonies on solid media. All strains 

 oi Streptobacillus moniliformis, on the other 

 hand, develop L colonies spontaneously, 

 though in a variable number. The L-phase 

 variant of S. moniliformis is known as Li 

 (Klieneberger, Jour. Path, and Bact., 40, 

 1935, 93). Klieneberger's original theory. 



that Li was a symbiont of S. moniliformis, 

 was oppo.sed by Dienes (Jour. Inf. Dis., 65, 

 1939, 24; Jour. Bact., 44, 1942, 37), Dawson 

 and Hobby (Proc. 3rd Internat. Congr. for 

 Microbiol., New York, (1939) 1940, Sect. I, 

 177), Heilman (op. cit., 1941, 32), Brown and 

 Nunemaker (op. cit., 1942, 201) and 0rskov 

 {op. cit., 1942, 575), among others; it is now 

 generally accepted, also by Klieneberger- 

 Nobel herself (Jour. Gen. Microbiol., 3, 

 1949, 434), that Li is a variant form of S. 

 moniliformis. 



L-phase colony: The Li colony is defi- 

 nitely smaller than that of the bacillary 

 form, measuring about 0.1 to 0.2 mm in 

 diameter. It contains a round, dark brown 

 center embedded in the agar and consists of 

 tiny, coccoid or coccobacillary elements. 

 The central spot is surrounded by a delicate, 

 translucent, peripheral zone made up of 

 swollen bodies, extracellular fatty droplets 

 and an amorphous substance. Li is ex- 

 tremely resistant to penicillin, while the 

 streptobacilli are very sensitive to this 

 antibiotic. Cross absorption tests between 

 Li and the bacillary phase have shown that 

 although they share a common antigen, the 

 L phase is deficient in another antigen that 

 is found in the bacillary form (Klieneberger, 

 Jour. Hyg., 42, 1942, 485). Reversion of Li 

 to the streptobacillus form is extremely 

 difficult to obtain on solid media, whereas 

 this reversion generally occurs in fluid or 

 semi-solid media. The stability of Li , even 

 in fluid media, increases with the number of 

 subcultures on solid media. Li cultures are 

 non-pathogenic when reversion to the 

 bacillary form in the inoculated animal is 

 prevented. Vaccines prepared from Li do not 

 protect against infections by streptobacilli 

 (Freundt, op. cit, 1956, 246). 



Relationships and nomenclature of this 

 species : Streptothrix muris ratti Schottmiiller 

 and Haverhillia multiformis Parker and Hud- 

 son are included here as synonyms of Strep- 

 tobacillus moniliformis Levaditi et al. How- 

 ever, because no comparative studies have 

 been made with authentic cultures of these 

 three organisms, the change in nomencla- 

 ture that would be indicated if it were 

 established that these organisms are iden- 

 tical has not been made at this time. 



Source: Isolated from cases of sponta- 



