782 PASTEURELLA 



Horse Blood Agar Plate. — 2 days at 37° C. Good growth similar to that on agar ; no 



haemolysis, but blood plate is slightly cleared and browned. 

 Potato. — 7 days at 22° C. No visible growth. 

 MacConkey Plate.— 5 days at 37° C. No visible growth. 



Resistance. — Very susceptible to inimical agencies ; killed by heat at 60° C. in a few 

 minutes; by 0-5 per cent, phenol in 15 minutes. 



Metabolism. — Aerobe, facultative an- 



• - ^ aerobe. May require low 0-R 



> -, ' potential on first isolation. 



' ^ \ .,..■'.*■ Opt. temp. 37° C, limits 12°- 



;•'.'".'.' " "■'.' 43° C. Growth improved slight- 



" . • « • • ' ly by serum, uninfluenced by 



' . * ' * \ " ' • . . . ■ • glucose, slightly inhibited by 



^ ' '_ ,//,'/'*.. '' . glycerol. No hsemolysis, but 



• \ ' \ y' ,'''.,' »"'■"■. see p. 778. 



' , ^ '' ..''','-. \ ^ > Biochemical. — Acid, no gas, in glucose, 



_ ' * ' XN- - ' "' ' /• /'. ■ ■ mannitol, sucrose, and sorbitol 



'. <•* '/*, *"'"',• 'J - within 14 days ; one type forms 



* - \^: ... ' / • ' acid in maltose. Some strains 



^ - '\ • ', . ^. '. .' "^ produce acid in arabinose, 



'' ^ / ' •'' '' ' '■ xylose, and glycerol. L.M. un- 



' ^' . ' ', .' changed; Indole -f ; M.R. — ; 



- ♦ •" J" ' ,- . ' V.P. — ; Nitrates reduced; 



^' . • ' NH3 very slightly -f- ; M.B. 



Fig. \^\.-Pastmrdla septica. reduction ++ ; H^S + ; Cata- 



From an agar culture, 24 hours, 37° C. ( X 1000). ^^^^ + + " 



Antigenic Structure. — At least two 



types distinguishable by agglutination. Probably one envelope antigen, but more 

 than one somatic antigen. Specific sera agglutinate Past, pestis and Past, pseudo- 

 tuberculosis to a certain extent. Immune sera with protective and curative properties 

 for animals can be prepared by injection of horses with living or dead bacilli. 

 Pathogenicity.^No true exotoxin produced. Virulence subject to alteration. Causes 

 fowl cholera in birds. Other members of this group produce hsemorrhagic septic- 

 aemia in pigs, cattle, sheep, rabbits, mice, rats, reindeer, buffaloes, and other 

 animals. Experimental inoculation reproduces the disease in these animals. 

 Subcutaneous inoculation of a 24-hours' broth culture into a mouse proves fatal in 

 18 to 72 hours. P.M. local oedema and congestion ; often no other signs ; micro- 

 scopically bacilli present in enormous numbers in blood and viscera. If a small 

 dose is given and the animal does not die for 4 to 7 days, there is often a fibrino- 

 purulent pericarditis, a layer of fibrin over the pleura, and partial consolidation 

 of the lungs. Bacilli are numerous in blood and organs. 



PasteureUa pseudotuberculosis 



Synonym. — B. pseudotuberculosis rodentium. 



Isolation. — First observed by Malassez and Vignal in 1883, named B. pseudotuberculosis 

 rodentium by Pfeiffer (1890) in 1889. 



Habitat. — Parasite of rodents, particularly guinea-pigs. 



Morphology. — Small, pleomorphic cocco-bacillus varying greatly in length and shape. 

 Some strains consist of regular ovoid or coccoid organisms, 0*8-2*0 /j, X 0-8 /n, 

 with convex sides, rounded ends, and straight axis ; arranged singly. Other strains 

 consist of rod-shaped organisms, 1-5-5-0 fi X 0-6 jli, with parallel sides, rounded 

 ends, and straight or curved axis ; arranged singly, in groups, or in short chains. 

 Long curved filaments are not uncommon (Fig. 162). Motile in broth cultures at 

 22° C. Non-sporing. Non-capsulated. Ovoid forms show bipolar staining ; rod 



