876 



CLOSTRIDIUM 



Potato. — 14 days at 30° C. No definite growth visible on the potato itself, but theie is 



a considerable evolution of gas from the liquid in which the potato is soaked ; the 



liquid is turbid. 

 Metabolic. — Obligate anaerobe. Opt. temp. 30-40° C. Pigment none. Nutritional : 



grows best in sugar solutions. Growth on agar improved by 1 percent, mannitol. 



Non-proteolytic. 

 Biochemical. — Forms acid and gas in dextrose, laevulose, maltose, galactose, lactose, 



sucrose, inulin, dextrin and starch. Fermentation of mannitol variously reported. 



Indole — ; M.R. + ; V.P. — ; nitrates reduced ; M.B. reduction — ; catalase — ; 



NH3 slight + ; L.M. acid and clot. Can fix atmospheric nitrogen in presence of 



a fermentable sugar ; the sugar is broken down with the formation of butyric 



and acetic acids, CO2 

 source of nitrogen. 

 Pathogenicity. — Nil. 



and Hg. Can utihze NH3, peptone, and asparagin as its 



Clostridium sporogenes 



Isolation. — Described by MetchnikoflP in 1908. 



Habitat. — Found in soil, and in faeces of man and animals. 



MorpJwlogy. — Rod-shaped, 3-6 /i X 0*5 



fi, parallel sides, rounded ends, 



axis straight or slightly curved, 



^ arranged singly, in pairs, and 



- y small groups ; long filaments 



occasionally formed. Spores 



.\ 



,t 





Fig. 193. — Clostridium sporogenes. 



From a surface agar culture anaerobically, 2 



days, 37° C. ( X 1000). 



Fig. 194. — Clostridium sporogenes. 



Surface colony on agar anaerobi- 

 cally, 4 days, 37° C. ( X 8). 



freely ; spores are oval, subterminal, and wider than bacillus ; free spores numer- 

 ous. Motile. No capsule. Strongly Gram-positive, except in old cultures. 



Agar Plate. — 4 days at 37° C. Irregularly round colonies, growing from a central focus like 

 B. mycoides ; 2-6 mm. in diameter, effuse or slightly umbonate, and rhizoid ; 

 surface covered by arborescent ridges, edge rhizoid ; rather dull, greyish-yellow 

 by reflected, bluish-grey by transmitted light ; butyrous and easily emulsifiable ; 

 differentiated into brownish opaque centre and bluish translucent periphery. 



Deep Glucose Agar.— 4: days at 37° C. Abundant gas formation ; medium driven 

 to plug and disrupted. Colonies throughout medium ; rounded, 0-5-2 mm. in 

 diameter, with opaque brown centre and a woolly translucent periphery. 



Horse Blood Agar. — 3 days at 37° C. Colonies 3 mm. in diameter, consisting of tangled 

 rhizoids growing from a raised, gUstening centre, 0-5 mm. in diameter ; on moist 



