FAMILY CORYXEBACTERIACEAE 



39' 



yellow chromogenesis more readily. 

 This, however, does not appear to have 

 occurred any more frequently than took 

 place with the authentic culture of Bac- 

 terium fimi when tested by Jensen {loc. 

 cit.). 



23. Corynebacterium tumescens Jen- 

 sen. (Jensen, Proc. Linn. Soc. New So. 

 Wales, 59, 1934, 45.) From Latin tumes- 

 cens, swollen. 



Rods show characteristic cytomorpho- 

 sis in glucose agar, Sabouraud's (whey) 

 agar and milk agar. Cells after IS to 24 

 hours at 28° to 30°C are curved, often 

 branched, show an angular arrangement. 

 0.5 to 0.8 by 2.5 to 6.0 microns. After 2 

 to 3 days many spherical to club-shaped 

 cystites (3 microns in diameter) arise as 

 local swellings of the rods. Staining in- 

 tensely at first, they gradually change 

 into large, irregular, poorlj- stained ghost 

 cells which show deeply staining belts 

 and granules. Irregular less swollen 

 deeply stained rods and small cocci (0.4 

 to 0.5 micron) which resemble the gran- 

 ules in the cj^stites are also present. 

 These cocci are living cells. Non-motile. 

 Gram-positive. 



Gelatin colonies: Small, opaque, yel- 

 low. Liquefaction after 3 to 4 weeks. 



Milk agar: C\ystites develop in almost 

 pure cultui-e. These sometimes have 2 to 

 4 small cocci attached to the wall so that 

 they look like budding yeasts. When 

 transferred to fresh agar, cystites either 

 fail to grow or germinate with 2 to 4 slen- 

 der germ tubes which regenerate the rods. 

 Cystites are produced most abundantly at 

 37°C, sometimes not at all at 16° to 18°C. 



Sabouraud's agar : Cystites sometimes 6 

 to 8 microns in diameter. Growth may 

 be cream-colored or even grayish-pink. 



Asparagine agar: Growth thin, flat, 

 moist, colorless. 



Broth : Faint uniform turbidity ; after 

 2 to 3 weeks, a soft white to cream-colored 

 sediment. 



Milk: Thin white ring around surface. 

 Soft coagulation after 18 to 20 days. 

 Later, slow digestion. Faintly acid. 



Potato : Slow but eventually good 

 growth, restricted, glistening, viscid, 

 cream-colored to grayish-orange. 



Acid from glucose, arabinose, galactose, 

 maltose and glj'cerol ; occasionally from 

 sucrose and mannitol. 



Nitrites produced from nitrates. 



Optimum reaction pH 6.2 to 6.8. 



Slimy variants produced after 172 days 

 growth in lithium solution. 



Source : Two strains from grass soils and 

 one from garden soil in Australia. 



Habitat: Soil. 



24. Corynebacterium simplex Jensen. 

 (Proc. Linn. Soc. New So. Wales, 59, 1934, 

 43.) From Latin simplex, simple. 



Rods : 0.4 to 0.5 by 3.0 to 5.0 microns, 

 curved and in parallel bundles. No 

 branching in older cultures but the 

 cells grow shorter, becoming almost 

 eoccoid. Angular arrangement. Non- 

 motile. Gram-positive. 



Gelatin : Colonies very small . Filiform 

 growth along stab. Liquefaction after 4 

 days. 



Asparagine agar : Fair to good growth, 

 becoming moist and glistening. No pig- 

 ment . 



Glucose agar : Abundant growth. 

 Spreading, smooth, glistening, cream- 

 colored to grayish-j-ellow. 



Broth : Uniform turbidity, grayish- 

 yellow, viscid sediment. 



Milk: Yellowish ring around surface. 

 No coagulation. Complete digestion 

 after 10 to 12 days. Reaction neutral. 



Nitrites produced from nitrates. 



Starch is not hydrolyzed. 



Acid from sucrose. Alkaline reaction 

 in other sugar broths. 



Excellent growth at 37°C. 



Resembles Corynebacterium fdamento- 

 sum in cultural characters but does not 

 form long filaments. 



Source : From grass soil and red soil 

 from Griffith, Australia. 



Habitat : Soil. 



25. Corynebacterium filamentosum 

 Jensen. (Proc. Linn. Soc. New So. 



