FAMILY XII. CORYNEBACTERIACEAE 579 



II. Live primarily on decomposing organic matter. Saprophytic. 



A. Found primarily in dairy products. Acid production weak. Lactic acid is the prin- 

 cipal acid produced. Xon-motile. 



Genus IV. Microbnderium, p. 600. 



B. Found primarily in soil. 



1. Decomposes cellulose. Motile and non-motile species. 



Genus V. Cellulomonas , p. 601. 



2. Does not decompose cellulose. Generally non-motile. Gram-negative rods occur 

 in j'oung cultures, and coccoid, Gram-positive cells develop in older cultures. 



Genus VI. Arthrobacter , p. 605. 



Genus I. Corynebacterium Lehmann and Neumann, 1896.* 

 (Bakt. Diag., 1 Aufl., 2, 1896, 390.) 



Co.ry.ne.bac.te'ri.um. Gr. noun coryne a club; Gr. noun bacterium a small rod;M.L. 

 neut.n. Corynebacternim club bacterium. 



Straight to slightly curved rods with irregularly stained segments, sometimes granules. 

 Frequently show club-shaped swellings. Snapping division produces angular and palisade 

 (picket fence) arrangements of cells. Non-motile with exceptions among the plant pathogens 

 as stated in the text. Gram-positive, sometimes young cells and sometimes old cells losing 

 the stain easily. Granules invariably Gram-positive. Generally quite aerobic, but micro- 

 aerophilic or even anaerobic species occur. Catalase-positive. May or may not liquefj^ gela- 

 tin. May or may not produce nitrites from nitrates. May or may not ferment sugars, but 

 seldom, if ever, is a high acidity produced. Many species oxidize glucose completely to CO2 

 and H2O without producing visible gas. Some pathogenic species produce a powerful exo- 

 toxin. This group is widely distributed in nature. The best known species are parasites and 

 pathogens on man and domestic animals. Other species have been found in birds and even 

 in invertebrate animals. Several species are well known plant pathogens while still other 

 common species are found in dairy products. 



The type species is Corynebacterium diphtheriae (Fliigge) Lehmann and Neumann. 



Key to the species of genus Corynebacterium. 



1. AEROBIC TO FACULTATIVELY ANAEROBIC. 



I. From animal sources. f Non-motile. 

 A. From vertebrates. 

 1. Acid from glucose. 



a. Attack man and frequently other animals. 

 b. Nitrites produced from nitrates. 

 c. Indole not produced. 



1. Corynebacterium diphtheriae. 

 cc. Indole produced. 



2. Corynebacterium enzymicum . 



* The human section of this genus was revised by Prof. E. G. D. Murray', University of 

 Western Ontario, London, Canada, the animal section by Dr. E. V. Morse, Department of 

 Microbiology and Public Health, College of Veterinary Medicine, Michigan State Uni- 

 versity, East Lansing, Michigan, the plant section by Prof. Walter H. Burkholder, De- 

 partment of Plant Pathology, College of Agriculture, Cornell University, Ithaca, New 

 York and the anaerobic section by Dr. H. Seeliger, Hj^giene-Institut der Universitat 

 Bonn, Germany, November, 1954. 



t Habitat relationships are used in this key because comparative studies of the species 

 in these groups are still completely lacking. 



