CHAPTER 17 

 CORYNEBACTERIUM 



Definition. Corynebacterium. 



Gram-positive rod-like forms, arranged usually in a jDalisade. Not acid-fast. 

 Often with club-shaped swelhngs at the poles, generally with irregularly staining 

 segments or granules. Non-motile, non-sporing. Growing aerobicaUy or under 

 microaerophUic conditions, but often capable of anaerobic cultivation. Never 

 formmg gas in carbohydrate media, in which they may or may not produce acidity. 

 They may or may not liquefy gelatin or serum. Some species produce a powerful 

 exotoxin. 



Type species, Corynebacterium diphtheria. 



The generic name Corynebacterium was allotted by Lehmann and Neumann in 

 1896 to the group of bacteria containing the diphtheria bacillus and other species 

 resembling it in morphology. By its derivation the name emphasizes the tendency 

 to the formation of club-like forms that is characteristic of the type species and 

 of several other species within the generic group. This name was accepted by the 

 Committee appointed by the Society of American Bacteriologists (Winslow et al. 

 1920), and was adopted as the valid generic name in the monograph on diphtheria 

 issued under the segis of the Medical Research Council in 1923 (Andrewes et al.). 

 It is gaining increasing currency in the literature and is very unlikely to be super- 

 seded. The summary of the generic characters, as recorded by the American 

 Committee, was emended by the Bacteriological Committee of the Medical Research 

 Council by the omission of aerobiosis as a generic character, the addition of a refer- 

 ence to the fermentative activities of the group, and the omission of any reference 

 to toxin production. There appear to us to be advantages in calling attention to 

 a striking biological character possessed by the type species and perhaps shared 

 by some related species. With the restoration of this reference to toxigenicity we 

 should adopt the summary of generic characters as given by the Committee of the 

 Medical Research Council. 



Although C. diphthericB is universally accepted as the type species, it was not in 

 fact the first to be described. Reymond and his colleagues in 1881, and again in 1883, 

 described the isolation from the conjunctival sac of a bacillus which is now recog- 

 nized, under the name of C. xerosis, as belonging to this genus. This organism was 

 described more fully by Kuschbert and Neisser in the latter year, which also wit- 

 nessed Klebs' description of the diphtheria bacillus in the diphtheritic false mem- 

 brane. It was not until 1884, the year following, that Loeffler published his classical 

 paper on diphtheria, and provided a description of the causative organism which 

 afforded a standard of reference for all subsequent studies on this bacterial group. 

 Any claims that might have accrued to C. xerosis on account of priority would in 

 any case have been vitiated by the fact that it is quite impossible at the present time 



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