596 STREPTOCOCCUS 



In regard to the other groups or species, referred to in the present chapter, 

 we know too little as yet of the variations to which they are subject to attempt any 

 systematic description of them. The description of variants that fit into no general 

 scheme tends to confusion rather than to the clarification of knowledge. We must 

 not, of course, ignore the fact that such variations occur ; but to assess their 

 true significance we must wait until we can allot them their proper place in the 

 picture of bacterial structure, which is being slowly but surely pieced together by 

 modern methods of study. 

 The Anaerobic Streptococci. 



All the species, or groups, of streptococci described above are aerobic and 

 facultatively anaerobic. Cocci growing in short or long chains have, however, 

 been isolated, which are either strictly anaerobic, or grow only under micro- 

 aerophilic conditions. 



These anaerobic streptococci are of considerable importance to the medical 

 bacteriologist, since some, at least, are certainly pathogenic for man ; and the 

 studies of recent years have shown that organisms of this type are a frequent 

 source of severe puerperal infection (see Chapter 66). Apart from puerperal 

 sepsis, and puerperal septicaemia, most of the strains of anaerobic streptococci that 

 have been isolated have been derived from suppurative or gangrenous lesions, 

 which have often been noted as producing a foul or foetid odour (see Veillon 1893, 

 Kronig 1895, Sternberg 1900, Rist 1901, Lowkewicz 1901, Silberschmidt 1902, 

 Marwedel and Wehrsig 1915, Kissling 1924, 1929, Prevot 1924, 1925, 1933). The im- 

 portance of these organisms in relation to puerperal septicaemia was fijst insisted on 

 by Schottmiiller (1910, 1928), though their presence in the genital tract during the 

 puerperium had been noted by several earlier workers. Schottmiiller's observations 

 have since been extended and confirmed by many subsequent observers (Bingold 

 1921, 1932, Lehmann 1926, Harris and Brown 1929, Colebrook 1930, Colebrook and 

 Hare 1933). It would seem (Natvig 1905, Wegelius 1909, Eosowsky 1912, Soule 

 and Brown 1932, White, E. 1933) that these anaerobic streptococci form part of 

 the normal flora of the female genital tract ; and it seems possible (White, E. 1933) 

 that this is their principal normal habitat. Such attempts as have been made 

 to isolate them from the normal human throat or intestine have been unsuc- 

 cessful. 



It is certain that the anaerobic streptococci comprise many different groups, species 

 or types ; but the data available are as yet far too scanty to permit of any systematic 

 classification or nomenclature. Reference to the papers by Prevot, and by Colebrook and 

 Hare, will afford descriptions of several of the strains that have been isolated, and of 

 certain differential criteria on which a future classification may in part be based. 



It may be noted that many of these cocci are very small (0-3-0-4 fx) ; but the size tends 

 to vary considerably in subculture (Colebrook and Hare 1933). Many but not all strains 

 form abundant gas in fluid cultures, diGFermg sharply in this way from the aerobic and 

 facultatively anaerobic species that we have described above. Many, but not all strains 

 produce an extremely foul odour. 



Colebrook and Hare (1933) have studied the growth of 60 strains of anaerobic strepto- 

 cocci on blood agar, and have thus been able to distinguish four different types on the basis 

 of rate of growth, colony form, and changes produced in the medium. Only two of the 60 

 strains produced htemolysis ; three others gave characteristic coal-black colonies. The 

 remaining 55 strains produced no change in the medium. About half the strains tested 

 failed to ferment any test substrate ; with the remainder it was not foimd possible to cor- 

 relate the fermentation reactions with the colonial characters. A prehminary attempt at 



