FAMILY X. LACTOBACILLACEAE 



529 



a nitrogen-containing polysaccharide. Re- 

 ciprocal cross-reactions occur between this 

 group and type I Streptococcus salivarius, 

 thus indicating a similarity in their capsular 

 antigens. Capsular swelling can be demon- 

 strated in the presence of homologous im- 

 mune serum. Rough variants lacking the 

 capsular antigen can be induced by cultur- 

 ing in the presence of homologous immune 

 sera. 



Action on blood: Greening (alpha hemo- 

 lytic) or indifferent (gamma hemolj'tic). 

 The reaction is variable depending upon 

 the type of blood employed. No soluble 

 hemolysin is produced. 



Temperature relations: No growth at 10° 

 or at 45° C. Does not survive 56° C. for 30 

 minutes. 



Tolerance tests : No growth in broth con- 

 taining 6.5 per cent NaCl. No growth at pH 

 9.6. Growth in milk containing 0.005 per 

 cent methylene blue but not in 0.02 per cent 

 methylene blue. Growth on 10 per cent bile 

 blood agar. Maj^ or may not grow on 40 per 

 cent bile blood agar. 



Litmus milk: Acidified and curdled with 

 reduction of litmus after curdling. No di- 

 gestion. 



Final pH in glucose broth, between 4.3 

 and 5.6. 



Produces small colonies on 5 per cent 

 sucrose agar that are fluorescent under 

 ultraviolet light. 



Acid from glucose, maltose, lactose, 

 sucrose and salicin. May or may not fer- 

 ment trehalose. No acid from xylose, 

 arabinose, raffinose, inulin, glycerol, man- 

 nitol or sorbitol. 



Starch, sodium hippurate and gelatin 

 not hydrolyzed. Esculin split. 



Ammonia produced from arginine. 



Comments: This group of streptococci is 

 of particular interest because of its associa- 

 tion with primary atypical pneumonia. Pa- 

 tients recuperating from this disease 

 develop precipitins and agglutinins in their 

 blood against this streptococcus, as well 

 as against Streptococcus salivarius type I. 

 In contrast with other viridans strepto- 

 cocci, this group appears to be particularly 

 resistant to the sulfonamides. 



Source : Saliva, sputum and lung cultures 

 from cases of primary atypical pneumonia. 

 Also found in the respiratory tract of nor- 

 mal individuals. 



Genus III. Pediococcus Balcke, 1884f emend. Mees, 1934.* 



(Balcke, Wochnschr. f. Brauerei, 1 , 1884, 257; Mees, Onderzoekingen over de Biersarcina. 

 Thesis, Delft, 1934, 92.) 



Pe.di.o.coc'cus. Gr. noun pedium a plane; Gr. noun coccus a berry, sphere; M.L. mas.n. 

 Pediococcus plane coccus. 



Cocci occurring singly, as tetrads, pairs or even short chains. Although these organisms 

 are frequently called sarcinae in the literature, packets of eight cells, if they occur at all, 

 are very rare. Non-motile. Gram-positive. Microaerophilic, showing poor surface growth. 

 Generally catalase-negative in sugar media. Homofermentative, producing optically inac- 

 tive lactic acid from carbohydrates. Nitrites not produced from nitrates. Produce acidifica- 

 tion and more or less clouding of wort and beer. Saprophytes in fermenting vegetable juices. 



The type species is Pediococcus cerevisiae Balcke. 



Keij to the species of genus Pediococcus. 



I. Optimum temperature, between 25° and 32°C. Grows in wort, hopped wort and beer. 



1. Pediococcus cerevisiae. 



II. Optimum temperatxire, about 40°C. Grows in unhopped wort but not in beer. 



2. Pediococcus acidilactici . 



* Prepared by Prof. Carl S. Pederson, New York State Experiment Station, Geneva, New 

 York, September, 1954. 



