FAMILY X. LACTOBACILLACEAE 



545 



Habitat: Undoubtedly widely distril)uted 

 in milk or milk products. 



3. Lactobacillus helveliciis (Orla-Jen- 

 sen, 1916) Holland, 1920. (Bacillus e, von 

 Freudenreich, Cent. f. Bakt., II Abt., /, 

 1895, 173; also see Landw. Jahrb. d. Schweiz, 

 1895, 211; Bacillus casei e, von P'reudenreich 

 and Thoni, Landw. Jahrb. d. Schweiz, 1904, 

 526; Thermobacterium helveticiun Orla-Jen- 

 sen, Maelkeri-Bakteriologie, 1916, 35; also 

 see The Lactic Acid Bacteria, 1919, 164; 

 Holland, Jour. Bact., 5, 1920, 223.) 



hel.ve'ti.cus. L. adj. Helveiicus Swiss. 



Rods, 0.7 to 0.9 by 2.0 to 6.0 microns, oc- 

 curring singly and in chains. Non-motile. 

 Gram-positive. 



Whey gelatin colonies: Does not grow 

 readily at temperatures required for incu- 

 bation of gelatin. 



Lactose agar colonies: Small, grayish, 

 viscid. 



Milk: Acid, with coagulation; may be- 

 come slimy. 



Acid from glucose, fructose, galactose, 

 mannose, maltose and lactose; smaller 

 amounts are produced from dextrin. The 

 lactic acid produced is optically inactive. 



Nitrites not produced from nitrates. 



Microaerophilic. 



Temperature relations: Optimum, be- 

 tween 40° and 42° C. Minimum, between 

 20° and 22° C. Maximum, 50° C. 



Source: Isolated from sour milk and 

 cheese. 



Habitat: Widely distributed in dairy 

 products. 



4. Lactobacillus acidophilus (Moro, 

 1900) Holland, 1920. (Bacillus acidophilus 

 Moro, Wiener klin. Wochnschr., 13, 1900, 

 114; also see Jahrb. f. Kinderheilkunde, 52, 

 1900, 38; Holland, Jour. Bact., 5, 1920, 215.) 



a.ci.do'phi.lus. L. adj. acidus sour; M.L. 

 neut.n. acidum acid; Gr. adj. philus loving; 

 M.L. adj. acidophilus acid-loving. 



Description of Moro supplemented by 

 material from Kulp and Rettger (Jour. 

 Bact., 9, 1924, 357), Curran, Rogers and 

 Whittier (Jour. Bact., 25, 1933, 595) and 

 Rettger, Levy, Weinstein and Weiss (Lacto- 

 bacillus acidophilus, Yale Univ. Press, New 

 Haven, 1935). 



Rods, 0.6 to 0.9 by 1.5 to 6.0 microns, oc- 

 curring singly, in pairs and in short chains 

 with rounded ends. Non-motile. Dimensions 

 variable (Kulp and Rettger), (Curran, 

 Rogers and Whittier). Gram-positive; old 

 cultures often Gram-negative (Moro). 



Gelatin: No growth at 20° C. No lique- 

 faction. 



Wort-agar (Moro) or tomato agar (Kulp 

 and Rettger) plates. Surface colonies: pe- 

 ripheries a capilliform maze of long, deli- 

 cate, twisted, fuzzy projections; center 

 appears as a thick, dark, felt-like mass. 

 Deep colonies: small, irregularly shaped, 

 with fine radiate or ramified projections. 



Wort-agar slants: Growth scant, limited, 

 dry, veil-like. 



Wort-broth: After 48 hours, fine, floccu- 

 lent sediment. Other acid broths sediment 

 whitish, slight turbidity. 



Milk: Slow growth with small inoculum. 

 Coagulates from the bottom up. 



Potato: No growth. 



Acid but no gas from glucose, sucrose and 

 lactose (Moro). Acid from glucose, fructose, 

 galactose, mannose, maltose, lactose and 

 sucrose. Some cultures ferment raffinose 

 and trehalose and have slight action on 

 dextrin. Xylose, arabinose, rhamnose, glyc- 

 erol, mannitol, sorbitol, dulcitol and inosi- 

 tol not fermented (Kulp and Rettger). Op- 

 tically inactive lactic acid and volatile acids 

 formed from sugars (Curran, Rogers and 

 Whittier). 



No visible growth in carbohydrate-free 

 media (Rettger, Levy, Weinstein and 

 Weiss). 



Microaerophilic. 



Temperature relations: Optimum, 37° C. 

 No growth between 20° and 22° C. (Moro). 

 Maximum, between 43° and 48° C. (Curran, 

 Rogers and Whittier). 



Not pathogenic for laboratory animals. 



Distinctive characters: Grows in acid 

 media. Unless frequent transfers are made, 

 organism may become Gram-negative and 

 rapidly develop characteristic degeneration 

 forms (Moro). The so-called original strains 

 of Bacilhts acidophilus from the Krdl col- 

 lection, described and called Microbaclerium 

 lacticum by Orla-Jensen, do not have the 

 characteristics given by Moro. 



Comments: Crecelius and Rettger (Jour. 



