434 DESCRIPTION OF SOME SPECIES OF MILK BACTERIA 



BACILLUS TYPHOSUS 



(Eberth, Gaffky). 



Source and habitat — Water, soil, etc., 

 outside the body ; spleen, lymph- 

 glands, blood, urine, excreta, etc., 

 in the body of typhoid patients. 



Morphology — Short plump rods when 

 removed from organs ; longer forms 

 in culture, especially in potato hav- 

 ing acid reaction, i to 3 m long 

 by 0-6 to 0-8 m broad. 



Staining reaction — Ordinary stains ; 

 not by Gram's method. 



Capsule J flagellaj motility — Actively 

 motile ; many (8 to 14) long tortu- 

 ous flagella attached all round 

 capsule of bacillus ; in threads ; 

 serpentine movement. 



Spore formation — No spore for- 

 mation. Vacuole formation is 

 marked, apparent in unstained as 

 well as stained preparations. 



Biology : cultural characters {includ- 

 ing biochemical features') — Grows 

 best at 37° C. on all ordinary 

 media ; grows less well on non- 

 albuminous media ; no pigment 

 production ; no indol. Does not 

 produce gas in lactose media. 

 The amount of acid produced in 

 litmus-whey is very small com- 

 pared with B. coli. 



Bouillon — Turbid growth occurs 

 with abundant sediment. 



Gelatine plates and tubes— Small, 

 yellowish-white punctiform colo- 

 nies ; round, shining ; centre raised ; 

 periphery less opaque. Under 

 magnification indistinct parallel 

 curved lines appear on surface 

 which give the appearance of wavy 

 elevations and surface scratchings ; 

 sometimes limpet-shell characters. 

 In stab-cultures a thread-like, gran- 

 ular, greyish - white growth. On 

 the surface, thin, white, iridescent 

 colony, not elevated, and extending 

 to the glass. In streak culture, the 

 same appearance ; non-liquefying. 



Agar plates and tubes — I rregular, 

 round, greyish-white colonies, shin- 

 ing and slightly raised ; from the 

 centre, dark, yellow, winding, 

 jagged lines extend outward. In 

 stab-culture a thread-like, granular, 

 greyish growth with an irregular 

 surface colony having an oily lustre, 

 and eventually becomes yellowish- 

 grey in colour. On streak culture 

 a moderately spreading growth, 

 wavy, with smooth edge and shin- 

 ing surface ; water of condensation 

 clear with slight precipitate. 



Milk — Is not coagulated ; very 

 little acid is formed. Unchanged 

 appearance. 



Potato — Growth spreads out from 

 line of inoculation as a delicate, 

 moist, " invisible " layer ; not always 

 present ; sometimes a greyish 

 growth, and more rarely a 

 brownish-yellow growth like B. 

 coli. Condition depends upon re- 

 action of potato. 



For methods of differential diag- 

 nosis, see B. coli. 



Anaerobic or aerobic — Growd^ 

 best as aerobe, but also anaerobi| 

 cally and in CO.2. 



Vitality — Retain vitality dried foi 

 months in clothing or soil ; withj 

 stand cold well ; live in water fo 

 a few hours to many days. Maij 

 be retained in the body for sor 

 weeks and even months. 



Pathogenesis — Pathogenic ioi 

 man, produces typhoid fever. 

 Pathogenic for animals, but does 

 not produce typhoid fever, the 

 animal dying of intoxication, not 

 infection. 



BACILLUS VARIANS LACTIS, 

 N08. 1, 2, and 8 (Conn). 



Source and habitat — Milk. 

 Morphology — A bacillus with blunt 

 ends. -S m broad by 1-5 M long. 



