PFEIFFERELLA WHIT MORI 



493 



Resistance. — Destroyed by moist heat at 56° C. within 10 minutes. Killed within about 

 10 minutes by 1 per cent, phenol and 0-5 per cent, formol. Orj^anisms may survive 

 for a month or more in water, fjeces, and dried soO, and for a week in putrefying 

 carcasses. 



Metabolism. — Aerobe ; very slight growth on agar and in broth after 14 days under strict 

 anaerobic conditions. Optimum temperature for growth 37° C. In culture it 

 grows more rapidly and more abundantly than Pf. mallei. No haemolysis of sheep 

 or horse blood, except perhaps with freshly isolated strains. Tendency to formation 

 of brownish pigment in cultures, especially on potato. Oxalates formed in broth 

 by rough form. 



Fig. 94. — Pf. whitmori. 



Surface colonies onglyccro] agar plate. 



Rough form. 



(After Stanton and Fletcher.) 



Fig. (Jo. — Pf. whitmori. 



Growth on glycerol agar. Left: smooth form. Right: 



rough form. 



(After Stanton and Fletcher.) 



Biochemical. — On first isolation it forms acid, no gas, in glucose, maltose, mannitol, lactose, 

 dulcitol, dextrin, and sucrose ; after long cultivation in the laboratory it may attack 

 glucose only ; Andrade indicator decolorized in 4-10 days. L.M. may be slightly 

 acid in 3 days ; casein is coagulated and may be digested ; partial decolorization 

 of litmus. Indole—; M.R. — ; V.P. — ; nitrates reduced ; NH3 -|- ; HjS J^ 

 when tested by Huddleson's method on liver agar ; M.B. reduction -|- ; catalase -j-. 



Avtigenic Structure. — By agglutination, absorption, and complement fixation cultures of 

 Pf. whitmori form a homogeneous group, which is said to be closely allied to one 

 group of Pf. mallei. 



Pathogenicity. — Causes melioidosis in man, rats, cats, dogs, guinea-pigs, rabbits, and occa- 

 sionally horses. Experimentally, rodents can be infected by feeding, injection 

 into the tissues, or by rubbing on the scarified skin. Produces abscess at site of 

 inoculation, generalized adenitis, and nodular abscesses of the spleen and lungs. 

 After ip. injection of a small quantity of culture into a male guinea-pig, sweUing 

 of the testicles occurs in 2 days with caseous exudate between the two layers of 

 the tunica vaginalis. If a large dose is used, death may occur in 24 hours from 

 septicaemia, before there is time for the Straus reaction to develop or for nodular 

 lesions to appear in the viscera. Small doses prove fatal in about a week. Guinea- 

 pigs are so susceptible that even minute numbers of bacilli brought into contact 



