CHAPTER XVIII 

 MALTA OR MEDITERRANEAN FEVER 



Micrococcus Melitensis (Bruce) ; Bacillus Melitensis (Babes) 



General Characteristics. — A non-motile, non-flageUate, non-sporogenous, 

 non-chromogenic, non-liquefying, pathogenic coccus, staining by the ordinary 

 methods, but not by Gram's method; characterized by remarkably slow growth 

 and by pathogenic action upon monkeys. 



In 1877, while working in Malta, Bruce* succeeded in finding in 

 every fatal case of Malta fever a micrococcus which could be isolated 

 in pure cultures from the spleen, liver, and kidney, which grew read- 

 ily on artificial media, and which, when injected into monkeys, pro- 

 duced the disease. 



Morphology. — Micrococcus melitensis, as Bruce called it, is a 

 round or sUghtly oval organism measuring about 0.3 m in diameter. 

 It is usually single, sometimes in pairs, but never in chains. When 

 viewed in the hanging drop it is said to exhibit active "molecular" 

 movements, but is not motile and has no flagella. Babes f declares 

 it to be a bacillus. 



Staining. — It stains well with aqueous solutions of the. anilin dyes, 

 but not by Gram's method. 



Thermal Death Point. — ^This has been fixed by Dalton and Eyre J 

 at s7.s°C. 



Cultivation. — The best medium for its cultivation is said to be 

 ordinary agar-agar. After inoculating, by a puncture, from the 

 spleen of a fatal case of Malta fever, the tubes should be kept at 

 37°C. The growth first appears after several days, in the form of 

 minute pearly white spots scattered around the point of puncture 

 and along the needle path. After some weeks the colonies grow 

 larger and join to form a rosette-like aggregation, while the needle 

 tract becomes a sohd rod of yellowish-brown color. After a lapse of 

 months the growth still remains restricted to the same area and its 

 color deepens to buff. 



When the sloping surface of inoculated agar-agar is examined by 

 transmitted light, the appearance of the colonies is somewhat 4if- 

 ferent. At the end of nine or ten days, if kept at 37°C., some of the 

 the colonies have a diameter of 2 to 3 mm. They are round in form, 

 have an even contour, are slightly raised above the surface of the 

 agar-agar, and are smooth and shining in appearance. On examining 



"Practitioner," xxxiv, p. 161. 

 tKolle and Wassermann, "Die Pathogene Mikroorganismen," m, p. 443. 

 t "Jour, of Hygiene," 1904, iv, p. 157. 



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