Proteins (see)

PROTEINS, see Proteins. PROTEUS vulgaris (Hauser), a slender, thin rod morphologically characterized by great diversity; length 1.5–3 µm, width 0.4–0.5 µm; long filamentous as well as spiral forms are encountered. Very motile, provided with numerous long, peritrichous cilia. Gram-negative. Grows well in both aerobic and anaerobic conditions; growth is rapid. In broth—marked turbidity, abundant sediment. On the surface of agar—delicate granular colonies; their shape is irregular, bizarre due to "swarming." Similar "swarming colonies" with the formation of peripheral offshoots, growths, bay-like depressions, etc.—on gelatin; the picture, however, is quickly smoothed out due to energetic liquefaction of the gelatin. On potato—scanty growth in the form of a yellowish glossy deposit. Decomposes glucose and sucrose with the formation of gas. Forms indole (not always). Belongs to the number of putrefactive microbes, energetically decomposing protein with the formation of foul-smelling gases (ammonia, hydrogen sulfide). A strong alkali producer. Possesses hemolytic properties. Outside the organism, Proteus is found in rotting meat (see Meat poisoning) and other putrefying objects; it is also found in water contaminated with putrefying substances. It is a permanent inhabitant of the human intestine, in which it takes part in putrefactive processes. It is found in greater numbers in children suffering from diarrhea than in healthy ones, and according to Mechnikov, it is one of the causative agents of children's diarrhea. It is found in severe catarrhs of the bladder and in other urinary tract disorders, as well as in phlegmons, otitis, etc., accompanying other microbes. Close to P. vulgaris are: P. mirabilis, characterized by a lesser ability to liquefy gelatin and sharply expressed morphological diversity; P. Zenkeri, which does not liquefy gelatin and is almost indifferent with regard to proteins; P. piscicidus versicolor, which is the causative agent of fish disease, etc. Of the greatest importance among the varieties of Proteus vulgaris is Proteus X₁₉ of Weil-Felix. This microbe was isolated from the urine of typhus patients and is characterized by the fact that it is strongly agglutinated by typhus serum, which is why it has very great diagnostic significance (see Weil-Felix reaction). Felix and Weil distinguish two forms of Proteus X₁₉: the H-form, which produces "swarming," and the O-form, deprived of this trait and forming isolated, mucous colonies. The question of the significance of Proteus X₁₉ is not resolved; some, based on the constancy of the Weil-Felix reaction in typhus, consider this microbe to be the causative agent of this disease; others see in the Weil-Felix reaction a para-agglutination, viewing the relationship between the typhus virus and Proteus X₁₉ from the standpoint of para-infection and para-immunity. The latter opinion, substantiated experimentally, is the most probable (see Para-agglutination and Para-immunity).