Bacterium Coli Commune

BACTERIUM COLI COMMUNE (Escherich, 1886), has the generally accepted name in Russian medical literature—"intestinal bacillus". According to the taxonomy of the Soc. Amer. Bact., Bact. Committee, 1920, Escherichia coli belongs to the genus Escherichia Castellani and Chalmers (1919), which includes 22 species (Bergey). Bact. coli commune has the form of a short and fairly thick rod, with rounded ends, 1–2 µm in length and 0.4–0.6 µm in thickness, occurring singly and (rarely) in pairs. The rod varies in size within fairly wide limits. Along with coccobacilli, filamentous specimens of bacteria are often encountered. The rod is motile, due to the presence of 4–8 peripherally located flagella (peritrich), shorter than those of typhoid bacteria. Its motility is sluggish. Bact. coli commune stains well with aniline dyes and does not stain by the Gram method. On ordinary nutrient media it grows well in the presence of air, as well as under anaerobic conditions. Its growth optimum is 37°. The broth becomes turbid, does not form a film, and a loose precipitate settles at the bottom of the test tube. The culture has a fecal odor. On agar it forms colonies varying in size and shape; the average diameter of colonies is up to 0.5–1 mm, colonies are flat-

convex, with a smooth or wavy edge, opalescent-turbid, juicy, sometimes surrounded by a mucous border, with a glossy or finely rough surface. Gelatin is not liquefied by Bact. coli commune. Milk coagulates with the formation of acid in it, but does not peptonize it. Coagulation of milk depends on the formation of acid in it and the secretion of rennet enzyme by Bacterium coli commune. In milk serum with litmus it forms acid; it ferments glucose, levulose, lactose, galactose, mannitol, maltose, arabinose, raffinose, sorbitol, dulcitol, salicylin with the formation of acid and gas consisting of a mixture of carbon dioxide and hydrogen. Not all strains decompose sucrose: Bacterium coli communior - decomposes sucrose, and Bact. coli commune does not decompose it. Dextrin is decomposed extremely weakly by intestinal bacillus, and starch is not altered. In broth and peptone water it forms indole; nitrates are reduced to nitrites, ammonia and hydrogen sulfide are secreted. On potatoes, after two days, a grayish or brownish abundant, moist, slightly bumpy deposit is formed. On Endo nutrient medium, colonies of intestinal bacillus are stained fuchsin with a metallic sheen; on agar with milk sugar and litmus, according to Conradi-Drigalski, they change the blue color of the medium to red. The resistance of Bacterium coli commune to external physical and chemical influences does not exceed the average norm for vegetative forms of bacteria, since intestinal bacillus does not form spores. Bact. coli commune, according to Barthlein, forms two main variants: turbid and transparent. In the intestines of humans and animals are found strains of Bact. coli, identical in biochemical properties, but serologically individual. Immune serum, agglutinating that strain with which it was prepared, usually does not agglutinate other strains. Bacterium coli belongs to conditionally pathogenic microorganisms: penetrating into the gallbladder and urinary bladder, renal pelvises and kidneys, it causes inflammatory processes in them. Upon entering the abdominal cavity, usually in a mixture with other intestinal bacteria, it is the causative agent of purulent peritonitis. After death it floods all organs of the corpse, participating in the initial stage of the putrefaction process. Intestinal bacillus is also described as the causative agent of sepsis, suppurations of the pancreas, thyroid gland and almost all other organs, and inflammatory processes in the respiratory tract. Bacterium coli is given significance as the causative agent of enteritis, colitis, summer childhood diarrhea and cholera nostras of adults, but exact evidence in favor of such

The ordinary intestinal bacillus (culture on agar, magnification 1,000). assertion is not provided. Intestinal bacillus is scattered in the nature surrounding humans and animals. Its presence in water indicates contamination of water with fecal masses (details see Water). Quite numerous species of paraintestinal bacteria adjoin Bact. coli commune. Their classification is not exactly established to this time. The most accepted can be considered the classification of Gilbert and Lion, according to which all paraintestinal bacteria are divided into five species, of which No. 1 differs from Bact. coli commune in that it is immotile; No. 2 does not form indole; No. 3 does not ferment lactose; No. 4 does not form indole and does not ferment lactose and No. 5 is immotile, and otherwise similar to species No. 4. Minkiewicz proposes to divide paraintestinal bacteria that do not ferment lactose into four species: 1. Bact. paracoli A, forming acid in milk with litmus; 2. Bact. paracoli B-alkaline-former; 3. Bact. paracoli Aa-acid-former, not forming indole and 4. Bact. paracoli Ba-alkaline-former, not forming indole. The first two species from the scheme of Gilbert and Lion Minkiewicz relates to subspecies of Bact. coli commune. Such a division is practically convenient. The classification of the Association of American Bacteriologists relates paraintestinal bacteria to the genus Salmonella, i.e., to the genus of paratyphoid bacteria. Kruse also proposes to consider paraintestinal bacteria that do not decompose lactose as non-pathogenic subspecies of the paratyphoid group. Such a point of view deserves attention, since paraintestinal bacteria Aa and Ba are identical in their cultural and biochemical properties with Bact. paratyphi A and B, and Bact. paracoli A and B differ from the paratyphoid group only by indole formation. Serologically this group is studied insufficiently, but group agglutinins, common with bacteria of the paratyphoid group, are present in individual strains. The epidemiological significance of paraintestinal bacteria cannot be considered as at all elucidated. The question of the origin of paraintestinal bacteria is decided differently. Barykin and Klyukhin consider them, in particular Bact. paratyphi N, variants of Bact. coli commune. Gruder and Suzuki assert that paraintestinal bacteria represent mutants of Bact. coli commune arising under the influence of bacteriophage; among them pathogenic species may exist. Massini was the first to discover in the group of intestinal bacillus the process of so-called mutation, in which Bact. coli mutabile (=Bact. paracoli No. 3) sheds during growth on solid nutrient media colonies of Bact. coli commune that ferment lactose. The reverse process, i.e., the transformation of Bact. coli commune into Bact. paracoli, does not occur. Intestinal bacillus is always found in the intestine of humans and all warm-blooded animals; it is also found with great constancy in the intestinal canal of cold-blooded animals and some insects. According to Metchnikov, intestinal bacillus, along with other indole-forming microbes, plays a role in the origin of sclerosis and premature aging phenomena. In persons suffering from constipation and digestive disorders, there is a massive reproduction of putrefactive bacteria and intestinal bacillus and intoxication of the organism due to the absorption of toxic products formed during the decomposition of proteins by these bacteria. Experiments of Metchnikov and his employees prove that in the origin of sclerosis of blood vessels special significance should be attributed to indole and skatole, formed in the process of vital activity of this group of bacteria. But the main role of Bact. coli commune in the intestine is reduced to the conservation of the food mash by the acids which it secretes during the fermentation of carbohydrates. In the intestines of children breastfed by the mother, Bact. coli yields the first place to gram-positive lactic acid bacteria; in the intestinal canal of adult humans, predominantly in the large intestines, Bact. coli is the predominant microorganism.