Escherichia coli

“ It is not possible by the result of the experiments upon animals to decide whether the bacterium coli was cultivated from a pure or infected water, and the discovery of a virulent bacterium coli in any sample of water cannot, therefore, be regarded as a criterion that such water has been polluted with fæcal bacteria. ”

“ For intervention studies (other than the provision of an improved source, for example the protection of unprotected springs) , estimates could be based on either the baseline or control group; when both were available we used whichever had the largest sample size. For studies reporting both E. coli and TTC, we used only the E. coli results. ”

“ Bile Salt Broth (page 180) combines these desiderata; it permits only the growth of intestinal bacteria, whilst the formation of an acid reaction and the production of gas in subcultures prepared from the germ-germicide mixture is fairly complete evidence of the presence of living B. coli.
The amount of medium present in each test-tube is a matter of importance, since the medium not only provides pabulum for the test germ, but also acts as a diluent to the germicide, to reduce its strength below its inhibition coefficient. For routine work each subculture tube contains 10 c.c. ”

“ Data Extraction and Matching
Where possible we extracted or calculated the following information for each type of water source in the studies: (i) total number of samples and proportion containing E. coli or TTC; (ii) proportion of samples within microbial risk categories (<1 or not detected, 1–10, 10–100, and >100 E. coli or TTC per 100 ml) ; (iii) geometric mean, mean, or median levels of E. coli or TTC; and (iv) risk categories according to the sanitary inspection (“low,” “medium,” “high,” and “very high” risk) as reported in the studies. ”

“ There is also a peculiar fermentator, Bacterium coli, that refuses to meddle with milk-sugar alone, but upon the addition of white of egg shows extraordinary activity, furnishing lactic, formic, and acetic acid. These three—Bacterium aceti, Bacillus subtillis, and Bacterium coli—are the normal visitants [3] of milk, and the changes dependent upon their presence are well understood. The microorganisms that breed disease and death appear under exceptional circumstances, against which, so far as they are known, we may carefully guard. ”

“ At the height of the spring floods the raw water contained 80 p.p.m. of turbidity and over 500 B. coli per c.cm. but 0.6 p.p.m. of chlorine and 0.13 p.p.m. of ammonia reduced the B. coli index in the tap samples to 2.5 per 100 c.cms.; samples taken in Hull on the same day (treated with 0.7-0.8 p.p.m. of liquid chlorine) gave a B. coli index of 26.7. Previous experiences in Ottawa has shown that a dosage of approximately 1.5 p.p.m. of available chlorine is required to reduce the B. coli index to 2.0 per 100 c.cms. under similar physical and bacteriological conditions. ”

“ In practice no attempt is made, except in special cases, to destroy the spore-bearing organisms as they have no sanitary significance and the concentration of chlorine required for their destruction would cause complaints as to tastes and odours if the excess of chlorine were not removed. Such doses are unnecessary and result in waste of material. It is found that, when the dose is sufficient to eliminate the B. coli group from 25-50 c.cms. of water, the majority of the residual bacteria are of the spore-bearing type. ”

“ The facts themselves by their remarkable variety have not aided classification. Names which a few years ago were applied to individual species, like Bacillus subtilis, or Bacterium termo, or Bacillus coli, are now representative, not of individuals, but of families and groups of species. Again, isolated characteristics of certain microbes, such as motility, power of liquefying gelatine, size, colour, and so forth, which at first sight might appear as likely to form a basis for classification, are found to vary not only between similar germs, but in the same germ. ”

“ There is no evidence of any marked difference in the resistance of ordinary water bacteria to chlorine and these are the first to be affected by the added germicide. The common intestinal organisms are also very susceptible to destruction by chlorine and there is considerable evidence that B. Coli is slightly more susceptible than many of the vegetative forms usually found in water. The specific [53] organisms causing the water-borne diseases, typhoid fever and cholera, are, on the average, not more resistant than B. coli. ”

“ In the next stage ammonia is formed by the tryptic enzymes secreted by the ærobic bacteria, and so the anærobic organisms are enabled to develop. We can thus understand how it is that putrefaction proceeds more rapidly the more mixed ferments there are present, although these were formerly supposed to hinder putrefaction from taking place.
When meat is exposed to air it is first attacked by the mixed ferments, Micrococcus flavus liquefaciens, Staphylococcus, Bacillus coli, Bacillus filiformis, Streptococcus and Diplococcus, and becomes acid ”

“ Determine the lowest percentage of germicide-x which inhibits growth of B. coli in the bile salt broth, and the highest percentage which fails to inhibit (page 311) . On the result of this experiment determine the bulk of medium required in the subculture tubes and the percentage solutions to be employed in the trial trip. Assuming the inhibition coefficient to be 1:1000, it will be quite safe to employ the ordinary culture tubes containing 10 c.c. medium in the subsequent experiments. ”

“ To harmonize this well-established fact with modern views on the cause and nature of the suppurative process, it has been suggested that, though in these sterile abscesses micro-organisms had originally been present, they had subsequently died out. This view receives a measure of support from the fact that in a proportion of instances there is no difficulty in demonstrating in the pus the ordinary pyogenic bacteria and, sometimes, the Bacterium coli commune. ”

“ Mixed peptolytic ferments are only able to attack the albumin when it has undergone a preliminary decomposition. This group comprises B. coli, B. filiformis, Streptococcus pyogenes, Diplococcus griseus non liquefaciens.
The second class of bacteria are those which are without action on carbohydrates, and only attack proteids; these consist of the true proteolytic bacteria B. putrificus, and B. putidus gracilis, and the peptolytic bacteria, Diplococcus magnus anaerobius and Proteus zenkeri, which can only decompose peptones. ”

“ Plate Culture. The milk is to be diluted a thousand or229 more times with sterile water, and ordinary plate cultures made in Petri dishes or flat-bottomed conical flasks. The colonies should be counted as late as possible; but even then the isolation of pathogenic germs is uncertain. As regards further procedure, the ordinary methods of sub-culturing adopted in water examination must be strictly followed, and the special tests for Bacillus typhosus and B. coli applied. As we have already seen, the quantitative estimation of organisms in milk is not of the same value as in water. ”

“ Its motility is in varying degree, occasionally being as active as B. typhosus, but generally much less so. It possesses lateral flagella. On gelatine plates at 20° C. B. coli produces non-liquefying, greyish-white, round colonies; in a stroke culture on the same medium, a luxuriant greyish band, much broader and less restricted to the track of the needle than B. typhosus. In depth of medium or "shake" cultures there is an abundant formation of bubbles of gas (methane or carbon dioxide) in the medium. ”

“ A number of the strains that survived several treatments were cultivated in lactose broth and the acidity determined quantitatively. All the cultures produced less acid than the original culture, and the average was materially less than the original. These results point to a diminution of the bio-chemical activity by action of the chlorine.
A point of perhaps more scientific interest than practical utility is the relative proportion of the various types of B. coli found before and after treatment with chlorine. ”

“ In milk this is a comparatively small group, for it happens that those bacteria in milk which cannot be classified as fermentative or pathogenic are few. The almost ubiquitous Bacillus coli communis occurs here as elsewhere, and might be grouped with the gaseous fermentative organisms on account of its extraordinary power of producing gas and breaking up the medium (whether agar or cheese) in which it is growing. What its exact rôle is in milk it would be difficult to say. It may act, as it frequently does elsewhere, by association in various fermentations. ”

“ There is no spore formation, and, consequently, the culture soon dies unless inoculated into a fresh nutrient medium. The liquor, after the fermentation both in the drenches and tubes of pure cultivations, is always slightly ropy.
B. furfuris probably belongs to the group of coli bacteria, some of which ferment milk and other sugars with production of lactic acid and gases. This explains the ease with which the fermentation takes place, since the skins bring in immense numbers of bacteria from the bate, among which are the organisms described. ”

“ The fæces from a man contain on an average perhaps 1,000,000,000 bacteria per gram, [47] most of them being the normal bacilli of the intestines, Bacillus coli communis. Assuming that a man discharges 200 grams or about 7 ounces of fæces daily, this would give 200,000,000,000 bacteria discharged daily per person. The number of bacteria actually found in American sewage is usually higher, often double this number per person; but there are other sources of bacteria in sewage, and in addition growths or the reverse may take place in the sewers, according to circumstances. ”

“ Bacillus coli communis, which, though not now considered absolutely indicative of alimentary pollution, is looked upon as a highly unsatisfactory inhabitant of water, has been found in considerable abundance. The Proteus family, which also possesses a putrefactive function, is common in ice-creams. The common water bacteria are nearly always present.
Bacillus typhosus itself, it is said, has been isolated from some ice-cream which was held responsible for an outbreak of enteric fever. ”

“ The organisms isolated from sewer air are those commonly present in the open air. Micrococci and moulds predominate, whereas in sewage bacilli are most numerous. Liquefying bacteria, too, which are common in sewage, are extremely rare in sewer air. Bacillus coli communis, which occurs in sewage from 20,000 to 200,000 per cc., is altogether absent from sewer air. ”

“ An organism which has exceptional opportunities for finding its way into cows' milk is the Bacillus coli communis, normally present in the fæces of all animals. This microbe is a very undesirable adjunct to milk, and may greatly interfere with the souring process, by multiplying extensively, and so producing a change in the milk which renders it impossible for the particular souring bacteria to carry on their work, resulting in their collapse and ultimate extinction. ”

“ It resembles closely the Bacillus coli communis, which is an almost constant inhabitant of the alimentary canal, and is held by many bacteriologists to play, especially in conjunction with yeasts and other saprophytic organisms, an active rôle in the intestine of man.
In a recent official report59 Dr. Hope, of Liverpool, states that "the method of feeding plays a most important part in the causation of diarrhœa; when artificial feeding becomes necessary, the most scrupulous attention should be paid to feeding-bottles." ”

“ These strains of E. coli do not appear to be pathogenic in pigs that do not permit colonization. Edfors-Lilja et al. (1986) were able to demonstrate that pigs which had receptors for E. coli F4+ (K88) had a lower rate of preweaning growth, indicating that their performance was suffering due to their susceptibility to the pathogen. However, the pigs displayed compensatory gain during postweaning growth periods. Since resistance/susceptibility to both pathogens was clearly defined and controlled by single genes, scientists have identified the regions of the genome which possess both genes. ”

“ Bacterium coli no longer a true criterion of sewage pollution. It may be convenient to point out in this place that bacterium coli can no longer be looked upon as a typical inhabitant of the human intestines after the very elaborate investigations carried out by Dr. ”

“ In the centre of the nucleus is a chromatinic body or karyosome or sometimes several small nuclear bodies formed of plastin and chromatin; the remaining chromatin is arranged on the achromatic network in the form of fine granules, especially thickly deposited on the nuclear membrane.
Entamœba coli lives as a commensal in the upper portion of the large intestine, where the fæces still possess a pulpy consistency. With their concentration and change in reaction lower in the bowel, the parasites either die or else if they are at a suitable stage of development form resistant cysts. ”

“ It was found that typhoid, cholera, and various other bacilli were most deleteriously affected by insolation. Perhaps an example will best serve to illustrate the nature of the results obtained. Some boiled water contained in a flask was inoculated with an immense number of a bacillus, closely resembling the typhoid organism, normally present in the body and frequently found in water, the bacillus coli communis. So many were introduced that nearly one hundred thousand individuals were present in every twenty drops of the water. ”