A Study of the Intestinal Flora under normal and abnormal Conditions

Abstract

(1) Each sample of faeces for these investigations was dried on unglazed porous tiles by the method introduced by Dudgeon. The dried feacal powder was added to the various solid and liquid media used for the aerobic and anaerobic examinations. By this method a large quatity of the faeces was examined, blood agar and boiled blood agar media were used as a routine procedure, and it was unnecessary to employ media which hindered the growth of one organism at the expense of another.(2) It is essential to control the intake of food during the bacteriological investigations of the faecal flora.(3) Among hearlthy individuals, dietetic errors, excess of alcohol, and active purgation may temporarily alter the bacterial content of the faeces and increase the numbers of bacteria present, even to the same extent as among patients suffering from lesions of the intestinal tract.(4) Septic infections of the mouth, throat, respiratory, and urinary tracts may give abnormal bacteriological findings in the faecal flora.(5) Film preparations of the faeces should be made in every instance, but care must be exercised that the correct technique is employed.(6) Experience has shown that several media are essential for the aerobic and anaerobic investigations of the faecal flora in each case.(7) Spirochaetes were found in the faeces in 7 per cent. of the cases and usually in large numbers. There was no evidence to show that they had produced a pathological process in the bowel wall. Short coarse and long delicate spirochaetes occurred. Experience has shown that it is necessary to examine the mouth and respiratory tract in such cases for spirochaetal infection.(8) Streptococci. One hundred and fifteen cultures of streptococci isolated from the faeces in 50 cases of various kinds were investigated. Eighty-two out of the 115 cultures proved to be enterococci. The morphology of this organism is its most striking characteristic. Twenty-one out of the 82 strains were haemolytic, of which 14 were thermostable and 13 acidified mannite. Many strains believed to be haemolytic streptococci were found on more detailed examination to be enterococci.Nineteen strains of long-chained streptococci were isolated, out of which 6 were haemolytic, all were thermolabile, but only 1 acidified mannite.Fourteen strains of medium and short-chained streptococci were isolated.Five of these strains were haemolytic, 2 were thermolabile and 8 acidified mannite.Haemolytic streptococci have been cultivated from the tonsils or sputum with the same cultural reactions and heat resistance as among those found in the patient's faeces, sometimes in large numbers.Streptococci with similar cultural and haemolytic reactions and heat resistance have been cultivated from the faeces of normal individuals and from patients suffering from various infective processes.(9) Haemolytic colon bacilli. These occurred in the faeces under varying conditions in 6 per cent, of the cases, and in most instances were found in abundance. In urinary infections the same haemolytic strains may occur in the faeces and urinary pus. Some cases of toxaemia due to the presence of haemolytic colon bacilli in the faeces in abundance, have improved with specific vaccine treatment to a degree beyond that met with in any other form of intestinal infection.(10) The mucus capsulatus group occurred in 5·5 per cent. of the cases, usually in patients suffering from an abnormal condition. of the intestinal tract.(11) Slow lactose fermenters were cultivated in 2 per cent. of the cases. They have been found occasionally in the faeces of patients suffering from acute urinary fever due to the same bacillus.(12) Staphylococci. The Staphylococcus aureus and albus were present in the faeces in this series in about 35 per cent, in adults. They occurred in large numbers in some cases of diarrhoea, but especially in patients suffering from pulmonary infections, and their presence in the faeces in typhoid fever may be of considerable importance. When staphylococci, especially S. aureus, occur in the faeces in large numbers, or persist as shown by multiple examinations, then it is advisable to examine the patient for an inflammatory focus.(13) Diphtheria-like bacilli were isolated from the faeces in 6 per cent, of the cases. They were larger and coarser than true diphtheria bacilli, but gave a well-marked reaction with one of the modifications of Neisser's stain. They were non-pathogenic to guinea-pigs. Their presence in the faeces appears to be harmless, but they are of importance in children suffering from enlarged tonsils owing to errors of diagnosis which may arise in connection with true diphtheria bacilli.(14) Anaerobes. B. welchii was cultivated from the faeces in 35 per cent. of the total cases. Robertson's heart muscle medium was the most effective for primary culture. Occasionally gangrenous infections due to B. welchii occurred. There was no positive evidence to show, however, that B. welchii produced acute gastro-enteritis, or acute colitis, but its relationship to certain infections and toxaemias is discussed.(15) Three types of intestinal flora are referred to: (1) fermentative or saccharolytic, (2) putrefactive or proteolytic, (3) facultative or normal. The importance of diet in all bacteriological investigations of the faeces is established, while an abnormal faecal flora may be rendered normal by a simple diet. The value of lactose, dextrin, and milk for the treatment of intestinal disorders is fully discussed.(16) Intestinal antiseptics. My observations with so-called intestinal antiseptics has led me to believe that on the whole they are devoid of bactericidal action on the intestinal flora of man. Dimol and colloidal kaolin have been proved to be exceptions in some instances.(17) The pathology of intestinal toxaemia based on the work of the American investigators by means of closed intestinal loops is considered.(18) The characteristics of the acidophilus group of organisms is referred to, including their value in controlling the intestinal flora of man, and for the treatment of intestinal disorders by means of acidophilus milk.

The influence of a diet rich in wheat fibre on the human faecal flora

“…Diet is thought to be one of the main factors controlling the intestinal flora (Dudgeon, 1926), but attempts to alter the flora of adult man by dietary changes have produced disappointing results. Only the feeding of low-residue liquid-formula diets has produced reproducible changes (Attebery, Sutter and Finegold, 1972;Crowther et al, 1973).…”

Ischaemic colitis.

“…Although there is no doubt that the presence of pathogenic clostridia contributes to the speed and severity of bowel necrosis, it is difficult to see how such organisms, which are normal commensals in 35 % of the population (Dudgeon, 1926), gain access to the deeper layers unless the mucosal defences are broken down. It is difficult to avoid the conclusion that in such cases an underlying vascular deficiency permits the invasion of incidentally present Clostridia, which then contribute to the rapid onset of gangrene.…”

Suggested Grouping of Slow Lactose Fermenting Coliform Organisms

“…agar, both black and white colonies develop. Black colonies possess every characteristic of typical coliforms and when transferred to lactose broth produce acid and 20 per cent or more gas in [18][19][20][21][22][23][24] hours. Moreover, cultures established from black colonies breed true and their origin as a variant of a slow lactose fermenting strain can be determined only by serological methods.9 White colonies in 2-5 days show several small, black, daughter colonies within the white parent colony.…”