scholarly journals THE DEVELOPMENT OF THE BACTERIAL FLORA IN THE GASTROINTESTINAL TRACT OF MICE

1965 ◽  
Vol 122 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Russell W. Schaedler ◽  
René Dubos ◽  
Richard Costello

Selective culture media, and equipment for anaerobic incubation of large numbers of specimens, have been developed to facilitate the quantitative enumeration of the various aerobic and anaerobic bacterial species present in the gastrointestinal tract. The evolution of this flora has been followed in young mice from several colonies by cultivating homogenates of the different parts of the gastrointestinal tract at daily intervals from the time of birth to the time of weaning. It has been found that the lactobacilli and anaerobic streptococci become established immediately after birth and persist in large numbers, not only in the large intestine but also in the stomach and in the small intestine. In contrast, the anaerobic bacilli of the bacteroides group become established only after the 16th day; they multiply only in the large intestine but persist in this organ in very large numbers. Other bacterial species become established at different periods of time after birth, exhibit characteristic anatomic localizations, and greatly fluctuate in numbers. In general, the populations of enterobacilli and enterococci decrease precipitously after having reached a maximum level shortly after the beginning of colonization.

1965 ◽  
Vol 122 (1) ◽  
pp. 67-76 ◽  
Author(s):  
René Dubos ◽  
Russell W. Schaedler ◽  
Richard Costello ◽  
Philippe Hoet

The bacterial flora of the gastrointestinal tract differs qualitatively and quantitatively from one colony of mice to another. Certain components of this flora, however, are always present in large and approximately constant numbers in healthy adult mice, irrespective of the colony from which the animals are derived. Lactobacilli and anaerobic streptococci are extremely numerous in the stomach, the small intestine, and the large intestine. In contrast, organisms of the bacteroides group proliferate only in the large intestine. These three bacterial species persist at approximately constant levels in their characteristic localization throughout the life span of healthy animals. They are closely associated with the walls of the digestive organs, and are probably concentrated in the mucous layer. A few experiments carried out with rats and young swine indicate that lactobacilli are also present in large numbers in the stomach of these animal species. It is suggested that some of the components of the gastrointestinal flora have become symbiotic with their hosts in the course of evolutionary development and thus constitute a true autochthonous flora. The other components of the indigenous flora are acquired early in life either through accidental contact or because they are ubiquitous in the environment. The "normal" flora is that which is always present in the environment of the animal colony under consideration.


1965 ◽  
Vol 122 (1) ◽  
pp. 77-82 ◽  
Author(s):  
Russell W. Schaedler ◽  
René Dubos ◽  
Richard Costello

Germfree mice were given food contaminated with pure cultures of various bacterial species isolated from ordinary healthy mice. The cultures were given singly, or in association, or consecutively at weekly intervals. Whatever the technique of administration, the lactobacilli and anaerobic streptococci immediately established themselves throughout the gastrointestinal tract, and became closely associated with the walls of the organs. In contrast, the organisms of the bacteroides group were found in large numbers only in the large intestine. Within a week after exposure, the populations of these three bacterial species reached levels similar to those found in ordinary mice. They remained at these characteristic levels throughout the period of observation (several months). Their presence resulted in a progressive decrease in the size of the cecum which eventually became normal in gross appearance. Coliform bacilli multiplied extensively and persisted at high levels in all parts of the gastrointestinal tract of germfree mice, even after these had become colonized with lactobacilli, anaerobic streptococci and bacteroides. However, the coliform population fell precipitously within a few days after the animals were fed the intestinal contents of healthy pathogen-free mice.


1998 ◽  
Vol 112 (7) ◽  
pp. 634-638 ◽  
Author(s):  
Markus Lilja ◽  
Simo Räisänen ◽  
Lars-Eric Stenfors

AbstractFifty-five samples of pus were collected from 51 acute, non-perforated, two spontaneously ruptured and two recurrent peritonsillar abscesses (35 males and 18 females; median age 18 years) and analysed regarding (i) aerobic and anaerobic bacteria (standard culturing), (ii) morphology of bacteria and inflammatory cells (direct microscopy of acridine orange-stained material), and (iii) the percentage of bacteria coated with immunoglobulins IgG, secretory IgA (SIgA) andIgM and complement cleavage product C3b (immunofluorescence assay). Seventy-one per cent of the abscesses harboured a mixed bacterial flora of various aerobes and anaerobes. In none of the cases with a single bacterial species (27 per cent) could immunoglobulin- or complement-coated bacteria be found. In abscesses with a mixed flora, 18 per cent harboured IgG-coated, 15 per cent SIgA-coated, five per cent IgM-coated and five per cent C3b-coated bacteria, respectively. All pus samples contained inflammatory cells in abundance but they were mostly deformed and only occasionally could intracellular bacteria be recognized. Insufficient immunoglobulin-coating of bacteria might be an important aetiopathogenic factor in the development of a peritonsillar abscess. Bactericide in the abscesses is accomplished chiefly by protective mechanisms not dependent on antigen recognition by antibodies.


1963 ◽  
Vol 42 (2) ◽  
pp. 214-224
Author(s):  
Raymond C. Mellinger ◽  
Jalileh A. Mansour ◽  
Richmond W. Smith

ABSTRACT A reference standard is widely sought for use in the quantitative bioassay of pituitary gonadotrophin recovered from urine. The biologic similarity of pooled urinary extracts obtained from large numbers of subjects, utilizing groups of different age and sex, preparing and assaying the materials by varying techniques in different parts of the world, has lead to a general acceptance of such preparations as international gonadotrophin reference standards. In the present study, however, the extract of pooled urine from a small number of young women is shown to produce a significantly different bioassay response from that of the reference materials. Gonadotrophins of individual subjects likewise varied from the multiple subject standards in many instances. The cause of these differences is thought to be due to the modifying influence of non-hormonal substances extracted from urine with the gonadotrophin and not necessarily to variations in the gonadotrophins themselves. Such modifying factors might have similar effects in a comparative assay of pooled extracts contributed by many subjects, but produce significant variations when material from individual subjects is compared. It is concluded that the expression of potency of a gonadotrophic extract in terms of pooled reference material to which it is not essentially similar may diminish rather than enhance the validity of the assay.


2017 ◽  
Vol 68 (11) ◽  
pp. 2691-2693
Author(s):  
Krisztina Martha ◽  
Cristina Bica ◽  
Edva Anna Frunda

By the end of the 60�s, the theory that refined carbohydrates promotes the absorption of saccharolytic Gram-positive microbial species on the tooth surfaces has become generally. Mutans streptococci (Streptococcus mutans and Streptococcus sobrinus) were key players in this theory. On agar plates, Str. mutans produces small, circular colonies, in the presence of glucose, and in the presence of sucrose large, sticky, gelatinous colonies. This gelatinous texture is due to the shell material: mutant 1 � 3 glucose polymers and dextran 1 �! 6 glucose polymers. Str. mutans are able to survive in the oral cavity with a pH lower than 5.5. That is why consecutive multiple sugar intake promotes the colonization of Str. mutans, which results in dental caries in stagnant zones. As oral pH is continuously shifted to acid, more acid-resistant bacteria appear. Our aim was to identify species in infant-mother pair gingival crevicular bacterial flora, which can be detected on high-sucrose culture media and to underline the jeopardy of vertical oral contamination from mother to infant.


2020 ◽  
pp. 16-18
Author(s):  
V. M. Lykhman ◽  
O. M. Shevchenko ◽  
Ye. O. Bilodid ◽  
Igor Vladimirovich Volchenko ◽  
I. A. Kulyk ◽  
...  

Among urgent surgical diseases of abdominal cavity, an acute intestinal obstruction is the most difficult to be diagnosed and treated. Leading factor, determining the development of pathophysiological processes is considered to be the progressive manifestations of enteric insufficiency syndrome, resulting in intestinal barrier impairment, negative changes in ecology of intestinal flora, increased endotoxins. To identify the small intestine microflora in acute intestinal obstruction and determine the role of dysbiotic disorders in clinical manifestations of main pathological process, a study was conducted in 60 patients with mechanical intestinal obstruction. The small intestine has a relatively rare microflora, consisting mainly of gram−positive facultative aerobic microorganisms, streptococci, lactobacilli. The distal ileum in nearly 30−55 % of healthy people contains scanty microflora, and yet the flora of this area differs from the microbial population of the higher gastrointestinal tract due to higher concentration of gram−negative bacteria. Optional−anaerobic coliform bacilli, anaerobic bifidobacteria and fusobacteria, bacteroids, the number of which starts exceeding the one of gram−positive species, are presented in significant quantities. Distal to the ileocecal valve there are significant changes in the microflora quantitative and species composition. Obligatory anaerobic bacteria become the predominant part of microflora, exceeding the number of aerobic and facultative anaerobic bacteria. The bacterial flora in different parts of gastrointestinal tract has its own specifics and is quite constant, as a result of the interaction of many factors, regulating the bacterial population in small intestine. The most important among them are: acidity of gastric juice, normal peristaltic activity of the intestine, bacterial interactions and immune mechanisms. Disorders of the intestine motor and evacuation function with its obstruction lead to slow passage of the chyme and contamination of the upper gastrointestinal tract with new types of microbes. There is a syndrome of small intestine excessive colonization, which means an increased concentration of bacterial populations in it, similar in species composition to the colon microflora. Pathological intra−intestinal contents become a source of endogenous infection and re−infection of the patient, leads to internal digestive disorders, which is manifested by syndrome of malabsorption of proteins, carbohydrates and vitamins. Key words: acute intestinal obstruction, small intestinal microflora, conditionally pathogenic microorganisms, intestinal biocenosis.


2021 ◽  
Vol 10 (10) ◽  
pp. 2198
Author(s):  
Rosario Musumeci ◽  
Pasquale Troiano ◽  
Marianna Martinelli ◽  
Matteo Piovella ◽  
Claudio Carbonara ◽  
...  

A multicenter, nonrandomized, prospective, controlled study was conducted to evaluate, as perioperative prophylactic treatment, the anti-infective effectiveness of 0.66% povidone-iodine eye drops (IODIM®) against the bacterial flora of the conjunctival surface of patients who undergo cataract surgery. Eye drops containing 0.66% povidone-iodine were applied to the eye undergoing cataract surgery; the untreated contralateral eye was used as control. One hundred and twenty patients set to receive unilateral cataract surgery were enrolled in 5 Italian Ophthalmology Centers and pretreated for three days with 0.66% povidone-iodine eye drops. The contralateral eye, used as control, was left untreated. Conjunctival swabs of both eyes were collected at the baseline visit and after three days of treatment, just before the cataract surgery. A qualitative and quantitative microbiological analysis of bacterial presence was evaluated by means of bacterial culture, followed by identification. Methicillin resistance determination was also performed on staphylococci isolates. Bacterial load before and after treatment of the eye candidate for cataract surgery was evaluated and compared to the untreated eye. A reduction or no regrowth on the culture media of the bacterial load was observed in 100% of the study subjects. A great heterogenicity of bacterial species was found. The 0.66% povidone-iodine eye drops, used for three days prior to cataract surgery, were effective in reducing the conjunctival bacterial load. The 0.66% povidone-iodine eye drops (IODIM®) might represent a valid perioperative prophylactic antiseptic adjuvant treatment to protect the ocular surface from microbial contamination in preparation of the surgical procedure.


1991 ◽  
Vol 20 (8) ◽  
pp. 409-413 ◽  
Author(s):  
Laurie Doyle ◽  
Cynthia L. Young ◽  
Spencer S. Jang ◽  
Sharon L. Hillier

2020 ◽  
Vol 10 (1) ◽  
pp. 1625-1629
Author(s):  
Palzum Sherpa ◽  
Abhimanyu Jha ◽  
Sudhamshu Koirala ◽  
Rojan Ghimire

Background: With increasing usage of endoscopic procedures, gastrointestinal polypoidal lesions are commonly encountered specimens. Histopathological examination is crucial as biological behavior is dependent on its pathological nature. Materials and Methods: A retrospective descriptive study performed in Pathology department, Om Hospital and Research Centre from January 2017 to June 2019. The study included lesions received as polyp or polypoidal lesions of gastrointestinal tract for histopathological examination. Data was analysed using SPSS version 17.0. Gender, number and site were analysed using Chi square test to evaluate its association with neoplastic nature. Correlation with age and size was tested with Pearson’s correlation coefficient. Results: Among 150 cases of gastrointestinal tract polypoidal lesions, 58% were seen in male and 42% in female. Hyperplastic polyp and conventional adenoma were the commonest non-neoplastic and neoplastic lesions respectively. The age of patients ranged from 7 to 84 years with a mean age of 50 years. Rectosigmoid region was the commonest site. 134 patients had single and 16 had multiple polypoidal lesions. Most polypoidal lesion had size <1 cm. Gender, age, number and size showed no correlation with neoplastic nature. A significant association was found with site with notably higher number of neoplastic lesions in large intestine. Conclusion: A spectrum of histological types of polypoidal lesions were found in Gastrointestinal tract, most frequently in colorectal region. Hyperplastic polyp and adenomatous polyp were the commonest non-neoplastic and neoplastic lesions respectively. A notably higher number of polypoidal lesions in the large intestine were found to be neoplastic in nature.


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