AU589384C - A method of binding microflora - Google Patents

Description

A method of binding microflora and preparations therefor

The present invention relates to a method for microbial colonisation of the oesophagus, stomach and intestines of animals and humans by utilizing bacteria beneficial to the host organism. The invention also relates to a method strengthening the mechanism for adhesion of desired species of bacteria applied. The invention also relates to prepa¬ rations for achieving the results mentioned above.

The invention will be described and is applicable for both animals and humans. "Animals" here relates to domestic animals such as pigs, calves and poultry, such as chickens, turke 's, geese and ducks.

At present the mortality rate amongst the above-mentioned animals is high, and is caused by the establishment and colonisation of pathogenic bacteria in the stomach and in- testines. Pathogenic bacteria out compete the normal bac¬ teria flora, adhere to the wall of the intestines and give rise to symptoms of disease such as diarrhoea, and results in increased mortality. The losses in some herds or flocks are considerable as a result of outbreaks of pathogenic bac- taria as Escherichia ccli, Salmonella typhimurium, Salmo¬ nella sp. , Shi-gella sp. and Clostridium perfringens.

Numerous attempts are currently being made to introduce nonpathogenic bacteria into the gastro intestinal tract in order to prevent or remove colonisation of pathogenic bacteria. Oral administration of different types of ba¬ cillus to humans has been found to reduce the risk of can¬ cer in the large intestine and increase the removal or ousting of intestinal pathogens as well as being of thera¬ peutic value of elderly patients.Equivalent studies of animals and humans have the common factor that bacteria introduced in the gastro intestinal tract in order to

„i„^•»_._"___ - _ . -.. improve the state of health and increase survival in the host organism. Coloτιisation of these bacteria is possible provided the bacteria cells are capable of attaching them¬ selves to the epithelium walls of the host organism.

An almost continuous supply of large bacteria cultures is required to achieve the above results, which makes the me¬ thod impractical .

Most studies of the above type have been carried out on animals and show negative results with respect to adhe- sion and colonisation of the specific type of bacteria used. Existing methods have the following problems,which also prevent successful experiments:

1. Administering bacteria strains of non-specific type which do not exhibit selective colonisation or sur- vival.

2. Administering bacterial strains whose adhesion ability has been investigated and determined in in vitro experiments. The limitation here is that the mechanism for adhesion is not defined and speci- fie (lectinmediated) binding cannot be determined.

Some examples illustrate these limitations:

In pigs:

1. Lactobacillus acidophilus from foodstuff was admini¬ stered in the normal manner. 2. Lactobacillus sp. which had been isolated from the animal was administered orally Colonisation was not obtained in either case.

<r_ ~ In humans:

3. Lactobacillus acidophilus and L. bulgaricus were ad- minstered orally and initially showed favourable re¬ sults, but without colonisation being obtained. The results usually disappeared after 3 days, a decline which accords well with the reduction in the number of Lactobacillus cells in the host organism.

In research into the adhesion of lactic acid bacteria e.g. the genera Lactobacillus and Streptococcus to the gastro intestinal tract in laboratory animals it was found con¬ trary to accepted belief, that the specific binding of the bacteria to epithelial cells in the host organism, is not mediated by polysaccharides, but rather by a protein.

The following points constitute the bases of the process on which the present invention is founded:

a) The mechanism for specific binding of lactic acid bacteria e.g. the genera Lactobacillus and Strepto¬ coccus to the oesophagus and gastro intestinal tract consists of an extracellular protein in the following referred to as adhesive promoting protein (APP) on the bacteria surface. b) The APP is added while simultaneously administering lactic acid bacteria thus increasing the adhesion of bacteria cells. c) Cultivation conditions and treatment of the bac¬ teria for oral administering can be modified to give maximum production of APP. d) The process for efficient production of APP can be applied to other bacterialstrains to be used for co- Ionising the oesophagus and/or gastro intestinal tract.

:ΞT 7

-The invention is illustrated further with reference to the following non-limiting examples, relating to expe¬ riments with animals.

Exampel 1

The cultivation conditions, relating to harvesting and adhesion capacity of lactic acid bacteria were investi¬ gated. The adhesion was determined by an in vitro adhe¬ sion system using bacteria-free portions of the gastro intestinal tract of mice or pigs. The extent of binding of the bacterial cells was determined using both the ra¬ dioactive isotop labeling method as well as light micro¬ scopy and scanning electron microscopy. Adhesion decrea¬ ses markedly with subcultering especially in normally used media for culturing lactic acid bacteria. The addi- tion of elevated levels of saccharides enhanced adhesion by a factor of 3. Brain-heart-infusion media normally contains 0.2% glucose. The bacterial cells show no ad¬ hesion after having been subcultured in complex nutrient On the other hand a defined casamino acid (CAS) medium with the addition of 2% sucrose resulted in lactic acid bacteria having excellent adhesion capacity to the epi¬ thelial cells in the gastro intestinal tract. (Table 1) . Other types of sugar, e.g. glucose and lactose, may be used as well as sucrose. Other amino acid compositions different from the casamino acid may also be used. Bac¬ terial cells cultured in a complex medium could adhere if processsed to preserve APP with cells. This is further illustrated in example 2.

Example 2 The use of the CAS^'mediur. with enhanced levels of saccha¬ rides enabled a proteinaceous compound APP viiich. promotes

adhesion produced by the lactic acid bacteria to be har¬ vested in the supernatant after cultivation. Several pro- teinaceous molecules are released from the bacterial cells during growth in CAS medium with enhanced levels of sac- charides. Proteine fractionation of culture supernatant from lactic acid bacteria grown in CAS-medium, has shown that APP can be identified and isolated.

Once identified this APP was also detected when lactic acid bacteria were cultured in a complex brain heart in- fusion (BHI) broth. The molecular weight of APP has been determined to pproximatly 14000 using a FPLC system by Pharmacia. Bacteria which cannot adhere to the gastro in¬ testinal tract are, however, able to adhere in the presence of this APP. Besides which, a four-fold increase is ob- tained in adhesion of bacteria already possessing an abi¬ lity to bind, when the APP is added. This APP has been demonstrated using hostspecific strains of lactic acid bac¬ teria e.g. the genera Lactobacillus and Streptococcus for tissue from the gastro intestinal tract from both mouse and pig.

Table

Adhesion of Lactobacillus fermentum to mouse stomach, in vitro

Medium Washing of Addition of Adhesion bacteria adhesion promo¬ ting protein APP BHI agar - +

+ - +

BHI broth - - +

" +

" + 2% sucrose - - +++

" + 2% sucrose + - +

BHI broth + + +++

CAS broth + 2% sucrose + + ++++

CAS broth + 2% sucrose + - +

Claims (1)

1. .CLAIMS

   1. A method for increasing the adhesion of bacteria to the stomach and intestines of humans and animals, c h a r a c t e r i s e d in that the bacteria are administered in the presence of an adhesive pro o- ting protein.

   2. A method according to claim 1, c h a r a c t e¬ r i s e d in that the adhesive promoting protein is produced by cultivating bacteria in a defined me¬ dium containing one or more forms of sugars of en- hanced concentration.

   3. A method according to claim 2, c h a r a c t e- r i s e d in that the adhesive promoting protein is produced in vivo.

   4. A method according to claim 2, c h a r a c t e- r i s e d in that the adhesive promoting protein is produced in vitro.

   5. A method according to claim 2, c h a r a c t e- r i s e d in that cultivation is performed in a casamino acid medium or in other a ino acid compo- sitions with the addition of forms of sugars of enhanced concentration.

   6. A method according to claim 2, c h a r a c t e¬ r i s e d in that cultivation is performed in a medium containing sucrose and/or glucose of en- hanced concentration.

   7. A method according to claim 2, c h a r a c t e- r i s e d in that cultivation is performed in a medium with the addition of lactose of enhanced con ceritration. ^"8. A preparation to increase the adhesion of bacteria to the stomach and intestines of humans and animals, c h a r a c t e r i s e d in that the preparation contains and adhesive promoting protein prepared according to claims 2-7.

   9. A preparation according to claim 8 to increase the adhesion of bacteria to the stomach and intestines of humans and animals,c h a r a c t e r i s e d in that the preparation contains non-pathogenic bacteria cultivated in a medium containing sugar types of enhanced concentration for the production of adhesive promoting protein so that the prepara¬ tion contains the adhesive promoting protein formed during cultivation.

   10. A preparation according to claims 8-9, c a r a c ¬ t e r i s e d in that the adhesive promoting pro¬ tein prepared separately is added to the prepara¬ tion.

   11. A preparation according to claims 8-10, to increase the adhesion of bacteria to the stomach and intes¬ tines of humans- and animals, c h a r a c t e r i¬ s e d in that the preparation contains non-patho¬ genic bacteria cultivated in a medium containing sugar types of enhanced concentration for the pro- duction of adhesive promoting protein, and adhesive promoting protein, in combination.

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