Bacteriological examination of feces

One of the methods of laboratory diagnostics is a bacteriological examination of human vital products, including feces. Such an analysis is usually included in both general preventive examinations and complex narrow-profile diagnostic measures. In the biomaterial processed in a special way, some important indicators of the state of health are determined, for example, the presence of intestinal dysbacteriosis or intestinal infections, and based on the results of the analysis, the quality of the treatment provided can be monitored. Such an analysis can be prescribed to patients of any age.

What is the intestinal microflora for?

It is well known that in the human intestine there is a large number of various microorganisms, in total more than 500 species. Most of the microflora “live” in the large intestine, a smaller amount – in the small intestine and appendix.

Although, at first glance, it may seem that their functional significance for humans is not particularly important, in fact, the activity of these bacteria is directly reflected in the health of their carrier.

In the intestinal cavity, bacteria attach to the villi of the epithelium. One of their functions is the production of a special mucous biofilm, which is responsible for maintaining the population of beneficial microorganisms and protecting them from external influences.

In the course of their life activity, bacteria actively multiply, participating in the processes of digestion of food and the assimilation of nutrients by the human body.

In case of ingress of foreign microorganisms, “strangers” are destroyed, forced out, or their adaptation takes place, and they also begin to participate in the general life of intestinal bacteria.

In addition to the functions described above, microorganisms in the intestine perform other tasks – they break down and digest food, protect the epithelial inner layer of the intestine, participate in metabolic processes, synthesize certain vitamins and amino acids, form immune system reactions, protect against various pathogenic organisms.

At the same time, part of the microbiota of the intestine itself is opportunistic, such as E. coli. In normal quantities, it is an active participant in the processes of digestion.

Any change in the quantitative or qualitative ratio of microflora in the intestine leads to a deterioration in health.

Bacterial composition of the intestinal microflora

All microorganisms that inhabit the intestinal cavity are, for convenience, classified according to whether they can pose any danger to their carrier under certain conditions.

Thus, distinguish:

• saprophyte bacteria that function in the intestines and do not harm the carrier: lactobacilli, bifidobacteria, escherichia;
• conditionally pathogenic microorganisms that can provoke the development of certain pathological processes under certain conditions: clostridia, staphylococci, candida, enterococci;
• pathogenic, which are the causative agents of dangerous diseases: salmonella, shigella.

What is it for?

Analysis of feces for intestinal infections and dysbacteriosis allows you to identify all types of microorganisms, including pathogens. The essence of the study is to sow the excretions of the body on nutrient media, as a result of which all the bacteria present in the feces begin to multiply intensively and are easily identified either by the nature of growth or microscopically with special staining. Often, a study, which is also called stool culture, is prescribed for children.

Based on the results of the analysis, the attending physician receives information about the presence of deviations in the work of the intestines, the causes of digestive disorders, the imbalance of microflora, the presence of parasites and helminths in the intestines.

Indications and contraindications for stool culture

The study of fecal masses is prescribed in cases where the doctor needs additional information about the patient’s health status. Indications for the appointment of bacteriological examination of feces are:

• the need for antibiotics;
• pregnancy planning;
• the presence of digestive problems: constipation, diarrhea, heartburn, nausea and vomiting, heaviness in the stomach:
• stomach ache;
• increased gas formation;
• completed a course of antibiotic treatment;
• manifestations of allergic reactions;
• frequent infectious diseases, suspicion of the presence of helminths;
• diagnosed oncological diseases;
• immunodeficiency.

As for possible contraindications, this procedure does not have them – bacteriological examination of feces can be carried out at any age and in any condition of the patient.

Requirements for sampling material for analysis

Carrying out a bacteriological analysis of feces requires some preparatory measures from the patient. Fecal masses are a product of the vital activity of the human body, which is influenced by the nature of its nutrition.

Therefore, in order to ensure the most objective diagnosis, it is recommended, first of all, to consult with your doctor and, approximately 5-7 days before taking feces for pathogenic intestinal flora, refuse to take antibiotics, anti-diarrhea drugs, anthelmintic drugs, laxatives, enzyme-containing and iron-containing drugs. It is not recommended to do cleansing or therapeutic enemas for 3-4 days. The doctor should be warned about all medications taken shortly before the analysis. If the subject visited other countries half a year before the analysis, this should also be reported to the doctor.

As part of the preparation of the patient, 2-3 days before the scheduled date for the test, you should follow a diet that excludes foods that increase gas formation or stain the feces. Forbidden:

• beans;
• beet;
• raw vegetables and fruits;
• bread and confectionery;
• milk and dairy products;
• greenery;
• tomatoes;
• red fish.

When compiling a diet during this period, it should be remembered that eating meat can also affect the results of the analysis. It is not allowed to take feces for analysis, which is obtained using laxatives or enemas. All these recommendations are relevant for the planned sampling of material.

How is the collection of material for analysis by the patient

There are several ways to take feces for research. In the first case, the patient collects biological material for study on his own, after an arbitrary defecation process. In this case, there are some requirements for the fence technique.

It is necessary to take care in advance of the availability of a special sterile container for the collected feces – in any pharmacy you can buy a container with a tight-fitting lid and a spatula.

It is very important that foreign impurities do not get into the feces sent for analysis – urine, menstrual flow, cleaning products from the toilet bowl. Women are advised to collect material after the end of menstruation.

If there is pus or mucus in the stool, they must be collected. Blood blotches or clots should not be collected for analysis. The bladder must be emptied before sampling.

For analysis, a mass of about 2-3 teaspoons is sufficient, while choosing the material from different parts of the mass – from the inside, from the sides, from above.

Having collected material for research in a container, it must be tightly closed with a lid. On the container, you should indicate your last name and initials, date of birth. Within no more than one and a half hours, the container with the contents must be delivered to the laboratory. Most often, special storage conditions cannot preserve the fecal microflora as much as possible, since most of the bacteria that enter it die upon contact with oxygen. Five hours after sampling, the material is no longer suitable for research.

Taking feces for analysis in a laboratory or hospital

In some cases, the sampling of material for research is carried out by a medical professional, regardless of the process of the patient’s natural defecation. For this, tampons or special loops can be used. This algorithm for taking feces is also suitable for young children.

The stool sampling technique looks like this: the subject lies on the couch, in the “on his side” position, bending his knees and pulling his hips to his stomach. He needs to spread his buttocks with his palms. To a depth of 10 centimeters, a loop or swab is inserted into the anus, with which the nurse carefully removes the contents of the intestine from the wall of the rectum.

The collected material is placed in a sterile test tube, container or container with a preservative. Without a preservative, the material must be processed no later than 2 hours after its withdrawal.

How is the further processing of feces

After collecting the material for analysis, it is sent in a sterile container to the laboratory, where the sample is sown as quickly as possible on a solid colored nutrient medium – Levin’s medium or bactoagar Zh, as well as on an accumulation medium (Kaufman, Muller). The crops made for a day are sent to a thermostat, where they are kept at a temperature of 37 degrees Celsius. If the stool was collected on a swab, it is applied to a cup with a solid colored medium and scattered with a spatula. A day later, the material is ready for research.

Technique for bacteriological and coprological examination of feces

Clinical analysis of feces includes their initial examination. At the same time, its structure, color, consistency, smell are studied. Normally, feces should not contain pieces of undigested food, mucus, pus, be discolored or, conversely, too dark.

Biochemical analysis involves carrying out some chemical reactions, for example, reactions to the presence of bilirubin, occult blood, starch, fatty acids, protein, iodophilic flora. All these elements should normally show a negative reaction result.

Reactions to ammonia and stercobilin should be positive. Using a litmus indicator, the pH of the feces is determined. In addition, the material is examined under a microscope. This method of studying feces allows you to identify the presence of pathological elements in the excrement. Fecal microscopy provides an opportunity to assess the quality of food digestion, to diagnose cystic fibrosis, dysbacterial and enzymatic disorders.

Bacteriological examination of feces is an analysis due to which it is possible to reveal the presence of a number of pathologies in a patient, including dysbacteriosis. Normally, the intestinal microflora is a balanced symbiosis of various types of microorganisms that are responsible for the functioning of the immune system, for the process of food processing, for maintaining a normal level of acidity and protective resources of the body. The danger of dysbacteriosis is that this destroys the intestinal microflora, as a result of which a person may develop serious diseases caused by pathogenic microflora.

In addition to dysbacteriosis, this type of diagnosis reflects the nuances of the digestive process of the subject, the state of his intestines and stomach. Fecal analysis is an opportunity to determine the presence of bleeding in the digestive organs.

The identification of pathogenic agents allows the diagnosis and confirmation of infectious diseases, which improves the possibility of applying specific therapy.

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