Under normal circumstances, microorganisms, hosts and the external environment maintain an ecological balance. If there is an ecological disorder in the three, it is called dysbacteriosis. The bacteria in the intestinal tract of normal people are mainly anaerobic bacteria, and a few are aerobic bacteria. The former is about 100 times that of the latter. The normal flora present in the intestine is Bacteroides, Lactobacillus, Escherichia coli and Enterococcus, and there are still a few pathogens, such as Staphylococcus aureus, Pseudomonas aeruginosa, Para-Escherichia coli, Aerogenes, Proteus, and Clostridium, Candida albicans, etc.

Basic Information

Specialist classification: Digestive examination classification: feces / parasitic examination

Applicable gender: whether men and women apply fasting: not fasting

Tips: Because infants and young children are not easy to get enough samples at a time, if you need to collect them separately, please temporarily store the samples in the refrigerator to avoid bacterial growth. Normal value

There are many bacteria in the feces, accounting for 1/3 of the dry weight, mostly belonging to the normal flora.

Bifidobacteria, Bacteroides, Enterobacter, Enterococcus, Staphylococcus, etc. are mainly found in the stools of healthy infants and young children.

Escherichia coli, anaerobic bacteria and enterococci are the main bacteria in adult feces, accounting for about 80%; gas-producing bacilli, Proteus, and Pseudomonas aeruginosa are mostly pathogenic bacteria, not more than 10%.

Bacillus (such as Clostridium) and yeast, the total amount does not exceed 10%.

The amount of bacteria in the feces and the spectrum are usually relatively stable and maintain an ecological balance with the host.

The ratio of cocci (gram-positive bacteria) and bacilli (gram-negative bacteria) in feces is approximately 1:10.

Clinical significance

Abnormal results:

(1) In patients with long-term use of broad-spectrum antibiotics, immunosuppressive agents, and chronic wasting diseases, the ratio of ball/bacillus in feces becomes larger.

(2) Under certain conditions, some normal bacterial flora can also cause disease, called conditional pathogens, such as cold or excessive fatigue, low resistance.

(3) Gram-negative bacilli are severely reduced or even disappeared, while staphylococcal or fungi are significantly increased, often indicating intestinal flora disorder or double infection. This dysbacteriosis is called pseudomembranous colitis. The smear is often Gram-positive Staphylococcus aureus (cultured as Staphylococcus aureus, Clostridium faecalis, etc.), followed by Candida.

Need to check the crowd:

Intestinal bacterial imbalance patients, long-term abdominal pain symptoms.


Requirements for inspection:

1. The newly prepared dye solution should be tested with known Gram-positive and negative bacteria to check whether the quality of the stain solution is suitable.

2. Please avoid digging the part of the toilet urine and tap water when collecting; do not place the feces directly on toilet paper or paper towels.

3. To avoid interference with the test results, do not use a cotton swab to dig.

4. Do not collect too much feces to avoid having enough specimens for inspection.

5. Crystal violet can not be stored for a long time after mixing with ammonium oxalate solution. If there is precipitation, it should be reconstituted.

6. After the stool inspection, the paper or plastic specimen box should be burned in the incinerator. The enamel container should be soaked in a disinfectant (such as peracetic acid, phenolic soap or chlorpheniramine) for 24 hours. After disposing of the disinfectant, rinse the running water for use. The loaded slides should be immersed and disinfected with 5% phenolic soap.

Preparation before inspection:

1. Because infants and young children are not easy to get enough samples at one time, if they need to be collected separately, please temporarily store the samples in the refrigerator to avoid bacterial growth.

2. Large worms such as mites, mites and mites or their fragments can be distinguished by the naked eye. The hookworm worms must be washed and filtered after the faeces are washed. After the insect repellent, the worms should be inspected for worms and mites. Look carefully at the insect head.

Not suitable for people:

This test is a routine check and there are no unsuitable people.

Inspection process

1. After the stool, use a clean container to take the uncontaminated part of the fecal surface and seal it for inspection.

2. Apply fresh stool directly to a clean glass slide. The feces should not be diluted to prevent bacterial deformation. Specimens should be fresh and smear thick and suitable.

3, microscopic examination: staining technology is the key to accurate diagnosis, Gram-positive bacteria and Gram-negative bacteria should be contrasting. The smear field should be fully viewed during the microscopic examination, and it should not be counted or reported without looking at several fields of view.

4, observe the flora smear first to overview the total number of bacteria. Know if the number of bacteria on the smear is increasing or decreasing, and whether there is a dominant bacteria or fungus. Excessive total bacterial counts are less common or less likely to be taken seriously. When the flora is out of regulation, the total number of bacteria is normal, reduced or disappeared.

Not suitable for the crowd

This test is a non-invasive test, so there is no contraindication.

Adverse reactions and risks

This test is a non-invasive test and the test itself does not present complications and hazards.