Shigella dysenteriae (Shigella dysenteriae)

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07.12.2021

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Shigella is an anaerobic, gram-negative bacteria that causes dysentery. They belong to the Enterobacteriaceae family. There are 4 species, divided into serogroups:

• Shigella Flexnera;
• dysenteric shigella;
• Shigella Zone;
• Shigella Boyd.

Detailed description of the study

Shigellosis, or dysentery, is an acute intestinal infection, which is accompanied by intoxication of the body and damage to the gastrointestinal tract, mainly the distal parts of the large intestine. The causative agent of the disease is bacteria of the genus Shigella. Based on their properties, they are divided into 4 groups (Flexner/S. flexneri, Bodie/S. boydii, Dysentery/S. dysenteriae, Sonne/S. sonnei), each of which has several types.

The source of infection is humans. The mechanism of transmission of the pathogen is fecal-oral. Bacteria enter the body with contaminated food or water in the stomach, and then enter the small and large intestines, where they penetrate cells, release a toxin and cause inflammation, including the formation of ulcers on the mucous membrane. The toxin acts on nerve endings, causing spasms and pain, as well as on blood vessels, leading to circulatory disorders. The toxin has not only a local effect, but also a general one - a person develops intoxication.

The incubation period is 2-3 days. The disease begins with increased body temperature, weakness, lethargy, nausea, and pain in the lower abdomen. The stool becomes frequent, liquid, mixed with blood. Then the person feels sharp, nagging pain in the lower abdomen and rectal area, a urge to have a bowel movement with a slight discharge in the form of mucus and/or blood, and sometimes a complete absence of discharge (the so-called false urge to defecate, tenesmus). A gastroenteric variant is also distinguished, which is characterized by more significant damage to the upper gastrointestinal tract, accompanied by profuse vomiting and frequent bowel movements in the absence of severe damage to the colon.

Dysentery can become chronic (more than three months). It can be continuous when symptoms progress with deep damage to the gastrointestinal tract. In this case, no significant intoxication is observed, but the person suffers from constant abdominal pain and diarrhea. With a recurrent course of the disease, periods of exacerbation alternate with phases of remission. The chronic course of shigellosis is more typical for people with reduced immunity.

Also one of the forms of the disease is bacterial carriage. It is characterized by the absence of clinical signs during and three months before the examination, while Shigella is detected in the stool.

Shigellosis can have adverse effects, especially in children. After infection with Shigella Flexner, in 2-4% of cases, reactive inflammation of the joints (arthritis), eye damage (conjunctivitis) and inflammation of the urethra (urethritis) are possible. Timely detection and treatment of shigellosis helps to avoid its complications.

To diagnose dysentery, bacteriological methods (isolation of the pathogen), PCR (DNA determination) and serological (determination of antibodies in the blood) are used.

When bacteria enter the body, protective antibodies are formed against them - immunoglobulins. IgM is produced at the onset of the disease, and IgG - at later stages. Determination of antibodies in the blood to Shigella (serology) is an auxiliary diagnostic method, especially indicated in the case of a negative bacteriological test result, if shigellosis remains suspected. The analysis allows us to detect total antibodies of both classes to Shigella Flexnera serotypes 1-5. This study must be carried out dynamically, with the first analysis carried out, for example, upon admission to the hospital (best from the 5th day of the disease), and then 7–10 days after the first study. The diagnosis is confirmed by an increase in the titer (level) of antibodies by at least 4 times.

general characteristics

The shape of bacteria can be compared to rods, which have rounded ends and no flagella. Standard parameters are 0.5-0.7 by 2-3 microns. There is no ability to create capsules with spores.

The peculiarity of Shigella is its minimal resistance to chemical, physical, and biological action from the outside. Having settled on objects or products, dishes, they live no more than 14 days. Instant death occurs at +100 degrees.

If we talk about direct sunlight, it neutralizes bacteria within 30 minutes. With its deficiency and excess moisture, Shigella caught in the soil can live up to 3 months. Once in the gastric juice, they are destroyed within a few minutes. But in frozen or dried feces, organisms exist for up to several months.

The bacteria were named after a Japanese microbiologist. It was Kiyoshi Shiga, who in 1897 identified the organisms that represent Shigella dysenteriae today.

What else is prescribed with this study?

Clinical blood test with leukocyte count and ESR (with microscopy of a blood smear to detect pathological changes) (venous blood)

3.9.1. Ven. blood 1 day

460 ₽ Add to cart

Coprogram

21.2. Feces 1 day

360 ₽ Add to cart

Culture for intestinal pathogens (Shigella spp., Salmonella spp.)

123.0. Feces, smear 4 days

650 ₽ Add to cart

Culture for yersinia (Yersinia spp.)

132.0. Feces 12 days

650 ₽ Add to cart

Shigella, Escherichia, Salmonella, Campylobacter, DNA (Shigella spp., E. coli (EIEC), Salmonella spp., Campylobacter spp., PCR) feces, quality.

19.53. Feces 2 days

850 ₽ Add to cart

Dysentery

All Shigella provoke the development of bacterial dysentery. The pathology affects the distal part of the large intestine and is accompanied by intoxication. The bacterium is transmitted through household contact and the fecal-oral method, through food and water. The main carriers are cockroaches and flies.

The infection is accompanied by a dull pain in the abdominal area, which turns into cramping attacks in the lower zone. Defecation is accompanied by nagging pain, shooting into the sacrum. Its frequency at first is 10-25 times per day. The masses are filled with blood and mucus, and later pus appears.

Shigellosis incubation usually lasts up to 7 days and is accompanied by the following symptoms:

• headache;
• severe fever with convulsions;
• severe malaise;
• heat;
• frequent vomiting.

Recovery is noted after 3 weeks. In a certain group of patients the disease becomes chronic.

Treatment of dysentery

Effective therapy for the disease involves the use of the following drugs:

• ciprofloxacin of the antibiotic group, taken for 3 days in a dosage approved by the attending physician;
• Alternative antibiotics include pivmecillin - up to 5 days of use in individual doses, ceftriaxone - up to 5 days.

When determining a medication for the treatment of dysentery, the results of drug sensitivity tests regarding the Shigella strain are taken into account.

There are a number of antibiotic drugs that in practice demonstrate high activity against Shigella. These are furazolidone, rifaximin, oflaxacin, etc. If we talk about josamycin, it is effective against certain types of Shigella. It is important to remember that such bacteria demonstrate resistance to roxithromycin.

Classification according to ICD-10

For the described shigillosis, represented by different types, a three-character heading has been conditionally created. It contains the following subspecies:

• A03.0 - pathology caused by Shigella dysenteriae, belongs to group “A” and is called Shiga-Kruse dysentery;
• A03.1 – disease with a pathogen in the form of Shigella flexneri, group “B”;
• A03.2 – a disease caused by the bacterium Shigella boydii, belongs to group “C”;
• A03.3 – disease from Shigella sonnei, group “D”;
• A03.9 – unspecified form of shigillosis.

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Shigella dysenteriae (Shigella dysenteriae)

Shigella dysentery

(lat.
Shigella dysenteriae
, generally accepted abbreviation
Sh. dysenteriae
) is a type of bacteria that causes dysentery.
The incorrect spelling Shigella disenteria
.

Systematics of Shigella

Shigella dysenteriae (lat. Shigella dysenteriae
) is one of four species of the genus Shigella (
Shigella
), which is part of the family Enterobacteriaceae (lat.
Enterobacteriaceae
), order enterobacteria (lat.
Enterobacteriales
), class gamma-proteobacteria (lat.
γ proteobacteria
), type proteobacteria (lat.
Proteobacteria
), kingdom of bacteria. Shigella species are considered to coincide with their respective serogroups. All types of Shigella (and this, in addition to Shigella dysentery, also Boyd's Shigella, Flexner's Shigella and Sonne's Shigella) are causative agents of dysentery. Shigella dysentery has been classified into 12 serotypes.

Previously, the following names for the various serotypes were used:

• Shigella dysentery Sh.
  dysenteriae serotype 1 - Grigoriev-Shigi rods
• Shigella dysentery Sh.
  dysenteriae serotype 2 - Stutzer-Schmitz rods
• Shigella dysentery Sh.
  dysenteriae serotypes 3–7 - Large-Sachs rods

Shigella dysenteriae. general information

Shigella dysentery is a facultative anaerobic, spore- and capsule-forming, gram-negative, nonmotile bacteria.
They have a size of approximately 2–3 by 0.5–0.7 microns. Shigella dysentery is the least resistant species of Shigella to external factors. Shigella dysentery instantly dies when boiled; when heated to 60 °C, Shigella dysentery dies within 10 minutes. At the same time, they can survive for a long time in milk and dairy products, fruits and vegetables, and survive for some time in the soil, in cesspools and polluted open water bodies.

Shigella dysenteriae - the causative agent of dysentery

Shigella dysenteriae ( Sh. dysenteriae
) was the most common cause of bacillary dysentery (also called shigellosis) until the 1930s. Currently, other representatives of the Shigella genus are taking first place - Flexner's Shigella and Sonne's Shigella. Shigella dysentery is a common cause of dysentery epidemics, especially in crowded populations such as refugee camps.

Shigella infection occurs only through the mouth. Once in the stomach, part of the Shigella dies under the influence of gastric acid, and endotoxin is released, which is absorbed in the intestine and, entering the blood, has a toxic effect on the body. Some Shigella reach the colon, where, as a result of their proliferation, inflammation occurs, including the formation of ulcers.

Household infection occurs through direct contact with a patient, through the contaminated hands of a patient or a bacteria carrier, or household items. During the warm season, food products become contaminated by flies, which carry microscopic fecal particles containing Shigella. Consumption of contaminated products that have not been subjected to heat treatment (milk and dairy products, salads, vinaigrettes, pates, vegetables, fruits, berries, etc.) can cause collective diseases of shigellosis. The possibility of such outbreaks increases if a patient with dysentery or a bacteria carrier is directly involved in the preparation and distribution of food. Infection can occur when using water contaminated with bacilli-carrying feces from open water bodies or when swimming in them. Serotype 1 Shigella dysentery produces an exotoxin - Shiga toxin (named after the discoverer of Shigella, Japanese physician and microbiologist Kiyoshi Shiga), which causes intoxication of the body, sometimes very severe. Shiga toxin acts on the walls of blood vessels, the central nervous system, peripheral nerve ganglia, the sympathetic-adrenal system, the liver, and the circulatory organs. Mortality from dysenteries caused by shigella dysenteriae

can reach 5–15%.

See also: “Advice from the American College of Gastroenterology for Food Poisoning” (translation into Russian of a release published in the United States on June 3, 2011 in connection with infection in Europe)

, recommendations of Rospotrebnadzor: “On the prevention of food poisoning and infectious diseases transmitted by food”, WHO recommendations “Guide to safe food products for tourists”.

On the website GastroScan.ru in the “Literature” section there is a subsection “Constipation and Diarrhea”, containing professional medical articles, including those related to bacterial diarrhea and their treatment.

Shigellosis incidence statistics

According to official data, the number of registered cases of bacterial dysentery (shigellosis) in the Russian Federation for 2009 and 2010, including among children and adolescents under 17 years of age inclusive, is as follows:

Complete statistics on bacterial dysentery diseases (shigellosis) in Russian regions for 2009 and 2010 are available here: general, children and adolescents up to 17 years of age inclusive.
The total number of registered cases of shigillosis (bacterial dysentery) in Russia: in 2013 - 11,897, in 2014 - 10,747, in 2015 - 10,001, in 2021 - 9,655.

Treatment of dysentery caused by shigella

For the treatment of shigella dysentery, WHO recommends (“Treatment of diarrhea.” 2006):

• as the antibiotic of choice - ciprofloxacin 500 mg twice a day for adults, 15 mg per kg of body weight twice a day for children, taken for three days
• as alternative antibacterial agents:
• pivmecillin 400 mg 4 times a day for adults, 20 mg per kg of body weight twice a day for children, taken for five days or
• ceftriaxone - in children 50-100 mg per kg body weight intramuscularly for 2-5 days

Antibiotics active against Shigella dysentery and not recommended for use in the treatment of shigellosis

Antibacterial agents (those described in this reference book) active against Shigella dysentery: furazolidone, nifuroxazide, ciprofloxacin, doxycycline (not all strains).
WHO recommends that the following antimicrobial agents (including some of those listed above) should never be used to treat shigella dysentery: metronidazole, streptomycin, tetracyclines, chloramphenicol, sulfonamides, amoxicillin, nitrofurans (e.g. nitrofurantoin, furazolidone), aminoglycosides (e.g. gentamicin, kanamycin), first and second generation cephalosporins (eg, cephalexin, cefamandole) and considers ciprofloxacin the drug of choice (“Treatment of diarrhea.” WHO, 2006).

Shigella dysenteriae in ICD-10

Shigella dysenteriae
is mentioned in the International Classification of Diseases ICD-10 in “Class I. Some infectious and parasitic diseases”, in which in the block “A00-A09 Intestinal infections” there is a heading “A03.0 Shigellosis caused by
Shigella dysenteriae " with the decoding that it is " Shigellosis group A [Shiga-Kruse dysentery].” Back to section