Clostridia and clostridiosis - Causes, symptoms and treatment. MF.

Clostridia is a fairly large group of microorganisms, whose representatives are not only the cause of minor health disorders, but also serious infections, the only mention of which is alarming - tetanus, botulism, gas gangrene. Moreover, specific prophylaxis, viz., Vaccination, was developed only in tetanus, while the remaining diseases caused by clostridia can affect various strata of the population, occurring mainly in the form of sporadic cases.

Clostridium

Description of clostridia

Clostridium are gram-positive microorganisms( in the Gram stain they acquire a blue-violet color) belonging to the family Clostridiacae, of the genus Clostridium. The first description of clostridium is dated 1880 by the Polish scientist microbiologist A. Prazhmovsky. They represent sticks with a size of 0.5 to 20 μm, mobile, have different proteolytic activity( the ability to produce enzymes) depending on the species. They are able to form spores, as a result of which they take the form of a "spindle" due to the fact that they are inflated in the center due to the formation of the endospore( it was the Greek word "spindle" that gave their name).The peculiarity of forming endospores allows clostridia to withstand boiling and be inaccessible to antibiotics. Sometimes endospores are located terminal, which gives clostridia the form of "tennis rackets".Clostridia are anaerobes( multiply in the absence of oxygen).

The genus Clostridium includes 100 or more species of bacteria. The most famous of them are C. botulinum( causative agent of botulism), C. tetani( causative agent of tetanus), C. septicum, C. perfringens, C. oedematiens, C. novyi( causative agents of gas gangrene), C. difficile, C. hystoliticum, Csporogenes, C. clostridioforme, C. acetobutylicum, C. colicanis, C. aerotolerans, C. bifermentans, C. tertium, C. piliforme, C. laramie, C. ramosum, C. fallax, C. formicaceticum and others.

Clostridia are widely distributed in nature, can be found in the soil, in water bodies. Some clostridia( for example, C. difficile) are representatives of the normal microflora of certain human body systems, that is, they are saprophytes. Most often they are found in the intestines, on the skin, the mucous membrane of the mouth, the female reproductive system, the respiratory tract. But still the main habitat is the intestine. Normally, in absolutely healthy people, the number of clostridia depends on the age and is: in children under 1 year - up to 103 cfu / g( colony forming units in a gram of feces), in children from 1 year and adults to 60 years - up to 105 cfu / g,over 60 years - up to 106 cfu / g. C. difficile is often sown from soil and water, in which, due to the formation of endospores, it can persist for up to 2 months or more.

Pathogenicity factors for clostridia

The specificity of clostridia and diseases caused by them is the production of toxins and the symptoms associated with them, that is, clostridios - toxicoinfections.

1) Toxin formation is a factor of pathogenicity of clostridia. Some species of clostridia( C. botulinum, C. tetani, C. perfringens) produce one of the strongest bacterial exotoxins( botulinum toxin, tetanus toxin - tetanospasmin, ε-toxin, which destroys erythrocytes).Exotoxins have neurotoxicity( effect on the nervous system), hemotoxicity( on erythrocytes and leukocytes), necrotoxicity( causes tissue necrosis).
2) Another factor of pathogenicity is invasiveness - the ability of local tissue damage due to the development of a number of proteolytic enzymes. In particular, C. perfringens is able to produce proteinase( splitting proteins), collagenase, hyaluronidase. Such aggression factors as proteinase, lecithinase, hyaluronidase, collagenase, are the result of the vital activity of many clostridia species.

The main feature of the pathogenic action of clostridia is the predominance of necrotic processes in tissues over inflammatory, the severity of which is minimal. So, the life activity of clostridia is carried out in anaerobic( without oxygen) conditions and is accompanied by the production of toxins, enzymes and proteins, which determine gas formation and necrosis in tissues, as well as the general toxic effect on the patient's body( most often neurotoxic effect).

Common causes of infection with infections caused by clostridia

The source of the infection may be a patient and carrier, both human and animal, with feces whose clostridia fall into the soil, to the bottom of reservoirs where it can last several months. Mechanisms of infection - alimentary( food), contact-household. Depending on the type of clostridia and the symptoms of the disease, infection of a healthy person occurs through certain transmission factors. Food products( meat products, fruits and vegetables, milk and dairy products) serve as food transfer factors for a number of diseases, for example botulism is products with the creation of anaerobic conditions without preliminary heat treatment( canned food, pickles, smoked products, dried foods, sausageshome cooking).The contact-home mechanism is realized through the wound path of infection, when spores of clostridia of certain species get on the damaged skin. Also, cases of neonatal diseases( in conditions of violation of sterility rules) are described, which happens in tetanus, botulism and other clostridiosis.

Diseases caused by clostridia

Botulism( S. botulinum)
Tetanus( C. tetani)
Gas gangrene( .perrinsens type A,. septicum, C. oedematiens, C. novyi)
Pseudomembranous colitis( C. difficile, perfringens typeA)
Antibiotic Associated Diarrhea( C. difficile)
Necrotizing enteritis, food poisoning( perfringens type A)

Botulism( causative agent of C. botulinum) is an acute infectious disease characterized by the defeat of the nervous system with the development of paresis and paralysis of smooth and striated musculature. The main feature of the pathogen is the ability to produce one of the strongest microbiological poisons - botulinum toxin, which triggers the development of all the symptoms of the disease. More details about this disease in the article "Botulism".

Tetanus( causative agent of C. tetani) is also an acute infectious disease with a lesion of the nervous system and tonic contraction of the muscles of the striated group. This causative agent also has a distinctive feature - the development of a strong toxin - tetanus exotoxin, which causes a severe clinic of the disease. More information about tetanus in the article "Tetanus".

Gas gangrene( causative agents: perfringens type A,. septicum, C. oedematiens, C. novyi) is an infection that develops under anaerobic conditions with the active participation of certain clostridia species that develops in large areas of damaged tissues. Develops after extensive injuries, injuries, traumatic amputations, gunshot wounds. The timing of the appearance of gas gangrene - the first 2-3 days from the time of injury or other serious injury. In the locus of infection, clostridia find favorable conditions for reproduction( lack of oxygen, dead cells and tissues), secrete toxins, causing intoxication of the whole organism and possible damage by toxins of other organs and systems. The patient in the local hearth is observed swelling of tissues, gas formation, necrosis of tissues, the spread of the process to healthy areas. There are several forms - classical, edematous, putrid and phlegmonous. Help the patient to be provided as soon as possible, otherwise the spread of the process can cost the patient a life.

Gas gangrene

Pseudomembranous colitis or PMC( caused more often by C. difficile, but can play the role of and. trringensens type A) .PMC also develops due to antibiotic therapy, often caused by lincomycin, ampicillin, tetracycline, levomycetin, clindamycin, less often cephalosporins. The consequence of this treatment is a rough intestinal dysbacteriosis with a pronounced activity of one of the microbes we are considering - C. difficile. Vital activity of clostridium causes inflammation of the intestinal mucosa, mainly of its distal part, by the formation of so-called "pseudomembranes" - fibrinous raids on the mucous membrane. Such violations threaten the development of complications - perforation of the intestinal wall, which can lead to death. Risk groups for the development of PMC: people of advanced age( over 65 years), as well as people with concomitant diseases( oncology, patients after surgery and others).The patient develops a temperature and intoxication( weakness, headache), however these symptoms are not necessary. Also characterized by a disorder of the stool, which becomes frequent, watery. Weakened patients may experience symptoms of dehydration. The stool can resemble changes in cholera( watery whitish color, frequent and abundant), but in severe cases with a strong pain syndrome, a stool with an admixture of blood may appear.

Endoscopic picture of PMC

Antibiotic-associated diarrhea or AMA( caused by C. difficile,. Perfringens) , but there may be a microbial association with fungi of the genus Candida, Klebsiella, Staphylococcus and others. More often they are registered in conditions of medical institutions among patients requiring antibiotic therapy due to this or that disease. It is under these conditions that forms of clostridia resistant to medicinal preparations are formed. Are observed more often at purpose of preparations of a wide spectrum( cephalosporins, ampicillin and others).There are antibiotic-associated diarrhea due to combined growth inhibition of both pathogenic and saprophytic( quite normal) microflora of the human digestive system. The risk of such a diarrhea is not directly related to the amount of antibiotic in the body( it can occur at the first admission, and with repeated administration of the drug).Risk groups for the development of AMA are patients taking cytotoxic drugs and having immunodeficiency.
Symptoms of AAD are high temperature and intoxication( weakness, malaise), the appearance of a watery stool with pathological impurities( mucus, sometimes blood), pain in the peripodal region, and then along the entire abdomen. When C. difficile is infected, it is not uncommon for a repeat clinic( relapse) after 4-6 days due to the resistance of the clostridium dispute to treatment. In children of the first 3 months, given the small colonization of the intestine and breastfeeding AAD appears rarely.

Necrotic enteritis( caused by: perfringens type F) .Necrotoxin clostridia causes necrosis of the intestinal wall and the formation of erosized surfaces and ulcers( i.e., destruction of the intestinal wall).At the lesion site, inflammatory changes are observed with mucosal edema. There is a danger of bleeding and perforation of the ulcer, as well as the development of thrombosis of small vessels. Patients complain of temperature, vomiting and a loose stool with blood and plenty of foam.

Foodborne disease caused by.perfringens lasts for several days. Clinically, there are few differences from the toxicoinfection of another etiology. Symptoms of the disease are caused by Clostridium toxin and appear in a few hours( usually 6-12 hours) from the time of eating poor-quality food( often meat products).Patients complain of loose stools, nausea, rarely vomiting, tenderness in the abdomen.

Disorders of the genitourinary system. In some cases, clostridia may be the primary cause of the development of acute prostatitis.

Clostridial sepsis can develop with the spread of a large number of toxins in the body and the toxic damage of various organs and systems, including vital organs( kidneys, brain, liver).

Diagnosis of clostridiosis

A preliminary diagnosis is made based on the symptoms of a specific clinical picture, the association of the disease with any extensive trauma, the prescription of antibiotics, the consumption of characteristic foods and the like. The diagnosis is confirmed after laboratory and instrumental diagnostics.

Laboratory diagnostics includes:

1) Bacterioscopy of primary materials for the study.
2) Bacteriological method, in which identification of the pathogen occurs. The material for the study is detachable from wounds, feces and others depending on the clinical form. With sepsis, it can be blood, urine. The material is inoculated into selective culture media( eg, the Kita-Tarozzi medium) and grown under anaerobic conditions.

Clostridia in the

seedlings 3) A biological test for the detection of Clostridium toxins, which uses a neutralization reaction with specific antitoxic sera.
4) Paraclinical methods of investigation( general blood test, urine, coprogram, biochemical blood tests).
5) Instrumental diagnostics. When X-ray examinations can detect gas accumulation in the subcutaneous space and muscle tissue, which is directed to preliminary conclusions about clostridia( gas can be found in other anaerobic infections).With PMC, an endoscopic examination is performed, in which the pattern of focal or diffuse( widespread) colitis is seen with the formation of pseudomembranes.

clostridium difficile under the microscope

Treatment of clostridiosis

Patients with clostridial infections are hospitalized according to indications and severity.
Such diseases as botulism, tetanus, gas gangrene are treated only in the hospital and require immediate help in order to save the life of the patient. Some types of diarrhea are hospital, so they are also treated in a hospital.

Medical assistance includes:

1) Introduction of specific drugs to neutralize toxins in botulism ( anti-butulinic serum, immunoglobulin) and tetanus ( tetanus antiglobal, immunoglobulin).These drugs are subject to careful calculation and staging strictly under the supervision of a doctor in the hospital. Serums are foreign, therefore, there should be a readiness for possible anti-shock measures.

2) Antibiotic therapy , for the purpose of which antibiotics are prescribed, to which the clostridia have sensitivity. These include: nifuroxazide, metronidazole, rifaximin, tinidazole, doxycycline, tetracycline, clindamycin, clarithromycin, penicillin, levofloxacin. The choice of the drug remains only for the treating doctor, who suspected and confirmed the diagnosis of a certain clinical form of clostridial infection. For the treatment of antibiotic-associated lesions of the intestine, the drug that caused this condition is canceled. For etiotropic therapy, vancomycin may be recommended for oral administration, metronidazole.

3) Surgical method of treatment( actual with gas gangrene) and boils down to excision of damaged wound sites followed by antibacterial sanation.

4) Symptomatic treatment depending on the clinical syndrome( probiotics, uroseptics, hepatoprotectors, antipyretic, anti-inflammatory and other groups of drugs).

Prevention of clostridiosis

One of the important rules - careful compliance with personal hygiene rules at home and in the social environment: hand treatment after the toilet, careful processing of food, including thermal. Preventive measures apply to medical workers: monitoring and dynamic monitoring of the appointment of antibacterial drugs, especially to weakened patients of intensive care units, oncohematological hospitals, recipients of organs and tissues.

Doctor infectious disease Bykova N.I.