What is Campylobacteriosis?
Campylobacteriosis is a group of infectious animal and human diseases characterized by varying degrees of severity and polymorphism of manifestations.
Brief historical information
The first pathogens in patients with diarrhea were discovered by T. Escherich (1884). The possibility of their circulation in the patient’s blood is proved by Zh.G. Vincent (1947). The etiological significance of microorganisms in the development of enteritis in humans was noted by E. King.
Since the beginning of the 80s of the 20th century, domestic and foreign researchers have paid attention to the relatively high level of diarrheal diseases of the population caused by Campylobacter (over 8%).
Causes of Campylobacteriosis
The causative agents are microaerophilic gram-negative motile spore-forming bacteria of the Campylobacter genus of the Campylobacteriaceae family. In accordance with the latter classification, the Campylobacteriaceae family includes 2 genera, Campylobacter and, in addition, Arcobacter. Campylobacter is represented by helical (may have one or more coils), S-shaped or curved cells. When cultivated for more than 48-72 hours, they form coccoid forms. Bacteria are whimsical to cultivation conditions. They are usually grown on blood media supplemented with various inhibitors of the growth of the contaminating flora. The optimum pH is 6.2-8.7, the temperature 42 ° C. The cultivation atmosphere should contain at least 10-17% C02. Nine species of Campylobacter are known, but C. jejuni, C. coli, C. lari and C. fetus of the subspecies fetus are most important in human pathology. Less commonly, diarrhea in humans is caused by C. hyointestinalis, C. upsaliensis, C. sputorum of the subspecies sputorum. The overwhelming majority of cases of campylobacteriosis in children and adults is C. jejuni. Most cases of generalized and septic forms of extraintestinal campylobacteriosis cause C. fetus subspecies fetus. Of the four Arcobacter species, A. cryaerophilus group 1 B and A. butzleri have clinical significance.
Campylobacter is sensitive to drying, prolonged exposure to direct sunlight. In fresh water at a temperature of 4 ° C, they survive for several weeks, at 25 ° C – 4 days, in the soil and bird droppings – up to 30 days. When heated to 60 ° C, bacteria die after 1 min; boiling and chlorinating water causes their quick death. Campylobacter is sensitive to erythromycin, chloramphenicol, streptomycin, kanamycin, is not sensitive to penicillin, resistant to sulfonamides and trimetaprim.
The reservoir and source of infection are wild and farm animals and birds, in which, in addition to the disease, carriage is possible. The role of wild animals and birds in the spread of infection is less significant, however, it was found that the frequency of infection of birds reaches 25-40% in pigeons, 45-83% in rooks and 90% in ravens. Natural reservoirs of the pathogen are often pigs, cattle, chickens. Chickens, cattle, pigs and sheep, especially asymptomatic bacteria carriers, pose the greatest epidemiological hazard. Animals and birds – carriers emit pathogens into the environment for a long period (several months or even years). The role of sick people and bacteria carriers is less significant. The duration of the release of campylobacter in humans is 2-3 weeks, in rare cases it can reach 3 months.
The transmission mechanism is fecal-oral, the main mode of transmission is food (through meat and dairy products, vegetables, fruits), which is associated with the majority of group diseases and major outbreaks. Most often, the food transmission path is realized by eating insufficiently well thermally processed broiler chickens, as well as pork and its products (cutlets, jellies, etc.). The role of raw milk in the transmission of the pathogen is negligible. Possible household transmission path of the pathogen, especially when infected with newborns, pregnant women and the elderly. The disease can occur by direct contact with sick animals in the process of caring for them during calving and lambing. Infection occurs also when eating insufficiently heat-treated meat, infected in vivo or during cutting. Most outbreaks of campylobacteriosis in the United States are associated with the use of pasteurized milk. Of undoubted importance is the water way of transmission. Different types of bacteria are often isolated from the water of various reservoirs. Infected or sick women can transmit campylobacter to the fetus transplacentally, at birth or in the postnatal period. Cases of development of campylobacteriosis after blood transfusion, hemodialysis are described. Among animals, campylobacteriosis is transmitted by sexual, nutritional and contact pathways.
The natural susceptibility of people is high, as evidenced by the high level of campylobacteriosis in children under 2 years of age. The clinical picture of the disease can vary from asymptomatic carriage to severe lesions, which largely determines the state of resistance of the macroorganism and, above all, the immune status. Persons with immunodeficiencies are at risk. Maternal antibodies do not inhibit colonization by the bacteria of the intestines of newborns. The nature and duration of post-infectious immunity in campylobacteriosis is not well understood. Obviously, it is type-specific.
Major epidemiological signs. The disease is widespread. The spread of campylobacteriosis is caused by the intensification of animal husbandry, the increased international and national trade in animals, feed and animal products. Campylobacteriosis makes up from 5 to 14% of all registered cases of intestinal infections.
The incidence is sporadic; most often registered family lesions of campylobacteriosis. The characteristics of the epidemic and epizootic processes in campylobacteriosis are an increase in the circulation of pathogens among chickens and the related increase in the importance of poultry as a source of infection for people. In economically developed countries, infection is associated mainly with infected chicken meat, in developing countries – with water. The disease is registered throughout the year, with an increase in the incidence in the summer-autumn months. Campylobacter often causes “travelers’ diarrhea.” Important social factors affecting the prevalence of campylobacteriosis are sanitary and hygienic living conditions, national habits and nutritional patterns of the population. Campylobacteriosis affects people of all ages, but most often children from 1 to 7 years old. Increases the risk of infants becoming infected with an early transition to bottle-feeding. Nosocomial cases of campylobacteriosis are described among newborns.
Pathogenesis during Campylobacteriosis
The pathogenesis is still not fully understood. After entering the intestine, bacteria colonize the epithelium of the mucous membrane of the small and large intestine, provoking the development of an inflammatory reaction at the site of introduction. Inflammation is catarrhal or catarrhal-hemorrhagic in nature with infiltration of the mucous membrane by plasma cells, lymphocytes and eosinophils. Eosinophilic infiltration reflects the manifestations of the allergic component in the pathogenesis of the disease. Adhesion prevents mucus secreted by crypt cells and secretory IgA. The severity and duration of the course of the disease depends on the severity of adhesive processes in the future.
Following this, Campylobacter enters the intestinal epithelium cells, where they can stay for about a week, increasing their virulence. Toxic properties of pathogens determine bacterial enterotoxin and cytotoxin. The mechanism of enterotoxin activity is similar to that of cholera exotoxin (choleragen). The prevailing effect of enterotoxin gives the clinical picture of the disease common features with foodborne toxicoinfections. The active production of cytotoxin largely determines the development of the disease by the type of acute dysentery.
It is possible to generalize the process with hematogenous dissemination of the pathogen to various organs and tissues with the development of secondary septic foci in the form of multiple microabscesses in the central nervous system, pia mater, lungs, liver and other organs. Transplacental penetration of campylobacter in pregnant women leads to abortions, premature birth, intrauterine infection of the fetus.
In immunodeficient states, the development of the disease may follow the path of chroniosepsis with damage to the endocardium, joints and other organs.
Symptoms of Campylobacteriosis
Gastrointestinal form. The incubation period lasts an average of 2-5 days. Approximately half of the patients in the first 2-3 days of the disease appear non-specific flu-like symptoms: an increase in body temperature up to 38 ° C or more, chills, headache, pain in muscles and joints. Soon, features appear in the clinical picture of the disease, giving it the character of gastritis, gastroenteritis, gastroenterocolitis, enterocolitis, or colitis.
In accordance with the course variant, the clinical picture of the disease can be very similar to gastritic or gastroenteric variants of food toxicoinfection or acute dysentery. In such cases, the final diagnosis is made only after confirmation by bacteriological examination.
The development of enterocolitis and colitis is especially characteristic of patients in Europe and, in particular, in Ukraine. On the background of general toxic signs or somewhat later, abdominal pain occurs, localized mainly in the left iliac region or bearing a diffuse colicky character. The intensity is different; sometimes the pain is so pronounced that they simulate a picture of an acute abdomen. Nausea and vomiting are possible. The chair is abundant, liquid, fecal, offensive, green. The frequency of bowel movements varies from several times to 10 times a day or more. However, with the development of the colitis variant, the diseases of the feces quickly become scarce, mucus and blood streaks appear in them, and in about half of the patients the feces take the form of “rectal spittle”. Phenomena of hemocolitis are more characteristic of campylobacteriosis caused by C. jejuni. Tenesmus and false urges occur infrequently.
In rare cases, terminal ileitis and mesadenitis develop. 1-3 weeks after the onset of diarrhea, reactive arthritis may occur or spotted, spotty-papular or urticar exanthema may develop. The disease duration varies from several days to 2 weeks or more, relapses are possible.
Generalized form. The main causative agent – C. fetus subspecies fetus. Most often manifested by bacteremia, prolonged fever, but without multiorgan dissemination of pathogens and development in the organs of microabscesses. Pregnancy and young children are the most susceptible to this type of infection.
The clinical picture of septicopyemia often develops against the background of previous diseases – cirrhosis of the liver, diabetes mellitus, tuberculosis, malignant tumors, leukemia, etc., as well as in immunosuppressive conditions. Secondary septic foci can form in the lungs, liver, brain, kidneys, myocardium, peritoneum, forming against the background of severe intoxication manifestations of the corresponding clinical options – meningitis and meningoencephalitis, myocarditis and endocarditis, hepatitis, nephritis in general severe condition of patients. In these cases, the disease may complicate the development of infectious-toxic shock.
Chronic form. By the nature of development it resembles chroniosepsis; manifested sluggish course, subfebrile condition, progressive weight loss. Occasionally, patients develop abdominal pain, nausea, vomiting, and loose stools. Arthritis, keratitis, conjunctivitis, vaginitis, and vulvovaginitis may accompany the disease.
Subclinical form (bacteriocarrier). Characteristic selection of the pathogen with feces in the absence of clinical signs of disease, but with an increase in the titers of specific antibodies in the blood. The duration of the bacteria in most cases does not exceed 1 month.
In severe generalized infections, complications are associated with the formation of abscesses in various organs and the possible development of an infectious-toxic shock.
Diagnosis of Campylobacteriosis
The basis of the detection of bacteria in the stool, blood and other biological fluids. To isolate campylobacter, selective nutrient media are used to suppress the growth of the concomitant bacterial flora. Specific antibodies are also determined in the RSK, RPGA, ELISA, RCA and immunofluorescence methods, however, the timing of a significant increase in antibody titers (2nd week) reduces the diagnostic value of serological methods.
Gastrointestinal form of campylobacteriosis should be distinguished from other acute intestinal infections (which is clinically extremely difficult), as well as from surgical diseases of the abdominal organs. In some cases, the formation of suspicion of campylobacteriosis is aided by the appearance of signs of reactive arthritis or exanthema 1-3 weeks after the onset of diarrhea. The generalized form must be differentiated from septic conditions of various etiologies, meningitis, pneumonia. The chronic form of the disease requires a differential diagnosis with brucellosis, yersiniosis, toxoplasmosis.
Due to the difficulty of clinical differential diagnosis, the final diagnosis of campylobacteriosis is made only after confirmation by bacteriological examination.
Treatment in the development of the gastrointestinal form of the disease by type of gastroenteritis or enteritis is usually limited to the appointment of symptomatic agents; the need for etiotropic therapy is relative, since in such cases the disease is prone to self-restraint. Etiotropic treatment is prescribed for the colitis variant of the gastrointestinal form, generalized and chronic forms of campylobacteriosis, as well as in all cases in patients with a burdened premorbid background. Etiotropic therapy includes the administration of erythromycin, 500 mg 4 times a day (for children, 40 mg / kg / day). The reserve drugs are fluoroquinolones (ciprofloxacin), the second-line drugs are clindamycin, gentamicin, doxycycline, and furazolidone (in the case of the coltic variant). The doses of these drugs depend on the age of the patients, the course of treatment is at least 7 days. In some cases, repeated courses of etiotropic drugs or a change of drugs with their low clinical efficacy are required, which may be due to the increasing resistance of campylobacter to antibiotics, in particular to erythromycin.
Prevention of Campylobacteriosis
Epidemiological surveillance is aimed at identifying human diseases, continuous collection and analysis of data on infection cases and pathogens, as well as the dissemination of generalized information to optimize the system of preventive and anti-epidemic measures. Considering that the leading role among the sources of infection belongs to birds and animals, it is necessary to closely coordinate the work of medical and veterinary services in organizing epidemiological and epizootological supervision.
The basis of prevention consists of veterinary and sanitary measures aimed at preventing the infection of animals and birds, conducting destructive and therapeutic measures among sick animals. Prevention of the spread of the disease begins with monitoring the quality of feed, compliance with the rules of keeping animals and birds in farms and farms. The next stage is a veterinary-sanitary examination at slaughterhouses and compliance with sanitary-hygienic requirements for the technology of preparation and storage of dairy products, animal meat and poultry. For the specific prevention of campylobacteriosis in animals, various vaccines are used. The means of specific prophylaxis for people are absent. Conduct general sanitary-anti-epidemic measures, similar to those in other intestinal infections. In order to prevent nosocomial campylobacteriosis, a bacteriological examination of all patients admitted to infectious hospitals with acute intestinal diseases, regardless of the diagnosis, should be carried out in all somatic hospitals when symptoms of intestinal dysfunction are detected.
Activities in the epidemic focus
Similar to those with salmonellosis. Employees of food enterprises and persons equated to them who have undergone intestinal campylobacteriosis are subject to follow-up at 1 month after discharge from the hospital with a double bacteriological examination at the end of the observation period. Young children (up to 2 years) are under observation for 1 month with daily examination of the chair. If a recurrence of the disease is suspected, a repeated laboratory examination is prescribed.