Melodos

Melodos (from the Greek. melis SAP and eidos - view; synonym: false SAP, the disease Fletcher, disease Stanton, pneumoenteritis) - a relatively rare infectious disease (zoonoses)occurring in acute or chronic form with a large variety of symptoms, predominantly septico necrotic character. For a long time believed that melodos endemic only for South-East Asia, but in recent cases of this disease were registered in Indonesia, Australia, USA and the Philippines. From animal pathogen also highlighted in Madagascar.
Etiology. The causative agent of melioidosis is microorganism Malleomyces pseudomallei. By morphological, tinctorial and cultural characteristics, as well as on antigenic structure Malleomyces pseudomallei close to the pathogen Sapa, contains somatic, capsule and mucous antigens. The causative agent of melioidosis - stick with rounded ends 2-6x0,5-1 MK. True capsules microorganism has not, does not form spores. Unlike sticks Sapa has flagellar system. Young forms have one flagellum, more adult - multiple flagella, which are located beam on one of the poles. The causative agent is well painted aniline paints. In biological materials are often dyed bipolar. A gram is painted in the negative.
Wand melioidosis - optional gone anaerobic. Easily cultivated on conventional, as well as on synthetic protein-free environments.
Optimum temperature 37 C; pH of 7.5. If seeding in the broth is first formed on the surface smooth, thin, grayish color film, it sinks to the bottom, forming a thick sticky residue. Colony on agar plates differ polymorphism. For the S-form is characterized by smooth convex transparent colony mucous consistency of the correct form with smooth edges with a diameter of 1-2 mm Microbes in the R-form form opaque colony jagged and dry wrinkled surface. Characteristic yellow-brown color appears on 4-7 day growth. R-form is most virulent. On potato slices in less than a day appears transparent coating which then becomes white, opaque. Over time, the plaque becomes brown in color.
Enzymatic activity sticks melioidosis varies from a wide range degradable carbohydrates (produces acid without gas) to total loss of the subcultures in saharomiceta properties. Milk wand melioidosis peptonize; indole does not form; restores nitrates into nitrites; has the catalase activity. Proteolytic properties are weak.
Wand melioidosis in the environment is able to maintain activity in tropical temperatures: in the faeces and soil - within 25-30 days, in the dead - to 20 days in water up to 40 days. In the water standing water is the reproduction of the organism. Sensitivity to disinfectants pathogen M is not different from most other vegetative forms of microorganisms. Phenol and as Lysol disinfectant ineffective. The pathogen is highly sensitive to heat - at temperature of 56 degrees microbial suspension inactivated in several minutes.
Epidemiology. The causative agent of melioidosis pathogenic for a wide range of laboratory and farm animals. To him the most sensitive at any way of getting infected Guinea pigs and hamsters, to a lesser extent white mice and rabbits. In nature, the pathogen isolated from rats, cats, dogs, horses, cows, pigs, sheep, goats, have sporadic cases and epidemic. The potential importance of large animals as tank infectious agent and discovered in recent years, the presence sticks melioidosis in stagnant ponds changed existed earlier views on the epidemiology of melioidosis. For a long time the natural reservoir of infection is considered as a wild rat, and infecting people were seen as the result of the consumption of food and water contaminated by secretions of these animals. However, epidemiologic study of rats in disadvantaged by M. districts not confirmed this concept. The accumulated facts suggest that the most likely reservoir of infection are a pet that can contaminate water and soil discharge ulcers, urine, and sputum. It is also possible that Malleomyces pseudomallei can exist in nature as a saprophyte.
In the human body parasites can penetrate the gastrointestinal tract, damaged skin, mucous membranes of the nose and conjunctiva. A certain role in the dissemination of melioidosis, apparently, can play some blood-sucking insects (mosquitoes, fleas). From person to person M not passed.
Pathogenesis and pathological anatomy. The pathogenesis of melioidosis studied enough. After overcoming the initial barriers, the activator is distributed throughout the body and causes numerous destruction of internal organs, autopsy which are based necrotic changes (cheesy or coagulation), and hemorrhage. Along with septicemia, apparently, an important role in the pathogenesis of the disease plays and toxemia. At the opening died from acute forms of melioidosis marked characteristic generalized destruction as cheesy knots, representing an accumulation of pus cells, surrounded by a zone of hyperemia. The merger of these formations gives cheesy-purulent foci and abscesses, which are especially characteristic of subacute forms. Lesions are observed in the lungs, liver, spleen, kidneys, urinary bladder, lymph nodes, subcutaneous adipose tissue and muscles. Erosivno-azwenne changes may be in the intestine. In chronic cases also affects the bones. There were indications that melodos a person can take place in a latent form, and the disease is activated when surgery and occurrence of other diseases.
The clinical picture and over. There are three forms of melioidosis: septic, septikopiemicheskih and local.
Septic form is characterized by the fact that the pathogen is in the blood, but the disease is fast, the patient dies faster than time to develop purulent lesion. To use as a therapeutic agent chloramphenicol legality in this form reached 100% (currently 50%). At extremely acute death can occur within hours after the onset of the disease, usually it occurs in 2-5 days. The disease begins rapidly - with chills, vomiting, symptoms sharp dehydration. The temperature will rapidly reach high figures (40-41 degrees) and maintained at this level until the terminal period. Patients complain of severe headache. Quickly comes unconsciousness, appears nonsense. From the side of cardiovascular system are marked expressed tachycardia, arrhythmia. Appear shortness of breath and cough accompanied by Department bloody sputum. Auscultatory sometimes already in the first days of the disease in the lower lung tapped dry and moist rales. Often appears very various skin rashes (roseolous, crepadona, skarlatinopodobnoy, hemorrhagic vesicles, pustules). In children, as a rule, there is a violation of the activity of the intestines. In adults, it happens rarely. In some cases, there is jaundice. Enlarged liver and spleen is not mandatory symptom. In the study of blood find pronounced neutrophilic leucocytosis. The differential diagnosis should be carried out with cholera (see), septic or pneumonic form of plague (see), typhoid fever (see), typhus (see), malaria (see), sometimes natural smallpox (see).
Septikopiemicheskoy form, occurring most frequently, can be developed either independently or from septic form, if the patient dies within the first 10 days of the disease. This form is characterized along with bacteremia purulent metastases in the internal organs. Septikopiemicheskoy form can be acute, subacute and chronic. Beginning of the disease is always sharp, forecast serious. Mortality even when modern methods of treatment is about 30% . General condition of the patient serious. The temperature is kept at the level of 40 degrees, sometimes giving remission. Symptoms varies considerably and depends on the location of the lesions. Most often affects the lungs, in the tissue of which appear seals exposed subsequently decay caving. Describes the clinical forms associated with kidney, liver, bladder, serous membranes, which can exist independently or combined with process in the lungs. In patients with this form of melioidosis describes various skin rashes, jaundice, sometimes gastrointestinal disorders. Purulent foci in the bones, muscles and lymph system usually only find at showdown. Differential diagnosis difficult. Pulmonary lesions when melioidosis more likely to be diagnosed as acute tuberculosis. The diagnosis of tuberculosis is rejected in the absence in the sputum of Mycobacterium tuberculosis. Other containment defeats the differential diagnosis have to spend with dysentery abscesses of the liver, typhoid fever, complicated suppurations and septicopyemia caused by other pathogens. When expressed lesions in lymph nodes may sometimes be necessary to exclude bubonic plague.


The local form of melioidosis characterized by the formation of a single abscesses of different localization, not accompanied by a pronounced symptoms of total infections (as opposed septikopiemicheskoy the form in which local lesions occur on the background of infectious process). Abscesses may appear on the surface of the skin, deep tissue, muscles and lymph nodes.
Often in the process involved and bones. Entrance gate of infection in the local form most often traumatic injuries. The severity of the disease varies. Usually a moderate temperature response: sometimes fever nonexistent. At a superficial lesions of the disease easy, but with extensive dissemination process and long for the development of cachexia fatal. In some cases, the local form can assume in septikopiemicheskoy. The differential diagnosis should be carried out with fungal, syphilis, tuberculosis lesions and staphylococcal infection.
Diagnosis of melioidosis reliably established only on the basis of laboratory tests, consisting primarily in the selection and identification of the pathogen. Material for research are the blood, sputum and purulent discharge. Blood cultures (10 ml) produced by open-hearth broth in flasks (250 ml) and incubated at temperature 37A 24 hours. At the same time, it is recommended infection male Guinea pigs. In positive cases, developing orchitis, and the animal dies. The deal reveals the characteristic pathological changes. The sputum and pus is done on a regular or elective nutritionally dense environment (Wednesday Levin with lactic acid ammonium and 2-, 3-, 5-triphenyltetrazolium). The selection of colonies should use oxidase breakdown. Identification allocated microbe is usually easy. For serodiagnosis used agglutination reaction, and haemagglutination of complement fixation. None of them can differentiate melodos from Sapa. The most reliable results are obtained by the reaction of haemagglutination. The patient is recommended that all three reactions of paired sera, taken from a ten-day interval. Allergic diagnostics is under development. For the production of samples used white Maureen (a drug similar to mallein) or capsular antigen. Intradermal reaction is applicable only for the diagnosis of chronic forms.
Treatment. The most effective treatment of all forms of melioidosis is chloramphenicol. Treatment with high doses (3-4 grams per day). The course lasts for several weeks. The reduction in the dose and reduce the rate may cause a relapse. Mandatory intensive vitamin. In those cases, when the disease caused by strains, are not sensitive to this antibiotic is recommended combination levomitsetina and aureomycin or levomitsetina and terramycin. From sulfa drugs are most effective sulfadiazine in usual dosage. He gives good results in case of chronic forms and can be combined with chloramphenicol. When local forms resort to surgical intervention. In some cases a good effect gave autovaccinotherapy.
Prevention of melioidosis is to conduct from General hygienic measures in areas not favorable to this disease, the aim of which is to prevent the ingress of parasites in the body (thermal processing of food and water, timely processing of the Russian Academy of Sciences, the prohibition swim in stagnant ponds). Vaccinal prevention of melioidosis not developed. Patients, although Meters almost not contagiosum, it is recommended to place them in a separate chamber, because in some forms patients emit into the environment a large number of microbes. It should also be current disinfection of faeces, urine and used dressings.