Pseudomonas infection is an infectious disease caused by the invasion of Pseudomonas aeruginosa. It is the leading nosocomial infection. Chronic forms are characterized by damage to the respiratory tract with the formation of “biological films”, for acute course – bacteremia and damage to internal organs. Diagnosis is based on the detection of the pathogen in the biological materials of the patient. Treatment includes etiotropic antibacterial therapy, detoxification agents, antipyretics and other symptomatic drugs. In some cases, surgical treatment is indicated.
B96.5 Pseudomonas (aeruginosa) (mallei) (pseudomallei) as a cause of diseases classified in other categories
Pseudomonas infection was first described in 1850 by the French surgeon Sedile. In 1882, the French military pharmacist Jessard managed to isolate a pure culture of the pathogen, and in 1916 the epidemiology of this disease became known. The disease is widespread everywhere, bacteria are found in soil, water and plants. There is no clear seasonality. In hospitals, physiotherapy and resuscitation equipment is considered a favorite localization. Risk groups are premature newborns, children under 3 months, the elderly, patients of hemodialysis, chemotherapy, neurosurgery and intensive care units, patients with cystic fibrosis and immunosuppression.
The causative agent of the disease – Pseudomonas aeruginosa and its strains, is a conditionally pathogenic microorganism capable of causing damage only in the absence of an adequate response of the immune system. The source of infection is sick people and animals, bacterial carriers, the predominant localization of the microorganism – skin, intestines. Infection occurs by airborne droplets and food. The path of infection in hospital infection is more often contact – through non-sterile instruments, the hands of medical personnel and patient care items. The bacterium dies during boiling, during autoclaving, as well as when exposed to 3% hydrogen peroxide and chlorine-containing disinfectants.
When microbes get on damaged skin or mucous membrane, massive destruction of tissues occurs due to exposure to exotoxins and substances produced by bacteria. Normally, the mucous membrane of the body is able to neutralize the effects of Pseudomonas aeruginosa due to mucociliary clearance and mechanical barrier. The attraction of neutrophils and active phagocytosis enhance the formation of many antibacterial cytokines, enzymes and free radicals, serve as activators of the complement system and other links of humoral immunity.
From 33 to 83% of Pseudomonas aeruginosa strains have an evolutionarily determined mechanism of protection against the immune system – the formation of biofilms consisting of a cluster of affected cells and an extracellular matrix, including fibrin, secretory mucosal secretions, alginate, polysaccharides and lipids. It is known that bacteria lyse neutrophils, enhancing the growth of their own biofilms.
Lesions caused by Pseudomonas aeruginosa can be divided into local and generalized (septic). Some types, including infections of the central nervous system, heart and mediastinum develop due to the dissemination of the pathogen. Depending on the topology of the inflammatory focus, the following forms of pseudomonas infection are distinguished:
- Infection of the respiratory tract. Patients who are on long–term artificial lung ventilation suffer tracheobronchitis in 30% of cases and pneumonia of pseudomonas aeruginosa in 24% of cases.
- Infection of ENT organs. Sinusitis rarely develops, while up to 40% of chronic otitis media accounts for Pseudomonas aeruginosa.
- Gastrointestinal infection. It manifests itself in the form of severe diarrhea, often with a fatal outcome among children under one year old. About 16% of postoperative peritonitis is associated with the pathogen.
- Eye infection. It is associated with prolonged use of contaminated contact lenses and eye drops, often leads to panophthalmitis.
- Infection of the urinary system. The development of catheter-associated acute pyelonephritis is most likely. Up to 13% of cases of acute prostatitis are associated with this pathogen.
- Skin infection. Occurs after a stay in the pool with a reduced concentration of disinfectants, can affect nails, subcutaneous tissue, muscle fascia with the formation of necrosis.
- Wound infection. It accounts for up to 10% of all combat infectious complications, causes about 30% of purulent processes in burn disease. It is considered a supporting factor in the formation of trophic ulcers.
Pseudomonas aeruginosa symptoms
The incubation period of pathology is extremely variable, can range from several days to decades, since the microorganism is one of the conditionally pathogenic components of the human microflora. Clinical manifestations depend on the affected organ. In adults with invasion of the digestive tract, the first symptoms are fever (no more than 38.5 ° C), decreased appetite, chills, weakness, nausea, less often vomiting, bloating and abdominal pain, frequent mushy stools with blood and mucus.
Small children with gastrointestinal tract damage become sluggish, drowsy, refuse to eat and drink, regurgitate, gastroenterocolitis occurs with a high risk of intestinal bleeding. Pseudomonas aeruginosa pathology of ENT organs is manifested by fever of 37.5 ° C and above, sharp pain in the ear, hearing loss, yellow-green abundant discharge, sometimes with an admixture of blood. The defeat of the respiratory tract occurs in the form of pneumonia – with an increase in body temperature of more than 38 ° C, increasing shortness of breath, cough with copious mucopurulent sputum.
Pseudomonas infection of the urinary system is characterized by fever, lower back pain, frequent painful urination, a feeling of incomplete emptying of the bladder, a change in the color and smell of urine. Ocular symptoms of Pseudomonas aeruginosa invasion are more often detected in the area of one eyeball, begin with the appearance of pain, pain, burning sensation, foreign body, lacrimation, photophobia and mucopurulent copious discharge. In the future, there may be a decrease and blurred vision.
The skin lesion is manifested by rashes in the form of spots and pustular elements throughout the body, including a rash on the palms, soles and in the nasopharynx, an increase in lymph nodes, constant headaches (the so-called headache of swimmers), green coloring of one, less often two nail plates, the formation of painful seals in subcutaneous fat. Wound infection of the pathogen is accompanied by the appearance of blue-green purulent discharge and purulent-hemorrhagic crusts, an increase in the redness zone around the wound.
The multisystem and clinical diversity of the symptoms of pseudomonas infection is reflected in the number of complications of this condition. The most frequent negative consequences include generalization of the infectious process, infectious and toxic shock, necrotic colitis in infants. There is a high probability of abscess formation and gangrenous changes. The sluggish course of infection on the mucous membranes of the ear, oropharynx, nose, conjunctiva and lungs leads to the chronization of the inflammatory process, the formation of mesotimpanitis, bronchiectasis, creeping corneal ulcer, partial or complete deafness, unilateral blindness.
The diagnosis is made on the basis of data obtained during the consultation of an infectious disease specialist. In the event of extensive purulent lesions, a surgeon’s consultation is mandatory, other specialized specialists are invited according to the indications. The most common diagnostic methods for confirming the pseudomonas etiology of the disease are the following instrumental and laboratory studies:
- Physical examination. During an objective examination, pay attention to the color of the wound discharge, the presence of a rash. The lesion of the outer ear, eye is manifested by hyperemia, abundant mucopurulent discharge. In the lungs with pneumonia, a weakening of breathing is heard, with percussion – a dulling of sound. In the case of gastroenterocolitis, soreness along the course of the intestine, rumbling is detected; a visual assessment of bowel movements is mandatory.
- Laboratory tests. Blood test indicates the presence of leukocytosis, a rod-shaped shift to the left, acceleration of ESR. In biochemical parameters, there is an increase in ALT, AST, CRP, a decrease in total protein, and hypoalbuminemia. In the general analysis of urine, proteinuria, hematuria is possible. Sputum analysis confirms a large number of bacteria and leukocytes. In the cerebrospinal fluid in brain lesions, neutrophil pleocytosis, cell-protein dissociation is detected.
- Identification of infectious agents. The gold standard is a bacteriological study carried out in modern conditions by mass spectrometry with mandatory determination of the antibacterial sensitivity of the bacterium. Detection of the pathogen is possible with the help of PCR of biological material from the pathological focus. Serological diagnostics (ELISA) is performed repeatedly with an interval of at least 10-14 days to detect the growth of antibody titer.
- Instrumental techniques. Chest X-ray, less often MRI or CT is performed to verify lung lesions, differential diagnosis. Abdominal ultrasound, genitourinary system, soft tissues, bones and retroperitoneal space allows you to establish the primary focus of inflammation. EchoCG is indicated for suspected infectious endocarditis. Colonoscopy, EGD are prescribed in order to exclude neoplasms of the digestive tract.
Differential diagnosis of pseudomonas infection is difficult due to the variety of clinical forms of the disease. The most common lesions of the gastrointestinal system are differentiated with salmonellosis, shigellosis and pseudomembranous colitis. Skin manifestations are distinguished from purulent-necrotic lesions of streptococcal and staphylococcal etiology. Infections of the respiratory system may resemble caseous pneumonia in tuberculosis, sarcoidosis, bacterial pneumonia. The causes of sepsis can be various viruses, bacteria and fungi.
Pseudomonas aeruginosa treatment
Inpatient treatment is recommended for patients with organ lesions, moderate and severe course of the disease. Patients with nosocomial pseudomonas infection continue treatment in the department where they were before the manifestation of the infectious process, with mandatory implementation of all anti-epidemic measures and rehabilitation of equipment. Bed rest is necessary until a steady relief of fever for 3-5 days, its duration depends on the degree of invasion, the presence of complications and decompensation of concomitant diseases. A special diet has not been developed, a meal with a sufficient amount of protein, an adequate drinking regime is recommended.
Etiotropic therapy of pseudomonas infection is complicated by the presence in the microorganism of natural resistance to some antibiotics of the penicillin and tetracycline series, trimethoprim, partly to cephalosporins, carbapenems and aminoglycosides. The use of antibacterial agents is allowed in the mode of monotherapy or combined treatment with a combination of several groups of drugs prescribed locally and systemically. The main antibiotics used to inactivate pseudomonas infection are “protected” penicillins, fluoroquinolones, ceftazidime, cefepime, imipenem, polymyxin E, gentamicin, amikacin.
Hyperimmune anti-pseudomonasal donor plasma and anti-pseudomonasal gamma globulin are considered means of combating infection, These drugs are used less often due to the possible development of serum sickness, they are indicated for a sluggish inflammatory process. Symptomatic treatment includes detoxification therapy, anti-inflammatory and antipyretic agents. Surgical intervention is necessary for localized and diffuse purulent processes, consists in opening and drainage of ulcers, less often – amputation of a limb. Local application of a solution of hydrogen peroxide, ointments with antibiotics is allowed.
Prognosis and prevention
The prognosis is always serious. Pseudomonas Aeruginosa often makes polymicrobial associations – with candida, staphylococci, klebsiella, which makes the course of pathology heavier. Mortality in organ lesions is 18-61%, increases in the case of invasion of the nosocomial strain of Pseudomonas aeruginosa. Predictors of probable death are the ability of the pathogen to produce exotoxin U, multi-antibiotic resistance and septic shock.
Specific prophylaxis (polyvalent vaccine) is indicated for medical workers, burn patients, patients with open fractures and deep wounds, persons with immune deficiency, senile people. Non-specific measures are reduced to strict compliance with the rules of processing medical instruments and equipment, control of contamination with Pseudomonas aeruginosa of personnel. Restorative methods are important – hardening, normal sleep, proper food, walking, physical activity, strict observance of personal hygiene and timely sanitation of purulent foci.