Pneumonia caused by pseudomonas bacillus.

Pseudomonas aeruginosa is an opportunistic pathogen that is one of the most common causative agents of hospital pneumonia. Most often, this pneumonia develops in patients with burns, purulent wounds, urinary tract infections, in the postoperative period, in patients who have undergone major heart and lung surgery.

Pseudomonas aeruginosa produces a number of biologically active substances: pigments, enzymes, toxins. It secretes into the culture a characteristic blue-green pigment, pyocyanin, due to which the bacterium got its name.

The most important pathogenic factors of Pseudomonas aeruginosa are exotoxin A, hemolysin, leukocidin, etc. It also produces a number of enzymes - elastase, metalloprotease, collagenase, lecithinase.

The antigenic structure of Pseudomonas aeruginosa is represented by somatic (O-antigens) and flagellar (H-antigens) antigens.

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Symptoms of Pseudomonas pneumonia

It is generally accepted that the symptoms of pneumonia caused by Pseudomonas aeruginosa correspond to a severe course of bacterial pneumonia of another etiology.

Pneumonia begins acutely. The condition of patients quickly becomes severe. Patients have high body temperature (characterized by morning fever peaks), severe symptoms of intoxication, dyspnea, cyanosis, tachycardia.

Physical examination of the lungs reveals focal dullness of percussion sound, crepitation and fine bubbling rales in the corresponding area. A characteristic feature of pneumonia is the rapid appearance of new inflammatory foci, as well as frequent abscess formation and early development of pleurisy (fibrinous or exudative).

X-ray examination reveals focal darkening (foci of inflammatory infiltration), often multiple (characterized by a tendency to dissemination); in the case of abscess formation, cavities with a horizontal level are visible; intense homogeneous darkening with an upper oblique level is detected (with the development of exudative pleurisy).

Pneumonias caused by other gram-negative bacteria

Gram-negative bacteria of the Enterobacteriae family (E. coli, Enterobacteraerogenes, Serratia) are widespread in the external environment and are also representatives of normal human microflora. In recent years, these microorganisms have become etiologic factors of hospital-acquired pneumonia, especially aspiration pneumonia.

Pneumonia caused by these pathogens is more often observed in people who have undergone surgery on the urinary system, intestines; in patients who are severely weakened, exhausted, or suffering from neutropenia.

The clinical course of these pneumonias generally corresponds to the clinical course of other bacterial pneumonias, but is characterized by greater severity and higher mortality. For etiologic diagnostics, bacterioscopy of Gram-stained sputum is used - a large number of small non-negative rods are determined. To identify certain strains, sputum is sown on culture media. Enterobacter aerogenes is characterized by the ability to utilize nitrates and give a positive reaction with methyl red, while Serratia is characterized by the formation of a red pigment. Enzyme identification methods are also used using special polytropic media and identification systems. In recent years, monoclonal antibodies to E. coli antigens have been used to detect coli infection (using the immunofluorescence or enzyme immunoassay).

Diagnostic criteria for pneumonia caused by Pseudomonas aeruginosa

Diagnosis of pneumonia caused by Pseudomonas aeruginosa is based on the following principles:

• analysis of the clinical picture described above, severe pneumonia, early onset of pleurisy and abscess formation;
• the patient has burns, especially extensive and suppurating ones, purulent wounds, infectious and inflammatory diseases of the urinary tract;
• detection of gram-negative rods in sputum preparations stained with Gram. Pseudomonas aeruginosa has the appearance of straight or slightly curved rods with rounded ends;
• seeding of Pseudomonas aeruginosa from sputum, pleural cavity contents, wound discharge; Pseudomonas aeruginosa grows well on regular agar. In the case of association of Pseudomonas aeruginosa with bacteria of the genus Proteus, other enterobacteria, selective factors cetrimide and nalidixic acid are added to the medium. Serotyping of Pseudomonas aeruginosa is carried out using monospecific diagnostic sera;
• high titers of antibodies to Pseudomonas aeruginosa in the patient's blood (up to 1:12800 - 1:25000). Antibodies are determined using the indirect hemagglutination reaction. In healthy carriers of Pseudomonas aeruginosa, titers do not exceed 1:40 - 1:160;
• high titers of antibodies to Pseudomonas aeruginosa exotoxin A in the blood of patients (1:80 - 1:2,500). To determine them, the method of I. A. Alexandrova and A. F. Moroz (1987) is used with a special erythrocyte diagnosticum. The method is highly specific and highly sensitive. Antibodies to exotoxin A are absent in the serum of healthy people.

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Treatment of Pneumonia Caused by Pseudomonas Aeruginosa

The first-line drugs are penicillins of the fifth and sixth generations: azlocillin and pitracillin (up to 24 g per day), amdinocillin (40-60 mg/kg per day). In some cases, carbenicillin is very effective.

Of the cephalosporins, ceftazidime and cefsulodin (up to 6 g per day) are effective. It is advisable to combine these drugs with aminoglycosides.

Intravenous administration of ciprofloxacin (0.4-0.6 g per day), oral administration of other quinolones, parenteral administration of aztreonam (8 g per day) are highly effective. Aminoglycosides (amikacin, netilmicin) in maximum doses have not lost their significance. Combined use of penicillins with aminoglycosides or quinolones is possible.

Treatment of pneumonia caused by E. coli and Proteus

Most strains are sensitive to carbepicillin and ampicillin in high doses. The combination of ampicillin with the β-lactamase inhibitor sulbactam (unazin) is especially effective. These microorganisms are also highly sensitive to second- and third-generation cephalosporins.

The use of aztreonam and quinolones, chloramphenicol parenterally in high doses is also of clinical significance.

Reserve drugs include aminoglycosides, especially semi-synthetic ones (amikacin, netilmicin). Parenteral administration of bactrim is possible; intravenous metronidazole is successfully used (initial dose - 15 mg/kg, then 7.5 mg/kg every 6-8 hours).

Treatment of pneumonia caused by Serratia and Enterobacter

The best effect is provided by second- and third-generation cephalosporins (for example, cefotaxime 4-6 g per day intravenously or intramuscularly) in combination with carboxypenicillins. Alternative drugs are aztreonam, quinolones and aminoglycosides (in high doses). Most strains of this microorganism are also sensitive to chloramphenicol (in a dose of up to 3 g per day).

• Pneumonia - Treatment regimen and nutrition
• Antibacterial drugs for the treatment of pneumonia
• Pathogenetic treatment of pneumonia
• Symptomatic treatment of pneumonia
• Combating complications of acute pneumonia
• Physiotherapy, exercise therapy, breathing exercises for pneumonia
• Sanatorium and resort treatment and rehabilitation for pneumonia