Pneumonia caused by Pseudomonas aeruginosa

Pseudomonas aeruginosa (Pseudomonas aeruginosa) is a conditionally pathogenic microorganism, which is one of the frequent pathogens of hospital pneumonia. Most often, this pneumonia develops in patients with burns, purulent wounds, urinary tract infections, in the postoperative period, in patients who underwent severe heart and lung operations.

Pseudomonas aeruginosa produces a number of biologically active substances: pigments, enzymes, toxins. She singles out into the culture a characteristic blue-green pigment piocyanin, thanks 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 the Pseudomonas aeruginosa is represented by somatic antigens (O-antigens) and flagellates (H-antigens).

[1], [2], [3], [4], [5], [6], [7],

Symptoms of pneumonia caused by Pseudomonas aeruginosa

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

Pneumonia begins acutely. The condition of the patients quickly becomes severe. Patients have a high body temperature (typical morning fever peaks), symptoms of intoxication, dyspnea, cyanosis, and tachycardia are sharply expressed.

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

Radiographic examination reveals focal dimming (foci of inflammatory infiltration), often multiple (characterized by a tendency to disseminate), with abscessing visible cavities with a horizontal level, an intense homogeneous darkening with an upper oblique level (with the development of exudative pleurisy).

Pneumonia caused by other Gram-negative bacteria

Gram-negative bacteria of the Enterobacteriae family (E. Coli - Escherichia coli, Enterobacteria erogenes, Serratia) are widely distributed in the environment and are also representatives of normal human microflora. In recent years these microorganisms have become etiological factors of intra-hospital pneumonia, especially aspiration.

Pneumonia caused by these pathogens is more often observed in persons who underwent surgery on the organs of the urinary system, the intestines; in patients severely debilitated, depleted, suffering from neutropenia.

The clinical course of these pneumonia in general corresponds to the clinic of other bacterial pneumonia, but is characterized by greater severity and higher lethality. For etiologic diagnosis, a bacterioscopy of Gram-stained sputum is used - a large number of small non-negative rods are detected. For the identification of certain strains, sputum culture is carried out on culture media. For Enterobacter aerogenes is characterized by the ability to utilize nitrates and give a positive reaction with methyl red, Serratia is characterized by the formation of a red pigment. Enzyme identification methods using special polytropic media and identification systems are also used. In recent years, monoclonal antibodies to E. Coli antigens have been used to detect coli infection (using the immunofluorescence or immunoassay method).

Diagnostic criteria of Pseudomonas aeruginosa pneumonia

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

• analysis of the clinical picture described above, severe pneumonia, early pleurisy and abscessing;
• presence of burns in the patient, especially extensive and suppurative, purulent wounds, infectious and inflammatory diseases of the urinary tract;
• Detection in preparations of sputum with Gram staining of gram-negative rods. Pseudomonas aeruginosa has the appearance of straight or slightly curved sticks with rounded ends;
• sowing of Pseudomonas aeruginosa from sputum, contents of pleural cavity, separable wounds; Pseudomonas aeruginosa grows well on ordinary agar. In the case of the association of Pseudomonas aeruginosa with bacteria of the genus Proteus, selective factors of cetrimide and nalidixic acid are added to other media by other enterobacteria. Serotyping of Pseudomonas aeruginosa is carried out using monospecific diagnostic sera;
• high titres of antibodies to Pseudomonas aeruginosa in the patient's blood (up to 1: 12800 - 1: 25000). Antibodies are determined by the indirect hemagglutination reaction. In healthy carriers of Pseudomonas aeruginosa, the titers do not exceed 1:40 - 1: 160;
• high titers of antibodies to exotoxin A of Pseudomonas aeruginosa in the blood of patients (1:80 - 1: 2,500). To determine them, the method of IA Aleksandrova and AF Moroz (1987) is applied using a special erythrocyte diagnosticum. The method is highly specific and highly sensitive. In the serum of healthy people antibodies to exotoxin A are absent.

[8], [9], [10], [11], [12]

Treatment of pneumonia caused by Pseudomonas aeruginosa

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

Of cephalosporins, ceftazidime and cefzulodin are effective (up to 6 g per day). These drugs should be combined 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. Do not lose their value and aminoglycosides (amikatsin, netilmitsin) in maximum doses. A combined use of penicillins with aminoglycosides or quinolones is possible.

Treatment of pneumonia caused by Escherichia coli and proteus

Most strains are sensitive to carbepicillin and ampicillin in high doses. Especially effective is the combination of ampicillin with the β-lactamase inhibitor sulbactam (unazine). These microorganisms possess high sensitivity to cephalosporins of the second and third generations.

Clinical importance is also the use of aztreonama and quinolones, chloramphenicol parenterally in large doses.

Aminoglycosides, especially semisynthetic (amikacin, netilmicin) can be classified as reserve drugs. Parenteral administration of bactrim is possible, metronidazole is administered intravenously (initial dose is 15 mg / kg, then 7.5 mg / kg every 6-8 hours).

Treatment of pneumonia caused by serration and enterobacter

The best effect is given by cephalosporins of the second and third generations (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 (at 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
• Fighting complications of acute pneumonia
• Physiotherapy, exercise therapy, respiratory gymnastics with pneumonia
• Sanatorium treatment and rehabilitation for pneumonia