Overview of Proteus mirabilis
Aspergillus is a common species of normal intestinal flora, and the main ones associated with human infections are Aspergillus commonus and Aspergillus exoticus, which can cause urinary tract infections and postoperative abdominal incision infections, and rarely cause pneumonia. Similar to other gram-negative bacillus pneumonia, it is mainly inhalation of oropharyngeal colonization of Aspergillus. Normal people carry this bacterium rarely, the elderly, the use of antacids or H2 receptor blockers lead to increased pH of gastric juice, poor personal hygiene, gastrointestinal surgery, oropharyngeal colonization of Aspergillus spp. Increased, when the body’s resistance is reduced and the inhalation of the bacterium in larger quantities, more virulent, the pneumonia ensues. It is mostly a nosocomial acquired infection.
Etiology
The bacteria of the Enterobacteriaceae family are gram-negative, and the main ones related to human infection are Proteus vulgaris and Proteus mirabilis. The bacterium has obvious polymorphism, which can be spherical or filamentous, with circumferential flagella. It grows well on ordinary medium, and the phenomenon of migratory growth is an important identifying characteristic. Cultures have a special odor. Hemolysis can be seen in blood agar medium. Aspergillus can be found in soil, sewage and intestinal tract. Staff hands and instruments are common modes of transmission.
Symptoms
Aspergillus pneumonia occurs in elderly men with pre-existing chronic lung disease, intoxication, renal failure, and diabetes mellitus. Other susceptibility factors include the use of antibiotics, glucocorticoids and immunosuppressive agents, mechanical ventilation, and ICU admission. Common symptoms include cough, coughing up thick yellow sputum, chills, fever, chest pain, dyspnea, and neurological symptoms such as delirium and tremor in the limbs, which are rare in individual patients. Sometimes only mild to moderate systemic toxicity symptoms such as anorexia, fatigue, drowsiness, irritability, etc. are manifested.
Physical examination may reveal solid signs of lungs such as increased trembling, turbid tones on percussion, and audible tubular breath sounds. More than half of the patients have wet rales.
Examination
1. Laboratory examination
The total number of blood leukocytes is increased and the nucleus is left shifted. Sputum culture is the main basis for confirming the diagnosis of Aspergillus pneumonia.
2. Other auxiliary examinations
X-ray manifestations mostly show segmental solid lesions, with dense exudative shadows distributed along the lobes or segments of the lungs, preferably in the posterior segment of the upper lobe of the right lung and the dorsal segment of the lower lobe of the right lung. A few may show patchy bronchopneumonia.
Diagnosis
Mycobacterium avium pneumonia is most common in middle-aged and elderly males, and most often has a primary disease. Confirmation of the diagnosis depends on bacteriologic examination.
Differential diagnosis
The clinical and chest X-ray changes of Aspergillus pneumonia are similar to those of most enteric bacterial pneumonias (e.g., L. pneumophila, E. coli, etc.), and the differential diagnosis relies on the examination of sputum or other bronchial secretions for pathogenic bacteria.
Complications
Pleural effusion is rare. Lung abscess is more common. Complicated bacteremia is rare.
Treatment
1. General treatment
(1) Supportive therapy, including keeping the airway open, oxygen inhalation, adequate nutrition and fluids to keep the body in a safe and stable state.
(2) Positive treatment of primary diseases The onset of S. transformans pneumonia is usually associated with underlying diseases such as chronic lung disease, diabetes, alcoholism and renal disease, etc. Positive treatment of these primary diseases is conducive to the improvement of the patient’s physical condition and the increase of resistance.
2. Anti-infection treatment
The application of antibacterial drugs is the key to the treatment of Aspergillus pneumonia. However, since many strains of bacteria, such as common Aspergillus, bizarre Aspergillus, etc., have natural drug resistance, so on the basis of empirical treatment, we must refer to the results of in vitro drug sensitivity test.
(1) Third-generation cephalosporins Before the results of in vitro bacteriologic and drug susceptibility tests are available, third-generation cephalosporins targeting Gram-negative bacilli are currently advocated for Gram-negative bacilli, especially for nosocomial-acquired pneumonia, or in combination with aminoglycoside antibiotics. Commonly used drugs ceftriaxone (cefotriazine).
(2) Aminoglycosides are often preferred to bacteria other than Streptococcus pyogenes, the most commonly used for amikacin, but for those with renal insufficiency or the elderly should pay attention to the toxic side effects, if necessary, can be used for the blood concentration test, can be used in conjunction with the third-generation cephalosporins.
(3) Quinolones Quinolone antibiotics can be used when the response to cephalosporins and aminoglycoside antibiotics is poor, such as ciprofloxacin, ofloxacin, levofloxacin, sparfloxacin (sparfloxacin) and so on for intravenous application.
When the pathogenetic results are obtained, antibiotics should be adjusted according to the drug sensitivity results in a timely manner and sensitive antibiotics should be used.
Prognosis
The morbidity and mortality rate of Aspergillus pneumonia is 18% to 21% of its occurrence, which is mainly related to its poor morbidity base, persistence of germs, drug resistance and old age.
Prevention
1. Remove the source of contamination, strictly disinfect, observe the isolation system as well as actively treat the original disease.
2. Use selective intestinal decontamination method to remove gram-negative bacilli in the intestines.