Transmission routes of Acinetobacter baumannii

Acinetobacter baumannii is a pathogen with a wide distribution range and a very long survival period. After the human body is infected, the patient's treatment process is very complicated and has a great impact on high-risk patients. It has extremely strong resistance to drugs and can easily cause a variety of diseases, which has caused people to pay great attention to it. So what are the specific transmission routes of Acinetobacter baumannii?

In terms of the source of infection, there are both exogenous infections and endogenous infections. Aspiration of bacteria from the oropharynx is likely the primary pathogenesis of endogenous infection. Symptoms include fever, cough, chest pain, shortness of breath and bloody sputum. There may be fine moist rales in the lungs. Lung imaging often shows features of bronchopneumonia, and may also show lobar or lamellar infiltration shadows, and occasionally lung abscess and exudative pleurisy.

2. Wounds and skin infections

Surgical incisions, burns and traumatic wounds are prone to secondary Acinetobacter skin infection or mixed infection with other bacteria. The clinical features are not significantly different from those caused by other bacterial infections. Most of the time there is no fever. Occasionally, it may present as cellulitis.

Acinetobacter can cause pyelonephritis, cystitis, urethritis, vaginitis, etc. It can also present asymptomatic bacteriuria, but it cannot be distinguished clinically from infections caused by other bacteria. Its causes are mostly indwelling catheterization, cystostomy, etc.

4. Bacteremia

Bacteremia is the most serious clinical type of Acinetobacter infection, with a mortality rate of over 30%. Most of them are secondary to infection in other parts of the body or after intravenous catheterization. A few are primary after infusion, including infusion of antibiotics, corticosteroids, anti-tumor drugs, etc. There are fever, systemic poisoning symptoms, skin petechiae or ecchymoses, hepatosplenomegaly, etc. In severe cases, there is septic shock. A few can form multiple bacterial bacteremia with other bacteria.

Meningitis often occurs after cranial surgery. Symptoms of purulent meningitis include fever, headache, vomiting, neck stiffness, and positive Kernig's sign. Laboratory: The total white blood cell count is normal or increased, and the number of neutrophils is increased. Sputum specimens obtained by anti-contamination sampling technology have greater diagnostic value. The presence of Gram-negative cocci in sputum smears can be an important clue to diagnosis.

Bacterial species identification

The biochemical identification was mainly based on the API-20NE system, and 5 necessary tests were added. The results showed that the four species of Acinetobacter all met the general characteristics of the genus Acinetobacter: oxidase negative, catalase positive, non-motile, indole negative, non-fermentation of sugars, and non-reduction of nitrates. In the API-20NE system, the identification percentage (%id) of 72 strains of Acinetobacter baumannii was ≥99.0%; the %id of 15 strains of Acinetobacter calcoaceticus was ≥99.0%; the %id of 3 strains of Acinetobacter junii was between 95.0% and 99.9%, with an average of 98.3%; the %id of 6 strains of Acinetobacter loffield was between 97.0% and 99.9%, with an average of 99.4%.