What is Enterobacter aerogenes?
is a normal flora in the human intestine, belonging to the family of Enterobacteriaceae. It occasionally causes diseases when the human immune function decreases. The bacteria of Enterobacter aerogenes are rod-shaped, approximately 0.6-1.0 μm wide and 1.2-3.0 μm long, with a small capsule and no spores. They have peritrichous flagella and are motile. Additionally, Enterobacter aerogenes is Gram-negative and facultatively anaerobic. It can survive within a temperature range of 15-40℃, with an optimal growth temperature of 30℃ and a preferred pH environment of pH 7. When inoculated on general media such as TSA and incubated at 35℃ for 24 hours, Enterobacter aerogenes forms colonies with a creamy yellow and slightly transparent appearance. On EMB media, it forms colonies with a special red mucoid morphology, which can be used as a distinguishing feature to identify it from other enterobacteria.
1. The patient presents with respiratory symptoms such as fever and cough. During physical examination, a wet sound can be heard in the lungs. Imaging studies such as X-ray examination may show increased lung markings or infiltrative inflammatory lesions. In sputum culture, the percentage of Enterobacter aerogenes in the normal flora on the culture dish should be no less than 60%.
2. Etiological diagnosis: (1) Enterobacter aerogenes is isolated from sputum cultures on two consecutive occasions. (2) Quantitative sputum bacterial culture isolation: Enterobacter aerogenes is isolated, and the bacterial count is not less than 106 cfu/ml. (3) Enterobacter aerogenes is isolated from the pleural fluid or blood culture of patients with concurrent pleural effusion. (4) The number of Enterobacter aerogenes in lower respiratory secretions collected by artificial airway aspiration or bronchoscopy is not less than 106 cfu/ml. (5) The number of Enterobacter aerogenes isolated by BAL is not less than 104 cfu/ml. (6) Enterobacter aerogenes is isolated from lower respiratory secretions collected by bronchoalveolar lavage with contamination prevention and brush sampling with contamination prevention, and the number of Enterobacter aerogenes in patients with COPD, including bronchiectasis, is not less than 103 cfu/ml.
