PAEA Surgery End Of Rotation (EOR) Practice Exam

What is the most common cause of postoperative pneumonia or in patients within the ICU?

1. Gram-positive bacteria

2. Viral infections

3. Gram-negative bacteria

4. Fungal infections

The correct answer is: Gram-negative bacteria

Postoperative pneumonia in patients, particularly those in the ICU, is predominantly caused by gram-negative bacteria. This group includes organisms such as Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae, which are known to be more prevalent in the hospital environment, especially among individuals who have undergone surgical procedures. Patients in the ICU are often immunocompromised, subjected to invasive procedures, and may have prolonged mechanical ventilation, all of which heighten their risk for infections caused by these bacteria. Gram-negative bacteria are also associated with more severe and complex clinical scenarios, contributing to higher morbidity and mortality rates compared to other pathogens. While gram-positive bacteria, viral infections, and fungal infections play roles in respiratory infections, they do not account for the predominant cases of pneumonia post-surgery or in ICU settings as gram-negative bacteria do. Gram-positive bacteria may be more commonly associated with skin and soft tissue infections, and while viral and fungal infections can occur, they are less frequent as primary causes of pneumonia in these high-risk patient populations.