This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
In the neutropenic patient, which of the following wound be most commonly encountered as a cause of bacterial meningitis and brain abscess? 
Select and explain. 
A. Pseudomonas aeruginosa, B. Staphylococcus aureus, C. Haemophilus influenzae, D. Bacteroides fragilis
A: Pseudomonas aeruginosa
Answer: A: Pseudomonas aeruginosa 
Explanation: The pneumococcus is the most common cause of adult meningitis. In the immunocompromised patient, however, gram-negative meningitis with Pseudomonas is seen. Haemophilus influenzae is the most common cause in children over a month old. Staphylococcal meningitis is seen with penetrating head wounds. Ref: Brooks G.F. (2013). Chapter 16. Pseudomonads, Acinetobacters, and Uncommon Gram-Negative Bacteria. In G.F. Brooks (Ed), Jawetz, Melnick, & Adelberg's Medical Microbiology, 26e.