This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cystic fibrosis & Sleep apnea, Subject name: Medicine
Which of the following organisms is unlikely to be found in the sputum of patients with cystic fibrosis? 
Select and explain. 
A. Hemophilus influenzae, B. Acinetobacter baumannii, C. Burkholderia cepacia, D. Aspergillus fumigatus
B: Acinetobacter baumannii
Answer: B: Acinetobacter baumannii 
Explanation: In patients with cystic fibrosis, Hemophilus influenzae and Staphylococcus aureus are responsible for early colonisation. Later Pseudomonas is the main organism colonising the airways in 50% of patients, followed by Burkholderia cepacia. Aspergillus fumigatus is the most common fungus that can colonize airways with/ without causing any lung disease. It can be found in airways of normal people as well as cystic fibrosis.