Family Nurse Practitioner Exam

Which pathogen is the least common cause found in community-acquired atypical pneumonia?

1. Moxarella catarrhalis

2. Streptococcus pneumoniae

3. Pseudomonas aeruginosa

4. Mycoplasma pneumoniae

The correct answer is: Pseudomonas aeruginosa

The least common cause found in community-acquired atypical pneumonia is Pseudomonas aeruginosa. Atypical pneumonia typically occurs due to pathogens that do not have the same characteristics as typical bacterial pathogens, which commonly cause lower respiratory infections. Pseudomonas aeruginosa is primarily associated with healthcare-associated infections and is often found in patients with underlying health conditions, such as those with cystic fibrosis or individuals in hospital settings. It is an opportunistic pathogen rather than a common agent of community-acquired infections. In contrast, Mycoplasma pneumoniae is one of the most notable causes of atypical pneumonia, often affecting younger populations and is characterized by a gradual onset of symptoms. Streptococcus pneumoniae, while typically associated with typical pneumonia, can also present atypically; however, it is more prevalent than Pseudomonas in community settings. Moxarella catarrhalis is occasionally implicated in respiratory infections but is not a common cause of pneumonia in general either. Thus, Pseudomonas aeruginosa stands out as being the least likely pathogen to cause community-acquired atypical pneumonia compared to the other pathogens listed.