Question

A 45 year old man has otitis externa. Likely causative pathogens include all of the following except?

1) Staphylococcus aureus
2) Pseudomonas aeruginosa
3) Streptococcus pneumoniae
4) Haemophilus influenzae

Answer 1

Among the given options, Streptococcus pneumoniae is not a likely causative pathogen of otitis externa; it is instead more associated with acute otitis media.

Step-by-step explanation:

The causative pathogens of otitis externa (swimmer's ear) typically include Pseudomonas aeruginosa and Staphylococcus aureus. These organisms thrive in moist environments and are common causes of infections in the outer ear canal.

Streptococcus pneumoniae and Haemophilus influenzae, however, are more commonly associated with acute otitis media (AOM), which is an infection of the middle ear, rather than otitis externa. Therefore, among the options provided, Streptococcus pneumoniae is not likely a causative pathogen of otitis externa in a 45-year-old man.