Family Nurse Practitioner Exam

What is the most common pathogen associated with otitis externa infections?

1. Streptococcus pyogenes

2. Pseudomonas aeruginosa

3. Haemophilus influenza

4. Moraxella catarrhalis

The correct answer is: Pseudomonas aeruginosa

Pseudomonas aeruginosa is recognized as the most common pathogen associated with otitis externa, commonly referred to as "swimmer's ear." This gram-negative bacterium thrives in moist environments, making the ear canal particularly susceptible to infection, especially following water exposure. Otitis externa typically occurs when the skin in the ear canal is compromised, allowing Pseudomonas to invade and proliferate. This can happen through various means, such as excessive moisture, trauma from cleaning the ear, or skin conditions that disrupt the normal barrier. The symptoms of otitis externa often include pain, discharge, and itching, which can be attributed to the inflammatory response elicited by the infection. In contrast, other bacterial pathogens listed, such as Streptococcus pyogenes, Haemophilus influenzae, and Moraxella catarrhalis, are more commonly linked with conditions like pharyngitis, sinusitis, or otitis media (middle ear infection), rather than otitis externa. Their presence in ear infections is less frequent, and they do not have the same environmental predisposition for infecting the external ear canal as Pseudomonas aeruginosa. Therefore, the prominence of Pseudomonas in otitis externa makes it a