Auritidibacter ignavus, an Emerging Pathogen Associated with Chronic Ear Infections

Area of Science:

• Microbiology
• Infectious Diseases
• Otolaryngology

Background:

• Auritidibacter ignavus is a rarely reported gram-positive bacterium.
• Chronic ear infections can present with refractory otorrhea and ear canal stenosis.

Purpose of the Study:

• To report the detection of Auritidibacter ignavus in three cases of chronic ear infections in Germany.
• To highlight challenges in the laboratory identification of A. ignavus.
• To emphasize the clinical significance of A. ignavus in refractory otitis externa.

Main Methods:

• Case series describing three patients with chronic ear infections.
• Microbiologic swab specimen analysis for bacterial identification.
• Clinical data collection including symptoms and treatment response.

Main Results:

• Auritidibacter ignavus was detected in three patients with chronic ear infections, refractory otorrhea, and ear canal stenosis.
• Standard matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) failed to identify A. ignavus.
• The bacterium's morphologic similarity to skin flora can lead to misidentification or oversight.

Conclusions:

• A high index of suspicion is necessary for accurate A. ignavus identification.
• A. ignavus should be considered in patients with chronic external otitis unresponsive to standard quinolone therapy.
• Improved diagnostic methods may be needed for reliable detection of A. ignavus.