What is the common organism that causes chronic otitis (inflammation of the middle ear) media?

From the Guidelines

Pseudomonas aeruginosa is the most common organism that causes chronic otitis media, as it frequently colonizes the middle ear in chronic infections, particularly in cases with persistent perforations of the tympanic membrane or in ears that have undergone previous surgery. This gram-negative bacterium thrives in moist environments and produces biofilms that make it difficult to eradicate with standard antibiotic therapy 1. Other common pathogens include Staphylococcus aureus, Proteus species, and anaerobic bacteria, but Pseudomonas predominates in chronic cases. The organism can cause extensive tissue damage and bone erosion if left untreated, potentially leading to more serious complications like mastoiditis or intracranial spread.

Some key points to consider in the management of chronic otitis media include:

• The importance of careful cleaning of the ear canal by a healthcare provider before antibiotic administration to remove debris and improve medication penetration 1
• The use of topical fluoroquinolone antibiotics such as ciprofloxacin or ofloxacin ear drops, administered twice daily for 7-10 days, which provide direct delivery of high antibiotic concentrations to the infection site while avoiding systemic side effects 1
• The potential for Pseudomonas infections to be resistant to standard antibiotic therapy, but the high concentrations of topical antibiotics can often overcome this resistance 1
• The need for culture of persistent drainage from the ear canal to help target future therapy and detect pathogens such as fungi and methicillin-resistant Staphylococcus aureus (MRSA) 1

It is essential to prioritize the most recent and highest quality study, which in this case is the 2022 study published in Otolaryngology--head and neck surgery 1. This study provides the most up-to-date guidance on the management of chronic otitis media and highlights the importance of topical antibiotic therapy in the treatment of this condition.

From the FDA Drug Label

Acute Bacterial Otitis Media caused by Streptococcus pneumoniae, Haemophilus influenzae (including beta-lactamase producing strains) or Moraxella catarrhalis (including beta-lactamase producing strains). Acute bacterial sinusitis due to Haemophilus influenzae, Moraxella catarrhalis or Streptococcus pneumoniae. Acute otitis media caused by Haemophilus influenzae, Moraxella catarrhalis or Streptococcus pneumoniae.

The common organisms that cause chronic otitis media are not explicitly stated in the provided drug labels. However, based on the information provided for acute bacterial otitis media, the common organisms that cause otitis media include:

• Streptococcus pneumoniae
• Haemophilus influenzae
• Moraxella catarrhalis 2, 3, 4

From the Research

Common Organisms Causing Chronic Otitis Media

• The major pathogens causing chronic otitis media include:
  • Staphylococcus aureus
  • Pseudomonas aeruginosa
  • Anaerobic bacteria, such as gram-positive cocci, pigmented Prevotella and Porphyromonas sp, Bacteroides sp, and Fusobacterium sp 5, 6
• These organisms can produce beta-lactamase, rendering them resistant to many penicillins 6
• In chronic suppurative otitis media, Pseudomonas aeruginosa and Staphylococcus aureus are most frequently found 5
• The formation of biofilms by these bacteria can contribute to otitis media recurrence and chronicity 7