What are the common causes of otitis media?

From the Guidelines

Otitis media is commonly caused by bacterial and viral infections, with the most frequent bacterial pathogens being Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, as reported in a recent study 1. The causes of otitis media are related to many factors, including a patient’s immune system, bacterial biofilms, and environmental factors such as frequent exposure to viral and bacterial infections 1. Eustachian tube dysfunction plays a central role, as it prevents proper drainage and ventilation of the middle ear, creating an environment conducive to infection 1. Some key points to consider include:

• Young children have eustachian tubes that are not fully developed, which can lead to middle ear problems 1
• Risk factors include young age, daycare attendance, bottle feeding while lying down, exposure to secondhand smoke, and anatomical differences such as cleft palate
• Seasonal patterns exist with higher incidence during fall and winter months when respiratory infections are more prevalent
• Allergies and enlarged adenoids can also contribute by causing eustachian tube obstruction
• Prompt treatment is important to prevent complications such as hearing loss, tympanic membrane perforation, or spread of infection to surrounding structures It's worth noting that while an older study 1 provides some information on the microbiology of otitis media, the more recent study 1 provides a clearer understanding of the causes and risk factors associated with the condition.

From the Research

Common Etiologies of Otitis Media

• Otitis media is typically caused by viral upper respiratory tract infections and/or bacterial infections 2
• Common viruses associated with otitis media include:
  • Respiratory syncytial virus
  • Rhinovirus
  • Adenovirus
  • Parainfluenza
  • Coronavirus 2, 3
• Predominant bacteria that cause otitis media are:
  • Streptococcus pneumoniae
  • Moraxella catarrhalis
  • Non-typeable Haemophilus influenzae 2, 3, 4, 5, 6
• Other bacteria that may be involved in otitis media include:
  • Alloiococcus otitidis 4
  • Pseudomonas aeruginosa 5
  • Staphylococcus aureus 5
  • Streptococcus pyogenes 5

Viral-Bacterial Interactions

• The risk of acute otitis media differs by the specific viruses and bacteria involved 3
• High respiratory syncytial virus loads are associated with an increased risk of acute otitis media, particularly when combined with Streptococcus pneumoniae or Haemophilus influenzae 3
• The presence of bocavirus and Haemophilus influenzae together is also associated with an increased risk of acute otitis media 3

Bacterial Pathogens in Middle Ear Fluid

• In purulent effusions, one or more bacterial organisms are detected in approximately 90% of samples, with Haemophilus influenzae being the most commonly detected organism 4
• In non-purulent effusions, the most prevalent organism detected is Alloiococcus otitidis, but half of the samples have none of the common otopathogens detected 4