What are the two most common causes of acute bacterial rhinosinusitis?

The most common causes of acute bacterial rhinosinusitis are indeed Streptococcus pneumoniae and nontypeable Haemophilus influenzae. Streptococcus pneumoniae is a frequent pathogen associated with upper respiratory infections and can lead to sinusitis when mucosal inflammation or obstruction occurs. Nontypeable Haemophilus influenzae, which lacks a polysaccharide capsule, is another prevalent organism implicated in cases of rhinosinusitis, particularly in children.

Both of these organisms are frequently isolated in clinical cases of acute bacterial sinusitis and are particularly notable due to their ability to proliferate in the context of pre-existing viral upper respiratory infections, leading to complications like secondary bacterial infections. Understanding the prevalence of these bacteria helps inform appropriate antibiotic treatment decisions and guides clinicians in managing acute bacterial rhinosinusitis effectively.