Which of the following conditions is classified as an invasive pneumococcal disease?

Invasive pneumococcal disease refers to infections caused by the bacteria Streptococcus pneumoniae that lead to severe illness and are characterized by the presence of the bacteria in normally sterile sites of the body. Meningitis is classified as an invasive pneumococcal disease because it involves the inflammation of the protective membranes covering the brain and spinal cord, with the bacteria typically detected in the cerebrospinal fluid. This condition signifies severe infection and can lead to serious complications, highlighting its invasive nature.

In contrast, conditions such as sinusitis, pneumonia without bacteremia, and otitis media are generally not considered invasive pneumococcal diseases because they occur in less sterile environments and do not typically involve the systemic spread of the bacteria or significant complications associated with their presence in the bloodstream or central nervous system. While these conditions can still be caused by Streptococcus pneumoniae, they do not meet the criteria for invasiveness defined by the presence of the bacteria in sterile sites and associated severe clinical outcomes.