Pneumococcal Pneumonia---Risky Business

The importance of Streptococcus pneumoniae as a pneumonia pathogen is beyond question.S. pneumoniae is regarded as the single biggest cause of community-acquired pneumonia across all age groups and geographic regions of the world.However, diagnosing pneumococcal pneumonia in individual patients can be difficult, mainly due to the inability to obtain specimens from the site of infection and the failure of diagnostic tests to distinguish colonization from infection.Regardless of these shortcomings, newer diagnostics have enhanced understanding of the role of S. pneumoniae in the etiology of pneumonia in several ways.First, they have reinforced the importance of S. pneumoniae as the most commonly identified cause of pneumonia.For example, the latest generation pneumococcal urinary antigen lateral flow tests have improved the ability to diagnose pneumococcal pneumonia in adults.Second, measurement of pneumococcal load provides insights into the pathogenesis of pneumonia and may be helpful in distinguishing colonization from infection.In particular, preliminary data indicates that quantitative PCR testing of upper respiratory tract specimens may have diagnostic utility.Third, newer diagnostics have increased recognition that pneumococcus is often present with other potential pathogens.These observations reinforce the concept that infection with multiple pathogens may be important in the pathogenesis of pneumonia.There is a pressing need for completely new approaches to pneumonia diagnostics, particularly approaches that can distinguish colonising from infecting microorganisms, that can distinguish recent from past infection, that account for host responsiveness, and can utilise samples that are easy to obtain.