Diagnosis and Medical Management


A definitive diagnosis of infection with Streptococcus pneumoniae generally relies on isolation of the organism from blood or other normally sterile body sites. Tests are also available to detect capsular polysaccharide antigen in body fluids.

A urinary antigen test based on immunochromatographic membrane technique to detect the C-polysaccharide antigen of Streptococcus pneumoniae as a cause of community-acquired pneumonia among adults is commercially available. The test is rapid and simple to use, has a reasonable specificity in adults, and has the ability to detect pneumococcal pneumonia after antibiotic therapy has been started.

Available data show that pneumococcal bacteria are resistant to one or more antibiotics in 30% of cases.

Medical Management

Available data pdf icon[5.24 MB, 114 pages] demonstrate that in severe S. pneumoniae cases, the bacteria are fully resistant to one or more clinically relevant antibiotics.

Following the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in 2000, antibiotic resistance initially declined before increasing again. Then, in 2008, the Clinical and Laboratory Standards Institute (CLSI) changed the definition of penicillin resistance so that a much larger proportion of pneumococci are now considered susceptible to penicillin. The revised susceptibility breakpoints for Streptococcus pneumoniae were the result of a reevaluation that showed clinical response to penicillin was being preserved in clinical studies of pneumococcal infection, despite reduced susceptibility response in vitro.

For more information on medical management of pneumonia, please see the guidelines below.


Community-Acquired Pneumonia (CAP)

Healthcare-Associated Pneumonia (HCAP)

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Page last reviewed: September 6, 2017