The problem, the consequences, and rapid testing solutions
Community-Acquired Pneumonia (CAP) is a common disease that is associated with considerable mortality and morbidity, and accounts for high antibiotic consumption.1
In the U.S., invasive pneumococcal disease in adults 19-64 years of age decreased from 16 cases per 100,000 in 1998 to 8 cases per 100,000 people in 2019.2 However, pneumonia continues to be a serious public health problem worldwide: 808,000 children under the age of 5 years were killed by pneumonia in 2017.3 The disease also presents a serious health risk to people over 65 years of age and those with pre-existing health risks.3 Although numerous pathogens can cause CAP, Streptococcus pneumoniae remains the leading bacterial cause worldwide and the leading cause of mortality. It is also the most likely pathogen in patients with CAP admitted to the ICU.4
The Problem
Current evidence supports that antibiotics should be administered within 6 hours after the patient arrives at the hospital.5 Data shows that a delay in antibiotic administration in older patients (≥ 65 years of age) is correlated with increased mortality.6 Because results of definitive diagnostic tests for pneumonia are not available for several days, broad-spectrum antibiotics are prescribed. In the U.S., current guidelines recommend testing in severe cases.7
The FDA has licensed three conjugate (PCV13, PCV15 and PCV20) vaccines and one polysaccharide (PPSV23) vaccine for protection against pneumococcal disease.8 However, vaccines are not effective against all pneumococcal strains since vaccines are developed against the most common strains. Consequently, the serotype of an infected and vaccinated person changes over time as the vaccine-evading strain becomes predominant, rendering the vaccine to be less effective over time. The protective efficacy of pneumococcal vaccination in older adults (≥ 65 years of age) has not been firmly established due to a lack of randomized controlled clinical trials in this group, despite being considered a group that is among the most vulnerable to pneumonia.9 Due to the diminished effectiveness of vaccines and an ever-increasing aging population, rapid diagnostic testing is essential to detect positive cases.
The yield of traditional microbiological investigations for diagnosis of CAP is limited for several reasons: routine difficulties in obtaining good-quality sputum and the uncertainty of the value of its culture results, low sensitivity of blood cultures, and administration of antibiotics before sample collection.10
The Consequences
The delay of a definitive and focused diagnosis may cause patients to be at risk for adverse reactions due to the empirical use of broad-spectrum antibiotics. Some broad-spectrum antibiotics (i.e., cephalosporins or fluoroquinolones) used to treat CAP, have been strongly associated with Clostridium difficile associated diarrhea (CDAD) and methicillin-resistant Staphylococcus aureus (MRSA).11
Rapid Testing
Early and rapid diagnosis of CAP would allow more directed therapy and confidence in appropriate treatment for a majority of patients.12 Using an appropriate pathogen-focused antibiotic or narrowing empirical therapy may decrease cost, drug adverse events, and the threat of antibiotic resistance.13
A rapid and simple urine antigen test (UAT), BinaxNOW® Streptococcus pneumoniae based on immunochromatographic technique, is widely available to detect the C-polysaccharide antigen of S. pneumoniae in just 15 minutes. The high specificity, positive predictive value, and positive likelihood ratio makes BinaxNOW® S. pneumoniae a useful tool in the treatment of adult patients with CAP. The BinaxNOW® S. pneumoniae Urinary Antigen Card can be read visually or with the DIGIVAL™.
In one study, the BinaxNOW® UAT was the only diagnostic test positive for S.pneumoniae for 32 patients. Had this test not been available, these patients would have received diagnoses of pneumonia due to atypical pathogens or unknown etiology, and according to current guidelines, would have received broad-spectrum antibiotic therapy. However, these patients fared just as well receiving penicillin.14
The BinaxNOW® S. pneumoniae test is advocated by numerous worldwide CAP guidelines, including IDSA/ ATS, BTS, SPILF and SEPAR. The IDSA/ATS CAP guidelines conclude that only 50% of BinaxNOW® S. pneumoniae UAT positive patients can be diagnosed by conventional methods.15
*Only available in select markets.