Pneumococcal serotypes in adult lower respiratory tract infections in primary care in Belgium

Objectives 1) To evaluate pneumococcal (=BinaxNOW® S. pneumoniae positive) severe lower respiratory tract infection (SLRTI) within the total number of SLRTI in primary care in Belgium; 2) To evaluate the pneumococcal serotypes using the serotype specific urinary antigen detection (UAD) assay. Methods Multicenter prospective study of patients with SLRTI in primary care practices in Belgium from February 2011 till March 2013. Urine samples were collected from eligible patients. Urine was tested using the BinaxNOW® S. pneumoniae card. Urine samples were shipped to Pfizer Vaccines Research and Early Development lab (Pearl River, PA, USA) for S.pneumoniae UAD assay testing to detect the serotypes present in the 13-valent conjugate pneumococcal vaccine (PCV13). Results 549 patients were enrolled in the study by 38 GPs. Samples from 456 patients were analyzed by the BinaxNow and UAD assay and 434 (95.2%) were negative with both tests. 26 out of 544 cases were positive in the BinaxNow test and 15 out of 456 in the UAD assay. Among the 12 BinaxNOW-positive samples , 5 were positive by UAD. Among the 15 positive UAD samples, 5 were positive with BinaxNOW. Using both BinaxNOW and UAD, the percentage of pneumococcal SLRTI was 4.82% (22/456). Fifteen of the 22 positive cases (68.18%) showed pneumococcal serotypes present in PCV13: Serotypes 1 , 3, 5 and 18C (n=1; 6.67%), serotypes 6A, 7F , 14 (n=2; 13.33%), serotype 19A (n=5; 33.33%). Conclusion One in 20 cases of pulmonary infections observed in primary care is caused by S. pneumoniae . Sixty-eight percent of serotypes causing SLRTI are present in PCV13.