Oropharyngeal production of pneumococcal capsular antigen and the potential for contamination of expectorated sputum samples in pneumococcal pneumonia.


The presence of pneumococcal capsular antigen (PCA) in the oropharynx was sought in subjects without respiratory tract infection. Saliva specimens from 239 subjects were analysed by counter-current immunoelectrophoresis using 'Omniserum'. 15.5% gave positive reactions but only 24% of positive samples were typable and therefore due to pneumococcal or… (More)