Avoidance of false-negative blood culture results by rapid detection of pneumococcal antigen
G. W. Fischer, L. P. Smith, V. G. Hemming, R. Longfield, A. A. Valdes-Dapena and J. O. Lopreiato
False-negative blood culture results may occur in children with
pneumococcal bacteremia due to bacterial autolysis. We describe four
patients with pneumococcal bacteremia whose aerobic blood cultures showed
partial or complete autolysis of the pneumococci. Pneumococcal antigen,
however, was rapidly detected in media from the blood culture bottles,
using an agglutination assay. Processing of the media before analysis was
necessary to prevent nonspecific agglutination and to allow the detection
of a specific reaction. It is important that physicians and laboratory
personnel be aware that pneumococci may rapidly autolyze during incubation,
yielding false-negative culture results. Antigen detection methods may
provide rapid and specific identification of the etiologic agent.
