Klebsiella capsular
antigen (KCA) was detected in serum by counterimmunoelectrophoresis in 8 of 31 patients with klebsiella
bacteremia, in two nonbacteremic patients with
pneumonia and
meningitis, respectively, and in the cerebrospinal fluid only of 1 of the 31 bacteremic patients. It was also detected in cerebrospinal fluid, urine (two patients each)
empyema fluid, and
abscess drainage (one patient each). Patients whose
bacteremias were associated with a discernible tissue focus (e.g.,
pneumonia) tended to have detectable serum KCA more often than those with "primary
bacteremia." A fatal outcome occurred in six of nine
bacteremia patients with detectable serum KCA compared with 4 of 22 without demonstrable
antigen (P < 0.05). Persistent antigenemia and antigenuria aided in the diagnosis of perinephric
abscess in one patient, and increasing levels of serum KCA anticipated treatment failure in another patient with
pneumonia. The presence of detectable KCA in the serum of patients infected with klebsiella thus appeared to correlate with severity of
infection, with persistence of active foci, and with a poorer prognosis than in those patients who had no detectable
antigen. Whether the presence of this
antigen itself plays any pathogenic role needs to be further clarified.