Septicemia due to DF-2. Cause of a false-positive cryptococcal latex agglutination result

A previously healthy 26-year-old man presented with fever, headache, skin rash, and thrombocytopenia. Cultures of blood and cerebrospinal fluid yielded a fastidious gram-negative bacillus, identified as DF-2. A unique feature of this case was the presence of a false-positive latex agglutination result for cryptococcal antigen in the cerebrospinal fluid in the absence of pleocytosis. Additional laboratory studies, which included indirect immunofluorescence and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, however, failed to reveal common antigenic surface components between these organisms.