Hidden in plain sight: urinary Cryptococcus neoformans missed by routine diagnostics in a patient with acute leukemia

Ann Clin Microbiol Antimicrob. 2022 Nov 12;21(1):49. doi: 10.1186/s12941-022-00540-4.

Abstract

Cryptococcuria is a rare manifestation of localized cryptococcal disease. We present a case of Cryptococcus neoformans urinary tract infection in an immunocompromised host missed by routine laboratory workup. The patient had negative blood cultures, a negative serum cryptococcal antigen (CrAg), and "non-Candida yeast" growing in urine culture that was initially dismissed as non-pathogenic. The diagnosis was ultimately made by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) from a repeat urine culture after transfer to a tertiary care center. Cryptococcus should be considered in the differential of refractory urinary tract infections growing non-Candida yeast.

Keywords: Cryptoccouria; Cryptococcal antigen; Cryptococcal infection; Cryptococcus neoformans; India-ink; MALDI-TOF MS.

Publication types

  • Case Reports

MeSH terms

  • Candida
  • Cryptococcosis* / diagnosis
  • Cryptococcus neoformans*
  • Humans
  • Leukemia* / complications
  • Leukemia* / diagnosis
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods
  • Urinary Tract Infections* / diagnosis