Urinary Tract Infection
  • "For the microbiologic diagnosis of urinary tract infection, by definition, there must be >100,000 organisms/cc. This definition is used because of the common contamination of a "clean-catch" urine specimen, especially in females.
    • The photograph above shows the plate from just such a specimen.
  •  It is growing colonies of at least 3 different types (arrows- Gram negative rods (GNR), diptheroids (Dips), and staph coagulase negative (SCN).
    • This culture would be signed out as 'mixed flora, probable contamination'.
  • Certain patients may have asymptomatic bacteruria, with less than 100,000 organisms/cc.
    • Pregnant women are an example of such a patient population. Any number of organisms may be significant.
    • In such a case, it may be worth considering straight catheterization, to obtain an optimal specimen.
    •  However, you must consider the risk that you may introduce organisms by doing a catheterization."
  • 1999 KUMC Pathology and the University of Kansas, used with permission; courtesy of Dr. James Fishback, Department of Pathology, University of Kansas Medical Center.