J Lab Med Qual Assur.  2004 Dec;26(2):233-237.

Utility of CHROMagar Orientation Medium for Urine Cultures

• Kim TK
• Kim YM
• Park MJ
• Song W

Abstract

BACKGROUND: Urine cultures are among the most numerous of culture types for microbiology studies. In this study, we evaluated the utility of CHROMagar Orientation (CO; Becton Dickinson, Cockeysville, MD, USA), a new chromogenic medium, for the detection, enumeration, and presumptive identification of urinary tract pathogens.
METHODS
The 438 clinical urine samples sent for routine culture were plated onto CO and Bi-plate (blood/MacConkey agar). We compared the detection and enumeration of potential pathogens, and the agreement between presumptive identification directly from CO and the confirmative identification, which was performed using conventional biochemical tests and Vitek system.
RESULTS
The detection rate of urinary tract pathogens on all two media, CO and Bi-plate were nearly identical. The enumeration of colony counts was consistent on the two media for 102 of the 108 (94%) microorganisms. Colony color and morphology on CO accurately differentiated Escherichia coli and Enterococcus spp. The overall agreement of presumptive identification on CO was 91 of the 108 (84%).
CONCLUSION
The CO enabled accurate detection, count determination, and presumptive identification of common urinary pathogens, both in pure and mixed cultures.

Keyword

CHROMagar Orientation; Urine culture; Presumptive identification

MeSH Terms

Enterococcus
Escherichia coli
Urinary Tract