[Value of media containing chromogenic substrates for the identification and the listing of urinary bacteria]

Performance in terms of enumeration, growth and identification with a new culture medium (CPS ID2, bioMérieux) was evaluated using 405 urine samples and 244 collection strains. The CPS ID2 medium contains chromogenic substrates enabling the detection of 4 bacterial enzymes which leads to the identification of colonies: Escherichia coli, Proteus mirabilis, Proteus-Morganella-Providencia and enterococci. No discrepancies in the enumeration were observed with the collected strains and urine samples. Sensibility and specificity of the identification of Proteae taxa (TDA +) and enterococcal taxa (Gram positive cocci and beta-glucosidase +) was 100% using urine samples and 95.1% of E. coli strains (beta-glucuronidase +, indole +) are detected. Routine use of this new medium for the bacterial examination of urine is satisfactory and an ultra-violet lamp is no longer required for reading as was the case previously with media containing fluorogenic substrates.