Rapid diagnosis of gram negative urinary infections: identification and antimicrobial susceptibility testing in 24 hours.

A rapid method for diagnosing urinary tract infections, using identification and antimicrobial susceptibility testing that can be carried out in 24 hours, was devised. The method relies on direct inoculation of diluted urine (1/500) in the API 20 E and API ATB systems. Urine was simultaneously cultured on Columbia blood agar and on Drigalski agar to control the purity and for purposes of comparison. The results of this method and those obtained with a conventional method were compared by analysing 1352 urines. The results showed that all of the organisms were correctly identified using the conventional method, and susceptibility testing (rapid method) gave results that agreed with those of the classical method in 94% of cases, with major discrepancies in only 0.08% of cases. The rapid method applies only to monomicrobial infections.