Tentative direct antimicrobial susceptibility testing in urine.

Abstract

Tentative direct disk susceptibilities in bacteriuria compared to standard techniques were reevaluated. A sterile cotton swab was saturated with urine and uniformly streaked over the surface of a Mueller-Hinton agar plate. Susceptibility disks were added within 5 minutes and the zone of inhibition around the antibiotic disk was read after 16 to 18 hours of incubation. The tentative direct susceptibilities showed an accuracy of 98.2% compared to standard techniques in 2,906 positive pure cultures. The false-positive rate was 0.53% and the false-negative rate was 0.14%. Results of tentative direct antibiotic susceptibility in bacteriuria are comparable to those of standard techniques and are obtained 24 hours sooner.