This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wicks, J H Articles by Krejcarek, G E Search for Related Content PubMed PubMed Citation Articles by Wicks, J H Articles by Krejcarek, G E

Rapid inoculum standardization system: a novel device for standardization of inocula in antimicrobial susceptibility testing.

ABSTRACT

A rapid inoculum standardization system for antimicrobial susceptibility testing without incubation or the conventional turbidity adjustment has been developed. The rapid inoculum standardization system consists of a plastic rod with cross-hatched grooves on one end and a specific nutrient medium in a vial. The crosshatched grooves are designed to pick up and release a known number of viable microorganisms. In use, the end of the rod is touched to five colonies 1 to 2 mm in diameter from a primary agar plate, thus filling the grooves with bacteria. The rod is placed into the vial, and the bacteria are suspended in the medium by agitation with a Vortex Genie Mixer. The resulting suspension contains 5 X 10(7) to 5 X 10(8) CFU/ml for most gram-negative bacilli and gram-positive cocci. Microorganisms such as streptococci that have colonies less than 1 mm in diameter require as many as 10 colonies for an adequate inoculum suspension. Ninety-five commonly encountered bacterial isolates were tested in triplicate by agar plate counts. The resulting overall geometric mean of the agar plate counts was 1.52 X 10(8) CFU/ml for the species tested. We have found that the rapid inoculum standardization system provides a consistent and reproducible method for the standardization of inoculum for antimicrobial susceptibility testing without the incubation period and turbidity adjustment.

This article has been cited by other articles:

• Cantón, R., Pérez-Vázquez, M., Oliver, A., Sánchez Del Saz, B., Gutiérrez, M. O., Martínez-Ferrer, M., Baquero, F. (2000). Evaluation of the Wider System, a New Computer-Assisted Image-Processing Device for Bacterial Identification and Susceptibility Testing. J. Clin. Microbiol. 38: 1339-1346 [Abstract] [Full Text]