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The BBL™ Prompt™ Inoculation System is used to prepare standardized suspensions of bacteria for the Bauer-Kirby disc diffusion antimicrobial susceptibility test procedure. The system may be used for rapidly growing bacteria such as Enterobacteriaceae, Staphylococcus spp., Pseudomonas aeruginosa, Acinetobacter spp., enterococci and some nonenterococcal streptococci. It also may be used for Haemophilus influenzae.

The Bauer Kirby procedure is a standardized method for the determination of antimicrobial susceptibility based on the agar gel disc diffusion principle.^1-3 This method is published as a consensus standard by the National Committee for Clinical Laboratory Standards (NCCLS) and is periodically reviewed and updated.⁴

The inoculum concentration has been shown to be an important factor in obtaining valid results with the Bauer Kirby procedure.^2-5 The original Bauer-Kirby procedure employed inoculum prepared from log phase cultures. This requires incubation in broth for several hours to achieve the desired inoculum density, equivalent to the 0.5 McFarland turbidity standard, which produces approximately 1 x 10⁸ CFU/mL.^3-5 Several studies have subsequently shown that direct standardization of the inoculum, i.e., without incubation, is an acceptable alternative.^5-7 The direct adjustment of inoculum preparation is the preferred method for fastidious organisms that may grow slowly in broth. The M2-T4 edition of the NCCLS disc diffusion standard contained a revised procedure for Haemophilus influenzae, in which a new medium, Haemophilus Test Medium (HTM), was employed.⁸ This procedure recommended matching the inoculum density to the 0.5 McFarland standard using a photometric device.

The BBL Prompt Inoculation System is a device that allows direct standardization of inoculum without adjustment of turbidity or preincubation.^9-11 This method is considered acceptable for routine testing purposes.⁴ It has been shown that the Prompt system is also satisfactory for preparing inoculum for H. influenzae in the Bauer-Kirby procedure.¹²

The Prompt Inoculation System is used as part of a multicomponent diagnostic test. When employed for the NCCLS inoculum preparation procedure, it should produce the results given in the NCCLS standard for the control cultures.⁴

Quality control requirements must be performed in accordance with applicable local, state and/or federal regulations or accreditation requirements and your laboratory's standard Quality Control procedures. It is recommended that the user refer to pertinent NCCLS guidance and CLIA regulations for appropriate Quality Control practices.

For in vitro Diagnostic Use.

1. Colonies must be selected from FRESH culture plates (≤ 24 h).

2. DO NOT FLAME the plastic inoculation wand. It will melt.

3. To avoid contamination, always keep fingers above the ridge on the inoculation wand.

4. Keep wands covered when not in use.

5. Do not use if colonies are very small (< 0.5 mm in diameter).

Observe aseptic techniques and established precautions against microbiological hazards throughout all procedures. After inoculation, the Prompt inoculation tube and wand and other contaminated materials should be sterilized by autoclaving.