Quality Control Results for Disk Diffusion AST Using Appropriate ATCC

question 29

Multiple Choice

Quality control results for disk diffusion AST using appropriate ATCC strains of bacteria showed zone size diameters decreasing over time for a few antimicrobials.Which of the following statements is a possible explanation?

• A)Antimicrobial disks were stored in a frost-free freezer.
• B)Concentration of the bacterial inoculum was 5× 10⁵ CFU/mL.
• C)Depth of Mueller-Hinton agar plates measured 3 mm.
• D)Plates were incubated less than 16 hours in ambient air.

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Definitions:

Classical Conditioning

An educational technique involving the repetitive pairing of two stimuli, which results in a reaction initially caused by the second stimulus, being eventually provoked by just the first stimulus.

Neonate

Newborn baby, particularly within the first 28 days of life outside the womb.

Blink

A rapid closing and opening of the eyelid, which is a reflex action protecting the eye from irritants and helping to spread tears over the surface of the eye.

Peripheral Vision

The ability to see objects that are outside the direct line of vision, near the edges of the field of view.