highlights the details of the organism which help medical technologists in proper identification of bacteria
Staining
A test that provides clinician with therapeutic guidelines , indicates which antibiotic is effective in killing the bacteria
Antibiotic Susceptibility Testing
Type of stains
- Only one stain is used
- All structures are stained with the same color
- Organism should only be observed for size, shape, and uniformity of staining
Simple stain (Methylene Blue)
Type of stains
- Used to distinguish between group of bacteria
- Used to differentiate various type of bacteria that have similar morphologic features
Differential Stain
Reagents used in differential stains
Crystal violet = primary stain
Gram’s iodine = mordant
Alcohol – acetone solution – decolorizer
Safranin = counterstain
▪ Gram – positive = purple/ blue stain
▪ Gram – negative = pink/ red stain
Types of Antimicrobial Assays
This test is Based on growth inhibition surrounding antibiotic – impregnated disks and yields qualitative results (zone of inhibition)
Disk Diffusion Susceptibility Test (Kirby – Bauer Method)
Types of Antimicrobial Assays
Used to determine both the minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) of a sample bacteria and yields quantitative results
Broth Dilution Susceptibility Test
The lowest concentration of antimicrobial agent that inhibits bacterial growth
The lowest concentration of antimicrobial agent that inhibits bacterial growth
