Overview of Susceptibility Testing 

Susceptibility Testing AffiBIOTICS is a critical process in the field of microbiology and infectious diseases. This testing determines the sensitivity or resistance of bacterial strains to specific antibiotics, guiding the selection of the most effective antimicrobial therapy.

Content on Susceptibility Testing 

Methods of Susceptibility Testing

• Disk Diffusion (Kirby-Bauer Test): Involves placing antibiotic-impregnated disks on an agar plate inoculated with the bacteria of interest. The zone of inhibition around the disk is measured to determine susceptibility.
• Broth Microdilution: A standardized amount of bacteria is exposed to varying concentrations of antibiotics in a broth medium. The minimum inhibitory concentration (MIC) is determined by the lowest concentration of antibiotic that prevents visible bacterial growth.
• E-test (Epsilometer Test): A gradient method that combines aspects of both the disk diffusion and broth dilution methods. It uses a plastic strip impregnated with a gradient of antibiotic concentrations to determine the MIC directly on an agar plate.
• Automated Systems: Systems like VITEK 2, MicroScan, and Phoenix automate the process of susceptibility testing, providing rapid and accurate results.

Applications

• Clinical Diagnostics: Used in hospitals and laboratories to guide the treatment of infections.
• Pharmaceutical Research: Assists in the development of new antibiotics by evaluating their efficacy against various bacterial strains.
• Epidemiological Studies: Helps in tracking the emergence and spread of resistant bacteria in communities and healthcare settings.

Challenges and Future Directions

• Resistance Mechanisms: Continuous evolution of bacterial resistance mechanisms necessitates the development of new antibiotics and novel testing methods.
• Standardization: Ensuring consistency and accuracy across different laboratories and testing platforms.
• Rapid Testing: Development of faster methods for susceptibility testing to provide timely results, particularly in critical care settings.