Interpretive criteria and quality control limits for ceftibuten disk susceptibility tests. Collaborative...

Area of Science:

• Microbiology
• Clinical Microbiology
• Antimicrobial Susceptibility Testing

Background:

• Ceftibuten is a third-generation cephalosporin antibiotic.
• Standardized susceptibility testing is crucial for guiding antimicrobial therapy.

Purpose of the Study:

• To evaluate the performance of 30-micrograms ceftibuten disks for in vitro susceptibility testing.
• To propose interpretive criteria for resistance and susceptibility based on zone diameters.

Main Methods:

• In vitro susceptibility testing was performed using 30-micrograms ceftibuten disks.
• Proposed interpretive criteria: Resistance ≤ 17 mm (MIC ≥ 32 µg/mL), Susceptibility ≥ 21 mm (MIC ≤ 8.0 µg/mL).
• A multilaboratory quality control study was conducted.

Main Results:

• The proposed interpretive criteria were evaluated.
• Escherichia coli ATCC 25922 was identified as a suitable quality control strain.
• Recommended zone diameter range for E. coli ATCC 25922 is 29–35 mm.

Conclusions:

• The proposed interpretive criteria for ceftibuten susceptibility testing are validated.
• Ceftibuten disk diffusion testing provides reliable results for guiding antibiotic treatment.
• Standardized quality control with E. coli ATCC 25922 ensures test accuracy.