Disk diffusion susceptibility test interpretive criteria for GR69153, a new catechol-substituted cephalosporin

Area of Science:

• Microbiology
• Antimicrobial Susceptibility Testing

Background:

• Rapidly growing aerobic pathogens pose significant clinical challenges.
• Accurate and efficient antimicrobial susceptibility testing is crucial for effective treatment.

Purpose of the Study:

• To evaluate the efficacy of GR69153 disk diffusion tests for antimicrobial susceptibility.
• To determine optimal criteria for interpreting GR69153 disk diffusion results.

Main Methods:

• Disk diffusion tests using 10- and 30-microgram GR69153 disks were performed.
• Evaluated against 383 isolates of rapidly growing aerobic pathogens.
• Compared disk zone diameters with Minimum Inhibitory Concentrations (MICs).

Main Results:

• High absolute agreement (96.1-98.1%) between MICs and disk zone diameters was observed.
• No false-susceptible results were reported with the proposed interpretation criteria.
• The 30-microgram disk with specific zone diameter breakpoints is recommended.

Conclusions:

• GR69153 disk diffusion testing provides reliable susceptibility results for aerobic pathogens.
• The recommended criteria ensure accurate identification of susceptible and resistant isolates.
• GR69153 exhibits a spectrum of activity comparable to or wider than ceftazidime.