E-test: a new technique for antimicrobial susceptibility testing for periodontal microorganisms

Area of Science:

• Microbiology
• Periodontology
• Antimicrobial Resistance

Background:

• Periodontal diseases are associated with specific pathogenic microorganisms.
• Accurate antimicrobial susceptibility testing (AST) is crucial for effective treatment.
• The Epsilometer test (E-test) offers a method for direct quantification of antimicrobial susceptibility.

Purpose of the Study:

• To validate the Epsilometer test (E-test) for AST of periodontopathic bacteria.
• To compare E-test results with the established agar dilution method.
• To assess the reliability of E-test for key periodontal pathogens.

Main Methods:

• Collected subgingival plaque samples from periodontitis patients.
• Isolated and identified 60 strains of key periodontal pathogens.
• Performed AST using both E-test and agar dilution methods.
• Tested antibiotics including clindamycin, metronidazole, tetracycline, ciprofloxacin, cefoxitin, and ampicillin.

Main Results:

• The E-test demonstrated good agreement with agar dilution MICs, ranging from 67% to 100%.
• Sensitivity and specificity values for the E-test were high, indicating reliable results.
• High agreement was observed for specific antibiotics like ampicillin, cefoxitin, and metronidazole against various periodontal pathogens.

Conclusions:

• The E-test is a valid and reliable method for antimicrobial susceptibility testing of periodontopathic microorganisms.
• E-test provides accurate quantitative results comparable to the agar dilution method.
• This validation supports the clinical utility of E-test in managing periodontal infections.