Antimicrobial susceptibility testing by measuring bacterial oxygen consumption on an integrated platform

Area of Science:

• Microbiology
• Biochemistry
• Antimicrobial Resistance

Background:

• Cellular respiration, indicated by oxygen consumption, is vital for bacterial metabolism.
• Antimicrobial resistance is a growing global health concern requiring novel diagnostic approaches.

Purpose of the Study:

• To evaluate bacterial oxygen consumption rate (OCR) as a phenotypic indicator for antimicrobial susceptibility testing.
• To rapidly determine minimum inhibitory concentrations (MICs) for antibiotics against E. coli.

Main Methods:

• Utilized photoluminescence-based oxygen sensing in a microchamber format for reduced sample volumes.
• Measured bacterial oxygen consumption rate (OCR) variations upon antibiotic exposure.
• Employed OCR modeling based on exponential bacterial growth to estimate bacterial doubling time.
• Correlated metabolic heat production data from nanocalorimetry with OCR measurements.

Main Results:

• Demonstrated systematic OCR variations in response to antibiotics, enabling rapid MIC determination.
• Successfully determined MICs for ampicillin, ciprofloxacin, and gentamicin within hours.
• Estimated bacterial doubling times under various culture conditions.
• Gained insights into microbial metabolic state and activity by correlating OCR and heat production.

Conclusions:

• Bacterial oxygen consumption rate (OCR) is a viable phenotypic indicator for rapid antimicrobial susceptibility testing.
• This microchamber-based approach offers a faster and more comprehensive method for microbiological studies.
• The integrated system provides deeper insights into microbial metabolic activity and antibiotic response.