Single cell growth rate and morphological dynamics revealing an "opportunistic" persistence

Area of Science:

• Microbiology
• Bacterial Physiology
• Antibiotic Resistance

Background:

• Bacterial persistence allows a small cell fraction to survive high antibiotic doses.
• Studying single-cell dynamics is crucial for understanding persistence.
• Existing methods often lack the resolution for dynamic single-cell analysis.

Purpose of the Study:

• To develop a system for long-term, single-cell tracking under antibiotic stress.
• To investigate the mechanisms behind bacterial persistence.
• To discover novel forms of antibiotic resistance.

Main Methods:

• Developed a gradient microfluidic system for single-cell analysis.
• Employed time-lapse imaging to monitor bacterial morphology and growth.
• Calculated growth rates based on cell mass and number variations.
• Utilized E. coli and Comamonas denitrificans with amoxicillin.

Main Results:

• Achieved good agreement between IC50 values determined by cell mass and cell number.
• Observed morphological dynamics alongside growth rates.
• Discovered a new persistence form termed 'opportunistic persistence'.

Conclusions:

• Normal bacterial cells can acquire amoxicillin persistence by utilizing lysed cell cytoplasm.
• Opportunistic persistence offers new insights into biofilm resistance.
• Findings may impact understanding of antibiotic effects on environmental bacteria.