High temperature induced antibiotic sensitivity changes in Pseudomonas aeruginosa

Area of Science:

• Microbiology
• Bacteriology
• Antibiotic Resistance

Background:

• Pseudomonas aeruginosa exhibits resistance to numerous antibiotics.
• Understanding mechanisms of antibiotic resistance is crucial for developing effective treatments.

Purpose of the Study:

• To investigate the effect of elevated growth temperature (46°C) on the sensitivity of Pseudomonas aeruginosa to various antibiotics.
• To elucidate the impact of temperature on bacterial cell wall and membrane permeability.

Main Methods:

• Culturing Pseudomonas aeruginosa at 46°C and 37°C.
• Testing antibiotic susceptibility at different temperatures.
• Analyzing cell wall composition, specifically lipopolysaccharide (LPS) content and aggregation.
• Assessing the role of EDTA in enhancing antibiotic penetration.

Main Results:

• Pseudomonas aeruginosa grown at 46°C showed increased sensitivity to several antibiotics.
• Cell wall-acting antibiotics required pre-incubation at 46°C before temperature shift.
• Elevated temperature reduced lipopolysaccharide (LPS) content by 40% and altered LPS aggregation.
• Growth at 46°C increased permeability of the outer cell wall, partly due to LPS release.

Conclusions:

• Increased growth temperature (46°C) can restore antibiotic sensitivity in Pseudomonas aeruginosa.
• Temperature-dependent alterations in the outer cell wall, particularly LPS structure and release, are key to this phenomenon.
• Targeting cell wall permeability offers a potential strategy to overcome antibiotic resistance.