Bactericidal effects of antimicrobial agents on epithelial cell-associated Pseudomonas aeruginosa

Area of Science:

• Microbiology
• Pharmacology
• Cell Biology

Background:

• The efficacy of antipseudomonal agents against intracellular bacteria remains unclear.
• Pseudomonas aeruginosa can associate with host epithelial cells, complicating treatment.

Purpose of the Study:

• To evaluate the bactericidal activity of various antipseudomonal antibiotics against cell-associated Pseudomonas aeruginosa.
• To compare the speed and effectiveness of different antibiotic classes in eradicating intracellular bacteria.

Main Methods:

• Infection of Madin-Darby canine kidney (MDCK) and A549 cells with Pseudomonas aeruginosa strains.
• Treatment with ceftazidime, imipenem, meropenem, gentamicin, and ciprofloxacin.
• Assessment of bactericidal activity against cell-associated bacteria within a 2-hour timeframe.

Main Results:

• Beta-lactam antibiotics (ceftazidime, imipenem, meropenem) showed limited bactericidal activity against cell-associated bacteria within 2 hours.
• Gentamicin effectively killed >99% of epithelial cell-associated bacteria at concentrations ≤32 μg/ml.
• Ciprofloxacin exhibited potent and rapid bactericidal activity, killing >99.9% of MDCK cell-associated bacteria at 0.5 μg/ml.

Conclusions:

• Ciprofloxacin possesses the strongest and most rapid bactericidal effect against epithelial cell-associated Pseudomonas aeruginosa.
• The superior activity of ciprofloxacin may be attributed to its potent in vitro efficacy and high epithelial cell penetration.
• Findings suggest ciprofloxacin's potential utility in treating infections involving intracellular Pseudomonas aeruginosa.