Colistin Enhances Rifampicin's Antimicrobial Action in Colistin-Resistant Pseudomonas aeruginosa Biofilms.

Area of Science:

• Microbiology
• Infectious Diseases
• Pharmacology

Background:

• Rising multidrug-resistant Pseudomonas aeruginosa infections necessitate novel therapeutic strategies.
• Antibiotic combinations, particularly with colistin, are being explored to combat resistance.
• Colistin resistance in P. aeruginosa poses a significant clinical challenge.

Purpose of the Study:

• To investigate the efficacy of colistin and rifampicin combinations against planktonic and sessile colistin-resistant P. aeruginosa.
• To evaluate the impact of this combination on dynamic P. aeruginosa biofilms.
• To elucidate the mechanism underlying the synergistic effect of colistin and rifampicin.

Main Methods:

• Formation of dynamic biofilms of both colistin-resistant and colistin-susceptible P. aeruginosa.
• Treatment of biofilms with a combination of colistin and rifampicin.
• Assessment of the killing effect and mechanism of action of the antibiotic combination.

Main Results:

• The colistin-rifampicin combination demonstrated significant killing activity against both colistin-resistant and susceptible P. aeruginosa in biofilms.
• Colistin's action on the bacterial outer membrane appears to enhance rifampicin penetration.
• This effect was observed irrespective of the bacteria's colistin-resistance phenotype.

Conclusions:

• The colistin-rifampicin combination shows potent in vitro activity against P. aeruginosa biofilms.
• This combination represents a promising therapeutic approach for treating infections caused by colistin-resistant P. aeruginosa.
• Further clinical investigation is warranted to validate this combination therapy.