Co-encapsulation of gallium with gentamicin in liposomes enhances antimicrobial activity of gentamicin against Pseudomonas aeruginosa

• Published in: Journal of antimicrobial chemotherapy 2008-12, Vol.62 (6), p.1291-1297
• Main Authors: Halwani, M., Yebio, B., Suntres, Z. E., Alipour, M., Azghani, A. O., Omri, A.
• Format: Article
• Language: English
• Subjects: Acyl-Butyrolactones - metabolism; Agrobacterium tumefaciens; Agrobacterium tumefaciens - growth & development; aminoglycosides; Anti-Bacterial Agents - metabolism; Anti-Bacterial Agents - pharmacology; antibiotics; Antibiotics. Antiinfectious agents. Antiparasitic agents; Biofilms; Biofilms - drug effects; Biological and medical sciences; Cell Line; Cell Survival; Comparative studies; Cystic fibrosis; Cystic Fibrosis - complications; Drug Synergism; Epithelial Cells - microbiology; Gallium - metabolism; Gallium - pharmacology; Gentamicins - metabolism; Gentamicins - pharmacology; Humans; Liposomes - metabolism; Medical sciences; Microbial Sensitivity Tests; Microbial Viability; Microbiology; Pharmacology; Pharmacology. Drug treatments; Pseudomonas aeruginosa; Pseudomonas aeruginosa - drug effects; Pseudomonas aeruginosa - isolation & purification; Pseudomonas Infections - microbiology; quorum sensing; Sputum - microbiology; toxicity; Trypan Blue - metabolism
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/dkn422

Objectives The aim of this study was to enhance the antimicrobial efficacy of a liposomal gentamicin formulation with gallium metal (Lipo-Ga-GEN) against clinical isolates of Pseudomonas aeruginosa. Methods Sputum isolates of P. aeruginosa from cystic fibrosis patients were used to determine the MIC and MBC of Lipo-Ga-GEN. P. aeruginosa biofilms were formed and used to compare the minimum biofilm eradication concentration of the conventional drugs with that of Lipo-Ga-GEN. Quorum sensing (QS) molecule reduction of P. aeruginosa was determined by monitoring N-acyl homoserine lactone production using Agrobacterium tumefaciens reporter strain (A136). Viability of the cultured human lung epithelial cells (A549) was determined by Trypan Blue assay in order to assess Ga toxicity. Results MIC and MBC values indicated that gentamicin was more effective against a highly resistant strain of P. aeruginosa (PA-48913) when delivered as a Lipo-Ga-GEN formulation (256 mg/L free gentamicin versus 2 mg/L Lipo-Ga-GEN). Lipo-Ga-GEN was the only formulation that completely eradicated biofilms and blocked QS molecules at a very low concentration (0.94 mg/L gentamicin). The decrease in cell viability was less in A549 cells exposed to Lipo-Ga, suggesting that encapsulated Ga is safer. Conclusions The results clearly indicate that the Lipo-Ga-GEN formulation is more effective than gentamicin alone in eradicating antibiotic-resistant P. aeruginosa isolates growing in a planktonic or biofilm community.