| Infections caused by multidrug-resistant bacteria such as P. aeruginosa are important therapeutic complications. Piperacillin/Tazobactam is considered a safe antimicrobial agent. But we should not ignore
the prevalence of resistant strains to this drug. In this work, a new polymeric micelle composed of
Piperacillin/Tazobactam-loaded Poly (ethylene glycol) methyl ether-block-poly (lactide-co-glycolide)
(PLGA-PEG) was developed to improve the antimicrobial performance of P/T. The SEM and TEM studies
of PLGA-PEG micelle showed, semi-spherical morphology with a mean diameter of below 30 nm. Zeta
potential results indicated that the surface charge of PLGA-PEG micelle was 2.98 mV, while after
encapsulation of P/T, the surface charge decreases to 4.13 mV. Clinical strains of P. aeruginosa were
isolated and their resistance pattern against different antibiotics was evaluated. The MIC of free and P/
T -Loaded PLGA-PEG micelles was determined. Also, the effect of free or P/T micelle against minimal
biofilm eradication concentration and motility inhibition was evaluated. The bacterial isolates were
resistant to most common antibiotics. The MIC of the free drug form and micelle form ranged from 4
to 512 mg/ml and 2 to 256 mg/ml, respectively. Generally, micelle showed more effective antibiofilm
activities, inhibition of bacterial motility and reducing the MIC than that free drug form. |