Acinetobacter baummannii is aerobic, Gram negative and multidrug resistant bacterium (MDR) which is the main cause of the hospital acquired infection.Using nanoparticle as antimicrobial agents is a promising method to overcome the threat of MDR bacteria, this is not only because the natural effective properties of these particles against the bacterial cells, but it is also unlikely that microorganisms gain resistant against nanoparticles. In this study, silver nanoparticles (Ag-NPs) and synergistic effect of Ag-NPs with different antibiotics were tested against A. baummannii strain H72721 in Tryptic Soy Broth (TSB). Minimum inhibitory concentration (MIC) of each of the ampicillin, kanamycin, gentamycin and clindamycin on the bacterium was 11 mg/ml, 2 mg/ml, 0.5 mg/ ml, and 0.3 mg/ml respectively. In addition, MIC of the Ag-NPs alone towards the bacterial strain was found as (0.75 mg ml- 1). Interestingly, the inhibitory property of each of the tested antibiotics were greatly improved when they were used in combination with Ag-NPs compare to when they were used alone, and in case of each of the ampicillin and clindamycin the bacterial growth reduced 3 folds. Results from this study are strongly suggesting that Ag-NPs could be provide a successful approach to overcome the problem of MDR bacteria and could use as a superficial treatment for A. baummannii’s infections.

multidrug resistance, minimuminhibitory concentration, silver nanoparticles

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