Introduction: Today, one of the most important challenges of the therapeutic system is the resistance of bacteria against different antibiotics especially in intensive care units which lead to an increase in hospitalization time and the patients’ expenses. Acinetobacter baumannii is one of the most significant contaminating bacteria in intensive care units which has exhibited resistance against different antibiotics in recent years. The aim of this study was to investigate the synergism effect of the silver nanoparticles with the shallot and nettle alcoholic extracts against the standard and multidrug resistant A. baumannii isolates.
Materials and Methods: Samples were collected from intensive care units and the A. baumannii isolates were identified using biochemical tests. Then, the antibiogram test was carried out for each isolate. The antibacterial effect of nanoparticles, shallot and nettle extracts was evaluated singularly and in combination with each other against standard and resistant A. baumannii isolates. Measuring the diameter of inhibited growth zone, MIC, MBC and checkerboard tests were conducted for each isolate.
Results: The results showed that the silver nanoparticles, shallot and nettle alcoholic extracts each had antibacterial property against the standard and resistant A. baumannii isolates. The mixture of the nettle extract with silver nanoparticles had a synergism effect against the standard and resistant isolates and the mixture of the shallot extract with silver nanoparticles had an additive effect against A. baumannii isolates.
Conclusions: Due to the increase of antibiotics resistance and the resistance to the pathogenic bacteria especially in intensive care units, it is necessary to find effective and accessible substances to destroy the resistant bacteria and reduce the mortality rate of patients. The results of the present study revealed that the antibacterial property of the shallot and the nettle alcoholic extracts could increase the antibacterial property of the silver nanoparticles. As a result, these can be used for disinfecting different wards of a hospital, in particular, the intensive care units.