Investigation of the effectiveness of kiwi seed oil against A.baumannii isolates alone and in combination with colistin

Objective: There is an increasing interest in plants used for therapeutic purposes in the world. Despite the increase in antibiotic resistance in bacteria, it is seen that there is no resistance against herbal products with antimicrobial properties. In this study, it was aimed to investigate the antimicrobial and combined effect of colistin and oil obtained from the seed of the kiwifruit (Actinidia deliciosa), which has been grown in our country due to its favorable climate, although it is a tropical fruit. To evaluate the antimicrobial effect of kiwifruit seed oil, the clinical isolate of Acinetobacter baumannii, which is an important source of nosocomial infections due to developing multidrug resistance, was tested. Method: The minimum inhibitory concentration (MIC) values of kiwifruit seed oil were determined by liquid microdilution and the combined effect of in vitro colistin antibiotic by checkboard microdilution method. The effect of the combination of kiwifruit seed oil and colistin antibiotic was evaluated by the fractional inhibitory concentration (FIC) index. Results: The antimicrobial effect of kiwifruit seed oil against A.baumannii isolates was determined. When the combined effect of colistin and kiwifruit seed oil was evaluated in five colistin-resistant A.baumannii isolates, an additive effect was found in all isolates. Conclusion: This is the first study to examine the antimicrobial effect of kiwi seed oil in A.baumannii isolates and the combined effect with any antibiotic. Kiwi seed oil can increase the effect of colistin on A.baumannii isolates. It can be a potential alternative method to prevent or treat infections that develop in medicine. Further studies are needed to fully understand the reason for this effect. In future studies, different bacterial strains or combined effects can be investigated with different antibiotics.