Zinc oxide nanoparticles impact the expression of the genes involved in toxin–antitoxin systems in multidrug‐resistant Acinetobacter baumannii

Abstract The aim of this study was to investigate the effect of zinc oxide nanoparticles (ZnO‐NPs) on the expression of genes involved in toxin–antitoxin (TA) systems in multidrug‐resistant (MDR) Acinetobacter baumannii . Seventy clinical isolates of A. baumannii were collected from variuos clinical samples. Antimicrobial susceptibility test was determined by disk diffusion. Type II TA system‐related genes including GNAT , XRE ‐like, hipA , hipB , hicA , hicB were screened using polymerase chain reaction (PCR). ZnO‐NPs prepared and characterized by field emission scanning electron microscopy and X‐ray diffraction. MIC of ZnO‐NPs of A. baumannii isolates was performed using the microdilution method. The expression of type II TA systems‐related genes were assessed with and without exposure to ZnO‐NPs using real‐time PCR. The highest rate of resistance and sensitivity was observed against cefepime (77.14%), and ampicillin/sulbactam (42.85%), respectively. All A. baumannii isolates were considered as MDR. In this study, three TA loci were identified for A. baumannii including GNAT/XRE‐like, HicA/HicB, and HipA/HipB and their prevalence was 100%, 42%, and 27.1%, respectively. There was no significant relationship between the prevalence of these systems and the origin of A. baumannii . Our data showed significant correlations between the presence of HicA/HicB system and resistance to ceftazidime, meropenem, imipenem, and cefepime ( p < 0.05), and the presence of HipA/HipB system and resistance to ceftazidime, meropenem, imipenem, and cefepime ( p < 0.05). In presence of ZnO‐NPs, the expression of all studied genes decreased. GNAT and hicB showed the highest and lowest expression changes by 2.4 folds ( p < 0.001) and 1.3 folds ( p < 0.05), respectively. This study demonstrates the promising potential of nanoparticles to impact the expression of the genes involved in TA Systems. So, the application of ZnO‐NPs may be helpful to design target‐based strategies towards MDRs pathogens for empowered clinical applications by microbiologists and nanotechnologists.