Investigation of antibiotic resistance genes in multiple drug resistant Acinetobacter baumannii strains and determination of the effect of some plant extracts on isolates

The widespread use of antibiotics has increased resistance and spread among pathogenic bacteria and has become an important problem today. Infections caused by multi-drug resistant Acinetobacter baumannii, one of these pathogens, have been identified in many countries. There are studies in the literature on the presence of molecular mechanisms that cause resistance in isolates with antibiotic resistance and to investigate plants containing secondary metabolites that may be antibacterial agents. In this study, we investigated the presence of β-lactamase resistance genes and class 1 integrons in multi-drug resistant A. baumannii isolates; and also to find the minimum inhibition concentrations of Morus alba (Mulberry), Zingiber officinale (Ginger), Vaccinium myrtillus (Blueberry-Ligarba), Rosa canina (Rosehip), Hypericum perforatum (Centaury), Lycium barbarum (Goji bery), Aquilaria agallocha (Udu Hindi), Nigella sativa (Nigella), Echinacea purpurea (Echinacea) extracts against these isolates. 41 A. baumannii isolates were isolated from various clinical samples of patients treated in the intensive care unit of Rize Training and Research Hospital. PZRs were performed using primers of blaVIM, blaNDM, blaIMP, blaGES, blaCTXM-1, blaCTXM-2, blaOXA-58, blaOXA-23, blaOXA-51 and Class 1 integron. Methanol was used as solvent for the preparation of plant extracts. Six different isolates (AB38, AB43, AB45, AB46, AB59, AB69) were selected from multiple drug resistant isolates according to their resistance profiles. MIC values of the plant extracts were determined by liquid microdilution method. Experiments on 96-well plates were performed in 3 replicates. According to PCR results, blaOXA-51 gene was detected in all isolates. The presence of blaOXA-23 gene was found in 38 of the isolates. blaCTXM-1 was detected in 36 isolates, blaCTXM-2 was detected in 18 isolates and blaGES 1 was detected in isolates. The blaVIM, blaNDM, blaIMP and blaOXA-58 genes were not detected in any isolates. The presence of class 1 integrons was observed in 34 isolates. The antibacterial effects of the plant methanol extracts were evaluated and the MIC of the nigella extract was determined to be 20 mg/ml against all isolates. Goji bery extract showed 35 mg / ml MICs against AB38, AB43, AB46, AB59 isolates. In addition, the MIC of this extract was found to be 17.5 mg/ml against AB45 and AB69. The MIC of centaury extract was determined to be 10 mg/ml against AB38, AB43, AB45 isolates. MIC values of ginger extract were 30 mg/ml against AB38 and AB45 isolates and 15 mg/ml for AB46 and AB59 isolates. The antibacterial effect of udu hindi and blueberry extracts against tested isolates was not determined. The presence of β-lactamase encoding genes and class 1 integrons in A. baumannii shows that resistance genes and integrons remain responsible for antibiotic resistance. The determination of the antibacterial effects of methanol extracts of preferred plants against A. baumannii isolates explains the importance of the need to investigate the antibacterial activities of plants in the fight against antibiotic resistance