Evaluation Of Meropenem-Resistance Genes Expression In Acinetobacter Baumannii Isolates Using Nanobiopolymer Composite (Histidine:Meropenem:Nanochitosan) And Its Cytotoxicity And Bioassay

Abstract

The aim of the study is to evaluate the effect of the nanobiopolymer composite Hisidine:Memropenem:Nanachitosan (His:Mem:NC)) on the efficiency of expressionMem-resistance genes in Mem-resistant Acinetobacter baumannii isolates and their cytoxicity on cell lines in addition to its bioassay on lab. Animals. Sixty-five isolates of multidrug resistant of A. baumannii were selected out of 240 isolates collected from variousinfection sources includedthe wounds, sputum, urine, blood, andmedical device.The selected isolates have minimum inhibitory concentration (MIC) of Mem more than 16μg/ml. Nineteen isolates were selected that have MICof Mem ranged between 64 -256 μg/ml and MBC 128-512 μg/ml. The genes most associated with Mem-resistance were selected in A. baumannii bacterium, which are the OXA genes (blaOXA23, ISAbablaoxa23, ISAbablaOXA51). Allisolates were identified as Acinetobacter baumanniiusing 16srRNA gene amplification technique. The results showed that 16 (84.21%)harbor the blaOXA23gene; ISAbablaoxa23,14(73.6%) and ISAbablaOXA51,13(68.4%) with the molecular size of 501,321and 227 bp, respectively. Nanobiopolymer composite of His:Mem:NCwas prepared andcharacterization (as mentioned in research published in Turkish Journal of Physiotherapy and Rehabilitation; 32(3), 2021). It was foundthat the MIC of Mem in nanobiopolymer compositereduced to ≤8μg/ml.Gene expression level of blaOXA23,ISAbablaOXA23 and ISAbablaOXA51genes was measured by real time quantitative polymerase chain reaction (RT-qPCR) before and after 4 and 8 hr of treatment the isolates withnanobiopolymer. The Ct value of the blaOXA23, ISAbablaOXA23 and ISAbablaOXA51 genes isolates after treated with nanobiopolymer, at the selected MIC, It failed to express after 4 hours of treatment, and all isolates did not express sequentially after 8 hours of treatment, depending on the values of ct and 2 folds..It was found thatthe inhibition percent of cancer cell line (HepG2) ranged between 5.1% - 57.4% after treating with nanobiopolymer at concentration 6.25- 400 μg/ml, while the percentage of inhibition fornormal cell line (WRL68) ranged between 5.1% - 26.1% at the same concentrations. The bioassay of nanobiopolymer composite on rabbits infected with bacteria that suffering from septicemia and wound inflammation, has played a major role in inhibiting the growth of bacteria and they recovered and healing the wounds in comparison with untreated rabbits which appeared swelling and suppuration in the wound area and they died after 6, 7 and 11 days after infection.Also, theblood analysis,liver, and renal functiontests results of infected and treated rabbits by nanobiopolymer were like those of the control rabbits.