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This bacterium is considered one of the most life-threatening bacteria and has been identified as a priority pathogen for research by WHO. Biofilm-producing\n                      <jats:italic>P. aeruginosa<\/jats:italic>\n                      is a concern in many parts of the world due to antibiotic resistance. Alginate also plays an important role in the biofilm formation of\n                      <jats:italic>P. aeruginosa<\/jats:italic>\n                      as well as the emergence of antibiotic resistance in biofilms. In addition, the systems of toxin-antitoxin( TA) play an important role in biofilm formation. Metal nanoparticle(NP) such as zinc oxide (ZnO) also have extensive biological properties, especially anti-biofilm properties. Therefore, this study was conducted in relation to the importance of zinc oxide nanoparticles (ZnO NPs) in biofilm formation and also the correlation of gene expression of TA systems in clinical isolates of\n                      <jats:italic>P. aeruginosa.<\/jats:italic>\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      A total of 52\n                      <jats:italic>P. aeruginosa<\/jats:italic>\n                      isolates were collected from burns (n\u2009=\u200915), UTI (n\u2009=\u200931), and trachea (n\u2009=\u20096) in hospitals in Ilam between May 2020 and October 2020. Biofilm formation was assessed using a microtiter plate assay. MIC and sub-MIC concentrations of ZnO NPs (10\u201330\u00a0nm with purity greater than 99.8%) in\n                      <jats:italic>P. aeruginosa<\/jats:italic>\n                      were determined. Subsequently, biofilm formation was investigated using sub-MIC concentrations of ZnO NPs. Finally, total RNA was extracted and\n                      <jats:italic>RT- qPCR<\/jats:italic>\n                      was used to determine the expression levels of genes of\n                      <jats:italic>mazEF<\/jats:italic>\n                      ,\n                      <jats:italic>mqsRA<\/jats:italic>\n                      , and\n                      <jats:italic>higBA<\/jats:italic>\n                      of TA systems.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Six isolates of\n                      <jats:italic>P. aeruginosa<\/jats:italic>\n                      were found to form strong biofilms. The results showed that ZnO NPs were able to inhibit biofilm formation. In our experiments, we found that the sub-MIC concentration of ZnO NPs increased the gene expression of antitoxins\n                      <jats:italic>mazE<\/jats:italic>\n                      and\n                      <jats:italic>mqsA<\/jats:italic>\n                      and toxin\n                      <jats:italic>higB<\/jats:italic>\n                      of TA systems treated with ZnO NPs.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>\n                      In the present study, ZnO NPs were shown to effectively inhibit biofilm formation in\n                      <jats:italic>P. aeruginosa.<\/jats:italic>\n                      Our results support the relationship between TA systems and ZnO NPs in biofilm formation in\n                      <jats:italic>P. aeruginosa<\/jats:italic>\n                      . Importantly, the expression of antitoxins\n                      <jats:italic>mazE<\/jats:italic>\n                      and\n                      <jats:italic>mqsA<\/jats:italic>\n                      was high after treatment with ZnO NPs, but not that of antitoxin\n                      <jats:italic>higA<\/jats:italic>\n                      .\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s12941-023-00639-2","type":"journal-article","created":{"date-parts":[[2023,10,5]],"date-time":"2023-10-05T10:01:47Z","timestamp":1696500107000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":48,"title":["Effect of ZnO nanoparticles on biofilm formation and gene expression of the toxin-antitoxin system in clinical isolates of Pseudomonas aeruginosa"],"prefix":"10.1186","volume":"22","author":[{"given":"Hassan","family":"Valadbeigi","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nourkhoda","family":"Sadeghifard","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vahab Hassan","family":"Kaviar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohammad Hossein","family":"Haddadi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sobhan","family":"Ghafourian","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abbas","family":"Maleki","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2023,10,5]]},"reference":[{"key":"639_CR1","doi-asserted-by":"publisher","first-page":"2671","DOI":"10.3389\/fmicb.2017.02671","volume":"8","author":"C-Y Chang","year":"2018","unstructured":"Chang C-Y. 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