en <span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><b><span lang="EN-GB" style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif"><span style="color:#f79646">Aims: </span></span></span></b><span lang="EN-SG" style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif">Biofilm formation by bacteria causing healthcare-associated infections poses significant challenges in healthcare and clinical environmental settings, as these biofilms contribute to the emergence of antimicrobial resistance, chronic infections, and contamination of medical equipment, complicating infection control and sanitation strategies. This study investigated the biofilm development of <i>Acinetobacter baumannii</i>, <i>Klebsiella pneumoniae</i>, <i>Pseudomonas aeruginosa</i>, and <i>Burkholderia cepacia</i> following exposure to three disinfectant formulations at different concentrations.</span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><b><span style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif"><span style="color:#f79646">Materials & Methods:</span></span></span></b><span style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif"> This experimental study was done on </span></span><span style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif">40 bacterial isolates collected from various hospital surfaces and medical equipment from different hospitals in Medical City in Baghdad</span></span><span lang="EN-SG" style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif">. The first disinfectant comprised 45% ethyl alcohol, 5% isopropyl alcohol, and dodecyl dimethyl ammonium chloride. The second formulation included quaternary ammonium propionate, chlorhexidine digluconate, and a 2% glutaraldehyde solution. The third consisted of 10% dodecyl dimethyl ammonium chloride and 2% benzalkonium chloride.</span></span> <span style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif">Biofilm formation was assessed using the Crystal Violet assay. Data were analyzed by SPSS 20. </span></span><span lang="EN-SG" style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif"></span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><b><span style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif"><span style="color:#f79646">Findings:</span></span></span></b> <span lang="EN-SG" style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif">Most bacterial strains exhibited moderate to strong biofilm formation across all treatments, with some instances of weak biofilm development noted after the application of the second disinfectant. This suggests that disinfectant efficacy against biofilm-associated bacteria remains limited. </span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><b><span style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif"><span style="color:#f79646">Conclusion:</span></span></span></b><span style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif"> Most bacterial strains exhibit moderate to strong biofilm formation across all treatments</span></span><span lang="EN-SG" style="font-size:10.0pt"><span style="font-family:&quot;Cambria&quot;,serif">.</span></span></span></span></span><br> &nbsp; Biofilm,Healthcare-Associated Infection,Disinfectant,Quaternary Ammonium Compounds (QACs),Ethanol, 75 82 http://ijwph.daneshafarand.org/browse.php?a_code=A-10-2290-1&slc_lang=en&sid=3 O.T. Abbas 1003194753284600379636 1003194753284600379636 Yes Department of Biology, Faculty of Science, University of Baghdad, Baghdad, Iraq A.J. Mohammed 1003194753284600379635 1003194753284600379635 No Department of Biology, Faculty of Science, University of Baghdad, Baghdad, Iraq