en Related Fields Related Fields مقاله کامل Full Length/Original Article <div style="text-align: justify;"><span style="font-family:Times New Roman;"><span style="font-size:11pt"><span style="line-height:normal"><b><span style="font-size:10.5pt"><span style="background:white"><span style="color:black">Background:</span></span></span></b>&nbsp;<span style="font-size:10.5pt">Oropharyngeal candidiasis, primarily caused by <i>Candida albicans</i>, is the most common opportunistic fungal infection in patients with head and neck cancer. <span style="background:white"><span style="color:black">The increasing emergence of </span></span></span><span style="font-size:9.0pt"><span style="background:white"><span style="color:black">fluconazole</span></span></span><span style="font-size:10.5pt"><span style="background:white"><span style="color:black"> (FLZ) resistance has led to higher morbidity and mortality rates. <i>Streptomyces</i>, a genus of <i>Actinomycetes</i>, produces bioactive molecules with antimicrobial effects. This study investigated the antifungal potential of <i>S. monomycini</i> strain 615 against </span></span></span><span style="font-size:10.5pt">FLZ</span><span style="font-size:10.5pt"><span style="background:white"><span style="color:black">-resistant <i>C. albicans</i> </span></span></span><span style="font-size:10.5pt">clinical</span><span style="font-size:10.5pt"><span style="background:white"><span style="color:black"> isolates </span></span></span><span style="font-size:10.5pt">in vitro<span style="background:white"><span style="color:black">. </span></span><span style="background:white"></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:normal"><b><span style="font-size:10.5pt"><span style="background:white"><span style="color:black">Methods:</span></span></span></b> <i><span style="font-size:10.5pt">S. monomycini</span></i><span style="font-size:10.5pt"> strain 615 was cultured, and an aqueous crud extract containing its metabolites was prepared. The effects of extract were tested on five FLZ-resistant <i>C. albicans</i> isolates. Key pathogenic factors such as protease activity, biofilm formation, and gene expressions related to virulence (<i>SAP1</i>, <i>SAP2</i>, <i>HWP1</i>, and <i>ERG11</i>) and azole resistance (ERG11) were evaluated. Cytotoxicity of the extract (1.8-0.0008<span style="background:white"><span style="color:black"> &micro;g/ml) was assessed </span></span>on KYSE-30 esophageal epithelial cells using the MTT assay. </span></span></span><br> <span style="font-size:11pt"><span style="line-height:normal"><b><span style="font-size:10.5pt"><span style="background:white"><span style="color:black">Results:</span></span></span></b><span style="font-size:10.5pt"><span style="background:white"><span style="color:black">&nbsp;Strain 615 showed strong antifungal activity with </span></span></span><span style="font-size:9.0pt">minimum inhibitory concentration</span><span style="font-size:10.5pt"><span style="background:white"><span style="color:black"> (MIC) values of 0.0008-0.0035 &micro;g/ml and </span></span></span><span style="font-size:9.0pt">minimum fungicidal concentration</span><span style="font-size:10.5pt"><span style="background:white"><span style="color:black"> (MFC) values of 0.0017-0.0035 &micro;g/ml after 48 hours. The extract significantly reduced ergosterol content by 31.81%, completely inhibited phospholipase and proteinase activities at 0.0035 &micro;g/ml and suppressed biofilm formation at 0.0035-0.0140 &micro;g/ml. Expression of all tested virulence genes decreased except for <i>ERG11</i>, indicating a possible mechanism to overcome azole resistance. The highest extract concentration caused </span></span>76.7<span style="background:white"><span style="color:black">% cytotoxicity in KYSE-30 cells after 72 hours.</span></span><span style="background:white"></span></span></span></span><br> <b><span style="font-size:10.5pt"><span style="background:white"><span style="line-height:115%"><span style="color:black">Conclusion: </span></span></span></span></b><i><span style="font-size:10.5pt"><span style="background:white"><span style="line-height:115%"><span style="color:black">S. monomycini</span></span></span></span></i><span style="font-size:10.5pt"><span style="background:white"><span style="line-height:115%"><span style="color:black"> strain 615 could serve as an alternative or adjunct therapy for FLZ-resistant oropharyngeal candidiasis&nbsp;</span></span></span></span><span style="font-size:10.5pt"><span style="background:white"><span style="line-height:115%"><span style="color:black">in head and neck cancer patients, warranting </span></span></span></span><span style="font-size:10.5pt"><span style="line-height:115%">further research to confirm safety and efficacy.</span></span></span></div> Actinomycosis, Candida albicans, Drug resistance 126 137 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-3575-2&slc_lang=en&sid=1 Mahtab Karami-Feli 0009-0003-0120-7695 No Department of Mycology, Pasteur Institute of Iran, Tehran, Iran Zahra Jahanshiri z_jahanshiri@pasteur.ac.ir 0000-0001-9431-9335 Yes Department of Mycology, Pasteur Institute of Iran, Tehran, Iran Akram Sadeghi 0000-0001-9181-4787 No Department of Microbial Biotechnology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran