ISNANSETYO, ALIM, MUHTADI., INDAH ISTIQOMAH, NITIMULYOKAMISO HANDOYO, and TRIYANTO. “<strong><em><span style="font-size:9pt;line-height:115%;">In vitro</span></em><span style="font-size:9pt;line-height:115%;"> Activity Test Is a Critical Evaluation to Screen the Potential Biocontrol Agent. We Developed a Selective Medium for Quantitative <em>in vitro</em> Activity Evaluation of Bacterial Biocontrol Agents Against Pathogenic <em>Vibrio</em> in Aquaculture. Sensitivity Test of Bacterial Biocontrol and <em>Vibrio</em> Spp. to Nine Antibiotics Showed That Oxytetracycline Inhibited the Growth of <em>Vibrio</em> spp., But Did Not Inhibit the Growth of the Bacterial Biocontrol. This Selective Inhibition Activity of Oxytetracycline Suggested This Antibiotic Might Be Supplemented to Establish a Selective Medium. The MIC of Oxytetracycline Against <em>V</em>. <em>harveyi</em>, <em>V</em>. <em>parahaemolyticus,</em> and <em>V</em>. <em>algosus</em> Were 120, 250, and 120 </span><span style="font-size:9pt;line-height:115%;font-family:Symbol;">m</span><span style="font-size:9pt;line-height:115%;">g/ml, Respectively. These Concentration Did Not Inhibit the Growth of Bacterial Biocontrols. Therefore, Oxytetracycline Was Supplemented at 250 µg/ml in Zobell Agar Medium. This Medium Was Used As a Selective Medium to Enumerate the Density of Bacterial Biocontrol. <em>In vitro</em> Activity Test of Bacterial Biocontrol (RLP1) Against <em>V</em>.<em> parahaemolyticus</em> Showed That Strain RLP1 at Density of 10</span><span style="font-size:5pt;line-height:115%;">4 </span><span style="font-size:9pt;line-height:115%;">and 10</span><span style="font-size:5pt;line-height:115%;">6</span><span style="font-size:9pt;line-height:115%;"><span> </span>cells/ml Was Able to Kill <em>V</em>. <em>parahaemolyticus</em> During 6 H Incubation. At Lower Density, 10</span><span style="font-size:5pt;line-height:115%;">2 </span><span style="font-size:9pt;line-height:115%;">cells/ml, This Bacterial Biocontrol Agent Was Able to Kill the Pathogenic <em>Vibrio</em> During 12 H Incubation. This Study Discovered a Selective Medium for the Bacterial Biocontrol and <em>Vibrio</em> Spp. and Provided the Results of Its Application in the Evaluation of <em>in vitro</em> Activity of a Bacterial Biocontrol Agent Against <em>V.</em> <em>parahaemolyticus</em>. The Results Also Revealed That Strain RLP1 Is a Potential Bacterial Biocontrol Against Vibriosis in Marine aquaculture.</span></Strong&gt;”. HAYATI Journal of Biosciences 18, no. 3 (1): 129. Accessed May 3, 2024. https://journal.ipb.ac.id/index.php/hayati/article/view/%3Cstrong%3E%3Cem%3E%3Cspan%20style%3D%22font-size%3A9pt%3Bline-height%3A115%25%3B%22%3EIn%20vitro%3C%2Fspan%3E%3C%2Fem%3E%3Cspan%20style%3D%22font-size%3A9pt%3Bline-height%3A115%25%3B%22%3E%20activity%20test%20is%20a%20critical%20evaluation%20to%20screen%20the%20potential%20biocontrol%20agent.%20We%20developed%20a%20selective%20medium%20for%20quantitative%20%3Cem%3Ein%20vitro%3C%2Fem%3E%20activity%20evaluation%20of%20bacterial%20biocontrol%20agents%20against%20pathogenic%20%3Cem%3EVibrio%3C%2Fem%3E%20in%20aquaculture.%20Sensitivity%20test%20of%20bacterial%20biocontrol%20and%20%3Cem%3EVibrio%3C%2Fem%3E%20spp.%20to%20nine%20antibiotics%20showed%20that%20oxytetracycline%20inhibited%20the%20growth%20of%20%3Cem%3EVibrio%3C%2Fem%3E%20spp.%2C%20but%20did%20not%20inhibit%20the%20growth%20of%20the%20bacterial%20biocontrol.%20This%20selective%20inhibition%20activity%20of%20oxytetracycline%20suggested%20this%20antibiotic%20might%20be%20supplemented%20to%20establish%20a%20selective%20medium.%20The%20MIC%20of%20oxytetracycline%20against%20%3Cem%3EV%3C%2Fem%3E.%20%3Cem%3Eharveyi%3C%2Fem%3E%2C%20%3Cem%3EV%3C%2Fem%3E.%20%3Cem%3Eparahaemolyticus%2C%3C%2Fem%3E%20and%20%3Cem%3EV%3C%2Fem%3E.%20%3Cem%3Ealgosus%3C%2Fem%3E%20were%20120%2C%20250%2C%20and%20120%20%3C%2Fspan%3E%3Cspan%20style%3D%22font-size%3A9pt%3Bline-height%3A115%25%3Bfont-family%3ASymbol%3B%22%3Em%3C%2Fspan%3E%3Cspan%20style%3D%22font-size%3A9pt%3Bline-height%3A115%25%3B%22%3Eg%2Fml%2C%20respectively.%20These%20concentration%20did%20not%20inhibit%20the%20growth%20of%20bacterial%20biocontrols.%20Therefore%2C%20oxytetracycline%20was%20supplemented%20at%20250%20%C2%B5g%2Fml%20in%20Zobell%20agar%20medium.%20This%20medium%20was%20used%20as%20a%20selective%20medium%20to%20enumerate%20the%20density%20of%20bacterial%20biocontrol.%20%3Cem%3EIn%20vitro%3C%2Fem%3E%20activity%20test%20of%20bacterial%20biocontrol%20%28RLP1%29%20against%20%3Cem%3EV%3C%2Fem%3E.%3Cem%3E%20parahaemolyticus%3C%2Fem%3E%20showed%20that%20strain%20RLP1%20at%20density%20of%2010%3C%2Fspan%3E%3Cspan%20style%3D%22font-size%3A5pt%3Bline-height%3A115%25%3B%22%3E4%20%3C%2Fspan%3E%3Cspan%20style%3D%22font-size%3A9pt%3Bline-height%3A115%25%3B%22%3Eand%2010%3C%2Fspan%3E%3Cspan%20style%3D%22font-size%3A5pt%3Bline-height%3A115%25%3B%22%3E6%3C%2Fspan%3E%3Cspan%20style%3D%22font-size%3A9pt%3Bline-height%3A115%25%3B%22%3E%3Cspan%3E%C2%A0%3C%2Fspan%3Ecells%2Fml%20was%20able%20to%20kill%20%3Cem%3EV%3C%2Fem%3E.%20%3Cem%3Eparahaemolyticus%3C%2Fem%3E%20during%206%20h%20incubation.%20At%20lower%20density%2C%2010%3C%2Fspan%3E%3Cspan%20style%3D%22font-size%3A5pt%3Bline-height%3A115%25%3B%22%3E2%20%3C%2Fspan%3E%3Cspan%20style%3D%22font-size%3A9pt%3Bline-height%3A115%25%3B%22%3Ecells%2Fml%2C%20this%20bacterial%20biocontrol%20agent%20was%20able%20to%20kill%20the%20pathogenic%20%3Cem%3EVibrio%3C%2Fem%3E%20during%2012%20h%20incubation.%20This%20study%20discovered%20a%20selective%20medium%20for%20the%20bacterial%20biocontrol%20and%20%3Cem%3EVibrio%3C%2Fem%3E%20spp.%20and%20provided%20the%20results%20of%20its%20application%20in%20the%20evaluation%20of%20%3Cem%3Ein%20vitro%3C%2Fem%3E%20activity%20of%20a%20bacterial%20biocontrol%20agent%20against%20%3Cem%3EV.%3C%2Fem%3E%20%3Cem%3Eparahaemolyticus%3C%2Fem%3E.%20The%20results%20also%20revealed%20that%20strain%20RLP1%20is%20a%20potential%20bacterial%20biocontrol%20against%20vibriosis%20in%20marine%20aquaculture.%3C%2Fspan%3E%3C%2Fstrong%3E.