Antibacteria and antibiofilm activities of gram positive bacteria isolated from intestine of sea cucumber (stichopus horrens)

Abstract

There was 10 Gram positive bacteria were isolated from this study (SCI, SC2, SC3, SC4, SC5, SC6, SC7, SC8 SC9 and SCIO). In primary antibacterial assay bacteria SCl exhibited moderate activity against all Gram negative targets used with range of inhibition zone between 1 l-14mm. While the other sample also showed activity against some of Gram negative and positive bacteria with range of inhibition zone between 9-15mm. Based on primary screening bacteria SCl, SC3 and SC9 were selected for second screening in attempt to obtain the minimal inhibition concentration (MIC) . There were no MIC values obtained from the second screening. This probably due to the insufficient of the active component in bacteria crude extract used for the assay. For the antibiofilm activities, bacteria SC2, SC3, SC4, SC5, SC6, SC7, SC8 and SCIO showed antibiofilm activities with IC50 in range between 36 µI to 70µ1. All the bacteria were identified via I 6S rRNA and only 5 bacteria that showed clear band. They were bacteria SC2, SC3, SC4, SC5 and SC6; and were identified as Bacillus cereus strain CAB 1-1 with 99% similarity, B. cereus strain ROKl with 99% similarity, Bacillus baekryungensis strain HNS89 with 99% similarity, B.cereus strain VCRC B540 with 100% similarity and B.cereus strain VN2 with 99% similarity, accordingly .