Penghambatan Virulensi AHPND Vibrio parahaemolyticus melalui Mekanisme Anti Quorum Sensing Bacillus spp.

Abstract

Acute hepatopancreatic necrosis disease (AHPND) merupakan penyakit pada udang vaname (Penaeus vannamei) yang dapat disebabkan oleh Vibrio parahaemolyticus. Molekul N-acyl homoserine lactone berperan dalam ekspresi toksin penyebab AHPND. Anti quorum sensing (AQS) dapat dijadikan sebagai metode terapi alternatif pengobatan AHPND. Beberapa jenis Bacillus diketahui memiliki kemampuan mendegradasi AHL melalui enzim AQS berupa AHL laktonase. Penelitian ini bertujuan menganalisis penghambatan virulensi AHPND Vibrio parahaemolyticus melalui mekanisme AQS Bacillus spp. Metode penelitian terdiri atas persiapan sampel, uji antagonisme dengan V.parahaemolyticus, uji hemolysis, uji patogenitas pada larva udang vaname, uji penghambatan virulensi secara in vivo. Hasil uji antagonisme Bacillus spp. dengan V. parahaemolyticus mengindikasikan B4 bekerja dengan mekanisme AQS dalam penghambatan patogenitas V. parahaemolyticus, sedangkan pada B1 diduga berjalan dua proses yang bersamaan yaitu antimikrob dan AQS. Berdasarkan pengujian hemolisis, diketahui pada bakteri B4 terjadi beta hemolisis, sedangkan pada bakteri B1 tidak terjadi hemolisis. Uji patogenitas pada udang larva udang vaname menunjukkan nilai survival rate yang tidak berbeda signifikan dengan kontrol negatif. Berdasarkan uji penghambatan virulensi in vivo, kedua isolat Bacillus tidak cukup dapat menghambat virulensi V. parahaemolyticus.

Acute hepatopancreatic necrosis disease (AHPND) affects vannamei shrimp (Penaeus vannamei). This disease can cause by the Vibrio parahaemolyticus bacterium. The expression of the AHPND toxin is influenced by N-acyl homoserine lactone (AHL). Anti-quorum sensing (AQS) may be a potential alternative treatment for AHPND. Several Bacillus bacteria are known to be able to degrade AHL through the AQS enzyme, AHL-lactonase. This study aims to analyze the virulence inhibition of AHPND Vibrio parahaemolyticus through the AQS mechanism of Bacillus spp. The methods used in this study are sample preparation, antagonism test with V. parahaemolyticus, hemolysis test, pathogenicity test on vannamei shrimp larvae, and in vivo virulence inhibition test. Antagonism testing indicated that Bacillus B4 possesses an AQS mechanism that restrains the pathogenicity of V. parahaemolyticus. Meanwhile, Bacillus B1 exhibits both antimicrobial and AQS activity. B4 bacterium displays beta hemolysis activity. In contrast, the B1 bacterium lacks hemolytic activity. Pathogenicity testing revealed no significant difference in survival rate values compared to the negative control. However, the in vivo virulence inhibition test indicated that the two Bacillus isolates are not sufficiently capable of inhibiting the virulence of AHPND V. parahaemolyticus.