[Screening of Molluscacidal Microorganisms against Oncomelania hupensis and Their Effect]

Fifteen soil samples were collected from Oncomelania hupensis culture pond in Miluo Schistosomiasis Control and Prevention Base, Hunan Province. Four strains of bacteria were identified to have molluscacidal effects, numbered as B8, B27, B36 and B59. Compared with the fermentation broth groups and bacteria suspension groups, the fermentation supernatant groups of the four strains showed the strongest molluscacidal effect. The fermentation supernatant of B59 strain showed the best molluscacidal effect, with snail mortalit of 73.3% and 96.7% at 48 h and 72 h of treatment, respectively. SDS-PAGE revealed no proteins in fermentation supernatant, fermentation broth and bacteria suspension of B59 strain. Molecular phylogenetic analysis based on ITS sequence showed that the ITS sequence of strain B59 (accession No. KP146144) was 100% homologous to that of the same fragment of Bacillus cereus (accession No. CP001746).