Isolation and characterisation of Bacillus spp. antagonistic to Vibrio parahaemolyticus for use as probiotics in aquaculture

Abstract

Acute gastroenteritis caused by pathogenic Vibrio parahaemolyticus is one of the major factors affecting the development of aquaculture and the safety of seafood. Using the antagonism of probiotics against pathogens is an alternative strategy to antibiotics and a common trend to control food-borne pathogenic bacteria. In this study, a total of 249 isolates were isolated from four types of seafood (Litopenaeus vannamei, Oratosquilla oratoria, Mactra veneriformis and Portunus trituberculatus) and coastal sediment from Liaodong Bay in the Bohai Sea, China with five different separation agars. The most isolates came from the sample of coastal sediment and on agar of 2216E, which accounted for 36.14 and 54.62 % respectively. Twenty-four among 249 isolates displayed direct antimicrobial activity to V. parahaemolyticus with spot inoculation. Sixteen active isolates were selected for extracellular antimicrobial activity using the Oxford cup method. Only strains of B16 and J7 showed extracellular antimicrobial activity and were identified as Bacillus pumilus and Bacillus mojavensis respectively based on the physiological identification and 16S rRNA sequence analysis. Both of the strains B16 and J7 exhibited extracellular hydrolytic enzyme activity and antagonism against more than one indicator bacteria in vitro, which indicates that the two strains have broad potential application as suitable probiotic candidates in aquaculture while B. mojavensis was first reported to inhibit pathogenic Vibrio spp. in vitro. There is no particular trait as to antagonism of B. pumilus B16 or B. mojavensis J7 to Gram-positive or Gram-negative indicator bacteria.

Bioluminescence Imaging to Track Bacteroides fragilis Inhibition of Vibrio parahaemolyticus Infection in Mice

“…The use of probiotics to treat intestinal infection would eliminate these problems. Most research about the antagonistic effects of other bacterial species on V. parahaemolyticus has focused on applications for aquaculture (Wu et al, 2014; Liu et al, 2015), and most of the strains used cannot be considered probiotics. Studies on the use of probiotics for treating intestinal infection caused by V. parahaemolyticus are rare, and only strains of Lactobacillus have been shown to inhibit V. parahaemolyticus both in vitro and in vivo in mice (Yang et al, 2013).…”

Characterization of a novel marine origin aerobic nitrifying–denitrifying bacterium isolated from shrimp culture ponds

“…Bacillus sp. have been evaluated as probiotics and are widely distributed in the natural environment, including marine environments (Liu et al, ; Nithya, Aravindraja, & Pandian, ). They are widely used in aquaculture to improve the water quality, increase the immunity and promote the growth of the farmed species by influencing the composition of the microbial populations and reducing the number of pathogens in the aquatic environment (Farzanfar, ; Song, An, Fu, & Yang, ).…”

Effects of dietary supplementation of a marine thermotolerant bacterium, Bacillus paralicheniformis SO‐1, on growth performance and immune responses of Nile tilapia, Oreochromis niloticus

“…Computer‐aided database API‐WEB™ V.5.0 software was used for the result interpretation (Khalil et al, ). In addition, 16S rRNA gene sequencing was used to identify the bacterial isolate as described by Liu et al () and similarity search was performed in the GenBank database using the online tool BLAST (http://blast.ncbi.nlm.nih.gov/Blast.cgi).…”