Antibacterial activity in secondary metabolite extracts of heterotrophic bacteria against Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas aeruginosa

Abstract

Background: Disease causing bacteria such as Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas aeruginosa present a problem for fish farming. Treatment to remove them are generally carried out using antibiotics which have side effects on fish, the environment and humans. However, the use of antibacterial compounds derived from heterotrophic bacteria serve as a good alternative for antibiotics. Therefore, this study aimed to explore antibacterial activity in the secondary metabolite extracts of heterotrophic bacteria against Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas aeruginosa. Methods: Heterotrophic bacteria namely Bacillus sp. JS04 MT102913.1, Bacillus toyonensis JS08 MT102920.1, Bacillus cereus JS10 MT102922.1, Bacillus sp. JS11 MT102923.1, Pseudoalteromonas sp. JS19 MT102924.1, Bacillus cereus JS22 MT102926.1, and Bacillus sp. strain JS25 MT102927.1 were used in this study. The sequences of these bacteria have been deposited and are available from NCBI GenBank. Each heterotrophic bacterium was cultured on 6L nutrient broth for 8 days, and extracts produced using ethyl acetate to obtain their secondary metabolites. These extracts were tested for their phytochemical contents using FT-IR and also tested for their inhibitory property in pathogenic bacteria by agar diffusion method. Results: Phytochemical test results showed that the seven heterotrophic bacterial isolates produced terpenoid compounds. Based on the inhibitory test, the secondary metabolite extracts from Bacillus sp strain JS04 had the highest inhibitory effect on the growth of pathogenic bacteria namely, V. alginolyticus (17.5 mm), A. hydrophila (16.8 mm), and P. aeruginosa (17.3 mm). Conclusion: It was concluded that the secondary metabolite extracts of heterotrophic bacteria inhibit the growth of V. alginolyticus, A. hydrophila, and P. aeruginosa.

Molecular Identification and Characterization of Probiotic Bacillus Species with the Ability to Control Vibrio spp. in Wild Fish Intestines and Sponges from the Vietnam Sea

“…To explain antimicrobial spectra, all of the 16 Vi+ were checked for antimicrobial biosynthetic gene clusters relating to the production of non-ribosomal peptides, polyketide type I (PKS-I), and polyketide type II (PKS-II). These antimicrobial substances have shown activity against a wide range of other bacteria including Vibrio species [ 6 , 13 , 14 ]. A PCR reaction was performed to amplify conserved gene regions within the genes coding non-ribosomal peptide synthetase (NRPS), polyketide type I synthetase (PKS-I), and polyketide synthetase (PKS-II) enzymes.…”

Screening and Molecular Identification of Bacteria from the Midgut of Amphimallon solstitiale Larvae Exhibiting Antagonistic Activity against Bacterial Symbionts of Entomopathogenic Nematodes

“…Similarly, Lopes et al [ 49 ] sequenced the whole B. toyonensis BAC3151 genome and found that it had a higher frequency of putative bacteriocin gene clusters than that of Bacillus species used traditionally for production of antimicrobials. In turn, secondary metabolite extracts produced by B. toyonensis collected from sea waters inhibited the growth of Vibrio alginolyticus , Aeromonas hydrophila , and Pseudomonas aeruginosa [ 50 ].…”

Screening of sponge-associated bacteria to control vibriosis in vannamei shrimp (Litopenaeus vannamei)

“…Possibly one or several combinations of these mechanisms was responsible for these results. Several studies showed that B. cereus is capable of inhibiting V. alginolyticus (Feliatra et al 2021;Setiaji et al 2020), by producing secondary metabolites compounds i.e., alkaloid, flavonoid, and saponin (Feliatra et al 2021). These secondary metabolites compounds are capable to disrupt the peptidoglycan, one of the major constituents of bacterial cell wall, that causes lysis in cells (Feliatra et al 2021).…”