The Genetic and Phenotypic Diversity of Bacillus spp. from the Mariculture System in China and Their Potential Function against Pathogenic Vibrio

Abstract

Bacillus spp. could be one of the most suitable substitutes for the control and prevention of aquatic diseases. The occurrence of species population, antimicrobial character, and virulence diversity in Bacillus spp. recovered from the mariculture system in China between 2009 and 2021 were investigated, screening for probiotic Bacillus strains with good biological safety that can inhibit Vibrio parahaemolyticus, V. alginolyticus, V. harveyi, V. owensii, V. campbellii. The results showed that 116 Bacillus isolates were divided into 24 species, and the top three species were B. subtilis (37/116), B. velezensis (28/116), and B. amyloliquefaciens (10/116). Among the 116 Bacillus isolates, 32.8% were effective against V. parahaemolyticus, 30.1% for V. alginolyticus, 60.3% for V. harveyi, 69.8% for V. owensii and 74.1% for V. campbellii. More than 62% of Bacillus isolates were susceptible to florfenicol, doxycycline and tetracycline, etc., and 26/116 Bacillus isolates were found to be multiple-antibiotic-resistant (MAR), with MARI values ranging from 0 to 0.06. Eighteen kinds of antibiotic resistance genes were tested; only tetB, blaTEM, and blaZ were detected. And 9 isolates in 2 Bacillus species were excluded by 6/10 kinds of Bacillus-related toxin gene (hblA, hblC, nheB, nheC, entFM, cykK). Bio-safety testing indicated that three kinds of probiotics were good probiotic candidates to prevent Vibriosis. These results provide comprehensive genetic diversity, potential risks, and probiotic characteristics of Bacillus in the mariculture system in China, and provide basic support for green and healthy development of aquatic industry.

Whole Genome Sequencing Reveals Antimicrobial Resistance and Virulence Genes of Both Pathogenic and Non-Pathogenic B. cereus Group Isolates from Foodstuffs in Thailand

“…The isolates that carried the tet(45) gene exhibited a susceptible phenotype to tetracycline. It has been reported that Bacillus isolates showed an antibiotic phenotype that was sensitive to tetracycline while the tetB detection rate was 100% [ 52 ]. This might be due to the presence of varied antimicrobial resistance mechanisms and many genetic factors required for the resistance phenotypes [ 53 ].…”

Role of Bacilli in phytohormone production in rice and grain under different doses of vegetative and generative fertilizer

“…All these toxin genes are well-known as a result of being studied and characterized and have been used to identify the toxin potential of Bacillus species (Lindbäck and Granum, 2015). Despite being mainly reported in widely recognized as 'not-safe' species of Bacillus cereus, several species of Bacillus have also been reported to have these genes (From et al, 2005;Yu et al, 2023). Owing to the diversity of genomic structure between Bacillus species and strains, the presence of one gene may existent in one species and be non-existent in another or even between strains within the same species (Rossi et al, 2018;de Magalhães, 2019;Zhang et al, 2022) with the possible presence of multiple toxin-encoding genes in a Bacillus strain (Jeżewska-Frąckowiak et al, 2017).…”