Vibrio cholerae (V. cholerae) is an etiological cause of cholera and has been implicated in several epidemics. Exploration of the antimicrobial signatures of culinary spices has become an important industrial tool to suppress the growth of foodborne bacterial pathogens including Vibrio spp. The antibiofilm and antimotility activities of some selected natural antimicrobial agents were then evaluated. All the extracts showed vibriostatic activities with minimum inhibitory concentration (MIC) ranging from 0.1% to 0.4%. Cinnamon and black pepper demonstrated significant biofilm inhibition activity from 94.77% to 99.77% when administered at 100% MIC. Black pepper extract also demonstrated the highest biofilm inhibition activity against the established biofilms of V. cholerae O1 and O139. Cinnamon, calabash nutmeg, and black pepper significantly inhibited swimming and swarming motility by 85.51% to 94.87%. Sub-MICs (50% and 75%) of some extracts were also effective as an antibiofilm and antimotility agent against the tested strains. The findings of our study suggest the potential application of natural antimicrobial agents such as spices in food to inhibit biofilm formation and motility, which consequently mitigate the virulence and persistence of the pathogen in the food supply chain.

Bacterial reverse transcriptase coding gene (RT) is essential for the production of a small satellite DNA‐RNA complex called multicopy single‐stranded DNA (msDNA). In this study, we found a novel retron, retron‐Vmi1 (Vm85) from Vibrio mimicus. The retron is comprised of the msr‐msd region, orf323, and the ret gene, a genetic organization similar to Salmonella's retron‐Sen2 (St85). The protein sequence of the RNA‐directed DNA polymerase (RT‐Vmi1) is highly homologous to the RTs of Vibrio metoecus, Vibrio parahaemolyticus, and Vibrio vulnificus. Phylogenetic and protein sequence similarity analysis of retron‐Vmi1 ORF323 and RT revealed a close relatedness to retron‐Sen2. We found that retron‐Vmi1 was inserted in the dusA gene, similar to the insertion of the retron‐Vpa1 (Vp96) of V. parahaemolyticus AQ3354, suggesting that retrons can be transferred via the tRNA gene. These results are the first convincing evidence that retron is moving across species. The neighboring genes of retron‐Vmi1 shared high homology with the genetic environment of V. parahaemolyticus and V. vulnificus retrons. We also found two junction points within the retron‐Vmi1 and the dusA gene suggesting that retron‐Vmi1 was inserted into this site in a two‐step manner.

The combination of plant extracts with mild heat treatment is a promising strategy for obtaining microbiologically and chemically safe food products. In this study, we evaluated the antimicrobial activity of ethanolic clove extract against Escherichia coli O157: H7 in nutrient broth, buffer, and tomato juice. Clove extract at 0.4% concentration showed significant E. coli O157: H7 population reduction in all media tested. E. coli O157: H7 was most sensitive to the ethanolic clove extract in nutrient-deficient media but demonstrated relative resistance in nutrient-rich media and tomato juice. Moreover, we evaluated the potential of clove extract as a preservative in tomato juice stored at cold storage temperatures of 4 °C and 15 °C. The clove extract exhibited stronger inhibitory effects against the pathogen in tomato juice stored at 15 °C than at 4 °C. Additionally, we assessed the antimicrobial efficacy of clove extract in combination with mild heat treatment against E. coli O157: H7 in tomato juice. The combined treatment of 0.05% clove extract with mild heat at 60 °C for 30 min achieved a 5-log reduction in the E. coli population in tomato juice. Our findings present a potential hurdle technology against E. coli O157: H7 in tomato juice processing by employing a combination of naturally sourced antimicrobial agents from clove and mild heat treatment. This approach can be effectively adopted by large-scale industries and small-scale local juice vendors to ensure the safety of tomato juice products.

Vibrio cholerae is a gram‐negative bacterium found in water, particularly in brackish and estuarine environments, and causes cholera—an acute disease transmitted through contaminated food or water. Biofilm formation in V. cholerae enhances its resistance to antimicrobial agents and protection against host immune responses. Natural plant extracts have gained attention for their potential antibiofilm properties against human pathogens such as V. cholerae . This study evaluates the antibacterial and antibiofilm activities of bluestem ( Andropogon spp.) extracts against pathogenic V. cholerae strains using antibacterial assays, biofilm inhibition and eradication assays, and gene expression analysis. Two extracts, denoted as EAV1 and EAV2, primarily composed of two flavonoid C‐glycosides species, demonstrated significant bactericidal effects on V. cholerae . Sub‐MIC levels of the extracts also inhibited the growth of biofilms. Gene expression analysis revealed downregulation of genes encoding biofilm transcriptional regulators, Vibrio polysaccharide, and biofilm matrix proteins upon EAV treatment. Results indicate a potential quorum‐quenching activity by targeting the transcription of biofilm regulators and biofilm matrix genes. These findings suggest that Andropogon spp. extract is a promising antibacterial and antibiofilm agent against V. cholerae , highlighting the potential of plant species with invasive tendencies as sources of antibacterial and antibiofilm compounds against clinically important pathogens.

Escherichia coli poses global health risks, affecting human, animal, and environmental systems. To investigate the determinants underpinning its environmental persistence, we conducted an integrated genotypic and phenotypic analysis of 365 E . coli isolates recovered from treated sewage in Hiroshima, Japan. Isolates were confirmed by uidA ‐PCR and screened for virulence, antimicrobial resistance (AMR), phylogroup, and siderophore‐associated genes using multiplex PCR. Phenotypic assays assessed biofilm formation on microtiter plates and motility on soft agar. Among the isolates, 13.7% carried one or more virulence genes, with astA being the most prevalent (70.0%), followed by eaeA (8.0%), bfpA (6.0%), and the aggR ‐ astA combination (4.0%). AMR genes were detected in 50.0% of isolates, predominantly bla _TEM . The major phylogroups were D (36.0%) and B1 (24.0%). All isolates carried entA–F and tonB , while fecA and chuA were the predominant accessory iron‐acquisition genes (52.0%). Phenotypic analysis showed that 92.0% of isolates formed biofilms and 100.0% were motile. aggR ‐positive isolates exhibited the highest biofilm production, whereas astA ‐, bfpA ‐, and eaeA ‐positive isolates demonstrated greater motility than ipaH ‐positive isolates. Principal component analysis indicated that biofilm formation was associated with aggR , whereas motility showed an opposing trend. Together, these traits contribute to the environmental persistence of E . coli in treated sewage.