Antibiotic resistant Vibrio harveyi isolated from shrimp pond and anti-Vibrio activity of Combretum quadrangulare Kurz. and Mimosa pudica extracts

Aims@#The occurrence of bacterial disease in shrimp ponds is a major problem faced in shrimp farming. Thus, the aims of this study were to isolate and evaluate antibiotic resistant profile of Vibrio harveyi strain isolated from shrimp pond water, as well as to study the potential anti-Vibrio activity of Combretum quadrangulare Kurz. (CQ) and Mimosa pudica (MP) leaves extracts.@*Methodology and results@#Vibrio harveyi WSC103 was isolated from water in white shrimp (Litopenaeus vannamei) culture pond and identified using 16S rRNA gene sequencing analysis. This strain showed characteristics of multidrug-resistant (7 antibiotics). It had become more sensitive to antibiotics (9 out of 10 antibiotics) after plasmid curing. It is showed CQ and MP leaves extracts contain potent bioactive compounds (tannins, flavonoids, steroids, cardiac glycosides and alkaloids) against V. harveyi WSC103. The aqueous, 95% ethanolic and 75% acetone extracts of CQ (MIC value of 3.13-12.50 mg/mL) and MP (MIC value of 3.13-25.00 mg/mL) leaves revealed strong vibriostatic activity, but aqueous and 95% ethanolic extracts in both plants showed vibriocidal activity. The 95% ethanolic extract of both CQ and MP leaves displayed the excellent vibriocidal property with MBC value of 100 mg/mL with zone of inhibition at 11.44 ± 1.01 and 11.78 ± 1.01 mm by agar disc diffusion.@*Conclusion, significance and impact of study@#The isolated Vibrio harveyi WSC103 was successfully characterized as a novel multidrug-resistant strain. The ethanolic C. quadrangulare Kurz. and M. pudica extracts exhibited prominent vibriostatic and vibriocidal capacities. These finding is proven that C. quadrangulare Kurz. and M. pudica extracts would be an alternative anti-Vibrio agent for aquaculture infectious treatment.

Aspergixanthones I⁻K, New Anti-Vibrio Prenylxanthones from the Marine-Derived Fungus Aspergillus sp. ZA-01.

Marine-derived fungi are a rich source of structurally diverse metabolites. Fungi produce an array of compounds when grown under different cultivation conditions. In the present work, different media were used to cultivate the fungus Aspergillus sp. ZA-01, which was previously studied for the production of bioactive compounds, and three new prenylxanthone derivatives, aspergixanthones I⁻K (1⁻3), and four known analogues (4⁻7) were obtained. The absolute configuration of 1 was assigned by ECD experiment and the Mo2(AcO)4 ICD spectrum of its methanolysis derivative (1a). All the compounds (1⁻7) were evaluated for their anti-Vibrio activities. Aspergixanthone I (1) showed the strongest anti-Vibrio activity against Vibrio parahemolyticus (MIC = 1.56 µM), Vibrio anguillarum (MIC = 1.56 µM), and Vibrio alginolyticus (MIC = 3.12 µM).

Mentha spicata Essential Oil: Chemical Composition, Antioxidant and Antibacterial Activities against Planktonic and Biofilm Cultures of Vibrio spp. Strains.

Chemical composition, antioxidant and anti-Vibrio spp. activities of the essential oil isolated from the aerial parts of Mentha spicata L. (spearmint) are investigated in the present study. The effect of the essential oil on Vibrio spp. biofilm inhibition and eradication was tested using the XTT assay. A total of 63 chemical constituents were identified in spearmint oil using GC/MS, constituting 99.9% of the total identified compounds. The main components were carvone (40.8% ± 1.23%) and limonene (20.8% ± 1.12%). The antimicrobial activity against 30 Vibrio spp. strains (16 species) was evaluated by disc diffusion and microdilution assays. All microorganisms were strongly affected, indicating an appreciable antimicrobial potential of the oil. Moreover, the investigated oil exhibited high antioxidant potency, as assessed by four different tests in comparison with BHT. The ability of the oil, belonging to the carvone chemotype, to inhibit or reduce Vibrio spp. biofilm warrants further investigation to explore the use of natural products in antibiofilm adhesion and reinforce the possibility of its use in the pharmaceutical or food industry as a natural antibiotic and seafood preservative against Vibrio contamination.