Pathogenic Vibrio spp. identified for white syndrome coral disease in Tioman Island Marine Park, Malaysia

Aims@#Coral diseases have emerged over the last several decades, causing a loss of live coral cover in the Caribbean and Indo-Pacific reefs. Hence, microbiological and disease cultural techniques are commonly used to investigate their causative microbial agents. This is the first study to identify the potential of pathogenic Vibrio spp. isolated from apparently white syndrome (WS) coral disease in Tioman Island Marine Park using biochemical and molecular techniques. @*Methodology and results@#The Vibrio colonies were isolated from 108 samples of WS infected corals (Acropora cytherea and Montipora aequituberculata) including seawater, sediment and algae found adjacent to infected coral colonies. A total of one hundred representative Vibrio isolates were characterized and most of them (n=50) were identified as V. vulnificus, V. alginolyticus and Photobacterium damselae following biochemical analysis. The molecular analysis revealed six Vibrio spp. (V. coralliilyticus, V. hepatarius, V. brasiliensis, V. tubiashi, V. campbellii, V. ishigakensis) and one Photobacterium rosenbergii. Vibrio coralliilyticus isolated from all infected coral samples may be highly responsible for the sign of WS disease.@*Conclusion, significance and impact of study@#The findings of this study provide baseline data and information on potential coral pathogens identified in the coastal waters of Tioman Island. Etiological disease study is suggested to validate their severity and virulence factors in the future.

In vitro antimicrobial activity of mangrove plant Sonneratia alba

Objective:To investigate the antimicrobial property of mangrove plant Sonneratia alba (S. alba). Methods: The antimicrobial activity was evaluated using disc diffusion and microdilution methods against six microorganisms. Soxhlet apparatus was used for extraction with a series of solvents, n-hexane, ethyl acetate and methanol in sequence of increasing polarity. Results:Methanol extract appeared to be the most effective extract while n-hexane extract showed no activity. The antimicrobial activities were observed against the gram positive bacteria Staphylococcus aureus (S. aureus) and Bacillus cereus (B. cereus), the gram negative Escherichia coli (E. coli) and the yeast Cryptococcus neoformans. Pseudomonas aeruginosa and Candida albicans appeared to be not sensitive to the concentrations tested since no inhibition zone was observed. E. coli (17.5 mm) appeared to be the most sensitive strain followed by S. aureus (12.5 mm) and B. cereus (12.5 mm). Conclusions:From this study, it can be concluded that S. alba exhibits antimicrobial activities against certain microorganisms.

Antimicrobial activity of mangrove plant (Lumnitzera littorea)

OBJECTIVE@#To investigate the antimicrobial activities of n-hexane, ethyl acetate and methanol extracts of the leaves of Lumnitzera littorea (L. littorea) against six human pathogenic microbes.@*METHODS@#The antimicrobial activity was evaluated using disc diffusion and microdilution methods.@*RESULTS@#The antimicrobial activities of the crude extracts were increased with increasing the concentration. It is clear that n-hexane extract was the most effective extract. Additionally, Gram positive Bacillus cereus (B. cereus) appear to be the most sensitive strain while Pseudomonas aeruginosa (P. aeruginosa) and the yeast strains (Candida albicans (C. albicans) and Cryptococcus neoformans (C. neoformans)) appear to be resistance to the tested concentrations since no inhibition zone was observed. The inhibition of microbial growth at concentration as low as 0.04 mg/mL indicated the potent antimicrobial activity of L. littorea extracts.@*CONCLUSIONS@#The obtained results are considered sufficient for further study to isolate the compounds responsible for the activity and suggesting the possibility of finding potent antibacterial agents from L. littorea extracts.