Adhesion of Pathogenic Bacteria to Polystyrene, Skin and Gut Mucus of Gilthead Seabream, Infectious Capacity and Antibiotics Susceptibility

Abstract

Linking proprieties of adhesion, infectious capacities and antibiotic resistance of pathogen bacteria could help to treat fish diseases. Adhesions of ten fish pathogenic bacteria were tested in microtiter plates vacant, coated with skin or gut mucus, fixed with methanol, stained with 2% crystal-violet and revealed by colorimetric method. Infectious capacity was performed by exposing gilthead seabream fibroblast cell line (SAF-1) to 10 7-10 8 CFUmL-1 of pathogen bacteria. Cell viability was measured 3h, 9h and 20 hours post-infection. The sensitivity to antibiotics was executed by disk diffusion. Data showed that all the bacteria tested adhere to polystyrene. For skin mucus, Vibrio harveyi, Vibrio alginolyticus, Halomonas venusta, and Aeromonas bivalvium were moderately adherent. Dietzia maris was strongly adherent. For gut mucus, 60% of tested bacteria were weakly adherent and 40% were non adherent. For infection, D. maris, V. harveyi and A. bivalvium decreased the cells viability to 89% after only 3h. After 20h, the viability percentage ranged between 1% and 32%. All isolates presented resistance to 1000 mg ml-1 of sulphonamide, 60% were resistant to sulfonamide and penicillin G. Present findings could be relevant in fish aquaculture and underscore the importance of the linkage between adhesion, infectious capacity, and antibiotic susceptibility of pathogen bacteria to avoid fish diseases.

Characterization of Gut Microbiome in the Mud Snail Cipangopaludina cathayensis in Response to High-Temperature Stress

“…Halomonas species, commonly found in saline environments, are halotolerant or halophilic [ 78 ] and cause infections in humans [ 79 ]. Halomonas strains are also considered to be pathogenic in fish [ 80 , 81 ]. Indeed, Halomonas are found to be elevated in the intestine of zebrafish ( Danio rerio ) after pathogen invasion [ 80 ] or exposure to environmental stress (e.g., Microcystis aeruginosa and phthalate esters), inducing intestinal innate immune responses [ 80 ], which results in intestinal injury [ 82 ].…”