Characterization of multi-antibiotic resistant bacteria isolated from ornamental fishes and therapeutic potential of phytochemicals

Abstract

The ornamental fish industry is developing rapidly in the worldwide. However, the ornamental fish also is the source for spreading the pathogens from fish to human. In this study, the biological characteristics of 7 Gram (+) bacteria strains isolated from 4 ornamental fish species in Ho Chi Minh City, including their susceptivity with antibiotics and plant extract substances (phytochemicals) was investigated. The studied result showed that there were 6 out of 7 multi-antibiotic resistant strains, resisted to at least 8/12 antibiotics. For the banned antibiotics, 7 above bacteria strains were susceptible with ciprofloxacin and ofloxaxin, and very few strains were susceptible with ampicillin (4/7), tetracyclin (1/7), and chloramphenicol (0/7). There were 5 out of 6 randomly selected isolates were identified as Enterococcus faecalis by 16S rRNA gene sequencing (> 99,6% of similarity). There were 2 plant extract substances, such as TT1 and TT2, these substances could inhibit 4 bacterial strains isolated from Japanese koi, carp, and oranda goldfish. Particularly, the studied results showed the ornamental fish infected with E. faecalis could be the reason for spreading the antibiotic resistant genes into natural environment and causing the bad effects to the local fish population and human health. The use of phytochemicals replacing antibiotics in prophylaxis and therapy for ornamental fish would be the safe solution. However, mechanisms generating the occurrence of super resistance phenomenon and bacteria inhibition of the phytochemicals need to be further studied.