2004, Number 1
Vet Mex 2004; 35 (1)
Anatibiotic resistance and presence of plasmids in: Aeromonas hydrophila, Vibrio fluvialis, and Vibrio furnissii isolated from Carassius auratus auratus
Negrete RP, Romero JJ, Arredondo FJL
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ABSTRACTWe isolated and identified 70 bacterial strains from the ornate fish species Carassius auratus, in specimens with signs of infection. The isolated and identified bacterial species, Aeromonas hydrophila, Vibrio fluvialis, and Vibrio furnissii, have been reported to cause diarrhea in humans, and the first two are considered very aggressive pathogens in Cyprinus carpio cultures. For this reason, antibiotics to avoid and control the presence of these bacteria have been inadequately used and abused. The uncontrolled use of antibiotics has given rise to the presence of an R-plasmid in bacteria, as a response to the environmental stress represented by these chemical compounds. When R-plasmid carrying bacteria are transmitted directly to humans, be it by direct contact with the host during handling in culture, as a pet, in consumption, or by a conjunction of all these factors, the problem exceeds aquaculture and becomes a public health issue.
All the studied strains presented antibiotic resistance. We recorded resistance to more than one antibiotic, and up to seven in some cases. Furthermore, 100% of the strains carried plasmids resistant to antibiotics with molecular weights ranging from 25.7kb to 6.6 kb. The Aeromonas hydrophila strains presented resistance to the following antibiotics: cephalothin (CF), tetracycline (T), nitrofurantoin (NF), ampicillin (AMP), carbenicillin (CB), and kanamicyn (K). The molecular weights of the plasmids found ranged from 25.7 to 6.6 kb, 24% of Aeromonas hydrophila carried plasmids of 14.2 kb and 21% of 22.5 kb. Plasmids of 15 to 6.9 kb were extracted from Vibrio fluvialis strains, 58% were of 15 kb and were resistant to CF, AMP, T, NF, CB. Vibrio furnissii carrried plasmids ranging from 15 to 6.6 kb, 46% these strains were of 14.2 kb and presented resistance to CF, AMP, T, NF, CB, and K. The results were the same independent of the origin of the samples, be it water, food or an organism.
None of the plasmids were able to transfer to Escherichia coli and no incompatibility group could be determined.