Antimicrobial resistance and in vitro gene transfer in bacteria isolated from the ulcers of EUS-affected fish in India.
OBJECTIVE
The occurrence of drug resistance and plasmid-mediated transferability was investigated in 15 Aeromonas isolates collected from the ulcers of epizootic ulcerative syndrome (EUS)-affected fishes Katla (Catla catla), Mrigel (Cirrhinus mrigala) and Punti (Puntius sp.).


RESULTS
Disc diffusion assay showed that all the strains were resistant to ampicillin and sensitive to streptomycin. Of the 15 isolates examined, 93.3% isolates were resistant to erythromycin, sulfadiazine and novobiocin, while 66% were resistant to rifampin and 20% to chloramphenicol. All isolates harboured plasmids with sizes ranging from 64 to 23 kbp with a 23-kbp plasmid in common. Plasmids from 11 Aeromonas strains were transferred to Escherichia coli DH5alpha recipient strain along with the transfer of ampicillin, erythromycin and chloramphenicol resistance determinants with frequencies ranging from 7.0 x 10(-6) to 1.8 x 10(-5) transconjugants per recipient cell.


CONCLUSIONS
The resistance to ampicillin, erythromycin, sulfadiazine, novobiocin and chloramphenicol is prevalent among the bacteria isolated from EUS-affected fish, and resistant determinants of some of these antibiotics have been transferred to the bacteria of other origin.


CONCLUSIONS
The emergence of antibiotic resistance bacteria and gene transfer in vitro suggests that antibiotics should be used more cautiously to treat Aeromonas infections in aquaculture.
Das
A
A
Department of Zoology, North Bengal University, Siliguri, India.
Saha
D
D
Pal
J
J
D000333:Aeromonas / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003227:Conjugation, Genetic; D024881:Drug Resistance, Bacterial; D005393:Fish Diseases / Q000382:microbiology*; D005399:Fishes; D022761:Gene Transfer, Horizontal; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology / Q000662:veterinary*; D010957:Plasmids / Q000235:genetics; D014456:Ulcer / Q000382:microbiology*
D000900:Anti-Bacterial Agents