Resistance to β-lactam antibiotics in Aeromonas hydrophila isolated from rainbow trout (Onchorhynchus mykiss)

Authors

  • Maria José Saavedra Department of Veterinary Sciences, CECAV-University of Trás-os- Montes e Alto Douro, Portugal
  • Sandra Guedes-Novais Department of Veterinary Sciences, CECAV-University of Trás-os- Montes e Alto Douro, Portugal
  • Anabela Alves Department of Veterinary Sciences, CECAV-University of Trás-os- Montes e Alto Douro, Portugal
  • Paulo Rema Department of Animal Production, University of Trás-os-Montes e Alto Douro and CIMAR, University of Porto, Portugal
  • Marta Tacão Department of Biology, Center for Cell Biology, University of Aveiro, Portugal
  • António Correia Department of Biology, Center for Cell Biology, University of Aveiro, Portugal
  • Antonio Martínez-Murcia Molecular Diagnostics Center (Biomolecular Technologies, S.L.); and University Miguel Hernández, Orihuela, Alicante, Spain

Keywords:

Aeromonas hydrophila, antibiotic resistance in fish, rainbow trout (Oncorhynchus mykiss)

Abstract

Bacterial infections caused by members of the genus Aeromonas, with a relatively high antibiotic resistance, are among the most common and troublesome diseases of fish raised in ponds with recirculation systems. In this study, carried out at an experimental aquaculture station in northern Portugal, 51 strains identified as belonging to the genus Aeromonas were isolated from 20 rainbow trout (Oncorhynchus mykiss) skin and kidney samples, as well as from raceway water samples. Macro- and microscopic examination of the fish tissues revealed lesions or cellular alterations in skin and kidney that seemed to correlate with the presence of those isolates. The sensitivity of all isolated strains to different groups of β-lactam antibiotics (penicillins, cephalosporins, monobactams and carbapenems) was evaluated using the disc diffusion method. The highest rates of resistance were to amoxicillin, carbenicillin and ticarcillin. Unexpected resistance to imipenem, an antibiotic of clinical usage, was also detected, which suggests that resistance may have been transferred to the Aeromonas population from the environment. [Int Microbiol 2004; 7(3):207–211]

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Published

2010-02-28

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Section

Research Articles