The in vitro susceptibility of Aeromonas salmonicida and other fish- pathogenic bacteria to 29 antimicrobial agents

Citation

Inglis V & Richards R (1991) The in vitro susceptibility of Aeromonas salmonicida and other fish- pathogenic bacteria to 29 antimicrobial agents. Journal of Fish Diseases, 14 (6), pp. 641-650. https://doi.org/10.1111/j.1365-2761.1991.tb00622.x

Abstract
The minimum inhibitory concentrations (MICs) of 29 antimicrobial agents were determined for some representative Aeromonas salmonidda, Yersinia ruckeri and Vibrio isolates. Eleven of them, including three widely used in clinical practice, were further tested against 28-36 recent field isolates of A. salmonidda. The fluoroquinolones were inhibitory at very low concentrations with 50% of A. salmonidda isolates having a MIC of enro-floxacin ≤0·02μg ml-1. The distribution of MICs to the fluoroquinolones and to oxolinic acid were similar indicating possible cross resistance. Amoxycillin, florfenicol, minocycline, rifampicin and the potentiated sulphonamides had a single peak MIC distribution with values of ≤1·25μg ml-1. Minimum inhibitory concentrations of the fluoroquinolones were four or more times greater at 10°C compared with 22°C; this was not so with amoxycillin, florfenicol or the sulphachlorpyridazine-trimethoprim (S-TP) combination. A. salmonicida was rapidly killed at 22°C by the fluoroquinolones and S-TP whereas oxolinic acid and amoxycillin killed within 24h. Florfenicol was bacteriostatic. The therapeutic potential of some of these antibiotics is considered.

Journal
Journal of Fish Diseases: Volume 14, Issue 6

People

Professor Randolph Richards

Emeritus Professor, Institute of Aquaculture