Photobacterium damselae Case in Farmed Sea Bream and Sea Bass: Molecular Identification and Antibiotic Susceptibility

In the current study, gilthead sea bream (n = 100) and European sea bass (n = 100), with suspected infection by P. damselae, which showed skin lesions, were sampled under aquaculture conditions. P. damselae was diagnosed by the BD Phoenix rapid diagnosis system, and its subspecies were identified by polymerase chain reaction. Initially, BD Phoenix identified 26 Photobacterium damselae isolates from all tissue samples. Also, as to polymerase chain reaction analysis, 8 isolates from 26 identified isolates showed positive results for the 16S rRNA, ureC, and CPS genes and were identified as P. damselae subsp. damselae. On the other hand, isolates (n = 18) with 16S rRNA and CPS gene-positive and ureC gene-negative results were defined as P. damselae subsp. piscicida. Antibiotic tests showed that P. damselae subsp. damselae isolates were susceptible to amoxicillin-clavulanic acid, ciprofloxacin, cefotaxime, and ampicillin. Conversely, P. damselae subsp. piscicida isolates were sensitive to ciprofloxacin and gentamicin.