In vitro antimicrobial susceptibilities and production of β-lactamases in marine Vibrio and Photobacterium

Abstract

Four marine strains of Vibrio and Photobacterium were tested for their susceptibilities to 22 antimicrobial agents. All strains were susceptible to chloramphenicol, nalidixic acid, cotrimoxazole, tetracycline, netilmicin and norfloxacin; all were resistant to penicillin and ampicillin, and exhibited β-lactamase activity. However, there were significant differences between strains, especially in their patterns of betalactam and aminoglycosides susceptibility. Vibrio splendidus biovar 1 and Vibrio harveyi have β-lactamases of the 2d group (cloxacillin-hydrolyzing β-lactamases), Photobacterium angustum has β-lactamases of the 2b group (broad-spectrum β-lactamases inhibited by clavulanic acid), and Photobacterium phosphoreum var. K has β-lactamases of the 2c group (carbenicillin-hydrolyzing β-lactamases inhibited by clavulanic acid).