Effects of cecropin peptides on bacteria pathogenic to fish

Abstract

The antibacterial effects of synthetic cecropin B and cecropin P1 were tested against the fish‐pathogenic bacteria Vibrio anguillarum, Vibrio salmonicida, Aeromonas salmonicida, Edwardsiella ictaluri and Yersinia ruckeri. Both cecropins were active against all bacteria tested, but the effect was strongly influenced by the growth media used. In brain heart infusion medium, the minimum inhibitory concentrations of cecropin B ranged from 0.3 to 1.3 μm and from 0.3 to 1.0 μm for cecropin P1, except for E. ictaluri, which was noticeably less sensitive to cecropin P1 (61 μm). The present authors have compared the bactericidal activity of these two peptides, showing that the killing rate for the selected bacteria was higher for cecropin B than for cecropin P1. V. anguillarum was the most sensitive to the cecropins, and in the present study, no colony forming units were detected after 4 and 8 min of treatment with cecropin B and P1, respectively. Electron microscopy was performed to document the effect of cecropin on the bacterial surface.

Antibacterial activity in four marine crustacean decapods

“…Salt was removed from the aqueous phase by solid phase extraction. The fractions (maximum 100 ml) were separately loaded on to 35 cc Sep-Pak C 18 Vac cartridges (Water Associates, MA, U.S.A.) equilibrated in acidified water (0·05% TFA). After washing with acidified water, three stepwise elutions were performed with 10, 40 and 80% (v/v) ACN in acidified water, respectively.…”

Effects of Cecropin Peptides on Aquatic Animal Pathogens and Shrimp Hemocytes.

“…Brugia pahangi, a human pathogenic nematoda. However, only one paper has been documented in rela tion to the antimicrobial activities of cecropin peptides on fish pathogens including four bacterial species (Kjuul et al, 1999). Neither the antimicrobial activity of the pep tides on the pathogens of the other aquatic organisms such as bivalves and crustaceans nor the cytotoxic effect has been assessed for therapeutic purpose.…”

“…These results indicate that cecropin peptides provide antimicro bial activity with a broad spectrum, although the growth inhibitory activity was not found against Edwardsiella tarda, Flavobacterium columnare, Flexibacter maritimus and V. vulnificus biogroup II (Table 1). Kjuul et al (1999) reported that Edwardsiella ictaluri was less sensi tive to cecropin, which could be attributed to the struc ture differences in the bacterial cell wall. Zaldivar (1985) found that the outer membrane of F. columnare was surrounded by galactosamine-rich secretion in TEM preparations treated with ruthenium red.…”

“…In NaCl susceptibility test (Fig.1), the killing activity of cecropin performed well in a low concentration (0.1-0.3 M NaCl) but was decreased in a high concentration (0.5 M NaCl). Kjuul et al (1999) reported that the antibacterial effect of cecropin peptides was strongly reduced with increased concentration of NaCl in the growth medium. Kjuul et al (1999) and Yomogida et al (1997) …”

“…Kjuul et al (1999) reported that the antibacterial effect of cecropin peptides was strongly reduced with increased concentration of NaCl in the growth medium. Kjuul et al (1999) and Yomogida et al (1997) …”