Table 1.

Role of the three Photobacterium damselae subsp. damselae hemolysins in virulence for mice and fish (turbot).

Strain	Hemolysin(s) produced	Number of dead mice (n = 15)	Number of dead fish (n = 15)
Parental	HlyAch HlyApl Dly	15	15
ΔhlyAch	HlyApl Dly	13	9*
ΔhlyApl	HlyAch Dly	10*	14
Δdly	HlyAch HlyApl	10*	4*
ΔhlyAch ΔhlyApl	Dly	12	5*
ΔhlyAch Δdly	HlyApl	9*	0*
ΔhlyApl Δdly	HlyAch	3*	0*
ΔhlyAch ΔhlyApl Δdly	none	0*	0*

Parental and mutant strains were inoculated in groups of 15 animals, at doses of 2.1 × 10⁶ bacterial cells per mouse and 2.1 × 10⁴ bacterial cells per fish. The number of dead animals out of the total number of inoculated animals (15) is indicated. Asterisks denote that significant differences exist between a given mutant and the parental strain, using U-test (*P < 0.05).