Luminescence, virulence and quorum sensing signal production by pathogenic Vibrio campbellii and Vibrio harveyi isolates.

AIMS

To study the relationship between luminescence, autoinducer production and virulence of pathogenic vibrios.

METHODS AND RESULTS

Luminescence, quorum sensing signal production and virulence towards brine shrimp nauplii of 13 Vibrio campbellii and Vibrio harveyi strains were studied. Although only two of the tested strains were brightly luminescent, all of them were shown to produce the three different types of quorum sensing signals known to be produced by Vibrio harveyi. Cell-free culture fluids of all strains significantly induced bioluminescence in the cholerae autoinducer 1, autoinducer 2 and harveyi autoinducer 1 reporter strains JAF375, JMH597 and JMH612, respectively. There was no relation between luminescence and signal production and virulence towards brine shrimp.

CONCLUSIONS

There is a large difference between different strains of Vibrio campbellii and Vibrio harveyi with respect to bioluminescence. However, this is not reflected in signal production and virulence towards gnotobiotic brine shrimp. Moreover, there seems to be no relation between quorum sensing signal production and virulence towards brine shrimp.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results presented here indicate that strains that are most brightly luminescent are not necessarily the most virulent ones and that the lower virulence of some of the strains is not due to a lack of autoinducer production.