Positive correlation between virulence of Pseudomonas aeruginosa mutants in mice and insects

Abstract

Strain PA14, a human clinical isolate of Pseudomonas aeruginosa, is pathogenic in mice and insects (Galleria mellonella). Analysis of 32 different PA14 mutants in these two hosts showed a novel positive correlation in the virulence patterns. Thus, G. mellonella is a good model system for identifying mammalian virulence factors of P. aeruginosa.

FIG. 1

G. mellonella 60 h after infection with a mean of one PA14 bacterium. Dead larvae show increased melanization.

FIG. 2

Time course of PA14 infection in G. mellonella. Twenty-five bacteria per larva were injected at time zero. Each data point represents the mean and standard deviation of bacterial counts from 10 groups of 10 larvae. Larvae died approximately 48 h after injection, when bacterial concentrations reached 10⁹/g.

FIG. 3

Comparison of LD₅₀ in G. mellonella and percent survival of burned mice after infection with 10⁵ P. aeruginosa bacteria. Solid square, PA14; open squares, individual mutants derived from PA14. y = 17.7 · x + 23.7, P < 0.001, R = 0.565.