Differential interactions within the Caenorhabditis elegans-Pseudomonas aeruginosa pathogenesis model.
A pathogenesis model based on the interaction between Caenorhabditis elegans and bacterial opportunistic pathogens has recently been developed. In the case of Pseudomonas aeruginosa, the model is based on three different modes of nematode killing (fast killing, slow killing and lethal paralysis) by virulent bacteria that has been incubated in different nutrient media. Using parametric statistics and Probit analysis, we test the reliability of the three different killing systems with respect to bacterial virulence. To accomplish this, we use three P. aeruginosa strains, each with a different level of virulence and one strain of non-virulent Escherichia coli. Probit function proved to be effective in quantifying the virulence of P. aeruginosa. The results of the killing curve analysis using the Probit function demonstrates that the slow-killing test is the most reliable method for quantifying virulence using the C. elegans model of bacterial pathogenesis. Although the greatest virulence differences are observed after long periods of incubation, the Probit analysis clearly shows that the death kinetics of C. elegans depend on the first hours of nematode/bacteria interaction. In contrast, fast killing seems to be non-specific, at least under our experimental conditions, since the killing rates of virulent P. aeruginosa and non-virulent E. coli strains were indistinguishable.
Ruiz-Díez
Beatriz
B
Departamento de Biodiversidad y Biología Evolutiva, Museo Nacional de Ciencias Naturales, C/Jose Gutierrez Abascal 2, 28006 Madrid, Spain.
Sánchez
Patricia
P
Baquero
Fernando
F
Martínez
José L
JL
Navas
Alfonso
A
D000818:Animals; D017173:Caenorhabditis elegans / Q000469:parasitology*; D018432:Drug Resistance, Multiple; D004926:Escherichia coli; D006801:Humans; D023421:Models, Animal; D009154:Mutation; D009894:Opportunistic Infections / Q000401:mortality*; D011552:Pseudomonas Infections / Q000401:mortality*; D011550:Pseudomonas aeruginosa / Q000235:genetics; D013997:Time Factors; D014774:Virulence