Microbiology

Expanding the Host Range of Bacteria

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Science  22 Dec 2000:
Vol. 290, Issue 5500, pp. 2215
DOI: 10.1126/science.290.5500.2215b

Bacterial pathogens can exhibit extraordinary abilities to manipulate their target hosts, for instance by injecting molecules that promote greater binding and uptake of the bacterial invader. The hosts, on the other hand, are equally capable of developing resistance mechanisms that can diminish the virulence or infectivity. Understanding this arms race and exploiting it therapeutically would be accelerated if both organisms were amenable to genetic approaches, which could lead to the identification of mutants and molecules that mediate attack and defense.

Aballay et al. have extended their earlier work in establishing the nematode Caenorhabditis elegans as a host for bacterial infection. Previously, they had shown that a strain of Pseudomonas aeruginosa, which is a human pathogen, could infect C. elegans fatally; now they describe results showing that several strains of Salmonella typhimurium can also infect the nematode. Furthermore, S. typhimurium mutants deficient in a signal transduction pathway regulating virulence in vertebrates displayed significantly less potency in killing C. elegans, hinting at the potential for using the nematode, whose genome and developmental cell lineage are completely known, to dissect virulence mechanisms. Labrousse et al. have confirmed that S. typhimurium can infect C. elegans. They go on to show that mutations that reduce the ability of the bacterium to resist the acid pH of the gut, as expected, attenuate killing efficiency, supporting the proposal that C. elegans can serve as a genetically tractable model host for important human pathogens. — GJC

Curr. Biol.10, 1539 (2000); Curr. Biol.10, 1543 (2000).

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