title: Abundance of the Quorum-Sensing Factor Ax21 in Four Strains of Stenotrophomonas maltophilia Correlates with Mortality Rate in a New Zebrafish Model of Infection.
abstract: Stenotrophomonas maltophilia is a Gram-negative pathogen with emerging nosocomial incidence. Little is known about its pathogenesis and the genomic diversity exhibited by clinical isolates complicates the study of pathogenicity and virulence factors. Here, we present a strategy to identify such factors in new clinical isolates of S. maltophilia, incorporating an adult-zebrafish model of S. maltophilia infection to evaluate relative virulence coupled to 2D difference gel electrophoresis to explore underlying differences in protein expression. In this study we report upon three recent clinical isolates and use the collection strain ATCC13637 as a reference. The adult-zebrafish model shows discrimination capacity, i.e. from very low to very high mortality rates, with clinical symptoms very similar to those observed in natural S. maltophilia infections in fish. Strain virulence correlates with resistance to human serum, in agreement with previous studies in mouse and rat and therefore supporting zebrafish as a replacement model. Despite its clinical origin, the collection strain ATCC13637 showed obvious signs of attenuation in zebrafish, with null mortality. Multilocus-sequence-typing analysis revealed that the most virulent strains, UV74 and M30, exhibit the strongest genetic similitude. Differential proteomic analysis led to the identification of 38 proteins with significantly different abundance in the three clinical strains relative to the reference strain. Orthologs of several of these proteins have been already reported to have a role in pathogenesis, virulence or resistance mechanisms thus supporting our strategy. Proof of concept is further provided by protein Ax21, whose abundance is shown here to be directly proportional to mortality in the zebrafish infection model. Indeed, recent studies have demonstrated that this protein is a quorum-sensing-related virulence factor.
authors.affiliation: Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, Barcelona, Spain.
authors.forename: Mario
authors.initials: M
authors.lastname: Ferrer-Navarro
authors.forename: Raquel
authors.initials: R
authors.lastname: Planell
authors.forename: Daniel
authors.initials: D
authors.lastname: Yero
authors.forename: Elías
authors.initials: E
authors.lastname: Mongiardini
authors.forename: Gerard
authors.initials: G
authors.lastname: Torrent
authors.forename: Pol
authors.initials: P
authors.lastname: Huedo
authors.forename: Paula
authors.initials: P
authors.lastname: Martínez
authors.forename: Nerea
authors.initials: N
authors.lastname: Roher
authors.forename: Simon
authors.initials: S
authors.lastname: Mackenzie
authors.forename: Isidre
authors.initials: I
authors.lastname: Gibert
authors.forename: Xavier
authors.initials: X
authors.lastname: Daura
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D004195:Disease Models, Animal; D024881:Drug Resistance, Bacterial; D016905:Gram-Negative Bacterial Infections / Q000401:mortality*; D006367:HeLa Cells; D006801:Humans; D010641:Phenotype; D040901:Proteomics; D053038:Quorum Sensing; D020615:Stenotrophomonas maltophilia / Q000166:cytology / Q000378:metabolism* / Q000472:pathogenicity / Q000502:physiology; D014774:Virulence; D015027:Zebrafish / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins