title: Pseudomonas aeruginosa displays an epidemic population structure.
abstract: Bacteria can have population structures ranging from the fully sexual to the highly clonal. Despite numerous studies, the population structure of Pseudomonas aeruginosa is still somewhat contentious. We used a polyphasic approach in order to shed new light on this issue. A data set consisting of three outer membrane (lipo)protein gene sequences (oprI, oprL and oprD), a DNA-based fingerprint (amplified fragment length polymorphism), serotype and pyoverdine type of 73 P. aeruginosa clinical and environmental isolates, collected across the world, was analysed using biological data analysis software. We observed a clear mosaicism in the results, non-congruence between results of different typing methods and a microscale mosaic structure in the oprD gene. Hence, in this network, we also observed some clonal complexes characterized by an almost identical data set. The most recent clones exhibited serotypes O1, 6, 11 and 12. No obvious correlation was observed between these dominant clones and habitat or, with the exception of some recent clones, geographical origin. Our results are consistent with, and even clarify, some seemingly contradictory results in earlier epidemiological studies. Therefore, we suggest an epidemic population structure for P. aeruginosa, comparable with that of Neisseria meningitidis, a superficially clonal structure with frequent recombinations, in which occasionally highly successful epidemic clones arise.
authors.affiliation: Laboratory of Microbial Interactions, Department of Immunology, Parasitology, and Ultrastructure, Flanders Interuniversity Institute of Biotechnology, Brussels Free University, Paardenstraat 65, B-1640 Sint-Genesius-Rode, Belgium.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Pirnay
authors.forename: Daniel
authors.initials: D
authors.lastname: De Vos
authors.forename: Christel
authors.initials: C
authors.lastname: Cochez
authors.forename: Florence
authors.initials: F
authors.lastname: Bilocq
authors.forename: Alain
authors.initials: A
authors.lastname: Vanderkelen
authors.forename: Martin
authors.initials: M
authors.lastname: Zizi
authors.forename: Bart
authors.initials: B
authors.lastname: Ghysels
authors.forename: Pierre
authors.initials: P
authors.lastname: Cornelis
mesh_terms: D000483:Alleles; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000032:analysis* / Q000235:genetics; D030561:Databases, Nucleic Acid; D005798:Genes, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D011552:Pseudomonas Infections / Q000453:epidemiology* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000235:genetics*; D012703:Serotyping
chemical_list: D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial