title: Genetic characterization indicates that a specific subpopulation of Pseudomonas aeruginosa is associated with keratitis infections.
abstract: Pseudomonas aeruginosa is a common opportunistic bacterial pathogen that causes a variety of infections in humans. Populations of P. aeruginosa are dominated by common clones that can be isolated from diverse clinical and environmental sources. To determine whether specific clones are associated with corneal infection, we used a portable genotyping microarray system to analyze a set of 63 P. aeruginosa isolates from patients with corneal ulcers (keratitis). We then used population analysis to compare the keratitis isolates to a wider collection of P. aeruginosa from various nonocular sources. We identified various markers in a subpopulation of P. aeruginosa associated with keratitis that were in strong disequilibrium with the wider P. aeruginosa population, including oriC, exoU, katN, unmodified flagellin, and the carriage of common genomic islands. The genome sequencing of a keratitis isolate (39016; representing the dominant serotype O11), which was associated with a prolonged clinical healing time, revealed several genomic islands and prophages within the accessory genome. The PCR amplification screening of all 63 keratitis isolates, however, provided little evidence for the shared carriage of specific prophages or genomic islands between serotypes. P. aeruginosa twitching motility, due to type IV pili, is implicated in corneal virulence. We demonstrated that 46% of the O11 keratitis isolates, including 39016, carry a distinctive pilA, encoding the pilin of type IV pili. Thus, the keratitis isolates were associated with specific characteristics, indicating that a subpopulation of P. aeruginosa is adapted to cause corneal infection.
authors.affiliation: Institute of Infection and Global Health, University of Liverpool, Duncan Building, Daulby Street, Liverpool, L69 3GA, United Kingdom.
authors.forename: Rosalind M K
authors.initials: RM
authors.lastname: Stewart
authors.forename: Lutz
authors.initials: L
authors.lastname: Wiehlmann
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Ashelford
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: Preston
authors.forename: Eliane
authors.initials: E
authors.lastname: Frimmersdorf
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Campbell
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Neal
authors.forename: Neil
authors.initials: N
authors.lastname: Hall
authors.forename: Stephen
authors.initials: S
authors.lastname: Tuft
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kaye
authors.forename: Craig
authors.initials: C
authors.lastname: Winstanley
mesh_terms: D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D016680:Genome, Bacterial; D044404:Genomic Islands; D005838:Genotype; D006801:Humans; D007634:Keratitis / Q000382:microbiology*; D046228:Microarray Analysis; D008969:Molecular Sequence Data; D010802:Phylogeny; D039002:Prophages / Q000235:genetics; D011552:Pseudomonas Infections / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D017422:Sequence Analysis, DNA; D037521:Virulence Factors / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D037521:Virulence Factors