title: Genotypic and phenotypic relatedness of Pseudomonas aeruginosa isolates among the major cystic fibrosis patient cohort in Italy.
abstract: Pseudomonas aeruginosa is the predominant pathogen associated with the decline of pulmonary function in cystic fibrosis (CF) patients. Both environment-to-host acquisition and patient-to-patient transmission have been described for P. aeruginosa infection. Epidemic clones and bacterial phenotypic adaptation to the CF lung have been recognised as independent risk factors for disease progression. So far, there is no established link between genotypic prevalence and phenotypic traits. Here, we look at the major CF patient cohort in Italy to identify shared P. aeruginosa clones and associated common phenotypic traits.
  
  
  
  A comprehensive analysis of P. aeruginosa genotypes to determine the presence of high-risk shared clones and their association to specific phenotypic traits has been performed in a major Italian CF centre. Pulsed-field gel electrophoresis (PFGE) of P. aeruginosa isolates from 338 CF subjects identified 43 profiles shared by two or more patients and 214 profiles exclusive to individual patients. There was no evidence of a P. aeruginosa outbreak, but four most prevalent pulsotypes were detected. Common phenotypic traits were recorded intra-pulsotypes, but we detected heterogeneity inter-pulsotypes. Two of the four major pulsotypes included P. aeruginosa isolates with hallmarks of adaptation to the CF airways, including loss of motility, low production of siderophore, pyocyanin and proteases, and antibiotic resistance. One of these pulsotypes grouped a high percentage of hypermutable isolates. No clear correlation between epidemiological and clinical data was found.
  
  
  
  We conclude that CF patients of this cohort shared common pulsotypes, but their phenotypic heterogeneity indicates an absence of specific traits associated to P. aeruginosa genotypic prevalence.
authors.affiliation: Infections and Cystic Fibrosis Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, via Olgettina 58, 20132, Milan, Italy. cigana.cristina@hsr.it.
authors.forename: Cristina
authors.initials: C
authors.lastname: Cigana
authors.affiliation: Cystic Fibrosis Center, Azienda Ospedaliera Universitaria Integrata di Verona, piazzale Stefani 1, 37126, Verona, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Melotti
authors.affiliation: Emerging Bacterial Pathogens Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, via Olgettina 58, 20132, Milan, Italy.
authors.forename: Rossella
authors.initials: R
authors.lastname: Baldan
authors.affiliation: Infections and Cystic Fibrosis Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, via Olgettina 58, 20132, Milan, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Pedretti
authors.affiliation: Cystic Fibrosis Center, Azienda Ospedaliera Universitaria Integrata di Verona, piazzale Stefani 1, 37126, Verona, Italy.
authors.forename: Emily
authors.initials: E
authors.lastname: Pintani
authors.affiliation: Cystic Fibrosis Center, Azienda Ospedaliera Universitaria Integrata di Verona, piazzale Stefani 1, 37126, Verona, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Iansa
authors.affiliation: Infections and Cystic Fibrosis Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, via Olgettina 58, 20132, Milan, Italy.
authors.forename: Ida
authors.initials: I
authors.lastname: De Fino
authors.affiliation: Microbiology and Virology Unit, Department of Pathology, Azienda Ospedaliera Universitaria Integrata di Verona, piazzale Stefani 1, 37126, Verona, Italy.
authors.forename: Flavio
authors.initials: F
authors.lastname: Favari
authors.affiliation: Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134, Verona, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Bergamini
authors.affiliation: Cystic Fibrosis Center, Azienda Ospedaliera Universitaria Integrata di Verona, piazzale Stefani 1, 37126, Verona, Italy.
authors.forename: Gloria
authors.initials: G
authors.lastname: Tridello
authors.affiliation: Emerging Bacterial Pathogens Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, via Olgettina 58, 20132, Milan, Italy.
authors.forename: Daniela M
authors.initials: DM
authors.lastname: Cirillo
authors.affiliation: Cystic Fibrosis Center, Azienda Ospedaliera Universitaria Integrata di Verona, piazzale Stefani 1, 37126, Verona, Italy.
authors.forename: Baroukh M
authors.initials: BM
authors.lastname: Assael
authors.affiliation: Infections and Cystic Fibrosis Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, via Olgettina 58, 20132, Milan, Italy. bragonzi.alessandra@hsr.it.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bragonzi
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003550:Cystic Fibrosis / Q000453:epidemiology / Q000382:microbiology*; D018450:Disease Progression; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007223:Infant; D007558:Italy / Q000453:epidemiology; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D015995:Prevalence; D011552:Pseudomonas Infections / Q000453:epidemiology / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology*; D012307:Risk Factors; D055815:Young Adult
keywords: Bacterial adaptation; Bacterial genotype; Bacterial phenotype; Cystic fibrosis; Pseudomonas aeruginosa