1. PLoS One. 2018 Sep 13;13(9):e0204167. doi: 10.1371/journal.pone.0204167.
eCollection 2018.

Great phenotypic and genetic variation among successive chronic Pseudomonas
aeruginosa from a cystic fibrosis patient.

Lozano C(1), Azcona-Gutiérrez JM(2), Van Bambeke F(3), Sáenz Y(1).

Author information: 
(1)Area de Microbiología Molecular, Centro de Investigación Biomédica de La Rioja
(CIBIR), Logroño, Spain.
(2)Departamento de Diagnóstico Biomédico, Laboratorio de Microbiología, Hospital 
San Pedro, Logroño, Spain.
(3)Pharmacologie Cellulaire et Moléculaire, Louvain Drug Research Institute,
Université Catholique de Louvain, Brussels, Belgium.

BACKGROUND/OBJECTIVES: Different adapted Pseudomonas aeruginosa morphotypes are
found during chronic infections. Relevant biological determinants in P.
aeruginosa successively isolated from a cystic fibrosis (CF) patient were
analyzed in this work to gain insight into P. aeruginosa heterogeneity during
chronic infection.
METHODS: Seventeen P. aeruginosa isolates collected from a patient over a 3 year 
period were included, 5 small colony variants (SCV) and 12 mucoids. The following
analyses were performed: Pulsed-Field-Gel-Electrophoresis (PFGE)/Multilocus-
sequence-typing (MLST)/serotype, antimicrobial susceptibility, growth curves,
capacity to form biofilm, pigment production, elastase activity, motility;
presence/expression of virulence/quorum sensing genes, and identification of
resistance mechanisms.
RESULTS: All isolates had closely related PFGE patterns and belonged to ST412.
Important phenotypic and genotypic differences were found. SCVs were more
resistant to antimicrobials than mucoid isolates. AmpC hyperproduction and efflux
pump activity were detected. Seven isolates contained two integrons and nine
isolates only one integron. All SCVs showed the same OprD profile, while three
different profiles were identified among mucoids. No amino acid changes were
found in MutL and MutS. All isolates were slow-growing, generally produced high
biofilm, had reduced their toxin expression and their quorum sensing, and showed 
low motility. Nevertheless, statistically significant differences were found
among SCV and mucoid isolates. SCVs grew faster, presented higher biofilm
formation and flicA expression; but produced less pyorubin and pyocyanin, showed 
lower elastase activity and rhlR, algD, and lasB expression than mucoid isolates.
CONCLUSION: These results help to understand the molecular behavior of chronic P.
aeruginosa isolates in CF patients.

DOI: 10.1371/journal.pone.0204167 
PMID: 30212579 

Conflict of interest statement: The authors have declared that no competing
interests exist.