title: Enhanced in vivo fitness of carbapenem-resistant oprD mutants of Pseudomonas aeruginosa revealed through high-throughput sequencing.
abstract: An important question regarding the biologic implications of antibiotic-resistant microbes is how resistance impacts the organism's overall fitness and virulence. Currently it is generally thought that antibiotic resistance carries a fitness cost and reduces virulence. For the human pathogen Pseudomonas aeruginosa, treatment with carbapenem antibiotics is a mainstay of therapy that can lead to the emergence of resistance, often through the loss of the carbapenem entry channel OprD. Transposon insertion-site sequencing was used to analyze the fitness of 300,000 mutants of P. aeruginosa strain PA14 in a mouse model for gut colonization and systemic dissemination after induction of neutropenia. Transposon insertions in the oprD gene led not only to carbapenem resistance but also to a dramatic increase in mucosal colonization and dissemination to the spleen. These findings were confirmed in vivo with different oprD mutants of PA14 as well as with related pairs of carbapenem-susceptible and -resistant clinical isolates. Compared with OprD(+) strains, those lacking OprD were more resistant to killing by acidic pH or normal human serum and had increased cytotoxicity against murine macrophages. RNA-sequencing analysis revealed that an oprD mutant showed dramatic changes in the transcription of genes that may contribute to the various phenotypic changes observed. The association between carbapenem resistance and enhanced survival of P. aeruginosa in infected murine hosts suggests that either drug resistance or host colonization can cause the emergence of more pathogenic, drug-resistant P. aeruginosa clones in a single genetic event.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115.
authors.forename: David
authors.initials: D
authors.lastname: Skurnik
authors.forename: Damien
authors.initials: D
authors.lastname: Roux
authors.forename: Vincent
authors.initials: V
authors.lastname: Cattoir
authors.forename: Olga
authors.initials: O
authors.lastname: Danilchanka
authors.forename: Xi
authors.initials: X
authors.lastname: Lu
authors.forename: Deborah R
authors.initials: DR
authors.lastname: Yoder-Himes
authors.forename: Kook
authors.initials: K
authors.lastname: Han
authors.forename: Thomas
authors.initials: T
authors.lastname: Guillard
authors.forename: Deming
authors.initials: D
authors.lastname: Jiang
authors.forename: Charlotte
authors.initials: C
authors.lastname: Gaultier
authors.forename: François
authors.initials: F
authors.lastname: Guerin
authors.forename: Hugues
authors.initials: H
authors.lastname: Aschard
authors.forename: Roland
authors.initials: R
authors.lastname: Leclercq
authors.forename: John J
authors.initials: JJ
authors.lastname: Mekalanos
authors.forename: Stephen
authors.initials: S
authors.lastname: Lory
authors.forename: Gerald B
authors.initials: GB
authors.lastname: Pier
mesh_terms: D000818:Animals; D015780:Carbapenems / Q000494:pharmacology*; D004195:Disease Models, Animal; D024881:Drug Resistance, Bacterial / Q000187:drug effects / Q000235:genetics*; D005260:Female; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008264:Macrophages / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D008297:Male; D051379:Mice; D009154:Mutation; D018272:Porins / Q000096:biosynthesis / Q000235:genetics; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity
chemical_list: D015780:Carbapenems; D018272:Porins; C077157:OprD protein, Pseudomonas aeruginosa