Identification of drug resistance determinants in a clinical isolate of pseudomonas aeruginosa by high-density transposon mutagenesis

Michael S. Sonnabend, Kristina Klein, Sina Beier, Angel Angelov, Robert Kluj, Christoph Mayer, Caspar Groß, Kathrin Hofmeister, Antonia Beuttner, Matthias Willmann, Silke Peter, Philipp Oberhettinger, Annika Schmidt, Ingo B. Autenrieth, Monika Schütz, Erwin Bohn*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    9 Scopus citations


    With the aim to identify potential new targets to restore antimicrobial susceptibility of multidrug-resistant (MDR) Pseudomonas aeruginosa isolates, we generated a high-density transposon (Tn) insertion mutant library in an MDR P. aeruginosa bloodstream isolate (isolate ID40). The depletion of Tn insertion mutants upon exposure to cefepime or meropenem was measured in order to determine the common resistome for these clinically important antipseudomonal β-lactam antibiotics. The approach was validated by clean deletions of genes involved in peptidoglycan synthesis/recycling, such as the genes for the lytic transglycosylase MltG, the murein (Mur) endopeptidase MepM1, the MurNAc/GlcNAc kinase AmgK, and the uncharacterized protein YgfB, all of which were identified in our screen as playing a decisive role in survival after treatment with cefepime or meropenem. We found that the antibiotic resistance of P. aeruginosa can be overcome by targeting usually nonessential genes that turn essential in the presence of therapeutic concentrations of antibiotics. For all validated genes, we demonstrated that their deletion leads to the reduction of ampC expression, resulting in a significant decrease in β-lactamase activity, and consequently, these mutants partly or completely lost resistance against cephalosporins, carbapenems, and acylaminopenicillins. In summary, the determined resistome may comprise promising targets for the development of drugs that may be used to restore sensitivity to existing antibiotics, specifically in MDR strains of P. aeruginosa.

    Original languageEnglish (US)
    Article numbere01771-19
    JournalAntimicrobial Agents and Chemotherapy
    Issue number3
    StatePublished - 2020


    • AmpC β-lactamase
    • Antibiotics
    • Clinical isolate
    • Multidrug resistance
    • Peptidoglycan
    • Peptidoglycan recycling
    • Pseudomonas aeruginosa
    • TraDIS

    ASJC Scopus subject areas

    • Pharmacology
    • Pharmacology (medical)
    • Infectious Diseases


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