TY - JOUR

T1 - Macrolide therapy in Pseudomonas aeruginosa infections causes uL4 ribosomal protein mutations leading to high-level resistance

AU - Goltermann, Lise

AU - Andersen, Kasper Langebjerg

AU - Johansen, Helle Krogh

AU - Molin, Søren

AU - La Rosa, Ruggero

N1 - Publisher Copyright: © 2022 The Author(s)

PY - 2022

Y1 - 2022

N2 - Objectives: Pseudomonas aeruginosa colonizes the cystic fibrosis (CF) airways causing chronic bacterial lung infections. CF patients are routinely treated with macrolides, however, P. aeruginosa is considered insusceptible as consequence of inadequate susceptibility testing leaving resistance mechanism completely overlooked. Here, we investigated a new mechanism of macrolide resistance caused by ribosomal protein mutations. Methods: Investigating a longitudinal collection of 529 isolates from CF patients and analysing 5758 protein sequences from different sources, mutations in P. aeruginosa's ribosomal proteins connected to macrolide resistance were identified. Using a modified susceptibility testing protocol, isolates harbouring a mutated uL4 ribosomal protein were tested for resistance against macrolide antibiotics and macrolide-induced quorum sensing modulation. Proteome and ribosome profiling were applied to assess the impact of the mutations on the bacterial physiology. Results: Five uL4 mutations were identified in isolates from different CF patients. Most mapped to the conserved loop region of uL4 and resulted in increased macrolide tolerance (>10-fold relative to wt strains). Greater concentrations (>10-fold) of macrolide antibiotic were needed to inhibit the growth, reduce swimming motility, and induce redox sensitivity of the uL4 mutants. 16 proteins involved in ribosome adaptation displayed altered expression possibly to compensate for the uL4 mutations, which changed the ribosome stoichiometry without negatively affecting bacterial physiology. Conclusions: Macrolide antibiotics should, therefore, be considered as active antimicrobial agents against P. aeruginosa and resistance development should be contemplated when patients are treated with prolonged courses of macrolides. Importantly, improved macrolide susceptibility testing is necessary for the detection of resistant bacteria.

AB - Objectives: Pseudomonas aeruginosa colonizes the cystic fibrosis (CF) airways causing chronic bacterial lung infections. CF patients are routinely treated with macrolides, however, P. aeruginosa is considered insusceptible as consequence of inadequate susceptibility testing leaving resistance mechanism completely overlooked. Here, we investigated a new mechanism of macrolide resistance caused by ribosomal protein mutations. Methods: Investigating a longitudinal collection of 529 isolates from CF patients and analysing 5758 protein sequences from different sources, mutations in P. aeruginosa's ribosomal proteins connected to macrolide resistance were identified. Using a modified susceptibility testing protocol, isolates harbouring a mutated uL4 ribosomal protein were tested for resistance against macrolide antibiotics and macrolide-induced quorum sensing modulation. Proteome and ribosome profiling were applied to assess the impact of the mutations on the bacterial physiology. Results: Five uL4 mutations were identified in isolates from different CF patients. Most mapped to the conserved loop region of uL4 and resulted in increased macrolide tolerance (>10-fold relative to wt strains). Greater concentrations (>10-fold) of macrolide antibiotic were needed to inhibit the growth, reduce swimming motility, and induce redox sensitivity of the uL4 mutants. 16 proteins involved in ribosome adaptation displayed altered expression possibly to compensate for the uL4 mutations, which changed the ribosome stoichiometry without negatively affecting bacterial physiology. Conclusions: Macrolide antibiotics should, therefore, be considered as active antimicrobial agents against P. aeruginosa and resistance development should be contemplated when patients are treated with prolonged courses of macrolides. Importantly, improved macrolide susceptibility testing is necessary for the detection of resistant bacteria.

KW - Antibiotic resistance

KW - Antibiotic susceptibility testing

KW - Cystic fibrosis

KW - Macrolide antibiotics

KW - Pseudomonas aeruginosa

KW - Ribosome

U2 - 10.1016/j.cmi.2022.08.003

DO - 10.1016/j.cmi.2022.08.003

M3 - Journal article

C2 - 35988850

AN - SCOPUS:85138592024

VL - 28

SP - 1594

EP - 1601

JO - Clinical Microbiology and Infection

JF - Clinical Microbiology and Infection

SN - 1198-743X

IS - 12

ER -