Related Experiment Video
Updated: Oct 21, 2025
Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
Published on: March 3, 2023
Antimicrobial susceptibility patterns of respiratory Gram-negative bacterial isolates from COVID-19 patients in
Marina Gysin1, Claudio Tirso Acevedo2, Klara Haldimann1
1Institute of Medical Microbiology, University of Zurich, Gloriastrasse 30, 8006, Zurich, Switzerland.
Background:
Bacterial superinfections associated with COVID-19 are common in ventilated ICU patients and impact morbidity and lethality. However, the contribution of antimicrobial resistance to the manifestation of bacterial infections in these patients has yet to be elucidated.
Methods:
We collected 70 Gram-negative bacterial strains, isolated from the lower respiratory tract of ventilated COVID-19 patients in Zurich, Switzerland between March and May 2020. Species identification was performed using MALDI-TOF; antibiotic susceptibility profiles were determined by EUCAST disk diffusion and CLSI broth microdilution assays. Selected Pseudomonas aeruginosa isolates were analyzed by whole-genome sequencing.
Results:
Pseudomonas aeruginosa (46%) and Enterobacterales (36%) comprised the two largest etiologic groups. Drug resistance in P. aeruginosa isolates was high for piperacillin/tazobactam (65.6%), cefepime (56.3%), ceftazidime (46.9%) and meropenem (50.0%). Enterobacterales isolates showed slightly lower levels of resistance to piperacillin/tazobactam (32%), ceftriaxone (32%), and ceftazidime (36%). All P. aeruginosa isolates and 96% of Enterobacterales isolates were susceptible to aminoglycosides, with apramycin found to provide best-in-class coverage. Genotypic analysis of consecutive P. aeruginosa isolates in one patient revealed a frameshift mutation in the transcriptional regulator nalC that coincided with a phenotypic shift in susceptibility to β-lactams and quinolones.
Conclusions:
Considerable levels of antimicrobial resistance may have contributed to the manifestation of bacterial superinfections in ventilated COVID-19 patients, and may in some cases mandate consecutive adaptation of antibiotic therapy. High susceptibility to amikacin and apramycin suggests that aminoglycosides may remain an effective second-line treatment of ventilator-associated bacterial pneumonia, provided efficacious drug exposure in lungs can be achieved.
Insights
Antimicrobial resistance is a significant factor in bacterial superinfections among ventilated COVID-19 patients. Aminoglycosides like amikacin and apramycin show promise as second-line treatments for ventilator-associated pneumonia.
Area of Science:
- Infectious Diseases
- Microbiology
- Critical Care Medicine
Background:
- Bacterial superinfections are common in ventilated COVID-19 patients, increasing morbidity and mortality.
- The role of antimicrobial resistance in these superinfections remains unclear.
Purpose of the Study:
- To investigate antimicrobial resistance patterns in Gram-negative bacteria from ventilated COVID-19 patients.
- To assess the potential contribution of antimicrobial resistance to bacterial superinfections.
Main Methods:
- Collected 70 Gram-negative bacterial strains from lower respiratory tracts of ventilated COVID-19 patients.
- Identified species using MALDI-TOF and determined antibiotic susceptibility via EUCAST and CLSI methods.
- Performed whole-genome sequencing on selected Pseudomonas aeruginosa isolates.
Main Results:
- Pseudomonas aeruginosa (46%) and Enterobacterales (36%) were the predominant pathogens.
- High resistance rates were observed in P. aeruginosa to piperacillin/tazobactam, cefepime, ceftazidime, and meropenem.
- Most isolates remained susceptible to aminoglycosides, with apramycin showing broad coverage.
Conclusions:
- Significant antimicrobial resistance may contribute to bacterial superinfections in ventilated COVID-19 patients.
- Aminoglycosides (amikacin, apramycin) show potential as second-line therapies for ventilator-associated bacterial pneumonia.
- Treatment adaptation may be necessary due to evolving resistance patterns.
More Related Videos
09:26Antibiotic Efficacy Testing in an Ex vivo Model of Pseudomonas aeruginosa and Staphylococcus aureus Biofilms in the Cystic Fibrosis Lung
Published on: January 22, 2021
07:46Use of Artificial Sputum Medium to Test Antibiotic Efficacy Against Pseudomonas aeruginosa in Conditions More Relevant to the Cystic Fibrosis Lung
Published on: June 5, 2012
