Trends and implications of antimicrobial resistance in Pseudomonas aeruginosa: Insights from a 19-year study in Zhejiang Province.

This study aimed to elucidate the resistance trends of P. aeruginosa isolates from 2005 to 2023 in Zhejiang Province, emphasizing the impact of Coronavirus disease 2019 (COVID-19) on antimicrobial resistance patterns and clinical management. We retrospectively analyzed 7326 P. aeruginosa isolates collected from diverse clinical sources in a tertiary hospital in Zhejiang Province from 2005 to 2023. Identification and antibiotic susceptibility testing of each isolate were performed using the VITEK-32 automated system and the disk diffusion method, following Clinical and Laboratory Standards Institute guidelines. We assessed resistance patterns for key antibiotic classes relevant to P. aeruginosa treatment, including carbapenems, β-lactams, aminoglycosides, and quinolones. Statistical analyses, including trend evaluations and resistance determinant assessments, were conducted in R software (version 4.2.2), with visualizations generated through ggplot2 to illustrate resistance trends over time. This study focused on key anti-pseudomonal agents including carbapenems (imipenem and meropenem), β-lactams (piperacillin), and quinolones (ciprofloxacin and levofloxacin). We observed a progressive increase in resistance to imipenem from 6.8% in 2005 to 48.2% in 2023 and meropenem from 25.4% to 44.2% over the same period. Conversely, resistance rates to aminoglycosides declined, with gentamicin resistance dropping from 22.0% in 2005 to 5.0% in 2019. Cephalosporins exhibited variable trends, with cefepime resistance peaking at 40.4% in 2013 before declining to 12.1% in 2023. The findings indicated a progressive increase in resistance rates for these antibiotics, with notable peaks coinciding with changes in clinical practices and the COVID-19 pandemic. The analysis demonstrated that shifts in prescription habits, particularly during the COVID-19 pandemic, influenced resistance patterns, underscoring the need for context-specific antimicrobial stewardship strategies. This study identifies significant, evolving resistance patterns in P. aeruginosa over a 19-year period, with marked increases in resistance to critical antibiotics, including carbapenems (imipenem, meropenem), quinolones (levofloxacin, ciprofloxacin), and certain β-lactams (piperacillin). These findings underscore an urgent need for dynamic, tailored infection control measures, emphasizing the importance of robust antibiotic stewardship programs, localized treatment guidelines, and proactive monitoring of resistance trends. Implementing these strategies is essential to effectively counter the challenges posed by multi-drug resistant P. aeruginosa, improve patient outcomes, and sustain the efficacy of vital antibiotic therapies.