Purpose: The purpose of this study was to examine the prevalence of four important drug-resistance phenotypes: difficult-to-treat resistance (DTR), fluoroquinolone resistance (FQR), carbapenem resistance (CR), and extended-spectrum cephalosporin resistance (ECR).
Methods: DTR was defined as insensitivity to all the β-lactams and fluoroquinolones tested. We retrospectively analyzed the distribution characteristics of specific drug-resistant phenotypes of the main Gram-negative bacteria causing bloodstream infections (BSIs) in Tongji Hospital (Wuhan, China) between 2013 and 2021: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa , and Acinetobacter baumannii .
Results: FQR was the main antimicrobial resistance phenotype of E. coli , accounting for 59.45% (1117/1879, 95% confidence interval, 57.21%– 61.65%); the detection rates for CR and DTR were low, accounting for 1.86% (35/1879, 1.34%– 2.58%), and 1.81% (34/1879, 1.30%– 2.52%), respectively. However, the detection rates for CR and DTR in K. pneumoniae were 38.83% (497/1280, 36.20%– 41.53%) and 35.94% (460/1280, 33.35%– 38.60%), respectively. In P. aeruginosa , the detection rates of the four drug-resistant phenotypes (DTR, CR, FQR, and ECR) were all < 30%, but conversely, for A. baumannii , the detection rates were all > 80%. The changes in the data from 2013 to 2021 showed upward trends (z > 0) for CR-E. coli , DTR-E. coli , FQR-E. coli , CR-K. pneumoniae , DTR-K. pneumoniae , FQR-K. pneumoniae , and ECR-K. pneumoniae , but downward trends (z < 0) for ECR-E. coli , CR-A. baumannii , DTR-A. baumannii , FQR-A. baumannii , ECR-A. baumannii , CR-P. aeruginosa , DTR-P. aeruginosa , FQR-P. aeruginosa , and ECR-P. aeruginosa .
Conclusion: DTR warrants further attention, especially in in BSI-associated K. pneumoniae and A. baumannii , in which the detection rates were very high. Between 2013 and 2021 in this region, DTR-E. coli and CR-E. coli showed obvious upward trends, whereas DTR-P. aeruginosa and ECR-P. aeruginosa showed obvious downward trends.
Keywords: DTR, CR, ECR, FQR, BSI