Nationwide genome surveillance of carbapenem-resistantPseudomonas aeruginosain Japan

Abstract

ABSTRACTJapan is a representative country with a low prevalence rate of carbapenem-resistantPseudomonas aeruginosa(CRPA). A comprehensive overview of the genotype and phenotype patterns of CRPA in the Asia-Pacific region is lacking. Herein, we conducted genome sequencing and standardized quantitative antimicrobial susceptibility testing for 382 meropenem-resistant CRPA isolates that were collected from 78 hospitals across Japan from 2019 to 2020. CRPA exhibited susceptibility rates of 52.9%, 26.4%, and 88.0% against piperacillin-tazobactam, ciprofloxacin, and amikacin, respectively, whereas 27.7% of CRPA isolates were classified as difficult-to-treat resistanceP. aeruginosa. Only 4.1% of CRPA isolates carried carbapenemase: GES-5 (2), IMP-1 (5), IMP-10 (4), IMP-7 (3), IMP-34 (1), and IMP-98 (1). Regarding chromosomal mutations, 87.1% of CRPA isolates possessed inactivating or other resistance mutations inoprD, and 28.8% showed mutations in the regulatory genes (mexR, nalC, andnalD) for the MexAB-OprM efflux pump. Additionally, 4.7% of CRPA isolates carried a known resistance mutation in the PBP3-encoding geneftsI. Of the 148 sequence types detected, ST274 (9.7%) was predominant, followed by ST235 (7.6%) and ST253 (4.5%). The findings from this study and other surveillance studies collectively demonstrate that CRPA exhibits marked genetic diversity and that its multidrug resistance in Japan is less perceived than in other regions. This study contributes a valuable dataset that addresses a gap in genotype/phenotype information regarding CRPA in the Asia-Pacific region, where the epidemiological background markedly differs between regions.