Work

Two-round point-prevalence study unveils shared blaVIM-2 integrons and spread of a blaIMP-15-encoding plasmid among carbapenem-resistant non-aeruginosa Pseudomonas species in the wet hospital environment

Year: 2026

Type: article

Abstract: Background Wet environmental niches in hospitals may act as reservoirs for carbapenem-resistant Pseudomonas species, posing a risk for horizontal transfer and spread of carbapenemase genes. Aim To determine the presence of carbapenem-resistant non- aeruginosa Pseudomonas spp. in the wet hospital environment in a non-outbreak setting and to characterize the genetic context and spread of carbapenemase genes. Methods A two-round point-prevalence study was conducted in sink and shower drains of the Erasmus MC (Rotterdam, The Netherlands) in 2022 and 2023. Carbapenem-resistant non- aeruginosa Pseudomonas isolates were screened for carbapenemase activity and genes, followed by sequencing of carbapenemase gene-positive isolates. Findings A total of 747 drains were screened, with 98.8% ( N = 738) sampled twice. Carbapenem-resistant strains were detected in 27 out of 744 (3.6%) and 48 out of 741 drains (6.5%) during sampling rounds 1 and 2, respectively, with significantly more contaminated shower than sink drains in round 2 ( P = 0.017). Eight isolates contained a carbapenemase gene, involving bla IMP ( N = 3) and bla VIM ( N = 5), all detected during round 2. An identical bla IMP-15 -encoding plasmid was found in one Pseudomonas arcuscaelestis and two Pseudomonas monteilii , isolated from shower drains in three wards. Five isolates of a novel Pseudomonas species shared an identical bla VIM-2 -containing integron, located on the chromosome. Conclusion Carbapenem-resistant non- aeruginosa Pseudomonas spp. were present in ∼5% of drains. Evidence of horizontal transfer of a bla IMP-15 -encoding plasmid and its spread between wards was found, indicating that these isolates generate a reservoir in drains from which carbapenemase genes can spread through hospital plumbing and reappear in other patient rooms.

Source: Journal of Hospital Infection

DOI: 10.1016/j.jhin.2026.01.003