Epidemiology, Evolution of Antimicrobial Profile and Genomic Fingerprints of Pseudomonas aeruginosa before and during COVID-19: Transition from Resistance to Susceptibility

Background: The purpose of the study was to describe the epidemiological implication of Pseudomonas aeruginosa between 2017-2022 in a tertiary hospital from Romania, including the molecular fingerprinting of similar phenotypic strains (multidrug-resistant isolates), which would have an important health impact. The study also describes the resistance profile of P. aeruginosa before and during COVID-19, which might bring new information regarding the management of antibiotic treatments. Materials and methods: Information regarding wards, specimen types, species, and antibiotic resistance profile of 1994 strains of Pseudomonas spp. Isolated over a period of 6 years in Mures Clinical County Hospital, Romania, was collected from the WHONET database. From 50 multidrug-resistant isolates, molecular fingerprinting was performed by Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) to prove the potential clonal distribution. Results: A number of 1994 Pseudomonas spp. were isolated between 2017-2022, from which P. aeruginosa was the most frequent species, 97.39% (n = 1942). P. aeruginosa was most frequently isolated in 2017 (n = 538), with the dermatology department as the main source, mainly from pus secretion. A drop in the harvesting rate was noted in 2020 due to COVID-19 restrictions. Regarding the resistance profile, there are a few modifications. The susceptibility of P. aeruginosa to carbapenems, piperacillin-tazobactam, and amikacin suffered alterations before and during COVID-19. The molecular fingerprinting showed three P. aeruginosa clusters, including strains with 80-99% similarity.