Co-existence of Plasmid-encoded blaVIM-4 and Chromosomal blaNDM-1 in a Carbapenem-Resistant Pseudomonas guariconensis clinical isolate from Ethiopia: Comparative Genomic and Phylogenetic Analysis

Pseudomonas guariconensis is a rare clinical isolate. This paper reports the first detection of a plasmid harboring carbapenem-resistant P. guariconensis strain, PM99, isolated from a patient admitted at Tikur Anbessa Specialized Hospital in Ethiopia. The isolate was phenotypically susceptible to colistin and resistant to carbapenems. Whole genome sequencing was performed using long read sequencing. The isolate carried a plasmid-encoded blaVIM-4 gene embedded within a class 1 integron, alongside sul1 and qnrVC6 genes. The blaVIM-4 gene was flanked upstream by a DDE-Tn3 family transposase and downstream by IS91 family transposases, forming a putative composite transposon. This plasmid configuration suggests a mobile genetic structure capable of facilitating horizontal gene transfer and contributing to the dissemination of carbapenem resistance. The isolate also carried chromosomal blaNDM-1,blaOXA-10, sul1, aph(3')-VIa, aac(6')-Ib, and ant(3'')-Ia) genes. Pairwise SNP analysis showed that all publicly available P. guariconensis genomes differed from PM99 by > 700 SNPs, suggesting no close genetic relatedness. Although P. guariconensis is a rare clinical isolate, its capacity to harbor resistance determinants in both stable and mobile genetic contexts raises concern about its potential role as a reservoir for antimicrobial resistance. Furthermore, its potential to survive in different environments warrant further genomic monitoring.