Unveiling a new sequence type in high-risk clonal complexes of virulent carbapenem-resistant Pseudomonas aeruginosa carrying blaKPC−2, blaNDM and blaoxa−48

Brazil is a country with an approximate 50% prevalence rate of carbapenem-resistant Pseudomonas aeruginosa (CR-PA). Therefore, monitoring the spread of high-risk clones from complex genotypes of CR-PA isolates is crucial for developing effective strategies to control antimicrobial resistance. In the present study, we aimed to evaluate the dissemination of high-risk clones P. aeruginosa carrying blaKPC-2 in Brazil. In this study, 87 CR-PA isolates were analyzed for virulence (exoU, exoT, exoS, and exoY) and resistance (blaKPC, blaOXA-48, blaPDC, blaNDM, qnrA, and qnrB) markers, detected by PCR and further assessed by RT-qPCR for mexA, mexB, mexE, mexX, blaPDC, oprD, and ampC genes. Clonal relatedness of the isolates was evaluated using multilocus sequence typing (MLST) and Pulsed-Field Gel Electrophoresis. Most isolates were obtained from tracheal secretions (65%). Among the resistance genes evaluated, the prevalent was blaPDC-5 (88%). Additionally, these strains were found carrying important genes, including blaKPC-2 (12%) and blaOXA-48 (4%). No overexpression of efflux pump genes or the blaPDC and ampC genes was observed compared to the control strain (PAO1). Similarly, there was no reduction in oprD gene expression. The MLST analysis revealed that all evaluated strains belonged to novel sequence types (STs). These STs were associated with five different clonal complexes: ST5037, ST5040, ST5043 (CC244), ST5038 (CC155), ST5039 (CC235), ST5041 (CC277), ST5042 (CC639), and ST5044 (CC27). Eight new STs were identified in KPC-P. aeruginosa in Brazil. This finding suggests the need for consistent monitoring of KPC-producing P. aeruginosa to control the spread of high-risk clones in hospital settings.