Characterization of VIM-4 Producing Clinical Pseudomonas aeruginosa Isolates from Western Algeria: Sequence Type and...

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Genetics

Background:

• Pseudomonas aeruginosa is a major cause of hospital-acquired infections, leading to significant morbidity and mortality.
• Carbapenem resistance in P. aeruginosa is a growing global health concern, necessitating the characterization of resistance mechanisms.

Purpose of the Study:

• To characterize carbapenem resistance mechanisms in Pseudomonas aeruginosa isolates from clinical specimens at the University Hospital of Oran, Algeria.
• To identify specific carbapenemase genes and analyze their genetic context and the clonal relatedness of resistant isolates.

Main Methods:

• Identification of 214 P. aeruginosa isolates using MALDI-TOF MS.
• Antibiotic susceptibility testing via disc diffusion.
• Detection of carbapenemase genes using GeneXpert and multiplex PCR.
• Multilocus Sequence Typing (MLST) for clonal relatedness and phylogenetic analysis.
• Whole-genome sequencing to analyze the flanking regions of the blaVIM-4 gene.

Main Results:

• Eleven isolates (5.39%) exhibited resistance to carbapenems.
• Six isolates (2.94%) harbored the blaVIM-4 gene, carried on a novel class 1 integron with a unique gene cassette arrangement.
• MLST identified seven distinct sequence types (STs), including two novel STs (ST3349, ST3350) and five previously described STs.

Conclusions:

• This study reports the presence of P. aeruginosa isolates producing the VIM-4 carbapenemase in an Algerian hospital setting.
• The blaVIM-4 gene is associated with a class 1 integron containing a new arrangement of gene cassettes, indicating potential for further dissemination.
• Understanding these resistance mechanisms and genetic elements is crucial for developing effective infection control strategies against multidrug-resistant P. aeruginosa.