Dissemination of Multidrug-Resistant Proteus mirabilis Clones Carrying a Novel Integron-Borne bla_IMP-1 in a Tertiary...

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• The emergence of multidrug-resistant bacteria, particularly Proteus mirabilis, is a growing global health concern.
• Carbapenemase-producing Enterobacteriaceae (CPE) present a critical challenge due to limited treatment options.
• Integrons and plasmids are key mobile genetic elements facilitating the spread of antibiotic resistance genes.

Purpose of the Study:

• To characterize multidrug-resistant Proteus mirabilis clones harboring a novel class 1 integron.
• To investigate the genetic environment of the blaIMP-1 gene within these resistant clones.
• To identify the co-occurrence of other resistance genes on mobile genetic elements.

Main Methods:

• Whole-genome sequencing of Proteus mirabilis isolates.
• Plasmid analysis and characterization.
• Integron and gene cassette analysis.

Main Results:

• Identification of multidrug-resistant Proteus mirabilis clones.
• Characterization of a novel class 1 integron, In1359, carrying the blaIMP-1 gene.
• The integron was located on a large conjugative plasmid that also harbored the blaCTX-M-2 gene.
• The identified clones exhibited intrinsic resistance to polymyxins and tigecycline.

Conclusions:

• The findings highlight the emergence of Proteus mirabilis clones with a concerning resistance profile.
• The co-location of blaIMP-1 and blaCTX-M-2 on a conjugative plasmid facilitates the rapid dissemination of carbapenem and extended-spectrum beta-lactamase resistance.
• These multidrug-resistant strains represent a serious challenge for clinical management and infection control strategies.