Genetic characteristics of chromosomally integrated carbapenemase gene (bla NDM−1) in isolates of Proteus mirabilis

Abstract

Abstract Objective This study aims to conduct an in-depth genomic analysis of a carbapenem-resistant Proteus mirabilis strain to uncover the distribution and mechanisms of its resistance genes. Methods The research primarily utilized whole-genome sequencing to analyze the genome of the Proteus mirabilis strain. Additionally, antibiotic susceptibility tests were conducted to evaluate the strain’s sensitivity to various antibiotics, and related case information was collected to analyze the clinical distribution characteristics of the resistant strain. Results Study on bacterial strain WF3430 from a tetanus and pneumonia patient reveals resistance to multiple antibiotics due to extensive use. Whole-genome sequencing exposes a 4,045,480 bp chromosome carrying 29 antibiotic resistance genes. Two multidrug-resistant (MDR) gene regions, resembling Tn6577 and Tn6589, were identified (MDR Region 1: 64.83 Kb, MDR Region 2: 85.64 Kbp). These regions, consist of integrative and conjugative elements (ICE) structures, highlight the intricate multidrug resistance in clinical settings. Conclusion This study found that a CR-PMI strain exhibits a unique mechanism for acquiring antimicrobial resistance genes, such as bla NDM−1, located on the chromosome instead of plasmids. According to the results, there is increasing complexity in the mechanisms of horizontal transmission of resistance, necessitating a comprehensive understanding and implementation of targeted control measures in both hospital and community settings.

Keywords

• Proteus mirabilis
• Carbapenem-resistant enterobacteriaceae (CRE)
• bla NDM−1
• Multidrug-resistant (MDR)
• Antibiotic resistance