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Updated: Jun 3, 2026
Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
Published on: March 3, 2023
Epidemiology and genetics of VIM-type metallo-β-lactamases in Gram-negative bacilli
1Department of Microbiology & Immunology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, Japan. whzhao@med.showa-u.ac.jp
Abstract:
Metallo-β-lactamases (MBLs) are a rapidly evolving group of β-lactamases, which hydrolyze most β-lactams including the carbapenems. Of the known MBLs, VIMs are one of the most common families, with 27 variants detected in at least 23 species of Gram-negative bacilli from more than 40 countries/regions. The amino acid similarities of VIM variants range from 72.9 to 99.6% with 1-72 different residues. Most of the bla (VIM)s are harbored by a class 1 integron, a genetic platform able to acquire and express gene cassettes. The integrons are usually embedded in transposons and, in turn, accommodated on plasmids, making them highly mobile. Integrons display considerable diversity, with at least 110 different structures associated with the gain and spread of the bla (VIM)s. In most instances, the bla (VIM)s co-exist with one or more other resistance genes. The processes for the identification of bacteria harboring bla (VIM)s are also discussed in this article.
Insights
Metallo-β-lactamases (MBLs), particularly VIM variants, are spreading rapidly among Gram-negative bacteria. These enzymes confer resistance to critical antibiotics like carbapenems, often facilitated by mobile genetic elements.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Metallo-β-lactamases (MBLs) are a significant class of enzymes conferring resistance to β-lactam antibiotics, including carbapenems.
- VIM-type MBLs represent a common and evolving family, with numerous variants identified globally in Gram-negative bacteria.
Purpose of the Study:
- To review the diversity and spread of VIM-type metallo-β-lactamases.
- To discuss the genetic platforms, such as integrons and plasmids, that facilitate the dissemination of bla (VIM) genes.
- To highlight the co-occurrence of bla (VIM) with other antibiotic resistance genes.
Main Methods:
- Literature review of studies on metallo-β-lactamases, focusing on VIM variants.
- Analysis of genetic structures (integrons, transposons, plasmids) associated with bla (VIM) genes.
- Examination of bacterial species, geographic distribution, and amino acid variations of VIM variants.
Main Results:
- 27 VIM variants have been detected in at least 23 Gram-negative bacterial species across over 40 countries.
- Amino acid similarities among VIM variants range from 72.9% to 99.6%.
- bla (VIM) genes are predominantly located on class 1 integrons, often within mobile genetic elements like transposons and plasmids, promoting horizontal gene transfer.
Conclusions:
- The genetic mobility of bla (VIM) genes, facilitated by diverse integron structures and plasmids, drives their widespread dissemination.
- The co-existence of bla (VIM) with other resistance genes exacerbates the challenge of treating Gram-negative bacterial infections.
- Understanding these genetic mechanisms is crucial for developing strategies to combat MBL-mediated antibiotic resistance.
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