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Published on: January 7, 2019
High-risk KPC-producing Klebsiella pneumoniae lack type I R-M systems
Ying Zhou1, Dongxing Tian1, Yu Tang2
1Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
Abstract:
Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-KP) have disseminated worldwide and are a major threat to public health. The multidrug-resistant (MDR)-phenotype of KPC-KP are commonly associated with the presence of high molecular weight blaKPC plasmids. Restriction-modification (R-M) systems provide bacteria with innate defense against plasmids or other infectious gene elements. As blaKPC plasmids are favored by such MDR K. pneumoniae, it was of interest to examine the co-distribution of R-M and acquired blaKPC plasmids in KPC-KP. A total of 459 clinical K. pneumoniae isolates in China and 217 global whole-genome sequences in GenBank were collected to determine the prevalence of type I R-M systems. The type I R-M systems were scarce in the KPC-positive group and high-risk Klebsiella pneumoniae clonal group 258 (CG258). The polymorphisms of type I R-M observed in K. pneumoniae revealed the ubiquity of their recognition sequences in DNA; therefore, the type I R-M systems could attack most invading DNA elements, such as blaKPC genes. Overall, this work indicated the type I R-M systems may impact the acquisition of blaKPC genes in K. pneumoniae.
Insights
Type I restriction-modification systems are rare in carbapenem-resistant Klebsiella pneumoniae, suggesting they may limit the acquisition of blaKPC genes. This finding impacts understanding of antimicrobial resistance spread.
Area of Science:
- Microbiology
- Genetics
- Public Health
Background:
- Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-KP) are a global health threat.
- Multidrug resistance in KPC-KP is often linked to blaKPC plasmids.
- Restriction-modification (R-M) systems are bacterial defense mechanisms against foreign DNA.
Purpose of the Study:
- To investigate the co-distribution of type I R-M systems and blaKPC plasmids in K. pneumoniae.
- To determine the prevalence of type I R-M systems in clinical KPC-KP isolates and global strains.
Main Methods:
- Analysis of 459 clinical K. pneumoniae isolates from China.
- Examination of 217 global K. pneumoniae whole-genome sequences from GenBank.
- Assessment of type I R-M system prevalence and distribution.
Main Results:
- Type I R-M systems were found to be scarce in KPC-positive K. pneumoniae, particularly within the high-risk clonal group 258 (CG258).
- Polymorphisms in type I R-M systems indicate their recognition sequences are widespread in K. pneumoniae DNA.
- Type I R-M systems have the potential to target and degrade invading DNA elements, including blaKPC genes.
Conclusions:
- The scarcity of type I R-M systems in KPC-KP suggests they may play a role in restricting the acquisition of blaKPC plasmids.
- Understanding the interaction between R-M systems and plasmids is crucial for combating the spread of antimicrobial resistance.
