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Characterization of NDM-5-Producing Escherichia coli Strains Isolated from Pediatric Patients with Bloodstream
Lili Huang1, Hongye Hu2, Chen Xu3
1Laboratory Department, Children's Hospital of Soochow University, Suzhou 215025, China.
Insights
New Delhi Metallo-lactamase-5 (NDM-5) producing Escherichia coli strains cause carbapenem-resistant bloodstream infections in children. These NDM-5 strains carry diverse resistance genes and are transferable, posing a significant public health threat.
Area of Science:
- Microbiology
- Genomics
- Infectious Diseases
Background:
- Escherichia coli bloodstream infections (BSIs) are a leading cause of pediatric mortality globally.
- Carbapenem resistance in E. coli, particularly due to New Delhi Metallo-lactamase-5 (NDM-5), is a growing public health concern.
- Understanding the characteristics of NDM-5 producing E. coli is crucial for effective treatment and control.
Purpose of the Study:
- To investigate the phenotypic and genomic features of NDM-5 producing E. coli strains isolated from pediatric bloodstream infections.
- To identify the antimicrobial resistance profiles and genetic elements associated with NDM-5 in these strains.
- To assess the transferability of the blaNDM-5 gene.
Main Methods:
- Collection and analysis of 114 E. coli strains from pediatric BSIs in Jiangsu province, China.
- Identification of blaNDM-5 carrying strains using molecular methods.
- Antimicrobial susceptibility testing and characterization of additional resistance genes.
- Genomic analysis including sequence typing (STs) and serotyping.
- Plasmid profiling and conjugation experiments to assess gene transfer.
Main Results:
- Eight carbapenem-resistant E. coli strains carrying blaNDM-5 were identified.
- These strains exhibited diverse antimicrobial resistance patterns and belonged to six different sequence types (STs).
- The blaNDM-5 gene was located on transferable plasmids of types IncX3 and IncFII/I1, with transfer frequencies of 10^-6 and 10^-3, respectively.
- Other beta-lactamase genes including blaCMY-2, blaCTX-M, blaOXA-1, and blaTEM-1B were also prevalent.
Conclusions:
- NDM-5 producing E. coli strains are a significant threat in pediatric BSIs due to their carbapenem resistance and co-resistance to other antibiotics.
- The presence of transferable plasmids carrying blaNDM-5 facilitates the spread of carbapenem resistance.
- Effective surveillance and control strategies are essential to mitigate the impact of these multi-drug resistant strains on public health.
Abstract:
Escherichia coli (E. coli) bloodstream infections (BSIs) are among the most predominant causes of death in infants and children worldwide. NDM-5 (New Delhi Metallo-lactamase-5) is responsible for one of the main mechanisms of carbapenem resistance in E. coli. To analyze the phenotypic and genomic characteristics of NDM-5-producing E. coli from bloodstream infections (BSIs), a total of 114 E. coli strains was collected from a children's hospital in Jiangsu province, China. Eight blaNDM-5-carrying E. coli strains were identified which were all carbapenem-resistant and carried diverse antimicrobial resistance genes apart from blaNDM-5. They belonged to six distinct sequence types (STs) and serotypes including one each for ST38/O7:H8, ST58/O?:H37, ST131/O25:H4, ST156/O11:H25 and ST361/O9:H30 and three strains are originating from a single clone belonging to ST410/O?:H9. Apart from blaNDM-5, the E. coli strains isolated from BSIs also carried other β-lactamase genes, including blaCMY-2 (n = 4), blaCTX-M-14 (n = 2), blaCTX-M-15 (n = 3), blaCTX-M-65 (n = 1), blaOXA-1 (n = 4) and blaTEM-1B (n = 5). The blaNDM-5 genes were located on three different types of plasmids, which were IncFII/I1 (n = 1), IncX3 (n = 4) and IncFIA/FIB/FII/Q1 (n = 3). The former two types were conjugatively transferable at frequencies of 10-3 and 10-6, respectively. The dissemination of NDM-producing strains, which exhibit resistance to the last-line antibiotics, carbapenems, may increase the muti-antimicrobial resistance burden among E. coli BSIs and further threaten public health.
