Spreading Patterns of NDM-Producing Enterobacteriaceae in Clinical and Environmental Settings in Yangon, Myanmar

Area of Science:

• Molecular microbiology and infectious diseases
• Antimicrobial resistance epidemiology
• Genomics and plasmid biology

Background:

• Carbapenemase-producing Enterobacteriaceae (CPE) pose a significant global health challenge due to rising carbapenem resistance.
• Understanding the specific dissemination patterns of carbapenemase genes, particularly NDM-type, is crucial, especially in developing countries like Myanmar.
• Previous research has not extensively detailed the molecular epidemiology of these resistance genes in Myanmar's clinical settings.

Purpose of the Study:

• To phenotypically and genetically characterize CPE isolates from clinical and environmental sources in Yangon, Myanmar.
• To determine the dissemination patterns of plasmids carrying NDM carbapenemase genes and their variants.
• To investigate the role of different plasmid types in the spread of NDM carbapenemases in a real-world setting.

Main Methods:

• Isolation and characterization of 91 CPE isolates from clinical (n=77) and environmental (n=14) samples.
• Whole-genome sequencing and plasmid analysis to identify plasmid types and associated carbapenemase genes (blaNDM variants).
• Plasmid transfer experiments at different temperatures to assess transfer efficiency.

Main Results:

• IncFII plasmids carrying blaNDM-5 and IncX3 plasmids carrying blaNDM-4 or blaNDM-7 were the most prevalent.
• IncFII plasmids were mainly found in clinical Escherichia coli isolates, showing clonal expansion within a hospital ward.
• IncX3 plasmids were widespread across nine species in both clinical and environmental samples, demonstrating efficient horizontal transfer, particularly at 25°C.

Conclusions:

• Three distinct dissemination patterns of blaNDM-harboring plasmids were identified in CPE isolates in Myanmar.
• IncX3 plasmids exhibit efficient horizontal transfer, contributing to the widespread dissemination of NDM carbapenemases in diverse hosts and environments.
• The findings provide critical insights into the molecular epidemiology and dissemination of NDM carbapenemases in an endemic setting, informing public health strategies.