A study published in the Journal of Global Antimicrobial Resistance has uncovered compelling genetic evidence that drug-resistant bacteria found in Iowa’s natural waterways may be closely related to strains infecting hospital patients. The research highlights the potential for clonal spread of carbapenemase-producing Escherichia coli (CPE) between clinical and environmental settings.
Researchers isolated a highly drug-resistant E. coli strain, designated BO1, from a creek in Northwest Iowa. Genetic sequencing revealed that BO1 carried the blaNDM-5 gene, which confers resistance to carbapenems—antibiotics often used as a last resort. The strain was identified as sequence type ST167, a globally recognized high-risk clone.
Key findings include:
- BO1 was resistant to 15 out of 20 tested antibiotics, classifying it as extensively drug-resistant.
- Whole-genome sequencing showed BO1 differed by only one single-nucleotide polymorphism (SNP) from a clinical strain (IA0018) isolated from a hospital patient in the same region and time period.
- Both strains shared identical resistance genes and plasmid types, suggesting a common origin or recent transmission event.
- The study also identified a conserved genetic environment surrounding the blaNDM-5 gene, indicating potential for horizontal gene transfer.
The findings raise concerns about the environmental persistence and spread of antimicrobial-resistant bacteria, particularly in areas where treated wastewater and agricultural runoff enter natural water systems.
The authors emphasize the importance of continued surveillance and improved wastewater treatment to prevent the transmission of resistant pathogens between healthcare and environmental settings.
The full article is available at the Journal of Global Antimicrobial Resistance.