A research article published in Journal of Environmental and Public Health has demonstrated the importance of using multiple screening methods in the surveillance of antimicrobial-resistant bacteria in water sources.
Antimicrobial-resistant bacteria are found in all types of environmental waters, and E. coli are particularly significant because of their overall abundance and prevalence of drug resistance. Given that many of these drug-resistant bacteria are pathogenic, it is important to understand how resistance spreads in environmental waters.
A team from Colorado State University, led by Hannah Haberecht and Dr Nora Jean Nealon, analyzed sewer water, surface water, and wastewater treatment plant influent and effluent in Northern Colorado for total detected bacteria, E. coli abundance, and drug resistance in E. coli. Analysis of the wastewater sources revealed that, although total E. coli numbers decreased through the water treatment process as expected, the proportion of antibiotic-resistant E. coli increased in surface water, suggesting further research into potential antimicrobial inputs to rivers is warranted.
The team then carried out phenotypic and genotypic profiling using a broth microdilution assay and whole genome sequencing, respectively. Phenotypic screening revealed diverse resistance patterns between and within water sources, indicating multiple horizontal gene transfers along isolate lineages. Meanwhile, whole genome sequencing identified genes specific to both individual locations and sampling dates, supporting the inclusion of temporal screening in antimicrobial resistance surveillance programs.
The study shows the importance of using both phenotypic and genotypic profiling to monitor drug-resistant E. coli in environmental waters to help prevent the spread of resistant bacteria from waters to animals and humans.
This blog post is distributed under the Creative Commons Attribution License (CC-BY). Illustration by David Jury.