Infections with enteric bacteria that exhibit resistance to most or, in some instances, all currently available antibiotics – referred to as the Silent Pandemic – are an emerging human health crisis that threatens the very core of modern medicine and are predicted as the leading cause of death by 2050. Navab’s lab builds knowledge to identify the prevalence and persistence of antibiotic-resistant bacteria and associated genes in wastewater and receiving environments. In an ongoing USDA-funded project, collaborating with 17 Oregon municipalities, we have shown that the removal efficiency of antibiotic- resistant E. coli in wastewater systems is influenced by unit operations and seasonal variations. Our work is the first to report on the prevalence of the clinically relevant extended-spectrum beta-lactamase (ESBL)-producing E. coli and their resistome characteristics in Oregon wastewater. By unique incorporation of hybrid whole-genome sequencing, culture-dependent methods, and metagenomics, Navab’s lab has provided a holistic picture of ESBL-producing E. coli within Oregonian wastewater systems, and by proxy Oregonian communities. Our findings have provided context to the local variations in antibiotic and antibiotic resistance gene abundances in wastewater effluent. Moreover, we have demonstrated faster decay rates of soil antibiotic-resistant E. coli and enterococci as compared with their total counterparts after biosolids amendment in controlled greenhouse settings. Using shotgun metagenomic analysis, we have demonstrated significantly higher diversity and richness in the resistome (i.e., entire ecology of resistance determinants) and microbiome in biosolids-amended soils compared to non-amended soils. Internationally, Navab’s lab has determined the fate of antibiotic- resistant bacteria in Vietnamese septic sludge and environmental soil and has investigated fecal colonization of multidrug-resistant E. coli among healthy infants in rural Bangladesh. Collectively, the aim of our work is to inform future studies on the global surveillance of wastewater antibiotic resistance as well as impacting policies leading to the reduction of illness and death due to antibiotic-resistant infections.
Faculty Lecture Series