Biology subjects

Nahum, Y.

Publications and source records attributed to Nahum, Y..

2 recordsLinked to original sources

bioRxiv2024

Characterization of antibiotic resistance development of E. coli in synthetic and real wastewater

Antimicrobial resistance (AMR) is a major threat to global health and resistant bacterial populations have been observed to develop and spread in and around wastewater. However, in vitro studies on AMR development are typically conducted in ideal media conditions which can differ in composition and nutrient density from wastewater. In this study, we compare the growth and AMR development of E. coli in standard LB broth to a synthetic wastewater recipe and autoclaved wastewater samples from the Massachusetts Water Resources Authority (MWRA). We found that synthetic wastewater and real wastewater samples both supported less bacterial growth compared to LB. Additionally, bacteria grown in synthetic wastewater and real wastewater samples had differing susceptibility to antibiotic pressure from Doxycycline, Ciprofloxacin, and Streptomycin. However, AMR development over time during continuous passaging under subinhibitory antibiotic pressure was similar in fold change across all media types. Thus, we find that while LB can act as a proxy for wastewater for AMR studies in E. coli, synthetic wastewater is a more accurate predictor of both E.coli growth and antibiotic resistance development. Moreover, we also show that antibiotic resistance can develop in real wastewater samples and components within wastewater likely have synergistic and antagonistic interactions with antibiotics. ImportanceAntimicrobial resistance (AMR) ranks among the leading global threats to public health and development. In 2019, bacterial AMR was estimated to have directly caused 1.27 million deaths worldwide and contributed to 4.95 million deaths overall (Murray, C. J., et al., (2022). Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis. The Lancet, 399(10325), 629-655.). With estimations of AMR only getting worse, it is imperative that we understand the complex dimensionalities that drive the genesis of antimicrobial resistance to where it begins-the environment. The paper investigates bacterial growth and AMR in real wastewater samples and highlights the importance of using a media that closely mimics real wastewater in AMR studies, compared to standard lab media like LB broth. This is crucial for understanding how E. coli and other bacteria develop AMR in environments similar to actual wastewater, which can inform more effective strategies to combat AMR in natural and engineered settings.

microbiology↗

bioRxiv2024

Microplastics as a novel substrate for antimicrobial resistance: Effects of concentration, composition, and size on E. coli multidrug resistance

Microplastics (MPs) have emerged as a significant environmental pollutant with profound implications for public health, particularly as substrates to facilitate bacterial antimicrobial resistance (AMR). Recently, studies have shown that MPs may accommodate microbial communities, chemical contaminants and genetic material containing AMR genes. This study investigated the effects of MP concentration, composition, and size on the development of multidrug resistance in Escherichia coli. Specifically, we exposed E. coli to varying concentrations of different MP types, including polyethylene (PE), polystyrene (PS), and polypropylene (PP), across a range of sizes (3-10 {micro}m, 10-50 {micro}m, and 500 {micro}m). Results indicated a direct correlation between MP presence and elevated multidrug-resistant (MDR) in E. coli. Notably, MPs exhibited a higher propensity for facilitating resistance than control substrates such as glass, likely due to their hydrophobicity, greater adsorption capacities, and surface chemistries. Furthermore, we observed that co-culture with MPs resulted in biofilm formation. Notably, we found that the bacteria from passaged MPs formed stronger biofilms once the MPs were removed, associated with changes in motility. Thus, we find that MPs also select for cells that are better at forming biofilms, which can lead to recalcitrant infections in the environment and healthcare setting. Our study highlights the immediate need for comprehensive environmental management strategies to mitigate the risk posed by MPs. ImportanceAntimicrobial resistance is one of the worlds most pressing global health crises, with an estimated 10 million deaths per year forecasted by 2050. With the pipeline of antibiotics running dry, it is imperative that mitigation strategies understand the mechanisms that drive the genesis of antimicrobial resistance. One emerging dimension of antimicrobial resistance is the environment. This study highlights the relationship between a widespread environmental pollutant, (MPs), and the rise of drug-resistant bacteria. While it is known that MPs facilitate resistance through several modes (biofilm formation, plastic adsorption rates, etc.), this study fills the knowledge gap on how different types of MPs are contributing to antimicrobial resistance.

microbiology↗