RESUMO
Dose-response curves that describe the relationship between antibiotic dose and growth rate in bacteria are commonly measured with optical density (OD) based assays. While being simple and high-throughput, any dose-dependent cell death dynamics are obscured, as OD assays in batch culture can only quantify a positive net change in cells. Time-kill experiments can be used to quantify cell death rates, but current techniques are extremely resource-intensive and may be biased by residual drug carried over into the quantification assay. Here, we report a novel, fluorescence-based time-kill assay leveraging resazurin as a viable cell count indicator. Our method improves upon previous techniques by greatly reducing the material cost and being robust to residual drug carry-over. We demonstrate our technique by quantifying a dose-response curve in Escherichia coli subject to cefotaxime, revealing dose-dependent death rates. We also show that our method is robust to extracellular debris and cell aggregation. Dose-response curves quantified with our method may provide a more accurate description of pathogen response to therapy, paving the way for more accurate integrated pharmacodynamic-pharmacokinetic studies.
RESUMO
BACKGROUND: The Great East Japan Earthquake and the resulting tsunami and nuclear disaster on March 11, 2011 have had a profound and lasting effect on residents of Japan's Fukushima Prefecture, particularly among evacuees. While there continues to be extensive news coverage and academic study of Fukushima Prefecture's recovery, there has been little exploration of individual narratives. This study aims to illuminate some individual stories of medical students at Fukushima Medical University (FMU) who lived in the Prefecture at the time of the Earthquake. METHODS: A qualitative approach was taken in order to investigate individuals' experiences with the goal of adding a personal dimension to quantitative studies on the subject. 10 open-ended ethnographic interviews were conducted with medical students at FMU in years 1-5 who lived in Fukushima Prefecture at the time of the Great East Japan Earthquake. All interviews were audio recorded and transcribed. Transcriptions were reviewed using inductive thematic analysis under the lens of ethnographic anthropology. RESULTS: Three major themes emerged from these interviews: first, that the events following the Earthquake influenced not only these students' decisions to pursue careers in medicine, but the ways in which they hope to practice medicine in the future. Second, that these students were motivated to share their experiences by a want to change Fukushima Prefecture's public image. And lastly, that the students viewed the opportunity to discuss their experiences through these interviews as healing, both for themselves and for the future. CONCLUSIONS: While multiple factors undoubtably contributed these students' medical education, they cite the Earthquake as essential to their approach to their medical careers. Additionally, opportunities for the participants to discuss their experiences following the Earthquake appear to be rare but valued, as the students view their stories as their "legacies." The enduring, burdening effects of the Earthquake appear to have galvanized the participating students to act on behalf of their communities and their Prefecture. Further qualitative studies in more generalizable populations are needed to improve and deepen our understanding of the societal, cultural, and personal impacts of the Great East Japan Earthquake.
