The increase in antibacterial resistance has placed the issue of microbial multi-drug resistance on a global stage (Gurunathan, 2019). This issue poses a threat to human and animal health as well as to the environment (Aslam et al., 2018). It affects not only the efficacy of treatment but also how those treatments are conducted (Friedman, Temkin, & Carmeli, 2016). As a result of this ongoing threat, new treatments that have potent effects on bacteria are necessary. One scientific response to this issue has been the development of multifunctional nanoparticles (NPs)(H. Wang et al., 2018). NPs have the ability to be utilized by its varying modes of action and compatibility with other forms of treatments (Alavi & Rai, 2019). This advantage, when successful, would allow for the lowering of dosage and frequency of treatments required to achieve bacteria-killing (Alavi & Rai, 2019).

Despite a plethora of proposed designs for the improvement of antibacterial treatment, questions remain concerning the mode of action of these new agents. The aim of this study is to develop a protocol facilitating the identification of modes of action of newly formulated antibacterial agents. Our hypothesis is that different modes of action will have distinct effects on the morphology and composition of the cells. To test this, we characterized the structural, physical and molecular changes of a model system, E. coli., before and after treatments using antibiotics with known modes of action. We selected two bactericidal antibiotics: colistin which is a membrane disrupting antibiotic, and streptomycin which is a protein inhibiting antibiotic (Santo-Domingo, Chareyron, Broenimann, Lassueur, & Wiederkehr, 2017; Sun et al., 2019; Thummeepak, Kitti, Kunthalert, & Sitthisak, 2016). We discuss the protocol development and the significant differences observed in the bacterial responses as well as the limitations of the envisioned approach. We conclude by providing a perspective of the impact our findings are expected to have on evaluating new engineers NP treatments.

Thesis Completion




Thesis Chair

Tetard, Laurene


Bachelor of Science (B.S.)


College of Sciences



Degree Program




Access Status

Open Access

Release Date