Document Type

Paper- Restricted to Campus Access

Publication Date


Faculty Mentor

Anthony Lobo and Mark Ellison


Enterococcus is a genus of bacteria that has developed resistance to macrolide antibiotics like erythromycin. Antibiotic resistance is a growing concern as these resistant bacteria are increasingly harder to treat. Single-walled carbon nanotubes functionalized with erythromycin were used to target erythromycin-resistant Enterococcus. Mechanisms of antibiotic resistance include efflux pumps and ribosomal methylation encoded by the msrC and ermB genes, respectively. Moderately erythromycin resistant enterococci (MEREs) were isolated for genetic analysis. We were able to isolate 18 MEREs. None of the resistant strains tested showed the presence of ermB. The resistant enterococci were tested with free erythromycin and erythromycin that had been conjugated to nanotubes. The minimum inhibitory concentration (MIC) of free erythromycin was less than four micrograms per milliliter in an erythromycin-sensitive strain of E. faecalis. The MIC of erythromycin attached to single walled carbon nanotubes was less than 20 micrograms per milliliter in the sensitive E. faecalis. The resistance to modified and unmodified clarithromycin, another macrolide, was tested in collaboration with Dr. Mark Ellison’s group. It was found that both the unmodified and modified free clarithromycin were able to achieve an MIC of less than four micrograms per milliliter in the sensitive E. faecalis.


Presented as part of the Ursinus College Celebration of Student Achievement (CoSA) held April 23 – April 30, 2020.

The downloadable file is a poster with research findings.


Available to Ursinus community only.