Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Award

Spring 2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Department of Biology

Advisor(s)

Kyle Seifert

Kevin Caran

James Herrick

Abstract

The increased prevalence of antimicrobial resistant bacteria requires development of new control strategies. Preventative measures such as development of disinfectants and antiseptics with faster killing and anti-biofilm capabilities would help limit the spread of resistance and reduce the incidence of hospital acquired infection. Several series of novel amphiphiles, including three bis-cationic, four tris-cationic and three tetra-cationic double tailed amphiphile series, as well as one hexa-cationic, triple tailed amphiphile series were synthesized and tested for antimicrobial properties. The amphiphiles in this study were previously tested for MIC value against several Gram-positive and negative bacterial species. This work expanded on the antimicrobial capabilities of these amphiphiles by determining time to kill a population of cells, biofilm disruption activity, and synergistic interactions with other compounds. Bis-cationic amphiphiles were the fastest at killing S. aureus, as oX-12,12 killed within 1 minute. Oxacillin, a Gram-positive acting antibiotic, combined with novel amphiphiles against E. coli, had FIC’s ranging from 0.5 to 0.19, indicating synergistic interactions. The highest biofilm disruption activity disrupted 90% of P. aeruginosa preformed biofilms. Synergistic combinations of these amphiphiles with oxacillin and other compounds could prove useful in overcoming bacteria antimicrobial resistant mechanisms. These results contribute to the development of cationic amphiphiles with increased biofilm disruption activity and faster kill time, ultimately better disinfectants and antiseptics that will better reduce the spread of antibiotic resistant pathogens especially in a hospital setting.

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