Testing the impact of a pmrB mutation on antimicrobial peptide resistance in the bacterium Pseudomonas aeruginosa

Presenter Information

Dominika RogalskaFollow

Presenter Type

UNO Undergraduate Student

Major/Field of Study

Biology

Other

Molecular and Biomedical Biology

Advisor Information

Donald Rowen

Location

MBSC302 - U

Presentation Type

Oral Presentation

Start Date

24-3-2023 2:30 PM

End Date

24-3-2023 3:45 PM

Abstract

Pathogens developing resistance to current chemotherapeutic agents is a growing public health concern worldwide. Antimicrobial peptides (AMP) are a potential source of new chemotherapeutic agents. We have been investigating a novel AMP DASamP2 that was developed by computer aided design by Dr. Wang at UNMC. DASamP2 was observed to be effective against both Gram-negative and Gram-positive bacteria. In order to determine the mechanism of action of DASamP2 and how readily bacteria can develop resistance to the AMP, we attempted to isolate mutants of the Gram-negative bacterium Pseudomonas aeruginosa that were more resistant to DASamP2. Sequencing of the only two mutants that showed a large increase of resistance (8-fold) revealed that both strains had a mutation in pmrB that has been previously observed in a strain with increased resistance to another AMP polymyxin B. To confirm that the mutation in pmrB was responsible for the increased resistance to DASamP2. We have constructed two plasmids that will allow us to either introduce or eliminate the pmrB mutation into P. aeruginosa strains. We have begun to construct strains with either an introduced pmrB mutation or with the pmrB mutation fixed. Preliminary results with these new strains suggest that the mutation in pmrB was solely responsible for the increased resistance to DASamP2 we observed in our two mutants. Our results also suggest that the mechanism of action of DASamP2 is similar to polymyxin B and that high level resistance to DASamP2 does not develop readily.

Scheduling

2:30 -3:45 p.m.

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Mar 24th, 2:30 PM Mar 24th, 3:45 PM

Testing the impact of a pmrB mutation on antimicrobial peptide resistance in the bacterium Pseudomonas aeruginosa

MBSC302 - U

Pathogens developing resistance to current chemotherapeutic agents is a growing public health concern worldwide. Antimicrobial peptides (AMP) are a potential source of new chemotherapeutic agents. We have been investigating a novel AMP DASamP2 that was developed by computer aided design by Dr. Wang at UNMC. DASamP2 was observed to be effective against both Gram-negative and Gram-positive bacteria. In order to determine the mechanism of action of DASamP2 and how readily bacteria can develop resistance to the AMP, we attempted to isolate mutants of the Gram-negative bacterium Pseudomonas aeruginosa that were more resistant to DASamP2. Sequencing of the only two mutants that showed a large increase of resistance (8-fold) revealed that both strains had a mutation in pmrB that has been previously observed in a strain with increased resistance to another AMP polymyxin B. To confirm that the mutation in pmrB was responsible for the increased resistance to DASamP2. We have constructed two plasmids that will allow us to either introduce or eliminate the pmrB mutation into P. aeruginosa strains. We have begun to construct strains with either an introduced pmrB mutation or with the pmrB mutation fixed. Preliminary results with these new strains suggest that the mutation in pmrB was solely responsible for the increased resistance to DASamP2 we observed in our two mutants. Our results also suggest that the mechanism of action of DASamP2 is similar to polymyxin B and that high level resistance to DASamP2 does not develop readily.