Determining if the Natural Antimicrobial Manuka Honey Induces Antibiotic Resistant Viable But Not Culturable Bacteria

Faculty Mentor

Andrea Castillo

Document Type

Poster

Start Date

10-5-2023 9:00 AM

End Date

10-5-2023 10:45 AM

Location

PUB NCR

Department

Biology

Abstract

Bacterial development of antibiotic resistance is a serious threat to public health. Antibiotic resistance occurs through mutation, resistance gene acquisition, and entry into the Viable But Not Culturable (VBNC) dormancy state. VBNC bacteria are genetically identical to their antibiotic susceptible siblings but resist antibiotics because the metabolic processes targeted by the antibiotics are not active. Environmental stresses, including exposure to conventional antibiotics, trigger bacteria to enter the VBNC state; consequently, efforts to develop or identify antimicrobials that induce VBNCs are underway. Manuka Honey (MH) has proven to be a broad-spectrum antimicrobial with many antimicrobial mechanisms to which resistance has not yet been observed. MH is being explored as a treatment for skin and other infections. We hypothesize MH will induce fewer VNBC cells than a traditional antibiotic, tobramycin. To test this hypothesis, we are comparing non-VBNC and VBNCs Staphylococcus aureus populations after treatment with MH or tobramycin. We will identify non-VBNC cells using the viable plate count (VPC) technique that is based on cells being metabolically active and therefore able to grow and produce visible colonies. We will also use a microscopic technique called live-dead (LD) staining that counts both non-VBNC and VBNC cells based on their uptake of a green dye. The VBNC population is determined by subtracting the VPC from the LD cell count. Preliminary results contradict our hypothesis by suggesting that MH induces more VNBCs than tobramycin. We will conduct additional refined experiments with S. aureus and extend our studies to additional skin microbes.

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May 10th, 9:00 AM May 10th, 10:45 AM

Determining if the Natural Antimicrobial Manuka Honey Induces Antibiotic Resistant Viable But Not Culturable Bacteria

PUB NCR

Bacterial development of antibiotic resistance is a serious threat to public health. Antibiotic resistance occurs through mutation, resistance gene acquisition, and entry into the Viable But Not Culturable (VBNC) dormancy state. VBNC bacteria are genetically identical to their antibiotic susceptible siblings but resist antibiotics because the metabolic processes targeted by the antibiotics are not active. Environmental stresses, including exposure to conventional antibiotics, trigger bacteria to enter the VBNC state; consequently, efforts to develop or identify antimicrobials that induce VBNCs are underway. Manuka Honey (MH) has proven to be a broad-spectrum antimicrobial with many antimicrobial mechanisms to which resistance has not yet been observed. MH is being explored as a treatment for skin and other infections. We hypothesize MH will induce fewer VNBC cells than a traditional antibiotic, tobramycin. To test this hypothesis, we are comparing non-VBNC and VBNCs Staphylococcus aureus populations after treatment with MH or tobramycin. We will identify non-VBNC cells using the viable plate count (VPC) technique that is based on cells being metabolically active and therefore able to grow and produce visible colonies. We will also use a microscopic technique called live-dead (LD) staining that counts both non-VBNC and VBNC cells based on their uptake of a green dye. The VBNC population is determined by subtracting the VPC from the LD cell count. Preliminary results contradict our hypothesis by suggesting that MH induces more VNBCs than tobramycin. We will conduct additional refined experiments with S. aureus and extend our studies to additional skin microbes.