Date of Publication

11-2024

Document Type

Master's Thesis

Degree Name

Master of Science in Biology

Subject Categories

Biology

College

College of Science

Department/Unit

Biology

Thesis Advisor

Esperanza C. Cabrera

Defense Panel Chair

Llewelyn M. Espiritu

Defense Panel Member

Rich Milton R. Dulay
James Christopher C. Chua

Abstract (English)

The public health issue today of multidrug-resistant bacteria calls for the need to discover new and effective antimicrobial agents. In line with this concern, this work highlighted the quorum quenching (QQ) activities of the crude ethanolic extracts of Pleurotus florida and Pleurotus djamor on extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae clinical isolates and methicillin-resistant S. aureus. The sub-minimum inhibitory concentrations (sub-MIC) of the crude ethanolic extract of each Pleurotus spp. was used to determine the effects on quorum sensing (QS)-mediated phenotypes such as violacein production, biofilm formation, swimming and swarming motility, protease production, methicillin resistance, and gene expression of the luxS and agrA genes. The tested sub-MICs at 6.25 mg/mL, 12.5 mg/mL and 25 mg/mL of the two ethanolic mushroom extracts exhibited no toxicity and did not inhibit the growth of any clinical isolates tested all throughout the assays. However, the sub-MICs of the mushroom extracts effectively inhibited swimming and swarming motility, and biofilm formation in Escherichia coli. Similarly, biofilm formation in Klebsiella pneumoniae was reduced by the mushroom extracts. When compared, the percentage inhibition of biofilm formation by sub-MICs of both Pleurotus spp. was significantly greater in E. coli 168 than in K. pneumoniae 245 (pluxS in E. coli and K. pneumoniae was downregulated, while agrA was not expressed in MRSA in the mushroom extract-treated groups, which further support the inhibition of the quorum-sensing-mediated phenotypes induced by the sub-MIC of the mushroom extracts. In conclusion, these findings suggest that the ethanolic extracts of the two Pleurotus spp. are promising candidates as sources of quorum-sensing inhibitors. Hence, further elucidation of the bioactive compounds responsible for these activities is highly recommended.

Abstract Format

html

Abstract (Filipino)

n/a

Abstract Format

html

Language

English

Format

Electronic

Keywords

Biofilms; Mushrooms; Quorum sensing (Microbiology); Escherichia coli; Klebsiella pneumoniae; Staphylococcus aureus

Upload Full Text

wf_yes

Embargo Period

12-14-2027

Download

Available for download on Tuesday, December 14, 2027

Share

COinS