Speakers - 2025

Biography

I am Abebe Mekuria Shenkutie, a postdoctoral fellow at The Hong Kong Polytechnic University, honored to receive the RGC Postdoctoral Fellowship for 2024/25. I earned my Ph.D. in Medical Microbiology in 2021 under the Hong Kong Ph.D. Fellowship, specializing in Microbial Genomics and Bioinformatics. My academic journey includes a master’s in medical microbiology from Addis Ababa University and a bachelor’s in veterinary medicine from Mekelle University. Since 2008, I have been passionately teaching courses in medical microbiology and related disciplines. My research is centered on microbial genomic analysis, antimicrobial resistance, and microbiome studies, with the goal of identifying novel drug targets and biomarkers. By integrating clinical and basic science, I am committed to advancing innovative healthcare solutions to combat emerging microbial diseases

Abstract

Background: The rising prevalence of multidrug-resistant Acinetobacter baumannii, including pan-drug-resistant strains, highlights the need for new therapeutic approaches. Our study identified a small RNA, sRNA00203, that regulates genes linked to biofilm-specific antibiotic resistance. We aimed to assess the therapeutic potential of cell-penetrating peptide conjugates of peptide nucleic acids (PNA) for the targeted inhibition of sRNA00203 and disruption of biofilm-mediated antibiotic resistance.

Methods: We conducted transcriptome analysis alongside the construction of an sRNA00203 knockout strain and the prediction of mRNA targets for sRNA00203. We designed five cell-penetrating peptide conjugates of peptide nucleic acids (CPP-PNA) that are antisense to the sequences of the genes encoding sRNA00203. We then evaluated the effects of the sRNA00203 knockout and the inhibition of a specific region of the sRNA00203 sequence with CPP-PNA on biofilm formation and antibiotic resistance.

Results: Deletion of the sRNA00203-encoding gene resulted in an 85% reduction in biofilm biomass and a 1,024-fold and 128-fold decrease in the minimum biofilm inhibitory concentrations for imipenem and ciprofloxacin, respectively. This deletion also downregulated genes involved in biofilm structure, antibiotic resistance, and adhesion of biofilm cells, as well as the genetic variability (transposases) of A. baumannii. Among the five cell-penetrating peptide conjugates of peptide nucleic acids targeting sequences of genes encoding sRNA00203 tested, the antisense CPP-PNA in 9 to 23 nucleotide regions of sRNA00203 was identified as the most susceptible target to CPP-PNA, significantly lowering minimum inhibitory concentrations (2.5–5 μM) compared to the scramble sequence (MIC > 20 μM) in clinical multidrug-resistant A. baumannii strains. The CPP-PNA spanning 9-23 nt inhibited biofilm formation at a concentration of 2.5 μM

Conclusion: Our findings demonstrate that CPP-PNA antisense to the 9-23 nt region of the gene encoding sRNA00203 can inhibit the expression of sRNA00203 and multiple mRNA targets involved in biofilm formation and antibiotic resistance. The finding warrants a novel strategy wherein small molecules suppress sRNA00203 expression, thus influencing multiple gene targets and serving as gene-targeted antimicrobials, once supported with in vivo animal models and clinical experimental studies.

Keywords: Acinetobacter baumannii, antimicrobial, biofilm, small molecules, small RNA