Screening of Clinical Isolates to produce Quorum-sensing molecules

Authors

  • Hafsah Shaikh Author
    • Conceptualization
    • Data Curation
    • Formal Analysis
    • Writing – Original Draft Preparation
    • Writing – Review & Editing
    • Methodology

DOI:

https://doi.org/10.65459/ezhvnw82

Keywords:

N-acyl homoserine lactones, Quorum sensing, Clinical bacteria, Bioassay screening, Pseudomonas isolates

Abstract

Background: Quorum sensing enables bacterial communication and virulence regulation, contributing to antimicrobial resistance in clinical settings. Screening clinical isolates for QS molecules is essential for developing novel anti-virulence therapies. Objectives: This study aimed to collect and process clinical samples (blood and pus) from patients with suspected bacterial infections, isolate and identify Gram-negative bacterial strains using morphological and biochemical tests, and screen them for N-acyl homoserine lactone (AHL) quorum-sensing molecules via biosensor-based agar plate bioassays to evaluate their potential role in pathogenesis. Methods. Clinical bacterial isolates were obtained from mixed cultures using selective media and streak plating to achieve pure cultures on multiple plates. Five distinct strains were purified and identified via colonial morphology, Gram staining, and biochemical tests. All isolates were screened for N-acyl homoserine lactone (AHL) quorum-sensing (QS) molecules using agar plate bioassays with Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136 biosensors, monitoring violacein pigmentation in double-layer overlays. Results. The isolates were identified as three Pseudomonas spp. (MIC1, MIC2, MIC3), one Klebsiella sp., and one Escherichia coli strain. Only Pseudomonas sp. MIC1 exhibited a strong positive response with CV026, producing brown violacein coloration indicative of short-chain AHLs, with no reaction observed with A136. The remaining four isolates showed no QS activity in either assay. Conclusions. This study highlights the selective production of AHL-mediated QS molecules in clinical Pseudomonas isolates, underscoring their potential role in pathogenesis. These findings support the development of quorum-quenching strategies to mitigate virulence and antimicrobial resistance in nosocomial infections, warranting further genomic and multi-pathway investigations.

Author Biography

  • Hafsah Shaikh

    Institute of Microbiology, University of Sindh Jamshoro

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Published

01-11-2025 — Updated on 02-12-2025

Issue

Vol. 1 No. 1 (2025): November

Section

Research Articles

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Copyright (c) 2025 Hafsah Shaikh (Author)

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How to Cite

Screening of Clinical Isolates to produce Quorum-sensing molecules. (2025). Precision Medicine and Health Journal, 1(1), 21-26. https://doi.org/10.65459/ezhvnw82