Rapid and sensitive detection of gram-negative bacteria using surface-immobilized polymyxin B

Although detection of gram-negative bacteria (GNB) in body fluids is important for clinical purpose, traditional gram staining and other recently developed methods have inherent limitations in terms of accuracy, sensitivity, and convenience. To overcome the weakness, this study proposed a method det...

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Bibliographic Details
Published in:PloS one 2023-08, Vol.18 (8), p.e0290579-e0290579
Main Authors: Kang, Hyun-Jin, Lee, Sang-Hoon, Kim, Han-Shin, Jung, Yong Woo, Park, Hee-Deung
Format: Article
Language:English
Subjects:
Analysis
Antibiotics
Bacteria
Bacterial infections
Binding
Biology and Life Sciences
Body fluids
Cell walls
Coupling agents
E coli
Engineering and Technology
Escherichia coli
Fluorescence
Gram-negative bacteria
Gram-positive bacteria
Health aspects
Lipids
Lipopolysaccharides
Medicine and Health Sciences
Methylene blue
Microfluidics
Physical Sciences
Polymyxin B
Research and Analysis Methods
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Summary:Although detection of gram-negative bacteria (GNB) in body fluids is important for clinical purpose, traditional gram staining and other recently developed methods have inherent limitations in terms of accuracy, sensitivity, and convenience. To overcome the weakness, this study proposed a method detecting GNB based on specific binding of polymyxin B (PMB) to lipopolysaccharides (LPS) of GNB. Fluorescent microscopy demonstrated that surface immobilized PMB using a silane coupling agent was possible to detect fluorescent signal produced by a single Escherichia coli (a model GNB) cell. Furthermore, the signal was selective enough to differentiate between GNB and gram-positive bacteria. The proposed method could detect three cells per ml within one hour, indicating the method was very sensitive and the sensing was rapid. These results suggest that highly multifold PMB binding on each GNB cell occurred, as millions of LPS are present on cell wall of a GNB cell. Importantly, the principle used in this study was realized in a microfluidic chip for a sample containing E. coli cells suspended in porcine plasma, demonstrating its potential application to practical uses. In conclusion, the proposed method was accurate, sensitive, and convenient for detecting GNB, and could be applied clinically.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0290579