2025
PRX Life

Unraveling Direct Correlations between Membrane Nanodomain Reorganization and Antimicrobial Resistance Evolution in Bacterial Cells

Authors:

Srividhya Parthasarathi, Anurag Chaudhury, Jaydeep K. Basu

Keywords:

antimicrobial resistance; AMR; dynamical reorganization; membrane nanoscale organization; lipid dynamics; biochemical signalin; membrane compositional changes.

Abstract:

Bacterial drug resistance is a major global health emergency that requires newer approaches for its detection,
especially those that are rapid and sensitive at the single cell level. One of the major limitations of existing
antimicrobial resistance (AMR) screening is that it relies on culturing bacterial samples, which is time- and
resource-intensive, or on detection of known mutations that impart resistance. Here we provide the first
evidence for the existence of direct correlations between nanoscale dynamical reorganization in Gram-negative
bacterial cell membranes with their evolution of phenotypic resistance under sublethal dosage of the last-line
antibiotic Colistin. While super-resolution fluorescence microscopy in combination with fluorescence correlation
spectroscopy enables probing dynamical lipid nanodomains on single E. coli cells undergoing AMR evolution,
high-resolution atomic force microscopy provides information on nanoscale morphological changes in the same
cell population. Interestingly, our study also reveals intricate correlations between nanoscale bacterial membrane
organization and biochemical signaling responses that eventually drive the evolution of antimicrobial resistance.
In addition, we detect signatures of cooperative lipid motion and dynamic heterogeneity as quantified through
the non-Gaussian parameter, α2, for lipid number fluctuations in the illumination volume. Further, this parameter
is also correlated with the evolution of resistance in the strains. Our study suggests a subtle feedback mechanism
for the emergence of antimicrobial resistance which is initiated by membrane nanoscale organization and lipid
dynamics leading to biochemical signaling that leads to membrane compositional changes. These compositional
changes alter these membrane nanoscale parameters to mitigate the antibiotic mediated stress, and they increase
the survival probability of the cell population, which thus becomes more resistant. Our study could thus lead
to the development of a fundamentally new approach with high resolution and sensitivity that could be used to
infer about antimicrobial resistance evolution, which could also be applicable to other Gram-negative strains and
membrane-targeting antibiotics.