An assessment of antibacterial mode of action of chitosan on Listeria innocua cells using real-time HATR-FTIR spectroscopy

Juthamas Tantala; Kanjana Thumanu; Chitsiri Rachtanapun

doi:10.1016/j.ijbiomac.2019.05.032

An assessment of antibacterial mode of action of chitosan on Listeria innocua cells using real-time HATR-FTIR spectroscopy

Int J Biol Macromol. 2019 Aug 15:135:386-393. doi: 10.1016/j.ijbiomac.2019.05.032. Epub 2019 May 6.

Authors

Juthamas Tantala¹, Kanjana Thumanu², Chitsiri Rachtanapun³

Affiliations

¹ Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand; Center of International Standard Food Safety, Center for Advanced Studies Agriculture and Food, Kasetsart University, Bangkok 10900, Thailand.
² Synchrotron Light Research Institute (Public Organization), Nakhon Ratchasima 30000, Thailand.
³ Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand; Center of International Standard Food Safety, Center for Advanced Studies Agriculture and Food, Kasetsart University, Bangkok 10900, Thailand. Electronic address: chitsiri.t@ku.th.

PMID: 31071397
DOI: 10.1016/j.ijbiomac.2019.05.032

Abstract

The antibacterial mode of action of chitosan using real-time, horizontal attenuated total reflectance, Fourier-transform infrared (HATR-FTIR) spectroscopy and transmission electron microscopy (TEM) was investigated. Listeria innocua was treated with chitosan solution. HATR-FTIR revealed an increased lethality and substantially metabolomics response on cell components. The main changes in FTIR and their 2nd derivative spectra were at 1045 cm^-1 (carbohydrates in cell wall). Principal component analysis clearly segregated untreated and treated cells. Loadings plot revealed the functional groups in cell wall, cell membrane, phospholipid and protein regions of spectrum that are responsible for the classification of treated and control spectra. Kinetic traces of the metabolomics change suggested that cell wall and cell membrane seemed to be the initial target of the antimicrobial mechanism of chitosan. In agreement with the TEM images, which showed breakage of cell wall integrity. The cell wall, cell membrane, phospholipids, proteins and nucleic acids of FTIR spectral data recorded during the cell inactivation were shown to be linked to the metabolomics cell response in the lethality rate and structure of the cells. This work clearly showed, using HATR-FTIR spectroscopy, how bacteria can change their metabolomics response substantially during the first 45 min of contact time.

Keywords: Antimicrobial activity; Chitosan; HATR-FTIR; Listeria; Mode of action.

MeSH terms

Anti-Bacterial Agents / chemistry
Anti-Bacterial Agents / pharmacology*
Chitosan / chemistry
Chitosan / pharmacology*
Kinetics
Listeria / cytology*
Listeria / drug effects*
Listeria / metabolism
Metabolomics
Spectroscopy, Fourier Transform Infrared*

Substances

Anti-Bacterial Agents
Chitosan