Skip to main content

Research Repository

Advanced Search

Morphological and ultrastructural changes in bacterial cells as an indicator of antibacterial mechanism of action.

Cushnie, T.P. Tim; O'Driscoll, No�lle H.; Lamb, Andrew J.


T.P. Tim Cushnie

No�lle H. O'Driscoll

Andrew J. Lamb


Efforts to reduce the global burden of bacterial disease and contend with escalating bacterial resistance are spurring innovation in antibacterial drug and biocide development and related technologies such as photodynamic therapy and photochemical disinfection. Elucidation of the mechanism of action of these new agents and processes can greatly facilitate their development, but it is a complex endeavour. One strategy that has been popular for many years, and which is garnering increasing interest due to recent technological advances in microscopy and a deeper understanding of the molecular events involved, is the examination of treated bacteria for changes to their morphology and ultrastructure. In this review, we take a critical look at this approach. Variables affecting antibacterial-induced alterations are discussed first. These include characteristics of the test organism (e.g. cell wall structure) and incubation conditions (e.g. growth medium osmolarity). The main body of the review then describes the different alterations that can occur. Micrographs depicting these alterations are presented, together with information on agents that induce the change, and the sequence of molecular events that lead to the change. We close by highlighting those morphological and ultrastructural changes which are consistently induced by agents sharing the same mechanism (e.g. spheroplast formation by peptidoglycan synthesis inhibitors) and explaining how changes that are induced by multiple antibacterial classes (e.g. filamentation by DNA synthesis inhibitors, FtsZ disruptors, and other types of agent) can still yield useful mechanistic information. Lastly, recommendations are made regarding future study design and execution.


CUSHNIE, T.P.T., O'DRISCOLL, N.H. and LAMB, A.J. 2016. Morphological and ultrastructural changes in bacterial cells as an indicator of antibacterial mechanism of action. Cellular and molecular life sciences [online], 73(23), pages 4471-4492. Available from:

Journal Article Type Article
Acceptance Date Jun 28, 2016
Online Publication Date Jul 8, 2016
Publication Date Dec 31, 2016
Deposit Date Jan 24, 2017
Publicly Available Date Jul 9, 2017
Journal Cellular and molecular life sciences
Print ISSN 1420-682X
Electronic ISSN 1420-9071
Publisher Springer
Peer Reviewed Peer Reviewed
Volume 73
Issue 23
Pages 4471-4492
Keywords Antibiotic; Antiseptic; Disinfectant; Mode of action; SEM; TEM
Public URL


Downloadable Citations