Projects per year
Different weak organic acids have significant potential as topical treatments for wounds infected by opportunistic pathogens that are recalcitrant to standard treatments. These acids have long been used as bacteriostatic compounds in the food industry, and in some cases are already being used in the clinic. The effects of different organic acids vary with pH, concentration, and the specific organic acid used, but no studies to date on any opportunistic pathogens have examined the detailed interactions between these key variables in a controlled and systematic way. We have therefore comprehensively evaluated the effects of several different weak organic acids on growth of the opportunistic pathogen Pseudomonas aeruginosa. We used a semi-automated plate reader to generate growth profiles for two different strains (model laboratory strain PAO1 and clinical isolate PA1054 from a hospital burns unit) in a range of organic acids at different concentrations and pH, with a high level of replication for a total of 162,960 data points. We then compared two different modeling approaches for the interpretation of this time-resolved dataset: parametric logistic regression (with or without a component to include lag phase) vs. non-parametric Gaussian process (GP) regression. Because GP makes no prior assumptions about the nature of the growth, this method proved to be superior in cases where growth did not follow a standard sigmoid functional form, as is common when bacteria grow under stress. Acetic, propionic and butyric acids were all more detrimental to growth than the other acids tested, and although PA1054 grew better than PAO1 under non-stress conditions, this difference largely disappeared as the levels of stress increased. As expected from knowledge of how organic acids behave, their effect was significantly enhanced in combination with low pH, with this interaction being greatest in the case of propionic acid. Our approach lends itself to the characterization of combinatorial interactions between stressors, especially in cases where their impacts on growth render logistic growth models unsuitable.
|Journal||Frontiers in Microbiology|
|Publication status||Published - 8 Jan 2019|
- Gaussian process
- Low pH
- Opportunistic pathogen
- Organic acid
- Parametric (model-based) analysis
- Pseudomonas aeruginosa
ASJC Scopus subject areas
- Microbiology (medical)
FingerprintDive into the research topics of 'Synergistic impacts of organic acids and pH on growth of Pseudomonas aeruginosa: a comparison of parametric and Bayesian non-parametric methods to model growth'. Together they form a unique fingerprint.
- 3 Finished
Wellcome Trust ISSF: Best Practice in Mathematical Model Parametrisation for PredictiveMedicine (1516ISSFFEL9)
20/06/16 → 19/08/16
Maths-AIM: A Mathematical and experimental approach for the rational assessment of bacterial Adhesion Inhibitor Materials in vivo
Jabbari, S. & Krachler, A.
Biotechnology & Biological Sciences Research Council
14/09/15 → 30/11/18
Project: Research Councils
A systems biology approach to understanding and combating Clostridium difficile infection
1/10/12 → 31/05/14
Project: Research Councils