Dr CAI Zhao
Research Fellow

Pseudomonas aeruginosa PAO1 is a Gram negative, opportunistic pathogen which causes serious medical problems in patients due to their capability to form antibiotic resistant biofilms. The formation of such biofilm can be regulated by bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP). Identification of biomarkers related to c-di-GMP might provide alternative path to diagnose biofilm-related infections. However, there is lack of a largescale systematic investigation of the metabolome of biofilm bacterial cells. Comparative metabolomics characterisation of bacterial cells with different intracellular c-di-GMP levels will facilitate identification of biomarkers of biofilm formation, antibiotic resistance as well as efficacy of dispersal chemistry that aims at controlling c-di-GMP levels.

My research focus is on the identification of potential common cyclic-di-GMP regulated biomarkers among different Gram-negative bacteria via transcriptomic and metabolomics profiling and on the identification of potential biomarkers of different life-styles of Pseudomonas aeruginosa. Bacterial cells can adapt to different life styles, planktonic, biofilm, and dispersed, depending on environmental cues. Biofilm infections are involved in almost 80% of all microbial infections. Biofilm infections can evade the detrimental actions of immune responses and develop into chronic conditions which cannot be efficiently eradicated by conventional antimicrobials. The formation of such biofilms was found to be greatly regulated by c-di-GMP. Variations in amount of intracellular c-di-GMP may change cellular metabolic profile and lead to expression of specific biomarkers. Thus, my project focuses on the identification of biomarkers modulated by c-di-GMP which might provide alternative method to diagnose biofilm-related infections by applying RNA-sequencing (RNA-seq) and high-performance liquid chromatography (LC/MS) techniques to analyse transcriptomics and metabolomics, for the discovery of possible common cross-species biomarkers, as well as life-style specific biomarkers. Currently, I am developing my skills on metagenomics analysis, which will be also my future research focus.