In recent years, infection control became more challenging due to the increased number of antibiotic resistant bacteria. Consequently, new approaches besides antibiotics are needed. One of them targets reduced microbial adhesion to biomaterials using nano-feature equipped surfaces, e.g. titanium implants for bone and tissue contact. We aim to unravel the causal relationships between nano-roughness of titanium layers and microbial adhesion.
Exemplarily, an Escherichia coli urosepsis isolate that sticks only weakly to surfaces and the strongly surface-binding E. coli ATCC 25922 are compared to the lab strain E. coli ATCC 31608 regarding their adhesive behaviour on 2 and 7 nm rough titanium surfaces. As initial characterization, images of fluorescently labelled, adherent E.coli cells were taken and the number of bacteria on the particular surfaces was quantified using a custom image analysis workflow developed in Python. To gain more insights into the material-contact triggered microbial ”envelope stress response” and to identify the involved triggers, RNA sequencing of adherent and planktonic bacteria was realised. Therefore, isolated RNA was sequenced with Illumina500, reads were assembled and mapped with HISAT2 following differential gene expression analysis by cross validation of the four statistically-based expression analysis tools DESeq, edgeR, limma and DESeq2.
Significant antimicrobial efficacies between the two investigated nano-roughnesses could not be observed, but between the E. coli strains themselves. Preliminary transcriptome analyses data (i) support the expectation that bacteria sense the surface by modifying their genetic response and (ii) indicate no effect of nano-roughness on the bacteria’s adhesion to the investigated surfaces.