01. juli 2019

Biofilm antibiotic resistance: how environmental bacteria fight back beta-lactams antibiotics

Project type: Masters

ProjectAntibiotic resistance description: Antimicrobial resistance is one of the greatest challenges of the 21st century and the contribution of the environmental sector to such worldwide situation was widely recognized in the last years. Wastewater treatment plants are hotspots for antibiotic (AB) resistance proliferation and dissemination. In such settings pathogenic bacteria meet and interact with well-adapted environmental bacteria, under a constant selective pressure of sub-inhibitory concentrations of all know AB. Beta-lactams are AB extensively used in the community and hospital settings and multiresistance towards the different beta-lactam classes is observed in pathogenic but also environmental bacteria. This multiresistance is mainly due to the expression of beta-lactamases, enzymes targeting and hydrolysing the beta-lactam AB, making bacteria resistant and able to fight back the AB action. Most beta-lactamases genes (bla genes) are encoded in plasmids and the share of such genes by conjugation between neighbour bacteria is a crucial part of the collective biofilm AB resistance strategy.

Aim: Study how your closest neighbors in a biofilm influence the bacterial interactions by sharing of the bla gene by conjugation and how this impact on the cooperative antibiotic resistance of wastewater biofilms.  

Approach: The work will involve the growth of biofilms composed by a consortium of 4 different wastewater bacterial species: 1 resistant and 3 sensitive to beta-lactam AB. A drip flow bioreactor will be used to produce the biofilms. The conjugation of the resistant genes, as well as the bacteria and enzyme localization, will be followed by applying techniques such as fluorescence in situ hybridization, confocal microscopy and qPCR. Appropriated training will be provided to the student. This proposal is part of the project awarded with a Marie Curie Individual Fellowship, currently undergoing at the Section of Microbiology: https://www1.bio.ku.dk/microbiology/projects/share_ww/


Supervisors: Søren Sørensen (sjs@bio.ku.dk); Ana Filipa Silva (ana.silva@bio.ku.dk)