Microbial drug resistance, Bacterial stress responses, Regulation of gene expression, Mechanisms of biofilm formation
Biocide-antibiotic cross resistance
The main focus of Mark's current work (supported by his fellowship and a project grant from BBSRC) is investigation of how exposure of bacteria to biocides can select for cross resistance to antibiotics. The role of generic stress responses relevant to both biocide and antibiotic resistance are being investigated using a combination of contemporary sequencing, transcriptomic and proteomic approaches to identify key loci involved in increased tolerance to biocides and antibiotics. Most of this work focuses on the food borne pathogen, Salmonella.
Efflux pumps and biofilm formation
Recently Mark has been involved in work demonstrating that multidrug efflux systems have roles beyond solute export in Gram negative bacteria, this includes a requirement for some efflux systems to be intact to form a normal biofilm. Mark supervises a PhD project investigating the mechanisms by which multidrug efflux systems contribute to biofilm formation, again in Salmonella.
Transferable antibiotic resistance
Mark also has an interest in mobile genetic elements which mediate transfer of antibiotic resistance genes; he co-supervises a PhD student with Professor Laura Piddock who has determined the sequence of a plasmid carrying an extended spectrum beta lactamase and designed a PCR based molecular test to follow its epidemiology in isolates around the world. Mark also has an active collaboration with a Nigerian research group where levels of antibiotic resistance are very high and has characterised the nature of resistance genes and plasmids present in Nigeria which may act as a reservoir for spread of resistance around the world.