Professor of Medical Microbiology
My early research centred on beta-lactamases, and I showed how an apparently weak activity could protect a bacterium if the enzyme had high affinity and the beta-lactam permeated only slowly. This led to showing that models describing the interplay of beta-lactamase and permeability were adequate for Escherichia coli but not Pseudomonas aeruginosa, and I contributed to work revealing that this inadequacy was because P. aeruginosaalso effluxes beta-lactams. Other early work explored the induction of AmpC ?-lactamases and the selection of AmpC-derepressed mutants from AmpC-inducible populations of Enterobacter and P. aeruginosa, showing selection to be the more important factor. I have been responsible for describing and investigating the properties of many new ?-lactamases, including those conferring resistance to carbapenems – the last reserve beta-lactams against many otherwise multiresistant bacteria.
My work increasingly spread from the mechanisms of resistance to its epidemiology. At the UK Health Protection Agency (Public Health England) I led groups that demonstrated the dramatic rises in MRSA in the late 1990s, ciprofloxacin-resistant gonococci around 2002-3, carbapenemase-resistant Acinetobacter spp. and cephalosporin-resistant E. coli from around 2003 and the recent rise in carbapenemases, partly linked to the repeated import of strains with NDM-1 enzyme via patients previously hospitalised in the Indian subcontinent.
My current major areas of research interest at UEA centre on the development of methods to rapidly detect antibiotic resistant bacteria in patient specimens. Such tests would allow the swifter optimisation of a patient’s therapy, benefitting both the individual and antibiotic stewardship – thus meeting key objectives highlighted in the Chief Medical Officer’s Annual Report for 2013. Other areas of interest are gut carriage of resistant bacteria and the relationship between in-vitro resistance and treatment outcome, Through on-going links with Public Health England I remain deeply involved in the surveillance of antibiotic resistance, the investigation of emerging resistance types and the in-vitro evaluation of new antibiotics against these organisms.