Brian Spratt is an expert in bacterial populations and evolutionary biology. In the 1970s, he identified the physiological ‘killing’ targets of penicillin and cephalosporin antibiotics — penicillin-binding proteins, or PBPs — and demonstrated their role in bacterial cell division, elongation and shape. Brian showed that resistance to penicillin in clinical isolates of several major pathogens, including those that cause pneumonia, sepsis, meningitis and gonorrhoea, occurs by the shuffling of regions of PBP genes with corresponding regions from related species.

He demonstrated the importance of this gene shuffling (or recombination) in bacterial populations and showed the range of population structures, from clonal to non-clonal, amongst bacterial species. He also developed new methods to characterise and track the spread of strains of bacterial pathogens, notably multilocus sequence typing (MLST).

Outside the laboratory, Brian has delivered a number of diverse reviews for public bodies, including reports on depleted uranium for the Royal Society and foot and mouth biosecurity for Defra. He has received several national and international prizes and is a Fellow of the American Academy of Microbiology.