Research at the University of St Andrews School of Medicine


Pathogen evolution and epidemiology

The emergence and spread of bacterial pathogens that have become adapted for survival in hospitals poses a major threat to global health systems. One of the most prevalent organisms causing healthcare-associated infections is S. aureus. Clones of epidemic drug-resistant S. aureus have emerged. First described in 1961 within a year of the introduction of methicillin, successive epidemic strains of healthcare-associated methicillin-resistant S. aureus (MRSA) have spread worldwide. The Holden group uses genomics to investigate the epidemiology and evolution of MRSA, from the global level right down to the patient level on the ward. Using phylogenetic and bioinformatic approaches we investigate the events surrounding the emergence and spread of successful clones of MRSA and the effect that antibiotics have had on shaping the pathogen population.

Pathogen biology and genetics

Progress in sequencing technology have meant that it is possible to capture and investigate the genetic diversity of the pathogen populations. This has opened up new possibilities for probing the biology and genetics of pathogens. Our group are interested in the relationship between a pathogen’s genotype and phenotype, in particular how the genetic makeup of an organism influences its virulence and resistance to antibiotics.


Translational genomics

The high resolution genotyping that whole genome sequencing (WGS) provides, coupled with its ability to capture the genetic content of a pathogen’s genome mean that WGS is revolutionising clinical microbiology and the epidemiology of hospital-associated infections. The capacity of WGS to fingerprint micro-organisms can be used to detect the spread and transmission of infections in hospitals. Our group is part of a multi-disciplinary consortium that is targeting healthcare-associated infection (HAI) in Scotland. The Scottish Healthcare Associated Infection Prevention Institute (SHAIPI) consortium bring together groups from across Scotland with expertise in genomics, informatics, epidemiology, infectious diseases, infection control and policy making to combat HAIs.