Nicola Burns

CASE – Genetic and environmental effects on virulence of European foulbrood, a bacterial pathogen of honey bees

About me

After graduating from the University of York with a BSc in Biology, I decided to take a break from studying. I spent 18 months at the University of Sheffield as a Research Technician on a project ‘Staphylococcus aureus infection dynamics’. This solidified my interest in microbiology, but also led to the desire to be in control of my own research. I had worked on American foulbrood, a different honey bee bacterial disease, during my undergraduate project so I knew that this project was right for me.

My project

Honey bees (Apis mellifera) are of importance because of their significant contribution to worldwide pollination and key role in crop pollination. Bee numbers are declining due to a variety of health threats including viruses, fungi, bacteria, climate change and pesticides. European foulbrood (EFB) is a bacterial pathogen (Melissococcus plutonius) of the honey bee that infects the gut of the larva at 4-5 days old. The mechanism of infection and mortality, and how it has evolved is unknown. Transmission of M. plutonius occurs both naturally via honey robbing or swarming, or by human movement of infected equipment and livestock. Treatment options include antibiotics, shook swarming (transferring adult bees to new combs and in severe cases, destruction by burning. Outbreaks are still occurring in the UK.
Currently, the genetic knowledge of M. plutonius is limited. An MLST (Multi-locus sequence typing) scheme was previously developed to allow differentiation of isolates into strain types (STs) and this can often be used to trace outbreaks to their source. Strain types can vary in their persistence, and potentially resistance to antibiotic treatment. Strains are also split into clonal complexes (CC; CC3, CC12, CC13) that vary in virulence. The genetic basis of any isolate virulence differences is unknown. The ability to predict isolate virulence from sequence type or genetic features will improve global control of EFB.

The overarching aim of this project is to link genotypes within and among Clonal Complexes (CC) that have been defined by the MLST, with disease symptoms and the environment in which they occur, and to translate this into an inspection and monitoring scheme that will further contribute to keeping this bee disease under control.

The studentship will address four research areas:
Phylogenetic studies: Building on previous analysis of ST and infection occurrence, what is the spatial and temporal pattern of EFB outbreaks? Can STs or CCs be used reliably to discriminate how serious new outbreaks will be? Does MLST type follow whole genome
Comparative Genomics: isolates will be selected for whole genome sequencing and then be examined for genes related to virulence features such as biofilm formation, toxins, antibiotic resistance and mobile genetic elements. These theoretical genetic differences will be confirmed in vivo using larval experiments.
Antibiotic resistance: do any strains or sequence type show resistance to the antibiotic oxytetracycline (OTC) the antibiotic treatment of choice in the UK? Can this be observed both in the lab using MIC assays and by studying the genome?
Practical applications: there are a number of ways in which the studies may influence screening and management of EFB. If MLST type predicts disease severity, then outbreaks can be prioritized for destruction, and follow up inspection regimes recommended. If some strains are more resistant to antibiotics, then alternative methods should always be used for these outbreaks.

The project combines genomics techniques and analysis at the University of York, with experimental work at Fera, in collaboration with the Bee Unit. This project also receives support from Bee Diseases Insurance Ltd.


Not yet available.