Honey bees (Apis mellifera) are important because of their significant contribution to worldwide crop pollination. Colonies are under threat from multiple major pathogens including fungi, viruses, parasites, and bacteria. European foulbrood (EFB) is a bacterial pathogen of the honey bee, and is detected in hives globally. The causative agent Melissococcus plutonius is a gram-positive bacterium that infects the gut of the larva, resulting in death when the bee larvae is between 4-5 days old. Previously, isolates have been differentiated into strain types (STs) and clonal complexes (CC) which vary in virulence level (the severity of disease caused), but the genetic basis of this is still unknown.
Whole genome sequencing of more than 50 M. plutonius isolates, taken from UK EFB outbreaks, speculatively identified genes or genetic features related to increased virulence such as biofilm formation, toxin production, antibiotic resistance, and mobile genetic elements. Subsequently, laboratory-reared honey bee larvae were artificially infected with different M. plutonius strains, to gain further understanding of how the identified hypothetical genetic features may impact disease progression and severity in real EFB infections. M. plutonius isolates were also tested for their susceptibility to the antibiotic oxytetracycline, the only approved antibiotic treatment of EFB in the UK. If the presence or expression of specific bacterial genes can reliably predict disease severity or antibiotic resistance in the lab, then this may improve screening and management of EFB outbreaks in the UK in the future.
After graduating from the University of York with a BSc in Biology (First class), Nicola decided to take a brief break from studying. She spent 18 months at the University of Sheffield as a Research Technician on a project ‘Staphylococcus aureus infection dynamics’ and this solidified her interest in investiging the dynamics of infectious disease. She has recently handed in her thesis titled “Investigating the genetics and virulence of European foulbrood, a bacterial pathogen of honey bees”, based both at the University of York and at the National Bee Unit at Fera Science Ltd. This project received generous support from Bee Diseases Insurance Ltd. in addition to the Biotechnology and Biological Sciences Research Council (BBSRC).