Digital Public Defence: Chris Noone
MSc John Christopher Noone at Institute of Clinical Medicine will be defending the thesis “Improved characterization and identification of causative microbial agents in orthopedic implant-associated infections using next-generation sequencing” for the degree of PhD (Philosophiae Doctor).
Photo: DL Bordin.
The public defence will be held as a video conference over Zoom.
The defence will follow regular procedure as far as possible, hence it will be open to the public and the audience can ask ex auditorio questions when invited to do so.
Due to copyright reasons, an electronic copy of the thesis must be ordered from the faculty. In order for the faculty to have time to process the order, it must be received by the faculty no later than 2 days prior to the public defence. Orders received later than 2 days before the defence will not be processed. Inquiries regarding the thesis after the public defence must be addressed to the candidate.
Digital Trial Lecture – time and place
- First opponent: Professor John WA Rossen, University of Groningen, Faculty of Medical Sciences
- Second opponent: Associate Professor Anne-Merethe Hanssen, UiT - The Arctic University of Norway
- Third member and chair of the evaluation committee: Professor Henrik Schirmer, University of Oslo
Chair of the Defence
Professor Emeritus Tom Øresland, Faculty of Medicine, University of Oslo
Researcher Hege Vangstein Aamot, Akershus University Hospital
The consequences of orthopedic implant associated infections (OIAI) can be severe. They include extended hospital stays, additional treatment, revision surgery, and increased postoperative mortality. Conventional OIAI diagnostics are culture-based, and hence can require days before results can be reported. A rapid OIAI diagnostic protocol and better insight into the pathogenicity of these infections can foster more timely targeted treatment, and better patient outcome.
In Improved Characterization and Identification of Causative Microbial Agents in Orthopedic Implant-associated Infections Using Next-generation Sequencing, J. Christopher Noone and coworkers have evaluated the potential of next-generation sequencing (NGS) to improve OIAI diagnostics. NGS was used with two goals in mind: 1) to improve molecular characterization of the bacteria that cause OIAI, possibly revealing infection-specific characteristics; and 2) to identify bacterial species and antimicrobial resistance (AMR) genes more rapidly than conventional culture-based methods.
Staphylococcus aureus is one of the most common infecting agents of femoral neck fracture patients treated with hemiarthroplasty. This patient group has a comparatively high incidence of 1-year mortality upon the establishment of an OIAI. A bacterial genome-wide association study was performed with the intent of elucidating bacterial genetic characteristics specific to the S. aureus of hip hemiarthroplasty associated infections, possibly explaining this high mortality. No such genetic characteristics were detected, supporting the premise that all S. aureus have the ability to cause OIAI given the opportunity.
An assessment of conventional culture-based diagnostics showed that culture-based microbiological analysis required 2-3 days from sample arrival to the identification of bacterial species and AMR phenotype. Therefore, a new culture-independent rapid diagnostic protocol was tested and compared to conventional methods. Shotgun metagenomic sequencing was carried out, meaning that all DNA in a sample is sequenced. The near real-time analysis capabilities of nanopore sequencing permitted the identification of OIAI bacterial species and AMR genes in as little as a single workday. Additionally, samples containing sufficient bacterial concentrations allowed for genotyping and the detection of virulence genes, which have implications in the tracing of outbreaks and the implementation of targeted treatment.
NGS technology facilitates a better understanding of the bacteria that cause OIAI. Additionally, an NGS-based rapid diagnostic protocol makes it possible to expedite the precision treatment of OIAI patients, reducing it from several days to one workday.
Contact the research support staff.