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Julie Paulsen MD PhD

 

Resident in Medical Genetics

St.Olavs hospital

On 25 mai 2018, Julie Paulsen defendes her PhD thesis

"Risk and prognosis of bloodstream infections: The influence of obesity and lifestyle, genetic variation, and clinical factors present at the time of infection.
The HUNT study and the Nord-Trøndelag Bacteremia registry"

We analyzed data from the HUNT study, the Nord-Trøndelag bacteremia registry and the Tromsø study to identify risk factors for bloodstream infections (BSI), factors associated with the prognosis of Staphylococcus aureus (S. aureus) BSI, and the effect of infectious diseases specialist consultation on the prognosis and management of patients with S. aureus BSI.

Among 64 027 participants in the HUNT study we identified an association between obesity, inactivity and smoking and the risk of BSI. The associations between these factors and BSI differed by different microorganisms.

In a genome-wide association study of the association between nearly 280 000 common genetic variants and the risk of BSI among 11 991 participants in the HUNT and Tromsø studies, we identified a variant that protects against BSI with gram-positive bacteria. The variant is situated close to genes making up the T-cell receptor. The role of this variant needs to be further characterized in future experiments.

Among 373 patients with S. aureus BSI included between 1996 and 2011, the 30-day all-cause mortality was 27.3%. Older age, burden of chronic diseases, the severity of infection and unknown or pulmonary focus of infection were associated with increased mortality risk.

Finally, we conducted a systematic review of 22 observational studies and 1 protocol for a randomized controlled trial assessing the association between infectious disease specialist consultation and prognosis among patients with S. aureus BSI. Most studies reported improved management among patients who received infectious disease specialist consultation. The prognosis in terms of survival was also improved, however, it is difficult to determine how much of this effect that is due to the intervention, and how much is due to bias.

 

 
 
 
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Arne Mehl MD PhD

Senior Consultant in Infectious Diseases Levanger Hospital

On 16 June 2017, Arne Mehl defended his PhD thesis

Bloodstream infection at Levanger Hospital 2002-2013
Incidence, mortality, antimicrobial resistance, antibiotic treatment, and impact of statin prophylaxis.

At Levanger Hospital in Mid-Norway, 1995 episodes of bloodstream infection were registered from 2002 to 2013. The total incidence of bloodstream infections (episodes per 100,000 person-years) increased from 205 in 2002-2007 to 223 in 2008-2013. The incidence of bloodstream infections was highest among elderly men.

The three most common microbes that led to bloodstream infections were Escherichia coli (34.4%), Streptococcus pneumoniae (11.3%) and Staphylococcus aureus (10.9%). Fewer than 5% of the microbes that we found in blood cultures from patients with bloodstream infections were resistant to the combination of antibiotics recommended by Norwegian health authorities for the treatment of sepsis of unknown origin (penicillin and gentamicin, plus metronidazole if an anaerobic infection is suspected). The incidence of resistant microbes was lower than that reported by most other countries.

We investigated whether survival of bloodstream infections could be related to patients’ use of statins, a type of medicine that lowers cholesterol in the blood, but also has anti-inflammatory effects. We found that among patients who had bloodstream infections with Gram-negative bacteria, the percentage who died was 50% lower among those who were using a statin compared with those who were not. Among those who had bloodstream infection with Gram-positive bacteria, however, there was no difference between those who used a statin and those who did not.