Page 18 - pesta2014_3

-pest-POSTEN Side 18

Doktorgrad

Bakteremier med E. coli og
pneumokokker hos eldre

Astrid Louise Wester
disputerte for ph.d. graden den 23. oktober
2014 ved Universitetet i Oslo.

Avhandlingens tittel: Bacteraemia caused by pneumococci and
E. coli; Age-related differences in diagnostic markers, clinical
presentation, microbial characteristics and outcome.
Hovedveileder: Ulf R. Dahle, Avdeling for næringsmiddelbårne
infeksjoner, Divisjon for smittevern, Folkehelseinstituttet.

Severe infection and sepsis in advanced age is challenging. Elderly
patients often have underlying disease and may present with subtle
symptoms and signs leading to a delay in diagnosis and treatment. The
doctoral work comprised a historic cohort of patients suffering from
bacteremia with bacterial species clearly indicating severe infection,
admitted to Aker University hospital in the period between 1994 and
2004. The main aims were to find out whether advanced age was
associated with certain markers, microbiological and clinical variables, and whether age and age-
related features had an impact on outcome.
In the study of C-reactive protein (CRP) that included 891 patients and 421 controls, indicated that
advanced age was associated with a lower overall diagnostic value of CRP. Likewise, the study
of clinical data in 680 patients indicated an age-associated difference in diagnostic sensitivity in
identifying organ failure between cut-of level ≥2 and ≥3 criteria of the systemic inflammatory response
syndrome (SIRS). Furthermore, elderly patients had a lower number of ”classic” symptoms and a
higher frequency of atypical symptoms, and their general health was more often reduced at admission.
However, the study could not confirm that fever was a less frequent clinical sign of infection in the
elderly. In contrast, age had an independent outcome effect on organ failure and mortality.
Approximately two hundred E. coli isolates were studied. Advanced age was associated neither with
the presence of Shiga toxin genes nor with any of the identified E. coli multi-locus variable number
tandem-repeats analysis (MLVA) genotypes. However, some age-related clinical features were
associated with a certain MLVA genotype.
In conclusion, the doctoral work gives evidence that elderly patients with infection present with more
atypical clinical signs, that CRP and SIRS may underestimate the clinical severity and that advanced
age clearly is a risk factor for poor outcome of infection.