Thesis supervisor: Associate Professor Matti Maimets (UT Department of Internal Medicine, Institute of Clinical Medicine) and Senior Research Fellow Paul Naaber (UT Department of Microbiology, Institute of Biomedicine and
Opponent: Professor Uga Dumpis, dr. med (University of Latvia)
Healthcare-associated infection (HAI) is an infection that patients acquire while receiving treatment for medical or surgical conditions. However, one important risk factor is the patient`s comorbidities. HAI may occur in patients during their hospitalization or after discharge. In Europe HAI is diagnosed in 3.2 million patients every year. The risk of acquiring HAI is significantly higher in intensive care units. The most frequent types of HAI are surgical site infections (SSI) and the severest are bloodstream infections (BSI). HAI surveillance is the cornerstone of prevention since it facilitates the development of appropriate intervention measures.
The aim of the present study was to identify infection rates, outcome, risk factors and etiology of BSI and post-cesarean SSI in Estonia. We also evaluated a multimethod approach to postdischarge surveillance of SSI using a combination of telephone calls to the patients, healthcare worker’s questionnaire, and outpatient chart review.
We conducted three studies: BSI study in three Estonian hospitals as well as the pediatric intensive care unit (PICU) of Tartu University Hospital (TUH), and the study of post-cesarean SSI in the Women’s Clinic of TUH.
We found that infection and case-fatality rates and pathogens of BSI in these three hospitals were consistent with previous investigations. However, our findings may be influenced by low blood culture sampling rate. In PICU we observed high incidence of BSI, which could have been affected by two bacterial outbreaks during the study period. The outbreaks also influenced the spectrum of pathogens and antimicrobial susceptibility data. Case-fatality rate of BSI was low compared to other studies. The main risk factors in both studies were intravascular catheters.
The incidence of post-cesarean SSI was 6%, being lower compared to other studies. After hospital discharge we received information about 95% of patients. Almost half of the cases of SSI were detected during postdischarge surveillance, which emphasises the importance of this approach. We found three risk factors: chorioamnionitis, internal fetal monitoring and surgical wound classes III and IV.
In order to decrease HAI, in the future it is essential to work with the risk factors found as well as to avoid the outbreaks. Implementation of appropriate blood culture sampling practices will increase the quality of diagnostics of BSI. The method we used is suitable for postdischarge surveillance of post-cesarean SSI.