Urinary tract infections (UTI) are among the most frequently reported infections among older persons. UTI not only causes several days of illness but may have more severe consequences, such as a... Show moreUrinary tract infections (UTI) are among the most frequently reported infections among older persons. UTI not only causes several days of illness but may have more severe consequences, such as a decline in functioning, as well as delirium, dehydration, urosepsis, hospitalization, or even death. Annually, 20% of all older persons visit their general practitioner for a UTI and about 50% of the residents in long-term care facilities (LTCF) get a UTI. This thesis describes the possibilities for and the effects of the prevention of UTI in vulnerable very old persons. The first part of this thesis investigates the effect of infections on functioning and explores which vulnerable very old persons would benefit most from UTI prevention. The second part of this thesis describes the results of the CRANBERRY study. A double-blind randomized placebo-controlled multicentre trial in LTCF. This study investigates the effectiveness and costs of cranberry capsule use in the prevention of clinical UTI. Show less