Dragerschap van Extended-Spectrum Beta-Lactamases (ESBL’s) bij hemodialysepatiënten Retrospectief onderzoek naar het nut van routinematige screening naar ESBL-dragerschap en contactisolatie tijdens dialyseren

Background: Antibiotic resistance due to Extended-Spectrum Beta-Lactamase (ESBL) producing bacteria is rising. When treating infections caused by these bacteria, the choice of antibiotics is limited. Hemodialysis patients are at risk of becoming ESBL-carriers, but epidemiological data towards ESBL-carriage in this specific patient group is scarce. Methods: A single center retrospective research was conducted in which, from March 2009 to March 2012, the prevalence of ESBL-positive dialysis patients was determined during six screening rounds. If patients were tested ESBL-positive, barrier precautions were taken. Subsequently 120 dialysis patients, selected from the six screening rounds, were included in a case control design. A risk factor analysis for ESBL-carriage was conducted. Survival between ESBL-positive versus ESBL-negative patients was compared, and with Amplified-Fragment Length Polymorphism (AFLP)-typing spread of single strains was investigated. Results: During the study period the prevalence of ESBL-positive patients varied from 5,8% to 11,1%, this variation was not significant. The prevalence of the dialysis population corresponded with the prevalence within the regular population of the Deventer region (8,3%). After multi-variate risk factor analysis, antibiotic use preliminary to sampling (OR: 6,167 95%CI: 2,288-16,624) and residence in a long term care facility (OR: 3,697 95%CI: 1,171-11,674) were significant risk factors for ESBL-carriage. Survival did not differ significantly between ESBL-positive and ESBL-negative dialysis patients. AFLP-typing revealed 3 strains colonized more than one patient. Patient to patient spread was considered unlikely. Conclusion: In this single center hemodialysis population, the prevalence of ESBL-positive patients did not change significantly. The prevalence of ESBL-positive bacteria corresponded with the prevalence within the regular population. ESBL-carriage is dependent on multiple factors, in which previous antibiotic use and residence in a long term care facility seem to play an important role. ESBL-carriage is not associated with a decreased survival in hemodialysis patients.

Using Confidence Intervals for Assessing Reliability of Real Tests

Test authors report sample reliability values but rarely consider the sampling error and related confidence intervals. This study investigated the truth of this conjecture for 116 tests with 1,024 reliability estimates (105 pertaining to test batteries and 919 to tests measuring a single attribute) obtained from an online database. Based on 90% confidence intervals, approximately 20% of the initial quality assessments had to be downgraded. For 95% confidence intervals, the percentage was approximately 23%. The results demonstrated that reported reliability values cannot be trusted without considering their estimation precision. Keywords: confidence intervals for reliability; precision of reported reliability; quality assessment of reliability; test-score reliabilit