Where is the starting point of frequently occuring infections? Dr. Sebastian Schulz-Stübner from the German consulting centre of hygiene (BZH) and his team is searching for it since 2013 and collects the results in an „outbreak-register“. What are the first experiences? The scientist was interviewed by Carola Timmel.
Mr. Schulz-Stübner, how difficult is it to identify the origin of an outbreak and the dynamic arising from it? Is it easy in the majority of cases to find clear answers?
No, in some cases the mechanism behind the outbreak remains unclear. In order to perform a systematic search for potential links between cases the first week of an outbreak seems to be very important because staff memory of events, treatments, medication and supplies used is still fresh and can be easily aggregated by personal interviews. Later we often depend on written patient records which oftentimes cannot provide the necessary details. The dynamics of an outbreak offer important hints whether a contact transmission or a point source (like contaminated supplies or something in the environment) is the likely cause but the primary hypothesis needs to be constantly re-evaluated during the outbreak in order not miss secondary events.
What do hospitals learn by this process of cause study?
In every outbreak situation there are some lessons to be learned for standard care because all the processes of care are scrutinized as part of the investigation. Mostly there is a chain of events leading to an outbreak and a number of them are not preventable so there should not be any room for blame games during and after an outbreak. However hospitals should seize on the opportunity to constantly learn and adjust accordingly and also share their conclusions and measures with others. To do this in an anonymized way is one of the goals of our database and the resulting publications.
What is the main task of outbreak investigation?
Although the traditional definition of an outbreak in Germany given by the federal infection protection law is the occurrence of two ore more epidemiologically linked nosocomial infections, a growing number of outbreak investigations in the recent past is conducted because of colonization outbreak with multiresistant organisms esp. gram-negative organisms and VRE. Fortunately despite large numbers of colonized patients infections with those acquired organisms are infrequently observed, so we have to differentiate between infection prevention as a primary goal and colonization prevention as a secondary goal of modern hospital epidemiology strategies.
Long term data about the consequences of an outbreak on institutional infection rates in the literature are rare and our database is not designed to answer this question, because it is an anonymized registry of the outbreak investigations only and does not allow for long-term follow up. Such an effort would only be possible with comprehensive research funding and additional resources to collect the necessary data on a large scale over a long period of time.