Release of antibiotics into urban wastewater: A secondary-data based analysis for the input assessment using the city of Dresden as an example

Antibiotics are essential for the successful treatment of bacterial infections. Recently, the increasing number of resistant bacteria and the occurrence of residues of antibiotics in the environment has become the focus of scientific interest. The aim of the cooperative project ANTI-Resist was to investigate the release of antibiotics and the occurrence and distribution of antibiotic resistance in the urban waste water system of the city of Dresden.This article presents the main results of the secondary data analysis for the determination of outpatient and inpatient antibiotic consumption and provides an insight into the complexity of the topic antibiotics in waste water.Based on the data of outpatient prescriptions provided by the AOK PLUS for the period 2005 to 2013, thirteen focus substances were identified to estimate antibiotic consumption. Furthermore, delivery data from the pharmacies of three hospitals in Dresden were available.Depending on the substances investigated, seasonality and age dependency were determined. The results at a regional level were mostly in good accordance with general trends throughout Germany. It should be noted that the total amount of antibiotics used remained nearly constant over the whole period investigated, but the prescription of fluoroquinolones increased. This must be questioned when taking into account the increasingly critical situation in the treatment of Gram-negative bacteria in particular. Examinations of waste water conducted indicated that sewage treatment plants are not able to remove antibiotics or their metabolites completely from waste water. The residues are released into surface waters via the treatment plants. The impact cannot be assessed at the moment and further investigations are necessary.