Antibiotic concentrations in raw hospital wastewater surpass minimal selective and minimum inhibitory concentrations of resistant Acinetobacter baylyi strains.

Antibiotics are essential for modern medicine, they are employed frequently in hospitals and, therefore, present in hospital wastewater. Even in concentrations, that are lower than the minimum inhibitory concentrations (MICs) of susceptible bacteria, antibiotics may exert an influence and select resistant bacteria, if they exceed the MSCs (minimal selective concentrations) of resistant strains. Here, we compare the MSCs of fluorescently labelled Acinetobacter baylyi strains harboring spontaneous resistance mutations or a resistance plasmid with antibiotic concentrations determined in hospital wastewater. Low MSCs in the µg/L range were measured for the quinolone ciprofloxacin (17 µg/L) and for the carbapenem meropenem (30 µg/L). A 24 h continuous analysis of hospital wastewater showed daily fluctuations of the concentrations of these antibiotics with distinctive peaks at 7-8 p.m. and 5-6 a.m. The meropenem concentrations were always above the MSC and MIC values of A. baylyi. In addition, the ciprofloxacin concentrations were in the range of the lowest MSC for about half the time. These results explain the abundance of strains with meropenem and ciprofloxacin resistance in hospital wastewater and drains.

Exposure of a single wild boar population in North Rhine-Westphalia (Germany) to perfluoroalkyl acids.

Perfluoroalkyl acids (PFAA) are among the leading chemical pollutants in the twenty-first century. Of these, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) have been widely detected in a large number of animal and environmental samples. Wild boars accumulate PFAA in their livers, but it has not yet been clarified to what extent wild boars of the same population accumulate different PFAA in their livers or whether any conclusions can be drawn from any differences found in regard to environmental contamination. In this study, liver samples from wild boars killed during driven hunts in 2019 and 2020 from a defined forest area in North Rhine-Westfalia, Germany were analyzed for 13 different PFAA. A mean load of 493 µg/kg (± 168 µg/kg) PFAA was measured in 2020. Perfluorosulfonic acids accounted for 87% of the total load in both years, with PFOS dominating this group. These results were similar to those of 14 liver samples collected from other regions of Germany for comparison. In addition, the livers of hunted pregnant sows and fetuses were examined. The load of short-chain perfluorocarboxylic acids (< C8) in the fetus liver was as high as that of the sows, whereas the concentrations of long-chain perfluorocarboxylic acids (≥ C8) were lower than in the dams. This result shows for the first time that fetuses take up PFAA from their mothers in utero. Our study shows that PFAA content in wild boar livers is comparably high in all animals in a local population and indicates a need for further research regarding a nationwide background exposure to PFAA in wild boars and their surrounding environment.