Chronic toxicity of human pharmaceuticals to bacterial communities: evaluation of the mixture toxicity of sulfamethoxazole and trimethoprim.
Författare och institution:
Henrik Johansson (Institutionen för växt- och miljövetenskaper); Sara Brosché (Institutionen för växt- och miljövetenskaper); Tobias Porsbring (Institutionen för växt- och miljövetenskaper); Thomas Backhaus (Institutionen för växt- och miljövetenskaper)
SETAC Europe 19th Annual meeting, 31 May - 4 June, 2009, Göteborg.,
Human pharmaceuticals are mainly emitted into the aquatic environment after use and some occur in detectable levels in aquatic ecosystems. Trimethoprim and sulfamethoxazole, two antibiotics both acting on folic acid synthesis but at different stages, have been found to co-occur. They are also administered in combination when treating urinary tract infections due to their synergistic effects. The aim of the study was to determine if a binary mixture of sulfamethoxazole and trimethoprim exert any synergistic effect on natural bacterial communities, or if the effects were predictable using Independent Action (IA). Glass discs (1,5 cm2) were submerged in the stream of Mölndalsån (20 km East of Gothenburg), on which natural periphyton communities (attached bacterial, microalgal and cyanobacterial communities) were colonised. The periphyton communities were taken into the lab after seven days of colonisation and were exposed to the toxicants in a semi static test for 72 hours. Two different background concentrations of trimethoprim (50nm, 5000nM) were combined with six different concentrations of sulfamethoxazole (16nM – 5000nM). Effects on the periphytic bacteria were measured as changes in metabolic diversity with the so called Biolog Ecoplates®, i.e. changes in the ability of the bacterial communities to utilise 31 different carbon sources. This served as a measure of toxicant-induced effects on bacterial community biomass and taxonomic composition. The combination effects were predictable by IA and no synergistic effects were noticed.
Ämne (baseras på Högskoleverkets indelning av forskningsämnen):
Geovetenskap och miljövetenskap ->
Biologiska vetenskaper ->
Sulfamethoxazole, trimethoprim, bacterial communities
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