Fosfomycin_bioreactor

Fosfomycin is a re-emergent antibiotic known to be effective against severe bacterial infections even when other antibiotics fail. To avoid overuse and thus the risk of new antibiotic resistance, the European Commission has recommended the intravenous use of fosfomycin only when other antibiotic treatments fail (EMA, 2020). Therefore, a release of fosfomycin into the environment via wastewater from the manufacturing pharmaceutical industry can seriously undermine a sustaining therapeutic value. We showed in long-term continuous-mode bioreactor cultivation and by using microbial community flow cytometry, microbial community ecology tools, and cell sorting that the micro-pollutant altered the bacterial community composition within a few generations. Under these conditions, fosfomycin was not readily degraded both at lower and higher concentrations. At the same time, alpha-and intra-community beta-diversity values of the wastewater community (WWC) remained roughly on the same level, but higher concentrations of fosfomycin were found to select for organisms known to frequently harbor antibiotic resistance genes (ARGs). A gfp-labelled augmented Pseudomonas putida strain, used as model organism and future possible chassis for fosfomycin degradation pathways was outcompeted in all tested situations. The results suggest that WWCs, as complex communities, could tolerate fosfomycin for a while, but selection for cell types that could develop resistance is very likely. Therefore, the fosfomycin concentration in pharmaceutical wastewater should be reduced as far as possible already in the influent of a wastewater treatment plant in order to minimize the distribution of the antibiotic into the environment via the wastewater.