Fate and effect of amoxicillin in space and terrestrial water reclamation systems



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Texas Tech University


As NASA strives towards long-term manned space travel, wastewater recycling will be necessary to provide adequate water. Contaminants, including pharmaceuticals, may be present if astronauts take medications. The overall effects of pharmaceuticals, specifically antibiotics, in recycled wastewater are unknown. One concern is the development of antibiotic resistance by pathogenic bacteria. Additionally, the effects of antibiotics on biological wastewater recycling systems have not been quantified. The overall objective of this research was to determine the fate of amoxicillin in wastewater reclamation systems. Wastewater recycling systems investigated included both systems and feeds typical of space applications located at Johnson Space Center (JSC) and Texas Tech University (TTU), as well as one terrestrial wastewater recycling system (City of Lubbock's Water Reclamation Plant). The overall objective of this research was further divided into three sub-objectives to determine (1) the fate of amoxicillin in JSC's and TTU's water recovery system; (2) the effects of amoxicillin on treatment efficiency; and (3) the development of antibiotic resistance by the microorganisms in the treatment system.

The results of this study indicate amoxicillin is easily removed in a biological wastewater treatment system. In addition, the post-processing units were capable of removing amoxicillin. Due to the low concentrations of amoxicillin in the JSC-WRS and TTU-WRS, amoxicillin did not affect the treatment efficiency of the system although if concentrations increased above 10 mg/L some inhibition may be possible. Organisms in all systems were resistant to the antibiotics investigated, including many beta-lactam antibiotics and a beta-lactam, beta-lactamase inhibitor combination (amoxicillin with clavulanic acid). In both systems, resistance was present in the system before initiating the amoxicillin experiment. The antibiotic resistance patterns of the LWRP varied monthly; heterotrophic bacteria were resistant to most of the antibiotics investigated during the nine month study. In summary, amoxicillin will not accumulate in biological wastewater treatment systems and treatment efficiency will be unaffected by amoxicillin presence; however, microorganism may develop a resistant to amoxicillin if they are not already resistant to amoxicillin.



Water reuse -- Texas -- Lubbock, Drug resistance in microorganisms, Antibiotics -- Environmental aspects, Space microbiology -- United States