When bacteria are not sensitive to antibiotics they are antibiotic resistant (AR). AR forms a major threat for public health as bacterial infections can no longer be treated by simple antibiotic treatment. Some bacteria are AR by themselves, but often bacteria can acquire resistance by obtaining genetic material (AR genes) from other bacteria, this might happen more likely in environments in which (low) concentrations of antibiotics are present. When antibiotics are taken orally, antibiotic residues and gut bacteria end up via feces into the wastewater treatment plant (WWTP). In this study of Ilse Verburg, the potential role of the wastewater pathway in the dissemination of AR into the environment is investigated.
By growing three different (pathogenic) bacterial species from the wastewater chain we saw that hospital wastewater contained higher concentrations of AR bacteria, which mirrored the antibiotic consumption and concentration in the wastewater. Moreover, all three bacterial species were still present after wastewater treatment (chapter 2). A genomic approach looking at the bacterial composition showed big differences in bacterial communities between wastewater sources and the WWTP (chapter 3). Finally, by in depth investigation of the genetic material of the pathogenic Klebsiella pneumoniae bacteria we saw that bacteria obtained from hospitalized patients suffering from K. pneumoniae infections and bacteria from hospital wastewater contained more genetic material for AR and virulence. Furthermore, bacteria before and after wastewater treatment were genetically related and thus survive the WWTP (chapter 4). Finally, the findings of this study are discussed and ideas for follow-up research is given (chapter 5).
