Bacteria can become resistant to antibiotics. And waste water effluent from sewage treatment plants can play a significant role in this process. This is concluded by UK researchers who published their new findings in the Journal of Antimicrobial Chemotherapy.

The researchers took river sediment samples, downstream and upstream of a UK waste water treatment plant in 2009 and 2011. They looked specifically at E. coli bacteria and their resistance against third-generation cephalosporins. This is an important groups of antibiotics, used to treat humans with blood poisoning and brain infections for example.

It was shown that the water after treatment contained seven times more resistant E. coli bacteria than the waste water before it was treated. According to the researchers this is because the sewage treatment plants are a