Phages in urban wastewater have the potential to disseminate antibiotic resistance

A total of 29 Escherichia coli phages were isolated from wastewater samples collected from an urban wastewater treatment plant and were characterised by host range determination, transmission electron microscopy, antibiotic resistance gene identification and phage transduction. β-Lactam resistance genes (blaCMY, blaTEM, blaSHV, blaCTX-M and blaOXA) were amplified on phage DNA by PCR. Of nine host range patterns observed, six were able to multiply in three or more indicator strains, including Shiga toxin-producing E. coli (STEC). Twelve E. coli phages were able to grow in all four E. coli O157 strains tested. The blaTEM gene was detected in 15 phages, of which 6 were able to transduce blaTEM into E. coli ATCC 13706. These data suggest that phages with broad host range are prevalent in the urban environment and can serve as a natural reservoir of antibiotic resistance genes. These phages can also transfer antibiotic resistance genes via phage transduction and may contribute to the dissemination of antibiotic resistance in the environment.