Seminars

Whilemobile genetic elements play a consequential part in bacterial adaptation andantibiotic resistance, relatively little is known about their role inwithin-host pathogen evolution. To explore their function, we constructed acomputational pipeline that identifies variations in gene content amongbacteria of the same strain and applied it to a dataset of over a thousandisolates from recurring urinary tract infections. We discovered that aconsiderable number of pathogens had variations in gene content upon theirrecurrence. The elements belonged to diverse types, including phage,transposon, or plasmid. Notably, some of the mobile elements contained knownantibiotic resistance genes and lead to an increase in the isolate’sresistance. We therefore conclude that changes in gene content are common andrapid, and may be functionally important for clinical outcomes of antibiotictreatment.