Engineered living materials suppress uropathogenic E. coli growth and invasion of urothelial cells through sustained probiotic release.

Recurrent urinary tract infection (rUTI) is a significant public health problem. The most common cause of rUTI is uropathogenic Escherichia coli (UPEC). Antimicrobial prophylactic and therapeutic regimens for rUTI disrupts the microbiome and leads to infection with antimicrobial resistant organisms. Therefore, there is an urgent need to develop microbiome-sparing alternative approaches for preventing rUTI. Asymptomatic bacteriuria (ABU) E. coli strain 83972 (ABEC) outcompetes UPEC in the urinary tract without causing UTI symptoms, but its limited persistence in the bladder restricts its efficacy. Here, we investigate a device made from an engineered living material (ELM) that releases ABEC in a sustained manner as an antibiotic-free platform against UTIs and rUTIs. Using physiologically relevant in vitro models incorporating human urothelial cells, human urine, and periodic urine exchange, we show that ABEC-releasing ELMs suppress UPEC proliferation and inhibit UPEC attachment to and invasion into urothelial cells, particularly when ABEC is maintained at equal or higher levels than UPEC. Because ELMs continuously release ABEC, they sustain competitive pressure even as planktonic bacteria are cleared during voiding, outperforming a single dose of free-floating ABEC. In a rUTI model, sustained ABEC release from ELMs reduces the proliferation and reinvasion of UPEC expelled from infected urothelial cells, while UPEC infiltration into fractured ELMs remains negligible. Finally, we design a first-generation ELM device that can be transurethrally delivered and retained within the mouse urinary bladder, achieving sustained ABEC release in vivo, with ABEC persisting in the bladder, kidneys, and urine for at least 4 days. In summary, we report the development of an ELM device that continuously releases ABEC to suppress UPEC proliferation and urothelial cell invasion in in vitro models of rUTI, and demonstrate sustained ABEC release in vivo in a mouse bladder.