Dynamic persistence of UPEC intracellular bacterial communities in a human bladder-chip model of urinary tract infection

Abstract

Uropathogenic Escherichia coli (UPEC) proliferate within superficial bladder umbrella cells to form intracellular bacterial communities (IBCs) during early stages of urinary tract infections. However, the dynamic responses of IBCs to host stresses and antibiotic therapy are difficult to assess in situ. We develop a human bladder-chip model wherein umbrella cells and bladder microvascular endothelial cells are co-cultured under flow in urine and nutritive media respectively, and bladder filling and voiding mimicked mechanically by application and release of linear strain. Using time-lapse microscopy, we show that rapid recruitment of neutrophils from the vascular channel to sites of infection leads to swarm and neutrophil extracellular trap formation but does not prevent IBC formation. Subsequently, we tracked bacterial growth dynamics in individual IBCs through two cycles of antibiotic administration interspersed with recovery periods which revealed that the elimination of bacteria within IBCs by the antibiotic was delayed, and in some instances, did not occur at all. During the recovery period, rapid proliferation in a significant fraction of IBCs reseeded new foci of infection through bacterial shedding and host cell exfoliation. These insights reinforce a dynamic role for IBCs as harbours of bacterial persistence, with significant consequences for non-compliance with antibiotic regimens.

Early invasion of the bladder wall by solitary bacteria protects UPEC from antibiotics and neutrophil swarms in an organoid model

“…Shortcomings of the organoid model in its current form include the absence of resident immune cells (Lacerda Mariano et al, 2020;Schiwon et al, 2014) or vasculature (Homan et al, 2019;Mansour et al, 2018), the accumulation of cell debris in the lumen, and the inability to expose the cells of the umbrella-like layer facing the lumen to urine. Some of these limitations may be addressed with a bladderchip platform (Sharma et al, 2021) or through the development of organoid-on-chip systems (Park et al, 2019;Takebe et al, 2017;Zhang et al, 2018).…”

Phase-In to Phase-Out—Targeted, Inclusive Strategies Are Needed to Enable Full Replacement of Animal Use in the European Union

“…It may be possible to apply organ chips, developed using patient cells, to screen approved drugs and discover potential personalised treatments. As research using the chips, and advances in other cell-based NAMs, evolve so that knowledge and experience accumulate, it becomes apparent that chips can be used to measure increasingly complex parameters such as immune cell recruitment [ 20 , 21 ]; thus, these modern, human biology-based NAMs offer a useful platform to look at drug/combination efficacy as well as safety.…”

Perfusion System for Modification of Luminal Contents of Human Intestinal Organoids and Realtime Imaging Analysis of Microbial Populations

“…Although the strain applied due to perfusion in the experiments here was less than these previous intestine-on-chip devices, earlier versions of the perfusion system used in this paper demonstrated the perfusion system's ability to create strains of ~9.3% on HIOs. Furthermore, the effect of perfusion with perfusion-induced cyclic strain can be used in the future to investigate other biological systems that can be grown as organoids and experience cyclic strain, such as lung [26] or bladder [27] models.…”