Invasion of Host Cells and Tissues by Uropathogenic Bacteria

Abstract

Within the mammalian urinary tract uropathogenic bacteria face many challenges, including the shearing flow of urine, numerous antibacterial molecules, the bactericidal effects of phagocytes, and a scarcity of nutrients. These problems may be circumvented in part by the ability of uropathogenic Escherichia coli (UPEC) and several other uropathogens to invade the epithelial cells that line the urinary tract. By entering host cells, uropathogens can gain access to additional nutrients and protection from both host defenses and antibiotic treatments. Translocation through host cells can facilitate bacterial dissemination within the urinary tract, while the establishment of stable intracellular bacterial populations may create reservoirs for relapsing and chronic urinary tract infections (UTIs). Here we review the mechanisms and consequences of host cell invasion by uropathogenic bacteria, with consideration of the defenses that are brought to bear against facultative intracellular pathogens within the urinary tract. The relevance of host cell invasion to the pathogenesis of UTIs in human patients is also assessed, along with some of the emerging treatment options that build upon our growing understanding of the infectious life cycle of UPEC and other uropathogenic bacteria.

Genetic and Virulence Characteristics of a Hybrid Atypical Enteropathogenic and Uropathogenic Escherichia coli (aEPEC/UPEC) Strain

“…However, whether UPEC 252 can interact with the intestinal epithelium and cause disease in the intestinal tract remains to be investigated. Furthermore, the ability to invade the host cells allows bacteria to overcome the actions of the immune system and certain antibiotics (Lewis et al, 2016 ). Especially in female patients, UTIs often recur even after antibiotic therapy (Dielubanza and Schaeffer, 2011 ; Barber et al, 2013 ).…”

“…Studies estimate that ~1-3rd of women up to 24 years old will be affected by UTI, and about 25% of these women will have at least one recurrent UTI in the following 6 months (Foxman, 2014 ). According to Lewis et al ( 2016 ), recurrent UTIs are probably related to the invasiveness, persistence, and multiplication of bacteria within the urinary epithelium. Although the internalization rates of UPEC 252 were considerably lower than those of a classical invasive strain ( S. flexneri ), our findings evidenced the ability of this strain to invade the three different cell lines tested (HeLa, HEK293T, and Caco-2), suggesting that it may cause recurrent UTI, or even persistent diarrhea, since it was also able to invade differentiated intestinal Caco-2 cells.…”

Common Traits Spark the Mitophagy/Xenophagy Interplay

“…There are a variety of methods that pathogens exploit to avoid lysosomal degradation. These include: (i) creating a neutral compartment within cells where the pathogen can replicate and then escape as exploited by Brucella abortus ( Case and Samuel, 2016 ); (ii) Hijacking the pathway and persisting within quiescent membrane reservoirs inside the autophagosome to later re-establish recurrent infections as done by the uropathogenic Escherichia coli (UPEC) ( Mulvey et al, 2001 ; Mysorekar and Hultgren, 2006 ; Lewis et al, 2016 ); (iii) Mycobacterium Tuberculosis (MT) instead, prevents the maturation of the phagosome into the autolysosome by releasing inhibitory factors of the likes of ESAT-6 and Rab5 ( Chandra et al, 2015 ; López de Armentia et al, 2016 ; Russell, 2016 ).…”

Selective Uropathogenic <em>E. coli</em> Detection using Crossed Surface Relief Gratings

“…In over 80% cases of UTIs, the primary culprit is Uropathogenic Escherichia coli (UPEC), which is also a major cause of many community-and healthcare-associated diseases [3,4]. The immune system controls the susceptibility of UTIs in humans and, depending on the individual's immunity, UPECs may invade the epithelial cell lining along the urinary tract, where they grow and multiply, invading eventually other sites via the bloodstream [5,6]. UPEC detection in laboratories usually involves biochemical assays like nitrite and/or esterase tests using serological techniques, which suffer from a high probability of false-positive results [7].…”