Anatomy and Physiology of the Urinary Tract: Relation to Host Defense and Microbial Infection

Abstract

The urinary tract exits to a body surface area that is densely populated by a wide range of microbes. Yet, under most normal circumstances, it is typically considered sterile, i.e., devoid of microbes, a stark contrast to the gastrointestinal and upper respiratory tracts where many commensal and pathogenic microbes call home. Not surprisingly, infection of the urinary tract over a healthy person’s lifetime is relatively infrequent, occurring once or twice or not at all for most people. For those who do experience an initial infection, the great majority (70% to 80%) thankfully do not go on to suffer from multiple episodes. This is a far cry from the upper respiratory tract infections, which can afflict an otherwise healthy individual countless times. The fact that urinary tract infections are hard to elicit in experimental animals except with inoculum 3–5 orders of magnitude greater than the colony counts that define an acute urinary infection in humans (105 cfu/ml), also speaks to the robustness of the urinary tract defense. How can the urinary tract be so effective in fending off harmful microbes despite its orifice in a close vicinity to that of the microbe-laden gastrointestinal tract? While a complete picture is still evolving, the general consensus is that the anatomical and physiological integrity of the urinary tract is of paramount importance in maintaining a healthy urinary tract. When this integrity is breached, however, the urinary tract can be at a heightened risk or even recurrent episodes of microbial infections. In fact, recurrent urinary tract infections are a significant cause of morbidity and time lost from work and a major challenge to manage clinically. Additionally, infections of the upper urinary tract often require hospitalization and prolonged antibiotic therapy. In this chapter, we provide an overview of the basic anatomy and physiology of the urinary tract with an emphasis on their specific roles in host defense. We also highlight the important structural and functional abnormalities that predispose the urinary tract to microbial infections.

Genotypic detection of the virulence factors of uropathogenic Escherichia coli isolated from diarrheic and urinary tract infected patients in Khartoum State, Sudan

“…While the role of type 1 fimbriae in virulence is unknown, it is well defined that specific adherence and increased induction of mucosal inflammation are the mechanisms used by P fimbriae to increase the virulence of UPEC (Connell et al, 1996). Significant association (p-value 0.006) was found between fimH gene and gender; this association may be due to difference in anatomical structure of urinary tract between male and female (Hickling et al, 2015). The results confirmed the existence of aer gene with more prevalence in diarrheal isolates, this finding totally agreed with Oswald et al (1991), who found that aer gene was positive in 70% of diarrheal samples and Micenková et al (2014) who found aer gene was positive in 68%.…”

Effect of heavy metals on the readaptive processes in the urinary bladder

“…Furthemore, we have shown that the sequences of intensity and depth of pathological lesions were dependent on the duration of the experiment 18 . Nevertheless, more recent research has shown that the that long-term of HMS exposure leads to increases of HM accumulation level in the UB tissue which influence significantly on the morphometric parameters of organ wall thickness (this data has not been published yet).A lot of simulated studies demonstrated that the organ easily exposed to development of inflammatory diseases of various genesis that accompanied by urodynamic disorders 15,17 . A considerable amount of scientific data on associate disruption of the level of physiological concentrations trace elements with the development of oncological pathology of the bladder and other different organshas been published 9,10,[19][20][21] .…”

“…An important role in the removal of metabolism products and toxins is given to the urinary bladder (UB). This organ has functional peculiarities and provides long and controlled urine store in its cavity 15 . It is proved that wide range of factors can affect the development of its pathological changes and dysfunctions [15][16][17] .…”

“…This organ has functional peculiarities and provides long and controlled urine store in its cavity 15 . It is proved that wide range of factors can affect the development of its pathological changes and dysfunctions [15][16][17] . Despite many scientific advances, the data on the mechanisms and dynamics of the development of recovering processes is rarely found in the literature.…”

A non-canonical autophagy-dependent role of the ATG16L1T300A variant in urothelial vesicular trafficking and uropathogenic Escherichia coli persistence

“…In a healthy bladder, the plasma membranes of superficial epithelial cells contain hexagonal arrays of UPK proteins, which are transported by discoidal storage vesicles and multivesicular bodies (MVBs) and are critical for normal epithelial flexibility and barrier function [33,34]. Previous work has demonstrated a role for ATG16L1 in superficial cell vesicular trafficking in mice globally hypomorphic for Atg16l1 [22].…”