Classical chaperone-usher (CU) adhesive fimbriome: uropathogenic Escherichia coli (UPEC) and urinary tract infections (UTIs)

FimH and Anti-Adhesive Therapeutics: A Disarming Strategy Against Uropathogens

“…It is reported that more than 60% of UPEC strains carry 5 to 15 CU fimbriae [33]. Type 1, type 3, type 9, S, P, F1C and Auf are the most common CU fibers among UPEC pathotypes [5,31]. The first characterized virulence adhesive factors of UPEC were the type P fimbriae, encoded by the pap (pyelonephritis-associated pili) genes, which are significantly prevalent among the strains of UPEC that cause pyelonephritis [13].…”

“…This pilus is structurally similar to type 1 pili, and exhibits the adhesin PapG at its tip. Importantly, among UPEC pathotypes, three different alleles for the PapG adhesin, including PapGI, PapGII and PapGIII, have been recognized, with class II being the allele predominantly associated with human pyelonephritis, and class III correlated with human cystitis [5,34]. Different from type 1 pili, it is also known as a mannose-resistant pilus, because it does not interact with mannose sugar residues but with galabiose saccharide residues.…”

“…In addition, Kpc fimbriae, encoded by the kpcABCDEFG gene cluster, and the recently discovered new CU fimbriae encoded by the kpj cluster, have been observed in K. pneumoniae, emphasizing the need for CU fimbrial redundancy of this microorganism [41,44]. Altogether, these fimbriae represent the arsenal of UPKP adhesins; type 1 pili are mainly involved in the interaction with bladder epithelial cells, whereas the others are mostly involved in the adhesion to abiotic surfaces (e.g., medical devices) and in biofilm formation [5,42,45]. It has been shown that type 3 pili together with type 1 are strictly required to cause catheter-associated UTIs (CAUTIs), a common hospital-acquired infection [45].…”

Differential epidemiology and antibiotic resistance of lactose-fermenting and non-fermenting Escherichia coli: Is it just a matter of taste?

“…Members of the Enterobacterales order (previously: the Enterobacteriaceae family (Adelou et al 2016)) are the most frequently associated with UTIs (including E. coli and Klebsiella, Citrobacter, Enterobacter, Serratia, Proteus, Morganella and Providencia species) (Park et al 2017;Critchley et al 2019); however, the pathogenic potential of Gram-positive cocci (Enterococcus spp., Staphylococcus aureus, S. saprophyticus), non-fermenting Gram-negative bacteria (e.g., Pseudomonas aeruginosa) (Gajdács et al 2019b) and various yeasts (e.g., Candida species) should also be taken into consideration (Behzadi et al 2015;Gajdács et al 2019c). Nevertheless, the most common bacterial pathogen in UTIs is E. coli (namely uropathogenic E. coli or UPEC, recognized as a separate microbiological entity in the 1970s), corresponding to 70-95% of infections, based on various literature reports (Gajdács et al 2019d;Behzadi 2019;Hozzari et al 2020). E. coli is a commensal microorganism abundantly found in the gastrointestinal tract (producing Vitamin K for the host and having a protective role against other pathogens); however, if these bacteria breach into other anatomical regions, they act as opportunistic pathogens, owing to the plethora of virulence factors they possess (Gajdács et al 2019d;Behzadi 2019;Hozzari et al 2020;Jahandeh et al 2015).…”

“…Nevertheless, the most common bacterial pathogen in UTIs is E. coli (namely uropathogenic E. coli or UPEC, recognized as a separate microbiological entity in the 1970s), corresponding to 70-95% of infections, based on various literature reports (Gajdács et al 2019d;Behzadi 2019;Hozzari et al 2020). E. coli is a commensal microorganism abundantly found in the gastrointestinal tract (producing Vitamin K for the host and having a protective role against other pathogens); however, if these bacteria breach into other anatomical regions, they act as opportunistic pathogens, owing to the plethora of virulence factors they possess (Gajdács et al 2019d;Behzadi 2019;Hozzari et al 2020;Jahandeh et al 2015). E. coli is considered a biochemically active microorganism, while the hallmarks of biochemical identification include the ability to ferment lactose (lac +) and the decomposing of tryptophan into indole (Toledo and Trabulsi 1983).…”