Invasion and translocation of uropathogenic Escherichia coli isolated from urosepsis and patients with community-acquired urinary tract infection

Abstract

Uropathogenic Escherichia coli (UPEC) strains are found in high numbers in the gut of patients with urinary tract infections (UTIs). We hypothesised that in hospitalised patients, UPEC strains might translocate from the gut to the blood stream and that this could be due to the presence of virulence genes (VGs) that are not commonly found in UPEC strains that cause UTI only. To test this, E. coli strains representing 75 dominant clonal groups of UPEC isolated from the blood of hospitalised patients with UTI (urosepsis) (n = 22), hospital-acquired (HA) UTI without blood infection (n = 24) and strains isolated from patients with community-acquired (CA)-UTIs (n = 29) were tested for their adhesion to, invasion and translocation through Caco-2 cells, in addition to the presence of 34 VGs associated with UPEC. Although there were no differences in the rate and degree of translocation among the groups, urosepsis and HA-UTI strains showed significantly higher abilities to adhere (P = 0.0095 and P < 0.0001 respectively) and invade Caco-2 cells than CA-UTI isolates (P = 0.0044, P = 0.0048 respectively). Urosepsis strains also carried significantly more VGs than strains isolated from patients with only UTI and/or CA-UTI isolates. In contrast, the antigen 43 allele RS218 was found more commonly among CA-UTI strains than in the other two groups. These data indicate that UPEC strains, irrespective of their source, are capable of translocating through gut epithelium. However, urosepsis and HA-UTI strains have a much better ability to interact with gut epithelia and have a greater virulence potential than CA-UPEC, which allows them to cause blood infection.

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

“…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. As in the present study, Owrangi et al ( 2018 ) verified the ability of UPEC strains to adhere to and invade Caco-2 cells, with 10 4 CFU being recovered from the intracellular compartment.…”

Escherichia coli Bloodstream Infections in Patients at a University Hospital: Virulence Factors and Clinical Characteristics

“…ExPEC is a very important bacterium that is involved in bloodstream infections, and in severe cases, it may lead to death (Owrangi et al, 2018). For the characterization of this infection, it is necessary to consider the bacterial determinants, such as virulence factors, as well as antimicrobial susceptibility and host determinants (Jauréguy et al, 2007; Lefort et al, 2011).…”

“…Escherichia coli is the gram-negative organism most frequently isolated in adult patients with bacteraemia (Mora-Rillo et al, 2015) and in severe cases it may lead to death (Owrangi et al, 2018). The rates of bacteraemia have increased steadily in recent years (De Kraker et al, 2013; Miajlovic et al, 2016).…”

“…The progression of infection is mainly associated with the bacterial capability to survive such defenses. In addition, bacterial virulence properties influence the severity and extent of the infection (Lefort et al, 2011; Owrangi et al, 2018). The presence of E. coli in the bloodstream can result in the induction of a vigorous host inflammatory response that lead to sepsis, which is associated with high morbidity and mortality (Russo and Johnson, 2003; Miajlovic and Smith, 2014).…”

Pathogenicity Factors of Genomic Islands in Intestinal and Extraintestinal Escherichia coli

“…The strains originating from UTIs can also be found in the guts of the patients (Moreno et al, 2008). Accordingly, overgrowing intestinal ExPEC strains can also translocate through the gut epithelium and survive in mesenteric lymph nodes to enter the bloodstream (Bark et al, 1995;MacFie et al, 1999;Ljungdahl et al, 2000;Owrangi et al, 2018). Throughout their progression, ExPEC use numerous capture systems to find the necessary elements, particularly iron, to aid their growth (Braun, 2003).…”