scholarly journals Increased Type 1 Fimbrial Expression among Commensal Escherichia coli Isolates in the Murine Cecum following Catabolic Stress

1999 ◽  
Vol 67 (2) ◽  
pp. 745-753 ◽  
Author(s):  
Barbara A. Hendrickson ◽  
Jun Guo ◽  
Robert Laughlin ◽  
Yimei Chen ◽  
John C. Alverdy

ABSTRACT Although indigenous bacteria intimately colonize the intestinal mucosa, under normal conditions the intestinal epithelial cell is free of adherent bacteria. Nonetheless, commensal bacteria such asEscherichia coli adhere to and translocate across the intestinal epithelium in association with a number of pathologic states including hemorrhagic shock, immunosuppression, traumatic tissue injury, and lack of enteral feedings. The adhesins involved in the adherence of indigenous E. coli to the intestinal epithelium in vivo following catabolic stress are unknown. We have developed a mouse model to study the bacterial adhesins which mediate the increased intestinal adherence of E. coliafter partial hepatectomy and short-term starvation. Our studies demonstrated that hepatectomy and starvation in the mouse were associated with a 7,500-fold increase in the numbers of E. coli bacteria adhering to the cecum. In addition, erythrocyte agglutination studies, as well as immunostaining of fimbrial preparations and electron micrographs of the bacteria, revealed that surface type 1 fimbriae were more abundant in the commensal E. coli harvested from the ceca of the stressed mice. These E. coli isolates adhered to a mouse colon cell line and injected cecal loops in a mannose-inhibitable manner, which suggests a role for type 1 fimbriae in the adherence of the E. coli isolates to the cecum in vivo following host catabolic stress.

1998 ◽  
Vol 66 (7) ◽  
pp. 3303-3310 ◽  
Author(s):  
Jean K. Lim ◽  
Nereus W. Gunther ◽  
Hui Zhao ◽  
David E. Johnson ◽  
Susan K. Keay ◽  
...  

ABSTRACT Type 1 fimbriae, expressed by most Escherichia colistrains, are thought to attach to human uroepithelium as an initial step in the pathogenesis of urinary tract infections (UTI). Numerous reports using both in vitro and murine models support this role for type 1 fimbriae in colonization. Unfortunately, only a limited number of studies have directly examined the expression of fimbriae in vivo. To determine whether type 1 fimbrial genes are transcribed during an acute UTI, we employed a modification of an established method. The orientation (ON or OFF) of the invertible promoter element, which drives transcription of type 1 fimbrial genes, was determined by PCR amplification using primers that flank the invertible element, followed by SnaBI digestion. The orientation of the type 1 fimbrial switch was determined under three experimental conditions. First,E. coli strains from different clinical sources (acute pyelonephritis patients, cystitis patients, and fecal controls) were tested under different in vitro culture conditions (agar versus broth; aerated versus static). The genes in the more-virulent strains (those causing acute pyelonephritis) demonstrated a resistance, in aerated broth, to switching from OFF to ON, while those in fecal strains readily switched from OFF to ON. Second, bladder and kidney tissue from CBA mice transurethrally inoculated with E. coli CFT073 (an established murine model of ascending UTI) was assayed. The switches directly amplified from infected bladder and kidney tissues were estimated to be 33 and 39% ON, respectively, by using a standard curve. Finally, bacteria present in urine samples collected from women with cystitis were tested for type 1 fimbria switch orientation. For all 11 cases, an average of only 4% of the switches in the bacteria in the urine were ON. In 7 of the 11 cases, we found that all of the visible type 1 fimbrial switches were in the OFF position (upper limit of detection of assay, 98% OFF). Strains recovered from these urine samples, however, were shown after culture in vitro to be capable of switching the fimbrial gene to the ON position and expressing mannose-sensitive hemagglutinin. The results from experimental infections and cases of cystitis in women suggest that type 1 fimbrial genes are transcribed both in the bladder and in the kidney. However, those bacteria found in the urine and not attached to the uroepithelium are not transcriptionally active for type 1 fimbrial genes.


1996 ◽  
Vol 183 (3) ◽  
pp. 1037-1044 ◽  
Author(s):  
M Hedlund ◽  
M Svensson ◽  
A Nilsson ◽  
R D Duan ◽  
C Svanborg

Escherichia coli express fimbriae-associated adhesins through which they attach to mucosal cells and activate a cytokine response. The receptors for E. coli P fimbriae are the globoseries of glycosphingolipids; Gal alpha 1-->4Gal beta-containing oligosaccharides bound to ceramide in the outer leaflet of the lipid bilayer. The receptors for type 1 fimbriae are mannosylated glycoproteins rather than glycolipids. This study tested the hypothesis that P-fimbriated E. coli elicit a cytokine response through the release of ceramide in the receptor-bearing cell. We used the A498 human kidney cell line, which expressed functional receptors for P and type 1 fimbriae and secreted higher levels of interleukin (IL)-6 when exposed to the fimbriated strains than to isogenic nonfimbriated controls. P-fimbriated E. coli caused the release of ceramide and increased the phosphorylation of ceramide to ceramide 1-phosphate. The IL-6 response to P-fimbriated E. coli was reduced by inhibitors of serine/threonine kinases but not by other protein kinase inhibitors. In contrast, ceramide levels were not influenced by type 1-fimbriated E. coli, and the IL-6 response was insensitive to the serine/threonine kinase inhibitors. These results demonstrate that the ceramide-signaling pathway is activated by P-fimbriated E. coli, and that the receptor specificity of the P fimbriae influences this process. We propose that this activation pathway contributes to the cytokine induction by P-fimbriated E. coli in epithelial cells.


2017 ◽  
Vol 474 (8) ◽  
pp. 1395-1416 ◽  
Author(s):  
Cora Lilia Alvarez ◽  
Gerardo Corradi ◽  
Natalia Lauri ◽  
Irene Marginedas-Freixa ◽  
María Florencia Leal Denis ◽  
...  

We studied the kinetics of extracellular ATP (ATPe) in Escherichia coli and their outer membrane vesicles (OMVs) stimulated with amphipatic peptides melittin (MEL) and mastoparan 7 (MST7). Real-time luminometry was used to measure ATPe kinetics, ATP release, and ATPase activity. The latter was also determined by following [32P]Pi released from [γ-32P]ATP. E. coli was studied alone, co-incubated with Caco-2 cells, or in rat jejunum segments. In E. coli, the addition of [γ-32P]ATP led to the uptake and subsequent hydrolysis of ATPe. Exposure to peptides caused an acute 3-fold (MST7) and 7-fold (MEL) increase in [ATPe]. In OMVs, ATPase activity increased linearly with [ATPe] (0.1–1 µM). Exposure to MST7 and MEL enhanced ATP release by 3–7 fold, with similar kinetics to that of bacteria. In Caco-2 cells, the addition of ATP to the apical domain led to a steep [ATPe] increase to a maximum, with subsequent ATPase activity. The addition of bacterial suspensions led to a 6–7 fold increase in [ATPe], followed by an acute decrease. In perfused jejunum segments, exposure to E. coli increased luminal ATP 2 fold. ATPe regulation of E. coli depends on the balance between ATPase activity and ATP release. This balance can be altered by OMVs, which display their own capacity to regulate ATPe. E. coli can activate ATP release from Caco-2 cells and intestinal segments, a response which in vivo might lead to intestinal release of ATP from the gut lumen.


2001 ◽  
Vol 69 (5) ◽  
pp. 2838-2846 ◽  
Author(s):  
Nereus W. Gunther ◽  
Virginia Lockatell ◽  
David E. Johnson ◽  
Harry L. T. Mobley

ABSTRACT Escherichia coli is the primary cause of uncomplicated infections of the urinary tract including cystitis. More serious infections, characterized as acute pyelonephritis, can also develop. Type 1 fimbriae of E. coli contribute to virulence in the urinary tract; however, only recently has the expression of the type 1 fimbriae been investigated in vivo using molecular techniques. Transcription of type 1 fimbrial genes is controlled by a promoter that resides on a 314-bp invertible element capable of two orientations. One places the promoter in the ON orientation, allowing for transcription; the other places the promoter in the OFF orientation, preventing transcription. A PCR-based assay was developed to measure the orientation of the invertible element during an experimental urinary tract infection in mice. Using this assay, it was found that the percentage of the population ON in urine samples correlated with the respective CFU per gram of bladder (P = 0.0006) but not with CFU per gram of kidney (P > 0.069). Cystitis isolates present in the urine of mice during the course of infection had a higher percentage of their invertible elements in the ON orientation than did pyelonephritis isolates (85 and 34%, respectively, at 24 h; P < 0.0001). In general, cystitis isolates, unlike pyelonephritis isolates, were more likely to maintain their invertible elements in the ON orientation for the entire period of infection. E. coli cells expressing type 1 fimbriae, expelled in urine, were shown by scanning electron microscopy to be densely packed on the surface of uroepithelial cells. These results suggest that expression of type 1 fimbriae is more critical for cystitis strains than for pyelonephritis strains in the early stages of an infection during bladder colonization.


2004 ◽  
Vol 72 (8) ◽  
pp. 4570-4578 ◽  
Author(s):  
Robert Blomgran ◽  
Limin Zheng ◽  
Olle Stendahl

ABSTRACT Type 1 fimbriae are the most commonly expressed virulence factor on uropathogenic Escherichia coli. In addition to promoting avid bacterial adherence to the uroepithelium and enabling colonization, type 1 fimbriae recruit neutrophils to the urinary tract as an early inflammatory response. Using clinical isolates of type 1 fimbriated E. coli and an isogenic type 1 fimbria-negative mutant (CN1016) lacking the FimH adhesin, we investigated if these strains could modulate apoptosis in human neutrophils. We found that E. coli expressing type 1 fimbriae interacted with neutrophils in a mannose- and lipopolysaccharide (LPS)-dependent manner, leading to apoptosis which was triggered by the intracellular generation of reactive oxygen species. This induced neutrophil apoptosis was abolished by blocking FimH-mediated attachment, by inhibiting NADPH oxidase activation, or by neutralizing LPS. In contrast, CN1016, which did not adhere to or activate the respiratory burst of neutrophils, delayed the spontaneous apoptosis in an LPS-dependent manner. This delayed apoptosis could be mimicked by adding purified LPS and was also observed by using fimbriated bacteria in the presence of d-mannose. These results suggest that LPS is required for E. coli to exert both pro- and antiapoptotic effects on neutrophils and that the difference in LPS presentation (i.e., with or without fimbriae) determines the outcome. The present study showed that there is a fine-tuned balance between type 1 fimbria-induced and LPS-mediated delay of apoptosis in human neutrophils, in which altered fimbrial expression on uropathogenic E. coli determines the neutrophil survival and the subsequent inflammation during urinary tract infections.


Author(s):  
Christin Bartlitz ◽  
Rafał Kolenda ◽  
Jarosław Chilimoniuk ◽  
Krzysztof Grzymajło ◽  
Stefan Rödiger ◽  
...  

Pathogenic bacteria, such as enteropathogenic (EPEC) and enterotoxigenic Escherichia coli (ETEC), cause diarrhea in mammals. In particular, E. coli colonize and infect the gastrointestinal tract via type 1 fimbriae (T1F). Here the major zymogen granule membrane glycoprotein 2 (GP2) acts as host cell receptor. GP2 is also secreted by the pancreas and various mucous glands, interacting with luminal type 1 fimbriae-positive E. coli . It is unknown whether GP2 isoforms demonstrate specific E. coli pathotype binding. In this study, we investigated interactions of human, porcine and bovine EPEC, ETEC as well as commensal E. coli isolates with human, porcine and bovine GP2. We first defined pathotype- and host-associated FimH variants. Secondly, we could prove that GP2 isoforms bound to FimH variants to varying degrees. However, the GP2-FimH interactions did not seem to be influenced by the host specificity of E. coli . In contrast, soluble GP2 affected ETEC infection and phagocytosis rates of macrophages. Pre-incubation of ETEC pathotype with GP2 reduced infection of cell lines. Furthermore, pre-incubation of E. coli with GP2 improved the phagocytosis rate of macrophages. Our findings suggest that GP2 plays a role in the defense against E. coli infection and in the corresponding host immune response. IMPORTANCE Infection by pathogenic bacteria such as certain Escherichia coli pathotypes results in diarrhea in mammals. Pathogens, including zoonotic agents, can infect different hosts or show host-specificity. There are Escherichia coli strains which are frequently transmitted between humans and animals, whereas other Escherichia coli strains tend to colonize only one host. This host-specificity is still not fully understood. We show that glycoprotein 2 is a selective receptor for particular Escherichia coli strains or variants of the adhesin FimH but not a selector for a species-specific Escherichia coli group. We demonstrate that GP2 is involved in the regulation of colonization and infection and thus represents a molecule of interest for the prevention or treatment of disease.


2021 ◽  
Author(s):  
Mari YOSHIDA ◽  
Stanislas THIRIET-RUPERT ◽  
Leonie MAYER ◽  
Christophe BELOIN ◽  
Jean-Marc GHIGO

Bacterial interactions with surfaces rely on the coordinated expression and interplay of surface exposed adhesion factors. However, how bacteria dynamically modulate their vast repertoire of adhesins to achieve surface colonization is not yet well-understood. We used experimental evolution and positive selection for improved adhesion to investigate how an initially poorly adherent Escherichia coli strain increased its adhesion capacities to abiotic surfaces. We showed that all identified evolved clones acquired mutations located almost exclusively in the lectin domain of fimH, the gene coding for the alpha-D-mannose-specific tip adhesin of type 1 fimbriae. While most of these fimH mutants showed reduced mannose-binding ability, they all displayed enhanced binding to abiotic surfaces, indicating a trade-off between FimH-mediated specific and non-specific adhesion properties. Several of the identified mutations were already reported in FimH lectin domain of pathogenic and environmental E. coli, suggesting that, beyond patho-adaptation, FimH microevolution favoring non-specific surface adhesion could constitute a selective advantage for natural E. coli isolates. Consistently, although E. coli deleted for the fim operon still evolves an increased adhesion capacity, mutants selected in the ∆fim background are outcompeted by fimH mutants revealing clonal interference for adhesion. Our study therefore provides insights into the plasticity of E. coli adhesion potential and shows that evolution of type 1 fimbriae is a major driver of the adaptation of natural E. coli to colonization.


2001 ◽  
Vol 8 (3) ◽  
pp. 489-495 ◽  
Author(s):  
Ken-Ichiro Iida ◽  
Yoshimitsu Mizunoe ◽  
Sun Nyunt Wai ◽  
Shin-Ichi Yoshida

ABSTRACT Type 1 fimbriae can be expressed by most Escherichia coli strains and mediate mannose-sensitive (MS) adherence to mammalian epithelial cells. However, the role of type 1 fimbriae in enteric pathogenesis has been unclear. Expression of type 1 fimbriae inE. coli is phase variable and is associated with the inversion of a short DNA element (fim switch). Forty-six strains of diarrheagenic E. coli were examined for the expression of type 1 fimbriae. Only four of these strains were originally type 1 fimbriated. Seventeen strains, originally nonfimbriated, expressed type 1 fimbriae in association with off-to-on inversion of the fim switch, after serial passages in static culture. The switching frequencies of these strains, from fimbriate to nonfimbriate, were greater than that of the laboratory strain E. coli K-12. None of the 16 strains of serovar O157:H7 or O157:H− expressed type 1 fimbriae after serial passages in static culture. The nucleotide sequence analysis of thefim switch region revealed that all of the O157:H7 and O157:H− strains had a 16-bp deletion in the invertible element, and the fim switch was locked in the “off” orientation. The results suggest that expression of type 1 fimbriae may be regulated differently in different E. coli pathogens causing enteric infections.


2006 ◽  
Vol 74 (10) ◽  
pp. 5609-5616 ◽  
Author(s):  
Ching-Hao Teng ◽  
Yi Xie ◽  
Sooan Shin ◽  
Francescopaolo Di Cello ◽  
Maneesh Paul-Satyaseela ◽  
...  

ABSTRACT We have previously shown that outer membrane protein A (OmpA) and type 1 fimbriae are the bacterial determinants involved in Escherichia coli K1 binding to human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. In investigating the role of OmpA in E. coli K1 binding to HBMEC, we showed for the first time that ompA deletion decreased the expression of type 1 fimbriae in E. coli K1. Decreased expression of type 1 fimbriae in the ompA deletion mutant was largely the result of driving the fim promoter toward the type 1 fimbrial phase-OFF orientation. mRNA levels of fimB and fimE were found to be decreased with the OmpA mutant compared to the parent strain. Of interest, the ompA deletion further decreased the abilities of E. coli K1 to bind to and invade HBMEC under the conditions of fixing type 1 fimbria expression in the phase-ON or phase-OFF status. These findings suggest that the decreased ability of the OmpA mutant to interact with HBMEC is not entirely due to its decreased type 1 fimbrial expression and that OmpA and type 1 fimbriae facilitate the interaction of E. coli K1 with HBMEC at least in an additive manner.


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