In vitro and in vivo adherence of uropathogenic Escherichia coli strains

Twenty-eight Escherichia coli strains isolated from the urine of patients with urinary tract infections were assayed for fimbrial type, in vitro capacity to agglutinate guinea pig red blood cells, and in vivo adherence to rat bladder uroepithelium. A direct correlation was found between hemagglutinating capacity and in vivo adherence. Strains with both Type 1 and P fimbriae showed the greatest adherence in vivo. Of the 28 strains, seven did not manifest either Type 1 or P fimbriae but agglutinated red blood cells and did adhere in vivo. In studies on bacterial adherence and urinary tract infections, both in vivo and in vitro studies may contribute to understanding the relevance of bacterial adhesins in initiating urinary tract infections.     

Receptors for Escherichia coli adhesins in the genitourinary tract in a non-human primate

OBJECTIVE: To study the expression of receptors allowing adhesin-mediated binding of Escherichia coli to urogenital tissues ranging from the kidney to the vagina in cynomolgus monkeys using an in situ assay. MATERIAL AND METHODS: Receptors specific for four relevant adhesins were investigated: PapG and PrsG of P-fimbriae binding to gal-alpha(1-4)gal glycosphingolipids (preferentially globoside and the Forssman antigen, respectively): and two variants of FimH of type 1 fimbriae, one binding to monomannose/trimannose and the other to trimannose only. To ascertain the specificity of the observed bindings we used adhesion inhibition by receptor analogues as well as E. coli adhesin knockout mutants. RESULTS: The distributions of PapG and FimH receptors in monkey tissues showed great similarities to available data in humans. Whilst monomannose receptors were expressed on the surface epithelium in both the monkey bladder and ureter, trimannose receptors were not. The different distribution of FimH isoreceptors and the heterogeneity of FimH adhesin variants among E. coli may explain contradictory earlier findings in type 1 fimbriae-mediated adhesion to the human bladder and to renal tissues. We also found evidence of a hitherto unknown type of host-aggressor interaction on vaginal and urethral mucosa, which was not discovered until type 1 fimbriae had been eliminated. CONCLUSIONS: A precise molecular fit between host receptors and bacterial lectins is important in infectious pathogenesis. We conclude that urinary tract infection in the cynomolgus monkey is a relevant model of the human disease because of the similarity in the expression of receptors for E. coli adhesins on epithelial surfaces in the two species.     

Hepatocyte growth factor alters renal epithelial cell susceptibility to uropathogenic Escherichia coli.

The urinary tract is frequently the source of Escherichia coli bacteremia. Bacteria from the urinary tract must cross an epithelial layer to enter the bloodstream. Hepatocyte growth factor (HGF) alters the polarity of Madin-Darby canine kidney (MDCK) epithelial cells. The role of cell polarity in determining renal epithelial resistance to Escherichia coli invasion is not well known. A model of polarized and HGF-treated MDCK epithelial cells grown on filters was used to study the role of epithelial cell polarity during the interaction of nonvirulent (XL1-Blue) and uropathogenic (J96) strains of Escherichia coli with renal epithelium. Basolateral exposure of MDCK cells to J96, but not XL1-Blue, resulted in loss of transepithelial resistance (TER), which was due to epithelial cytotoxicity and not degradation of epithelial junctional proteins by bacterial proteases. Apical exposure to both J96 and XL1-Blue did not alter TER. Pretreatment of polarized MDCK cell monolayers with HGF renders the cells sensitive to loss of TER and cytotoxicity by apical exposure to J96. Analysis by confocal microscopy demonstrated that HGF treatment of MDCK cell monolayers also greatly enhances adherence of J96 to the apical surface of the cell monolayer. These data demonstrate that the basolateral surface of polarized epithelia is more susceptible to J96 cytotoxicity. The data also support the hypothesis that processes that alter epithelial cell polarity increase sensitivity of epithelia to bacterial injury and adherence from the apical compartment.     

fimH基因对泌尿道致病性大肠埃希菌1型菌毛粘附功能影响的初步探讨

目的 研究fimH基因对泌尿道致病性大肠埃希菌(UPEC)1型菌毛粘附功能的影响,比较1型菌毛粘附阳性与阴性菌株的基因变化.方法 对天津地区三家三级甲等医院(天津医科大学第二医院、天津市第一中心医院、天津市儿童医院)2012年1月至2013年1月非植入导尿管患者的尿液样本分离非重复感染大肠埃希菌171株进行研究,通过PCR检测fimH基因携带情况,酵母细胞粘附实验检测1型菌毛的粘附情况.针对fimH基因进行RT-PCR实验,消除转录对粘附作用的影响.采用常规x2检验和Yates校正x2检验比较fimH基因转录粘附阴性组与阳性组间fimH基因序列的改变.结果 天津地区UPEC菌株fimH基因携带率为83％,1型菌毛粘附率为57％,粘附阳性菌株均携带fimH基因.因fimH基因未转录导致粘附阴性的菌株占18％.第51位氨基酸位点粘附阳性组较阴性组更易发生突变(x2=6.64,P=0.010);第190位与第219位氨基酸位点于粘附阴性组各有6株菌和7株菌发生突变,而阳性组未见突变(x2=4.69和5.87,P值均＜0.05);粘附阴性组其余23株菌株无法用单核苷酸多态性改变解释其粘附阴性.结论 fimH基因的突变与缺失可以影响UPEC菌株1型菌毛粘附功能,除了转录调控外,还发现了可能引起1型菌毛粘附功能改变的3个关键位点;粘附过程中除fimH基因这一关键因素外,其他基因可能也会影响1型菌毛的粘附功能.     

The role of laparoscopy in the management of acute small-bowel obstruction: a review of over 2,000 cases

Background  

Adhesive small-bowel obstruction (SBO) contributes significantly to emergency surgical workload. Laparotomy remains the standard approach. Despite published reports with high success rates and low morbidity, acute SBO is still considered by many a relative contraindication to laparoscopy. Our aim was to review the available literature and define important outcomes such as feasibility, safety, iatrogenic bowel injury, and benefits to patients with acute SBO who are approached laparoscopically.     

Distinct isolates of uropathogenic Escherichia coli differentially affect human sperm parameters in vitro

Sperm motility and vitality are decreased in male genital tract infection. Uropathogenic Escherichia coli (UPEC) are frequently associated with sperm parameter loss, but there are no reports to date regarding the effects of different E. coli isolates on human spermatozoa. The aim of this work was to compare the effect in vitro of different E. coli isolates on human sperm parameters. Normal spermatozoa were incubated with E. coli isolated from nine men with urinary tract infection. After 1 h of incubation, sperm motility, vitality and mitochondrial membrane potential (ΔΨm) were measured. The E. coli isolates were serotyped with specific antisera. Sperm motility was decreased with five of nine E. coli isolates. Two UPEC were typed as O6 strains, and they did not decrease sperm motility in the same experimental conditions as the other five isolates, despite the described high pathogenicity of the O6 strain in urogenital infections. Neither UPEC analysed affected vitality or ΔΨm. UPEC isolates were shown to be heterogeneous in their effects, suggesting the need to characterise the pattern defining the pathogenicity of E. coli on human spermatozoa.     

Biofilm formation in uropathogenic Escherichia coli strains: relationship with prostatitis, urovirulence factors and antimicrobial resistance

PURPOSE: Escherichia coli strains are the most frequent cause of urinary tract infections. Biofilm formation allows the strains to persist a long time in the genitourinary tract and interfere with bacterial eradication. We determined the possible relationships between the different urinary tract infections, and in vitro biofilm formation, the presence of urovirulence factors and nalidixic acid resistance. MATERIALS AND METHODS: A total of 151 E. coli strains collected from patients with cystitis (44 strains), pyelonephritis (75) and prostatitis (32) were analyzed for in vitro biofilm formation, the phylogenetic group, the presence of several urovirulence factors and resistance to nalidixic acid. RESULTS: E. coli strains causing prostatitis produced biofilm in vitro more frequently than those causing other urinary tract infections and had a higher frequency of hemolysin (p = 0.03 and 0.0002, respectively). However, only hemolysin was independently associated with prostatitis. On the other hand, strains forming biofilm presented a significantly higher frequency of hemolysin and type 1 fimbriae expression. CONCLUSIONS: Although hemolysin is the main virulence factor by which E. coli causes acute prostatitis, the association between hemolysin and biofilm formation may result in increased ability of E. coli strains to persist in the prostate.     

Medicinal plants extracts affect virulence factors expression and biofilm formation by the uropathogenic Escherichia coli

Medicinal plants are an important source for the therapeutic remedies of various diseases including urinary tract infections. This prompted us to perform research in this area. We decided to focus on medicinal plants species used in urinary tract infections prevention. The aim of our study was to determine the influence of Betula pendula, Equisetum arvense, Herniaria glabra, Galium odoratum, Urtica dioica, and Vaccinium vitis-idaea extracts on bacterial survival and virulence factors involved in tissue colonization and biofilm formation of the uropathogenic Escherichia coli rods. Qualitative and quantitative analysis of plant extracts were performed. Antimicrobial assay relied on the estimation of the colony forming unit number. Hydrophobicity of cells was established by salt aggregation test. Using motility agar, the ability of bacteria to move was examined. The erythrocyte hemagglutination test was used for fimbriae P screening. Curli expression was determined using YESCA agar supplemented with congo red. Quantification of biofilm formation was carried out using a microtiter plate assay and a spectrophotometric method. The results of the study indicate significant differences between investigated extracts in their antimicrobial activities. The extracts of H. glabra and V. vitis-idaea showed the highest growth-inhibitory effects (p?<?0.05). Surface hydrophobicity of autoaggregating E. coli strain changed after exposure to all plant extracts, except V. vitis-idaea (p?>?0.05). The B. pendula and U. dioica extracts significantly reduced the motility of the E. coli rods (p?<?0.05). All the extracts exhibited the anti-biofilm activity.     

Distribution of afaE adhesins in Escherichia coli isolated from Japanese patients with urinary tract infection

PURPOSE: Afimbrial adhesin is known to be one of the most prevalent virulence factors in uropathogenic Escherichia coli. A recent report showed that the new subtype afaE8 predominated in afa positive isolates from patients with pyelonephritis (55.6%), suggesting that this subtype may be an important factor in ascending urinary tract infections. MATERIALS AND METHODS: A total of 457 E. coli strains consisting, of 194, 76 and 107 isolates from patients with cystitis, pyelonephritis and prostatitis, respectively, and 80 isolates from the rectal flora of healthy individuals were subjected to polymerase chain reaction to determine the afa operon as well as afaE subtypes.RESULTS: We identified 32 afa positive isolates of 377 strains (8.5%) and 2 of 80 strains (2.5%) from urinary tract infection isolates and normal flora, respectively. When afaE subtypes were determined, the afaE3 subtype predominated in afa positive isolates from cystitis (64.7%), pyelonephritis (66.7%) and prostatitis (50%). However, the afaE8 subtype was absent from urinary tract infection isolates, while only 1 isolate from the stool of a healthy adult harbored this subtype. CONCLUSIONS: Our data show that the afaE3 subtype predominated in pyelonephritis as well as in other urinary tract infections, indicating that the afa gene may be important in urinary tract infection. However, the distribution of afaE subtypes may be diverse in different areas of the world.     

Innate immunity of surfactant protein A and D in urinary tract infection with uropathogenic Escherichia coli

Objective To investigate the role of surfactant protein (SP) - A and SP - D in urinary tract infection mouse model, and evaluate the effects of SP-A and SP-D absence on urinary tract infection. Methods SP-A and SP-D double knockout (SP-A/D KO) mice were made. SP-A/D KO and wild-type (WT) C57BL/6 female mice were used for this study. The expression of SP-A and SP-D in kidney was detected by immunohistochemistry (IHC). The levels of p - p38 and p38 protein in kidneys were measured by Western blotting. Uropathogenic Escherichia coli or buffer was delivered into the bladder of female mice. At 24 and 48 h after inoculation, CFU of Escherichia coli in the kidney and urine of the treated and control mice were measured. Histological, cellular and molecular analysis were performed by several methods of H/E staining, IHC and Western blotting. The effects of SP-A and SP-D on bacterial growth were studied in vitro. Results SP-A and SP-D in kidney were located in the proximal tubules and collecting tubules. Compared with WT mice, infected SP - A/D KO mice with UPEC had higher CFU in kidneys and urine at 24 h and 48 h, increased inflammatory cells infiltration in kidneys（P＜0.05）. Compared with WT mice, SP - A/D KO mice had higher p38 MAPK phosphorylation levels in kidneys（P＜0.05）. Growth of Escherichia coli was greatly inhibited by both SP-A and SP-D（P＜0.05）. Conclusions Both SP-A and SP-D are expressed in kidney. SP-A and SP-D can attenuate UTI induced by UPEC which may be through inhibiting bacterial growth and modulating renal inflammation.     

Subtyping of uropathogenic Escherichia coli according to the pathogenicity island encoding uropathogenic-specific protein: Comparison with phylogenetic groups

BACKGROUND: Phylogenetic analysis has been used widely to characterize extraintestinal pathogenic Escherichia coli in molecular epidemiological studies. We have recently reported a putative pathogenicity island (PAI), carrying uropathogenic-specific protein (usp) and a unique mosaic structure of small open reading frames following usp, providing four subtypes of PAIusp classified from their sequential patterns. METHODS: A total of 427 E. coli isolates from uncomplicated urinary tract infections (194 cystitis, 76 pyelonephritis, and 107 prostatitis) and 50 fecal isolates were examined for phylogenetic grouping and PAIusp subtyping as well as the prevalence of virulence factors (VF) and O serogroups. RESULTS: Both phylogenetic group B2 and usp-positive strains were equally predominant in cystitis, pyelonephritis and prostatitis (B2, 80.9%, 86.8%, and 86.9%; usp, 79.4%, 93.4%, and 88.8%, respectively). Furthermore, each PAIusp subtype was shown to be closely associated with several VF genes as well as several common O serogroups of uropathogenic E. coli. CONCLUSIONS: In molecular epidemiological studies, PAIusp subtyping will provide additional informative findings of E. coli strains belonging to phylogenetic group B2.     

Organ distribution of radiolabeled enteric Escherichia coli during and after hemorrhagic shock.

Translocation of intestinal bacteria to the blood during hemorrhagic shock (HS) has been confirmed in rats and humans. The current study was designed to trace the path of translocated intestinal bacteria in a murine HS model. Thirty-one rats were gavaged with 1,000,000 counts of viable 14C oleic acid-labeled Escherichia coli. Forty-eight hours later the animals were bled to 30 mmHg until either 80% of their maximal shed blood was returned or 5 hours of shock had elapsed and they were resuscitated with Ringer's lactate as previously described. Control animals were cannulated but not shocked. Eight rats immediately after shock and resuscitation, 6 rats 24 hours after shock, 3 rats 48 hours after shock, and 4 animals that died in shock had their heart, lung, liver, spleen, kidney, and serum harvested, cultured, and radioactive content measured. Translocated enteric bacteria are found primarily in the lung immediately after shock with redistribution to the liver and kidney 24 hours later. Animals surviving to 48 hours were capable of eliminating the majority of the bacteria from their major organ systems. Positive cultures for E. coli were also found in the blood, lung, liver, and kidney. We speculate that the inflammatory response stimulated by the bacteria in these organs may contribute to the multiple-organ failure syndrome seen after HS.     

Variable adherence of uropathogenic Escherichia coli to epithelial cells from women with recurrent urinary tract infection

The adherence of 74 Escherichia coli strains to vaginal and buccal epithelial cells from women with recurrent urinary tract infections was studied. The strains were isolated from the urine, vaginal introitus or anal mucosa of women with recurrent bacteriuria. Vaginal and anal isolates were judged to be associated with urinary tract infection if they had the same biotype and serotype as the strain isolated subsequently from the urine. Adherence levels of urinary and anal isolates, and vaginal isolates associated with urinary tract infection were similar for vaginal and buccal cells. Adherence of vaginal isolates not associated with urinary tract infection was significantly lower than adherence of urinary isolates for vaginal (p less than 0.001) and buccal (p less than 0.005) epithelial cells. A positive nonlinear correlation between vaginal and buccal adherence was observed for urinary (r equals 0.87, p less than 0.0001), vaginal (r equals 0.70, p less than 0.0005) and anal (r equals 0.32, p equals 0.047) isolates. Strains of O-serogroups commonly and less commonly associated with bacteriuria had similar adherence. The results suggest that adherence of vaginal isolates is associated with the ability to cause urinary tract infections. The strong correlation between vaginal and buccal cell receptivity suggests that susceptibility to such infections may be controlled by genotypic traits.