Establishment and Characterization of UTI and CAUTI in a Mouse Model

Urinary tract infections (UTI) are highly prevalent, a significant cause of morbidity and are increasingly resistant to treatment with antibiotics. Females are disproportionately afflicted by UTI: 50% of all women will have a UTI in their lifetime. Additionally, 20-40% of these women who have an initial UTI will suffer a recurrence with some suffering frequent recurrences with serious deterioration in the quality of life, pain and discomfort, disruption of daily activities, increased healthcare costs, and few treatment options other than long-term antibiotic prophylaxis. Uropathogenic Escherichia coli (UPEC) is the primary causative agent of community acquired UTI. Catheter-associated UTI (CAUTI) is the most common hospital acquired infection accounting for a million occurrences in the US annually and dramatic healthcare costs. While UPEC is also the primary cause of CAUTI, other causative agents are of increased significance including Enterococcus faecalis. Here we utilize two well-established mouse models that recapitulate many of the clinical characteristics of these human diseases. For UTI, a C3H/HeN model recapitulates many of the features of UPEC virulence observed in humans including host responses, IBC formation and filamentation. For CAUTI, a model using C57BL/6 mice, which retain catheter bladder implants, has been shown to be susceptible to E. faecalis bladder infection. These representative models are being used to gain striking new insights into the pathogenesis of UTI disease, which is leading to the development of novel therapeutics and management or prevention strategies.     

Uropathogenic Escherichia coli Superinfection Enhances the Severity of Mouse Bladder Infection

Urinary tract infections (UTIs) afflict over 9 million women in America every year, often necessitating long-term prophylactic antibiotics. One risk factor for UTI is frequent sexual intercourse, which dramatically increases the risk of UTI. The mechanism behind this increased risk is unknown; however, bacteriuria increases immediately after sexual intercourse episodes, suggesting that physical manipulation introduces periurethral flora into the urinary tract. In this paper, we investigated whether superinfection (repeat introduction of bacteria) resulted in increased risk of severe UTI, manifesting as persistent bacteriuria, high titer bladder bacterial burdens and chronic inflammation, an outcome referred to as chronic cystitis. Chronic cystitis represents unchecked luminal bacterial replication and is defined histologically by urothelial hyperplasia and submucosal lymphoid aggregates, a histological pattern similar to that seen in humans suffering chronic UTI. C57BL/6J mice are resistant to chronic cystitis after a single infection; however, they developed persistent bacteriuria and chronic cystitis when superinfected 24 hours apart. Elevated levels of interleukin-6 (IL-6), keratinocyte cytokine (KC/CXCL1), and granulocyte colony-stimulating factor (G-CSF) in the serum of C57BL/6J mice prior to the second infection predicted the development of chronic cystitis. These same cytokines have been found to precede chronic cystitis in singly infected C3H/HeN mice. Furthermore, inoculating C3H/HeN mice twice within a six-hour period doubled the proportion of mice that developed chronic cystitis. Intracellular bacterial replication, regulated hemolysin (HlyA) expression, and caspase 1/11 activation were essential for this increase. Microarrays conducted at four weeks post inoculation in both mouse strains revealed upregulation of IL-1 and antimicrobial peptides during chronic cystitis. These data suggest a mechanism by which caspase-1/11 activation and IL-1 secretion could predispose certain women to recurrent UTI after frequent intercourse, a predisposition predictable by several serum biomarkers in two murine models.     

Chromosomal and plasmid encoded drug resistances of a <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> UTI 2 strain isolated from urine of a post-operative patient

The multi drug resistance Klebsiella pneumoniae in urinary tract infection is a common clinical problem in developing country like India. Use of random antibiotics, resulting multi drug resistance development, creates difficulties for treatment. In our present study, we investigated a strain of Klebsiella pneumoniae UTI 2 with multiple drug resistance, which was isolated from urine of a post operative woman patient (50 years) suffering from urinary tract infection with high fever. This strain is resistant to 36 antibiotics and sensitive to cefotaxime (Ce) and imipenem (I). After curing of plasmids, we observed that, 55% of drug resistant loci of K. pneumoniae UTI 2 are chromosomal and 40% are plasmid encoded. The organism is sensitive to 5% of drugs tested, i.e. Ce and I. This study contributes to understand the drug resistance of Klebsiella pneumoniae, which will enable better clinical management of catheter-associated urinary tract infections, a major health problem.     

2000-2002年浙江地区尿路感染病原菌的变迁及耐药性分析

对 2 0 0 0年初至 2 0 0 2年底 6 30 6例浙江地区疑似尿路感染 (UTI)患者尿液标本进行了细菌及真菌分离培养和药敏试验。上述标本中 ,革兰阳性菌、革兰阴性菌和真菌的检出率分别为 6 .5 % ,13.6 %和10 .1% ,其中真菌阳性检出率超过革兰阳性菌居第二位。粪肠球菌和白假丝酵母菌分别成为UTI的优势革兰阳性菌和真菌。所试验的革兰阳性菌、革兰阴性菌和真菌分别对亚胺培南、万古霉素、制霉菌素的耐药率最低。不同细菌耐药性有较大差异 ,多重耐药在表皮葡萄球菌及多数受试的革兰阴性菌中为普遍现象。上述实验结果提示 ,近年浙江地区UTI病原菌的种类已发生明显的变迁 ,耐药性也日趋严重。     

Evaluation of Proteus mirabilis structural fimbrial proteins as antigens against urinary tract infections

Proteus mirabilis is a common cause of urinary tract infection (UTI) and produce several types of different fimbriae, including mannose-resistant/Proteus-like fimbriae, uroepithelial cell adhesin (UCA), and P. mirabilis fimbriae (PMF). Different authors have related these fimbriae with different aspects of P. mirabilis pathogenesis, although the precise role of fimbriae in UTI has not yet been elucidated. In this work we expressed and purified recombinant structural fimbrial proteins of these fimbriae (MrpA, UcaA, and PmfA) and assessed their role as protective antigens using an ascending and a haematogenous model of UTI in the mouse. MrpA protected subcutaneously immunised mice in both models, suggesting that it could be taken into account as a promising vaccine candidate against P. mirabilis UTI. UcaA could also be an interesting subunit to be studied although it only protected mice that were challenged intravenously. All subunits elicited a strong specific serum IgG response but there was no significant correlation between antibody levels and protection. Only PmfA-immunised mice elicited a significant urinary antibody response but this protein was unable to confer protection against P. mirabilis experimental challenges. These results may contribute to the development of vaccines against P. mirabilis, an important cause of complicated UTI.     

Maternal urinary tract infections and selected cardiovascular malformations

BACKGROUND: In a population‐based case‐control study, we investigated the association between congenital cardiovascular malformations (CVMs) and maternal urinary tract infections (UTIs). METHODS: Within the National Birth Defects Prevention Study, 3,690 women who had singleton livebirths with nonsyndromic CVMs, and 4,760 women who had infants without birth defects were identified. Affected infants had: conotruncal, septal, anomalous pulmonary venous return, atrioventricular septal defects, or left‐ or right‐sided obstructive heart defects. Mothers had a UTI if they reported having at least one infection during the first trimester. Adjusted ORs and 95% CIs were computed to determine the association between CVMs and UTIs. Stratified analyses were conducted to investigate if sulfonamide use and/or fever modified the effect between CVMs and UTIs. RESULTS: Women who had offspring with either left ventricular outflow tract obstructive defects or atrioventricular septal defects were more likely than controls to report a UTI. These associations remained among women who did not have fever or used sulfonamides. Maternal use of sulfonamides during the UTI did not appear to modify the relationship between CVM subtypes and maternal UTIs. CONCLUSIONS: In the National Birth Defects Prevention Study there was little evidence to support an association between CVMs and UTIs during the first trimester of pregnancy. Associations between left ventricular outflow tract obstructive defects and maternal UTI as well as between atrioventricular septal defects and maternal UTI were found. Our findings, while not conclusive, suggest that the possible association between maternal UTI and CVMs should be investigated further. Birth Defects Research (Part A), 2008. © 2008 Wiley‐Liss, Inc.     

Enterococcus faecalis: specific and non-specific interactions with human polymorphonuclear leukocytes

In previous studies we have demonstrated that the ability of Enterococcus faecalis to adhere to and to be internalized in human urinary tract epithelial cells, Girardi Heart cells and human polymorphonuclear leukocytes (PMNs), was dependent on whether the strain had been isolated from urinary tract infections (UTI) or endocarditis (EN) respectively. These properties were further modified by growth of the organism in human serum. In the present report, using competition assays we show that adhesins containing a D-glucose moiety play a role in mediating the interactions between human PMNs and E. faecalis strains isolated from UTI and grown in brain-heart infusion broth (BHIB). On the other hand, adhesins containing both D-glucose and D-galactose moieties were involved in the interactions between PMNs and serum grown UTI isolates or EN isolates grown in either BHIB or human serum. Moreover, the impairment in the association between both UTI and EN strains after growth in serum appears to be at least partially related to a decrease in enterococcal surface hydrophobicity.     

Asymptomatic Bacteriuria Escherichia coli Are Live Biotherapeutics for UTI

Urinary tract infections (UTI) account for approximately 8 million clinic visits annually with symptoms that include acute pelvic pain, dysuria, and irritative voiding. Empiric UTI management with antimicrobials is complicated by increasing antimicrobial resistance among uropathogens, but live biotherapeutics products (LBPs), such as asymptomatic bacteriuria (ASB) strains of E. coli, offer the potential to circumvent antimicrobial resistance. Here we evaluated ASB E. coli as LBPs, relative to ciprofloxacin, for efficacy against infection and visceral pain in a murine UTI model. Visceral pain was quantified as tactile allodynia of the pelvic region in response to mechanical stimulation with von Frey filaments. Whereas ciprofloxacin promoted clearance of uropathogenic E. coli (UPEC), it did not reduce pelvic tactile allodynia, a measure of visceral pain. In contrast, ASB E. coli administered intravesically or intravaginally provided comparable reduction of allodynia similar to intravesical lidocaine. Moreover, ASB E. coli were similarly effective against UTI allodynia induced by Proteus mirabilis, Enterococccus faecalis and Klebsiella pneumoniae. Therefore, ASB E. coli have anti-infective activity comparable to the current standard of care yet also provide superior analgesia. These studies suggest that ASB E. coli represent novel LBPs for UTI symptoms.     

女性糖尿病患者合并尿路感染大肠埃希菌耐药性分析

目的 回顾性分析女性糖尿病(DM)合并尿路感染( UTI)大肠埃希菌的耐药情况及产超广谱β-内酰胺酶(ESBLs)的发生率,以指导临床合理选择抗菌药物.方法 对近4年在浙江大学医学院附属第二医院确诊DM合并UTI女性患者的中段尿标本中分离出的95株大肠埃希菌进行耐药性分析,用纸片扩散法表型确证试验检测ESBLs,以女性非糖尿病患者为对照组,并以年份进行分组分析.结果 95株大肠埃希菌ESBLs阳性率为40.0％,明显高于对照组,糖尿病组对氨苄西林、环丙沙星、左氧氟沙星耐药率较高,均＞60.0％,对环丙沙星、左氧氟沙星、头孢曲松、头孢唑林、头孢吡肟、头孢呋辛耐药率明显高于对照组,早期组与近期组的产ESBLs率及耐药率差异无统计学意义.结论 女性糖尿病伴尿路感染大肠埃希菌对多种抗菌药物的耐药率较高,临床应根据药敏试验结果合理使用抗菌药物.     

Antibacterial effects of Tungsten nanoparticles on the Escherichia coli strains isolated from catheterized urinary tract infection (UTI) cases and Staphylococcus aureus

A significant proportion of all incidents of nosocomial infections in acute-care hospitals is due to contaminated catheters. Alternative strategies e.g. antibiotics as well as surface modifications have been devised in an attempt to reduce the incidence of catheter-associated urinary tract infections (CAUTI), but most have proven unsuccessful. Therefore, the race to identify such substances which can combat pathogenic bacteria is ongoing in order to improve the quality of health care. Novel technologies such as the potential use of antiseptic or antimicrobial coatings on catheters hold promise for reducing these infections in the fight against antimicrobial resistance. In this study, the bactericidal activity of newly synthesized tungsten-nanoparticles was tested on clinical multiple drug resistant Escherichia coli isolates from UTI patients with indwelling catheters and Staphylococcus aureus reference strain. The results suggest that the particles tested in this study certainly mediate the inhibition of bacterial growth. We believe that the fabrication of W-NPs on catheters could possibly prevent them from being contaminated by pathogens and hence provide continuous protection of the site. This study is the first of its type testing the antibacterial effects of W-NPs on clinical bacterial isolate from catheterized human UTI case.     

The role of cytotoxic necrotizing factor-1 in colonization and tissue injury in a murine model of urinary tract infection

Cytotoxic necrotizing factor-1 (CNF1) is commonly found in Escherichia coli isolates from patients with urinary tract infection (UTI). To determine whether CNF1 is an important UTI virulence factor we compared the ability of a clinical E. coli UTI isolate and a CNF1-negative mutant of that isolate to colonize and induce histological changes in the urinary tract in a murine model of ascending UTI. We found no evidence that the mutant strain was attenuated.     

Bacterial profile and drug susceptibility pattern of urinary tract infection in pregnant women at University of Gondar Teaching Hospital, Northwest Ethiopia

ABSTRACT: BACKGROUND: Urinary tract infection (UTI) is a common health problem among pregnant women. Proper investigation and prompt treatment are needed to prevent serious life threatening condition and morbidity due to urinary tract infection that can occur in pregnant women. Recent report in Addis Ababa, Ethiopia indicated the prevalence of UTI in pregnant women was 11.6 % and Gram negative bacteria was the predominant isolates and showed multi drug resistance. This study aimed to assess bacterial profile that causes urinary tract infection and their antimicrobial susceptibility pattern among pregnant women visiting antenatal clinic at University of Gondar Teaching Hospital, Northwest Ethiopia. METHODS: A cross-sectional study was conducted at University of Gondar Teaching Hospital from March 22 to April 30, 2011. Mid stream urine samples were collected and inoculated into Cystine Lactose Electrolyte Deficient medium (CLED). Colony counts yielding bacterial growth of 105/ml of urine or more of pure isolates were regarded as significant bacteriuria for infection. Colony from CLED was sub cultured onto MacConkey agar and blood agar plates. Identification was done using cultural characteristics and a series of biochemical tests. A standard method of agar disc diffusion susceptibility testing method was used to determine susceptibility patterns of the isolates. RESULTS: The overall prevalence of UTI in pregnant women was 10.4 %. The predominant bacterial pathogens were Escherichia coli 47.5 % followed by coagulase-negative staphylococci 22.5 %, Staphylococcus aureus 10 %, and Klebsiella pneumoniae 10 %. Gram negative isolates were resulted low susceptibility to co-trimoxazole (51.9 %) and tetracycline (40.7 %) whereas Gram positive showed susceptibility to ceftriaxon (84.6 %) and amoxicillin-clavulanic acid (92.3 %). Multiple drug resistance (resistance to two or more drugs) was observed in 95 % of the isolates. CONCLUSION: Significant bacteriuria was observed in asymptomatic pregnant women. Periodic studies are recommended to check the outcome of asymptomatic bacteriuria and also monitor any changes in the susceptibility patterns of urinary tract pathogens in pregnant women.     

Time-based distribution of Staphylococcus saprophyticus pulsed field gel-electrophoresis clusters in community-acquired urinary tract infections

The epidemiology of urinary tract infections (UTI) by Staphylococcus saprophyticus has not been fully characterised and strain typing methods have not been validated for this agent. To evaluate whether epidemiological relationships exist between clusters of pulsed field gel-electrophoresis (PFGE) genotypes of S. saprophyticus from community-acquired UTI, a cross-sectional surveillance study was conducted in the city of Rio de Janeiro, Brazil. In total, 32 (16%) female patients attending two walk-in clinics were culture-positive for S. saprophyticus. Five PFGE clusters were defined and evaluated against epidemiological data. The PFGE clusters were grouped in time, suggesting the existence of community point sources of S. saprophyticus. From these point sources, S. saprophyticus strains may spread among individuals.     

Cranberry juice for prophylaxis of urinary tract infections – Conclusions from clinical experience and research

Cranberry juice (Vaccinium macrocarpon) is a widely used and recommended North-American folk remedy for prophylaxis of urinary tract infections (UTI). Clinical trials have documented its efficacy in women with recurrent UTI, but so far not in other groups of patients. The composition of effective cranberry products and its dosage in UTI prophylaxis have not been defined. Intriguing experimental research has identified an anti-adhesive mechanism of cranberry juice that prevents docking of bacteria on host tissues. This efficacy mechanism can be traced in patients’ urine following oral intake of cranberry products and appears to be due to proanthocyanidins with an A-type linkage of flavanols. The application of this anti-adhesion mechanism of cranberry-proanthocyandins is currently also investigated in other common diseases of bacterial pathogenesis, for example Helicobacter pylori-associated gastritis and dental caries/periodontal disease. The use of cranberry products appears to be safe and provide additional benefits by anti-oxidant and cholesterol-lowering activity.     

Vitamin D deficiency as a risk factor for urinary tract infection in women at reproductive age

Vitamin D deficiency is a pandemic problem and an ever-increasing issue in human nutrition and health. Vitamin D (serum 25-hydroxyvitamin D) deficiency causes many health problems such as autoimmune diseases, Crohn’s disease, diabetes, inflammation, asthma, hypertension, and cancer. Vitamin D3 (cholecalciferol) deficiency has been documented as a persistent problem among adults, children, and elderly persons in most of the countries. Our main objective of this study was to determine the hypothesis that the vitamin D deficiency among women can lead to them developing frequent urinary tract infections. Vitamin D has a potential role in immune regulation and it prevents infections especially urinary tract infections (UTI). Therefore it has positive regulatory role in both acute and recurrent infections especially in women of reproductive ages. As women at this age group have specific differences in their urinary tract and the reproductive organ anatomy, make them more prone for micro-organisms' invasion, The present study was carried out to ascertain certain relation between serum 25-hydroxyvitamin D levels and UTI in women while contemplating the significance of knowing the risk factors associated with UTI and also finding ways to avoid serious complications. 75 women with (case group) UTI were differentiated with 35 healthy with no UTI (control group) and 40 women with UTI and their serum 25-hydroxyvitamin D levels were checked in a case control study. The women were between at 17–52 years of age. Using ELISA, Serum 25-hydroxyvitamin D levels were measured. Analysis and comparison of the results were done among the two groups. Vitamin D mean levels in the case group was considerably lower when in comparison with the control group (11.09 ± 7.571 ng/mL vs. 24.08 ± 11.95 ng/mL, P < 0.001).     

Fibrinogen alpha chain O-glycopeptides as possible markers of urinary tract infection

Urinary tract infection (UTI) is the most common bacterial infection leading to substantial morbidity and considerable health care expenditures across all ages. Here we present an exploratory UPLC-MS study of human urine in the context of febrile, complicated urinary tract infection aimed to reveal and identify possible markers of a host response on infection. A UPLC-MS based workflow, taking advantage of Ultra High Resolution (UHR) Qq-ToF-MS, and multivariate data handling were applied to a carefully selected group of 39 subjects with culture-confirmed febrile Escherichia coli UTI. Using a combination of unsupervised and supervised multivariate modeling we have pinpointed a number of peptides specific for UTI. An unequivocal structural identification of these peptides, as O-glycosylated fragments of the human fibrinogen alpha 1 chain, required MS2 and MS3 experiments on two different MS platforms: ESI-UHR-Qq-ToF and ESI-ion trap, a blast search and, finally, confirmation was achieved by matching experimental tandem mass spectra with those of custom synthesized candidate-peptides.In conclusion, exploiting non-targeted UPLC-MS based approach for the investigation of UTI related changes in urine, we have identified and structurally characterized unique O-glycopeptides, which are, to our knowledge, the first demonstration of O-glycosylation of human fibrinogen alpha 1-chain.     

泌尿道感染动物模型制作研究现状

建立与人类泌尿道感染相似的可靠动物模型,对探讨泌尿道感染发病机制和研究治疗方法十分必要。本文介绍了急性肾盂肾炎,慢性肾盂肾炎,腺性膀胱炎等泌尿道感染模型制作研究现状,并从菌种,品系等角度进行探讨。     

Rates of mutation and host transmission for an Escherichia coli clone over 3 years

Although over 50 complete Escherichia coli/Shigella genome sequences are available, it is only for closely related strains, for example the O55:H7 and O157:H7 clones of E. coli, that we can assign differences to individual evolutionary events along specific lineages. Here we sequence the genomes of 14 isolates of a uropathogenic E. coli clone that persisted for 3 years within a household, including a dog, causing a urinary tract infection (UTI) in the dog after 2 years. The 20 mutations observed fit a single tree that allows us to estimate the mutation rate to be about 1.1 per genome per year, with minimal evidence for adaptive change, including in relation to the UTI episode. The host data also imply at least 6 host transfer events over the 3 years, with 2 lineages present over much of that period. To our knowledge, these are the first direct measurements for a clone in a well-defined host community that includes rates of mutation and host transmission. There is a concentration of non-synonymous mutations associated with 2 transfers to the dog, suggesting some selection pressure from the change of host. However, there are no changes to which we can attribute the UTI event in the dog, which suggests that this occurrence after 2 years of the clone being in the household may have been due to chance, or some unknown change in the host or environment. The ability of a UTI strain to persist for 2 years and also to transfer readily within a household has implications for epidemiology, diagnosis, and clinical intervention.     

New aspects of the role of MR/P fimbriae in Proteus mirabilis urinary tract infection

Proteus mirabilis, a common cause of urinary tract infection (UTI), produces a number of different fimbriae including mannose-resistant Proteus-like fimbriae (MR/P). The precise role of different P. mirabilis fimbriae in ascending UTI has not yet been elucidated. In this study, a clinical isolate of P. mirabilis and an isogenic mutant unable to express MR/P were tested using different experimental approaches. They were tested for their ability to cause infection in an ascending co-infection model of UTI and in a haematogenous model in the mouse. In both models, the mutant was less able than the wild-type strain to colonise the lower and upper urinary tracts although infectivity was not abolished. In vitro adherence to uroepithelial cells was also assessed. Significant differences in adherence between both strains were observed at 1 h but not at 15 min post infection. We have also shown that a wild-type strain carries two copies of the mrpA gene. These data reinforce the importance of MR/P fimbriae in P. mirabilis UTI although other virulence factors may be necessary for efficient colonisation and development of infection.