Immune activation and suppression by group B streptococcus in a murine model of urinary tract infection.

Diabetics have a higher incidence of urinary tract infection (UTI), are infected with a broader range of uropathogens, and more commonly develop serious UTI sequelae than nondiabetics. To better study UTI in the diabetic host, we created and characterized a murine model of diabetic UTI using the pancreatic islet beta-cell toxin streptozocin in C3H/HeN, C3H/HeJ, and C57BL/6 mouse backgrounds. Intraperitoneal injections of streptozocin were used to initiate diabetes in healthy mouse backgrounds, as defined by consecutive blood glucose levels of >250 mg/dl. UTIs caused by uropathogenic Escherichia coli (UTI89), Klebsiella pneumoniae (TOP52 1721), and Enterococcus faecalis (0852) were studied, and diabetic mice were found to be considerably more susceptible to infection. All three uropathogens produced significantly higher bladder and kidney titers than buffer-treated controls. Uropathogens did not have as large an advantage in the Toll-like receptor 4-defective C3H/HeJ diabetic mouse, arguing that the dramatic increase in colonization seen in C3H/HeN diabetic mice may partially be due to diabetic-induced defects in innate immunity. Competition experiments demonstrated that E. coli had a significant advantage over K. pneumoniae in the bladders of healthy mice and less of an advantage in diabetic bladders. In the kidneys, K. pneumoniae outcompeted E. coli in healthy mice but in diabetic mice E. coli outcompeted K. pneumoniae and caused severe pyelonephritis. Diabetic kidneys contained renal tubules laden with communities of E. coli UTI89 bacteria within an extracellular-matrix material. Diabetic mice also had glucosuria, which may enhance bacterial replication in the urinary tract. These data support that this murine diabetic UTI model is consistent with known characteristics of human diabetic UTI and can provide a powerful tool for dissecting this infection in the multifactorial setting of diabetes.

Objectives: To identify a better animal model that more closely mimics early renal interstitial fibrosis induced by long-term recurrent urinary tract infection (UTI), as occurs in humans, three different murine models were compared. Methods: Three different murine models of upper UTI were established, including direct injection of bacteria into renal tissues, ascending urinary infection with partial unilateral ureteric obstruction, and repeated infusion of bacteria into the bladder. The histopathology of the kidneys was assessed by hematoxylin and eosin staining. Masson's trichrome staining and immunohistochemistry for α-smooth muscle actin (α-SMA) expression were used for the detection of fibrosis. Results: All three models developed different levels of inflammation in the kidney. However, in contrast to the severe renal interstitial fibrosis in the other two models, the model of repeated infusion of bacteria into the bladder demonstrated early renal interstitial fibrosis by Masson's trichrome staining and immunohistochemistry for α-SMA. Conclusions: The model of repeated infusion of bacteria into the bladder developed low levels of renal interstitial fibrosis, which resembles the early tissue damage in the kidney induced by recurrent UTI s in humans. This model may therefore offer a better way to study the early therapeutic intervention of renal interstitial fibrosis caused by inflammation.

Urinary tract infections (UTIs) are among the most common infections caused by both Gram-negative and Gram-positive bacteria, acquired in the community and hospitals. There are three main groups of UTIs: (i) lower UTIs that affect the urethra or the bladder, (ii) upper UTIs that affect the kidneys, or (iii) asymptomatic bacteriuria (ABU). Group B Streptococcus (GBS) is a Gram-positive bacteria known to cause a variety of infections in neonates, pregnant women, the elderly or immunocompromised individuals. GBS has been estimated to cause 1-2% of all single organism UTIs. GBS has been shown to form biofilms, on abiotic and biotic surfaces, protecting it from killing by antibiotics or host immune cells and promotes host colonisation. Various factors have been shown to affect the biofilm forming ability of GBS. Here we determined that LB supplemented with glucose was the optimal media for biofilm formation by a strong biofilm forming strain. We then investigated the biofilm forming phenotype of 292 clinical GBS isolates that presented with asymptomatic, acute, or recurrent infection. We found that there was no significant difference in the biofilm forming ability across the clinical presentations. We also showed a significant reduction in the biofilm forming ability of a strong biofilm forming strain and its isogenic maeK and maeE mutants in LB supplemented with 1% glucose. A multiplex PCR screen for genes encoding bsaB, pil1, pil2a, and pil2b found that there was no significant difference in the number of strains that had the right sized fragments for all four genes across the three clinical presentations. We also found that there was a significant difference in the proportion of strains that had the right sized fragments for the pil genes across the three different levels of biofilm activity under shaking conditions. High biofilm forming strains had the lowest proportion of strains that possessed all four genes, compared to low and medium biofilm formers. Lastly, we assessed the haemolytic activity of the strains by growing them on tryptic soy agar plates supplemented with 5% horse blood and found that asymptomatic strains had a significantly higher number of strains with high haemolytic activity compared to acute and recurrent strains.

Contribution of yersiniabactin to the virulence of an Escherichia coli sequence type 69 (“clonal group A”) cystitis isolate in murine models of urinary tract infection and sepsis

Traditional folk treatments for the prevention and management of urinary tract infections (UTIs) and other infectious diseases often include plants and plant extracts that are rich in phenolic compounds. These have been ascribed a variety of activities, including inhibition of bacterial interactions with host cells. Here, we tested a panel of four well-studied phenolic compounds-caffeic acid phenethyl ester (CAPE), resveratrol, catechin, and epigallocatechin gallate-for the effects on host cell adherence and invasion by uropathogenic Escherichia coli (UPEC). These bacteria, which are the leading cause of UTIs, can bind and subsequently invade bladder epithelial cells via an actin-dependent process. Intracellular UPEC reservoirs within the bladder are often protected from antibiotics and host defenses and likely contribute to the development of chronic and recurrent infections. In cell culture-based assays, only resveratrol had a notable negative effect on UPEC adherence to bladder cells. However, both CAPE and resveratrol significantly inhibited UPEC entry into the host cells, coordinate with attenuated phosphorylation of the host actin regulator Focal Adhesion Kinase (FAK or PTK2) and marked increases in the numbers of focal adhesion structures. We further show that the intravesical delivery of resveratrol inhibits UPEC infiltration of the bladder mucosa in a murine UTI model and that resveratrol and CAPE can disrupt the ability of other invasive pathogens to enter host cells. Together, these results highlight the therapeutic potential of molecules like CAPE and resveratrol, which could be used to augment antibiotic treatments by restricting pathogen access to protective intracellular niches.IMPORTANCEUrinary tract infections (UTIs) are exceptionally common and increasingly difficult to treat due to the ongoing rise and spread of antibiotic-resistant pathogens. Furthermore, the primary cause of UTIs, uropathogenic Escherichia coli (UPEC), can avoid antibiotic exposure and many host defenses by invading the epithelial cells that line the bladder surface. Here, we identified two plant-derived phenolic compounds that disrupt activation of the host machinery needed for UPEC entry into bladder cells. One of these compounds, resveratrol, effectively inhibited UPEC invasion of the bladder mucosa in a mouse UTI model, and both phenolic compounds significantly reduced host cell entry by other invasive pathogens. These findings suggest that select phenolic compounds could be used to supplement existing antibacterial therapeutics by denying uropathogens shelter within host cells and tissues and help explain some of the benefits attributed to traditional plant-based medicines.

Maternal Colonization and Neonatal Group B Streptococcal Infection: Time to Universal Screening and Intrapartum Chemoprophylaxis in Taiwan?

Prevention of Group B streptococcus infection

Bacteriuria, or the presence of bacteria in urine, is associated with both asymptomatic, as well as symptomatic urinary tract infection (UTI) and underpins much of the dynamic of microbial colonization of the urinary tract. The prevalence of bacteriuria in dissimilar patient groups such as healthy adults, institutionalized elderly, pregnant women, and immune-compromised patients varies widely. In addition, assessing the importance of ‘significant bacteriuria’ in infected individuals represents a diagnostic challenge, partly due to various causal microbes, and requires careful consideration of the distinct etiologies of bacteriuria in different populations and circumstances. Recent molecular discoveries have revealed how some bacterial traits can enable organisms to grow in human urine, which, as a fitness adaptation, is likely to influence the progression of bacteriuria in some individuals. This study was designed as a comprehensive analysis of asymptomatic bacteriuria (ABU) causal organisms in dissimilar populations, and an in-depth microbiological analysis of the mechanisms used by one such causal organism, Streptococcus agalactiae. This organism causes UTI including ABU; however, growth of S. agalactiae in human urine has not been reported. In the first part of this study, we evaluate the prevalence and etiology of bacteruria, and discuss recent advances in the molecular detection of bacteriuria from a diagnostic viewpoint.

Group B Streptococcus (GBS) is a common cause of neonatal sepsis and meningitis. A major GBS virulence determinant is its sialic acid (Sia)-capped capsular polysaccharide. Recently, we discovered the presence and genetic basis of capsular Sia O-acetylation in GBS. We now characterize a GBS Sia O-acetylesterase that modulates the degree of GBS surface O-acetylation. The GBS Sia O-acetylesterase operates cooperatively with the GBS CMP-Sia synthetase, both part of a single polypeptide encoded by the neuA gene. NeuA de-O-acetylation of free 9-O-acetyl-N-acetylneuraminic acid (Neu5,9Ac(2)) was enhanced by CTP and Mg(2+), the substrate and co-factor, respectively, of the N-terminal GBS CMP-Sia synthetase domain. In contrast, the homologous bifunctional NeuA esterase from Escherichia coli K1 did not display cofactor dependence. Further analyses showed that in vitro, GBS NeuA can operate via two alternate enzymatic pathways: de-O-acetylation of Neu5,9Ac(2) followed by CMP activation of Neu5Ac or activation of Neu5,9Ac(2) followed by de-O-acetylation of CMP-Neu5,9Ac(2). Consistent with in vitro esterase assays, genetic deletion of GBS neuA led to accumulation of intracellular O-acetylated Sias, and overexpression of GBS NeuA reduced O-acetylation of Sias on the bacterial surface. Site-directed mutagenesis of conserved asparagine residue 301 abolished esterase activity but preserved CMP-Sia synthetase activity, as evidenced by hyper-O-acetylation of capsular polysaccharide Sias on GBS expressing only the N301A NeuA allele. These studies demonstrate a novel mechanism regulating the extent of capsular Sia O-acetylation in intact bacteria and provide a genetic strategy for manipulating GBS O-acetylation in order to explore the role of this modification in GBS pathogenesis and immunogenicity.

Development of a risk nomogram predicting urinary tract infection in patients with indwelling urinary catheter after radical surgery for cervical cancer.

The capsular polysaccharide (CPS) represents a key virulence factor for most encapsulated streptococci. Streptococcus suis and Group B Streptococcus (GBS) are both well-encapsulated pathogens of clinical importance in veterinary and/or human medicine and responsible for invasive systemic diseases. S. suis and GBS are the only Gram-positive bacteria which express a sialylated CPS at their surface. An important difference between these two sialylated CPSs is the linkage between the side-chain terminal galactose and sialic acid, being α-2,6 for S. suis but α-2,3 for GBS. It is still unclear how sialic acid may affect CPS production and, consequently, the pathogenesis of the disease caused by these two bacterial pathogens. Here, we investigated the role of sialic acid and the putative effect of sialic acid linkage modification in CPS synthesis using inter-species allelic exchange mutagenesis. To this aim, a new molecular biogenetic approach to express CPS with modified sialic acid linkage was developed. We showed that sialic acid (and its α-2,6 linkage) is crucial for S. suis CPS synthesis, whereas for GBS, CPS synthesis may occur in presence of an α-2,6 sialyltransferase or in absence of sialic acid moiety. To evaluate the effect of the CPS composition/structure on sialyltransferase activity, two distinct capsular serotypes within each bacterial species were compared (S. suis serotypes 2 and 14 and GBS serotypes III and V). It was demonstrated that the observed differences in sialyltransferase activity and specificity between S. suis and GBS were serotype unrestricted. This is the first time that a study investigates the interspecies exchange of capsular sialyltransferase genes in Gram-positive bacteria. The obtained mutants represent novel tools that could be used to further investigate the immunomodulatory properties of sialylated CPSs. Finally, in spite of common CPS structural characteristics and similarities in the cps loci, sialic acid exerts differential control of CPS expression by S. suis and GBS.

ObjectiveTo analyze the pathogen distribution of older type 2 diabetes mellitus (T2DM) patients with urinary tract infection (UTI) and to develop and validate the feasibility of a nomogram risk prediction model for older T2DM patients with UTI.MethodsWe retrospectively analyzed clinical data from older patients with T2DM admitted to the Department of Endocrinology of The First People’s Hospital of Lianyungang City from December 2023 to December 2024. Random number sequences were generated using R software, and all patients were assigned to the modeling cohort and validation cohorts in a ratio of 7:3 through simple random sampling. We compared baseline features between training and validation sets using appropriate statistical tests. We employed univariate and multivariate logistic regression models to identify factors independently associated with UTI in older patients with T2DM. Subsequently, we developed a nomogram prediction model, which was then validated using the validation group. Four methods of statistics, namely, the Hosmer–Lemeshow goodness-of-fit test (H-L test), subjects’ work characteristic curve and area under the curve (AUC), calibration curve, and clinical decision curve (DCA), were comprehensively applied to evaluate the model’s fit, discrimination, calibration, and clinical utility.ResultsAmong 521 older patients with T2DM, 82 developed UTI, with an incidence of 15.74%. Logistic regression analyses identified female (odds ratio [OR] = 2.53, 95% confidence interval [CI]: 1.25–5.12, P = 0.011), HbA1c (OR = 1.35, 95% CI: 1.15–1.59, P = 0.001), SGLT-2i in previous year (OR = 2.29, 95% CI: 1.19–4.41, P = 0.013), indwelling urinary catheter (OR = 3.04, 95% CI: 1.02–9.23, P = 0.048), and UTI in previous year (OR = 5.22, 95% CI: 2.22–12.25, P = 0.001) as independent risk factors for older T2DM patients with UTI. The AUC was 0.764 (95% CI: 0.683–0.898) in the training group and 0.779 (95% CI: 0.703–0.855) in the validation group. The H-L test results for the training (χ² = 9.834, P = 0.277) and validation (χ² = 5.432, P = 0.711) groups indicated good goodness-of-fit for the prediction model, with the internal validation curve demonstrating satisfactory performance.ConclusionEstablishing this simple, intuitive nomogram prediction model enables the early identification of risk factors in older T2DM patients with UTI. Based on readily accessible clinical variables, this model facilitates early risk stratification and promotes preventive interventions in a timely manner, ultimately reducing UTI incidence in clinical practice. Furthermore, the identified pathogen distribution and antimicrobial susceptibility profiles directly support targeted UTI treatment in this high-risk population, further enhancing the clinical utility of the predictive model and potentially improving patient outcomes.

Group B Streptococcus (GBS) colonisation affects around 13% of pregnant women and increases the risk of peripartum infection in newborns, preterm delivery and premature rupture of membranes. GBS infections are a major cause of neonatal sepsis. Early onset GBS (EOGBS) infections in the first seven days of life are particularly dangerous for newborns. Prevention is achieved by intrapartum antibiotic prophylaxis following a positive GBS screening during pregnancy. Screening strategies in pregnant women include universal GBS screening using a rectovaginal swab, assessment of maternal risk factors for EOGBS infection as a risk-based strategy, or a combination of both.The aim of this World Health Organization (WHO) recommendation was to improve the quality of care and outcomes for pregnant women and neonates with regard to the prevention of EOGBS. Consequently, there is a need to develop appropriate screening strategies for GBS in order to initiate intrapartum antibiotic prophylaxis.This recommendation was developed by a group of independent international experts and complements the existing recommendation on intrapartum antibiotic prophylaxis for positive GBS. It was developed in accordance with the WHO guideline development manual. This includes identification of key questions and outcomes, appraisal of the evidence, grading of the evidence using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach, and formulation of the recommendation by the guideline group, considering additional factors such as cost, pregnant women's and family values and preferences, as well as impact on health equity.WHO recommends that pregnant women be screened for the need for intrapartum antibiotic prophylaxis to reduce the risk of EOGBS infection. Either universal antenatal GBS screening or a risk-based strategy should be offered as a screening strategy. Pregnant women with a positive test result or at increased risk should receive intrapartum antibiotic prophylaxis.

Urinary tract infection (UTI) is one of the most common bacterial infections worldwide. Experimental models that accurately reflect the high susceptibility to UTI in humans have, however, been lacking. This situation has limited detailed research into the early bladder colonization by uropathogens and the early innate defence mechanisms elicited to prevent this. We recently presented a model of urinary tract infection in pigs, animals that are naturally susceptible to UTI and have greater similarity to the physiology and anatomy of the human urinary tract than traditional rodent UTI models. In the current study, we used the pig model to investigate the minimal infectious inoculum of uropathogenic Escherichia coli, the most common cause of urinary tract infection. We show that in this animal a few individual bacteria that come into contact with the urothelium can give rise to fulminant cystitis, indicating the high infectious potential of uropathogenic E. coli.

Urinary tract infections and reproductive tract infections pose significant health risks, particularly among women living in challenging conditions. Unhygienic menstrual practices can exacerbate these risks, impacting physical and psychological well-being. This study assessed the association between unhygienic menstrual care and self-reported urinary tract infection/reproductive tract infection symptoms among refugee women. In addition, it explored the association between these symptoms and mental health, specifically depressive symptoms. This study adopted a cross-sectional observational design. This study was conducted between January and March 2023, involving 387 reproductive-age refugee women. Data collected included sociodemographic information and urinary tract infection/reproductive tract infection symptoms. In addition, we used the Menstrual Practice Needs Scale to evaluate menstrual hygiene practices and the Patient Health Questionnaire-9 for depressive symptoms. Statistical analysis was performed using Python version 3.9.12. Of 387 refugee women, 92.25% reported having urinary or reproductive tract infection symptoms in the previous 3 months. Factors like older age (odds ratio = 1.764, 95% confidence interval = 1.083-2.873, p-value = 0.023), lower family income (odds ratio = 0.327, 95% confidence interval = 0.138-0.775, p-value = 0.011), lower educational level (odds ratio = 0.222, 95% confidence interval = 0.068-0.718, p-value = 0.012), and being married (odds ratio = 0.328, 95% confidence interval = 0.188-0.574, p-value < 0.001) were significantly associated with urinary or reproductive tract infection risk. Difficulties obtaining menstrual products and thus reusing them increased the odds of urinary or reproductive tract infection diagnosis (odds ratio = 2.452, 95% confidence interval = 1.497-4.015, p-value < 0.001). Women with urinary or reproductive tract infection symptoms exhibited higher Patient Health Questionnaire-9 scores than those without (12.14 ± 5.87 vs 9.99 ± 5.86, p-value < 0.001, respectively). This study highlights a high prevalence of urinary or reproductive tract infection symptoms among refugee women residing in camps in Jordan, which was associated with poor menstrual hygiene practices and depressive symptoms. To reduce the urinary tract infection/reproductive tract infection burden in marginalized communities, public health initiatives should enhance healthcare accessibility, provide reproductive education, and promote holistic well-being practices for refugee women.