Ureteral stent-associated infection and sepsis: pathogenesis and prevention: a review

Trimethylamine N-Oxide-Derived Zwitterion Coating for Polyurethane Ureteral Stents Prevents Encrustation Formation

A ureteral stent with strong resistance to proteins, bacteria, and multivalent ions is crucial for the safe treatment of urologic diseases. Generally, the proteins, bacteria, and multivalent ions present in urine tend to bind to the stent surface, leading to aggregation, nucleation, and subsequent stent encrustation. Stent encrustation can induce or exacerbate urinary tract infections and obstructions, thereby seriously harming kidney function. Although hydrophilic coatings on ureteral stents can reduce the binding of proteins, bacteria, and multivalent ions, encrustation still occurs. To date, preventing stent encrustation formation remains a significant challenge. Here, we grafted dense trimethylamine oxide (TMAO)-derived zwitterionic polymers onto the stent surface via a branched amplification strategy. These zwitterions can strongly bind water molecules, forming a stable hydration shell that repels proteins, bacteria, and multivalent ions from adhering to the surface of the polyurethane ureteral stent, thus rendering the stent anti-encrustation. The results showed that the TMAO-derived zwitterion-coated stents exhibited a significantly reduced encrustation weight (13.8% of the original polyurethane stent) and demonstrated good safety. This approach offers a promising method for enhancing stent encrustation resistance. STATEMENT OF SIGNIFICANCE: This study successfully developed a TMAO-derived zwitterionic coating on the surface of a polyurethane stent, creating a superhydrophilic surface with a minimal contact angle of 5.2o. This surface effectively shields the stent from interactions with proteins, bacteria, and multivalent ions in urine, demonstrating favorable anti-protein adsorption and antibacterial adhesion properties. The superhydrophilic surface formed by the TMAO-derived zwitterionic coating on the stents (PTMAO-s) provides strong anti-fouling resistance and enhanced anti-encrustation properties. Under identical conditions, the encrustation resistance of PTMAO-s is approximately 7.2-fold greater than that of original polyurethane stents (PU), 3.6-fold greater than Bard commercial stents, and 2.1-fold greater than betaine-coated stents (PSBG-s).

Clinicopathologic and Etiologic Characteristics of Urinary Tract Infections in Patients with Cervical Cancer Undergoing Radical Operation with Indwelling Ureteral Stents

Background: The objective of this study was to investigate the clinicopathologic and etiologic characteristics of urinary tract infections in patients with cervical cancer who had undergone radical operation with ureteral stent insertion. Patients and Methods: We conducted a retrospective analysis on the medical records of 24 patients who underwent radical operation for cervical cancer with indwelling ureteral stents at Shanghai General Hospital between April 2019 and December 2022. Results: A total of 15 patients experienced urinary tract infections, resulting in an infection rate of 62.5%. Although postoperative adjuvant chemotherapy might have been a potential risk factor for urinary tract infections, the difference was not statistically significant (p = 0.074). A total of 30 pathogen strains were isolated, with Escherichia coli being the most prevalent. Notably, two strains of carbapenem-resistant Enterobacteriaceae were identified. The majority of patients (70.83%) had ureteral stents in place for 3-12 months. As the duration of stent insertion exceeded 2 months, we noted a decrease in antibiotic sensitivity against the same pathogen. Furthermore, fungal infections became more prevalent when the stent placement duration surpassed 4 months. Conclusions: The incidence of urinary tract infection is exceptionally high in patients with locally advanced cervical cancer and who have undergone radical operation with ureteral stent insertion. E. coli strains exhibited relative resistance to penicillins and cephalosporins. With prolonged stent placement, there was a notable diminution in antibiotic sensitivity against the same pathogen, and the microbial profile shifted from bacteria to fungi. This study provides valuable insights for the determination of the optimal timing for stent removal or replacement and for the selection of effective antibiotics to treat urinary tract infections for patients with indwelling ureteral stents, so as to ultimately prevent severe infections and mitigate disease burden.

Comprehensive analysis of the bacterial spectrum for enhanced clinical insight in microbial ureteral stent colonization, uncomplicated urinary tract infections and catheter-associated urinary tract infections: a principal component analysis-based literature review

PURPOSE

Controversies exist regarding the prevailing spectrum of microorganisms in microbial ureteral stent colonization (MUSC) and their clinical significance. The aim of this comprehensive review is to determine the predominant microbial spectrum in patients with an indwelling ureteral stent in comparison to catheter-associated urinary tract infections (CAUTI) and uncomplicated urinary tract infections (UTI).

METHODS

Google scholar, PubMed, Embase, Medline, and Cochrane literature databases were searched from inception to April 2022 to identify manuscripts on MUSC, uncomplicated UTI and CAUTI. A principal component analysis (PCA) was performed to identify patterns of the pathogen spectrum of the different groups.

RESULTS

We included 29 studies on MUSC, 28 studies on uncomplicated UTI and 23 CAUTI studies. The proportion of Staphylococci, Enterococci and Candida were significantly higher in MUSC and stent associated bacteriuria compared to their proportion in uncomplicated UTIs where E. coli dominates. By comparing MUSC, CAUTI and UTI with a PCA, the detected pathogen spectrum exhibited clearly distinguishable trends in the frequency of the main isolated pathogens influencing these three groups of urinary tract infections. With respect to MUSC and UTI, their 95% confidence interval ellipse only showed minimal overlap emphasizing that the spectrum of pathogens in the two groups is clearly distinct.

CONCLUSIONS

The frequency of detection of Staphylococci, Enterococci and Candida is more common in MUSC as compared to UTI. Thus, patients with indwelling ureteral stents should undergo an antimicrobial prophylaxis targeting this microbial spectrum in case of further surgery.

Bacterial Communities and Their Role in Bacterial Infections

Since infections associated with microbial communities threaten human health, research is increasingly focusing on the development of biofilms and strategies to combat them. Bacterial communities may include bacteria of one or several species. Therefore, examining all the microbes and identifying individual community bacteria responsible for the infectious process is important. Rapid and accurate detection of bacterial pathogens is paramount in healthcare, food safety, and environmental monitoring. Here, we analyze biofilm composition and describe the main groups of pathogens whose presence in a microbial community leads to infection (Staphylococcus aureus, Enterococcus spp., Cutibacterium spp., bacteria of the HACEK, etc.). Particular attention is paid to bacterial communities that can lead to the development of device-associated infections, damage, and disruption of the normal functioning of medical devices, such as cardiovascular implants, biliary stents, neurological, orthopedic, urological and penile implants, etc. Special consideration is given to tissue-located bacterial biofilms in the oral cavity, lungs and lower respiratory tract, upper respiratory tract, middle ear, cardiovascular system, skeletal system, wound surface, and urogenital system. We also describe methods used to analyze the bacterial composition in biofilms, such as microbiologically testing, staining, microcolony formation, cellular and extracellular biofilm components, and other methods. Finally, we present ways to reduce the incidence of biofilm-caused infections.

Biofunctional coatings and drug-coated stents for restenosis therapy

Palliative therapy utilizing interventional stents, such as vascular stents, biliary stents, esophageal stents, and other stents, has been a prevalent clinical strategy for treating duct narrowing and partial blockage. However, stent restenosis after implantation usually significantly compromises therapeutic efficacy and patient safety. Clinically, vascular stent restenosis is primarily attributed to endothelial hyperplasia and coagulation, while the risk of biliary stent occlusion is heightened by bacterial adhesion and bile sludge accumulation. Similarly, granulation tissue hyperplasia leads to tracheal stent restenosis. To address these issues, surface modifications of stents are extensively adopted as effective strategies to reduce the probability of restenosis and extend their functional lifespan. Applying coatings is one of the technical routes involving a complex selection of materials, drug loading capacities, release rates, and other factors. This paper provides an extensive overview of state of the art drug-coated stents, addressing both challenges and future prospects in this domain. We aim to contribute positively to the ongoing development and potential clinical applications of drug-coated stents in interventional therapy.

Exploring Condition-Specific Variability in the Ureteral Stent Microbiome

(1) Background: Indwelling ureteral stents are commonly used urological devices to maintain ureteral patency, yet they have been associated with complications such as infections. Some studies have shown that bacteria adhere to and create an antimicrobial-resistant biofilm on stents. One factor that may impact biofilm formation is the original condition informing stent placement, such as kidney stones and renal allografts. Both kidney stones and renal allografts are independently associated with infection, yet the differential stent microbiomes of these populations remain poorly characterized. Our objective was to characterize these microbiomes in order to inform urological health practice and help prevent ureteral stent-associated infections. (2) Methods: Stents were collected from kidney stone and renal transplant recipients undergoing routine cystoscopic stent removal. Microbial DNA was extracted from stents and analyzed using 16S Next Generation Sequencing. Descriptive statistics, alpha diversity, and beta diversity methods were used for statistical analysis. (3) Results: The microbiome of ureteral stents in kidney stone and transplant patients is composed of unique species, each with different biofilm-forming abilities. (4) Conclusions: Our findings demonstrate that the microbiome of stents differs based on preceding condition. It is important to conduct future studies that explore this microbiome further to understand what type of stent-associated infection someone may develop based on their initial condition.

Step by step technique of Stentless Florence Robotic Intracorporeal Neobladder (FloRIN), does the ureteral management influence functional outcomes?

INTRODUCTION

Benefits and harms of avoid the sent placement during IntraCorporeal Neobladder configuration are still debated. Our objective was to describe the step-by-step technique of Florence intracorporeal neobladder (FloRIN) configuration performed with stentless procedure focusing on perioperative and mid-term functional outcomes.

MATERIALS AND METHODS

In this single institution prospective randomized 1:1 series all consecutive patients underwent Robot-Assisted Radical Cystectomy (RARC) and FloRIN reconfiguration from January 2021 to March 2021 were enrolled. Functional perioperative and mid-term outcomes were gathered. Postoperative complications were graded according to Clavien-Dindo classification and divided in early (<30 days from discharge) and delayed (>30 days).

RESULTS

Overall, 10 patients were included in the analysis. Of these, the 50.0% was treated with Stentless FloRIN. In terms of baseline features, no differences were recorded between the two groups. Median age was 65 and 66 years while median BMI was 27 and 25 in the stentless and in the stent group, respectively. Concerning intraoperative variables, no intraoperative complications as well as open conversion occurred among both groups. As regard introperative features, a shorter console time was associated with stentless procedure (331 min vs 365 min). In terms of perioperative outcomes, canalization and time to drainage removal didn't differ between groups while length of hospital stay was significantly lower in stentless group 10 days versus 14 days. Early and delayed postoperative complication rate was not influenced by the ureteral management at a preliminary assessment with comparable rates of Clavien Dindo ⩾ 3a between the two groups. Mid-term functional outcomes did not differ between groups in terms of kidney function loss.

CONCLUSIONS

FloRIN with Stentless technique showed functional and perioperative preliminary outcomes comparable with the standard ureteral management strategy. Further series with longer functional follow-up assessment will be needed to confirm our preliminary results.

Practical Guidance for Clinical Microbiology Laboratories: Microbiologic diagnosis of implant-associated infections

SUMMARYImplant-associated infections (IAIs) pose serious threats to patients and can be associated with significant morbidity and mortality. These infections may be difficult to diagnose due, in part, to biofilm formation on device surfaces, and because even when microbes are found, their clinical significance may be unclear. Despite recent advances in laboratory testing, IAIs remain a diagnostic challenge. From a therapeutic standpoint, many IAIs currently require device removal and prolonged courses of antimicrobial therapy to effect a cure. Therefore, making an accurate diagnosis, defining both the presence of infection and the involved microorganisms, is paramount. The sensitivity of standard microbial culture for IAI diagnosis varies depending on the type of IAI, the specimen analyzed, and the culture technique(s) used. Although IAI-specific culture-based diagnostics have been described, the challenge of culture-negative IAIs remains. Given this, molecular assays, including both nucleic acid amplification tests and next-generation sequencing-based assays, have been used. In this review, an overview of these challenging infections is presented, as well as an approach to their diagnosis from a microbiologic perspective.

Sepsis risk in diabetic patients with urinary tract infection

BACKGROUND

Urinary tract infections (UTI) is a prevalent condition in those with diabetes, and in severe cases, it may escalate to sepsis. Therefore, it is important to analyze the risk variables associated with sepsis in diabetes individuals with UTI.

METHODS

This research was a retrospective cross-sectional analysis. From January 2011 to June 2022, a group of individuals with diabetes were identified as having UTI at a tertiary hospital situated in Southeastern China. Patient data, including information on urine culture, was collected retrospectively from a clinical record database. The participants were categorized into the sepsis and non-sepsis groups. The risk variables were derived using both uni-and multiple- variable regression analysis.

RESULTS

The research included 1919 patients, of whom 1106 cases (57.63%) had positive urine cultures. In total, 445 blood culture samples were tested, identifying 186 positive cases (41.80%). The prevalence of bacteria in urine and blood samples was highest for Escherichia coli and Klebsiella pneumoniae, respectively. Moreover, 268 individuals (13.97%) exhibited sepsis. The regression analysis indicated a positive correlation between sepsis and albumin (ALB)<34.35 g/L, C-reactive protein (CRP)>55.84 mg/L and white blood cell count (WBC) >8.485 X 109/L in diabetic cases with UTIs. By integrating the three aforementioned parameters, the area under the receiver operating characteristic curve was 0.809.

CONCLUSIONS

The early detection of sepsis in diabetic individuals with UTI may be achieved using a comprehensive analysis of CRP, WBC, and ALB test findings.

Factors influencing bacterial colonization of double J ureteral stents: a prospective study

Background

To investigate the microorganisms responsible for double J stent (DJS) colonization, bacteriuria, and the drug susceptibility of the isolates. We also tried to determine factors associated with stent colonization, such as indwelling time, sex, age, and comorbidities.

Materials and methods

This study is a prospective analysis of patients following DJS ablation. A total of 155 patients from our institution were enrolled in this study between January 2023 and May 2023. Bladder urine was collected in a sterile container prior to stent removal for bacteriological exam. The removed stents were divided into three parts: top (Renal), middle (Ureteral), and bottom (Bladder); 3 cm pieces from each part were taken and placed in a sterile test tube for bacteriological investigation.

Results

The mean age of patients with positive stent culture was 61.17±12.82 versus 55.94±10.32 when stent culture is negative, which is statistically significant P=0.016. Diabetes and bacteriuria are both correlated with DJS contamination with P<0.001 in the two cases. The mean duration of the use of DJS in patients with colonized stent culture is 6.45±2.98 months versus 4.06±2.20 months for the other patients; the difference is statistically significant P<0.001. The most commonly isolated pathogens on stents were Gram-negative bacilli (53.2%), dominated by Enterobacteriaceae in 19 cases (55.2%).

Conclusion

Indwelling time is the only unanimous factor of stent colonization in literature, so we recommend using DJS only if necessary and to remove it as soon as possible.

Stentless florence robotic intracorporeal neobladder (FloRIN), a feasibility prospective randomized clinical trial

INTRODUCTION

Aim of the study was to evaluate perioperative, postoperative and mid-term functional outcomes of Florence intracorporeal neobladder (FloRIN) configuration technique performed with stentless procedure.

MATERIALS AND METHODS

This single institution randomized 1:1 prospective series included consecutive patients treated with Robot-Assisted Radical Cystectomy (RARC) and FloRIN reconfiguration from January 2021 to February 2022. Postoperative complications were graded according to Clavien Dindo classification and divided in early (<30 days from discharge) and delayed (>30 days).

RESULTS

Overall, 63 patients were included in the analysis. Among these 32 (50.8 %) were treated with RARC + stentless FloRIN while 31 (49.2 %) underwent stent placement procedure. No differences were found in terms of baseline characteristics between the two groups. Stentless procedure was associated with significant shorter console time 328 vs 374 min (p = 0.04) and lower estimated blood loss (EBL) 330 vs 350 ml (p = 0.04) comparing to stent group. As regards perioperative features, no significant differences were recorded in terms of canalization (p = 0.58) and time to drainage removal (p = 0.11) while a shorter length of hospital stay was found in case of stentless procedure (p = 0.04). Early postoperative complications Clavien ≥ 3a occurred in 9.3 % and 12.9 % of patients while delayed major complications were recorded in the 3.1 % and 9.6 % of patients treated with stentless and stent FloRIN, respectively (p = 0.09). As regards the mid-term functional outcomes, no differences were found in terms of kidney function loss in both 3rd and 6th month assessment (p = 0.13 and p = 0.14, respectively).

CONCLUSIONS

In conclusion, Stentless FloRIN is a feasible and safe IntraCorporeal Neobladder technique, as confirmed by the worthy functional and perioperative outcomes achieved in comparison with the standard FloRIN ureteral management strategy.

Four-year variation in pathogen distribution and antimicrobial susceptibility of urosepsis: a single-center retrospective analysis

Background

Urosepsis is a common disease in urology, which is characterized by high treatment costs and high mortality. In the treatment of sepsis, anti-infection therapy is the most important means. However, the effect of empirical anti-infection therapy is often not ideal. Therefore, it is necessary to continuously monitor the prevalence of bacterial isolates in the blood culture of patients with urinary sepsis and their sensitivity to antibacterial drugs. This is of great significance to improve the efficacy of empirical antibiotic therapy for urosepsis.

Objective

To elucidate the landscape of prevailing bacterial profiles and their antimicrobial susceptibilities in urosepsis cases, and to furnish robust clinical evidence to underpin the timely initiation of empirical antibiotic treatment.

Methods

Collect the basic information and blood culture results of patients with urosepsis hospitalized from 2017 to 2020. Retrospective analysis of bacterial species and antimicrobial susceptibility in urosepsis and changes over 4 years.

Results

Gram-negative bacteria (178 isolates, 75.11%) constituted the main pathogens causing urosepsis, followed by Gram-positive bacteria (46 isolates, 19.41%) and fungus (13 isolates, 5.48%). The sensitivity of ertapenem, meropenem, amikacin, and imipenem to Gram-negative bacteria all exceeded 85%. The sensitivity rates of levofloxacin, gentamicin, and ciprofloxacin are decreasing every year (p < 0.05). Tigecycline, vancomycin, and linezolid exhibited excellent sensitivity against Gram-positive bacteria. Among fungi, fluconazole demonstrated universal sensitivity, while itraconazole-resistant isolates have been found, and amphotericin B is still effective.

Conclusion

Analysis of blood culture results of patients more accurately reflected the etiology of urosepsis, mainly Escherichia coli, Enterococcus, and Klebsiella pneumoniae. If there are no definitive blood culture results, empiric treatment of urosepsis should not include fluoroquinolone antibiotics. Cefepime, cefoxitin, and ceftazidime are the most sensitive antibiotics to Gram-negative bacteria besides carbapenem antibiotics. In addition, the current situation regarding extended-spectrum β-lactamase-producing bacteria and carbapenem-resistant Enterobacteriaceae bacteria resistance is extremely concerning with limited therapeutic options available. Strengthening antibiotic management practices and exploring novel antibacterial agents can help mitigate this issue.

Analysis of Pathogens of Urinary Tract Infections Associated with Indwelling Double-J Stents and Their Susceptibility to Globularia alypum

Ureteral double-J stents are frequently used to prevent urinary obstruction. They can develop bacterial colonization and encrustation, which leads to persistent infections that seldom respond to antibiotic treatment. Thus, the goal of this study was to evaluate the local spectrum of bacterial pathogens and their susceptibility to natural compounds. A total of 59 double-J ureteral stents from 59 consecutive patients were examined. The samples were inoculated on agar culture mediums. Extracts of Globularia alypum L. were evaluated for their antibacterial activity with the diffusion and broth dilution methods; for antibiofilm activity, the crystal violet assay was used. The identification and the quantification of the different constituents of extracts were determined by reverse-phase high-performance liquid chromatography (RP-HPLC). Bacterial growth was found in three patients (5.1%). Enterococcus faecalis (1.7%), Acinetobacter baumanii (1.7%), and Pseudomonas putida (1.7%) strains were more commonly detected. They were resistant to several common antibiotics. All extracts presented several components, mainly nepetin-7-glucoside and trans-ferulic-acid, and they had antibacterial activity (MIC = 6.25 mg/mL and MBC = 6.25 mg/mL), and antibiofilm (59.70% at 25 mg/mL) properties, especially against Acinetobacter baumanii. The results achieved confirm the important role of this plant as a source of therapeutic activities.

Analysis of Bacterial Stent Colonization: The Role of Urine and Device Microbiological Cultures

In this study, we explored the incidence of double J (JJ) contamination of patients who underwent an endourological procedure for urinary stones and ureteral stenosis. We developed a prospective study between January 2019 and December 2021. Ninety-seven patients, 54 male and 43 female, were enrolled. Urine culture was taken during four steps: before stent insertion, a sample from selective renal pelvis catheterization, a sample two days after the JJ insertion and finally, after the stent removal procedure. At the time of the stent removal, 1 cm of proximal and distal ends were cut off and placed in the culture for bacterial evaluation. Cohen's kappa coefficient value (k) and concordance rates of microbiological culture results were evaluated. The study group comprised 56% of male patients. Proximal and distal stent cultures were positive in 81 and 78 patients. The concordance rate of microbiological cultures between proximal and distal double J stent is 88% (k 0.6). The most common pathogens isolated from urine and stent cultures were Enterococcus spp. in 52 cases and Klebsiella spp. in 27 cases.

The relationship between admission hyperglycaemia and urinary tract infections in geriatric patients with hip fractures

PURPOSE

This study investigated the association of admission hyperglycaemia with catheter-associated urinary tract infections (CAUTIs) and catheter-unassociated urinary tract infections (CUUTIs) in elderly patients with hip fractures.

METHODS

In an observational cohort study of elderly patients with hip fractures, glucose values were collected within 24 h of admission. Urinary tract infections were classified as CAUTIs and CUUTIs. Multivariate logistic regression analysis and propensity score matching obtained adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for urinary tract infections. Subgroup analyses were further explored to investigate the relationship between admission hyperglycemia and urinary tract infections.

RESULTS

The study included 1279 elderly patients with hip fractures, 298 (23.3%) of whom had urinary tract infections upon hospitalization (including 182 CAUTIs and 116 CUUTIs). Propensity score matching indicated that patients with glucose levels exceeding 10.00 mmol/L had significantly higher odds of developing CAUTIs (OR 3.10, 95% CI 1.65-5.82) than those with glucose levels between 4.00-6.09 mmol/L. It is worth noting that patients with blood glucose levels greater than 10.00 mmol/L have a higher susceptibility for CUUTIs (OR 4.42, 95% CI 2.09-9.33) than CAUTIs. The subgroup analyses observed significant interactions between diabetes and CAUTIs (p for interaction = 0.01) and between bedridden time and CUUTIs (p for interaction = 0.04).

CONCLUSIONS

Elderly hip fracture patients with admission hyperglycaemia have an independent association with CAUTIs and CUUTIs. The association is stronger with CUUTIs and necessitates clinician intervention if blood glucose levels at admission exceed 10 mmol/L.

Ureteric stent associated spondylodiscitis

This case report describes a clinical presentation of spondylodiscitis, following an emergency ureteric stent placement for an infected and obstructed kidney in a woman in her late 70s who presented with right flank pain, raised inflammatory markers and an acute kidney injury. Non-contrast CT kidney, ureters and bladder (KUB) revealed a 9 mm obstructing stone and prompt decompression with a JJ stent was performed. Although the urine culture showed no growth at first, an extended spectrum beta-lactamase Escherichia coli was found in a subsequent urine culture after discharge. Postoperatively, the patient described a novel, worsening lower back pain and had persistently elevated inflammatory markers. An MRI revealed spondylodiscitis of L5/S1, for which she was treated with a 6-week course of antibiotics, and she has made a good but slow recovery. This case shows the unusual finding of spondylodiscitis postureteric stent placement and clinicians should be aware of this rare complication.

Impact of Preoperative Ureteral Stenting in Retrograde Intrarenal Surgery for Urolithiasis

Background and Objectives: Ureteral stent insertion passively dilates the ureter. Therefore, it is sometimes used preoperatively before flexible ureterorenoscopy to make the ureter more accessible and facilitate urolithiasis passage, especially when ureteroscopic access has failed or when the ureter is expected to be tight. However, it may cause stent-related discomfort and complications. This study aimed to assess the effect of ureteral stenting prior to retrograde intrarenal surgery (RIRS). Materials and Methods: Data from patients who underwent unilateral RIRS for renal stone with the use of a ureteral access sheath from January 2016 to May 2019 were retrospectively analyzed. Patient characteristics, including age, sex, BMI, presence of hydronephrosis, and treated side, were recorded. Stone characteristics in terms of maximal stone length, modified Seoul National University Renal Stone Complexity score, and stone composition were evaluated. Surgical outcomes, including operative time, complication rate, and stone-free rate, were compared between two groups divided by whether preoperative stenting was performed. Results: Of the 260 patients enrolled in this study, 106 patients had no preoperative stenting (stentless group), and 154 patients had stenting (stenting group). Patient characteristics except for the presence of hydronephrosis and stone composition were not statistically different between the two groups. In surgical outcomes, the stone-free rate was not statistically different between the two groups (p = 0.901); however, the operation time for the stenting group was longer than that of the stentless group (44.8 ± 24.2 vs. 36.1 ± 17.6 min; p = 0.001). There were no differences in the complication rate between the two groups (p = 0.523). Conclusions: Among surgical outcomes for RIRS with a ureteral access sheath, preoperative ureteral stenting does not provide a significant advantage over non-stenting with respect to the stone-free rate and complication rate.

Fluid mechanical performance of ureteral stents: The role of side hole and lumen size

Ureteral stents are indispensable devices in urological practice to maintain and reinstate the drainage of urine in the upper urinary tract. Most ureteral stents feature openings in the stent wall, referred to as side holes (SHs), which are designed to facilitate urine flux in and out of the stent lumen. However, systematic discussions on the role of SH and stent lumen size in regulating flux and shear stress levels are still lacking. In this study, we leveraged both experimental and numerical methods, using microscopic-Particle Image Velocimetry and Computational Fluid Dynamic models, respectively, to explore the influence of varying SH and lumen diameters. Our results showed that by reducing the SH diameter from 1.1 to 0.4 mm the median wall shear stress levels of the SHs near the ureteropelvic junction and ureterovesical junction increased by over 150 % , even though the flux magnitudes through these SH decreased by about 40 % . All other SHs were associated with low flux and low shear stress levels. Reducing the stent lumen diameter significantly impeded the luminal flow and the flux through SHs. By means of zero-dimensional models and scaling relations, we summarized previous findings on the subject and argued that the design of stent inlet/outlet is key in regulating the flow characteristics described above. Finally, we offered some clinically relevant input in terms of choosing the right stent for the right patient.

Prevention of device-related infections in patients with cancer: Current practice and future horizons

Over the past several years, multifaceted advances in the management of cancer have led to a significant improvement in survival rates. Throughout patients' oncological journeys, they will likely receive one or more implantable devices for the administration of fluids and medications as well as management of various comorbidities and complications related to cancer therapy. Infections associated with these devices are frequent and complex, often necessitating device removal, increasing health care costs, negatively affecting quality of life, and complicating oncological care, usually leading to delays in further life-saving cancer therapy. Herein, the authors comprehensively review multiple evidence-based recommendations along with best practices, expert opinions, and novel approaches for the prevention of diverse device-related infections. The authors present many general principles for the prevention of these infections followed by specific device-related recommendations in a systematic manner. The continuous involvement and meaningful cooperation between regulatory entities, industry, specialty medical societies, hospitals, and infection control-targeted interventions, along with primary care and consulting health care providers, are all vital for the sustained reduction in the incidence of these preventable infections.

Analysis of Characteristics, Pathogens and Drug Resistance of Urinary Tract Infection Associated with Long-Term Indwelling Double-J Stent

Objective

To investigate the characteristics, pathogens and drug resistance of urinary tract infection (UTI) associated with long-term indwelling double-J stent.

Methods

The clinical data of 102 patients with urinary tract infection associated with long-term indwelling double-J stent in University-Town Hospital of Chongqing Medical University and Chongqing Traditional Chinese Medicine Hospital from September 2010 to July 2022 were collected retrospectively, and the difference between etiological characteristics were analyzed. Urine and double-J stent samples of patients were collected for pathogen identification and drug sensitivity test.

Results

A total of 102 patients, 39 (38.23%) males and 63 (61.77%) females, aged 24-72 years, with a median age of 48 years, were included in this study. Urinary calculi (40.20%) and ureteral stricture (24.50%) were the main causes of urinary tract infection associated with long-term indwelling double-J stent. Among the patients with urinary tract infection caused by double-J stent, female patients were higher than male patients (61.77% vs 38.23%). In terms of positive rate of pathogenic bacteria culture, the rate of double-J stent was higher than that of urine (67.65% vs 35.29%). The main pathogenic bacteria in urine were Escherichia coli (30.55%) of Gram negative bacteria, while the main pathogenic bacteria in double-J stent were enterococcus faecalis (27.53%) of Gram positive bacteria. The resistance rate of Gram positive bacteria in double-J stent to vancomycin, ciprofloxacin, meropenem and piperacillin/tazobactam was significantly higher than that in urine (P<0.05). The resistance rate of Gram negative bacteria in double-J stent to imipenem, cefepime, piperacillin/tazobactam, meropenem and cefoperazone/sulbactam was significantly higher than that in urine (P<0.05).

Conclusion

Double-J stent associated urinary tract infection is more common in women than in men. Escherichia coli and Enterococcus faecalis are the main pathogens, and the pathogens show strong drug resistance.

Staphylococcus aureus ST1 promotes persistent urinary tract infection by highly expressing the urease

Staphylococcus aureus (SA) is a relatively uncommon cause of urinary tract infections (UTIs) in the general population. Although rare, S. aureus-induced UTIs are prone to potentially life-threatening invasive infections such as bacteremia. To investigate the molecular epidemiology, phenotypic characteristics, and pathophysiology of S. aureus-induced UTIs, we analyzed non-repetitive 4,405 S. aureus isolates collected from various clinical sources from 2008 to 2020 from a general hospital in Shanghai, China. Among these, 193 isolates (4.38%) were cultivated from the midstream urine specimens. Epidemiological analysis showed UTI-derived ST1 (UTI-ST1) and UTI-ST5 are the primary sequence types of UTI-SA. Furthermore, we randomly selected 10 isolates from each of the UTI-ST1, non-UTI-ST1 (nUTI-ST1), and UTI-ST5 groups to characterize their in vitro and in vivo phenotypes. The in vitro phenotypic assays revealed that UTI-ST1 exhibits an obvious decline in hemolysis of human red blood cells and increased biofilm and adhesion in the urea-supplemented medium, compared to the medium without urea, while UTI-ST5 and nUTI-ST1 did not show significant differences between the biofilm-forming and adhesion abilities. In addition, the UTI-ST1 displayed intense urease activities by highly expressing urease genes, indicating the potential role of urease in UTI-ST1 survival and persistence. Furthermore, in vitro virulence assays using the UTI-ST1 ureC mutant showed no significant difference in the hemolytic and biofilm-forming phenotypes in the presence or absence of urea in the tryptic soy broth (TSB) medium. The in vivo UTI model also showed that the CFU of the UTI-ST1 ureC mutant rapidly reduced during UTI pathogenesis 72 h post-infection, while UTI-ST1 and UTI-ST5 persisted in the urine of the infected mice. Furthermore, the phenotypes and the urease expression of UTI-ST1 were found to be potentially regulated by the Agr system with the change in environmental pH. In summary, our results provide important insights into the role of urease in S. aureus-induced UTI pathogenesis in promoting bacterial persistence in the nutrient-limiting urinary microenvironment.

A model for sepsis prediction after retrograde intrarenal surgery and the use of the preoperative/postoperative white blood cell ratio to predict progression from sepsis to septic shock

OBJECTIVES

To study the predictors of sepsis and progression to septic shock after RIRS; to establish and validate predictive models accordingly.

METHODS

In total, 1220 patients were included in the study during. Eight hundred forty-eight patients were assigned to the development cohort and 372 to the validation cohort according to medical record. Univariate and multivariate logistic regression analyses were used to screen independent risk factors for post-RIRS (Retrograde intrarenal surgery) sepsis and progression to septic shock. Nomogram prediction models were established according to the related independent risk factors. Areas under the receiver operating characteristic curves, calibration plots, and DCA (Decision curve analysis) were used to estimate the discrimination, calibration and clinical usefulness of the prediction model, respectively.

RESULTS

In the development cohort, sepsis occurred in 59 patients, 16 of whom developed septic shock. Multivariate logistic regression analyses showed that the independent risk factors for sepsis after RIRS were preoperative D-J stent implantation, hydronephrosis > 6.25 HU (Hounsfield units), AGR (Albumin/globulin ratio) < 1.95, hs-CRP/Alb (High-sensitivity C-reactive protein/albumin ratio) > 0.060, operating time > 67.5 min, and urinary nitrite positivity. The preoperative/postoperative WBC ratio > 1.5 was an independent risk factor for progression from sepsis to septic shock. In the development cohort, the AUC (Area under curve) for predicting sepsis risk was 0.845, and the AUC for predicting septic shock risk was 0.896; in the validation cohort, the corresponding values were 0.896 and 0.974, respectively. In the development cohort, the calibration test P values in the sepsis and septic shock cohorts, respectively, were 0.921 and 0.817; in the validation cohort, these values were 0.882 and 0.859. DCA of the model in the sepsis and septic shock cohorts showed threshold probabilities of 10-90% in the development cohort and 10-50% and 10-20% in the validation cohort.

CONCLUSION

These individualized nomogram prediction models can improve the early identification of patients at risk for developing sepsis after RIRS or progressing from sepsis to septic shock.

An in vitro bladder model with physiological dynamics: Vesicoureteral reflux alters stent encrustation pattern

In vitro models are indispensable to study the physio-mechanical characteristics of the urinary tract and to evaluate ureteral stent performances. Yet previous models mimicking the urinary bladder have been limited to static or complicated systems. In this study, we designed a simple in vitro bladder model to simulate the dynamics of filling and voiding. The physio-mechanical condition of the model was verified using a pressure-flow test with different bladder outlet obstruction levels, and a reflux test was performed to qualitatively demonstrate the stent associated vesicoureteral reflux (VUR). Finally, the setup was applied with and without the bladder model to perform encrustation tests with artificial urine on commercially available double-J stents, and the volumes of luminal encrustations were quantified using micro-Computed Tomography and image segmentation. Our results suggest that, VUR is an important factor contributing to the dynamics in the upper urinary tract with indwelling stents, especially in patients with higher bladder outlet obstruction levels. The influence of VUR should be properly addressed in future in vitro studies and clinical analyses.

Application, Advancement, and Complication of Ureteral Stent and Encrustation: A Major Complication

Three technological aspects have a significant impact on the functioning of an optimal stent. The substance it is made up of, model or design, and coating of the surface are important areas for research. To give recognition of an ideal stent, it summarizes some essential breakthroughs that occurred. Encrustation is a regular problem that can happen when a ureteral stent is implanted in the urinary tract, and it may be dangerous. The part of the paper covers the mechanism of encrustation, stent management, and the most recent technologies created to solve this problem. Encrustation has a complicated and diverse mechanism that includes the time it stays inside, patient-specific risk factors, controlled film production, formation of biofilm, and deposition of minerals. A number of high-tech advancements in stent substances and coverings/coatings could help to reduce the danger of encrustation of stents. It's critical to determine the amount of encrustation of a stent so that therapy options can be tailored properly. For the care of ureteral stents, which are encrusted, we offer a unique therapeutic protocol. The duration of stent indwelling time has been repeatedly established to be a critical risk factor for the evolution of encrustation. The period of stent indwelling time has consistently been established to be a critical risk element for the evolution of encrustation. Patients who are predisposed to bacteriuria and urinary lithiasis are also predisposed to encrustation. Repeated urinary tract infections, diabetes, and chronic kidney failure are among the factors that might escalate urine bacterial load, which can lead to stent encrustation. Due to the prevalence of ureteral stents in urology, it's critical to keep up to date on the best ways to prevent stent encrustation, recognize high-risk patients, and remove them using multimodal techniques.

Environmental, Microbiological, and Immunological Features of Bacterial Biofilms Associated with Implanted Medical Devices

The spread of biofilms on medical implants represents one of the principal triggers of persistent and chronic infections in clinical settings, and it has been the subject of many studies in the past few years, with most of them focused on prosthetic joint infections. We review here recent works on biofilm formation and microbial colonization on a large variety of indwelling devices, ranging from heart valves and pacemakers to urological and breast implants and from biliary stents and endoscopic tubes to contact lenses and neurosurgical implants. We focus on bacterial abundance and distribution across different devices and body sites and on the role of environmental features, such as the presence of fluid flow and properties of the implant surface, as well as on the interplay between bacterial colonization and the response of the human immune system.

Aberrant blood MALT1 and its relevance with multiple organic dysfunctions, T helper cells, inflammation, and mortality risk of sepsis patients

Background

MALT1 is linked with multiple organic dysfunctions, inflammatory storm, and T helper (Th) cell differentiation. Herein, the current study aimed to investigate the correlation of peripheral blood mononuclear cell (PBMC) MALT1 with Th1 cells, Th17 cells, and prognosis of sepsis patients.

Methods

In general, 78 sepsis patients and 40 health controls (HCs) were enrolled. MALT1 expression was detected in PBMCs from all subjects by RT‐qPCR. Besides, Th1 and Th17 cells were measured in PBMCs from sepsis patients by flow cytometry; interleukin 17A (IL‐17A) and interferon gamma (IFN‐γ) were determined in serum from sepsis patients by ELISA.

Results

MALT1 expression was higher in sepsis patients than HCs (p < 0.001). MALT1 expression was positively correlated with Th17 cells (r_s = 0.291, p = 0.038) and IL‐17A (r_s = 0.383, p = 0.001), but not with Th1 cells (r_s = 0.204, p = 0.151) or IFN‐γ (r_s = 0.175, p = 0.125) in sepsis patients. MALT1 expression was positively correlated with APACHE II score (r_s = 0.275, p = 0.015), C‐reactive protein (CRP) (r_s = 0.257, p = 0.023), and sequential organ failure assessment (SOFA) score (r_s = 0.306, p = 0.006) (MALT1 expression was positively correlated with SOFA respiratory system score (r_s = 0.348, p = 0.002), and SOFA liver score (r_s = 0.260, p = 0.021), but not with SOFA scores in nervous system, cardio vascular system, coagulation, and renal system (all p > 0.05)). MALT1 expression (p = 0.010), Th1 cells (p = 0.010), Th17 cells (p = 0.038), and IL‐17A (p = 0.012), except for IFN‐γ (p = 0.102), elevated in sepsis deaths compared with sepsis survivors.

Conclusion

PBMC MALT1 is highly expressed in sepsis patients with its overexpression associated with multiple organic dysfunctions, elevated Th17 cells, and increased mortality risk.

Ten Steps to Strategic Planning for the Urinary Stents of the Future

The aim of this chapter is to present all the current knowledge related to urinary stents. As well as to describe the future lines of research and improvement that are needed in this field of knowledge. To this end, a decalogue is described in which the main lines of research are addressed, as well as the needs for improvement of urinary stents. This research pathway must begin with an adequate understanding the side effects and complications related to urinary stents. Another very important factor is to describe the proper indication for the use of urinary stents, because if it is possible to correct their use, their adverse effects will be avoided. This is currently complicated by the lack of medical consensus on this issue. It is clear that urology needs a great deal of development of biodegradable biomaterials and coatings, which prevent biofilm formation and stent encrustation. This is one of the most important fields of development for the years to come, due to the obvious hostility of urine to current biomaterials. The development of new and improved stent designs, as well as the ability of stents to deliver drugs into the urinary tract, are also much needed lines of research.

Tumor stent for chronic ureteral obstruction: Which are predictors of stent failure?

PURPOSE

To identify predictors of UROSOFT® tumor stent failure. According to the manufacturer, this reinforced ureteral stent has a maximal dwell time of 6 months. Nonetheless, stent failure may reduce this maximal dwell time.

METHODS

All patients undergoing first-time UROSOFT® tumor stent insertion in our institution between 2010 and 2018 were considered for this retrospective analysis. Primary endpoint was stent failure and defined as premature stent exchange or percutaneous nephrostomy insertion.

RESULTS

182 patients were available for analysis. Median age was 68 years. Causes for tumor stent placement were extrinsic ureteral obstruction in 144 patients (79 %) and intrinsic obstruction in 38 patients (21 %). Tumor stent failure free survival estimates at 1, 2, 3, 4 and 5 months were 89%, 83%, 76%, 65% and 52%, respectively. Patients with stent failure had significantly higher grade of hydronephrosis, higher urinary culture bacterial growth, higher serum WBC, higher CRP and lower eGFR at the time of re-intervention, compared to patients who underwent regular stent exchange. Of all baseline and perioperative parameters, we found bilateral insertion, intrinsic ureteral obstruction, and urinary tract infection (UTI) at time of tumor stent insertion to be significant and independent predictors of stent failure (all p < 0.05).

CONCLUSION

Despite a theoretical maximal dwell time of 6 months, around 50% of all cases are subject to premature stent failure. Predictors of stent failure are bilateral insertion, intrinsic ureteral obstruction, and UTI at the time of tumor stent insertion. Preoperative antibiotic therapy may impact on stent failure rate.

Challenges in the Microbiological Diagnosis of Implant-Associated Infections: A Summary of the Current Knowledge

Implant-associated infections are characterized by microbial biofilm formation on implant surface, which renders the microbiological diagnosis challenging and requires, in the majority of cases, a complete device removal along with a prolonged antimicrobial therapy. Traditional cultures have shown unsatisfactory sensitivity and a significant advance in the field has been represented by both the application of the sonication technique for the detachment of live bacteria from biofilm and the implementation of metabolic and molecular assays. However, despite the recent progresses in the microbiological diagnosis have considerably reduced the rate of culture-negative infections, still their reported incidence is not negligible. Overall, several culture- and non-culture based methods have been developed for diagnosis optimization, which mostly relies on pre-operative and intra-operative (i.e., removed implants and surrounding tissues) samples. This review outlines the principal culture- and non-culture based methods for the diagnosis of the causative agents of implant-associated infections and gives an overview on their application in the clinical practice. Furthermore, advantages and disadvantages of each method are described.

Fluid mechanical modeling of the upper urinary tract

The upper urinary tract (UUT) consists of kidneys and ureters, and is an integral part of the human urogenital system. Yet malfunctioning and complications of the UUT can happen at all stages of life, attributed to reasons such as congenital anomalies, urinary tract infections, urolithiasis and urothelial cancers, all of which require urological interventions and significantly compromise patients' quality of life. Therefore, many models have been developed to address the relevant scientific and clinical challenges of the UUT. Of all approaches, fluid mechanical modeling serves a pivotal role and various methods have been employed to develop physiologically meaningful models. In this article, we provide an overview on the historical evolution of fluid mechanical models of UUT that utilize theoretical, computational, and experimental approaches. Descriptions of the physiological functionality of each component are also given and the mechanical characterizations associated with the UUT are provided. As such, it is our aim to offer a brief summary of the current knowledge of the subject, and provide a comprehensive introduction for engineers, scientists, and clinicians who are interested in the field of fluid mechanical modeling of UUT. This article is categorized under: Cancer > Biomedical Engineering Infectious Diseases > Biomedical Engineering Reproductive System Diseases > Biomedical Engineering.

Does potassium citrate administration change the type and composition of encrusted material on Double-J stent compared to primary stone?

Purpose

To evaluate the effect of potassium citrate administration on the composition of encrusted material on the ureteral stent after Double-J insertion.

Methods

We designed a randomized clinical trial for our study; 65 patients that underwent transurethral lithotripsy and Double-J stent insertion were included in the study after informed consent and divided into two groups. In the first group (33 patients) potassium citrate was prescribed after surgery till stent removal and the second group (32 patients) followed without prescribing this medication. After stent removal, encrusted materials on removed stents were analyzed then the type and composition of encrusted material compared with the primary stone that was removed.

Results

Our results revealed that the type and composition of primary stone and encrusted stone were similar in patients that do not receive potassium citrate (p-value of 0.073, 0.251 and 0.944 for calcium oxalate, uric acid, and calcium phosphate respectively). In patients that taking potassium citrate rate of calcium oxalate (p-value < 0.001) and uric acid (p-value < 0.001) material on encrusted stent significantly decreased compared with the non-intervention group.

Conclusion

Results of this study revealed that taking of potassium citrate after ureteral stent insertion significantly decreases the formation of calcium oxalate and uric acid encrusted material on Double-J stent so it could be recommended for prevention of stent encrustation in patients that primary stone analysis are calcium oxalate and uric acid stone.

Biofilm-Infected Human Clusteroid Three-Dimensional Coculture Platform to Replace Animal Models in Testing Antimicrobial Nanotechnologies

Microbial biofilms are a major concern in wound care, implant devices, and organ infections. Biofilms allow higher tolerance to antimicrobial drugs, can impair wound healing, and potentially lead to sepsis. There has been a recent focus on developing novel nanocarrier-based delivery vehicles to enhance the biofilm penetration of traditional antibacterial drugs. However, a feasible in vitro human skin model to mimic the biofilm formation and its treatment for clearance have not yet been reported. This study describes the benefits of using an innovative bacterial biofilm-infected keratinocyte clusteroid model for the first time. It paves a new way for testing innovative nanomedicine delivery systems in a rapid and reproducible way on a realistic human cell-based platform, free of any animal testing. Herein, we have developed a novel composite 3D biofilm/human keratinocyte clusteroid coculture platform, which was used to measure biofilm clearance efficiency of nanoparticle (NP)-based therapeutics. We tested this model by treating the biofilm-infected 3D coculture layers by a ciprofloxacin-loaded Carbopol nanogel particles, surface-functionalized by the cationic protease Alcalase. We measured the antibacterial efficiency of the NP treatment on clearing Staphylococcus aureus and Pseudomonas aeruginosa biofilms on the 3D keratinocyte clusteroid/biofilm coculture model. Our experiments showed that these bacteria can infect the 3D layer of keratinocyte clusteroids and produce a stable biofilm. The biofilms were efficiently cleared by treatment with a formulation of 0.0032 wt % ciprofloxacin-loaded in 0.2 wt % Carbopol NPs surface-functionalized with 0.2 wt % Alcalase. Taken together, these promising results demonstrate that our coculture model can be exploited as a novel platform for testing the biofilm-eliminating efficiency of various NP formulations emulating skin and wound infections and could have wider applicability to replace animal models in similar experiments. This 3D cell culture-based platform could help in developing and testing of more effective antibacterial agents for clinical applications of antiplaque dental treatments, implants, infection control, and wound dressings.

Epidemiology and risk factors for ureteral stent-associated urinary tract infections in non-transplanted renal patients: a systematic review of the literature

PURPOSE

Pathophysiology and risk factors for Ureteral Stent-Associated Urinary Tract Infection (USAUTI) have been poorly investigated. This situation results in highly diverse practices regarding USAUTI prevention, diagnosis and treatment. The aim of the present study was to describe the epidemiology and risk factors for USAUTI in non-transplanted patients.

METHODS

We conducted a systematic literature review based on a comprehensive PubMed® bibliographic strategy, between October 1998 and March 2020. The methodological quality of the studies included was analyzed according to dedicated grids. The main endpoints were the correlation between different potential risk factors and infection ureteral stent-associated urinary tract infection or colonization rate. Conclusions and their level of evidence were reported on the basis of a critical analysis of the best available scientific evidence. This work has been submitted to a national review, which enabled the potentially divergent opinions of experts to be collected, thereby ensuring adequate quality of data.

RESULTS AND CONCLUSION

Twenty-six studies out of the 505 articles identified, were included in the final analysis. Staphylococcus spp, E. coli, Klebsiella spp, Pseudomona aeruginosa, Enterococcus spp. and Candida spp. were the microorganisms most often responsible for asymptomatic bacteriuria (ABU) or USAUTI. Longer indwelling time, diabetes mellitus, female gender, chronic renal failure, diabetic nephropathy and cancer were identified as risk factors for ABU and ureteral stent colonization. No specific risk factor for UTI was identified in the literature studied. A causal relationship between ureteral stent colonization and USAUTI or urosepsis remains to be demonstrated.

Expression of Inflammatory Factors in Critically Ill Patients with Urosepticemia and the Imaging Analysis of the Severity of the Disease

Urine sepsis is a complex inflammatory response of the body to infection with a high fatality rate. It is one of the main causes of death in noncardiovascular intensive care units. Nevertheless, in daily clinical practice, early sepsis is often not detected. In this paper, discharged cases of urinary sepsis from the Department of Urology and Critical Care Medicine of a university hospital were collected as the observation group, and common urinary tract infection cases were selected as the control group. We sorted and summarized the discharged case information of the observation group and the control group. The results of the study showed that, after renal pelvis perfusion, the expression of HMGB1 protein and mRNA increased, and the expression of TLR4 increased; inhibiting HMGB1 can reduce the expression of inflammatory factors caused by perfusion and reduce the infiltration of neutrophils and macrophages caused by perfusion. In addition, r HMGB1 treatment can promote the expression of inflammatory factors caused by perfusion and aggravate the infiltration of neutrophils and macrophages caused by perfusion. We found that inhibition of HMGB1 can inhibit the expression of TLR4/My D88 signaling molecules and r HMGB1 treatment can enhance the expression of TLR4/My D88 signaling molecules.

Antimicrobial Peptides Grafted onto a Plasma Polymer Interlayer Platform: Performance upon Extended Bacterial Challenge

To combat infections on biomedical devices, antimicrobial coatings have attracted considerable attention, including coatings comprising naturally occurring antimicrobial peptides (AMPs). In this study the aim was to explore performance upon extended challenge by bacteria growing in media above samples. The AMPs LL37, Magainin 2, and Parasin 1 were selected on the basis of well-known membrane disruption activity in solution and were covalently grafted onto a plasma polymer platform, which enables application of this multilayer coating strategy to a wide range of biomaterials. Detailed surface analyses were performed to verify the intended outcomes of the coating sequence. Samples were challenged by incubation in bacterial growth media for 5 and 20 h. Compared with the control plasma polymer surface, all three grafted AMP coatings showed considerable reductions in bacterial colonization even at the high bacterial challenge of initial seeding at 1 × 107 CFU, but there were increasing numbers of dead bacteria attached to the surface. All three grafted AMP coatings were found to be non-toxic to primary fibroblasts. These coatings thus could be useful to produce antibacterial surface coatings for biomaterials, though possible consequences arising from the presence of dead bacteria need to be studied further, and compared to non-fouling coatings that avoid attachment of dead bacteria.

Infectious Disease Complications in Patients with Cancer

Critically ill patients with cancer are vulnerable to infections because of the underlying malignancy, tumor-directed therapy, immunosuppression, breaches in mucosa or skin, malnutrition, and other factors. Neutropenia remains the most important risk factor for infection. Infectious complications occurring in critically ill patients with cancer can affect the bloodstream, lungs, gastrointestinal tract, central nervous system, urinary tract, and the skin. Pneumonias are the leading cause of infection in patients with cancer admitted to the intensive care unit. Consideration of opportunistic pathogens in the differential diagnosis is important in patients with impaired cellular and/or humoral immunity or compromised splenic function.

Predictors of urosepsis in struvite stone patients after percutaneous nephrolithotomy

Purpose

This study aims to identify clinical factors that may predispose struvite stone patients to urosepsis following percutaneous nephrolithotomy (PCNL).

Materials and Methods

A retrospective review was conducted on patients who received PCNL for struvite stones. The Systemic Inflammatory Response Syndrome (SIRS) criteria and quick-Sepsis Related Organ Failure Assessment (q-SOFA) criteria were used to identify patients who were at an increased risk for urosepsis. Statistical analysis was performed using Fisher's exactness test, Wilcoxon rank test, and logistic regression.

Results

Chart review identified 99 struvite stone patients treated with PCNL. Post-operatively, 40 patients were SIRS positive (≥2 criteria) and/or q-SOFA positive (score ≥2). Using SIRS as an approximation for urosepsis, longer operative times (p<0.001), higher pre-operative white blood cell counts (p=0.01), greater total stone surface area (p<0.0001), and pre-operative stenting (OR, 5.75; p=0.01) were identified as independent risk factors for urosepsis. Multivariate analysis demonstrated pre-operative stenting (OR, 1.46; p=0.01) to be a risk factor. With q-SOFA, univariable analysis found that antibiotic use within 3 months prior to a PCNL (OR, 4.44; p=0.04), medical comorbidities (OR, 4.80; p=0.02), longer operative times (p<0.001), lengthier post-operative hospitalization (p<0.01), and greater total stone surface area (p<0.0001) were risk factors for urosepsis. Multivariate analysis revealed that bladder outlet obstruction (OR, 2.74; p<0.003) and pre-operative stenting (OR, 1.27; p=0.01) significantly increased odds of being q-SOFA positive.

Conclusions

Several risk factors for urosepsis following PCNL for struvite stones have been identified. These risk factors should be taken into consideration in peri-operative care to mitigate the risks of urosepsis.

In vivo assessment of biodegradable magnesium alloy ureteral stents in a pig model

Today, ureteral stent technology is making progress towards the reduction of complications and patient discomfort. Therefore, magnesium alloys have become excellent candidate materials for manufacturing ureteral stents due to their biodegradability and antibacterial activity. Built on our previous work on biodegradable magnesium alloys, this article reports a semisolid rheo-formed magnesium implant that displays degradability and biocompatibility in vivo, and feasibility as ureteral stents in a pig model. Refined non-dendritic microstructure was observed in the rheo-formed alloy, whose grain size and shape factor were ca. 25.2 μm and ca. 1.56 respectively. Neither post-interventional inflammation nor pathological changes were observed in the urinary system during the implantation period of 14 weeks, and the degradation profile (14 weeks) meets the common requirement for the indwelling time of ureteral stents (8 to 16 weeks). Furthermore, histopathological observation and urinalysis results confirmed that the alloy had significantly higher antibacterial activity than the medical-grade stainless steel control. To our knowledge, this is the first in vivo study of biodegradable magnesium alloy as urinary implants in large animal models. Our results demonstrate that magnesium alloys may be a reasonable option for manufacturing biodegradable ureteral stents.

Study on risk factors, bacterial species, and drug resistance of acute pyelonephritis associated with ureteral stent after percutaneous nephrolithotomy

The purpose of this study is to explore the risk factors, bacterial species, and drug resistance of acute pyelonephritis (AP) associated with ureteral stent after percutaneous nephrolithotomy (PCNL) and to provide reference for clinical intervention. The clinical data of 415 patients with indwelling ureteral stent after PCNL from December 2016 to May 2019 were analyzed retrospectively. The patients were divided into infection group (n = 54) and non-infection group (n = 361) according to whether patients had AP. Patients' clinical data, blood and urine bacterial culture, and drug sensitivity were collected and analyzed. The incidence of AP associated with ureteral stent after PCNL was 13.01% and diabetes mellitus (P = 0.001), postoperative stone residue (P = 0.002), urinary leucocytes ≥ 100/HP (P = 0.018), positive urine culture results (P = 0.001), ureteral stent retention time ≥ 8 weeks (P = 0.004), and high S.T.O.N.E. score (P = 0.014) are independent risk factors for it. Escherichia coli (40.54%, 47.82%), Klebsiella pneumoniae (16.21%, 15.21%), Pseudomonas aeruginosa (10.81%, 4.34%), Enterococcus faecalis (21.6%, 19.56%), and epidermis Staphylococci (10.81%, 13.33%) are the main pathogens in blood and urine. The main sensitive drugs of pathogenic bacteria are imipenem, meropenem, tigecycline, piperacillin/tazobactam, ceftazidime, linezolid, teicoplanin, levofloxacin, vancomycin, tigecycline, etc., while levofloxacin, norfloxacin, penicillin G, first, and second-generation cephalosporins showed a strong drug resistance rate (> 70%). This study found that diabetes, postoperative stone residuals, urinary leukocytes ≧ 100 cells/HP, positive urine culture results, ureteral stent indwelling time ≧ 8 weeks, and high S.T.O.N.E. score were independent of AP associated with ureteral stent after PCNL risk factors and Escherichia coli is the main pathogenic bacteria and shows drug resistance.

Predictive value of the sequential organ failure assessment (SOFA) score for prognosis in patients with severe acute ischemic stroke: a retrospective study

OBJECTIVE

To identify the risk factors for early death and determine the predictive value of the sequential organ failure assessment (SOFA) score for prognosis of severe acute ischemic stroke (AIS).

METHODS

A total of 110 patients with severe AIS were enrolled and divided into the non-survivor (n = 34) and survivor groups (n = 76). Logistic regression analysis was conducted to identify risk factors for early death, while the receiver operator characteristic (ROC) curve was used to determine the predictive effect of the SOFA score on prognosis.

RESULTS

Logistic regression analysis showed that urinary tract infection (odds ratio [OR] = 17.364, 95% confidence interval [CI]: 1.903-158.427), mechanical ventilation (OR = 1.754, 95% CI: 1.648-2.219), and osmotic therapy (OR = 2.835, 95% CI: 1.871-5.102) were significantly correlated with early death of severe AIS. ROC curve analysis of the area under the curve after hospitalization showed that the maximum SOFA and ΔSOFA scores exceeded 0.7.

CONCLUSION

Our study shows that urinary tract infection, mechanical ventilation, and osmotic therapy are risk factors for early death of severe AIS. The SOFA score has good predictive value for prognosis of severe AIS. These findings may provide a guideline for improving clinical outcome.

Biofouling and me: My Stockholm syndrome with biofilms

Biofouling is the undesired deposition and growth of microorganisms on surfaces, forming biofilms. The definition is subjective and operational: not every biofilm causes biofouling - only if a given a subjective "threshold of interference" is exceeded, biofilms cause technical or medical problems. These range from the formation of slime layers on ship hulls or in pipelines, which increase friction resistance, to separation membranes, on which biofilms increase hydraulic resistance, to heat exchangers where they interfere with heat transport to contamination of treated water by eroded biofilm cells which may comprise hygienically relevant microorganisms, and, most dangerous, to biofilms on implants and catheters which can cause persistent infections. The largest fraction of anti-fouling research, usually in short-term experiments, is focused on prevention or limiting primary microbial adhesion. Intuitively, this appears only logical, but turns out mostly hopeless. This is because in technical systems with open access for microorganisms, all surfaces are colonized sooner or later which explains the very limited success of that research. As a result, the use of biocides remains the major tool to fight persistent biofilms. However, this is costly in terms of biocides, it stresses working materials, causes off-time and environmental damage and it usually leaves large parts of biofilms in place, ready for regrowth. In order to really solve biofouling problems, it is necessary to learn how to live with biofilms and mitigate their detrimental effects. This requires rather an integrated strategy than aiming to invent "one-shot" solutions. In this context, it helps to understand the biofilm way of life as a natural phenomenon. Biofilms are the oldest, most successful and most widely distributed form of life on earth, existing even in extreme environments and being highly resilient. Microorganisms in biofilms live in a self-produced matrix of extracellular polymeric substances (EPS) which allows them to develop emerging properties such as enhanced nutrient acquisition, synergistic microconsortia, enhanced tolerance to biocides and antibiotics, intense intercellular communication and cooperation. Transiently immobilized, biofilm organisms turn their matrix into an external digestion system by retaining complexed exoenzymes in the matrix. Biofilms grow even on traces of any biodegradable material, therefore, an effective anti-fouling strategy comprises to keep the system low in nutrients (good housekeeping), employing low-fouling, easy-to-clean surfaces, monitoring of biofilm development, allowing for early intervention, and acknowledging that cleaning can be more important than trying to kill biofilms, because cleaning does not cut the nutrient supply of survivors and dead biomass serves as an additional carbon source for "cannibalizing" survivors, supporting rapid after growth. An integrated concept is presented as the result of a long journey of the author through biofouling problems.

Detection of microbial colonization of the urinary tract of patients prior to secondary ureterorenoscopy is highly variable between different types of assessment: results of a prospective observational study

This study compares the findings of different detection methods for microorganisms in patients with ureteral stents undergoing secondary ureterorenoscopy including the use of a novel validated examination pipeline for biofilms on ureteral stents. Of the included 94 patients, 21.3% showed bacteriuria in preoperative urine cultures. Intraoperative urine culture showed bacteriuria in four (4.3%) of the patients. Stent biofilm cultures were positive in 12.9% and qPCR detected bacterial DNA in 18.1%. The findings of the different examinations were poorly correlated with each other. Detection of microorganisms in the urinary tract of patients with indwelling ureteral stents is highly dependent on timing (i.e. pre- vs intraoperative) and method of assessment. Preoperative routine urine cultures are not predictive for intraoperative urine- and stent culture. These results cast doubt on the clinical relevance of enterococcal species, staphylococci, and streptococci if identified preoperatively prior to stent removal. The timing of oral preoperative antibiotic prophylaxis might need to be reconsidered.