Infection responsive coatings to reduce biofilm formation and encrustation of urinary catheters.

AIMS: The care of patients undergoing long-term urethral catheterization is frequently complicated by Proteus mirabilis infection. This organism forms dense, crystalline biofilms, which block catheters leading to serious clinical conditions. However, there are currently no truly effective approaches to control this problem. Here, we describe the development of a novel theranostic catheter coating, to simultaneously provide early warning of blockage, and actively delay crystalline biofilm formation. METHODS AND RESULTS: The coating comprises of a pH sensitive upper polymer layer (poly(methyl methacrylate-co-methacrylic acid); Eudragit S 100®) and a hydrogel base layer of poly(vinyl alcohol), which is loaded with therapeutic agents (acetohydroxamic acid or ciprofloxacin hydrochloride) and a fluorescent dye, 5(6)-carboxyfluorescein (CF). The elevation of urinary pH due to P. mirabilis urease activity results in the dissolution of the upper layer and release of cargo agents contained in the base layer. Experiments using in vitro models, which were representative of P. mirabilis catheter-associated urinary tract infections, demonstrated that these coatings significantly delay time taken for catheters to block. Coatings containing both CF dye and ciprofloxacin HCl were able to provide an average of ca. 79 h advanced warning of blockage and extend catheter lifespan ca. 3.40-fold. CONCLUSIONS: This study has demonstrated the potential for theranostic, infection-responsive coatings to form a promising approach to combat catheter encrustation and actively delay blockage.

Pathogenesis of Proteus mirabilis in Catheter-Associated Urinary Tract Infections.

Proteus mirabilis (PM) is a Gram-negative rod-shaped bacterium and widely exists in the natural environment, and it is most noted for its swarming motility and urease activity. PM is the main pathogen causing complicated urinary tract infections (UTIs), especially catheter-associated urinary tract infections. Clinically, PM can form a crystalline biofilm on the outer surface and inner cavity of the urethral indwelling catheter owing to its ureolytic biomineralization. This leads to catheter encrustation and blockage and, in most cases, is accompanied by urine retention and ascending UTI, causing cystitis, pyelonephritis, and the development of bladder or kidney stones, or even fatal complications such as septicemia and endotoxic shock. In this review, we discuss how PM is mediated by a catheter into the urethra, bladder, and then rose to the kidney causing UTI and the main virulence factors associated with different stages of infection, including flagella, pili or adhesins, urease, hemolysin, metal intake, and immune escape, encompassing both historical perspectives and current advances.

Spontaneous extrusion of renal calculi presenting as a retroperitoneal abscess.

Spontaneous extrusion of a kidney stone is an extremely rare event with few reported cases. We present the unusual case of a 62-year-old female who presented with worsening of fever and flank pain over a 5 day period. Imaging revealed retroperitoneal and abdominal wall abscesses that upon evaluation of prior imaging were attributed to spontaneously extruded kidney stones. Prior reports suggest surgical exploration and extraction is the preferred treatment option for extruded renal calculi. Based on the experience presented here, conservative management may be an attractive first-line treatment option for patients with extruded renal stones and associated retroperitoneal abscesses.

Risk of infection in patients undergoing urologic surgery based on the presence of asymptomatic bacteriuria: A prospective study.

BACKGROUND: Treatment of asymptomatic bacteriuria (ASB) is recommended in pregnant women and prior to urologic procedures with anticipated mucosal disruption. However, there is still insufficient evidence of the usefulness of treating ASB prior to urologic procedures. Therefore, the aim of this study was to ascertain the risk of infections in patients undergoing urologic surgery based on the presence of ASB. METHODS: We conducted a cohort study among patients undergoing urologic surgery at a single center located in Medellín, Colombia. All patients were screened for ASB prior to their procedures. Patients were evaluated for the development of any postoperative infectious complications for up to 30 days after the procedure. RESULTS: A total of 149 patients were included in this cohort. Incidence of ASB was 14.8%. Thirteen patients (8.72%) developed infectious complications: 3 (13.64%) with ASB and 10 (7.87%) without ABS. Factors associated with postoperative infectious complications included urologic cancers (hazard ratio [HR], 5.26; 95% confidence intervals [CI], 1.24-22.37), urologic interventions in the preceding 3 months (HR, 3.72; 95% CI, 1.02-13.51), and use of antibiotics 3 months prior to surgery (HR, 3.83; 95% CI, 1.01-15.49). Presence of ASB was not associated with postsurgical infectious complications (HR, 1.02; 95% CI, 0.26-3.96). CONCLUSIONS: There was no association between ASB and postoperative infectious complications. There were other factors associated with infectious complications, such as urologic cancer, previous history of urologic manipulation, and antibiotic use.

Polymicrobial bacterial pericarditis and cardiac tamponade caused by pericardial penetration of an adjustable gastric band.

We describe a case of polymicrobial bacterial pericarditis with Klebsiella pneumoniae and Proteus mirabilis, caused by pericardial penetration of the tip of the catheter of a laparoscopic adjustable gastric band (LAGB). The patient developed a cardiac tamponade, and subsequently emergency pericardiocentesis was performed. Analysis of earlier CT scans showed that the tip of the catheter had migrated through the liver and through the diaphragm into the pericardium, and was in contact with the myocardium. After stabilisation he was operated to remove the LAGB. In this case report, we describe the chain of events that led to the polymicrobial pericarditis-a complication of LAGB placement that to our knowledge has thus far never been reported. We furthermore present a detailed literature review of all published cases of polymicrobial pericarditis and its causes.

Prostatic abscess: a rare complication of staghorn calculi.

A staghorn calculus is a calculus accommodating the majority of a renal calyx extending into the renal pelvis. A conservative approach to its treatment may lead to high morbidity and mortality rates. Such morbidity usually manifests with renal failure, obstructed upper urinary tractand/or life-threatening sepsis. Prostatic abscesses have never been associated with staghorn calculi in the literature. We report a case of a 70-year-old man who presented with sepsis, which was found to originate from a complex prostatic abscess. The patient had no history of urinary tract infections or risk factors. The authors believe that the incidentally identified staghorn calculi promoted the growth of Proteus mirabilis which led to the development of the prostatic abscess. The patient underwent a transurethral resection and drainage of the abscess following a failed course of antibiotic therapy. This case also highlights the paucity of guidelines available in treating prostatic abscesses.

The use of Twitter to facilitate sharing of clinical expertise in urology.

The use of social media in the urologic community is common and increasing. Although the potential benefits of platforms like Twitter have been described in the literature, the use of social media in the clinical context of Urology has not been explored.In this case report, we describe how we used Twitter to share ideas about the clinical management of a complex urologic patient. By posting a clinical scenario, a timely discussion was generated with global participation and expert suggestions. This knowledge was applied to the surgical management of a patient with positive clinical outcomes.The ability of Twitter to facilitate rapid communication with a wide network of contributors makes it a potentially useful tool for clinical decision making. Care must be taken to ensure patient confidentiality and caution used appropriately when evaluating the sources and content of the clinical information shared.

Chromosomal Amplification of the blaOXA-58 Carbapenemase Gene in a Proteus mirabilis Clinical Isolate.

Horizontal gene transfer may occur between distantly related bacteria, thus leading to genetic plasticity and in some cases to acquisition of novel resistance traits. Proteus mirabilis is an enterobacterial species responsible for human infections that may express various acquired ß-lactam resistance genes, including different classes of carbapenemase genes. Here we report a Proteus mirabilis clinical isolate (strain 1091) displaying resistance to penicillin, including temocillin, together with reduced susceptibility to carbapenems and susceptibility to expanded-spectrum cephalosporins. Using biochemical tests, significant carbapenem hydrolysis was detected in P. mirabilis 1091. Since PCR failed to detect acquired carbapenemase genes commonly found in Enterobacteriaceae, we used a whole-genome sequencing approach that revealed the presence of blaOXA-58 class D carbapenemase gene, so far identified only in Acinetobacter species. This gene was located on a 3.1-kb element coharboring a blaAmpC-like gene. Remarkably, these two genes were bracketed by putative XerC-XerD binding sites and inserted at a XerC-XerD site located between the terminase-like small- and large-subunit genes of a bacteriophage. Increased expression of the two bla genes resulted from a 6-time tandem amplification of the element as revealed by Southern blotting. This is the first isolation of a clinical P. mirabilis strain producing OXA-58, a class D carbapenemase, and the first description of a XerC-XerD-dependent insertion of antibiotic resistance genes within a bacteriophage. This study revealed a new role for the XerC-XerD recombinase in bacteriophage biology.

Proteus mirabilis abscess involving the entire neural axis.

Intramedullary spinal cord abscesses are rare and potentially devastating lesions usually associated with other infective processes such as bacterial endocarditis, or pulmonary or urogenital infection. We describe a 2-year-old girl who presented with an infected dermal sinus leading to an intraspinal abscess. This abscess eventually spread and involved the entire neural axis leaving her quadriparetic. Drainage of the abscess resulted in recovery and the child regained normal function of her limbs. To our knowledge this is the first documented case of an intramedullary abscess involving the entire neural axis.

A high throughput, minimally invasive, ultrasound guided model for the study of catheter associated urinary tract infections and device encrustation in mice.

PURPOSE: Catheter associated urinary tract infections are one of the most common health care associated infections. The condition is frequently complicated by encrustation, which blocks the catheter lumen. Preclinical research is limited by the lack of relevant high throughput and cost-effective animal models. Current models are restricted to female mice, associated with major transurethral loss of catheter materials during micturition, highly invasive and complex. We present an ultrasound guided, minimally invasive model that enables catheter associated urinary tract infection and catheter encrustation studies in each mouse gender. MATERIALS AND METHODS: Catheter segments (4 mm) were implanted in murine bladders percutaneously in 15 males and 5 females, and transurethrally in 15 females using the Seldinger technique under ultrasound guidance. Proteus mirabilis was instilled intraluminally. Catheter encrustation was monitored by ultrasound. Bacteria were quantified in urine, and catheters and encrustation were analyzed on day 6 or 21. RESULTS: Percutaneous and transurethral catheter implantations were performed in a mean ± SE 3.6 ± 0.8 vs 2.5 ± 0.5 minutes in all mice. Ultrasound confirmed that 100% and 66% of implanted catheters, respectively, remained indwelling during the study period. Catheter encrustation developed in P. mirabilis infected urine 48 hours after instillation and an increase with time was detected by ultrasound. Fourier transform spectroscopy of the encrustation confirmed a typical struvite spectrum. Control catheters remained sterile during 21 days. CONCLUSIONS: Our minimally invasive, reproducible percutaneous technique is suitable for studying catheter associated urinary tract infection in each gender. Infecting urine with P. mirabilis generates a preclinical model of catheter encrustation within 3 days. The progression of encrustation can be monitored in vivo by ultrasound, making this image based model suitable for assessing novel antibacterial and anti-encrustation therapies.

Clinical complications of urinary catheters caused by crystalline biofilms: something needs to be done.

This review is largely based on a previous paper published in the journal Spinal Cord. The care of many patients undergoing long-term bladder catheterization is complicated by encrustation and blockage of their Foley catheters. This problem stems from infection by urease-producing bacteria, particularly Proteus mirabilis. These organisms colonize the catheter forming an extensive biofilm; they also generate ammonia from urea, thus elevating the pH of urine. As the pH rises, crystals of calcium and magnesium phosphates precipitate in the urine and in the catheter biofilm. The continued development of this crystalline biofilm blocks the flow of urine through the catheter. Urine then either leaks along the outside of the catheter and the patient becomes incontinent or is retained causing painful distension of the bladder and reflux of urine to the kidneys. The process of crystal deposition can also initiate stone formation. Most patients suffering from recurrent catheter encrustation develop bladder stones. P. mirabilis establishes stable residence in these stones and is extremely difficult to eliminate from the catheterized urinary tract by antibiotic therapy. If blocked catheters are not identified and changed, serious symptomatic episodes of pyelonephritis, septicaemia and endotoxic shock can result. All types of Foley catheters including silver- or nitrofurazone-coated devices are vulnerable to this problem. In this review, the ways in which biofilm formation on Foley catheters is initiated by P. mirabilis will be described. The implications of understanding these mechanisms for the development of an encrustation-resistant catheter will be discussed. Finally, the way forward for the prevention and control of this problem will be considered.

Abdominal wall necrotising fasciitis due to dislodged percutaneous endoscopic gastrostomy tube.

Accessing the stomach via a percutaneous endoscopic gastrostomy (PEG) tube is the preferred (and sometimes the only) method for providing enteral nutritional support in disabled patients. However, it is associated with serious and potentially lethal complications which must be completely recognised by physicians, by nurses and especially by radiologists. Abdominal wall necrotising fasciitis of a dislodged or leaking PEG tube could be a lethal complication. We present a case of a 74-year-old bed bound woman who was admitted to our hospital with fever and abdominal pain. On presentation, the patient's temperature was 36°C and laboratory tests showed leucocytosis. Physical examination revealed extensive redness of the abdominal wall, diffuse tenderness of the abdomen and yellowish discharge around the gastrostomy.

Cutaneo-pericardial fistula after transapical aortic valve implantation.

Transcatheter aortic valve implantation (TAVI) represents a therapeutic option of increasing impact for the treatment of high-risk patients with symptomatic, severe aortic valve stenosis. We report here the case of an 86-year old patient with a cutaneo-pericardial fistula after a transapical TAVI procedure.

Complications of chronic suppurative otitis media: a left otogenic brain abscess and a right mastoid fistula.

Otogenic brain abscess and postauricular fistula are complications of chronic suppurative otitis media. We describe a rare case of bilateral chronic suppurative otitis media that caused a left temporal lobe abscess and a right mastoid fistula.

Fournier's gangrene in a child with congenital genitourinary anomalies.

Fournier's gangrene is a rare urologic emergency in childhood that requires prompt diagnosis to deliver definitive and supportive care. Host susceptibility risk factors differ between adult and pediatric age groups with affected children usually otherwise systemically healthy. We present a case of Fournier's gangrene in a 2-year-old, from a genitourinary source of sepsis secondary to previously unreported genitourinary anatomical anomalies of congenital buried penis and hypospadias. Illustrative applied anatomy identifies the pathogenesis of this case, aiding recognition and understanding of this rapidly progressive and destructive pathology.

Complications of inadvertent filtering blebs after cataract extraction.

UNLABELLED: We report 2 cases of inadvertent filtering blebs that developed vision-threatening complications many years after uneventful cataract extraction with scleral incisions. These inadvertent blebs can create complications similar to the intentionally produced blebs from trabeculectomy surgery; thus, follow-up and management should be handled in a similar manner. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.