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A medical tool is a general instrument intended for use in the prevention, diagnosis, and treatment of diseases in humans or other animals. Nowadays, sensors are widely employed in medical tools to analyze or quantify disease‐related parameters for the diagnosis and monitoring of patients' diseases. Recent explosive advancements in sensor technologies have extended the integration and application of sensors in medical tools by providing more versatile in vivo sensing capabilities. These unique sensing capabilities, especially for medical tools for surgery or medical treatment, are getting more attention owing to the rapid growth of minimally invasive surgery. In this review, recent advancements in sensor‐integrated medical tools are presented, and their necessity, use, and examples are comprehensively introduced. Specifically, medical tools often utilized for medical surgery or treatment, for example, medical needles, catheters, robotic surgery, sutures, endoscopes, and tubes, are covered, and in‐depth discussions about the working mechanism used for each sensor‐integrated medical tool are provided. [ABSTRACT FROM AUTHOR]

The antibiotic resistances emerged in uropathogens lead to accumulative treatment failure and recurrent episodes of urinary tract infection (UTI), necessitating more innovative therapeutics to curb UTI before systematic infection. In the current study, the combination of amikacin and nitrofurantoin is found to synergistically eradicate Gram‐negative uropathogens in vitro and in vivo. The mechanistic analysis demonstrates that the amikacin, as an aminoglycoside, induced bacterial envelope stress by introducing mistranslated proteins, thereby constitutively activating the cpxA/R two‐component system (Cpx signaling). The activation of Cpx signaling stimulates the expression of bacterial major nitroreductases (nfsA/nfsB) through soxS/marA regulons. As a result, the CpxA/R‐dependent nitroreductases overexpression generates considerable quantity of lethal reactive intermediates via nitroreduction and promotes the prodrug activation of nitrofurantoin. As such, these actions together disrupt the bacterial cellular redox balance with excessively‐produced reactive oxygen species (ROS) as "Domino effect", accelerating the clearance of uropathogens. Although aminoglycosides are used as proof‐of‐principle to elucidate the mechanism, the synergy between nitrofurantoin is generally applicable to other Cpx stimuli. To summarize, this study highlights the potential of aminoglycoside‐nitrofurantoin combination to replenish the arsenal against recurrent Gram‐negative uropathogens and shed light on the Cpx signaling‐controlled nitroreductase as a potential target to manipulate the antibiotic susceptibility. [ABSTRACT FROM AUTHOR]

Bacterial infections cause serious illnesses that are treated with antibiotics. Currently used methods for detecting bacterial antibiotic susceptibility consume 48–72 h, leading to overuse of antibiotics. Thus, many bacterial species have acquired resistance to a broad range of available antibiotics. There is an urgent need to develop efficient methods for rapid determination of bacterial susceptibility to antibiotics. The combination of machine learning and Fourier‐transform infrared (FTIR) spectroscopy has generated a promising diagnostic approach in medicine and biology. Our main goal is to examine the potential of FTIR spectroscopy to determine the susceptibility of urinary tract infection‐Proteus mirabilis to a specific range of antibiotics, within about 20 min after 24 h culture and identification. We measured the infrared spectra of 489 different P. mirabilis isolates and used random forest to analyze this spectral database. A classification success rate of ~84% was achieved in differentiating between the resistant and sensitive isolates based on their susceptibility to ceftazidime, ceftriaxone, cefuroxime, cefuroxime axetil, cephalexin, ciprofloxacin, gentamicin, and sulfamethoxazole antibiotics in a time span of 24 h instead of 48 h. [ABSTRACT FROM AUTHOR]

Superhydrophobic biological fluid‐repellent surfaces (SBFRSs) have attracted great attention in the treatment of blood and urine‐related diseases because of their unique wettability and compatibility, which creates a new path for the development of medical apparatus and instruments, and are expected to create advances in various fields. Here, this review provides an up‐to‐date summary of research progress on the repellent mechanism and application of SBFRSs. The underlying physical and chemical principles for designing superhydrophobic surfaces are first introduced. Then, the dialectical influences of solid‐liquid interactions between superhydrophobic surfaces and biological fluids on the wettability and compatibility are emphatically expounded. Subsequently, attention is drawn to the recent applications of SBFRSs in biomedical fields, such as surgical medical apparatus, implant materials, extracorporeal circulation devices, and biological fluid detection. Finally, the outlook and challenges in terms of employing SBFRSs are also discussed. This review is expected to provide a comprehensive guidance for the preparation of SBFRSs with compatibility and long‐term superhydrophobic stability that is closely related to clinical applications. [ABSTRACT FROM AUTHOR]

Due to the continuous rise in biofilm‐related infections, biofilms seriously threaten human health. The formation of biofilms makes conventional antibiotics ineffective and dampens immune clearance. Therefore, it is important to understand the mechanisms of biofilm formation and develop novel strategies to treat biofilms more effectively. This review article begins with an introduction to biofilm formation in various clinical scenarios and their corresponding therapy. Established biofilm models used in research are then summarized. The potential targets which may assist in the development of new strategies for combating biofilms are further discussed. The novel technologies developed recently for the prevention and treatment of biofilms including antimicrobial surface coatings, physical removal of biofilms, development of new antimicrobial molecules, and delivery of antimicrobial agents are subsequently presented. Finally, directions for future studies are pointed out. [ABSTRACT FROM AUTHOR]

Objective To test the recommendation that to avoid the complications of long-term indwelling bladder catheterization (e.g. encrustation and blockage by crystalline Proteus mirabilis biofilms) patients should drink cranberry juice. Materials and methods Urine was collected from groups of volunteers who had drunk up to 2 × 500 mL of cranberry juice or water within an 8-h period. Laboratory models of the catheterized bladder were supplied with urine from these groups and inoculated with P. mirabilis. After incubation for 24 or 48 h, the extent of catheter encrustation was determined by chemical analysis for calcium and magnesium. Encrustation was also visualized by scanning electron microscopy. Results The amounts of calcium and magnesium recovered from catheters incubated in urine pooled from individuals who had drunk 500 mL of cranberry juice was not significantly different from that on catheters incubated in pooled urine from control subjects who had drunk 500 mL of water. However, there was significantly less encrustation (P = 0.007) on catheters from models receiving urine from volunteers who had drunk 2 × 500 mL of water than on catheters incubated in models supplied with urine from volunteers who had drunk 2 × 500 mL of cranberry juice. The amounts of encrustation on these two groups of catheters were also significantly less than that on catheters incubated in models supplied with urine from volunteers who had not supplemented their normal fluid intake. (P < 0.001). Experiments in the models using artificial urine showed that increasing the low fluid intake (720 mL/24 h) characteristic of many patients undergoing long-term catheterization by factors of three and six, significantly (P < 0.01) reduced the amounts of calcium and magnesium that formed on catheters. At a simulated fluid intake of 720 mL/24 h, catheters blocked with encrustation after a mean of 42.5 h, while those supplied with urine produced from an intake of 4320 mL/24 h, drained freely for > 10 days. Conclusion In this in vitro study, drinking cranberry juice did not produce urine that was inhibitory to the development of crystalline catheter-blocking P. mirabilis biofilms. The important factor in preventing catheter encrustation is a high fluid intake. [ABSTRACT FROM AUTHOR]

Objective To test the resistance of currently available types of indwelling urethral catheters to blockage by encrustation with mineralized Proteus mirabilis biofilms. Materials and methods Encrustation was studied in a simple laboratory model of the catheterized bladder. Artificial urine was supplied to the bladder chamber at 0.5 mL/min. The bladder urine was inoculated with a clinical strain of P. mirabilis that had been isolated from an encrusted catheter. The models were operated until the catheters blocked and atomic absorption spectrometry was used to assess the amounts of calcium and magnesium deposited on the catheters. Scanning electron microscopy was also used to locate and assess the degree of encrustation. Results The mean times to blockage ranged from 21 h for the Bard hydrogel/silver-coated latex catheter to 56 h for the Eschmann Folatex S all-silicone catheter. The calcium and magnesium salts were mainly deposited on the 10 cm below the eye-holes of the catheters, complete blockage generally occurring in the 2 cm immediately below the eye-hole. Conclusion None of the 18 types of catheter tested, including those coated with hydrogel or silver, were capable of resisting encrustation by P. mirabilis biofilm. [ABSTRACT FROM AUTHOR]

Objective To investigate the ability of a silver-releasing device to protect the catheterized bladder from infection by blocking the ascending migration of bacteria from contaminated urine-drainage bags. Materials and methods A simple physical model of the catheterized bladder and drainage system was used with the device located in the drainage-tube just below the sampling port. Urine was supplied to the model at 1.0 mL/min and the drainage bag was contaminated with Pseudomonas aeruginosa, Escherichia coli and Proteus mirabilis. Over 10 days, urine from the bag, catheter sampling-port and bladder were examined for contamination. Results Bacteriological analysis showed that the mean time for test organisms to reach the sampling ports of four different control bag systems ranged from 5.7 to 7.7 days. Urine from the sampling ports of the test systems incorporating the silver device remained sterile for 10 days. The device also prevented the growth of the large populations of bacteria (108 colony-forming units per mL) that occurred in the control bags. While scanning electron microscopy showed the formation of bacterial biofilm throughout the control drainage systems, no bacterial colonization was visible on the surfaces of the test systems. Chemical analysis established that the devices consistently generated concentrations of silver in urine ranging from 1.0 to 2.0 μg/mL. Conclusion The incorporation of the silver-releasing device into the drainage systems produced an antibacterial barrier which protected the catheterized bladder from intraluminal contamination for at least 10 days. These in vitro tests suggest a useful role for the device in controlling infection in patients undergoing short-term indwelling bladder catheterization. [ABSTRACT FROM AUTHOR]

Structural polymers with a high modulus of elasticity have the necessary properties for drug eluting implants which are continuously subjected to long‐term loading. The range of polymers that can be used for this purpose is severely limited by the demanding requirements, such as biocompatibility, specific mechanical properties and the capability to control the release rate of incorporated drugs. A new series of blend compositions was developed for these applications, based on a combination of a high modulus thermoplastic segmented polyurethane (TSPU) (shore D hardness) and poly(L‐lactide) (PLLA). The microstructures and properties of these blends were characterized by DSC, tensile tester, FTIR, SEM, WAXD, transmitted light microscopy and elastic recovery testing. The two polymers were found to be immiscible, irrespective of the weight ratio between them, but still compatible, although the compatibility was reduced in blends with equal weight ratios or thereabouts. The dispersed phase in any case spontaneously organized into microspheres embedded within the continuous phase. PLLA could recrystallize as both the dispersed and the continuous phases. The ultimate mechanical properties and the elastic load‐recovery of the blends were largely dependent on the ratio between the polymers. The ability of these blends to create self‐assembled microspheres and the fact that they did not require a compatibilizer or plasticizer point to the potential of these systems to be used for structural implantable drug delivery systems. [ABSTRACT FROM AUTHOR]

A number of pantoprazole derivatives were synthesized and screened for their urease inhibitory properties. Some of them showed potent inhibitions against jack bean urease. All compounds showed varying degree of IC50 in the range of 25.85 to 181 μMol as compared to standard acetohydroxamic acid (AHA) (100±2.02 μMol). Derivatives bearing 5‐aryl‐1,3,4‐oxadiazole ring substitutions (aryl= pyrazyl, pyridyl and phenyl) were found to be more potent inhibitors than AHA and pantoprazole. The most promising compound, 2‐((3,4‐dimethoxypyridin‐2‐yl)methylthio)‐5‐(pyrazin‐2‐yl)‐1,3,4‐oxadiazole 12, with IC50 value of 25.85±1.21 showed remarkable urease inhibition activity. In silico molecular modeling investigation performed to rationalize the possible binding interaction and ADME properties of compounds over the active site of urease enzyme. The induced fit docking study showed that compound 12 interacted with conserved residues His593 and Arg609 located at the mouth of the urease active site flap and are essential for enzyme catalytic activity. These target compounds could be further studied as a lead skeleton for discovery of novel urease inhibitors. [ABSTRACT FROM AUTHOR]

The crystallization of magnesium ammonium phosphate hexahydrate (struvite) often occurs under conditions of fluid flow, yet the dynamics of struvite growth under these relevant environments has not been previously reported. In this study, we use a microfluidic device to evaluate the anisotropic growth of struvite crystals at variable flow rates and solution supersaturation. We show that bulk crystallization under quiescent conditions yields irreproducible data owing to the propensity of struvite to adopt defects in its crystal lattice, as well as fluctuations in pH that markedly impact crystal growth rates. Studies in microfluidic channels allow for time‐resolved analysis of seeded growth along all three principle crystallographic directions and under highly controlled environments. After having first identified flow rates that differentiate diffusion and reaction limited growth regimes, we operated solely in the latter regime to extract the kinetic rates of struvite growth along the [100], [010], and [001] directions. In situ atomic force microscopy was used to obtain molecular level details of surface growth mechanisms. Our findings reveal a classical pathway of crystallization by monomer addition with the expected transition from growth by screw dislocations at low supersaturation to that of two‐dimensional layer generation and spreading at high supersaturation. Collectively, these studies present a platform for assessing struvite crystallization under flow conditions and demonstrate how this approach is superior to measurements under quiescent conditions. [ABSTRACT FROM AUTHOR]

Further to conventional linear, branched, crosslinked, and dendritic polymers, single chain cyclized/knotted polymers (SCKPs) have emerged as a new class of polymer structure with unique properties. Herein, the development of bacteria‐resistant SCKPs is reported and the effect of this structure on the resistance of polymer materials to bacteria is investigated. Four SCKPs were synthesized by reversible addition fragmentation chain transfer (RAFT) homopolymerization of multivinyl monomers (MVMs) and then crosslinked by UV light to form SCKP films. Regardless of MVM type used, the resulting SCKP films showed much higher resistance to bacteria, and up to 75 % less bacterial attachment and biofilm formation, in comparison with the corresponding non‐SCKP films. This is due to the altered surface morphology and hydrophobicity of the SCKP films. These results highlight the critical role of the SCKP structure in enhancing the resistance of polymeric materials to bacteria. [ABSTRACT FROM AUTHOR]

Accurate and sensitive detection of bacteria is crucial in medicine for diagnosis and effective treatment of infectious diseases. Current state-of-the art methods consist of either traditional time consuming microbiological analysis or rapid, sensitive molecular techniques that require expensive readout equipment. In previous work, the authors of this paper combined synthetic bacteria receptors, so-called surface imprinted polymers (SIPs), with a novel thermal biosensor readout methodology for the detection of bacteria in urine. In this follow-up study, the potential of the method for application in urinary tract infection (UTI) diagnosis is further studied. The reproducibility of the method is assessed by expanding the study and analyzing the sensor's performance in urine samples obtained from four healthy adults. The samples are spiked with increasing concentrations of Escherichia coli to obtain different dose-response curves. The results of this study show that the method is reproducible over the studied population and variables such as age, gender and osmolality do not seem to influence the test. All results fall within the previously established dynamic range of 104-105 bacteriamL-1 which fits well within the diagnostic window of classical microbiological UTI tests. Further tests conducted on a urine sample 24 h after spiking illustrate the problem with traditional microbiology tests as the sensor response has significantly decreased due to the presence of a significant amount of dead bacteria in the day-old sample. These results confirm that fast, point-of-care analysis of fresh urine samples is advantageous over classic laborious techniques in terms of accurate diagnosis. [ABSTRACT FROM AUTHOR]

Abstract: Microbial burden associated with medical devices poses serious health challenges and is accountable for an increased number of deaths leading to enormous medical costs. Catheter‐associated urinary tract infections are the most common hospital‐acquired infections with enhanced patient morbidity. Quite often, catheter‐associated bacteriuria produces apparent adverse outcomes such as urosepsis and even death. Taking this into account, the methods to modify urinary catheters to control microbial infections with relevance to clinical drug resistance are systematically evaluated in this review. Technologies to restrict biofilm formation at initial stages by using functional nanomaterials are elucidated. The conventional methodology of using single therapeutic intervention for developing an antimicrobial catheter lacks clinically meaningful benefit. Therefore, catheter modification using naturally derived antimicrobials such as essential oils, curcumin, enzymes, and antimicrobial peptides in combination with synthetic antibiotics/nanoantibiotics is likely to exert sufficient inhibitory effect on uropathogens and is extensively discussed. Futuristic efforts in this area are projected here that demand clinical studies to address areas of uncertainty to avoid development of bacterial resistance to the new generation therapy with minimum discomfort to the patients. [ABSTRACT FROM AUTHOR]

The table of contents for the August 2014 issue of the "Journal of Internal Medicine" is presented.

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. [ABSTRACT FROM AUTHOR]

In peritoneal dialysis (PD), the catheter, usually made of silicone, has been considered the 'lifeline' of the patient. However, the PD catheter also serves as a nidus for bacterial infection. Furthermore, complications can result from fibrin deposition and omental wrapping of the catheter, which obstructs the dialysate flow. In this work, a crosslinked agarose (AG) polymer layer is covalently grafted as a microscale coating on the silicone surface. This coating reduces Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa biofilm formation by more than two orders of magnitude. In addition, cell and platelet adhesion and protein adsorption is also reduced by ≥90%. Without compromising the antibacterial and antifouling property, further improvement in hemocompatibility, as shown by the inhibition of platelet adhesion and activation, prolonged plasma recalcification time and lower hemolysis degree, is achieved by co-immobilization of 2.6 μg cm−2 of heparin (HEP) in the agarose coating. The AG-HEP coatings are not cytotoxic to mammalian cells, and are stable for extended periods in lysozyme aqueous solution and under autoclaving at 121 °C for 20 min. [ABSTRACT FROM AUTHOR]

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The introduction of effective antibacterial therapies for infectious diseases in the mid-20th century completely revolutionized clinical practices and helped to facilitate the development of modern medicine. Many potentially life-threatening conditions became easily curable, greatly reducing the incidence of death or disability resulting from bacterial infections. This overwhelming historical success makes it very difficult to imagine life without effective antibacterials; however, the inexorable rise of antibiotic resistance has made this a very real and disturbing possibility for some infections. The ruthless selection for resistant bacteria, coupled with insufficient investment in antibacterial research, has led to a steady decline in the efficacy of existing therapies and a paucity of novel structural classes with which to replace them, or complement their use. This situation has resulted in a very pressing need for the discovery of novel antibiotics and treatment strategies, the development of which is likely to be a key challenge to 21st century medicinal chemistry. [ABSTRACT FROM AUTHOR]

n-Heptyl α- D-mannoside (HM) has previously been identified as a nanomolar FimH antagonist able to prevent Escherichia coli adhesion. We have designed mono- and heptavalent glycoconjugates in which HM is tethered to β-cyclodextrin (β-CD) through short and long spacers. One-pot click or co-clicking procedures were developed to directly obtain the glycoconjugates from unprotected HM and β-CD precursors. These FimH antagonists were examined biophysically and in vivo. Reverse titrations by isothermal calorimetry led to trapping of the short-tethered heptavalent β-CD in a complex with three FimH lectins. Combined dynamic light scattering and small-angle X-ray solution scattering data allowed the construction of a model of the FimH trimer. The heptavalent β-CDs were shown to capture and aggregate living bacteria in solution and are therefore also able to aggregate FimH when attached to different bacteria pili. The first in vivo evaluation of multivalent FimH inhibitors has been performed. The heptavalent β-CDs proved to be much more effective anti-adhesive agents than monovalent references with doses of around 2 μg instilled in the mouse bladder leading to a significantly decreased E. coli load. Intravenously injected radiolabeled glycoconjugates can rapidly reach the mouse bladder and >2 μg concentrations can easily be retained over 24 h to prevent fluxing bacteria from rebinding. [ABSTRACT FROM AUTHOR]

Nanoscale surface roughness is an important factor in determining the properties of surfaces and can affect the performance of a range of devices prepared by lithographic methods. Here, a method is reported, which enables modulation of the nanoscale roughness of surfaces through the directed self assembly (DSA) of positively charged polymersomes, composed of specifically designed block copolymers, onto negatively charged surfaces. Assembly of the polymersomes on surfaces can result in an increase in the nanoscale surface roughness; however, through a controlled annealing step we can also significantly reduce the nanoscale roughness of the original surface. The ability to decrease the roughness of lithographic patterns is expected to have a significant impact on the manufacture of integrated circuits. [ABSTRACT FROM AUTHOR]

Congenital anomalies such as meningomyelocele and diseases/damage of the central, peripheral, or autonomic nervous systems may produce neurogenic bladder dysfunction, which untreated can result in progressive renal damage, adverse physical effects including decubiti and urinary tract infections, and psychological and social sequelae related to urinary incontinence. A comprehensive bladder-retraining program that incorporates appropriate education, training, medication, and surgical interventions can mitigate the adverse consequences of neurogenic bladder dysfunction and improve both quantity and quality of life. The goals of bladder retraining for neurogenic bladder dysfunction are prevention of urinary incontinence, urinary tract infections, detrusor overdistension, and progressive upper urinary tract damage due to chronic, excessive detrusor pressures. Understanding the physiology and pathophysiology of micturition is essential to select appropriate pharmacologic and surgical interventions to achieve these goals. Future perspectives on potential pharmacological, surgical, and regenerative medicine options for treating neurogenic bladder dysfunction are also presented. [ABSTRACT FROM AUTHOR]

This paper summarizes some applications of ultrasonic vibrations regarding heat transfer enhancement techniques. Research literature is reviewed, with special attention to examples for which ultrasonic technology was used alongside a conventional heat transfer process in order to enhance it. In several industrial applications, the use of ultrasound is often a way to increase productivity in the process itself, but also to take advantage of various subsequent phenomena. The relevant example brought forward here concerns heat exchangers, where it was found that ultrasound not only increases heat transfer rates, but might also be a solution to fouling reduction. [ABSTRACT FROM AUTHOR]

Antibacterial efficacy of silver nanoparticles (Ag NPs) deposited alternatively layer by layer (LBL) on chitosan polymer in the form of a thin film over a quartz plate and stainless steel strip has been studied. An eight-bilayer chitosan/silver (Cs/Ag)8 hybrid was prepared having a known concentration of silver. Techniques such as UV-visible spectroscopy, inductively coupled plasma optical emission spectroscopy (ICP-OES), and atomic force microscopy (AFM) were carried out to understand and elucidate the physical nature of the film. Gram-negative bacteria, Escherichia coli (E. coli), were used as a test sample in saline solution for antibacterial studies. The growth inhibition at different intervals of contact time and, more importantly, the antibacterial properties of the hybrid film on repeated cycling in saline solution have been demonstrated. AFM studies are carried out for the first time on the microbe to know the morphological changes affected by the hybrid film. The hybrid films on aging (3 months) are found to be as bioactive as before. Cytotoxicity experiments indicated good biocompatibility. The hybrid can be a promising bioactive material for the prevention of biofilms specific to E. coli and in purification of water for safe drinking. [ABSTRACT FROM AUTHOR]

OBJECTIVES To test the ability of a sensor developed to signal infection by the organisms that generate the crystalline biofilms that encrust catheters, to give an early warning that encrustation was occurring on patients’ catheters, as the care of many patients undergoing long-term bladder catheterization is complicated by the encrustation and blockage of their catheters PATIENTS AND METHODS Twenty patients were followed prospectively for the lifetime of one of their catheters. Sensors based on cellulose acetate/bromothymol blue were placed in the urine-collection bags, which were changed as usual at weekly intervals. The bacteriology was assessed and pH determined weekly on urine samples. Photographic records were made of the sensors twice weekly. On removal, each catheter was examined for encrustation and blockage. RESULTS Proteus mirabilis was not isolated from five patients and in these cases the sensor colour remained golden-yellow to brown. The catheters drained for the scheduled period and showed no signs of encrustation. By contrast, the sensors turned dark blue/black in the urine of all 15 patients infected with P. mirabilis. All these patients’ catheters were encrusted and in 12 the catheters blocked. The mean interval between the sensor signalling and the catheter blocking was 12 days. CONCLUSION The cellulose acetate/bromothymol blue sensors placed in the urine collection bags are capable of signalling infection by P. mirabilis. They also signal the early stages of catheter encrustation and allow catheter replacement in ample time to avoid the clinical crises and emergency referrals caused by catheter blockage. [ABSTRACT FROM AUTHOR]

- A simple physical model of the catheterised bladder has been used to assess the activities of antiseptic agents that have been recommended as bladder instillations in the treatment of urinary tract infections in patients with indwelling catheters. The activities of povidone-iodine, phenoxyethanol, chlorhexidine, chlorhexidine supplemented with EDTA+Tris, noxythiolin and neomycin were examined against selected species of uropathogens. Except for phenoxyethanol against Pv. stuartii and possibly Ps. aeruginosa, single applications of these antibacterials for 30 min were not effective in sterlising urine in the artificial bladder. However, a second application 1 h later of phenoxyethanol but not chlorhexidine or povidone-iodine did eradicate Ps. aeruginosa. It is suggested that bacteria growing as a film on the bladder wall are particularly resistant to antimicrobials. [ABSTRACT FROM AUTHOR]