[Principles of hygiene in ENT endoscopy]. / Grundsätze der Hygiene bei der HNO-Endoskopie.

This article gives a report on principles of reprocessing of rigid and flexible endoscopes used in ENT units including structural and spatial requirements based on the general and also ENT-specific risks of infection associated with diagnostic and therapeutic endoscopy. The underlying legal principles as well as recommendations from scientific societies will be exemplified in order to give the otorhinolaryngologist a practical guidance.Preliminary results of a nation-wide survey on infection control standards based on data of 29 ENT practices in Germany reveal actual deficits of varying degree concerning infection control management including reprocessing of endoscopes. The presented review aims to give support to the establishment of a structured infection control management program including the evaluation of results by means of a prospective surveillance.

Surgery for acquired cardiovascular disease: antiseptic treatment of contaminated vein grafts.

AIM: Saphenous vein grafts harvested for use as bypass conduits can be contaminated intraoperatively, e.g. by being inadvertently dropped to the floor of the operating room (OR). This study was performed to investigate microorganisms most likely contaminating vein grafts and to assess the possible efficacy of measures to treat potentially contaminated vein grafts antiseptically for further use. METHODS: In a first step we determined the microbiological flora of the OR using surface cultures and cultures from intentionally dropped vein grafts. Several antiseptic agents (PVP-iodine 10%, octenidinhydrochloride 0.1%, polyhexanide 1%) were evaluated for their in vitro efficacy to disinfect artificially contaminated vein segments. The most promising antiseptic regimen was tested on veins contaminated in a real OR setting. Finally, we tested for possible alterations in mechanical properties of the veins caused by antiseptic treatment. RESULTS: Coagulase-negative staphylococci where the predominant bacteria recovered from the OR with 59.9%. Antiseptic treatment with a combination of octenidine and PVP-iodine resulted in a higher rate of negative cultures than any single agent. Treatment of 50 saphenous vein grafts contaminated in the OR with the combination regimen resulted in only 3 positive cultural results within 7 days. Mechanical tear-stress testing comparing antiseptically treated vein grafts with controls showed no difference in their resistance to tear stress. CONCLUSION: Antiseptic treatment of contaminated vein grafts was shown to be effective in a high percentage of cases without altering mechanical properties of grafts and may be an option for the surgeon in case of a contamination.

[Importance of material logistics in the interface management of operation departments: is the supply of sterile equipment a new business area of operation room organization?]. / Bedeutung der Materiallogistik im Schnittstellenmanagement der Operationsabteilungen: Ist die Sterilgutversorgung ein neues Geschäftsfeld der OP-Organisation?

The implementation of diagnosis-related groups (DRGs) sharply increased economic pressure on hospitals. Hence, process optimization was focussed on cost-intensive areas, namely the operation room (OR) departments. Work-flow in the OR is characterized by a mandatory interlocking of the job functions of many different occupational groups and the availability of a variety of different materials. Alternatives for staff assignment optimization have been published in numerous publications dealing with the importance of OR management. In this connection the issue of material logistics in the context of OR management has not been frequently addressed. In order to perform a surgical procedure according to plan, one depends on personnel and on timely availability of the materials needed. Supply of sterilized materials is of utmost importance, because in most hospitals sterilized surgical devices constitute a critical resource. In order to coordinate the OR process with the production flow of sterilized materials, an organizational connection to the OR management makes sense. Hence, in a German university hospital the Department of Hospital Sterile Supplies was integrated into the OR management of the Department of Anesthesiology. This led to a close coordination of work-flow processes, and concomitantly a significant reduction of production costs of sterile supplies could be achieved by direct interaction with the OR. Thus, hospital sterile supplies can reasonably be integrated into an OR management representing a new interesting business area for OR organization.

A new model of skull base reconstruction following expanded endonasal or transoral approaches--long-term results in primates.

OBJECTIVE: The direct endonasal or transoral transclival approaches to the skull base permit effective minimally invasive surgery along the clivus region. Developing consistently effective techniques to prevent cerebrospinal fluid (CSF) leaks and their consequences (infections and healing processes with long and complicated recoveries) remains a major challenge. In this study, we tested over a long period a method of bone reconstruction newly developed by us, which makes use of a specially designed elastic silicone plug that can be employed for bone replacement after minimally invasive skull base surgery without risk of postoperative CSF leaks. After acute testing of plug efficiency in a pig model, which showed a 100% closure of the bone defect without CSF leak, we now tested the long-term accuracy of the plugs. METHODS: In 3 primates, we used an endoscope-controlled transoral transclival approach and after opening the dura we simulated a CSF leakage. We inserted the plug into the bone defect and closed the mucosa of the oral cavity with stitches. The follow-up included blood, weight, and wound control 1, 4 and 8 weeks postoperatively. Social behavior, such as reintegration and postoperative eating abnormalities, was also studied. The aims of this study were: (1) testing the biocompatibility of the material; (2) development of infection against the foreign body; (3) effects of the plug on the surrounding bone, and (4) development of CSF leakages during the postoperative phase. RESULTS: Clinically no infection was seen. Wound healing, immediate and long-term postoperative social behavior of the animals, feeding and body weight were normal. No CSF leakages developed. The histological examination of the clivus bone showed no abnormalities. The implant was covered by fibrous layer; there was no bone atrophy but osteoid formation. CONCLUSION: This novel medical device allows easy, fast and uncomplicated, leak-proof closure of bone defects after minimally invasive craniotomies as seen in transsphenoidal or transoral skull base approaches.

Molecular monitoring of inactivation efficiencies of bacteria during pulsed electric field treatment of clinical wastewater.

AIMS: The applicability of an alternative wastewater disinfection concept based on the pulsed electric field (PEF) treatment is tested with molecular biology techniques using clinical wastewaters. METHODS AND RESULTS: Hospital wastewater was treated with the PEF technology. The inactivation efficiencies of bacteria were successfully monitored with real-time polymerase chain reaction (PCR). As the differentiation between living and dead bacterial cells is important for the determination of the disinfection efficiency, propidium monoazide (PMA) was applied. PMA selectively penetrates cells with compromised membranes and intercalates into the DNA inhibiting a subsequent PCR amplification. The rates of reduction were examined for specific pathogens and wastewater populations using PCR-denaturing gradient gel electrophoresis. The results showed that the main part of the bacterial population could be inactivated efficiently with the PEF treatment. Moreover, it was demonstrated that naturally occurring nuclease activities were not affected by the PEF treatment in contrast to a thermal treatment. CONCLUSIONS: The results indicated that the PEF treatment is an appropriate alternative disinfection concept for the treatment of clinical wastewaters and surpass the disadvantages of other disinfection methods. SIGNIFICANCE AND IMPACT OF THE STUDY: With the use of propidium monoazide for live-dead distinction, a new concept could be developed for the evaluation of disinfection methods.

Modern strategies in the prevention of implant-associated infections.

The application of medical devices either for temporary or permanent use has become an indispensible part of almost all fields of medicine. However, foreign bodies are associated with a substantial risk of bacterial and fungal infections. Implant-associated infections significantly contribute to the still increasing problem of nosocomial infections. To reduce the incidence of such infections, specific guidelines providing evidence-based recommendations and comprising both technological and nontechnological strategies for prevention have been established. Strict adherence to hygienic rules during insertion or implantation of the device are aspects of particular importance. Besides such basic and indispensable aspects, the development of new materials which could withstand microbial adherence and colonization has become a major topic in recent years. Modification of surface by primarily physico-chemical methods may lead to a change in specific and unspecific interactions with microorganisms and, thus, to a reduction in microbial adherence. Medical devices made out of a material that would be ideally antiadhesive or at least colonization-resistant would be the most suitable candidates to avoid colonization and subsequent infection. However, it appears impossible to create a surface with an absolute 'zero'-adherence due to thermodynamical reasons and due to the fact that a modified material surface is in vivo rapidly covered by plasma and connective tissue proteins. Therefore, another concept for the prevention of implant-associated infections involves the impregnation of devices with various antimicrobial substances such as antibiotics, antiseptics, and/or metals. In fact, already commercially available materials for clinical use such as antimicrobial catheters have been introduced, in part with considerable impact on subsequent infections. However, future studies are warranted to translate the knowledge on the pathogenesis of device-associated infections into applicable prevention strategies.

Rifampin-impregnated silicone catheters: a potential tool for prevention and treatment of CSF shunt infections.

BACKGROUND: Infection continues to be one of the major complications of cerebro-spinal fluid shunting procedures. Recent insights in the pathophysiological mechanism of these foreign body infections have elucidated the difficulty of achieving successful treatment without device removal. The development of a rifampin-impregnated silicone catheter yielded excellent results in infection prevention and treatment in vitro as well as in an animal model. PATIENTS AND METHODS: Here, we describe the application of this device in two patients with a complicated course of shunt infection. RESULTS: In one patient the rifampin-impregnated shunt system was implanted after external drainage to prevent further infection. The shunt infection of the second patient was treated by replacement of the infected shunt system with a rifampin-impregnated device. Both patients recovered immediately without any signs of adverse effects and the two shunt systems have now been working properly for more than 36 and 21 months, respectively. CONCLUSION: These results suggest that rifampin-impregnated silicone catheters could become a valuable tool in the treatment and prevention of shunt infections.

Efficacy of NaOCl/H2O2 irrigation and GaAlAs laser in decontamination of root canals in vitro.

BACKGROUND AND OBJECTIVES: To investigate the bactericidal effect of an 809 nm semiconductor laser alone, and in combination with NaOCl/H(2)O(2) irrigation in root canals in vitro. STUDY DESIGN/MATERIALS AND METHODS: A total of 72 human single-rooted teeth extracted for periodontal reasons were included. The crowns were removed, the roots shortened to a length of 12 mm, and the canals enlarged up to an apical size of #50 file. The specimens were autoclaved and incubated with a suspension of Streptococcus sanguinis (ATCC 10556). Laser irradiation was performed on a PC-controlled XY translation stage. A 200 micron optic fiber was used. Twelve specimens were irradiated at a power output of 1.5, 3.0, and 4.5 W in the cw-mode. The total irradiation time was 60 seconds per canal. Twelve specimens were rinsed with NaOCl and H(2)O(2) only, 12 were rinsed and laser treated, and 12 served as untreated controls. After laser treatment, the specimens were sonicated and the bacterial growth was examined by counting colony forming units on blood agar plates. Temperature changes at the outer root surface during irradiation were registered by means of thermocouples. Treated and control specimens were investigated by means of scanning electron microscopy. RESULTS: Mean bacterial reductions of 0.35 log steps at a power output of 1.5 W, 1.44 at 3.0 W, and 2.84 at 4.5 W were calculated. Bacterial reduction by the NaOCl/H(2)O(2) solution alone was 1.48 and comparable to that achieved by irradiation at 3.0 W. With a log kill 2.85, the combination of rinsing and laser irradiation at 3.0 W resulted in a further significant bacterial reduction as compared to rinsing alone (P = 0.004). Irradiation did not result in excessive heat generation at the root surface. Carbonization of the root canal wall was observed in single teeth at 3.0 and 4.5 W and no controlled sealing of the dentinal tubules could be achieved in the root canal. CONCLUSIONS: The application of the diode laser might be an adjunct to conventional endodontic treatment when used in combination with a NaOCl/H(2)O(2) solution.

[Control of low Legionella concentrations in pool water]. / Erfassung niedriger Legionellen-Konzentrationen in Badebeckenwasser.

The Legionella proof is necessary in pool water according to DIN 19 643 in case of possible aerosol formation. In lab tests it was proven that the direct spatulation of 1 ml water offers high-grade proof with high correlation of the determined concentration to the actual germ content. With very small germ concentrations, however, preceding filtration of larger sample volumes is necessary. During the investigation of routine samples a Legionella proof was possible thereby in individual cases, whereas direct spatulation remained negative.

A silicone ventricular catheter coated with a combination of rifampin and trimethoprim for the prevention of catheter-related infections.

So-called antiinfective catheters which are generated by incorporation of antimicrobial substances into polymers appear to be effectful devices in the prevention of catheter related infections. Such devices mainly act by prevention of bacterial colonization of the catheter surface rather than by inhibition of adherence. In a preceding study, we developed a rifampin-containing silicone catheter for the prevention of ventricular shunt infection. In the present study, this work was continued with a combination of antimicrobials incorporated in silicone ventricular catheters to reduce the risk of rifampin resistance and to expand the antimicrobial spectrum. We found that the drug release kinetics could be greatly influenced by the incorporation conditions. It was possible to incorporate an optimal antibiotic combination of rifampin and trimethoprim into the polymer resulting in defined release rates and a defined total release. A catheter loaded with this combination showed an excellent reduction of the colonization with Staphylococcus aureus (99.97% reduction within 3 hours) under in-vitro conditions.

In vitro efficacy of a hydrophilic central venous catheter loaded with silver to prevent microbial colonization.

A method was developed to load the surface of a central venous catheter with silver to prevent bacterial colonization. Silver confers a broad antimicrobial activity with a relatively low risk of resistance. Catheters were incubated with a silver nitrate solution in different concentrations. The solvent, incubation temperature and incubation period were varied to examine the influence on the catheter loading. With increasing incubation temperature, time and concentration of silver nitrate, higher rates of silver elution were observed by atomic absorption spectroscopy. Furthermore, by using ethanol-water as a solvent instead of pure water, the amount of silver bound to the catheter surface was enhanced. The release of silver from the catheter surface is mainly controlled by first order kinetics. Antimicrobial efficacy of the modified catheter, in comparison to unloaded catheters, was tested in a stationary and a dynamic model with different microorganisms. Adherence experiments with Candida albicans showed almost complete inhibition of growth during a period of 72 hours, including initial adherence. While initial adherence of bacteria could not be prevented, these experiments showed an excellent reduction of bacterial colonization. In a perfusion model, adhesion of E. coli could be reduced for at least seven days. Further studies are planned to examine prolonged antimicrobial effects.

Polymer materials for the prevention of catheter-related infections.

Catheter-related infections are major problems in medicine because of severe consequences for the patient, prolongation of hospitalization, and increasing therapy costs. Beside progress in hygienic measures, development of catheters with antiinfective properties seems to be a promising approach to the prevention of such infections. Two approaches for infection-resistant catheter materials have been developed: materials with antiadhesive properties and materials with antimicrobial properties. Antiadhesive polymers shall prevent the adhesion of microorganisms to the medical device. However, up to now there has been no material which would lead to a complete inhibition of adherence ("zero adherence"). Materials with antimicrobial properties contain antimicrobial substances which are incorporated into the biomaterial or bound to the polymer surface. These devices seem to be effective in the prevention of "early onset infections". In this paper, an overview of the development and efficiency of antiadhesive or antimicrobial polymers is given.

Prevention of biofilm formation by polymer modification.

Bacterial biofilm formation on synthetic polymers plays an important role in industry and in modern medicine, leading, for example, to difficult-to-treat infections caused by colonized foreign bodies. Prevention of biofilm formation is a necessary step in the successful prophylaxis of such infections. One approach is to inhibit bacterial adherence by polymer surface modification. We have investigated polymer modification by glow discharge treatment in order to study the influence of the modified surface on bacterial adherence. Surface roughness, surface charge density and contact angles of the modified polymers were determined and related to the adherence of Staphylococcus epidermidis KH6. Although no influence of surface roughness and charge density on bacterial adherence was noticed, a correlation between the free enthalpy of adhesion (estimated from contact angle measurements) and adherence was observed. There seems to exist a certain minimum bacterial adherence, independent of the nature of the polymer surface. Modified polymers with negative surface charge allow for bacterial adherence close to the adherence minimum. These polymers could be improved further by the ionic bonding of silver ions to the surface. Such antimicrobial polymers are able to prevent bacterial colonization, which is a prerequisite for biofilm formation. It is suggested that modification of polymers and subsequent surface coupling of antimicrobials might be an effective approach for the prevention of bacterial biofilm formation.