Albumin reduces the antibacterial efficacy of wound antiseptics against Staphylococcus aureus.

OBJECTIVE: The influence of proteins on the efficacy of antiseptic solutions has been rarely investigated even though exudate can contain high levels of protien. The aim of this study was to analyse the antibacterial efficacy of commonly used solutions in the presence of albumin protein. METHOD: Using Staphylococcus aureus in a standardised quantitative suspension assay, the antibacterial effects of poly (1-(2-oxo-1-pyrrolidinyl) ethylene)-iodine (PVP-I) and octenidin-dihydrochloride/phenoxyethanol (OCT/PE) were analysed in the presence of 0-3% bovine serum albumin (BSA). These were compared with previous results obtained with polyhexamethylene biguanide hydrochloride (PHMB). RESULTS: Presence of albumin caused a significant (p<0.001) decrease in antibacterial effect in the analysed solutions. The concentrations of albumin that provoked highly significant decreases in the bacterial reduction factors of the study agents were: 0.01875 % for PVP-I, followed by 0.75 % for OCT/PE. After addition of 3 % albumin, adequate antimicrobial effects were ensured for titrations to 5 % PVP-I and 8 % OCT/PE. As we could show before, it is not possible to titrate PHMB in order to assure adequate potency. CONCLUSION: This study demonstrates that albumin induces a significant decrease of the antibacterial potency of the analysed solutions.

Surgeons' exposure to sevoflurane during paediatric adenoidectomy: a comparison of three airway devices.

Although sevoflurane is commonly used in anaesthesia, a threshold value for maximum exposure to personnel does not exist and although anaesthetists are aware of the problem, surgeons rarely focus on it. We used a photo-acoustic infrared device to measure the exposure of surgeons to sevoflurane during paediatric adenoidectomies. Sixty children were randomly allocated to laryngeal mask, cuffed tracheal tube or uncuffed tracheal tube. The average mean (maximum) sevoflurane concentrations within the surgeons' operating area were 1.05 (10.05) ppm in the laryngeal mask group, 0.33 (1.44) ppm in the cuffed tracheal tube group and 1.79 (18.02) ppm in the uncuffed tracheal tube group, (p < 0.001), laryngeal mask and cuffed tracheal tube groups vs. uncuffed tube group. The presence of sevoflurane was noticed by surgeons in 20% of cases but there were no differences between the groups (p = 0.193). Surgical and anaesthetic complications were similar in all three groups. We conclude that sevoflurane can be safely used during adenoidectomies with all three airway devices, but in order to minimise sevoflurane peak concentrations, cuffed tracheal tubes are preferred.

Albumin reduces the antibacterial activity of polyhexanide-biguanide-based antiseptics against Staphylococcus aureus and MRSA.

BACKGROUND: Wound infection is one of the major complications in acute and chronic wound healing. Antiseptic solutions and wound irrigating agents are routinely used for therapy and prevention in healthcare today. Even if wound exudate contains total protein concentrations up to 9.3% and albumin concentrations up to 2.7% its influence to the antibacterial efficacy of these agents is barely investigated. MATERIALS AND METHODS: This study analyzed the antibacterial effect of polyhexanide biguanide (PHMB) agents (PHMB-concentration 0.005-0.1%) against Staphylococcus aureus and methicillin-resistant-S. aureus (MRSA) after 2min incubation in presents of albumin in different concentrations (0-3%) in a standardized quantitative suspension assay. RESULTS: A significant decrease of the antibacterial activity against S. aureus was shown for a PHMB-concentration of 0.005% from 0.3% albumin (p<0.05), respectively highly significant from 0.75% (p<0.01) on. Thereby the loss of antimicrobial effect was presented as a linear correlation to the rising concentration of albumin. Furthermore a reduction of the antibacterial activity against MRSA in comparison to S. aureus was presented, for albumin concentrations from 3% on highly significant (p<0.01). CONCLUSION: The study showed that albumin causes a significant decrease of the antibacterial potency of PHMB-based antiseptics. Furthermore a diminished potency of the investigated substances for MRSA-contaminated wounds must be taken in consideration. If in vitro experiments show a significant decrease of antibacterial efficacy in the presence of albumin a sufficient activity of PHMB-based agents in clinical practice, especially in cases of exuding wounds or dried-up exudates, cannot be expected.

[A comparative in vitro study of cell toxicity of clinically used antiseptics]. / Vergleichende In-vitro-Studie zur Zytotoxizität klinisch eingesetzter Antiseptika.

PURPOSE: Local skin antiseptics are the standard of care for chronic and non-healing wounds. However, little is known about their potential toxic properties. This study investigates the impact of three commercially available and widely used antiseptics on vitality and proliferation of human cutaneous cells. MATERIAL AND METHODS: Three antiseptics, Lavasept (PHMB), Octenisept (octenidine) and Betaisodona (PVP-iodine) were tested for their cytotoxic effects towards HaCaT cells, primary human keratinocytes and fibroblasts using MTT assay and BrDU ELISA. RESULTS: Lavasept showed only slight to moderate toxic effects on cellular vitality and proliferation. Ocentisept and Betaisodona induced severe reduction of cell vitality (p<0.05) to 0% surviving fibroblasts at 7.5% (Betaisodona) and 12.5% Octenisept, respectively. Furthermore, poliferative activity was reduced to 0% in keratinocytes at 7.5% concentration of Betaisodona and Ocentisept. CONCLUSION: This study shows that frequently used wound- and skin antiseptics show severe cytotoxic effects towards cutaneous cells. Furthermore, antimicrobial efficacy and toxic properties must be included in the clinical decision process for optimal therapy of chronic wounds. The PHMB solution Lavasept showed best results regarding toxicity in this study.

[The necessity for alternative methods of hygienic testing of air technical designs for operating rooms]. / Zur Notwendigkeit alternativer Methoden der Hygieneabnahme raumlufttechnischer Anlagen für Operationsräume.

The performance assessment of technical systems for the supply of clean air is fraught with problems which are caused by the present assessment procedures and norms. Until now the distribution of germs in a clean room has been considered as stationary and has been tested as though it was independent of the measuring time. Accordingly the quality of clean air rooms has to date been determined by measurements of particle or germ concentrations (Federal Standard 209; European Standard 209-WG-1; VDI 2083/1). By contrast different methods demonstrate that the contaminations introduced into a clean air room as particles or as particle-bound bacteria are eliminated according to an exponential function in a time-dependent manner. Therefore the measurements of single concentrations without the consideration of the time-dependence of concentration changes must needs lead to extremely faulty results. Furthermore the influence of disturbing factors (test persons, properties of different air supply ceilings, measuring instruments). As a consequence of the poor reliability and lacking validity of presently valid assessment methods, there is a discrepancy between the seemingly high performance of the clean air supply systems under laboratory conditions (DIN 4799) on the one hand, and the frequently unsatisfactory functioning of the same systems under practical conditions. This discrepancy has caused a significant loss of confidence towards the whole clean air technique, especially among the users. Therefore critical test and evaluation methods should be immediately set up for comprehensive testing of technical clean air systems, methods which include the time-dependence of particle or germ elimination as well as test-dependent disturbing factors.

[Differentiation of allotments for occupationally necessary and hygiene relevant costs of air technology designs for operating rooms]. / Differenzierung des arbeitsmedizinisch erforderlichen sowie des hygiene-relevanten Kostenanteils raumlufttechnischer Anlagen für Operationsräume.

The aeration of operation theatres serves multiple purposes. It is necessary for the regulation of room temperature (waste heat generated by the operation team and technical appliances), air exchange for oxygen supply, removal of narcotic gases and of smells (occupational limit values) as well the elimination of germs and particles emitted during operations by staff and from instruments (avoidance of germ transfer by air). This paper tries on the one hand to estimate the investment and running costs of different indoor air supplies according to the specifications given by DIN 1946, parts 2 and 4) and on the other hand to differentiate the hygienically relevant expenses of turbulent and laminar flow air supply systems. It can be seen that, due to the high heat production generated during operations, no cost can be saved through decreases in air flow volume. Depending on the operation frequency (e.g. 4 operations daily, 200-300 days per year) a hygienically relevant cost of DM 2.8-6.7 per patient is calculated for laminar flow supplies and DM 4.5-6.7 per patient for the turbulent air supply systems ("Stützstrahl"). Thus laminar flow systems are also cost-saving in comparison to turbulent air supply systems in addition to their significant technical and hygienic advantages.

[Simultaneous measurement of the kinetics of disinfection temperatures using pyoptometer techniques in the capillary system of a new type of inhalation device]. / Koinzidente Messungen der Kinetik von Desinfektions-temperaturen mittels Pyoptometer-Technik im Kapillarsystem eines neuartigen Inhalationsgerätes.

Due to patient collectives with chronic respiratory diseases it is important to avoid the transfer of pathogenic as well as opportunistic nosocomial infective agents during inhalation therapy. According to the literature in clinical practice the colonization with gram negative bacteria constitutes a hygienically relevant hazard. We have tested an inhaler whose patient-side inhalation insert can be autoclaved and whose other parts, whether filled with water or air, can be partially disinfected through a programmable hot air stream. In simultaneous measurements of the disinfecting temperature at four positions of the basic appliance the time-dependent kinetics could be shown for different conditions of thermoisolation and flow of the volume stream by means of pyoptometer thermal probes. The pyoptometer probe technique, which is based on a change of the wave length of laser light in a gallium crystal of 0.5 mm diameter, allows temperature measurements practically without delay. As the connection from the probe crystal to the laser sensor is made by glass fibre cable, the measuring lead remains unaffected by galvanic-technical and secondary thermal effects. It could be demonstrated that the required disinfection temperature in the capillary system of the entire inhaler was reached within 17 min even under worst case conditions (studies of the longest capillary, water replenishment of the entire system before disinfection). Compared to former systems the evaluated apparatus constitutes thus a significant progress in the development of inhalation systems.

[Experimental studies of thermal disinfection and sterilization of allogeneic bone transplants and their effects on biological viability]. / Experimentelle Untersuchungen zur thermischen Desinfektion und Sterilisation allogener Knochentransplantate und deren Auswirkungen auf die biologische Wertigkeit.

Thermal energy (80 degrees) for the disinfection of cancellous allogenic bone grafts was employed, and it proved to be an advantageous, safe and easily accessible method. The effects of this treatment on biological values were examined in terms of biomechanical and biodynamic (graft incorporation) loss of the treated grafts versus the autoclaved and untreated samples. Given the thermolability of the pathogens in question, the thermal approach presented here has the advantage of being readily controllable. The lack of toxic or mutagenic risks through this method and its accessibility represent further advantages. In thermal treatment of bone allografts, it is essential that one knows the thermoconductivity of the bone sample and that one can demonstrate pathogen inactivation through the entire graft volume. All of the parameters in the 80 degrees C group that were measured in this study indicate clear biological superiority over the autoclaved group. A newly developed thermoincubator is introduced for gentler disinfection of allogenic bone grafts and it inactivates common vegetative pathogens as well as HIV. It is still necessary to conduct serological screening for hepatitis antigens in the donor pool, however. Based on these results, we conclude that the clinical use of autoclaved allogenic bone grafts needs to be reviewed and possibly limited.