Nils-Olaf Hübner

Cost comparison of MRSA screening and management – a decision tree analysis

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) infections represent a serious challenge for health-care institutions. Rapid and precise identification of MRSA carriers can help to reduce both nosocomial transmissions and unnecessary isolations and associated costs. The practical details of MRSA screenings (who, how, when and where to screen) remain a controversial issue.MethodsAim of this study was to determine which MRSA screening and management strategy causes the lowest expected cost for a hospital. For this cost analysis a decision analytic cost model was developed, primary based on data from peer-reviewed literature. Single and multiplex sensitivity analyses of the parameters “costs per MRSA case per day”, “costs for pre-emptive isolation per day”, “MRSA rate of transmission not in isolation per day” and “MRSA prevalence” were conducted.ResultsThe omission of MRSA screening was identified as the alternative with the highest risk for the hospital. Universal MRSA screening strategies are by far more cost-intensive than targeted screening approaches. Culture confirmation of positive PCR results in combination with pre-emptive isolation generates the lowest costs for a hospital. This strategy minimizes the chance of false-positive results as well as the possibility of MRSA cross transmissions and therefore contains the costs for the hospital. These results were confirmed by multiplex and single sensitivity analyses. Single sensitivity analyses have shown that the parameters “MRSA prevalence” and the “rate of MRSA of transmission per day of non-isolated patients” exert the greatest influence on the choice of the favorite screening strategy.ConclusionsIt was shown that universal MRSA screening strategies are far more cost-intensive than the targeted screening approaches. In addition, it was demonstrated that all targeted screening strategies produce lower costs than not performing a screening at all.

Pilot-study on the influence of carrier gas and plasma application (open resp. delimited) modifications on physical plasma and its antimicrobial effect against Pseudomonas aeruginosa and Staphylococcus aureus.

Introduction: Physical plasma is a promising new technology regarding its antimicrobial effects. This is especially accounting for treatment of bacterial infection of chronic wounds. Plasma can be generated with different carrier gases causing various biological effects. Screening of different carrier gases and plasma generation setups is therefore needed to find suitable compositions for highly effective antimicrobial plasma treatments and other applications. Method: The plasma source used was a radio-frequency plasma jet which generates tissue tolerable plasma (TTP). The study compared the antimicrobial efficacy of air, argon, or helium plasma alone or admixed with 0.1%, 0.5%, and 1% oxygen against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). Treatment took place in an environmentally open and delimited system. Therefore, bacteria were plated on agar and treated with plasma in a punctiform manner. The resulting inhibition zones were measured and the reduction factors were calculated by colony counting, respectively. Results: For S. aureus and P. aeruginosa, inhibition zones and overall reduction of colony forming units (CFU) on the agar plate were observed while an accumulative reduction of CFU dominated for S. aureus. The highest antimicrobial effect was shown in form of an inhibition zone for argon plasma with 0.1% oxygen admixture for both species. S. aureus was more sensitive for helium plasma with >0.1% oxygen admixture compared to P. aeruginosa which in turn was more sensitive for argon plasma with and without oxygen. The efficacy of air plasma was very low in comparison to the other gases. The treatment in a closed system predominantly enhanced the antimicrobial effect. The effect intensity varied for each treatment time and gas mixtures. Discussion: As expected, the antimicrobial effect mostly increased when increasing oxygen admixture to the carrier gases. The variation in bacterial growth and inhibition after exposure to different plasma gas compositions could be due to a varying generation of reactive oxygen species or radiation. Conclusion: The applied plasma in a “closed system” accumulates bactericidal plasma species and might increase antimicrobial efficacy in clinical settings as in wound management involving multi-drug resistant bacteria.

Tissue Tolerable Plasma and Polihexanide: Are Synergistic Effects Possible to Promote Healing of Chronic wounds? In Vivo and In Vitro Results

The assumption is that tissue tolerable plasma works as promoter for wound healing and can be beneficially combined with the antiseptic polihexanide to avoid bacterial recolonization. The effects of a combined plasma – polihexanide (PHMB) application on cell integrity, cytotoxicity and its irritative and inflammative potential were tested in vitro and in two dogs in vivo.

Infection prevention during anaesthesia ventilation by the use of breathing system filters (BSF): Joint recommendation by German Society of Hospital Hygiene (DGKH) and German Society for Anaesthesiology and Intensive Care (DGAI).

An interdisciplinary working group from the German Society of Hospital Hygiene (DGKH) and the German Society for Anaesthesiology and Intensive Care (DGAI) worked out the following recommendations for infection prevention during anaesthesia by using breathing system filters (BSF). The BSF shall be changed after each patient. The filter retention efficiency for airborne particles is recommended to be >99% (II). The retention performance of BSF for liquids is recommended to be at pressures of at least 60 hPa (=60 mbar) or 20 hPa above the selected maximum ventilation pressure in the anaesthetic system. The anaesthesia breathing system may be used for a period of up to 7 days provided that the functional requirements of the system remain unchanged and the manufacturer states this in the instructions for use. The breathing system and the manual ventilation bag are changed immediately after the respective anaesthesia if the following situation has occurred or it is suspected to have occurred: Notifiable infectious disease involving the risk of transmission via the breathing system and the manual bag, e.g. tuberculosis, acute viral hepatitis, measles, influenza virus, infection and/or colonisation with a multi-resistant pathogen or upper or lower respiratory tract infections. In case of visible contamination e.g. by blood or in case of defect, it is required that the BSF and also the anaesthesia breathing system is changed and the breathing gas conducting parts of the anaesthesia ventilator are hygienically reprocessed. Observing of the appropriate hand disinfection is very important. All surfaces of the anaesthesia equipment exposed to hand contact must be disinfected after each case.

The durability of examination gloves used on intensive care units

BackgroundThe use of examination gloves is part of the standard precautions to prevent medical staff from transmission of infectious agents between patients. Gloves also protect the staff from infectious agents originating from patients. Adequate protection, however, depends on intact gloves. The risk of perforation of examination gloves is thought to correlate with duration of wearing, yet, only very few prospective studies have been performed on this issue.MethodsA total number of 1500 consecutively used pairs of examination gloves of two different brands and materials (latex and nitrile) were collected over a period of two months on two ICU’s. Used gloves were examined for micro perforations using the “water-proof-test” according to EN 455–1. Cox-regression for both glove types was used to estimate optimal changing intervals.ResultsOnly 26% of gloves were worn longer than 15 min. The total perforation rate was 10.3% with significant differences and deterioration of integrity of gloves between brands (p<0.001). Apart from the brand, “change of wound dressing” (p = 0.049) and “washing patients” (p = 0.001) were also significantly associated with an increased risk of perforation.ConclusionMedical gloves show marked differences in their durability that cannot be predicted based on the technical data routinely provided by the manufacturer. Based on the increase of micro perforations over time and the wearing behavior, recommendations for maximum wearing time of gloves should be given. Changing of gloves after 15 min could be a good compromise between feasibility and safety. HCWs should be aware of the benefits and limitations of medical gloves. To improve personal hygiene hand disinfection should be further encouraged.

Microbiological safety and cost-effectiveness of weekly breathing circuit changes in combination with heat moisture exchange filters: a prospective longitudinal clinical survey

Aim: To assess the safety and cost effectiveness of a usage for seven days of breathing circuit systems (BCSs) in combination with heat moisture exchanger filters (HMEF) in operation room anesthesia. Method: In a prospective longitudinal clinical study, the contamination on high-risk surfaces (HMEF together with inner and outer surface of BCS) was monitored over 1, 2, 5, and 7 days. Results of endogenous respiratory patient flora and contamination flora of BCS, HMEF and bag were compared. Costs of prolonged use of BCS together with HMEF up to 7 days were calculated. Results: Neither physiological respiratory flora nor colonizing pathogens of the oropharynx of the ventilated patients were transmitted through the filters at any time. None of the included patients developed a postoperative pneumonia. Using the BCS for 24 hours provides a cost savings of up to 40% versus single use. Extending the change interval from 24 hours to 48 hours saved over 50% compared to change after each patient, and an additional 19% compared to change after 24 hours. In combination with a HMEF BCS can be used up to 7 days without clinical risk on multiple patients in operation room settings. Conclusion: Expanding the usage of berating in combination with usage of moist exchange filters is feasible, microbiologically safe and cost effective, as 41% of material costs per ventilation may be saved. Further research is needed to confirm these results.

Übersichtsartikel: Patientensicherheit als nationales Gesundheitsziel: Status und notwendige Handlungsfelder für die Gesundheitsversorgung in Deutschland☆

For some years patient safety has been an important topic for the design of the healthcare systems in many countries. In Germany we are still in the starting phase of this development. Here, patient safety is not a main focus for research and there is only little funding for these topics. Thus most findings on patient safety have been derived in foreign studies. Slowly, some find their way into the clinical routine in Germany. This paper summarises the state of development of patient safety from a trans-sectoral point of view and outlines essential fields of action for the German healthcare system.

Practices of skin care among nurses in medical and surgical intensive care units: results of a self-administered questionnaire.

Dermatitis of hands is a problem among nurses. The aim of this prospective questionnaire based survey was to analyze practice and knowledge of skin care of medical and surgical nurses. 250 questionnaires were distributed. 49% of respondent stated that they perform skin care at least 1–2 times/day. After hand-wash 15% of participants perform skin protection, after hand-disinfection only 2%. 40% give skin care products less than 3 minutes to be applied. It was shown that this knowledge is lacking in many individuals, leading to wrong behavior at work and insufficient use of skin protection and skin care products.

Minimum inhibitory (MIC) and minimum microbicidal concentration (MMC) of polihexanide and triclosan against antibiotic sensitive and resistant Staphylococcus aureus and Escherichia coli strains.

Background: An in-vitro study was conducted investigating the antimicrobial efficacy of polihexanide and triclosan against clinical isolates and reference laboratory strains of Staphylococcus aureus and Escherichia coli. Methods: The minimal inhibitory concentration (MIC) and the minimal microbicidal concentration (MMC) were determined following DIN 58940-81 using a micro-dilution assay and a quantitative suspension test following EN 1040. Polihexanide was tested in polyethylene glycol 4000, triclosan in aqueous solutions. Results: Against all tested strains the MIC of polihexanide ranged between 1–2 µg/mL. For triclosan the MICs varied depending on strains ranging between 0.5 µg/mL for the reference strains and 64 µg/mL for two clinical isolates. A logRF >5 without and logRF >3 with 0.2% albumin burden was achieved at 0.6 µg/mL triclosan. One exception was S. aureus strain H-5-24, where a triclosan concentration of 0.6 µg/mL required 1 minute without and 10 minutes with albumin burden to achieve the same logRFs. Polihexanide achieved a logRF >5 without and logRF >3 with albumin burden at a concentration of 0.6 µg/mL within 30 sec. The exception was the North-German epidemic MRSA strain, were an application time of 5 minutes was required. Conclusion: The clinical isolates of E. coli generally showed higher MICs against triclosan, both in the micro-dilution assay as well in the quantitative suspension test than comparable reference laboratory strains. For polihexanide and triclosan strain dependant susceptibility was shown. However, both antimicrobial compounds are effective when used in concentrations common in practice.

Screening test for quality control of surface barrier discharged plasma sources with the microorganism-agar test (MAT).

In the recent past, the antimicrobial applicability of tissue tolerable plasma (TTP) has been examined, and is increasing in importance. Many different plasma sources can be used medically. In order to obtain reliable test results by using plasma sources, it is essential not only to assess physical parameters but also to screen a use-oriented application of plasma sources. It is necessary to both determine the biological efficacy and establish uniform coverage of the treated surfaces. This article shows a simple screening method for this. We used newly inoculated agar plates with bacterial test organisms and treated the agar plates with two surface barrier discharged (SDB) plasmas. The carrier gas was argon and air.