Development of thermally switchable dosing systems for a LAMP-rapid detection of MRSA
IGF 17775 N
Due to lack of hygiene each year between 0.8 and 1.2 millions of hospital-acquired infections occur in Germany, of which 20,000 to 70,000 are fatal. Methicillin-resistant Staphylococcus aureus (MRSA) now represent a 12.5 % share of one of the most common causes of nosocomial infections. Already the establishment and control of hygiene protection measures lead to an efficient prevention of MRSA infections. Therefore, regular proof of successfully performed disinfection measures by hospital operators and cleaning services is of increasing importance.
Since suitable rapid methods for self-monitoring are not available, cleaning service providers currently use microbiological methods like contact plates or swabs for sampling surfaces. Afterwards the contact plates must be incubated and evaluated by external microbiological laboratories. This method is cost-intensive and requires at least 3 days before results are available.
The aim of the research project was the development of a rapid MRSA detection method for surfaces, which can be easily used by cleaning services as self-control. Because of this, evidence of successfully performed cleaning and disinfection measures are available at latest after 3 hours so that a continuous control and documentation within self-controls will be made possible.
As basis for the development of the rapid test system, LAMP-PCR for the specific genetic determination of MRSA was established. The amplified DNA-amounts can be determined semi-quantitatively due to the developed colour reference scale. To exclude false-positive results, an initial step for the degradation of extracellular DNA from dead microorganisms was developed. In order to subsequently release the needed target DNA from MRSA, optimal lysis and DNA extraction conditions were determined. For the removal of inhibiting effects of the used lysis reagents, an additional DNA-cleaning step based on the use of DNA-binding magnetic beads was developed.
For substitution of the needed pipetting steps for the LAMP-system, hydrogels, which released defined volumes of lysis as well as LAMP reagents at specific temperatures, were developed as thermally switchable dosing systems. The applicability of the thermally switchable dosing systems was analysed with regard to their thermosensitive swelling properties, mechanical stability as well as loading and unloading properties. Based on these results, a functional model of the LAMP-rapid test system for MRSA detection in combination with thermally switchable dosing systems was developed.
Thus, a rapid MRSA detection method was developed that can be used as part of on-site self-monitoring within quality management systems, in order to promptly detect possible failures in the disinfection process and, if necessary, immediately initiate corrective actions.
The IGF-project 17775 N of the research association Europäische Forschungsgemeinschaft Reinigungs- und Hygienetechnologie e.V., Campus Fichtenhain 11, D-47807 Krefeld, was supported via the AiF within the funding programme „Industrielle Gemeinschaftsforschung und –entwicklung (IGF)“ by the Federal Ministry of Economic Affairs and Energy (BMWi) due to a decision of the German Parliament.
The research report is available on request from FRT.