Meticillin-resistant Staphylococcus aureus Contact Screening Strategy in a Low Prevalence Setting; a Nested Case-Control Study.

Background The optimal screening strategy in hospitals to identify secondary cases after contact with a meticillin-resistant Staphylococcus aureus (MRSA) index patient in a low prevalence setting is not well defined. We aimed at identifying factors associated with documented MRSA transmissions. Method Single center, retrospective, nested case-control study. We evaluated the screening strategy in our 950 bed tertiary care hospital from 2008 - 2014. Room and ward contacts of MRSA index patients present at time of MRSA identification were screened. We compared characteristics of Staphylococcus aureus Protein A (spa)-type matched contact patients (cases) to negative or spa-type mismatched contact patients (controls). Results Among 270,000 inpatients from 2008 - 2014, 215 MRSA screenings yielded 3013 contact patients, and 6 (0.2%) spa-type matched pairs. We included 225 controls for the nested case-control study. The contact type for the cases was more frequently "same room" and less frequently "same ward" compared with the controls (P = 0.001). Also, exposure time was longer for cases (median of 6 days [IQR 3-9]) than for controls (1 day [0-3], P=0.016). Conclusion The extensive MRSA screening strategy revealed only few index/contact matches based on spa-typing. Prolonged exposure time and a shared room were significantly associated with MRSA transmission. A targeted screening strategy may be more useful in a low prevalence setting than screening entire wards

Creating a Flexible Middleware for Low-Power Flooding Protocols

Low-power wireless networks allow for easy-deployment and low-maintenance solutions for sensor applications. Glossy, an often used communication primitive to build such low-power wireless networks, is a flooding protocol providing high reliability and resilience. Even though the list of protocols building on top of Glossy is extensive, the current approach to implement Glossy-based protocols could be significantly improved by separating low-level complexity from high- level protocol logic. The Glossy Middleware presented in this thesis provides system designers with a well-defined, yet versatile interface. Building on top of a round-based framework, the Glossy Middleware offers a vast amount of control over important Glossy parameters on a high-level. This report presents the design and features of the Glossy Middleware in detail, while also serving as an user manual. The evaluation displays the low performance overhead in terms of memory and energy usage as well as the high usability by reimplementing different existing protocols in addition to others, illustrating the various features of the middleware. The middleware has been designed with hardware portability in mind: currently it is fully supported on the DPP platform and to some extent on the TelosB platform. This thesis concludes by illustrating possible improvements on the existing work while also outlining exiting possibilities of the developed Glossy Middle- ware

Synchronous Transmissions Made Easy: Design Your Network Stack with Baloo

Synchronous Transmissions is a technology that combines energy efficiency and reliability for low-power wireless multi-hop networks. But using this technology to design network stacks is a complex task, in part due to the tight timing requirements on the execution of radio operations. To facilitate the development of protocols based on Synchronous Transmissions, we developed Baloo, a flexible network stack design framework, which we present in this paper. We show that Baloo is flexible enough to implement a wide variety of network layer protocols, while introducing only limited memory and energy overhead. Most importantly Baloo makes Synchronous Transmissions accessible: The software is open source and well documented. We believe that Baloo will be an important enabler for a whole new class of Internet of Things applications leveraging the reliability, efficiency, and flexibility of Synchronous Transmissions

Synchronous Transmissions Made Easy: Design Your Network Stack with Baloo

Synchronous Transmissions is a technology that combines energy efficiency and reliability for low-power wireless multi-hop networks. But using this technology to design network stacks is a complex task, in part due to the tight timing requirements on the execution of radio operations. To facilitate the development of protocols based on Synchronous Transmissions, we developed Baloo, a flexible network stack design framework, which we present in this paper. We show that Baloo is flexible enough to implement a wide variety of network layer protocols, while introducing only limited memory and energy overhead. Most importantly Baloo makes Synchronous Transmissions accessible: The software is open source and well documented. We believe that Baloo will be an important enabler for a whole new class of Internet of Things applications leveraging the reliability, efficiency, and flexibility of Synchronous Transmissions

Adding vancomycin to perioperative prophylaxis decreases deep sternal wound infections in high-risk cardiac surgery patients.

OBJECTIVES Perioperative prophylaxis with cephalosporins reduces sternal wound infections (SWIs) after cardiac surgery. However, more than 50% of coagulase-negative staphylococci, an important pathogen, are cephalosporin resistant. The aim of this study was to determine the impact of adjunctive vancomycin on SWIs in high-risk patients. METHODS We conducted a pre- and postintervention study in an academic hospital. Preintervention (2010-2011), all patients received prophylaxis with 1.5 g of cefuroxime for 48 h. During the intervention period (2012-2013), high-risk patients additionally received 1 g of vancomycin. High-risk status was defined as body mass index ≤18 or ≥ 30 kg/m2, reoperation, renal failure, diabetes mellitus, chronic obstructive pulmonary disease or immunosuppressive medication. Time series analysis was performed to study SWI trends and logistic regression to determine the effect of adding vancomycin adjusting for high-risk status. RESULTS A total of 3902 consecutive patients (n = 1915 preintervention and n = 1987 postintervention) were included, of which 1493 (38%) patients were high-risk patients. In the high-risk group, 61 of 711 (8.6%) patients had SWI before and 30 of 782 (3.8%) patients after the intervention. Focusing on deep SWI (DSWI), 33 of 711 (4.6%) patients had DSWI before and 13 of 782 (1.7%) patients afterwards; the absolute risk difference of 2.9% yielded a number-needed-to-treat of 34 to prevent 1 DSWI. Corrected for high-risk status, adding vancomycin significantly reduced the overall SWI rate (odds ratio 0.42, 95% confidence interval 0.26-0.67; P < 0.001) and the subset of DSWI (odds ratio 0.30, 95% confidence interval 0.14-0.62; P = 0.001). The rate of SWI in low-risk patients remained unchanged. CONCLUSIONS Adding vancomycin to standard antibiotic prophylaxis in high-risk patients significantly reduced DSWI after cardiac surgery