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Novel Approach Against Central Venous Catheter
ments were individually sonicated for 5 min and vortexed for 30s Associated Infection With Acinetobacter
in 1 ml NS. Aliquots ͑100 uL͒ of the sonicated fluids and their Baumannii Biofilm
dilutions were inoculated onto Mueller Hinton agar plates. Eachset of experiments was repeated three times. Bacterial colonies W. Elkhatib and A. Noreddin
͑CFU/cm͒ were counted after incubation for 24 h. The average University of Minnesota, Duluth, USA colony count of each set of experiment was calculated. The aver-age values of the treated sets were divided by the average value of Central venous catheter ͑CVC͒-associated infections have sub- the control percent for calculation of the percentage biofilm reduc- stantial impacts on morbidity, mortality, and overall cost of health tion in each treatment as compared to the untreated control ͑NS͒.
care. Acinetobacter baumannii causes severe infections, survives Using ANOVA, the significance level for all analyses was Ͻ0.05.
on abiotic surfaces, colonizes and develops resistant biofilm on The effect of moxifloxacin alone was similar to the untreated con- different medical devices including CVC. The cranberry contains trol. Cranberry extract could reduce the biofilm by almost 90%.
proanthocyanidines which possess antiadherent activity against Moreover, MoxDran combination could synergistically and com- colonic bacteria. This study aimed to assess the use of pletely ͑100%͒ eradicate. A. Baumannii biofilm from CVC. There moxifloxacin/cranberry extract combination against A. baumannii is a dire need for developing novel strategies against microbial biofilm established on CVC. A. baumannii bioflim was developed biofilms on medical devices, such as the use of combination be- on silicone CVC and visualized by electron microscopy. The bio-film was treated according to the method described by Aslam et al.
tween safe anti-adherent extracts with antimicrobial agent as a Briefly, segments ͑1 cm͒ of silicone CVC ͑Cook, Inc., Blooming- catheter lock solution, to retrieve the infected vascular catheters.
ton, IN͒ were incubated in bacterial suspensions ͑106 CFU/ml͒ in The results of this study revealed a promising antibiofilm activity Mueller Hinton broth to allow biofilm formation. After incubation of moxifloxacin/cranberry extract combination for eradication of at 37°C for 24 h, segments were aseptically removed. Four sets of mature A. baumannii biofilm from CVC ͑therapeutic approach͒.
catheter segments ͑3 segments/each͒ were suspended for 6 h at Since biofilm prevention is much easier than its eradication, we 37°C in one of the following solutions: moxifloxacin ͑0.16 ug/ hypothesize that impregnation or coating of medical devices, in- mL͒, cranberry aqueous extract ͑10 mg/mL͒, Mox-Cran combina- cluding CVC, with such novel and safe combination might be an tion, or normal saline ͑NS͒ as a control. Catheter segments were outstanding tool against biofilm development ͑prophylactic ap- rinsed 3 times with NS to remove planktonic bacteria. These seg- Application of Magnetoelastic Thick Films for
When under an AC magnetic field ͑excitation field͒, the magneto- Wireless, In Vivo Monitoring of Pressure at Abdominal
elastic film generates a secondary magnetic field. Due to its mag- Aortic Aneurysm
netoelastic property, the amplitude of the secondary field varieswith applied stresses, allowing remote pressure monitoring. To E. Tan, B. Pereles, and K. Ong
eliminate noises from the excitation field, the generated secondary Michigan Technological University, Houghton, USA field is measured at twice the excitation frequency to obtain the2nd-order harmonic field, which is used for tracking the pressure According to the National Center for Health Statistics, cardio- variations. A scaled-up prototype of the pressure monitoring sys- vascular diseases remain the number one killer in the United tem was constructed and examined to demonstrate the feasibility States. Among the various types of cardiovascular diseases, the of this technology. A commercial magnetoelastic thick film, Met- aortic aneurysm is ranked number nine. The abdominal aortic an- glas 2826MB from Metglas, Inc., was attached on a polycarbonate eurysm ͑AAA͒, in particular, is an abnormal, localized dilation of substrate and covered by a thin polycarbonate protective layer.
the abdominal aorta wall caused by weakened or diseased aorta The substrate was then embedded in a plastic tube with flowing walls. One of the treatments for this disease is using an endovas- liquid to represent the condition of an aorta. Liquid pressure in the cular surgery at which an endovascular graft is delivered to the tube was altered during the experiment by restricting or relaxing aneurysm site through the femoral arteries. The deployment of the the flow channel. In this study, a 10 mmϫ 40 mm file ͑Film A͒ endovascular graft will exclude blood flow to the aneurysm, thuspreventing further expansion of the aneurysm sac. Although this and a 5 mmϫ 40 mm film ͑Film B͒ were fabricated and tested.
technique is preferred over open surgeries due to its minimal in- The amplitude of the 2nd-order harmonic field produced by the vasiveness, an event known as the endoleak, where the endovas- films was inversely proportional to the fluid pressure. It was also cular graft fails to retain the blood and leads to leakage to the shown that films with different sizes exhibited different signal aneurysm sac, may occur. Here, we are developing a novel pres- sensitivity with the smaller film ͑Film B͒ exhibited greater sensi- sure monitoring system to remotely and continuously measure the tivity. This experiment indicates that feasibility of the pressure pressure in the aneurysm sac. The main component of the system is a pressure-sensitive material, made of a magnetoelastic, mag-netically soft film attached or coated on the endovascular graft.
Journal of Medical Devices
Copyright 2009 by ASME
JUNE 2009, Vol. 3 / 027543-1
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