Significant removal of bacterial biofilm induced by multiple-Short ranges of electric interventions.

BACKGROUND: Biofilm-related infections are serious problems in the Orthopedics field, and Staphylococcus aureus are the most popular causative agents of bacterial infections associated with arthroplasty. Several studies demonstrated a synergistic effect of the electric intervention (EI) and the antibiotic administration in killing bacteria in biofilm; however, a constant, long-time EI was needed. In the present study, the effective removal of biofilm formed with S. aureus on a titanium ring by multiple times of one minute-EI was observed and described. METHODS: A methicillin-sensitive S. aureus clinical isolate was used to form biofilm on a titanium ring. After applying a series of EI with various combinations of the frequencies and timings, the amount and principal components of biofilms were assessed with crystal violet staining, live bacterial cell count, and fluorescence staining with confocal laser scanning microscopy. RESULTS: More than 60% biofilm removal was observed in the 2-time EI applied at 24 (1) and 72 (3) h (days) post bacterial exposure (PBE) and in the 3-time EI at 0 (0), 24 (1), and 72 (3) h (days) PBE, or at 24 (1), 48 (2), and 72 (3) h (days) PBE. The live bacterial cell numbers, the proportion of live and dead cells, and the amount of extracellular polysaccharide substances (EPS) of biofilm were similar with or without EI. It was assumed that an excess amount of the biofilm removal shown in the several EI was not attributed to the effect of the electrolysis. CONCLUSIONS: The effective removal of biofilm was observed when multiple times 1 min EI was applied without any changes in the proportion of live and dead bacteria or the amount of EPS. The mechanisms to explain extra biofilm removal remain to be elucidated.

Multijurisdictional Outbreak of Enterohemorrhagic Escherichia coli O157 Caused by Consumption of Ready-to-Eat Grilled Skewered Meat in Niigata, Japan.

Enterohemorrhagic Escherichia coli O157 (EHEC) causes severe complications such as hemolytic uremic syndrome. Contaminated ready-to-eat (RTE) food is one of the vehicles of multijurisdictional outbreaks of foodborne disease worldwide. Multijurisdictional (covering cities, towns, and villages) outbreaks of EHEC are usually linked to an increase in cases, and here we describe such an outbreak involving 29 cases in October 2017 in the Niigata Prefecture. After prefecture-wide active case finding, we conducted a case-control study of 29 cases with eligible data who tested positive for EHEC. To determine the association of the outbreak with risk factors, we compared these cases with 38 controls selected from family and acquaintances who were both symptom free and tested negative for EHEC. The largest number of cases was in the 20-29-year age group (7/29; 24%) and most were women (20/29; 69%). All 29 cases had an identical or similar multilocus variable number tandem-repeat analysis (MLVA) profile. Of these, 76% (22/29) had consumed some type of grilled skewered meat. Also, 69% (20/29) had consumed grilled skewered meat produced by company X. EHEC infection was strongly associated with the consumption of grilled skewered meat produced by any food processing company (odds ratio [OR] = 11.8, confidence interval [95% CI]: 3.7-37.4) and by company X (OR = 9.8, 95% CI: 3.2-30.7). At company X, the skewered meat was grilled to 95°C and then removed from the grilling area to meat trays. The meat trays were not sufficiently washed and disinfected. Testing indicated that the facility was negative for EHEC but four asymptomatic employees tested positive for EHEC. Company X was temporarily closed and voluntarily recalled the foods. We recommend that all employees sufficiently wash and disinfect meat trays to prevent contamination of RTE food, avoid cross-contamination of grilled skewered meat through the environment by regularly cleaning the facility, and appropriately practice self-health care.

Inhomogeneous vasodilatory responses of rat tail arteries to heat stress: evaluation by synchrotron radiation microangiography.

Tail blood flow is crucial for dissipating body heat in rats. Angiographies are convenient tools to evaluate tail circulation. However, conventional angiographies do not have sufficient sensitivity or spatial resolution for small vessels. Recently, we developed a novel microangiographic system using monochromatic synchrotron radiation and a high-definition video camera system. Here, we report an evaluation of rat tail circulation under heat stress using the synchrotron radiation microangiographic system. We performed an experiment using the microangiography of the caudal artery before and after heating up WKAH/HkmSlc rats to rectal temperature of 39 degrees C. The images were digitized and temporal subtraction was performed, and the diameters of caudal arteries were evaluated. After heating, the medial caudal artery was markedly dilated (320 +/- 53 to 853 +/- 243 micro m in diameter, p<0.001), while no significant change was observed in the lateral caudal arteries (139 +/- 42 to 167 +/- 73 micro m) and segmental anastomosing vessels. The heat stress allowed for visualization of the superficial caudal arteries with a diameter of approximately 60 micro m, not visible prior to heating. Thus, synchrotron radiation microangiography demonstrated that the rat tail possessed dual sets of arteries; one set was highly sensitive to heat-induced vasodilation (medial caudal artery and superficial caudal arteries) and the other set was less sensitive (lateral caudal arteries and segmental anastomosing vessels).

Search for appropriate experimental methods to create stable hind-limb ischemia in mouse.

OBJECTIVE: Stable animal models for refractory peripheral arterial disease are not established. A standardized animal model of hind-limb ischemia is required upon searching effective treatment for this condition. The aim of the study is to verify previously used hind-limb ischemia models to find a standard method. METHODS: Using Balb/ca mice six various methods of inducing hind-limb ischemia were applied and two weeks after operation degree of ischemic damage were examined. Six methods include V group, A group, AV group, A-strip group, AV-strip group and Prox-A group (refer the text). RESULTS: Degree of ischemia was evaluated macroscopically by judging toes, foot, knee, and total hind-limb necrosis. We found that severity of damage was markedly different among different methods. Furthermore the severity of necrosis was not uniform even in the same method group. CONCLUSIONS: The A-strip group in which the femoral artery from the bifurcation of the deep femoral artery to the saphenous artery was stripped appears to be suitable as a stable severe ischemia model. The A group in which the femoral artery were cut just below the bifurcation of the deep femoral artery appears to be suitable as a chronic mild ischemia model.

Salvage operations of free tissue transfer following internal jugular venous thrombosis: a review of 4 cases.

The internal jugular vein (IJV) is used as the optimal recipient for free-tissue transfer in reconstruction following modified radical neck dissection. Some reports documented rare cases of flap compromise following IJV thrombosis, but large sample studies are few. We present cases of emergent exploration and an analysis of factors to improve salvage rates of compromise due to IJV thrombosis. From a survey of 756 patients, four developed congestion due to IJV thrombosis and returned to the operating room. A restrospective analysis was made from the case records. This represents a rate of 0.5% for the entire series. Three flaps survived,and one failed. Detection of compromise ranged from 7-25 h postoperatively. All four IJVs recovered to provide adequate drainage after thrombectomy. While flap compromise following IJV thrombosis is rare, careful observation and early exploration are crucial for salvage, as in other microvascular venous crises.