Background. Blood culture contamination is a clinically significant problem that results in patient harm and excess cost. Methods. In a prospective, controlled trial at an academic center Emergency ...Department, a device that diverts and sequesters the initial 1.5–2 mL portion of blood (which presumably carries contaminating skin cells and microbes) was tested against standard phlebotomy procedures in patients requiring blood cultures due to clinical suspicion of serious infection. Results. In sum, 971 subjects granted informed consent and were enrolled resulting in 904 nonduplicative subjects with 1808 blood cultures. Blood culture contamination was significantly reduced through use of the initial specimen diversion device™ (ISDD) compared to standard procedure: (2/904 0.22% ISDD vs 16/904 1.78% standard practice, P = .001). Sensitivity was not compromised: true bacteremia was noted in 65/904 (7.2%) ISDD vs 69/904 (7.6%) standard procedure, P = .41. No needlestick injuries or potential bloodborne pathogen exposures were reported. The monthly rate of blood culture contamination for all nurse-drawn and phlebotomist-drawn blood cultures was modeled using Poisson regression to compare the 12-month intervention period to the 6 month before and after periods. Phlebotomists (used the ISDD) experienced a significant decrease in blood culture contamination while the nurses (did not use the ISDD) did not. In sum, 73% of phlebotomists completed a post-study anonymous survey and widespread user satisfaction was noted. Conclusions. Use of the ISDD was associated with a significant decrease in blood culture contamination in patients undergoing blood cultures in an Emergency Department setting. Clinical Trials Registration. NCT02102087.
Abstract
Electrical impedance spectroscopy combined with Neural Networks can be a powerful combination to identify biological materials. This paper utilizes a data set containing two biological ...samples taken from different species and applies the most popular methods of dimensionality reduction. This is done in order to find out which method is able to minimize computational demand and maximize accuracy in the classification test. This paper proposes that the classic PCA method is the fastest and the most accurate under the configurations used.
Define optimum vascular catheter connector valve disinfection practices under laboratory and clinical conditions.
Prospective observational clinical survey and laboratory assessment of disinfection ...procedures.
All adult inpatients at an academic healthcare center.
In the clinical setting, contamination of needleless connectors was assessed in 6 weekly prevalence surveys in which the connector valves from central venous catheters (CVCs) in situ were cultured by pressing the connector diaphragm to an agar plate. Before culture, valves were disinfected by scrubbing the diaphragm with a 70% isopropyl alcohol pledget for 0, 5, 10, 15, or 30 seconds. In the laboratory, the diaphragms on 150 unused sterile connector valves were inoculated with 10(3), 10(5), or 10(8) colony-forming units of Staphylococcus epidermidis and allowed to dry. After disinfection of the diaphragms by scrubbing with a 70% isopropyl alcohol pledget for 0, 5, 10, 15, or 30 seconds, the valves were sampled by pressing the diaphragm to an agar plate.
In the clinical setting, 363 connector valves from patients with CVCs were sampled, and 66.7% of nondisinfected valves revealed bacterial contamination. After 5-second disinfection with an alcohol pledget, only 1 (1.4%) of 71 yielded microbial growth (P < .005). In the laboratory, at the 10(3) and 10(5) inoculum, all connector valves yielded sterile cultures when scrubbed for 5 or more seconds (P < .001). At the 10(8) inoculum, 2 (20%) of 10 connector valves yielded minimal growth of S. epidermidis.
A 5-second scrub with a 70% isopropyl alcohol pledget yields adequate disinfection of a split-septum intravascular catheter connector valve under clinical and laboratory conditions.
•A microwave assisted thermal sterilization computer simulation model (MATS-CSM) using FDTD numerical method was created.•MATS-CSM provides theoretical basis of the EM-field pattern inside the MATS ...system’s cavities.•A computer generated heating pattern in food was obtained and was experimentally verified through chemical marker method.
The microwave assisted thermal sterilization computer simulation model (MATS-CSM) was developed to improve the previous computer simulation model for the microwave assisted thermal sterilization (MATS) system. Development of the new MATS-CSM included determination of optimum heating time step, evaluation of electromagnetic field distribution and the resulting heating pattern in food, and experimental validation of heating patterns. It was determined that the minimum number of discretization that would not cause immediate divergence of the EM-heat transfer solution was 32 steps corresponding to 97mm and 5.6s of displacement and heating time for every step, respectively. Furthermore, this study successfully demonstrated the symmetrical electromagnetic field distribution between top and bottom microwave entry ports and a staggered electric field pattern from one cavity of the MATS to the next. In addition, MATS-CSM confirmed that incorporating heat diffusion in the simulation model reduces the difference in hot spot and cold spot temperature by 65%. It also confirmed that water circulation reduces the edge heating effect, as observed in experiments. The heating pattern generated by MATS-CSM was verified experimentally through a chemical marker method. Based on the percent areal cross section of the weighted average temperature, there were no noticeable differences between the heating zones generated by the MATS-CSM and by the chemical marker method. The percent areal cross section of the cold area 1, cold area 2, and hot area by MATS-CSM were 35%, 25%, and 40%, respectively, and the cold area 1, cold area 2, and hot area by chemical marker method were 35%, 30%, and 35%, respectively.
Chlorhexidine gluconate (CHG) bathing has been used primarily in critical care to prevent central line-associated bloodstream infections and infections due to multidrug-resistant organisms. The ...objective was to determine the effect of hospital-wide CHG patient bathing on healthcare-associated infections (HAIs).
Quasi-experimental, staged, dose-escalation study for 19 months followed by a 4-month washout period, in 3 cohorts.
Academic medical center.
All patients except neonates and infants.
CHG bathing in the form of bed basin baths or showers administered 3 days per week or daily. CHG bathing compliance was monitored, and the rate of HAIs was measured.
Over 188,859 patient-days, 68,302 CHG baths were administered. Adherence to CHG bathing in the adult critical care units (90%) was better than that observed in other units (57.7%, Formula: see text). A significant decrease in infections due to Clostridium difficile was observed in all cohorts of patients during the intervention period, followed by a significant rise during the washout period. For all cohorts, the relative risk of C. difficile infection compared to baseline was 0.71 (95% confidence interval CI, 0.57-0.89; Formula: see text) for 3-days-per-week CHG bathing and 0.41 (95% CI, 0.29-0.59; Formula: see text) for daily CHG bathing. During the washout period, the relative risk of infection was 1.85 (95% CI, 1.38-2.53; Formula: see text), compared to that with daily CHG bathing. A consistent effect of CHG bathing on other HAIs was not observed. No adverse events related to CHG bathing were reported.
CHG bathing was well tolerated and was associated with a significant decrease in C. difficile infections in hospitalized patients.
Radio frequency (RF) treatments have potential as alternatives to chemical fumigation for phytosanitary disinfestation treatments in the dried nut industry. To develop effective RF treatment ...protocols for almonds, it is desirable to determine heating uniformity and the occurrence of RF differential heating of insects. This study compared heating uniformity in almonds (Nonpareil) heated by RF and by forced hot air. A mathematical model suggested a 4.7 and 6.0 °C RF preferential heating of the target pest navel orangeworm (Amyelois transitella Walker) over almonds at heating rates of 5 and 10 °C min−1, respectively, for the loss factor ratio of 183 at 27.12 MHz, when the heat transfer coefficient between insects and almonds was set at 500 W m−2 °C−1. To validate the model, a gellan gel with dielectric properties similar to those of the target pest was used as a model insect. When almond kernels were heated at 27.12 MHz from 21 °C to 55 °C, the model insects were differentially heated about 4.6 °C and 5.6 °C higher than the kernel temperatures at heating rates of 5 and 10 °C min−1, respectively. These values corresponded to a heating rate for the model insect of 1.2 times greater than that for almond kernels. Slight preferential heating of insects in almonds using RF energy would improve the efficacy of large-scale RF treatments.
•Slow and non-uniform heating of almonds in hot air was improved by RF energy.•Both experiment and model showed differential heating of insect in almond.•Differential heating makes possible the development of practical RF treatment.
Determination of whether vascular catheter disinfecting antiseptic-containing caps alone are effective at decreasing microbial colonization of connectors compared to antiseptic-containing caps plus a ...5-second alcohol manual disinfection.
The study was conducted in a 718-bed, tertiary-care, academic hospital.
A convenience sample of adult patients across intensive care units and acute care wards with peripheral and central venous catheters covered with antiseptic-containing caps.
Quality improvement study completed over 5 days. The standard-of-care group consisted of catheter connectors with antiseptic-containing caps cleaned with a 5-second alcohol wipe scrub prior to culture. The comparison group consisted of catheter connectors with antiseptic-containing caps without a 5-second alcohol wipe scrub prior to culture. The connectors were pressed directly onto blood agar plates and incubated. Plates were assessed for growth after 48-72 hours.
In total, 356 catheter connectors were cultured: 165 in the standard-of-care group, 165 in the comparison group, and 26 catheters connectors without an antiseptic-containing cap, which were designated as controls. Overall, 18 catheter connectors (5.06%) yielded microbial growth. Of the 18 connectors with microbial growth, 2 (1.21%) were from the comparison group, 1 (0.61%) was from the standard-of-care group, and 15 were controls without an antiseptic-containing cap.
Bacterial colonization rates were similar between the catheter connectors cultured with antiseptic-containing caps alone and catheter connectors with antiseptic-containing caps cultured after a 5-second scrub with alcohol. This finding suggests that the use of antiseptic-containing caps precludes the need for additional disinfection.
To assess the effect of adenosine triphosphate (ATP) device measurement of hospital room cleaning and feedback of pooled results to environmental service workers (EVS) to improve cleaning efficacy.
...Nonrandomized controlled trial conducted over 20 months.
Three hospitals of varying size.
EVS workers, randomly selected on the basis of convenience sample of rooms.
Environmental cleanliness composite scores were combined with layered educational interventions and used to provide feedback to EVS workers on specific hospital units. Trends in cleaning efficacy were observed after the interventions.
Cleaning efficacy improved significantly with each intervention (P < .01) and decreased during the washout period.
The ATP detection device combined with educational feedback for EVS workers resulted in significant improvement in cleaning efficacy of the hospital room environment.
•The generators showed frequency shifts response to power settings.•The heating pattern did not changed within a possible frequency range of 900-920MHz.•Lower loss factor of circulation water ...increased the heating rate of food.•The loss factor of circulating water had no effect on the heating pattern of food.
This research studied the influence of frequency variation on heating patterns within prepackaged foods in a 915MHz single-mode microwave assisted sterilization (MATS) system consisting of four microwave heating cavities. The frequencies of the four generators powering the MATS system at Washington State University were measured at different power levels over one year. The effect of frequency shifts in the generators on heating patterns within a model food (whey protein gel, WPG) was studied through computer simulation. The simulated heating patterns were experimentally validated using a chemical marker. Our measurement results showed that a 0.5kW increase in the microwave power caused the operating frequencies of the generators to increase by 0.25–0.75MHz. The simulation results suggested that the heating pattern of WPG processed by the MATS system was not affected by the varying frequencies of generators within the operating frequency bandwidth (900–920MHz). In addition, the simulation results revealed that using deionized water as the circulation medium in the MATS system resulted in a 23–37% increase in the temperature of WPG as compared with that when using normal tap water, but did not alter the heating pattern.
Central line–associated bloodstream infections may be due to catheter connector colonization and intraluminal migration of pathogens. We assessed the colonization of the split septum catheter ...connector system, and subsequently the luer lock catheter connector system.
This was a prospective, 2 phase, quality improvement study at a tertiary referral center. Each phase of the study was performed over 3 consecutive days in hospitalized patients receiving an active infusion; first with a split septum lever lock connector and second with a luer lock connector and alcohol port protector. The connectors were inoculated onto blood agar plates and incubated. Plates were assessed for microbial growth after 48-72 hours.
In phase I, 98 (41.9%) of 234 split septum connectors yielded microbial growth. In phase II, 56 (23.1%) of 243 luer lock connectors yielded microbial growth. In phase II only, there was a significant increased rate of contamination in peripheral catheters compared with all other catheters, and the rate of contamination on the acute care wards was significantly higher when compared with the intensive care units.
Bacterial colonization of the lever lock system was unacceptably high among all catheter types and hospital locations. Transition to luer lock catheter connectors and alcohol port protectors decreased the colonization; however, colonization still remained substantial. Causation of colonization cannot be determined with these results.
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