Relative Light Units Values Research Articles

Checking the Cleanliness of Surgical Instruments Using the Adenosine Triphosphate-Bioluminescence Assay

Purpose: Cleaning is crucial for reprocessing reusable surgical instruments (RSIs). In this study, we used the adenosine triphosphate (ATP) bioluminescence method to assess the cleanliness of RSIs according to the cleaning method used.Methods: From April 3 to June 2, 2023, surgical sets, including hemostatic forceps, needle holders, operating scissors, dressing forceps, and suction tubes, that arrived at the decontamination room in the central sterile supply department of one general hospital were selected through convenience sampling. For each of the three cleaning processes, 30 cleaned RSIs were sampled with test swabs for inspection, and the relative light unit value was measured using ATP test equipment.Results: Suction tubes, hemostatic forceps, and needle holders ranked low in cleanliness (<i>x</i><sup>2</sup>=11.69, <i>p</i>=.020), and the contamination rate after mechanical cleaning was significantly lower than that after manual cleaning (<i>x</i><sup>2</sup>=31.34, <i>p</i><.001).Conclusion: Surgical instruments treated by manual processing and those containing tubes were associated with the low cleanliness. Therefore, it is necessary to check whether surgical instruments, including tubes, are manually washed at an appropriate level, and regular monitoring will be required.

Evaluation of ATP bioluminescence for rapid determination of farrowing room cleanliness after pressure washing at a commercial sow farm.

Rotavirus and other pathogenic microorganisms are known to cause scours, respiratory infection, and increased mortality, spread from pig to pig via contaminated equipment, insuffcient washing, and improperdisinfection processes in farrowing rooms on commercial sow farms. Pig producers have adopted cleaning procedures and biosecurity policies as an attempt to ensure farrowing rooms are free of infectious organisms before the next group of sows is introduced. Adenosine triphosphate (ATP) bioluminescence has been used in other industries to provide real-time feedback on surface cleanliness through the detection of ATP from organic sources. That technology may provide producers a way of objectively characterizing a farrowing room's suitability for a new group of sows to be moved into the farrowing room. Three ATP luminometers (Charm Sciences novaLUM II-X, 3M Clean Trace, and Neogen AccuPoint) were used to estimate relationships between ATP bioluminescence relative light units (RLU) and coliform plate counts (CPC). Five farrowing crate locations and the room entryway floor were swabbed to determine locations within a farrowing crate that can accurately estimate room cleanliness. Coliform plate counts were strongly correlated with Charm novaLUM II-X RLU (r = 0.70, P < 0.01). The Clean-Trace CPCs and RLU (r = 0.48, P < 0.01) were moderately correlated. There was a weak correlation between CPCs and AccuPoint RLU (r = 0.32, P < 0.01). The greatest area of surface contamination was the entryway floor and the sow feeder. Because CPCs and luminometer RLU were correlated, statistical process control charts were developed to provide cleanliness thresholds based on RLU values. Based on an adjusted 3σ from the mean RLU critical limit, 7.7% of crates for the Charm novaLUM II-X, 10.6% of crates for the 3M Clean Trace, and 0% of crates for the Neogen AccuPoint would have failed the critical limit for the sow feeder cleanliness thresholds. Using a similar approach, 11.4% of crates for the Charm novaLUM II-X, 10.5% of crates for the 3M Clean Trace, and 15.2% of crates for the Neogen AccuPoint would have failed the critical limit for the crate sorting bar cleanliness thresholds. These data suggest that ATP bioluminescence may be a reliable method to monitor cleaning effectiveness in farrowing rooms on commercial sow farms. Bioluminescence is a monitoring tool that should be used in conjunction with periodic microbial validation to monitor procedures for cleaning and disinfection.

Role of Hologic® Panther AptimaTM SARS-CoV-2 assay in the detection of SARS-CoV-2: screening or diagnostic technique?

During the multiple waves of COVID-19 suffered all over the world, having a rapid and sensitive diagnostic test has become a priority for microbiology laboratories. The AptimaTM SARS-CoV-2 transcription-mediated amplification (TMA) assay running on the Panther system (Hologic) was presented as a very good option to cover this need. To evaluate this system, 570 respiratory samples were included in the study and were processed both by the Panther (Hologic) system and by qRT-PCR (Thermo Fisher Science, Waltham, USA), current assay for the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A high number of false positives (n=76) was obtained with Panther system (Hologic), but the number of false positives decreases as the relative light units (RLU) value increases. These results show that this technique can be a good option for sample screening but checking for positive results should be mandatory, especially those with low RLU values.

SG-APSIC1045: A quantitative assessment of ATP bioluminescence on dental instruments reprocessed by automated washer-disinfector and ultrasonic machine

Objectives: Dental instruments are contaminated by blood and saliva during dental procedures. To prevent cross infection, all contaminants should be removed from the surfaces of instruments. Inadequate cleaning can hinder disinfection and sterilization process. To compare the cleaning efficacy of an automated washer–disinfector versus an ultrasonic machine on dental instruments, adenosine triphosphate (ATP) measurements were compared. Methods: From National University Polyclinic Bukit Panjang Dental Services, we collected 2 loads of 40 dental instruments previously used in dental treatments: extraction forceps, high-volume suction tips, Coupland elevators, matrix band holders, and ultrasonic scaler tips. At the point of use, gross soil was wiped from instrument surfaces with water. Each instrument was swabbed after cleaning either using a washer–disinfector or an ultrasonic machine. The relative light units (RLU) on the luminometer indicated the amount of ATP contaminants and residue bioburden present on the instruments. Results: The mean RLU values across all instruments in the washer–disinfector group was 2.5 times lower than the mean value of the instruments in the ultrasonic group (35.4 vs 89.9 RLU). This difference was statistically significant for all instrument groups except for the high-volume suction tips. The Mann-Whitney U test indicated that the RLU in the ultrasonic group was higher than the RLU for the washer–disinfector group for extraction forceps (P &lt; .001), ultrasonic scaler tips (P &lt; .023), and matrix bands (P &lt; .006). A t test indicated the same relationship for Coupland elevators (P &lt; .005). Conclusions: The mean RLU values for both cleaning methods were lower than the manufacturer’s benchmark (RLU ≤ 150), suggesting that both methods can achieve effective cleaning. However, cleaning using an automated washer–disinfector is significantly more effective than an ultrasonic machine for nonlumen instruments. The effectiveness of cleaning using ultrasonic machine varied greatly among different types of instruments with different design complexities.

Prevalence of hepatitis B and C virus infections in Lao People's Democratic Republic: The first national population-based cross-sectional survey.

Population-based seroprevalence of chronic hepatitis B and C infections has not been examined in Lao People's Democratic Republic (PDR). Therefore, this study aimed to estimate the seroprevalence of these infections in the general population of Lao PDR and perform subgroup analysis. A nationwide seroprevalence survey was conducted in Lao PDR in June 2019 using the multistage cluster sampling method. Dried blood spot samples were collected onto WhatmanTM 903 filter paper by finger prick. A chemiluminescent microparticle immunoassay was used to measure the levels of hepatitis B surface antigen (HBsAg) and hepatitis C antibody (HCV-Ab). Samples in which the HBsAg level was above 0.05 IU/ml and HCV-Ab was above the signal/cutoff ratio of 1.0 were considered positive based on comparisons with the relative light unit value of a calibration sample. A total of 1,927 samples (male: 47.3%, mean age: 23.0 years) were included in the analysis. The prevalence was estimated to be 4.2% (95% confidence interval [CI]: 2.7-6.3) for HBsAg and 1.6% (95% CI: 0.5-5.3) for HCV-Ab. Multivariable analysis revealed that those aged 20-24 years (adjusted odds ratio (AOR): 2.3, 95% CI: 1.1-4.6), those aged 25-29 years (AOR: 2.7, 95% CI: 1.3-5.6), those from the Northern region (AOR: 2.8, 95% CI: 1.2-6.6), and those who were Khmu (AOR: 3.6, 95% CI: 2.0-6.8) or Hmong (AOR: 5.0, 95% CI: 3.3-7.5) were significantly more likely to be positive for HBsAg. Although there were no statistically significant differences in the HCV-Ab prevalence according to each variable, males (2.9%, 95% CI: 0.7-10.7), those aged ≥40 years (6.1%, 95% CI: 2.1-16.8), and those from the Southern region (3.3%, 95% CI: 0.6-15.3) tended to have a higher prevalence. This novel population-based survey found differences in the prevalence of chronic hepatitis B and hepatitis C virus infections in Lao PDR according to sex, age group, region, and ethnicity; however, the results of this study should be confirmed in future studies, and relevant responses tailored for each target also need to be determined to control the transmission of hepatitis B and C infections.

4 Evaluating the Use of Leukocyte Coping Capacity as a Measure of Acute Stress in Growing Pigs During a Cycling Heating Period

Abstract The study objective was to evaluate leukocyte coping capacity (LCC) as a measure of acute heat stress in growing pigs. The LCC method utilizes an artificial challenge procedure on whole blood samples to mimic the leukocyte respiratory burst that is typically observed in response to pathogen exposure. A reduction in respiratory burst size, measured in relative light units (RLU) by chemiluminescence, indicates less LCC and greater physiological stress. Forty pigs (mean 66.7 kg BW; range: 54.9-87.5 kg) were assigned to 1 of 2 treatments, 1) thermoneutral (TN; n = 20), where pigs were maintained under thermoneutral conditions (range: 18.9-23.7 °C), or 2) heat stress (HS; n = 20), where pigs were exposed to a cycling heating period (range: 19.5-28.6 °C) for 48 h. Over each 24 h period, HS housing temperatures rose gradually from 0800-1200 h, were maintained at a maximal level until 1600 h, and gradually returned to thermoneutral temperatures by 1800 h. Blood (2 mL) was collected from each pig at 0 (0800 h), +4, +8, +24 and +48 h relative to the start of the experiment. Whole blood samples were challenged with phorbol 12-myristate 13-acetate to induce a respiratory burst, which was measured using a portable luminometer. Data were analyzed using the MIXED procedure in SAS 9.4. An hour effect was observed (P &amp;lt; 0.001), where RLU values increased linearly throughout the experimental period. However, RLU did not differ between TN and HS pigs (57.9 ± 4.1 vs. 55.4 ± 4.1 RLU, respectively; P = 0.67). Additionally, no treatment by hour interaction was observed at any timepoint (P = 0.48). Overall, a cycling heating period did not alter LCC in growing pigs. Future studies should evaluate whether LCC is effective for measuring additional properties of heat stress, such as greater temperatures or chronic periods of exposure.

Hygienic monitoring in long-term care facilities using ATP, crAssphage, and human noroviruses to direct environmental surface cleaning

BackgroundNorovirus and C. difficile are associated with diarrheal illnesses and deaths in long-term care (LTC) facilities and can be transmitted by contaminated environmental surfaces. Hygienic monitoring tools such as adenosine triphosphate (ATP) bioluminescence and indicators of fecal contamination can help to identify LTC facility surfaces with cleaning deficiencies. MethodsHigh-touch surfaces in 11 LTC facilities were swabbed and tested for contamination by norovirus, a fecal indicator virus, crAssphage, and ATP which detects organic debris. High levels of contamination were defined as log ATP relative light unit values or crAssphage log genomic copy values in the 75th percentile of values obtained from each facility. ResultsOver 90% of surfaces tested positive for crAssphage or gave failing ATP scores. Norovirus contamination was not detected. Handrails, equipment controls, and patient beds were 4 times more likely than other surfaces or locations to have high levels of crAssphage. Patient bed handrails and tables and chairs in patient lounges had high levels of both ATP and crAssphage. ConclusionsSurfaces with high levels of ATP and crAssphage were identified. Quantifying levels of contamination longitudinally and before and after cleaning might enhance infection prevention and control procedures for reducing diarrheal illnesses in LTC facilities.

Feedback of ATP measurement as a tool for reducing environmental contamination in hospitals in the Dutch/Belgian border area.

A two-phase prospective intervention study. The objective of this study was to determine if feedback of adenosine triphosphate (ATP) measurements decreases environmental contamination within hospitals in the Dutch/Belgian border area. Standardized ATP measurements were conducted in nine hospitals on pre-defined fomites. Four different fomite groups were defined: medical devices, patient-bound materials, ward-bound materials and sanitary items. ATP results were reported in relative light unit (RLU), RLU >1000 was considered as 'not clean.' Two rounds of ATP measurements were conducted. After the first round of ATP measurements, results were provided to the wards and cleaning staff. The second round of ATP measurements was performed one year later. The amount of surface contamination before and after the feedback was compared. In total 1923 ATP measurements were performed. Before feedback 960 ATP measurements were conducted and after feedback 963 were conducted. The overall median reduction in RLU was 381 (P<0.001), from 568 before feedback to 187 afterward. In each hospital there was a reduction of the median RLU after feedback. Substantial reductions in RLU values were found after feedback of ATP measurements. Feedback of ATP measurement in itself was associated with a major reduction of surface contamination in hospitals.

Assessing Accumulation of Organic Material on Rodent Cage Accessories

According to the 8th edition of the Guide for the Care and Use of Laboratory Animals (the Guide), rodent cage accessories,such as filter tops, should be sanitized at least once every 2 wk. We performed a study to test the hypothesis that organic contamination(measured by ATP content, expressed as relative light units (RLU)) of cage accessories (wire bar inserts and filter top lids) does not differ at 2 wk (14 d) as compared with 30, 60, and 90-d time points after cage change even when in constant use. An additional time point for filter top lids of 180 d after cage change was also evaluated. Eight groups were studied: the wire bar inserts and filter top lids used for mice and rats, in both static and individually ventilated cages (IVC). When analyzing data from both mouse and rat static and IVC caging, we found that the mean RLU values for mouse IVC and rat static and IVC cage components were below 100,000 RLU at the 14-d time point. The mean value for the mouse static groupwas slightly above 100,000 RLU at this time point. Based on this observation, we considered 100,000 RLU to be an appropriate actionable level. We concluded that changing wire bar inserts at least every 14 d, as recommended in the Guide for sanitizing these components in mouse and rat static cages, may be considered acceptable. This interval could be extended for mouse and rat IVC cages up to 90 d while remaining below this limit. Filter top lids for mouse static cages should be changed at least every 30 d, but static rat and IVC mouse/rat filter top lids could be changed up to every 180 d, while still staying below this actionable level of contamination.

Mechanism of heparin interference in detection of LIAISON® Rubella IgM

AimsTo investigate the effects of heparin in detection of LIAISON® Rubella IgM (Rub-M) and the mechanism of interference. MethodsDifferent concentrations of lithium heparin and sodium heparin were added to ten serum samples. The relative light units (RLU) value of Rub-M was measured using the LIAISON XL detection system. Different levels of IgM serum were incubated with magnetic particle in Rub-M detection kit at 4 °C for 4 h, blocking anti-human IgM-specific antibodies coated on the surface of magnetic particle. Separately, the rubella virus antigen in Rub-M detection kit was replaced by phosphate-buffered saline (PBS). The RLU values of LIAISON® Rub-M of original serum and serum containing various concentrations of heparin were measured after the above two different treatments. ResultsThe RLU value of LIAISON® Rub-M increased with the increase of heparin content lower than 40 IU/mL, and reached a peak value at 40–50 IU/mL. The RLU value of LIAISON® Rub-M then decreased with the decrease of heparin concentration. When rubella virus antigen was replaced by PBS, the RLU value of LIAISON® Rub-M of serum samples containing 40 IU/mL heparin decreased significantly. The blocking concentration of IgM increased gradually, and the RLU value of LIAISON® Rub-M of seven serum samples containing 40 IU/mL heparin also decreased gradually. ConclusionPlasma with heparin cannot be used to the detection of LIAISON® Rub-M. Heparin may participate in the reaction by binding with rubella virus antigen and anti-human IgM-specific antibodies coated on the surface of magnetic particle, thus affecting the detection results.

ATP measurement as an objective method to measure environmental contamination in 9 hospitals in the Dutch/Belgian border area

BackgroundThe objective of this study was to determine the level of environmental contamination in hospitals in the Dutch/Belgian border area, using ATP measurements.DesignA cross-sectional observational survey.MethodsStandardized ATP measurements were conducted in 9 hospitals on 32 hospital wards. Thirty pre-defined surfaces per hospital ward were measured with the 3 M Clean Trace NG luminometer. Results are displayed in relative light units (RLU). RLU > 1000 was considered as “not clean.” Differences in RLU values were compared between countries, hospitals, fomite groups and medical specialties.ResultsA total of 960 ATP measurements were performed, ranging from 60 up to 120 per hospital. The median RLU-value was 568 (range: 3–277,586) and 37.7% of the measurements were rated as not clean (RLU > 1000). There were significant differences between countries, hospitals and fomite groups.ConclusionATP measurements can be used as a more objective approach to determine the level of environmental contamination in hospitals. Significant differences in ATP levels were found between hospitals and between countries. Also, substantial differences were found between different fomite groups. These findings offer potential targets for improvement of cleanliness in healthcare facilities.

Study of the self-stabilization ability of Tzatziki (a traditional Greek ready-to-eat deli salad)

Traditional Greek yogurt-based salad Tzatziki is one of the most popular ready-to-eat deli salads in Greece. The objective of this study was to estimate the microbial stability of Tzatziki, with and without chemical preservatives, using a rapid method. Determination of the microbial count was carried out using the bioluminescence method (ATP) and traditional microbiological analysis, plate-counting method (CFU) in various batches of the final product of Tzatziki. The results showed that the Tzatziki salad without preservatives initially gave higher relative light units (RLU) values (79,532) than the same salad with preservatives (43,198) because the potassium sorbate and the sodium benzoate, used in recipe, appeared to suspend the action of microorganisms. After incubation in two different substrates, MacConkey and Sabouraud, the Tzatziki salad without preservatives gave higher RLU values (9,488 and 16,176, respectively) than the salad with preservatives (12,780 and 12,005, respectively). In the two selective substrates, differences appeared between the two methods of microbial count (RLU and CFU). While RLU values were roughly at the same level, the CFU values presented significant differences ( p < 0.05). It was also shown that there was a strong correlation ( R 2 = 0.93-0.95) between bacterial counts estimated by traditional CFU and ATP methods. As expected, the dominant microbial population in Tzatziki was Lactobacillus spp., originated from yogurt. Coliforms and yeasts were not able to survive in this environment. Generally, according to the results, Greek traditional Tzatziki salad was a microbial stable product and the bioluminescence method could be a rapid method to determine its microbial state.

Study of the self-stabilization ability of Tzatziki (a traditional Greek ready-to-eat deli salad)

Traditional Greek yogurt-based salad Tzatziki is one of the most popular ready-to-eat deli salads in Greece. The objective of this study was to estimate the microbial stability of Tzatziki, with and without chemical preservatives, using a rapid method. Determination of the microbial count was carried out using the bioluminescence method (ATP) and traditional microbiological analysis, plate-counting method (CFU) in various batches of the final product of Tzatziki. The results showed that the Tzatziki salad without preservatives initially gave higher relative light units (RLU) values (79,532) than the same salad with preservatives (43,198) because the potassium sorbate and the sodium benzoate, used in recipe, appeared to suspend the action of microorganisms. After incubation in two different substrates, MacConkey and Sabouraud, the Tzatziki salad without preservatives gave higher RLU values (9,488 and 16,176, respectively) than the salad with preservatives (12,780 and 12,005, respectively). In the two selective substrates, differences appeared between the two methods of microbial count (RLU and CFU). While RLU values were roughly at the same level, the CFU values presented significant differences (p &lt; 0.05). It was also shown that there was a strong correlation (R2 = 0.93-0.95) between bacterial counts estimated by traditional CFU and ATP methods. As expected, the dominant microbial population in Tzatziki was Lactobacillus spp., originated from yogurt. Coliforms and yeasts were not able to survive in this environment. Generally, according to the results, Greek traditional Tzatziki salad was a microbial stable product and the bioluminescence method could be a rapid method to determine its microbial state.

The impact of an ambulance vehicle preparation service on the presence of bacteria: a service evaluation.

Introduction:Around 300,000 patients a year in England acquire a healthcare-associated infection (HAI) while being cared for by the NHS. The contribution from NHS Ambulance Services is not known, but previous studies have identified the presence of pathogenic bacteria such as Methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus, including resistant strains in some cases, inside ambulances. To improve ambulance cleanliness, Yorkshire Ambulance Service NHS Trust (YAS) piloted an Ambulance Vehicle Preparation Service (AVPS) at two ambulance stations, where staff were tasked with ensuring every ambulance at these stations was cleaned every 24 hours.Methods:Adenosine triphosphate (ATP) bioluminescence testing was conducted on 16 ambulances at the two pilot AVPS stations and on 18 ambulances at four ‘business as usual’ (BAU) ambulance stations using a Hygiena SystemSURE luminometer. Swabs were obtained from 10 pre-selected locations inside each ambulance.Results:Between November 2016 and August 2018, a total of 690 swabs were obtained and recorded from 34 ambulances. Overall, median relative light unit (RLU) values for both groups were < 100, with only the BAU group having an upper quartile value > 100. However, when stratified by swabbing area, three areas had a median RLU of > 100 in the BAU group: suction unit handle, steering wheel and airway seat shelf. In addition, the upper quartile RLU values for the grab rail above the stretcher and the passenger seat in the BAU group were also > 100. No swab areas had a median RLU > 100 in the AVPS group.Conclusion:A dedicated AVPS results in better cleaning of ambulance vehicles than the existing cleaning system utilising operational crews. The areas most likely to be contaminated are the suction unit handle, steering wheel, airway seat shelf and grab rails. The position of equipment and the materials that equipment are constructed from should have infection prevention and control (IPC) as a consideration.

Abstract PR05: Estrogenic activity is associated with race/ethnicity and Indigenous American ancestry among San Francisco Bay Area women

Abstract The incidence of breast cancer in the U.S. varies by race/ethnicity. Furthermore, in Hispanic women, breast cancer risk is higher among women with low Indigenous American ancestry compared to those with high Indigenous American ancestry and in U.S.-born compared to foreign-born women. In a previous pilot study among foreign-born and U.S.-born Mexican women, we found that plasma estrogenic (E) activity was associated with genetic ancestry and years of U.S. residence, suggesting the possibility of a hormone-related pathway for the observed differences in breast cancer risk. In the present study, we examined the association between E activity and genetic ancestry in a larger sample of Hispanic women. We also evaluated the association between E activity, demographic factors, and breast cancer risk in non-Hispanic Black (NHB) and non-Hispanic White (NHW) women. We utilized a receptor-mediated Chemical-Activated Luciferase gene eXpression (CALUX) assay for the assessment of total activity profiles against estrogen receptors (ER) in human plasma, which captures levels of both endogenous and exogenous estrogenic compounds. Results were expressed in relative light units (RLUs), with higher RLU values reflecting greater E activity in plasma. ER activation was measured in plasma samples of 329 Hispanic, 100 NHBs, and 74 NHW women who participated as controls in the San Francisco Bay Area Breast Cancer Study (SFBCS). The participants ranged in age from 35 to 79 years, though the study was composed predominantly of postmenopausal women. Multivariable regression models included race/ethnicity, age at blood draw, height, body mass index (BMI), neighborhood socioeconomic status (SES), and alcohol intake. In the univariate model that included all women (n=503) and race/ethnicity as the independent predictor, Hispanics had 24% lower E activity (p=0.061) and NHBs had 36% higher activity (p=0.047) compared to NHWs. In the multivariable model, Hispanics still showed lower E activity levels (34%, p=0.009), but the difference with NHBs and NHWs was no longer statistically significant (p=0.493). After adjustment for levels of two endogenous estrogens, estradiol and estrone, in a subset of samples (n=260), Hispanics continued to show 20% lower E activity compared to NHWs. In addition, when BMI is categorized into tertiles consisting of normal (&amp;lt;25 kg/m2), overweight (25-30 kg/m2), and obese (BMI &amp;gt;30 kg/m2) women, we found that obese women had 73% higher E activity compared to those with normal BMI (p&amp;lt;0.001) and overweight women had 46% higher activity (p=0.006). Among the Hispanic women, we confirmed the previously observed negative association between E activity and Indigenous American ancestry, which is consistent with the observation that Hispanic women with high Indigenous American ancestry have lower risk of developing breast cancer. Overall, our study suggests that observed associations between race/ethnicity, genetic ancestry and BMI with breast cancer risk could be partly due to the mediating effect of endogenous estrogens as well as to the effect of exogenous estrogen-like compounds. Citation Format: Sylvia S. Sanchez, Phum Tachachartvanich, Heather Ruiz, Frank Z. Stanczyk, Scarlett Lin Gomez, Esther M. John, Martyn T. Smith, Laura Fejerman. Estrogenic activity is associated with race/ethnicity and Indigenous American ancestry among San Francisco Bay Area women [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr PR05.

Bacterial Contamination of CT Equipment: Use of ATP Detection and Culture Results to Target Quality Improvement

This study aimed to evaluate the use of an adenosine triphosphate (ATP) monitoring system to minimize surface contamination on inpatient computed tomography (CT) scanners. The bore, table, and wrap of two quaternary care inpatient CT scanners (load/scanner: ~ 30-40 CT examinations/day) were assayed with bacterial cultures and an ATP detection system during six prospective iterative plan-do-check-act improvement cycles from January 6, 2016 to October 12, 2016. Per-cycle sampling was for eight consecutive weekdays. ATP detection was expressed as relative light units (RLUs) through a luciferase reaction, with >350 RLU considered contaminated per manufacturer recommendations. Culture swabs were placed into 6.5% NaCl broth, a Staphylococcus enrichment broth, and incubated aerobically at 37°C for 48 hours. Positive broths were plated to chromogenic Staphylococcus media. Culture rates (Fisher exact test) and RLU values (Mann-Whitney U test) were compared. In Cycle 1, both culture results and median RLU values indicated the wrap was the most contaminated item (positive culture rate: 63% [10/16], median RLU interquartile range: 173 [IQR: 56-640]); however, RLU values were not predictive of per-sample culture results (P = .36). Following iterative improvements, RLU values at Cycle 6 were significantly lower than at peak (P = .02-.04) and within manufacturer's recommendations: all samples: 45 (IQR: 16-87), bore: 26 (IQR: 0-51), table: 68 (IQR: 21-89), wrap: 47 (IQR: 38-121). The Velcro wrap is the most contaminated item on a CT scanner, and special processes may be needed to ensure adequate cleansing. ATP detection is a crude surrogate for bacterial culture results but benefits from speed, reduced cost, and greater statistical power.

Residual contamination and bioburden after reprocessing of single‐use endoscopic ultrasound needles: An ex vivo study

Endoscopic ultrasound (EUS) aspiration needles are single-use devices. However, in many centers, because of cost-constraints, these devices are reused multiple times. We studied microbiological contamination and bioburden on reprocessed needles to evaluate whether these devices can be successfully sterilized. We studied 10 EUS needles each of 19G, 22G, and 25G in size, and five 22-G ProCore needles. After initial use, each needle was reprocessed by a standardized protocol. We used standard microbiological cultures, as well as ATP bioluminescence technique to quantify bioburden as relative light units (RLU). We defined significant soil contamination by RLU values >200. We also used extractant fluid to disrupt cell membranes in an attempt to enhance ATP detection. We found culture positivity in 3/34 (8.8%), and detectable bioburden on the exposed surface of 33/35 (94.3%), and inside lumen of 29 (82.9%) reprocessed FNA needles. Significant bioburden was found in three (8.6%) and two (5.7%) needles on the surface and lumen, respectively. We found that use of extractant fluid enhanced detection of bioburden. Larger (19G) needles had higher surface contamination (P=0.016), but there was no relation of luminal contamination with needle diameter (P=0.138). Sheath design and presence of side bevel did not influence extent of contamination. There was significant correlation between the surface and intraluminal bioburden (P<0.001). There is significant bioburden in reprocessed EUS needles; standard microbiological cultures have low sensitivity for detection of needle contamination. We have provided objective evidence for the futility of reprocessing attempts, and practice of EUS needle reuse should be discontinued.

The Use of ATPase Monitoring to Determine Endoscope Bioburden and Assure Satisfactory Manual Cleaning

Introduction: Recent multidrug resistant organism outbreaks linked to endoscopy have prompted re-examination of endoscope reprocessing. The steps of reprocessing include manual cleaning, automatic reprocessing, and drying. The manual cleaning phase is the most vulnerable to contamination as it is prone to human error. Many centers have turned to culturing instruments to assure that their instruments have been successfully disinfected. We report applying the “ATPase” assay to our reprocessing method. This technology is routinely used in hospitals to assure cleanliness of work surfaces but it is sparingly used in the field of endoscopy. The system provides real-time, quantitative data by utilizing bioluminescence of adenosine triphosphate (ATP) as an indirect measure of bacterial presence or bioburden. There is no standardized method of ATPase use in endoscopy. Methods: Data was collected from patient used colonoscopes and gastroscopes during a 3 month trial period. Data was then collected over the following 12 months after the reprocessing method was reformed. ATP samples were obtained after intruments were manually cleaned, just before they were placed into an automatic reprocessor. A collection technique proposed by a leading investogator in the field was used to obtain channel and surface samples. The 3M™ Clean-Trace ATP Surface Test was used to measure the presence of ATP. A threshold of 200 relative light units (RLU) was used to determine if endoscopes “passed”. Instruments were re-cleaned if they exceeded 200 RLU. Results: A total of 618 tests were performed (310 gastroscopes) between March 2013 and May 2014. Surface cleaning was effective in 98.5% of gastroscopes and 96.9% of colonoscopes. Samples obtained from the biopsy channel were quite different with 95.4% of colonoscopes passing and only 64.2% of gastroscopes passing. The manual cleaning process was then modified and the enzymatic detergent used to flush endoscope channels was changed. During the 12 month observation period, over 90% of all gastroscopes and colonoscopes passed. Conclusion: Initial results showed that gastroscopes were more difficult to clean, likely due to biofilm on complex structural elements and increased mucus encountered during EGD. After modifying the reprocessing technique, the RLU values for gastroscopes significantly improved. We provide this data to aid in the standardization of the ATPase assay sampling method as a routine method of manual cleaning phase monitoring at endoscopy centers worldwide.

The adenosine triphosphate method as a quality control tool to assess ‘cleanliness’ of frequently touched hospital surfaces

The adenosine triphosphate (ATP) method is widely accepted as a quality control method to complement visual assessment, in the specifications of requirements, when purchasing cleaning contractors in Swedish hospitals. To examine whether the amount of biological load, as measured by ATP on frequently touched near-patient surfaces, had been reduced after an intervention; to evaluate the correlation between visual assessment and ATP levels on the same surfaces; to identify aspects of the performance of the ATP method as a tool in evaluating hospital cleanliness. A prospective intervention study in three phases was carried out in a medical ward and an intensive care unit (ICU) at a regional hospital in mid-Sweden between 2012 and 2013. Existing cleaning procedures were defined and baseline tests were sampled by visual inspection and ATP measurements of ten frequently touched surfaces in patients' rooms before and after intervention. The intervention consisted of educating nursing staff about the importance of hospital cleaning and direct feedback of ATP levels before and after cleaning. The mixed model showed a significant decrease in ATP levels after the intervention (P < 0.001). Relative light unit values were lower in the ICU. Cleanliness as judged by visual assessments improved. In the logistic regression analysis, there was a significant association between visual assessments and ATP levels. Direct feedback of ATP levels, together with education and introduction of written cleaning protocols, were effective tools to improve cleanliness. Visual assessment correlated with the level of ATP but the correlation was not absolute. The ATP method could serve as an educational tool for staff, but is not enough to assess hospital cleanliness in general as only a limited part of a large area is covered.

Analysis of object surface cleanness and relative factors in cardiac surgical ICU

Objective To assess the effect of existing cleaning methods applied in cardiac surgical intensive care unit, analyze potential danger and provide evidence to support clean processes in the future. Methods Each patient′s bed unit was defined as a sample and the frequency of hand-to-bed contact and the extent of patient-to-bed contact were assessed.Totals of 15 monitoring surface on each sheet were taken after sterilization within 24 hours and the Relative Light Units(RLU) of the monitoring surface values were compared with Adenosine Triphosphate (ATP) bioluminescence techniques. Results RLU values were more than 500 on bedside table surface, bed block, ECG buttons, micro pump surface, pressurized infusion ball surface and crank bed. RLU values were between 250 and 500 on nurses′ small table surface, breathing machine buttons, rulers and stethoscope surface. RLU values were less than 250 on treatment plate, footboard, pump lines and vacuum tube surface. Conclusions Hand hygiene plays a significant role in daily life. It is important to strengthen routine hand hygiene publicity and education, and monitoring and supervision can be used as an effective measure to improve the surface cleanliness of objects. Key words: ICU; Adenosine triphosphate bioluminescence techniques; Cleanliness