Adenosine Triphosphate Bioluminescence Assay Research Articles

Can the adenosine triphosphate (ATP) bioluminescence assay be used as an indicator for hospital cleaning? - A pilot study.

In hospital cleaning, there is currently no standard for uniform monitoring of surface cleaning, either in Germany or internationally. One possibility for monitoring is the use of so-called objective methods for checking cleaning performance (e.g. fluorescence or adenosine triphosphate (ATP) method). The aim of the study was to monitor and evaluate the implementation of the adenosine triphosphate (ATP) bioluminescence assay as a cleaning indicator in everyday hospital cleaning, in order to verify its utility and effectiveness. In three phases, five frequently touched surfaces were examined with the ATP bioluminescence assay at different time points. 846 measurements were performed on the dermatology ward of a university hospital (phase 1), 1,350 measurements were performed on five different wards of the university hospital (phase 2), and 1,044 measurements were performed on five wards of another large hospital (phase 3). For this purpose, one structurally old and one structurally new ward as well as an intensive care unit (ICU), an outpatient clinic and a radiology department were selected for phases 2 and 3. With the ATP bioluminescence method, we were able to demonstrate a reduction in values after cleaning: before cleaning mean of ATP, 907 relative light units (RLU) (95% confidence interval [CI] 777; 1,038); after cleaning mean=286 RLU (CI=233; 495) (phase 1) and by intervention (five hours after daily cleaning mean=360 RLU (CI=303; 428); five hours after daily cleaning and two additional cleanings mean=128 RLU (CI=107; 152) (phase 3). The ATP values increased five hours after cleaning in phases 1 and 2, and eight hours after cleaning in phase 3. The structurally old wards had the highest ATP content, the ICU and the radiology department, among others, the lowest. In all phases, door handles showed both a reduction after cleaning or intervention and a subsequent increase in ATP values. Chair armrests, examination tables and door handles had high ATP values overall. The study shows ward differences both for cleaning effects and for the soiling characteristics of surfaces during the course of the day. In addition, it demonstrates the benefit of intermediate cleaning twice a day. It is noteworthy that structurally old stations and older inventory were more heavily soiled and, in some cases, more difficult to clean. The results show that the ATP bioluminescence method is suitable for detecting cleaning effects and can be used in everyday clinical practice for simple cleaning monitoring. Furthermore, it enables the detection of risk surfaces and easy-to-clean surfaces with significant re-soiling.

The effectiveness of disinfection protocols in osteopathic family medicine offices.

Healthcare-associated infections (HAIs) pose a substantial public health threat. Despite significant strides tocurb HAIs in hospital environments, outpatient settings have not received the same degree of attention. Given their emphasis on holistic, patient-centered care, osteopathic family medicine offices are pivotal in both disease prevention and comprehensive patient treatment. The importance of simple yet effective disinfection protocols, such as thorough cleaning between patient appointments, cannot be overstated in these settings because they are integral to minimizing disease transmission. This study aims to assess the effectiveness of the current disinfection protocols in osteopathic family medicine offices. A cross-sectional study evaluating disinfection practices on 18 examination tables in an osteopathic family medicine office was conducted. Two high-touch surfaces (midtorso region and table edge) were examined. Initial swab samples were collected after morning disinfection by Environmental Services, and terminal swab samples were gathered after day's-end disinfection by the medical staff. Adenosine triphosphate (ATP) bioluminescence assays were performed utilizing AccuPoint Advanced HC Reader, which quantified ATP, indicating contamination levels in the samples. The higher the ATP levels found in a sample, the greater the amount of biological contamination. All samplers were handled and tested as per manufacturer's instructions. Apreliminary trial was conducted to confirm the internal validity of ATP bioluminescence measurements. The statistical analysis involved Shapiro-Wilk and Wilcoxon signed-rank tests, with significance set at p<0.05. Cohen's d test was utilized to calculate the effect size, identifying meaningful differences in initial and terminal swab sample relative light units (RLUs). The midtorso region demonstrated an 11.1 % increase in failure rate after terminal disinfection when compared to initial disinfection. A Wilcoxon signed-rank testrevealed a median estimated pathogen level forthemidtorso region that was higher after terminal disinfection (median, 193 RLUs; range, 1-690 RLUs; n=18) compared to initial disinfection (median, 134 RLUs; range,4-946 RLUs; n=18). However, this increase was not statistically significant, p=0.9124, with a small effect size, d=0.04. The edge showed no change in failure rate after terminal disinfection, maintaining a 100 % failure rate both before and after disinfection. However, the Wilcoxon signed-rank test revealed a slight reduction in the median estimated pathogen levels after terminal disinfection (median, 2095 RLUs; range, 891-5,540 RLUs; n=18) compared to before disinfection (median, 2,257 RLUs; range, 932-5,825 RLUs; n=18). However, this reduction wasnot statistically significant, p=0.61, with a small effect size, d=0.12. The findings from this study reveal a substantial disparity in outcomes between the two sample locations, midtorso and edge. The midtorso demonstrated arelatively low failure rate in both initial and terminal swab samples, indicating successful outcomes. In contrast, the edge consistently displayed a 100 % failure rate, emphasizing the need for more care and attention when cleaning the edge of the examination to ensure better outcomes. By prioritizing adequate disinfection protocols, including thorough cleaning between patients, osteopathic family medicine offices can more effectively prevent disease transmission and promote patient safety.

A novel strategy for bioaerosol rapid detection based on broad-spectrum high-efficiency magnetic enrichment and separation combined with ATP bioluminescence

Bioaerosol detection technology represented by laser-induced fluorescence (LIF) cannot effectively detect bioaerosols in the presence of interferents such as plant-derived smoke, industrial waste gas, pollen and pollen debris which can produce strong non-biological fluorescence interference. To overcome this drawback, in this study, a novel method based on broad-spectrum high-efficiency magnetic enrichment and separation combined with adenosine triphosphate (ATP) bioluminescence was proposed for Escherichia coli (E. coli) bioaerosols rapid detection. First, E. coli bioaerosols mixed with interferents were collected. Core-shell Fe3O4@Polydopamine@Polyethyleneimine magnetic particles were used as bioaerosol enrichment materials to enrich E. coli bioaerosol sampling solutions. Subsequently, an ATP bioluminescence assay was performed to determine the concentration of E. coli. A linear relationship was observed between ATP bioluminescence intensity after enrichment and the E. coli bioaerosol concentration in the range of 870–49,098 particles per liter; the bioluminescence intensity measured after enrichment was significantly higher than that before enrichment, and this enrichment method provide a 6-fold better sensitivity in bioaerosol detection. More importantly, this method efficiently enriched and detected bioaerosols in plant-derived smoke. This method can effectively improve the sensitivity of ATP bioluminescence detection, and possesses the advantages of convenient operation and strong anti-interference ability. It also provides a foundation for the effective detection of bioaerosols mixed with interfering substances, and a reference for evaluating the sensitivity and anti-interference of LIF-based instruments.

The effectiveness of disinfection protocols in medical school osteopathic manipulative medicine labs.

In light of the COVID-19 pandemic, healthcare-associated infections have taken center stage. Healthcare has adjusted workflows to accommodate for more robust disinfecting regiments to help protect the community. This has resulted in the need for medical institutions to reevaluate the current disinfection protocols down to the student level. The osteopathic manipulative medicine (OMM) laboratory provides an optimal avenue for assessing the effectiveness of medical students' ability to clean examination tables. With OMM laboratories having a high level of interaction, adequate disinfection is important for the health and safety of students and teaching faculties. This study will evaluate the effectiveness of the current disinfection protocols in the medical school OMM labs. A cross-sectional, nonrandomized study was performed on 20 OMM examination tables utilized for osteopathic training. Tableswere chosen based on their close proximity to the podium. Close proximity was utilized as a criteria to increase the probability of utilization by students. The sampled tables were observed to ensure their use by students during class. Initial samples were collected in the morning after disinfection by Environmental Services. Terminal samples were collected after Osteopathic medical students utilized and disinfected the OMM examination tables. Samples were collected from the face-cradle and midtorso regions and analyzed utilizing adenosine triphosphate (ATP) bioluminescence assays with an AccuPoint Advanced HC Reader. This reader provides a digital readout of the quantity of light measured in relative light units (RLUs), which is directly correlated to the amount of ATP present in the sample, providing an estimated pathogen count. For statistical analysis, a Wilcoxon signed-rank test was utilized to find statistical differences in RLUs in samples after initial and terminal disinfection. The face cradle showed a 40 % increase in failure rate in samples after terminal disinfection when samples were compared after initial disinfection. A Wilcoxon signed-rank test revealed an estimated pathogen level for face cradle that was significantly higher after terminal disinfection (median, 4,295 RLUs; range, 2,269-12919 RLUs; n=20) compared to initial disinfection (median, 769 RLUs; range, 29-2,422 RLUs; n=20), z=-3.8, p=0.00008, with a large effect size, d=2.2. The midtorso region showed a 75 % increase in samples after terminal disinfection when samples were compared after initial disinfection. A Wilcoxon signed-rank test revealed that the estimated pathogen levels for midtorso were significantly higher after terminal disinfecting (median, 656 RLUs; range, 112-1,922 RLUs; n=20) compared to initial disinfecting (median, 128 RLUs; range, 1-335 RLUs; n=20), z=-3.9, p=0.00012, with a large effect size, d=1.8. This study suggests that medical students frequently failed to disinfect high-touch regions on examination tables, such as the midtorso and the face cradle. It is recommended that the current OMM lab disinfection protocol be modified to include the disinfection of high-touch regions in order to reduce the possibility of pathogen transmission. Further research should explore the effectiveness of disinfection protocols in clinical settings such as outpatient offices.

Comparison of coliform paper test and ATP bioluminescence assay for monitoring the disinfection of kitchen utensils in canteens of hebei, China

BackgroundTwo common techniques used in canteen hygiene supervision, are the coliform paper assay, which is the standard method, and the adenosine triphosphate (ATP) bioluminescence method. The coliform paper assay requires the incubation of the sample, which is time-consuming and does not provide a real-time assessment. Meanwhile, the ATP bioluminescence assay can provide real-time kitchenware cleanliness data. ObjectiveThis study aimed to compare these two methods for evaluating the sanitary condition of kitchenware and explore whether the ATP bioluminescence assay can be used as a standard method in sanitary inspection. MethodsIn this study, the cluster random sampling method was used to sample kitchenware from six canteens in the Hebei province, China. Samples were, assessed through the coliform paper test and ATP bioluminescence assay. ResultsKitchenware negative rates for the coliform paper method and the ATP test were 64.39% and 49.07%, respectively. The Escherichia coli positive detection rate grew steadily as the relative light units (RLU) value for the ATP technique increased. The kappa coefficient for the two methods was 0.549, indicating that the two methods yield relatively consistent results. ConclusionAlthough currently not considered a standard method, simply using ATP detection is advantageous for quick on-site detection in catering unit hygiene supervision.

Effectiveness of adenosine triphosphate to monitor manual cleaning and disinfection efficacy of flexible endoscopes in Hong Kong.

Adenosine triphosphate (ATP) bioluminescence assay is widely adopted in the West to allow rapid evaluation of endoscopes for bacteriologic/biologic residue, but this practice is rarely adopted in Asia. In this continuous quality improvement program, we evaluated the utility of ATP in bacteriologic surveillance on endoscope reprocessing. A total of 456 samples (304 ATP samples and 152 culture samples) of 38 flexible endoscopes were assessed after routine clinical use in a private hospital in Hong Kong. Endoscopes were assessed with an ATP system and bacterial cultures at different time points during the reprocessing. After pre-cleaning, the ATP values ranged from 228 to 65 163 relative light units (RLU) through all endoscope types. After manual cleaning, ATP values were decreased to 7-81 RLU (median, 19 RLU) for endoscope surface and 3-671 RLU (median, 12 RLU) for channel rinsate. There was a significant reduction in ATP levels between pre-cleaning and after manual cleaning. One of the 38 (2.6%) endoscopes (a duodenoscope) had an ATP value of 671 RLU from channel rinsate, which exceeded the benchmark for cleanliness of >200 RLU, and was sent back for re-cleaning. All endoscopes cultured no bacteria after high-level disinfection (HLD) by automated endoscope reprocessor (AER) and storage up to 24 h. ATP values were <200 RLU for all endoscopes after HLD and storage. Adenosine triphosphate bioluminescence assay offers a rapid, practical, and cost-effective alternative for detection of endoscope microbial residue as well as a routine monitoring tool for endoscope cleanliness in the clinical setting.

Impact of Plastic-Wrap Properties and Cleaning Intervals on the Disinfection of Elevator Buttons.

Fomite transmission is a possible route by which different pathogens spread within facilities. In hospital settings, elevator buttons are widely observed to be covered with various types of plastic wraps; however, limited information is available concerning the impact of different plastic materials on cleaning. Our study aimed to identify which plastic material is suitable for the coverage of elevator buttons and the optimal intervals for their cleaning. We tested six plastic covers, including polyethylene (PE), polymethylpentene (PMP), polyvinyl chloride (PVD), and polyvinylidene chloride (PVDC) plastic wraps; a thermoplastic polyurethane (TPU) keyboard cover; and a polyethylene terephthalate-ethylene vinyl acetate (PET-EVA) laminating film, which are plastic films. The bioburden on the elevator buttons at different time intervals was measured using an adenosine triphosphate (ATP) bioluminescence assay. Our results show that wraps made of PVDC had superior durability compared with those of PMP, PVC, and PVDC, in addition to the lowest detectable ATP levels among the six tested materials. Regarding different button locations, the highest ATP values were found in door-close buttons followed by door-open, and first-floor buttons after one- and three-hour intervals (p = 0.024 and p < 0.001, respectively). After routine disinfection, the ATP levels of buttons rapidly increased after touching and became more prominent after three hours (p < 0.05). Our results indicate that PVDC plastic wraps have adequate durability and the lowest residual bioburden when applied as covers for elevator buttons. Door-close and -open buttons were the most frequently touched sites, requiring more accurate and precise disinfection; therefore, cleaning intervals of no longer than three hours may be warranted.

Antimicrobial Effects of Gatifloxacin on Canine Periodontopathic Bacteria &amp;lt;i&amp;gt;In Vitro&amp;lt;/i&amp;gt;

The aim of this study was to identify the potential antibacterial effects of gatifloxacin on one of canine periodontal pathogens, Porphyromonas gulae. The minimum inhibitory concentrations (MIC) of gatifloxacin and its bactericidal effects were investigated. Gatifloxacin inhibited the growth of the canine periodontopathic bacteria tested in broth. An MIC of 50 nM was found to be effective in inhibiting P. gulae. On performing adenosine triphosphate bioluminescence assay, gatifloxacin was found to exhibit bactericidal effects on the tested bacteria in a concentration-dependent manner. The safety of gatifloxacin in mammalian cells was evaluated by assessing the viability of rat bone marrow mesenchymal stem (BMMS) cells treated with gatifloxacin. Almost over 80% of BMMS cells survived after a 3-day culture when treated with 100 nM of gatifloxacin. These results indicate that locally administered gatifloxacin has the potential for being used to prevent canine periodontal infection.

A multiphase intervention of novel color additive for bleach disinfectant wipes improves thoroughness of cleaning in an academic medical center

Surface disinfection is critical for preventing health care-associated infections; however, sustaining high-quality cleaning technique is challenging without constant feedback and training of staff. A novel color additive to bleach wipes, Highlight, indicates where surfaces have been wiped and fades to colorless to provide real-time visual feedback of cleaning. In a multiphase interventional study, Highlight reduced failure rates of cleaning based on fluorescent marker removal (15.0%-4.5%) and adenosine triphosphate bioluminescence assay (3.6%-2.5%).

Monitoring the Cleanliness of Reusable Surgical Instruments in Central Sterile Supply Department by Adenosine Triphosphate Method.

Cleaning is very important in reusable surgical instruments (RSI) reprocessing. The adenosine triphosphate (ATP) method is widely used to assess cleanliness, but few studies focus on using this method on RSIs. To assess the effectiveness of the ATP Bioluminescence Assay for monitoring the cleanliness of RSIs. The study was conducted in three central sterile supply departments (CSSD) from 2015 to 2020. Surgical scissors, hemostatic forceps, and other non-lumen instruments were sampled after cleaning. The surface of each instrument was swabbed in a uniform manner, including hinged joints and teeth, and the amount of ATP (amol) was calculated. A total of 871 RSIs were tested, the mean ATP lg (amol) was 2.829 ± 0.539 and the qualified rate was 80.57%. Washer-disinfector cleaning was more efficient than manual cleaning, the mean ATP lg (amol) were 2.776 ± 0.513 and 2.948 ± 0.575, respectively; the qualified rates were 84.97% and 70.59%, respectively. With the time of bare instruments expose to environment increased, the qualified rate was decreased (Ptrend = 0.044). ATP levels are stable and repeatable for continuous monitoring of the cleanliness of RSIs. It is a rapid and viable method for assessing the cleanliness of RSIs. Washer-disinfector cleaning is recommended and cleaned instruments should be placed in sterile packaging in good time. The ATP method is viable for assessing the cleanliness of RSI in CSSDs.

ATP Bioluminescence for Assessing the Efficacy of the Manual Cleaning Procedure during the Reprocessing of Reusable Surgical Instruments.

Achieving sterilization by adopting proper practices is essential to ensure that surgical instruments do not transmit microorganisms to patients. As the effectiveness of sterilization mandates effective cleaning, it is necessary to verify the success of cleaning procedures. In this study, we used the adenosine triphosphate (ATP) bioluminescence method for assessing the efficacy of the manual cleaning procedure during the reprocessing of reusable surgical instruments. The ATP bioluminescence assay was performed on 140 surgical instruments of 12 different types, both before being cleaned (baseline) and after each of the cleaning procedures (i.e., decontamination, manual washing, drying, and visual inspection). For each instrument, two swabs were used as follows: one to sample the entire surface (test point 1) and the other to sample the most difficult part of the surface to clean (test point 2). Overall, for each type of instrument, there was a decrease in contamination ranging from 99.6 to >99.9% (log reduction from 2.40 to 3.76). Thus, in order to standardize the assessment of cleanliness, it may be useful to introduce the bioluminescence method into the daily routine or, at least, at regular time intervals as a complementary check combined with visual inspection. This would allow real-time verification of the achievement of an adequate level of cleanliness.

Perioral Aerosol Sequestration Suction Device Effectively Reduces Biological Cross-Contamination in Dental Procedures.

Objective  The infection risk during dental procedures is a common concern for dental professionals which has increased due to coronavirus (severe acute respiratory syndrome coronavirus 2) pandemic. The development of devices to specifically mitigate cross-contamination by droplet/splatter is crucial to stop infection transmission. The objective of this study is to assess the effectiveness of a perioral suction device (Oral BioFilter, OBF) to reduce biological contamination spread during dental procedures. Materials and Methods  Forty patients were randomized 1:1 to a standard professional dental hygiene treatment with OBF and without. Adenosine triphosphate (ATP) bioluminescence assay was used to evaluate the spread of potential contaminants. The total number of relative light units (RLU) from key dental operatory locations: operator’s face-shield, back of the surgical operator’s-gloves, patient’s safety-goggles, and instrumental table were measured. Percentage contamination reductions between control and OBF were compared. Statistical Analysis  Primary outcome, total RLU, was analyzed by comparing the means of logged data, using a two-sided two-sample t -test. Secondary outcomes as RLU of logged data for the different locations were analyzed in the same way. Proportion of patients from whom different locations reported events (clean, acceptable, and failure) were analyzed by using Fisher’s exact test. Results  For the whole dental environment, RLUs reduction (<150 units) achieved with OBF was 98.4% (97.4–99%). By dental operatory location the reduction in RLUs was from 99.6%, on the operator face-shield, to 83% on instrumental table. The control group reported a very high percentage of failures, (>300) being 100% on the surfaces closer to the patient’s mouth and decreasing to 70% on instrumental table. In contrast, the higher failure percentage in the OBF group was found on the patient’s goggles (40%), while the operator face-shield showed an absence of contamination. Conclusion  OBF device has shown efficient reduction of biological aerosol cross-contamination during dental procedures as proved by ATP-bioluminescence assay. Nevertheless, for maximum safety, its use must be combined with standard protective gear such as goggles, face shield, and surgical gloves.

NeoCLEAN: a multimodal strategy to enhance environmental cleaning in a resource-limited neonatal unit

BackgroundContamination of the hospital environment contributes to neonatal bacterial colonization and infection. Cleaning of hospital surfaces and equipment is seldom audited in resource-limited settings.MethodsA quasi-experimental study was conducted to assess the impact of a multimodal cleaning intervention for surfaces and equipment in a 30-bed neonatal ward. The intervention included cleaning audits with feedback, cleaning checklists, in-room cleaning wipes and training of staff and mothers in cleaning methods. Cleaning adequacy was evaluated for 100 items (58 surfaces, 42 equipment) using quantitative bacterial surface cultures, adenosine triphosphate bioluminescence assays and fluorescent ultraviolet markers, performed at baseline (P1, October 2019), early intervention (P2, November 2019) and late intervention (P3, February 2020).ResultsEnvironmental swabs (55/300; 18.3%) yielded growth of 78 potential neonatal pathogens with Enterococci, S. marcescens, K. pneumoniae, S. aureus and A. baumannii predominating. Highest aerobic colony counts were noted from moist surfaces such as sinks, milk kitchen surfaces, humidifiers and suction tubing. The proportion of surfaces and equipment exhibiting no bacterial growth increased between phases (P1 = 49%, P2 = 66%, P3 = 69%; p = 0.007). The proportion of surfaces and equipment meeting the ATP “cleanliness” threshold (< 200 relative light units) increased over time (P1 = 40%, P2 = 54%, P3 = 65%; p = 0.002), as did the UV marker removal rate (P1 = 23%, P2 = 71%, P3 = 74%; p < 0.001).ConclusionRoutine environmental cleaning of this neonatal ward was sub-optimal at baseline but improved significantly following a multimodal cleaning intervention. Involving mothers and nursing staff was key to achieving improved environmental and equipment cleaning in this resource-limited neonatal unit.

Comparative study of rapid ATP bioluminescence assay and conventional plate count method for development of rapid disinfecting activity test.

Antimicrobial activity is tested when developing disinfectants, pharmaceutical products, cosmetics, and many other consumer products. However, the plate count method, the conventional way to count the number of microorganisms, needs several days of culture. Consequently, a means of rapid microbial detection is strongly desired to replace this method. We have already developed a rapid and sensitive microbial adenosine triphosphate (ATP) detection system utilizing ATP bioluminescence, which can quantify microbial ATP within 1 h. To apply this technique to antibacterial activity tests, the ATP method should be proved equal or superior to the conventional method. In this study, we conducted disinfectant activity tests comparing the ATP method and the plate count method, using polyhexamethylene biguanide (PHMB) in different concentrations (0-10 ppm) as a model disinfectant against Staphylococcus aureus and Aspergillus brasiliensis. We found that the log reduction of intracellular ATP had a positive correlation with the log reduction of the plate count. Moreover, the ATP method was able to distinguish different conditions of injured microbial cells that were observed using scanning electron microscopy, whereas colony counting detects only culturable cells. The ATP method is thus a rapid and useful alternative to the conventional method in the field of antimicrobial activity testing.

Evaluation of different monitoring methods of surface cleanliness in operating rooms.

to evaluate different monitoring methods for detecting the presence of organic or biological matter before and after the cleaning and disinfection processes of the operating room. this is a cross-sectional study based on visual inspection, adenosine triphosphate levels and microbiological culture for the assessment of cleaning and disinfection. 93.3% of the surfaces inspected visually for this study purpose were considered clean, even when high levels of adenosine triphosphate and microbiological analysis detected presence of microorganisms relevant to biofilm formation. the cleaning and disinfection processes reduced the microbial load and organic matter of the inspected surfaces, demonstrated by the values obtained by the adenosine triphosphate bioluminescence assay and microbiological analysis, but the visual inspection as a unique tool to assess the surfaces' cleanliness may give a false impression of clean environment.

Adenosine triphosphate (ATP) bioluminescence assay for hygiene control monitoring at children's foodservice facilities in Anyang area

Adenosine triphosphate (ATP) bioluminescence assay for hygiene control monitoring at children's foodservice facilities in Anyang area

Development of a size-selective sampler combined with an adenosine triphosphate bioluminescence assay for the rapid measurement of bioaerosols

In this study, a size-selective bioaerosol sampler was built and combined with adenosine triphosphate (ATP) bioluminescence assay for measuring the bioaerosol concentration more rapidly and easily. The ATP bioaerosol sampler consisted of a respirable cyclone, an impactor to collect bioaerosols onto the head of a swab used for ATP bioluminescence assay, a swab holder, and a sampling pump. The collection efficiency of the impactor was tested using aerosolized sodium chloride particles and then the particle diameter corresponding to the collection efficiency of 50% (cut-off diameter) was evaluated. The experimental cut-off diameter was 0.44 μm. The correlations between ATP bioluminescence (relative light unit; RLU) from commercially available swabs (UltraSnap and SuperSnap, Hygiena, LLC, U.S.A.) and colony forming unit (CFU) were examined using Escherichia coli (E. coli) suspension and then the conversion equations from RLU to CFU were obtained. From the correlation results, the R2 values of UltraSnap and SuperSnap were 0.53 and 0.81, respectively. The conversion equations were the linear function and the slopes of UltraSnap and SuperSnap were 633.6 and 277.78, respectively. In the lab and field tests, the ATP bioaerosol sampler and a conventional Andersen impactor were tested and the results were compared. In the lab tests, concentrations of aerosolized E. coli collected using the sampler were highly correlated to those from the Anderson impactor (R2 = 0.85). In the field tests, the concentrations measured using the ATP bioaerosol sampler were higher than those from the Andersen impactor due to the limitations of the colony counting method. These findings confirm the feasibility of developing a sampler for rapid measurement of bioaerosol concentrations, offering a compact device for measuring exposure to bioaerosols, and an easy-to-use methodological concept for efficient air quality management.

Optimization of a Portable Adenosine Triphosphate Bioluminescence Assay Coupled with a Receiver Operating Characteristic Model to Assess Bioaerosol Concentrations on Site.

Rapid monitoring of the microbial content in indoor air is an important issue. In this study, we develop a method for applying a Coriolis sampler coupled with a portable ATP luminometer for characterization of the collection efficiency of bioaerosol samplers and then test this approach in field applications. The biological collection efficiencies of the Coriolis sampler and a BioSampler for collecting four different types of bioaerosols, including Escherichia coli, Staphylococcus aureus, Candida famata and endospores of Bacillus subtilis, were compared in a chamber study. The results showed that the ATP assay may indicate the four microbes’ viability, and that their defined viabilities were positively correlated with their culturability. In addition, the optimal sampling conditions of the Coriolis sampler were a 200 L/min flow rate and a sampling time of 30 min. Under these conditions, there was no significant difference in sampling performance between the BioSampler and Coriolis sampler. In field applications, the best ATP benchmark that corresponded to culturable levels of < 500 CFU/m3 was 287 RLUs (sensitivity: 100%; specificity: 80%) for bacteria and 370 RLUs (sensitivity: 79%; specificity: 82%) for fungi according to receiver operating characteristic curve analysis. Consequently, an ATP criterion is recommended for indicating whether the corresponding airborne culturable concentrations of microbes meet those of published guidelines.

An Original Use of a Bioluminescence Assay to Test the In Vitro Efficacy of Polihexanide in the Eradication of Acanthamoeba Cysts.

Acanthamoeba keratitis is a rare ocular disease caused by Acanthamoeba spp. The current Acanthamoeba keratitis treatments consist of unlicensed drugs, most commonly polihexanide (PHMB), a biguanide derivative, either as monotherapy or combined with a diamidine. The main purpose of this study was to develop an in vitro bioluminescence assay able to differentiate the antiamoebic activity of PHMB concentrations (0.02%, 0.04%, 0.06%, and 0.08%). Another objective of this study was to evaluate the antiamoebic activity of equal PHMB concentrations at different molecular weights (MWs). Adenosine triphosphate (ATP) bioluminescence assay applicability was established by a linear correlation between amoebae number and relative light unit emitted from cysts. The protocol consisted in a series of sequential tests, the first of which compared relative light unit emission and the hemocytometric method after cysts exposure to the different PHMB concentrations. In this assay, dilutions of the initial PHMB concentrations were used as working solutions. Usually, only 5% or less of the instilled dose into the eye is distributed through the cornea; thus, the antiamoebic activity of initial PHMB concentrations 1/10 and 1/100 diluted can reasonably be considered as representative of their undiluted dose administered in vivo. There was no significant difference between the 2 methods. The ATP bioluminescence assay ranked the antiamoebic activity of the working PHMB solutions and showed that the viability of the cysts was equally reduced at fixed PHMB concentration in a wide range of molecular weight. The ATP bioluminescence assay showed to be a simple and rapid way for characterizing the in vitro antiamoebic activity of working PHMB solutions at different concentrations.

Implementation of human factors engineering approach to improve environmental cleaning and disinfection in a medical center

BackgroundInadequate hospital cleaning may contribute to cross-transmission of pathogens. It is important to implement effective cleaning for the safe hospital environment. We conducted a three-phase study using human factors engineering (HFE) approach to enhance environmental cleanliness.MethodsThis study was conducted using a prospective interventional trial, and 28 (33.3%) of 84 wards in a medical center were sampled. The three-phases included pre-intervention analysis (Phase 1), implementing interventions by HFE principles (Phase 2), and programmatic analysis (Phase 3). The evaluations of terminal cleaning and disinfection were performed using the fluorescent marker, the adenosine triphosphate bioluminescence assay, and the aerobic colony count method simultaneously in all phases. Effective terminal cleaning and disinfection was qualified with the aggregate outcome of the same 10 high-touch surfaces per room. A score for each high-touch surface was recorded, with 0 denoting a fail and 10 denoting a pass by the benchmark of the evaluation method, and the total terminal cleaning and disinfection score (TCD score) was a score out of 100.ResultsIn each phase, 840 high-touch surfaces were collected from 84 rooms after terminal cleaning and disinfection. After the interventions, the TCD score by the three evaluation methods all showed significant improved. The carriage incidence of multidrug-resistant organism (MDRO) decreased significantly from 4.1 per 1000 patient-days to 3.6 per 1000 patient-days (P = .03).ConclusionThe HFE approach can improve the thoroughness and the effectiveness of terminal cleaning and disinfection, and resulted in a reduction of patient carriage of MDRO at hospitals. Larger studies are necessary to establish whether such efforts of cleanliness can reduce the incidence of healthcare-associated infection.