Foam Swabs Research Articles

Zwitterionic hydrogel coated superhydrophilic hierarchical antifouling floater enables unimpeded interfacial steam generation and multi-contamination resistance in complex conditions

• A zwitterionic hydrogel coated evaporator is developed for solar steam generation. • The superhydrophilic surfaces and channels guarantee unimpeded water supply. • The evaporator possesses multi-contamination resistance to salt, oil, and biofouling. Continuous water pumping and steam generation are key factors in long-term solar-driven evaporation for fresh water production. However, current solar desalination devices easily get contaminated by salt accumulation, oil spill or marine fouling in real-world applications, causing blockage, corrosion or even invalidation. Developing antifouling coatings that can protect the devices from multi-contamination is a superior option to guarantee the longevity of the devices and stable fresh water generation. Herein, a superhydrophilic hierarchical antifouling floater (SHAF) consisted of zwitterionic hydrogel coated polyurethane (PU), polystyrene (PS) foam and cotton swabs, is developed. The porous PU fabric is competent to fragment water into ultra-fine droplets, increasing the vapor pressure and promoting the evaporation process. The zwitterionic coating can bind water molecules to form a hydration layer, thus leading to stable water transport and fascinating fouling resistance. Integrated with these merits, this SHAF accelerates water evaporation rate up to ~2.2 kg m −2 h −1 with a photothermal conversion efficiency of 93.5%. It also exhibits prominent microbial resistance with 96.2% against E. coli and ~100% against diatom. Additionally, due to the hydration shield induced by the zwitterionic coating, the SHAF surface is endowed with self-cleaning property even against crude oil pollution. Therefore, the SHAF with highly efficient water evaporation and multi-contamination resistance is a potential candidate for solar-driven fresh water production from seawater or even wastewater.

Polyester nasal swabs collected in a dry tube are a robust and inexpensive, minimal self-collection kit for SARS-CoV-2 testing.

In order to identify an inexpensive yet highly stable SARS-CoV-2 collection device as an alternative to foam swabs stored in transport media, both contrived ("surrogate") CoV-positive and patient-collected spun polyester swabs stored in dry tubes were evaluated for time- and temperature-stability using qPCR. Surrogate specimens were prepared by combining multiple, residual SARS-CoV-2-positive clinical specimens and diluting to near-LOD levels in either porcine or human mucus ("matrix"), inoculating foam or polyester nasal swabs, and sealing in dry tubes. Swabs were then subjected to one of three temperature excursions: (1) 4°C for up to 72 hours; (2) 40°C for 12 hours, followed by 32°C for up to 60 hours; or (3) multiple freeze-thaw cycles (-20°C). The stability of extracted SARS-CoV-2 RNA for each condition was evaluated by qPCR. Separate usability studies for the dry polyester swab-based HealthPulse@home COVID-19 Specimen Collection Kit were later conducted in both adult and pediatric populations. Polyester swabs stored dry demonstrated equivalent performance to foam swabs for detection of low and moderate SARS-CoV-2 viral loads. Mimicking warm- and cold- climate shipment, surrogate specimens were stable following either 72 hours of a high-temperature excursion or two freeze-thaw cycles. In addition, usability studies comprised of self-collected patient specimens yielded sufficient material for molecular testing, as demonstrated by RNase P detection. Polyester nasal swabs stored in dry collection tubes offer a robust and inexpensive self-collection method for SARS-CoV-2 viral load testing, as viral RNA remains stable under conditions required for home collection and shipment to the laboratory.

Enhanced forensic DNA recovery with appropriate swabs and optimized swabbing technique

Efficient sampling with swabs is crucial for optimal forensic DNA analysis. The DNA recovery is determined by the skill of the practitioner and the compatibility between the applied swab and the surface. Here we investigate the impact of swabbing technique and swab type on the DNA yield. Thirteen different swabs from four categories (cotton, flocked nylon, small foam and large foam) provided equal DNA yields for smooth/non-absorbing surfaces. Large foam swabs gave higher DNA recovery for an absorbing wood surface. Factorial design of experiments and ANOVA was applied to study swabbing techniques for cotton swabs. Two key factors for efficient sampling were found to be 1) holding the swab with an approximate 60° angle against the surface and 2) to rotate the swab during sampling. For absorbing wood, it was beneficial to wet the swab heavily. The results of the factorial experiments were used to develop swabbing protocols for different surfaces. When ten experienced practitioners sampled according to these protocols, the DNA yield was increased for ridged plastic (around 1.25 times more DNA) and absorbing wood (2.2–6.2 times more DNA). For window glass, representing a smooth/non-absorbing surface, sampling according to the protocol gave DNA yields equivalent to applying individual sampling techniques. The protocol lowered person-to-person variation for ridged plastic. In conclusion, we have developed instructive protocols for cotton swab sampling on three types of surfaces: smooth/non-absorbing, ridged/non-absorbing and smooth/absorbing. We believe that such swabbing protocols will streamline and simplify the training of new practitioners and improve sampling efficiency for invisible DNA residues in casework.

Presence of Presumptive Shiga Toxin–Producing Escherichia coli and Salmonella on Sheep during Harvest in Honduras

ABSTRACT Shiga toxin–producing Escherichia coli (STEC) and Salmonella are foodborne pathogens commonly harbored in the gastrointestinal tract of sheep. These pathogens can be on the hide of sheep and transferred to the carcass, causing a foodborne hazard. Salmonella can also be found in the lymph nodes of sheep, creating a biological hazard during harvest and processing. Developing countries lack baseline data on the presence of these foodborne pathogens on meat products, specifically sheep meat. Therefore, the objective of this study was to evaluate the presence of STEC and Salmonella on sheep hides, preevisceration carcasses, and final carcasses and Salmonella in subiliac lymph nodes from two small Honduran harvest facilities, plants A and B. Sponge swabs from the foreshank region of hides and carcasses and subiliac lymph node samples were collected from 96 sheep (86 at plant A; 10 at plant B). Microbial detection of STEC and Salmonella was performed by using the BAX System to screen for prevalence, and suspect samples were subjected to conventional culture isolation for confirmation. Overall baseline contamination on hides were 34.4 and 10.4% present for STEC and Salmonella; however, through implementation of sanitary procedures, preevisceration and final carcass samples were significantly decreased from the hide for both pathogens (P = 0.05). Moreover, overall plant A had significantly higher rates (P = 0.05) of STEC and Salmonella at each carcass sampling site compared with plant B. After each sampling was performed, recommendations were provided to each facility on the basis of pathogen presence, performance techniques, and contamination risks. Through recommendations and implementation of hazard analysis and critical control points, good manufacturing practices, and sanitation standard operating procedures in each facility, the meat supply in Honduras will become safer and more wholesome. Therefore, the development of a baseline with continued sampling is crucial to understand the risk of foodborne pathogens to consumers in the Honduran sheep meat supply. HIGHLIGHTS

Prevalence and Characterization of Escherichia coli O157:H7 on Pork Carcasses and in Swine Colon Contents from Provincially Licensed Abattoirs in Alberta, Canada

The objective of this study was to determine the prevalence of Shiga toxin-producing Escherichia coli (STEC) O157:H7 in colon contents and on carcasses from pigs slaughtered at provincially licensed abattoirs (PLAs) in Alberta, Canada. In 2017, carcass sponge samples and colon content samples were collected from 504 healthy market hogs at 39 PLAs and analyzed for E. coli O157:H7. Carcass samples were also analyzed for E. coli and aerobic colony count (ACC). Nine (1.8%) of 504 carcass samples were confirmed positive for E. coli O157:H7. Seven (1.4%) of 504 colon content samples were confirmed positive for E. coli O157:H7. These positives were found in 5 (12.8%) of 39 PLAs from hogs originating from eight farms. The E. coli O157:H7 isolates recovered from the positive samples (n = 1 isolate per sample) were clonal, as determined by pulsed-field gel electrophoresis. Six E. coli O157:H7 isolates obtained over 8 months from one PLA that only processed hogs and sourced hogs from one farm had indistinguishable pulsed-field gel electrophoresis patterns. All 16 E. coli O157:H7 isolates harbored eae and ehxA and were of stx2a subtype, suggesting that swine can carry E. coli O157:H7 of importance to human health. All carcass sponge swabs (100%) were positive for ACC. E. coli was present in 72% of carcass swabs. Carcasses from PLAs slaughtering both beef and hogs had a numerically higher ACC mean value but not statistically different compared with the carcasses from PLAs slaughtering only swine (2,799 and 610 CFU/cm2, respectively). E. coli showed a similar trend with a mean value of 0.88 CFU/cm2 in PLAs slaughtering both species and 0.26 CFU/cm2 in PLAs slaughtering only swine (P ≤ 0.05). This study provides evidence that healthy market hogs from different producers and farms in Alberta can carry E. coli O157:H7, and some strains of the organism may be able to establish persistence on some swine farms.

Laboratory evaluation of the Sigma Transwab\xae transport system for the recovery of Candida species using the Clinical and Laboratory Standards Institute (CLSI) document M40-A2

Rising healthcare complications due to fungal infections increase the importance of efficient specimen collection and maintenance systems for correct identification and diagnosis. The CLSI M40-A2 protocol provides guidelines for laboratories assessing quality of medical transport devices, including swab transport systems (STS). This study assessed the efficiency of the Sigma Transwab® foam and flock swab in recovering and maintaining viability of different Candida spp. including C. auris, in different test conditions. Both swab types recovered and maintained viability of all Candida spp. with greater CFU at room temperature after incubation (24 and 48 h) in comparison with swabs maintained at 4 °C.

The novel use of a spray-on rubber coating to recover cellular material from the surface of bricks

Currently, forensic investigators utilise various types of swabs and tape lifts to recover cellular material from coarse surfaces identified during a criminal investigation. However, a number of challenges prevent successful recovery and therefore warrants the need for an alternative method. Plasti dip® is peel-off rubber coating that can be applied to most surfaces and may have an application in the recovery of DNA from coarse surfaces. The aim of this study was to determine the effectiveness of Plasti dip® to recover DNA from coarse brick surfaces and assess how this method compares to current techniques. Cellular material was deposited onto brick pieces in varying concentrations and recovered with either flocked, foam or rayon swabs, or Plasti dip®. Material recovered, using each technique, was extracted and quantitated for comparison of DNA yields. At low and medium cell concentrations, an observable but not statistically significant difference was observed between the swabbing methods and Plasti dip®. At high cell concentrations Plasti dip® was able to recover a significantly higher DNA concentration than all three swabbing methods. Quantitation results indicated no degradation of DNA. This is a novel approach to the collection of trace DNA from surfaces that have historically proven difficult to sample. While there is further validation required, this landmark study demonstrates the potential that spray-on rubber coatings have for casework involving rough, porous surfaces like bricks, stones or rocks.

Evaluation of Sampling Methods for Detection of Pathogens from Steel Surfaces; Contact Plates, Foam Swabs, and Flocked Swabs

Background: Contaminated healthcare surfaces can serve as reservoirs for the transmission of pathogens. Sensitive sampling methods are needed to investigate sources of pathogens for implementing effective disinfection strategies and thereby preventing environmental transmission. Conventional approaches employ swabs to sample environmental surfaces. Contact plates represent an alternative approach for sampling healthcare surfaces that does not require lab processing, though little is known about their performance. A contact plate is an agar plate that is overfilled with selective or nonselective media. It can be gently applied to the surface, then simply incubated at a temperature optimal for target organism (s), thus saving time and resources. Methods: In this study, contact plates containing trypticase soy agar with 5% sheep blood (TSAII), foam swabs, and flocked swabs were evaluated for their ability to recover 4 pathogens that persist on healthcare surfaces. Stainless-steel coupons (4 in2) were inoculated with the following pathogens (102 CFU): Acinetobacter baumannii (AB, strain type 12), carbapenemase-producing KPC+ Klebsiella pneumoniae (KP; ATCC BAA-1705); methicillin-resistant Staphylococcus aureus (MRSA; ATCC 43300); and vancomycin-resistant Enterococcus faecalis (VRE; Van A + 256). The plates were allowed to dry 1 hour. Sampling with CPs was performed in 2 ways; (1) a single contact plate was used to sample 1 stainless-steel surface and (2) a composite was collected by 3 sequential contact-plate samplings of the same stainless-steel surface. The contact plates were then incubated at 351C. Foam and flocked swabs were premoistened with phosphate-buffered saline + 0.02% polysorbate 80 (PBST) and were used to sample the stainless-steel coupons. Swabs were held for 1 hour and processed by sonication and vortexing in 5 mL of PBST, then the eluent was cultured and CFU counted. Mean percentage recoveries (%R) relative to the inoculum were calculated and compared. Results: When the %R for all 4 pathogens were pooled, the composite contact-plate sampling method yielded the highest, (P < .05) (66.0%; SD, 0.22), followed by the single contact plate method (39.7%; SD, 0.12), foam swab (32.9%; SD, 0.18), and flocked swab (20.3%; SD, 0.20). The composite contact plate method yielded the highest %R for VRE (102.1 %; SD, 0.17), and the lowest %R was observed when using flocked swabs to recover KP (6.3%; SD, 0.05). Conclusions: The contact-plate composite method may provide investigators with minimal environmental microbiology capacity an alternative method for environmental sampling and detection of organisms from surface areas (4 in 2) with low bioburden.Funding: NoneDisclosures: None

Diagnostic and treatment of nose bleeding in children with chronic hepatitis B

State of the problem: Nasal bleeding is one of the most common causes of patients seeking emergency otorhinolaryngological care, as well as the most common type of bleeding in medical practice. Frequent causes of nosebleeds are changes in the vascular wall, hemorrhagic diathesis, atherosclerosis, as well as diseases of the blood, kidneys, liver. Purpose of research: To study the clinical course and effectiveness of some methods of treatment of nosebleeds in chronic hepatitis B in children. Materials and methods: We observed 78 children aged 3 to 17 years. The method of examination included a detailed study of complaints and anamnesis of patients, endoscopic examination of the nasal cavity, radiography of the nose and paranasal sinuses. Patients were divided into 2 groups. The first group consisted of 30 patients in whom treatment was carried out by the proposed method (after detachment of the mucous membranes into the nasal passages of the patient, a standard hemostatic sponge swab soaked in solcoseryl Gel was introduced), the second group included 20 patients who received traditional treatment (effect on the bleeding area with vaseline, which was previously applied to the gauze swab). Results: Chronic hepatitis b In children retains its characteristic clinical signs, including subatrophy and dryness of the mucous membranes of the nose, nasal bleeding, adhesions of the nasal cavity, the hepatosplenomegaly and the violation of some biochemical parameters. Nosebleeds on the background of chronic hepatitis B occur with frequent relapses, which contribute to the severe course of chronic hepatitis B and can lead to an unfavorable outcome. Conclusion: Good clinical effect of selective sparing surgical technique: endoscopic submucosal detachment of the nasal septum in the region of the zone of Kisselbach, with subsequent tamponade hemostatic sponge impregnated with ointment “Solcoseryl”.

Impact of swab material on microbial surface sampling

Efficient microbial sampling from surfaces for subsequent detection and quantification is crucial in fields such as food safety and hygiene monitoring. Cotton swabs are traditionally used for sample collection, but today there are numerous swabs of alternative material and different sizes available. Recovery efficiencies of swabs for different applications have been compared in several studies. However, the results are often contradictory. We have compared 15 different swabs made of cotton (n = 5), flocked nylon (n = 3) and foam (n = 7), for sampling of Listeria monocytogenes and mengovirus on small (4 cm2) and large (100 cm2) areas of window glass, ridged plastic and absorbing wood. Molecular quantification methods (qPCR and RT-qPCR) were applied, and all sampling and sample processing were standardized. Specific swabs gave higher DNA/RNA yields than others, depending on both the surface characteristics and the collected target. The highest DNA yields were achieved by applying Selefa or Puritan cotton swabs for Listeria sampling on 4 cm2 areas of window glass and ridged plastic. Certain foam swabs (Critical swab with medium head and Macrofoam) gave the highest yields when sampling Listeria on 4 cm2 areas of wood and on 100 cm2 areas of ridged plastic and wood. Most foam swabs, and especially Sigma Virocult, were advantageous for virus sampling, regardless of surface. Nylon-flocked swabs showed poor recovery regardless of surface characteristics. The recovery varied substantially between swabs made of the same material, suggesting that a single swab may not be representative for a certain swab material.

Reliability of Self-Sampling for Accurate Assessment of Respiratory Virus Viral and Immunologic Kinetics.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic demonstrates the need for accurate and convenient approaches to diagnose and therapeutically monitor respiratory viral infections. We demonstrated that self-sampling with mid-nasal foam swabs is well-tolerated and provides quantitative viral output concordant with flocked swabs. Using longitudinal home-based self-sampling, we demonstrate that nasal cytokine levels correlate and cluster according to immune cell of origin. Periods of stable viral loads are followed by rapid elimination, which could be coupled with cytokine expansion and contraction. Nasal foam swab self-sampling at home provides a precise, mechanistic readout of respiratory virus shedding and local immune responses.

AOAC-OMA/MicroVal Harmonized Validation of Peel PlateTM EB (Enterobacteriaceae Bacteria), First Action 2018.05.

BackgroundPeel PlateTM Enterobacteriaceae Bacteria (EB) is dried selective media on a 47 mm plastic plate that produces enzyme substrate colored colonies on rehydration and incubation for 24 h and up to 48 h at 37 ± 1°C.PurposeThe method validation compared quantification of EB to reference methods ISO 21528:2017 Parts 1 and 2.MethodsMatrixes compared were whole milk, skim powdered milk, vanilla ice cream, butter, infant formulas (soy- and dairy-based), infant cereals ± probiotic, environmental sponge swab of stainless steel surface, and poultry carcass rinse with two different peptone buffers.ResultsIn inclusivity and exclusivity studies, the method detected 54 of 54 EB strains and did not detect 30 of 30 non-EB strains. In matrix studies, the claimed foods were tested at three contamination levels using paired analysis between the reference and Peel Plate EB methods. Colony-forming units per gram or mL [CFU/g (mL)] were log10 transformed for statistical analysis. The candidate method and reference method were shown to be equivalent by the performance requirement of all 95% confidence intervals on mean difference falling between −0.5 and +0.5 log10 CFU/g (mL). An international collaborative study with dried infant formula spiked with Cronobacter sakazakii at log10 CFU/g (mL) 1.05, 2.31, and 3.21 levels, produced method differences −0.16, 0.15, and 0.18 log10 CFU/g (mL) with repeatabilities (r) = 0.33, 0.20, and 0.12 log10 CFU/g (mL) and reproducibilities (R) = 0.45, 0.26, and 0.18 log10 CFU/g (mL).ConclusionsBased on these evaluations, the candidate method is considered equivalent to the reference methods at both the 24 h and 48 h incubation periods at 37 ± 1°C.HighlightsReady to use Enterobacteriaceae method equivalent to ISO-21528:2017 Parts 1 and 2; EB test colored colonies at 37°C for 24 h are equivalent at 48 h incubation; Singlet determined CFU/mL are statistically the same as duplicate average results; EB test validated for infant formula and dairy products including with probiotics; EB test for environmental surfaces and poultry carcass rinses using peptone buffers.

Toothbrushing for Dependent Neurological Patients in the Intensive Care Unit

Toothbrushing for Dependent Neurological Patients in the Intensive Care Unit

Critical evaluation of touch DNA recovery methods for forensic purposes

Over the past decade there has been a significant increase in the number of submissions of ‘touch DNA’ evidence to forensic laboratories. Previous research has indicated that analysis of these samples produces low success rates. Published research, as well as case work review by forensic practitioners, has also indicated more consideration of how to improve the evidential value of ‘touch DNA’ samples is needed. Therefore, this research aims to critically evaluate low level DNA recovery methods in order to maximise efficiency for forensic identification purposes. Typical evidential items, such as plastic handled screwdrivers, aluminium cans, drinking glasses and wooden handles, were handled in a mock-operational trial. The deposited DNA was recovered from these items using a range of swabbing materials including cotton, polyester and foam. These samples then underwent quantitative PCR analysis and were profiled using AmpFLSTR™ NGM SElect™. The DNA quantity and quality were compared and a statistically significant differences were found to be present between recovery methods with the foam swab recovering more donor alleles overall.

The Extraction and Recovery Efficiency of Pure DNA for Different Types of Swabs

The extraction and recovery efficiency of swabs used to collect evidence at crime scenes is relatively low (typically <50%) for bacterial spores and body fluids. Cell-free deoxyribonucleic acid (DNA) is an interesting alternative compared to whole cells as a source for forensic analysis, but extraction and recovery from swabs has not been tested before using pure DNA. In this study cotton, foam, nylon flocked, polyester and rayon swabs are investigated in order to collect pure DNA isolated from saliva samples. The morphology and absorption capacity of swabs is studied. Extraction and recovery efficiencies are determined and compared to the maximum theoretical efficiency. The results indicate that a substantial part of DNA is not extracted from the swab and some types of swab seem to bind effectively with DNA. The efficiency of the different types of swab never exceeds 50%. The nylon flocked 4N6FLOQSwab used for buccal sampling performs the best.

The effect of transportation and lairage on faecal shedding and carcass contamination with Escherichia coli O157 and O26 in very young calves in New Zealand.

The effect of transportation and lairage on the faecal shedding and post-slaughter contamination of carcasses with Escherichia coli O157 and O26 in young calves (4-7-day-old) was assessed in a cohort study at a regional calf-processing plant in the North Island of New Zealand, following 60 calves as cohorts from six dairy farms to slaughter. Multiple samples from each animal at pre-slaughter (recto-anal mucosal swab) and carcass at post-slaughter (sponge swab) were collected and screened using real-time PCR and culture isolation methods for the presence of E. coli O157 and O26 (Shiga toxin-producing E. coli (STEC) and non-STEC). Genotype analysis of E. coli O157 and O26 isolates provided little evidence of faecal-oral transmission of infection between calves during transportation and lairage. Increased cross-contamination of hides and carcasses with E. coli O157 and O26 between co-transported calves was confirmed at pre-hide removal and post-evisceration stages but not at pre-boning (at the end of dressing prior to chilling), indicating that good hygiene practices and application of an approved intervention effectively controlled carcass contamination. This study was the first of its kind to assess the impact of transportation and lairage on the faecal carriage and post-harvest contamination of carcasses with E. coli O157 and O26 in very young calves.

The Power of a Toothbrush

The Power of a Toothbrush

Identification of Clostridium difficile Reservoirs in The Patient Environment and Efficacy of Aerial Hydrogen Peroxide Decontamination.

OBJECTIVE To identify, using a novel enhanced method of recovery, environmental sites where spores of Clostridium difficile persist despite cleaning and hydrogen peroxide aerial decontamination. DESIGN Cohort study. SETTING Tertiary referral center teaching hospital. METHODS In total, 16 sites representing high-frequency contact or difficult-to-clean surfaces in a single-isolation room or bed area in patient bed bays were sampled before and after terminal or hydrogen peroxide disinfection using a sponge swab. In some rooms, individual sites were not present (eg, there were no en-suite rooms in the ICU). Swab contents were homogenized, concentrated by membrane-filtration, and plated onto selective media. Results of C. difficile sampling were used to focus cleaning. RESULTS Over 1 year, 2,529 sites from 146 rooms and 44 bays were sampled. Clostridium difficile was found on 131 of 572 surfaces (22.9%) before terminal cleaning, on 105 of 959 surfaces (10.6%) after terminal cleaning, and on 43 of 967 surfaces (4.4%) after hydrogen peroxide disinfection. Clostridium difficile persisted most frequently on floor corners (97 of 334; 29.0%) after disinfection. Between the first and third quarters, we observed a significant decrease in the number of positive sites (25 of 390 vs 6 of 256). However, no similar change in the number of isolates before terminal cleaning was observed. CONCLUSION Persistence of C. difficile in the clinical environment was widespread. Although feedback of results did not improve the efficacy of manual disinfection, numbers of C. difficile following hydrogen peroxide gradually declined. Infect Control Hosp Epidemiol 2017;38:1487-1492.

Comparison of skin decontamination efficacy of commercial decontamination products following exposure to VX on human skin

The decontamination efficacy of four commercially available skin decontamination products following exposure to the nerve agent VX was evaluated in vitro utilizing a diffusion cell and dermatomed human skin. The products included were Reactive Skin Decontamination Lotion (RSDL), the Swedish decontamination powder 104 (PS104), the absorbent Fuller's Earth and the aqueous solution alldecontMED. In addition, various decontamination procedures were assessed to further investigate important mechanisms involved in the specific products, e.g. decontamination removal from skin, physical removal by sponge swabbing and activation of degradation mechanisms. The efficacy of each decontamination product was evaluated 5 or 30 min after dermal application of VX (neat or diluted to 20% in water).The RSDL-lotion was superior in reducing the penetration of VX through human skin, both when exposed as neat agent and when diluted to 20% in water. Swabbing with the RSDL-sponge during 2 min revealed decreased efficacy compared to applying the RSDL-lotion directly on the skin for 30 min. Decontamination with Fuller's Earth and alldecontMED significantly reduced the penetration of neat concentration of VX through human skin. PS104-powder was insufficient for decontamination of VX at both time-points, independently of the skin contact time of PS104. The PS104-slurry (a mixture of PS104-powder and water), slightly improved the decontamination efficacy. Comparing the time-points for initiated decontamination revealed less penetrated VX for RSDL and Fuller's Earth when decontamination was initiated after 5 min compared to 30 min post-exposure, while alldecontMED displayed similar efficacy at both time-points. Decontamination by washing with water only resulted in a significant reduction of penetrated VX when washing was performed 5 min after exposure, but not when decontamination was delayed to 30 min post-exposure of neat VX.In conclusion, early initiated decontamination with the RSDL-lotion, containing both absorption and degrading properties, allowed to act on skin for 30 min was superior in preventing VX from penetrating human skin. Adding water during decontamination resulted in increased penetration of neat VX, however, water in the decontaminant removal process did not influence the decontamination efficacy. From our study on commercially available decontaminants, it is recommended that future product developments should include both strong absorbents and efficient nerve agent degrading components.

Rapid detection of Group B streptococcus directly from vaginal–rectal specimens using liquid swabs and the BD Max GBS assay

ObjectiveWe adapted the BD Max GBS assay, an automated platform for the detection of Group B streptococcus (GBS) DNA in vaginal–rectal swab specimens after LIM broth enrichment, to directly detect GBS in specimens collected using cellular foam swabs in Amies liquid medium. We compared the BD Max GBS assay performance to that of enriched culture and the BD GeneOhm StrepB assay. MethodsSeventy-two reference vaginal–rectal specimens were employed to determine the limit of GBS detection and the preferred test volume for direct detection of GBS. A total of 304 clinical specimens were then tested by the optimized BD Max GBS assay, both by direct testing and following broth enrichment. ResultsThe limit of GBS detection was 75 CFU/mL and the preferred test volume was 100 μL. Of 304 clinical specimens tested, GBS was detected in 62 specimens by enriched culture (20.4%); 61 of these yielded GBS by the BD Max GBS assay when performed directly from the liquid swab (sensitivity 98.4%). All 242 culture-negative specimens also yielded negative results by the BD Max GBS assay (specificity 100%). When this assay was performed following broth enrichment, GBS was detected in all 62 culture-positive specimens (100% sensitivity). The sensitivity and specificity of the BD GeneOhm StrepB assay was 90.3% and 99%, respectively. ConclusionsThe BD Max GBS assay is highly sensitive, requires minimal technical skill with <2 min required to set-up, and results are available in under 80 min (versus 24–48 h for culture). It is configured for ‘on demand’ testing and vaginal–rectal specimens can be rapidly screened for GBS without the need for enrichment. The results obtained in this study demonstrate that rapid GBS screening using the BD Max GBS assay at the time of delivery is a viable alternative to the current recommended screening at 35–37 weeks of gestation with pre-enrichment testing methods.