Swab Types Research Articles

Stability of milk and gliadin on swabs during 7 days under different storage conditions

Food industries rely on swabbing to control allergen and gluten occurrences in their manufacturing plant. However, collecting allergens from a surface with a swab and further analysis can be affected by numerous aspects, like the operator, the allergen, the swab fabric, the ELISA kit, and the procedure. In addition, food companies often send swabs to external laboratories, but there are no available data to describe the effect of time and temperature on the allergen or gluten stability on the swabs. This study presents the stability of milk and gliadin collected from a stainless-steel surface using different swab types (cotton, Dacron, rayon, polyester, and polyurethane). The protein concentrations were tested on days 0, 1, 2, 3, and 7 by an ELISA technique to follow the protein concentration over time. The swabs with gliadin were stored at 37 °C for 7 days to mimic poor storage conditions. The swabs used to collect milk were stored at 4 and 37 °C. The experiments indicated that, except for two cases, there was no difference in gliadin concentrations between day 1 and the other days; the same observation was made for milk. However, the swab types were not equivalent and some led to false-negative results. Validation of those observations was undertaken at a commercial laboratory. To reduce the risk of false-negatives and the effect of factors influencing the result (operator, swab, procedure, and allergen), it is recommended to swab an area in triplicate.

350 Effects of swab type on detection of PEDV from feed manufacturing surfaces

Abstract As pathogens become more prevalent within the swine industry, the demand for methods to monitor and detect them has increased. Using environmental swabbing to detect pathogens in the feed supply chain may allow for a greater likelihood of detection than product sampling. The objective of this experiment was to identify the swab that detects porcine epidemic diarrhea virus (PEDV) from feed manufacturing surfaces at the dose most similar to that included in an ingredient. The experiment was arranged as a 2×2×4 factorial with two doses of PEDV (low: 10^3 or high: 10^5 TCID50), two surface types (stainless steel or polyethylene tote), and four swab types (1: sponge-tip swab packaged with neutralizing buffer; 2: Dacron-tip swab packaged in Dey-Engley neutralizing broth; 3: dry dust-mop; or 4: cotton gauze soaked in phosphate-buffered saline). Soybean meal (SBM) was inoculated with levels of PEDV and placed onto stainless steel for 15 min, then the polyethylene tote. The SBM was removed, surfaces were swabbed with one of four types. Samples of inoculum, SBM, and swabs were analyzed for PEDV via qRT-PCR with three replicates per treatment. Data were analyzed via the GLIMMIX procedure of SAS. There was a dose×surface type×swab type interaction (P < 0.0001; SEM=0.967; Table 1). In stock virus and SBM, increased dose resulted in lower (P < 0.05) detectable PEDV. However, no virus was detected in sponge-tip swabs used on stainless steel surfaces. Dacron-tip and cotton gauze swabs yielded the most detectable PEDV from surfaces, but was still 1.2 to 5.1 Cycle threshold (Ct) higher than SBM. Detectable PEDV in SBM was approximately 11 Ct higher than in stock virus. In summary, environmental swabbing can easily detect PEDV, but at higher Ct than product samples. Of the swabs tested, Dacron-tip and cotton gauze are superior for PEDV environmental analysis than dry mops. Sponge-tip swabs should not be used for environmental monitoring of PEDV.

Collection and direct amplification methods using the GlobalFiler™ kit for DNA recovered from common pipe bomb substrates

When analyzing DNA from exploded pipe bombs, quantities are often in trace amounts, making DNA typing extremely difficult. Amplifying minute amounts of DNA can cause stochastic effects resulting in partial or uninterpretable profiles. Therefore, the initial DNA collection from “touch” evidence must be optimized to maximize the amount of DNA available for analysis.This proof-of-concept study evaluated two different swab types with two direct amplification strategies to identify the most effective method for recovering DNA from common pipe bomb substrates. PVC and steel pipes, electrical tape, and copper wire spiked with epithelial cells were swabbed with cotton or microFLOQ® Direct Swabs and amplified directly or via a pre-treatment prior to STR amplification.Not only was the microFLOQ® Direct Swab protocol the quickest method with the least risk of contamination, but in combination with direct amplification, the microFLOQ® Direct Swabs also generated the most complete STR profiles.

Influence of swabbing solution and swab type on DNA recovery from rigid environmental surfaces

Determination of the metagenome has become an important component of forensic identification, which requires efficient environmental sampling techniques. Therefore, in this study, we compared the efficiency of sample collection using swabbing with cotton swabs and three types of medical swabs (S7, S22, S24) along with three different solutions: phosphate-buffered saline (PBS), 1% Tween 20 + 1% glycerol in PBS (TG), and GS commercial solution (Noble Bio, Hwaseong, Republic of Korea). Combinations of the three solutions with the three types of swabs were tested at different volumes (cotton swab, S7: 0, 30, 50, 70 μL; S22, S24: 0, 70, 100, 130 μL). Escherichia coli and Staphylococcus aureus were selected as representative environmental microbial samples, and the number of colony-forming units (CFUs), DNA concentration, and DNA copy numbers were compared across groups. The sampling process had a clear effect on the efficiency of extraction, which allowed for determination of a more efficient sample sampling method. In particular, cotton swabs showed 2–10-fold greater CFUs of both species than the medical swabs, and resulted in significantly greater amounts of extracted DNA. TG was found to be the most efficient solution for bacterial DNA extraction, with higher CFUs and DNA obtained than with the other three solutions at all volumes tested. This study highlights the need for a standardized sampling method that can be applied to all environmental samples, especially for microbial quantification, and provides valuable reference data for the efficient collection of environmental samples for metagenomic analyses in microbial-based forensic assessments.

A comparison of flocked nylon swabs and non-flocked rayon swabs for detection of respiratory bacteria in nasopharyngeal carriage in Australian Indigenous children

This study compared flocked (nylon) swabs and (non-flocked) rayon swabs for the detection of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis in nasopharyngeal samples from 20 enrolled Indigenous children under the age of 6 years living in remote Australian Aboriginal communities, and determined which swab the child or parent perceived to be more comfortable. There was no evidence of a significant difference between flocked and rayon swabs in the recovery of common respiratory bacteria. Rayon swabs detected presence of S. pneumoniae (90% cf. 74%, p = 0.375), H. influenzae (79% cf. 74%, p = 1.00) and M. catarrhalis (79% cf. 74%, p = 1.00) at higher rates than the flocked swabs. Analysis of semi-quantitative growth scores also showed no significant differences in either the ranked distributions or medians. Rayon swabs median semi-quantitative growth scores were higher for S. pneumoniae (4 [IQR 1–5] cf. 3 [IQR 0–6], p = 0.699), and H. influenzae (2 [IQR1–5] cf. 1 [IQR0–5], p = 0.946). Sixty percent of participants preferred samples to be taken with flocked swabs. This study demonstrates that microbiological outcomes are not compromised when using flocked or rayon swabs in respiratory bacterial carriage studies in this population. Therefore, cost, methodological consistency across studies, and participant preference can be considered when choosing swab type.

Visualising latent DNA on swabs

Collection for touch DNA either at scenes or on items submitted to a forensic laboratory is based on assumptions as to where a person made direct contact. In many instances a swab may be applied to an area where no contact has been made. Many swabs may therefore be submitted for DNA profiling on which no DNA is present, resulting in the loss of both time and resources by analysing such swabs. This study has developed a simple, fast, DNA-staining and fluorescence microscopy-based screening method for swabs to indicate if there is any DNA from which to generate a profile.Ten different types of swabs were tested covering the major types used (foam, cotton and nylon). Each swab was treated by: no addition of dye or DNA, addition of dye only, addition of known DNA and addition of dye and DNA. The stain used was Diamond™ Nucleic Acid Dye (DD) and fluorescence microscopy was achieved with a digital microscope equipped with a blue LED light source (480nm) for excitation and an emission filter of 510nm. Two types of samples were tested, either buccal swabs or swabs collected from areas touched by volunteers and all analyses were performed in triplicate. The samples were collected and retained at room temperature with time intervals of 0 day, 7 days, 14 days, 21 days, and 28 days before detection using DD staining and fluorescence microscopy.Seven of the swab types used were found to be unsuitable due to the lack of any difference in the fluorescence detected when no DNA, or only the dye, or a combination of DNA and dye were added. Three swab types (black cotton swab, Ultrafine dental applicator, and Cylinder dental applicator) were found to be much more effective for collection of DNA. Further, stained cellular material retained its fluorescence for up to 4 weeks and swabs containing cellular material that had been stored for four weeks could be stained and visualised. Additionally, DD did not affect DNA profiling.This screening method has the potential to be a routine step in a forensic laboratory to save costs of processing samples where swabs are devoid of any DNA. This technique is rapid, easy, cheap, non-destructive and safe.

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.

Recovery of cytomegalovirus DNA from newborn saliva samples by different methods

BackgroundPolymerase chain reaction (PCR) testing of saliva swabs has been shown to be an attractive method to screen for congenital cytomegalovirus (CMV) infection. However, few data are available regarding the impact of pre-analytic methods on CMV DNA recovery from saliva samples under various conditions. ObjectivesThe purpose of this study was to evaluate the impact of various transport media and transport conditions on the recovery of CMV DNA from spiked and clinical saliva samples from newborns using PCR testing. Study designNegative control saliva samples were spiked with known concentrations of World Health Organization CMV standards. Collection was simulated using filter paper and different types of swabs which were stored either dry or in various transport media at specified temperatures. Specimens were tested by quantitative PCR at multiple time points. Results were compared with samples taken from newborns infected with CMV using the same methods. ResultsNucleic acid stabilization media demonstrated superior CMV stability for up to 3 weeks. Also observed was a reduction in the quantity of spiked CMV DNA over time in swab samples stored at room temperature without media or in conventional universal transport media. Swab samples from newborns infected with CMV did not demonstrate loss of CMV DNA after a week of room temperature storage in nucleic acid stabilization media or conventional universal transport media. ConclusionsAlthough nucleic acid preservation media appear to enhance CMV DNA recovery from spiked control samples over prolonged transport times and diverse conditions, this differential yield appears be to less significant for actual clinical samples collected from infected newborns. Further evaluation of pre-analytic conditions using actual clinical samples is warranted.

Prevalence of Methicillin-resistant Staphylococcus aureus in the Surgical Wards of the Port-of-Spain General Hospital, Trinidad and Tobago

Objective: Methicillin-resistant Staphylococcus aureus (MRSA) is associated with soft tissue infections in surgical patients. In severe cases, it may result in pneumonia, septicaemia and osteomyelitis. Limited data are available with regard to its prevalence and associations in the Caribbean. This study aimed to assess the prevalence of MRSA in patients hospitalized in the surgical wards of the Port-of-Spain General Hospital (POSGH), Trinidad and Tobago, and determine associated risk factors. Methods: Over the period of April 1 to August 1, 2013, all patients from the surgical wards of the POSGH who had had wound swabs taken were identified. Demographic data included duration of hospital stay, surgical and medical history, antibiotic use and type of wound swab. Microbiological reports were then retrieved and analyses done. Results: A total of 153 patients had wound swabs taken. There were 38 patients (24%) infected with Staphylococcus aureus, with 15 (39.5%) growing MRSA. Increased susceptibility to MRSA was associated with age, gender, ethnicity, duration of hospital stay, co-morbidities, previous antibiotic use, previous surgery and the type of wound (p &lt; 0.05). Conclusion: The prevalence of MRSA in the surgical wards of the POSGH was 39.5% of Staphylococcus aureus isolates. Risk factors included the age range of 60–69 years, patients with co-morbidities, hospital stays of longer than one week, previous surgery and prior use of antibiotics. We recommend more awareness of this problem in the practice of Caribbean medicine to improve infection rates.

Influenza A virus recovery, diversity, and intercontinental exchange: A multi-year assessment of wild bird sampling at Izembek National Wildlife Refuge, Alaska.

Western Alaska is a potential point-of-entry for foreign-origin influenza A viruses (IAVs) into North America via migratory birds. We sampled waterfowl and gulls for IAVs at Izembek National Wildlife Refuge (NWR) in western Alaska, USA, during late summer and autumn months of 2011–2015, to evaluate the abundance and diversity of viruses at this site. We collected 4842 samples across five years from 25 species of wild birds resulting in the recovery, isolation, and sequencing of 172 IAVs. With the intent of optimizing sampling efficiencies, we used information derived from this multi-year effort to: 1) evaluate from which species we consistently recover viruses, 2) describe viral subtypes of isolates by host species and year, 3) characterize viral gene segment sequence diversity with respect to host species, and assess potential differences in the viral lineages among the host groups, and 4) examine how evidence of intercontinental exchange of IAVs relates to host species. We consistently recovered viruses from dabbling ducks (Anas spp.), emperor geese (Chen canagica) and glaucous-winged gulls (Larus glaucescens). There was little evidence for differences in viral subtypes and diversity from different waterfowl hosts, however subtypes and viral diversity varied between waterfowl host groups and glaucous-winged gulls. Furthermore, higher proportions of viral sequences from northern pintails (Anas acuta), emperor geese and glaucous-winged gulls were grouped in phylogenetic clades that included IAV sequences originating from wild birds sampled in Asia as compared to non-pintail dabbling ducks, a difference that may be related to intercontinental migratory tendencies of host species. Our summary of research and surveillance efforts at Izembek NWR will assist in future prioritization of which hosts to sample and swab types to collect in Alaska and elsewhere in order to maximize isolate recovery, subtype and sequence diversity for resultant viruses, and detection of evidence for intercontinental viral exchange.

Sperm cell purification from mock forensic swabs using SOMAmer™ affinity reagents

We have demonstrated a proof of concept with affinity-based purification of sperm cells from mock forensic samples using SOMAmer™ reagents, DNA-based affinity reagents developed by SomaLogic, Inc. SOMAmer reagents were selected in vitro using whole-cell SELEX to bind specifically with intact, detergent-treated sperm cells. Successful separation of sperm from epithelial cells and their debris was demonstrated using buccal swabs with added semen. Primarily male DNA profiles were generated from sperm cells eluted from the types of cotton swabs typically used for rape kit evidence collection. The quality of sperm DNA isolated from samples purified using SOMAmers is comparable to existing commercially available differential extraction-based methods at higher sperm concentrations. This purification method is simple, offers relatively rapid (<2hr) sperm purification, and can potentially be automated using robotic workstations. This work serves as proof of concept that demonstrates the first use of SOMAmer reagents as affinity ligands to bind sperm cells. With further development, this technique can potentially be used for high-throughput sexual assault forensic casework.

Assessment of a swab collection method without virus transport medium for PCR diagnosis of coxsackievirus infections

Classically, detection of human enterovirus (EV) infections is based on virus isolation in tissue culture, proper sample collection and handling that optimizes virus viability. Samples are collected in virus transport medium (VTM) to ensure virus stability. High sensitivity and rapid results have made polymerase chain reaction (PCR) analysis increasingly popular for routine diagnosis. The PCR method enables simple sample collection and storage for EV diagnostics, which may eventually allow self-sampling at home.Our aim was to test a modification of the conventional clinical swab sample collection method for molecular diagnosis of EV infection. We compared swabs (cotton or synthetic) without VTM and the classical standard synthetic swabs with VTM. Effects of storage temperature (+4 °C or −80 °C) and duration were studied. EV-RNA could be detected by reverse transcriptase and nested PCR in both swab types without VTM. Differences depended on the storage duration and temperature. Optimum conditions were immediate processing or storage at −80 °C. Storage without VTM at +4 °C for longer periods is not advisable. We conclude that swabs without VTM can be considered for clinical EV-diagnostics based on PCR, and ultimately for epidemiological sample collection.

Medical-grade buccal swabs versus drugstore cotton swabs: No difference in DNA yield

We tested three types of medical-grade buccal swabs against standard cotton swabs for differences in DNA yield. A panel of swab types – one drugstore (Q-tips®) and three medical-grade – was used for buccal cell collection from three different individuals. DNA was extracted from all swabs using a QIAcube robot; quantitation values were measured by an Alu-based qPCR assay; and differences were compared through a 2-way ANOVA. Our results demonstrate that cotton swabs recover as much DNA as medical-grade swabs, but at a tremendously lower cost. Cotton swabs also display the greatest consistency of DNA yield, as indicated by the lowest coefficient of variation among the four tested swab types. These findings suggest that the use of standard cotton swabs for buccal cell collection offers not only a significant cost savings, but a more consistent method compared to the use of medical-grade swabs.

A simplified field protocol for genetic sampling of birds using buccal swabs

ABSTRACT DNA sampling is an essential prerequisite for conducting population genetic studies. For many years, blood sampling has been the preferred method for obtaining DNA in birds because of their nucleated red blood cells. Nonetheless, use of buccal swabs has been gaining favor because they are less invasive yet still yield adequate amounts of DNA for amplifying mitochondrial and nuclear markers; however, buccal swab protocols often include steps (e.g., extended air-drying and storage under frozen conditions) not easily adapted to field settings. Furthermore, commercial extraction kits and swabs for buccal sampling can be expensive for large population studies. We therefore developed an efficient, cost-effective, and field-friendly protocol for sampling wild birds after comparing DNA yield among 3 inexpensive buccal swab types (2 with foam tips and 1 with a cotton tip). Extraction and amplification success was high (100% and 97.2% respectively) using inexpensive generic swabs. We found foam-tipped swab...

Accuracy and Discomfort of Different Types of Intranasal Specimen Collection Methods for Molecular Influenza Testing in Emergency Department Patients

While development is under way of accurate, point-of-care molecular tests for influenza infection, the optimal specimen type for molecular tests remains unclear. Compared with standard nasopharyngeal swab specimens, less invasive nasal swab and midturbinate swab specimens may cause less patient discomfort and be more suitable for routine emergency department (ED) testing, although possibly at the expense of diagnostic accuracy. We compare both the accuracy of a polymerase chain reaction molecular influenza test and discomfort between these 3 intranasal specimen types. A convenience sample of adult and pediatric patients with influenza-like illness and presenting to 2 Northern California EDs and 2 EDs in Santiago, Chile, was prospectively enrolled during the 2015 to 2016 influenza season. Research nurses collected nasopharyngeal swab, midturbinate swab, and nasal swab specimens from each subject and assessed discomfort on a validated 6-point scale. Specimens were tested for influenza A and B by real-time polymerase chain reaction at reference laboratories. Outcome measures were comparison of test performance between nasal swab and midturbinate swab, when compared with a reference standard nasopharyngeal swab; and comparison of discomfort between all 3 specimen types. Four hundred eighty-four subjects were enrolled, and all 3 swabs were obtained for each subject; 14% were children. The prevalence of influenza (A or B) was 30.0% (95% confidence interval [CI] 26.0% to 34.8%). The sensitivity for detecting influenza was 98% (95% CI 94.25% to 99.65%) with the midturbinate swab versus 84.4% (95% CI 77.5% to 89.8%) with the nasal swab, difference 13.6% (95% CI 8.2% to 19.3%). Specificity was 98.5% (95% CI 96.6% to 99.5%) with the midturbinate swab versus 99.1% (95% CI 97.4% to 99.8%) with the nasal swab, difference -0.6% (95% CI -1.8% to 0.6%). Swab discomfort levels correlated with the depth of the swab type. Median discomfort scores for the nasal swab, midturbinate swab, and nasopharyngeal swab were 0, 1, and 3, respectively; the median differences were nasopharyngeal swab-midturbinate swab 2 (95% CI 1 to 2), nasopharyngeal swab-nasal swab 3 (95% CI 2 to 3), and midturbinate swab-nasal swab 1 (95% CI 1 to 2). Compared with the reference standard nasopharyngeal swab specimen, midturbinate swab specimens provided a significantly more comfortable sampling experience, with only a small sacrifice in sensitivity for influenza detection. Nasal swab specimens were significantly less sensitive than midturbinate swab. Our results suggest the midturbinate swab is the sampling method of choice for molecular influenza testing in ED patients.

A Mid-Turbinate Swab Appears Comparable to Nasopharyngeal Swabs for Quantitative Detection of RSV in Infants

BackgroundRespiratory Syncytial Virus (RSV) is the most common cause of bronchiolitis and pneumonia in infants and children. Diagnosis of RSV can be made by molecular detection of the virus in a swab of respiratory secretions. Nasopharyngeal (NP) swabs are the most frequent swab type validated for the detection of RSV, and are often considered the “gold standard” for quantification studies. However, NP sampling is invasive and uncomfortable. We sought to determine whether a less invasive method, a mid-turbinate (MT) swab, was comparable to NP sampling for quantification of RSV in infants.MethodsWe prospectively enrolled children < 24 months with a confirmed diagnosis of RSV and hospitalized at Primary Children’s Hospital (Salt Lake City, UT) during the 2015 – 2017 RSV seasons. Both an NP and MT swab were collected from each infant from different nostrils; subjects were randomized (1:1:1:1) as to the order of collection. After collection, parents were asked which collection method (NP vs. MT) they preferred. Viral loads were measured by real-time RT-qPCR. Correlation between the viral loads from the MT and NP swabs was examined. A mixed effect model was used to evaluate the mean (SD) viral loads.Results83 infants were enrolled and had swabs collected. Median age was 4 months [range 0–23]. 20 infants had swabs collected on multiple consecutive days. Median (Q1,Q3) duration of symptoms prior to enrollment was 5 days (4,7) Median (Q1,Q3) hospital stay length was 2 days (2,4). 1 infant was RSV negative according to the RT-qPCR assay. The mean (SD) viral loads were similar: 7.34 (1.26) and 7.09 (1.25) log10 copies/mL for 77 paired NP and MT swabs, respectively; see Figure 1 for median, range and quartiles. The correlation coefficient between the paired viral loads was high (0.82); see Figure 2 for Bland-Altman plot. Most parents (49/67 [73%]) who watched the swabbing preferred the MT to the NP swab.ConclusionMT swabs perform as well as NP swabs for the quantification of RSV in infants. The difference in mean viral load is small compared with the standard deviation. The less invasive MT swabs are preferred by parents for sampling. MT swabs have the potential to replace the NP swab as the “gold standard” for quantitative respiratory viral sampling.Disclosures A. J. Blaschke, Gilead Sciences, Inc: Investigator, Research support BioFire Diagnostics, LLC: Collaborator, I have intellectual property in BioFire Diagnostics through the University of Utah and Investigator, Licensing agreement or royalty and Research support

Direct PCR improves STR profiles from substrate of improvised explosive device

STR profiling from both pre-blast and post-blast IED evidence are generally unsuccessful due to the low-level of DNA present and high level of degradation. Previous studies have improved the number of alleles recovered by focusing on both the DNA collection process and the downstream processes of DNA extraction and amplification; however, direct PCR has never been used with touch DNA on IED evidence. In this study, we optimized a direct PCR protocol for touch DNA profiling from two IED substrates (PVC pipe and circuit board). Two swab types with various moistening agents and one type of tapelift were compared as the collection methods Different amounts of cutting from swab heads and tapes were evaluated. Two direct PCR protocols – the direct protocol and the pre-PCR protocol – were performed. As expected, different substrates required different collection methods for optimal DNA recovery and amplification. The direct protocol recovered significantly more alleles than the pre-PCR protocol (p<0.05). IED substrates collected using EO cotton swab with PBS yielded the best STR profiles. The findings of this study suggest that direct STR typing could be used for IED evidence, provided that an appropriate, optimal DNA collection method is used.

Internal validation of the RapidHIT® ID system

Traditionally, forensic DNA analysis has required highly skilled forensic geneticists in a dedicated laboratory to generate short tandem repeat (STR) profiles. STR profiles are routinely used either to associate or exclude potential donors of forensic biological evidence. The typing of forensic reference samples has become more demanding, especially with the requirement in some jurisdictions to DNA profile arrestees. The Rapid DNA (RDNA) platform, the RapidHIT® ID (IntegenX®, Pleasanton, CA), is a fully automated system capable of processing reference samples in approximately 90min with minimal human intervention. Thus, the RapidHIT ID instrument can be deployed to non-laboratory environments (e.g., booking stations) and run by trained atypical personnel such as law enforcement. In order to implement the RapidHIT ID platform, validation studies are needed to define the performance and limitations of the system. Internal validation studies were undertaken with four early-production RapidHIT ID units. Reliable and concordant STR profiles were obtained from reference buccal swabs. Throughout the study, no contamination was observed. The overall first-pass success rate with an “expert-like system” was 72%, which is comparable to another current RDNA platform commercially available. The system’s second-pass success rate (involving manual interpretation on first-pass inconclusive results) increased to 90%. Inhibitors (i.e., coffee, smoking tobacco, and chewing tobacco) did not appear to affect typing by the instrument system; however, substrate (i.e., swab type) did impact typing success. Additionally, one desirable feature not available with other Rapid systems is that in the event of a system failed run, a swab can be recovered and subsequently re-analyzed in a new sample cartridge. Therefore, rarely should additional sampling or swab consumption be necessary. The RapidHIT ID system is a robust and reliable tool capable of generating complete STR profiles within the forensic DNA typing laboratory or with proper training in decentralized environments by non-laboratory personnel.

Direct amplification of biological evidence and DVI samples using the Qiagen Investigator 24plex GO! Kit

Omitting DNA extraction and quantitation can save valuable time in criminal investigations and disaster victim identification (DVI) efforts. In this study, we applied different collection methods and a combination of direct amplification and lysis to various sample types in combination with the Qiagen Investigator 24plex GO! Kit. This “megaplex” kit was designed for direct PCR of DNA references, and validated with Investigator STRGO! lysis buffer. Preliminary experiments resulted in different approaches for each sample type. Missing person reference and/or post-mortem samples like hair roots, toothbrush bristles, muscle tissue and bone shavings could be successfully typed after a Proteinase K lysis step with 2mL of the volume as PCR input. Blood and saliva stains, touched fabrics and fingerprints on glass were tested with direct PCR after collection using tape lifts, cuttings, and various swab types. Using COPAN microFLOQ swabs is the most convenient collection method, but other methods, like tape lifts and small swab cuttings work as well.The two quality standards incorporated in the Qiagen 24plex kits are helpful for trouble shooting. This is especially important in the absence of Q-PCR data. Several samples, e.g. paper tissue cuttings and surface swabs from fingerprints, eye glasses and razors showed inhibition. The PCR may have been affected by the loss of reaction volume through absorption by the swab. Sources of inhibitors could have been the swab or tissue substrate, or the items, e.g. make-up on eye glasses.

Validation of commercial luminometry swabs for total bacteria and coliform counts in colostrum-feeding equipment

A sufficient quantity and quality of colostrum must be fed quickly to the newborn calf while minimizing bacterial contamination. Adenosine triphosphate bioluminescence swabs offer a potential rapid on-farm alternative to assess bacterial contamination of colostrum. The objective of this study was to validate the Hygiena (Camarillo, CA) AquaSnap Total (AS), SuperSnap (SS), PRO-Clean (PC), and MicroSnap Coliform (MS) swabs as well as visual hygiene assessment for detection of elevated bacterial counts in or on colostrum-feeding equipment. From April to October 2016, 18 esophageal tube feeders, 49 nipple bottles, and 6 pails from 52 dairy farms in Ontario were evaluated for cleanliness. Following visual hygiene assessment, sterile physiological saline (15 mL) was poured into each piece of equipment, mixed for 2 min to ensure total surface coverage, and poured into a sterile collection container through the feeding end. The fluid was split into equal aliquots, with one being evaluated by conventional culture and the other evaluated using the luminometry swabs. Nonparametric receiver operator curves were used to compare the test performance of the luminescence reading (relative light units; RLU) from each type of swab to conventional bacterial culture. The area under the curve comparing the AS swab to total bacterial count (cut point >100,000 cfu/mL) was 0.89, and using a cut point of 631 RLU correctly classified 84% of samples with a sensitivity of 88% and a specificity of 77%. The area under the curve comparing the MS swab to total coliform count (cut point >10,000 cfu/mL) was 0.85, and using a cut point of 44 RLU correctly classified 89% of samples with a sensitivity of 83% and a specificity of 90%. Visual hygiene assessment, PC and SS swabs were not reliable indicators for feeding equipment cleanliness. The results suggest that the AS and MS swabs can be used as an alternative to traditional laboratory bacterial counts to evaluate cleanliness of colostrum-feeding equipment.