Dry Swabs and Dried Saliva as Alternative Samples for SARS-CoV-2 Detection in Remote Areas in Lao PDR.

Background: Surveillance of SARS-CoV-2 circulation is mainly based on real-time reverse transcription-polymerase chain reaction, which requires laboratory facilities and cold chain for sample transportation. This is difficult to achieve in remote rural areas of resource-limited settings. The use of dried blood spots shipped at room temperature has shown good efficiency for the detection of arboviral RNA. Using a similar approach, we conducted a study at 3 provincial hospitals in Laos to compare the detection of SARS-CoV-2 from neat and dried spot samples. Methods: Between January 2022 and March 2023, patients with respiratory symptoms were recruited. Nasopharyngeal/oropharyngeal swabs in virus transport medium (VTM), dry swabs, saliva, and dried saliva spotted on filter paper were collected. All samples were tested by SARS-CoV-2 real-time reverse transcription-polymerase chain reaction. Results: In total, 479 participants were included. The VTM samples tested positive for 288 (60.1%). High positive percent agreements were observed for dry swab (84.8%; 95% CI, 80.2%-88.8%) and saliva (89.2%; 95% CI, 85.1%-92.6%) as compared with VTM. There was a loss of sensitivity when saliva was dried on filter paper (73.6%; 95% CI, 68.1%-78.6%) as compared with saliva. SARS-CoV-2 variant (Delta or Omicron) had no significant impact on the performance of the different sample types. Conclusions: Our findings suggest that dry swabs could be a good alternative for sample collection and permit easy shipping at ambient temperature for subsequent viral SARS-CoV-2 RNA purification and molecular investigation. This is a useful tool to consider for a rapid implementation of large-scale surveillance of SARS-CoV-2 in remote areas, which could be extrapolated to other respiratory targets during routine surveillance or in the case of a novel emerging pandemic.

Intermediate Cluster Disinfection: Which Disinfection Solution Is Most Effective on Milking Liners? A Comparison of Microorganism Reduction on Liner Inner Surfaces Using Quantitative Swab Sampling Technique.

During machine milking, pathogenic microorganisms can be transmitted from cow to cow through liners. Therefore, in Germany, a spray method for the intermediate disinfection of the milking cluster is often used for prevention. This method of cluster disinfection is easy to perform, requires little time and no extra materials, and the disinfection solution is safe from outside contamination in the spray bottle. Since no data on a systematic efficacy trial are available, the aim of this study was to determine the microbial reduction effect of intermediate disinfection. Therefore, laboratory and field trials were conducted. In both trials, two sprays of 0.85 mL per burst of different disinfectant solutions were sprayed into the contaminated liners. For sampling, a quantitative swabbing method using a modified wet-dry swab (WDS) technique based on DIN 10113-1: 1997-07 was applied. Thus, the effectiveness of disinfectants based on Peracetic Acid, Hydrogen Peroxide and Plasma-Activated Buffered Solution (PABS) was compared. In the laboratory trial, the inner surfaces of liners were contaminated with pure cultures of Escherichia (E.) coli, Staphylococcus (S.) aureus, Streptococcus (Sc.) uberis and Sc. agalactiae. The disinfection of the contaminated liners with the disinfectants resulted in a significant reduction in bacteria with values averaging 1 log for E. coli, 0.7 log for S. aureus, 0.7 log for Sc. uberis and 0.8 log for Sc. agalactiae. The highest reduction was obtained for contamination with E. coli (1.3 log) and Sc. uberis (0.8 log) when PABS was applied and for contamination with S. aureus (1.1 log) and Sc. agalactiae (1 log) when Peracetic Acid Solution (PAS) was used. Treatment with sterile water only led to an average reduction of 0.4 log. In the field trial, after the milking of 575 cows, the liners were disinfected and the total microorganism count from the liner surface was performed. The reduction was measured against an untreated liner within the cluster. Although a reduction in microorganisms was achieved in the field trial, it was not significant. When using PAS, a log reduction of 0.3 was achieved; when using PABS, a log reduction of 0.2 was obtained. The difference between the two disinfection methods was also not significant. Treatment with sterile water only led to a reduction of 0.1 log. The results show that spray disinfection under these circumstances does result in a reduction in the bacteria on the milking liner surface, but for effective disinfection a higher reduction would be preferred.

Efficacy of Unsupervised Self-Collected Mid-Turbinate FLOQSwabs for the Diagnosis of Coronavirus Disease 2019 (COVID-19).

CONTEXT: The Global Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic has resulted in explosive patterns of transmission in most countries. Nasopharyngeal swabs were the specimen's collection tools recommended for the diagnosis of SARS-CoV-2 infection, and for monitoring infection outbreaks in communities. Our objective was to report the quality and efficacy of unsupervised self-collected mid turbinate "dry FLOQSwabs" (MT FLOQSwabs) (56380CS01, Copan). There were 111 specimens collected for the study: 36 by health care personnel, from themselves, to verify the quality and efficacy of mid-turbinate swabs; 75 to compare and assess the diagnostic performance, among health care personnel, of nasopharyngeal swabs and self-collected mid-turbinate FLOQSwabs. A collection of 51 specimens was enrolled to define the efficacy of the Testami program (validation). Our analyses demonstrate that self-collected mid-turbinate dry swabs ensure an accuracy of 97.3%, as compared to the standard nasopharyngeal swabs collected by health care workers. Furthermore, the mid-turbinate FLOQSwabs can be stored without medium for six days at room temperature without affecting the molecular diagnosis of the SARS-CoV-2 virus infection. Self-collection of diagnostic specimens at home could offer an avenue to increase testing availability for SARS-CoV-2 infection without asking people to travel to a clinic or a laboratory, thus reducing people's exposure to infection. Our findings demonstrate that unsupervised self-collection swabs, transported dry, are sensitive, practical and easy-to-use tools and should be considered for diagnosis of SARS-COV-2 and coronavirus disease 2019 (COVID-19) surveillance.

Easing diagnosis and pushing the detection limits of SARS-CoV-2.

Rigorous testing is the way forward to fight the coronavirus disease 2019 pandemic. Here we show that the currently used and most reliable reverse transcription-polymerase chain reaction-based severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) procedure can be further simplified to make it faster, safer, and economical by eliminating the RNA isolation step. The modified method is not only fast and convenient but also at par with the traditional method in terms of accuracy, and therefore can be used for mass screening. Our method takes about half the time and is cheaper by ∼40% compared to the currently used method. We also provide a variant of the new method that increases the efficiency of detection by ∼30% compared to the existing procedure. Taken together, we demonstrate a more effective and reliable method of SARS-CoV-2 detection.

Bacterial Load of the Teat Apex Skin and Associated Factors at Herd Level.

In order to reduce antimicrobial treatment and prevent environmental mastitis, the aim of the present study was to investigate associations between herd level factors and microbial load on teat ends with environmental mastitis pathogens. Quarterly farm visits of 31 dairy farms over a one-year period were used for statistical analysis. During each farm visit, teat-skin swabs, bedding and air samples were taken and management practices and herd parameters were documented. Total mesophilic bacteria, esculin-positive streptococci and coliform bacteria were examined in the laboratory procedures from teat skin and environmental samples. Esculin-positive streptococci and coliform bacteria on teat ends increased with high temperature-humidity indices (THI) in the barn during the spring and summer. Significantly more coliform bacteria on teat ends were found in herds with an increased percentage of normal or slightly rough teat ends. Cleaning cubicles more frequently, pre-cleaning teats before milking as well as post-dipping them after milking had a decreasing effect of teat-skin load with total mesophilic and coliform bacteria at the herd level. To conclude, teat-skin bacterial load with environmental pathogens is subject to fluctuations and can be influenced by aspects of farm hygiene.

Liquid and Dry Swabs for Culture- and PCR-Based Detection of Colonization with Methicillin-Resistant Staphylococcus aureus during Admission Screening.

Rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) colonization status facilitates isolation and decolonization and reduces MRSA infections. Liquid but not dry swabs allow fully automated detection methods. However, the accuracy of culture and polymerase chain reaction (PCR) using liquid and dry swabs has not been analyzed. We compared different swab collection systems for routine nasal-throat MRSA screening in patients admitted to a tertiary care trauma center in Germany. Over 3 consecutive months, dry swabs (month 1), ESwabs (month 2), or MSwabs (month 3) were processed using Cepheid GeneXpert, Roche cobas and BD-MAX™ MRSA tests compared to chromogenic culture. Among 1680 subjects, the MRSA detection rate using PCR methods did not differ significantly between dry swabs, ESwab, and MSwab (6.0%, 6.2%, and 5.3%, respectively). Detection rates using chromogenic culture were 2.9%, 3.9%, and 1.9%, using dry, ESwab, and MSwab, respectively. Using chromogenic culture as the "gold standard", negative predictive values for the PCR tests ranged from 99.2-100%, and positive predictive values from 33.3-54.8%. Thus, efficient and accurate MRSA screening can be achieved using dry, as well as liquid E- or MSwab, collection systems. Specimen collection using ESwab or MSwab facilitates efficient processing for chromogenic culture in full laboratory automation while also allowing molecular testing in automated PCR systems.

An evaluation of clinical performance of FTA cards for HPV 16/18 detection using cobas 4800 HPV Test compared to dry swab and liquid medium.

BACKGROUNDS: Effective dry storage and transport media as an alternative to conventional liquid-based medium would facilitate the accessibility of women in the low-resource settings to human papillomavirus (HPV)- based cervical cancer screening. OBJECTIVE: To evaluate analytical and clinical performance of indicating FTA™ Elute Cartridge (FTA card) for the detection of HPV16/18 and cervical precancerous lesions and cancer compared to dry swab and liquid medium. STUDY DESIGN: Ninety patients with abnormal cytology and/or HPV infection were included for analysis. Three specimens of cervical exfoliated cells from each woman were randomly collected by FTA card, dry swab or liquid-based medium prior to colposcopy examination. The subsequent HPV DNA tests were performed on cobas 4800 HPV platform. RESULTS AND CONCLUSIONS: High-risk HPV (hrHPV) positivity rate was 63.3%, 62.2% and 65.6% for samples collected by FTA card, dry swab and liquid medium, respectively. The overall agreements and kappa values for the detection of hrHPV, HPV 16 and HPV 18 between FTA card and liquid-based medium were 88.9% (κ=0.76), 97.8% (κ=0.94) and 100% (κ=1.0),respectively; between FTA card and dry swab were 92.1% (κ=0.83), 94.5% (κ=0.87) and 100% (κ=1.0), respectively. The performances of hrHPV tested by FTA card, dry swab, and liquid-based medium for detecting CIN2+ were comparable in terms of the sensitivity and specificity. The specificity of detection of CIN2+ by HPV16/18 increased by approximately 40% compared to hrHPV for any medium albeit at cost of a moderate loss of sensitivity. Dry medium might offer an alternative to conventional liquid-based medium in the HPV-based cervical cancer screening program especially in low-resource settings but still needs further evaluation.

Comparison of DRY and WET vaginal swabs with cervical specimens in Roche Cobas 4800 HPV and Abbott RealTime High Risk HPV tests.

BACKGROUND: Self-collected vaginal swab samples have been proposed as an alternative specimen collection method for human papillomavirus (HPV) DNA detection. OBJECTIVES: Two vaginal swabs (a cone-shaped flocked swab (DRY) and a L-shape FLOQSwab with 2mL eNAT transport medium (WET)) were compared to standard cervical samples for HPV DNA testing. Additionally, they were also compared by using Roche Cobas 4800 HPV (Roche_HPV) and Abbott Real-time High Risk HPV (Abbott_HPV) tests. STUDY DESIGN: Ninety-six women were prospectively enrolled from the National Cancer Center in Korea between June and August 2015. WET and DRY vaginal swabs and cervical specimens were collected. Roche_HPV and Abbott_HPV tests were performed. The Roche_HPV test on cervical specimens was used as reference. RESULTS: The observed agreements (kappa) of Roche_HPV and Abbott_HPV between WET and DRY swabs were 89.6% (0.790, 95% confidence interval (95% CI): 0.667-0.913) and 91.7% (0.833, 95%CI: 0.723-0.943), respectively. No statistical difference was observed between WET and DRY swabs (p>0.05 for all comparisons). For HPV16/18, the sensitivity/specificity of Roche_HPV on the DRY and WET samples presented 93.8%/96.3% and 87.5%/97.5%, respectively. For other High Risk HPV (hrHPV), the sensitivity/specificity of Roche_HPV on the DRY and WET swabs presented 91.9%/91.5% and 97.3%/98.3, respectively. The sensitivity/specificity of the Abbott_HPV on the DRY and WET swabs were 93.8%/98.8%, 87.5%/98.8% for HPV16/18, and 91.9%/93.2%, 100.0%/93.2% for other hrHPV, respectively. CONCLUSIONS: HPV tests performed similarly when using vaginal DRY and WET swab samples. Using DRY and WET swabs to collect vaginal specimens could be an alternative to collecting cervical samples for HPV DNA testing.

Use of swabs for dry collection of self-samples to detect human papillomavirus among Malagasy women.

BACKGROUND: Most women in developing countries have never attended cervical screening programmes and often little information exists on type-specific human papillomavirus (HPV) prevalence among these populations. Self-sampling for HPV testing (self-HPV) using a dry swab may be useful for establishing a screening program and evaluating HPV prevalence. Our aim was to evaluate self-HPV using a dry swab stored at room temperature. METHODS: This community-based study in Madagascar consisted of 449 women aged 30-65. Eligible women were provided a dry swab to perform self-HPV. HPV analysis was accomplished by two different real-time PCR tests using the same extracted DNA from the samples. RESULTS: Overall, 52 (11.6 %) specimens were invalid for HPV detection. The delay between sampling and laboratory processing of DNA extraction considerably increased invalid results. Overall HPV prevalence of 14 hrHPV types detected by the two PCR tests was found to be 38.2 % (n = 152). Distribution of 19 hrHPV and 9 low-risk HPV (lrHPV) types revealed most frequently 53 and 68 among hrHPV and HPV 54, HPV 70 and HPV 42 among lrHPV. Agreement between the two PCR methods for any of the 14 high-risk HPV (hrHPV) strains detected was 89.9 % (kappa = 0.77, 95 % CI: 0.71-0.84). In 385 (85.7 %) samples the DNA load of ß-globin demonstrated a signal with medium or high level copies. Conversely, in 28 (60.9 %) invalid samples the signal was undetectable. The HPV-DNA load signal was predominantly of intermediate level (58.5 %, n = 218). CONCLUSIONS: Self-HPV using a dry swab stored at room temperature could be a useful method for HPV screening and for conducting population-based surveys on HPV prevalence in resource-poor settings.

A pilot study to compare dry cervical sample collection with standard practice of wet cervical samples for human papillomavirus testing.

BACKGROUND: For human papillomavirus (HPV) DNA detection, specimen collection and transportation using a dry swab without transport medium has advantages, in various situations, over liquid media. OBJECTIVE: In this pilot study we evaluated whether a dry cervical sample taken with a flocked swab (dry sample) is a valid alternative for HPV DNA testing compared with the standard practice of a wet sample taken with a cyto-broom placed directly into liquid media (wet sample). STUDY DESIGN: Women attending the dysplasia clinic at the Royal Women's Hospital, Melbourne Australia between November 2013 and February 2014 were enrolled. During colposcopic examination, a practitioner collected wet and dry cervical samples, with the order of collection randomised. In the laboratory both samples were left for a week before being tested for 14 high-risk HPV types using the Roche Cobas 4800 test. RESULTS: Overall, 209 had valid HPV results from both samples. The observed agreement for HPV detection between wet and dry samples was 92.8% and kappa was 0.85 (95% confidence interval (95% CI): 0.78-0.92). There was no statistical difference in the percent HPV positive for each sample (p = 0.30). HPV testing of the dry sample had an 88.5% (95% CI: 79.9-94.3%) sensitivity for HPV detected using the wet specimen. For the HPV results categorized hierarchically, there was 92.8% overall agreement and a kappa of 0.87 (95% CI = 0.80-0.93) for the paired results. CONCLUSION: Using dry flocked swabs to collect cervical cells is a valid alternative to collecting wet samples for HPV DNA testing using a PCR based test.

Accuracy of dry vaginal self-sampling for detecting high-risk human papillomavirus infection in cervical cancer screening: a cross-sectional study.

OBJECTIVE: Cervical cancer screening coverage remains insufficient in most countries. Testing self-collected samples for high-risk human papillomavirus (HR-HPV) could be an alternative to the Pap smear, but costs, sampling methods and transport issues hamper its wide use. Our objective was to compare diagnostic accuracy of 2 vaginal self-collection methods, a dry swab (vsc-DRY) or swab in liquid medium (vsc-LIQ), for detecting HR-HPV cervical infection assessed by a cervical clinician-collected sample in liquid medium (ccc-LIQ). METHODS: Women 20 to 65 years attending a Pap smear were recruited between September, 2009 and March, 2011. Each sample (3 per woman) underwent HPV DNA testing. Samples were classified as HR-HPV+ with detection of at least one HR-HPV or probable HR-HPV type. RESULTS: Of 734 women included, 722 had complete HPV data. HR-HPV was detected in 20.9% of ccc-LIQ samples. Estimated sensitivity and specificity to detect HR-HPV in vsc-DRY samples were 88.7% and 92.5%, respectively, and in vsc-LIQ samples, 87.4% and 90.9%. Cytology findings were abnormal for 79 women (10.9%): among 27 samples of low-grade squamous intraepithelial lesions, 25 were HR-HPV+ in vsc-DRY, vsc-LIQ and ccc-LIQ samples. Among 6 samples of high-grade squamous intraepithelial lesions, all were HR-HPV+ in vsc-DRY samples, 1 was HR-HPV- in vsc-LIQ samples and 1 was HR-HPV- in ccc-LIQ samples. CONCLUSIONS: Vaginal self-sampling with a dry swab is accurate to detect HR-HPV infection as compared with cervical clinician-collection and accurate as compared with cytology results. This cheap and easy-to-ship sampling method could be widely used in a cervical cancer screening program.