Characterization and long-read sequencing of biofilms formed by the microbiota present on inert surfaces in poultry slaughterhouses.

Cross-contamination from inert slaughterhouse surfaces is among the main sources of contamination of poultry. The objective of the research reported here was to characterize the biofilms formed by the microbiota present on various surfaces in two poultry slaughterhouses in north-western Spain. Forty-four samples (22 from each slaughterhouse) were taken by swab rubbing at different points along the processing line (from stunning to cutting). The microbiota on all surfaces was able to form biofilms, which were studied by scanning confocal laser microscopy. The total biovolume in the observation field of 16,078.24 µm2 ranged from 22,106.8 ± 5544.3 µm3 to 414,229.6 ± 1621.0 µm3. Average values were higher in abattoir A than in abattoir B, with significant differences (P < 0.05) between surfaces. The percentage of biovolume of Gram-positive bacteria ranged between 0.02 % and 5.38 %. The highest percentages of Gram-positive bacteria were detected towards the beginning of the processing line. The microbiota of the biofilms was identified using long-read sequencing techniques (Oxford Nanopore). The predominant genera (found in >50.0 % of the biofilms) were Pseudomonas, Citrobacter, Klebsiella, Serratia, Escherichia, Enterobacter, Stenotrophomonas, Salmonella, Shewanella, Acinetobacter and Aeromonas. In addition, some pathogenic bacteria were detected, including Salmonella (31 surfaces), Yersinia enterocolitica (12), Escherichia coli O157:H7 (6), Campylobacter spp. (4) and Listeria monocytogenes (3). This research work has permitted identification of the most contaminated surfaces in poultry abattoirs and can serve as a starting point for the design of more effective cleaning and disinfection protocols.

Mediated self-assembled gold nanoclusters with mesoporous silica particles to boost fluorescence for enhanced on-site monitoring of organophosphate pesticides.

Accurate detection of organophosphate pesticides (OPs) is paramount for ensuring food safety. Dendritic mesoporous silica sphere was employed to confine gold nanoclusters (AuNCs@dmSiO2) to ameliorate fluorescent property of AuNCs. A AuNCs@dmSiO2-based fluorescent method was developed for OPs sensing. Identification of Cu2+ by AuNCs quenched AuNCs@dmSiO2 fluorescence. Interaction between Cu2+ and generated thiocholine in catalysis of acetylcholinesterase (AChE) caused fluorescence enhancement. OPs, an inhibitor of AChE, suppressed thiocholine production to cause fluorescence quenching. Based on fluorescent variation, a fluorescent method was proposed for OPs by selecting paraoxon as a model within range of 0.05-25.0 ng/mL with a limit of detection (LOD) of 0.032 ng/mL. Besides, a portable test swab was prepared for on-site monitoring OP paraoxon with a smartphone-based 3D-printing portable device with a LOD of 0.65 ng/mL. This work is highlighted by the inspiration of designing highly fluorescent AuNCs, and the provision of a viable avenue for OPs-related food analysis.

Oropharyngeal swab sampling for PRRSV detection in large-scale pig farms: a convenient and reliable method for mass sampling.

BACKGROUND: Porcine reproductive and respiratory syndrome virus (PRRSV) has significant productivity and economic impacts in swine herds. Accurately determining the PRRSV status at the herd level is crucial for producers and veterinarians to implement strategies to control and eliminate the virus from infected herds. This study collected oropharyngeal swabs (OSs), nasal swabs (NSs), oral fluid swabs (OFs), rectal swabs (RSs), and serum samples continuously from PRRSV challenged pigs under experimental conditions and growing pigs under field conditions. Additionally, OSs and serum samples were collected from individual sows from 50 large-scale breeding farms, and the collection of OSs does not require the sows to be restrained. Ct values of PRRSV were detected in all samples using real-time reverse transcriptase-polymerase chain reaction (RT-qPCR). RESULTS: In PRRSV challenged pigs, OSs showed a higher PRRSV-positive rate until the end of the observation period. The Ct values of OSs were significantly lower than those of NSs, OFs, and RSs at 2, 8, 12, 14 and 20 days post-challenge (DPC) (P < 0.05). For growing pigs, the positivity rate of PRRSV in OSs was higher than that in other sample types at 30, 70, and 110 days of age. In sows, 24,718 OSs and 6259 serum samples were collected, with PRRSV-positive rate in OSs (9.4%) being significantly higher than in serum (4.1%) (P < 0.05). However, the Ct values of PRRSV RNA in serum were significantly lower than those in OSs (P < 0.001). CONCLUSIONS: The OSs sample type yielded higher PRRSV-positive rates for longer periods compared to NSs, RSs, OFs and serum samples for PRRSV detection in infected pigs. Therefore, OSs has a good potential to be a convenient, practical, and reliable sample type for implementing mass sampling and testing of PRRSV in large-scale pig farms.

Validation of the Diabetomics CovAB SARS-CoV-2 antibody test in children: comparison with serology.

Monitoring antibody prevalence is a valuable tool to evaluate the burden of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a community, identify risk factors, and assess the impact of clinical and public health intervention strategies. The antibody prevalence of SARS-CoV-2 in children in the United States in early 2022 was estimated by the Centers for Disease Control and Prevention to be 74.2%, using seroprevalence from a variety of sources. A study by the New Jersey Department of Health in late 2022/early 2023 in unvaccinated children found a lower prevalence, 68% when using a gum swab method to detect antibodies. This study compared the accuracy of the gum swab method to detect antibodies with simultaneously obtained serological samples in additional children. This cross-sectional study recruited well children, not vaccinated for SARS-CoV-2, aged 18 months to 11 years, who were scheduled for routine bloodwork at an inner-city university-based pediatric clinic. With parental consent, an extra 5 cc of blood and a gum swab sample were collected. Results from Diabetomics CovAb SARS-CoV-2 gum swab antibody test and Rutgers New Jersey Medical School enzyme-linked immunosorbent assay serology test for spike protein antibody were compared. The seropositivity of these paired samples was compared using McNemar's test, Cohen's kappa statistic, and other diagnostic accuracy statistics. From June through August 2023, 86 children were recruited. Antibody positivity by gum swab was 70.9% and by serology was 87.2%. The Cohen's kappa statistic was 0.39 indicating minimal agreement and McNemar's test was significant (P-value of 0.0010). Compared with serology, gum swab was 78.7% sensitive (95% CI 68.7% to 87.3%) and 81.8% specific (95% CI 48.2% to 97.7%). Positive and negative predictive values were 97.5% and 29.9%, respectively, and accuracy was 79.0%. Sensitivity in non-Hispanic versus Hispanic children was 74.2% versus 82.5%, and in children 6-11 years versus 18 months to 5 years, it was 74.2% versus 81.8%. While the gum swab method of antibody detection is not as sensitive or specific as serology, sample collection can be done in settings where phlebotomy is not feasible. This method could be useful in non-clinical settings such as surveillance, for assessing epidemiological trends and associations. IMPORTANCE: Recently a study determining the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in unvaccinated children in NJ (Katic et al. 2023. Pediatric Academic Societies Meeting; Washington, D.C. https://2023.pas-meeting.org/searchbyposterbucket.asp?bm=Public+Health+%26+Prevention&t=Public+Health+%26+Prevention&pfp=Track) was conducted using a gum swab method for antibody detection. The Diabetomics CovAB test, which qualitatively identifies antibodies to SARS-CoV-2 spike protein, is a point-of-care, low-cost test, that is easy to administer in children. While this test provides sensitive and specific results in adults [US Food and Drug Administration (FDA). 2022. Center for devices and radiological health. EUA authorized serology test performance. Available from: https://www.fda.gov/medical-devices/covid-19-emergency-use-authorizations-medical-devices/eua-authorized-serology-test-performance], data on its accuracy in children is lacking. As a follow-up to the above-mentioned study, we compared the results of the gum swab test to a serologic antibody test. We found that the gum swab test was inferior to serology but was fairly sensitive and specific with a high positive predictive value. While the test is not ideal for diagnostic purposes in children it can be a valuable tool for public health officials and pediatricians to understand the extent of past health interventions.

Epigenetic Age Estimation by Detecting DNA Methylation Status in Buccal Swabs.

The analysis of DNA methylation (DNAm) levels at specific CpG sites represents one of the most promising molecular techniques for estimating an individual's age. To date, a considerable number of studies have reported the development of age prediction models on the basis of DNAm in body fluids, with only a few utilizing buccal swabs. The objective of this study was to identify age-dependent methylation CpG sites in three different genes (HOXC4, TRIM59, and ELOVL2) in buccal swab samples from the Chinese Han population. A total of 461 buccal swabs, with an age range of 0.4-80.8 years, were divided into a training set (n = 325) and a validation set (n = 136). Samples were analyzed by pyrosequencing in order to identify age-related genes with correlation coefficient. A random forest regression model was ultimately proposed, including eight CpGs in three genes, with a mean absolute error (MAE) of 2.119 years. The model performs independent validation set with an MAE of 4.391 years. Our findings illustrate that buccal swabs present a suitable alternative to biological traces for age prediction based on DNAm pattern using pyrosequencing and random forest regression, offering the additional advantage of being collected noninvasively.

Evaluation of Screening Results for Vancomycin-Resistant Enterococci: Three-Year Surveillance.

Background: Enterococci are facultative anaerobic, binary, or chained Gram-positive cocci. The gastrointestinal colonization of hospitalized patients is the most important reservoir of vancomycin-resistant enterococci. We aimed to evaluate retrospectively the screening results of vancomycin-resistant enterococci, studied by the simultaneous (real-time) polymerase chain reaction method on rectal swabs of adult and pediatric patients hospitalized in our hospital in 2019-2021. Methods: Adult and pediatric patients were included in our study between Jan 2019 and Dec 2021. The results of vancomycin-resistant enterococci, studied with the real-time polymerase chain reaction method from rectal swabs sent from intensive care units and services, were analyzed retrospectively. Isolation of the samples was performed using the Fluorion VRE QLP 1.0 real-time polymerase chain reaction kit (Iontek, Turkey), and detection was performed with the Fluorion Detection System (Iontek, Turkey) real-time polymerase chain reaction device. Results: Overall, 31,725 patients were included in our study. When evaluated in order of years, in 2019, 379 (7%) of 5,389 adults, 322 (7.4%) of 4,003 children, 234 (5.5%) of 4,185 adults in 2020, 157 (2.4%) of 6,499 children, and in 2021, vancomycin-resistant enterococci were detected in 469 (7.5%) of 6,232 adults and 224 (4.1%) of 5,417 children. Conclusion: The prevalence of vancomycin-resistant enterococci is greater in adults, particularly in intensive care units, compared to children. Infection control precautions and training be augmented in high-risk clinics, while the unnecessary utilization of glycopeptides should be limited.

Oral swabs as a proxy for direct ruminal microbiome sampling in Holstein dairy cows is correlated with sample color.

Using oral swabs to collect the remnants of stomach content regurgitation during rumination in dairy cows can replicate up to 70% of the ruminal bacterial community, offering potential for broad-scale population-based studies on the rumen microbiome. The swabs collected from dairy cows often vary widely with respect to sample quality, likely due to several factors such as time of sample collection and cow rumination behavior, which may limit the ability of a given swab to accurately represent the ruminal microbiome. One such factor is the color of the swab, which can vary significantly across different cows. Here, we hypothesize that darker-colored swabs contain more rumen contents, thereby better representing the ruminal bacterial community than lighter-colored swabs. To address this, we collected oral swabs from 402 dairy cows and rumen samples from 13 cannulated cows on a research farm in Wisconsin, United States and subjected them to 16S rRNA sequencing. In addition, given that little is known about the ability of oral swabs to recapitulate the ruminal fungal community, we also conducted ITS sequencing of these samples. To correlate swab color to the microbiota we developed and utilized a novel imaging approach to colorimetrically quantify each swab from a range of light to dark. We found that swabs with increasing darkness scores were significantly associated with increased bacterial alpha diversity (p < 0.05). Lighter swabs exhibited greater variation in their community structure, with many identified amplicon sequence variants (ASVs) categorized as belonging to known bovine oral and environmental taxa. Our analysis of the fungal microbiome found that swabs with increasing darkness scores were associated with decreased alpha diversity (p < 0.05) and were also significantly associated with the ruminal solids fungal community, but not with the ruminal liquid community. Our study refines the utility of oral swabs as a useful proxy for capturing the ruminal microbiome and demonstrates that swab color is an important factor to consider when using this approach for documenting both the bacterial and fungal communities.

The Acceptability and Feasibility of Self-Collected HPV Testing for Cervical Cancer Screening Among Black and Latinx Women in Chicago: Perspectives from the Community.

Introduction: Cervical cancer disproportionally affects Black and Latinx women in Chicago. Black and Latinx women have a higher incidence of cervical cancer diagnosis and lower rates of cervical cancer screening than non-Latinx White women. Self-collected high-risk human papillomavirus (HPV) testing has been proposed as a method to address these barriers to screening and prevent cervical cancer. Objective: This study aimed to understand the feasibility and acceptability of self-collected HPV testing as a novel approach to address barriers to cervical cancer screening for Black and Latinx women in Chicago. Methods: Semistructured interviews with 17 Black and Latinx community members of the greater Chicago area were conducted. Thematic analysis using inductive and deductive coding was completed. Results: Findings from qualitative interviews indicate strong support for self-collected HPV testing among community members. They expressed a preference for self-collected HPV testing due to the comfort, control, and reduced anxiety it offers. Financial constraints, prioritization of other life demands, and past trauma were identified as substantial barriers to traditional cervical screening. Conclusion: Self-collected HPV testing could address barriers to cervical cancer screening by providing a less-invasive, patient-centered alternative to traditional methods. Self-collected HPV testing should be made accessible, be integrated into existing cervical cancer screening programs, and be covered by health insurance.

The Future of Cervical Cancer Screening.

Purpose: Cervical cancer remains a significant health concern, particularly in developing countries, where it is a leading cause of cancer-related deaths among women. Innovative technologies have emerged to improve the efficiency, cost-effectiveness, and sensitivity of cervical cancer screening and treatment methods. This study aims to explore the various approaches for the detection and treatment of human papillomavirus (HPV), cervical dysplasia (CD), and cervical cancer, highlighting new technologies and updated screening strategies in developing areas. Patients and Methods: A comprehensive literature search was conducted using PubMed to identify relevant publications on the subject of cervical cancer screening and HPV detection. Results: HPV infection and cervical cancer continue to pose significant global health challenges. Emerging technologies such as rapid, low-cost HPV testing combined with high-resolution digital colposcopy and artificial intelligence interpretation hold promise for efficient and sensitive screening. Advancements in HPV vaccine distribution, high-risk HPV screening, DNA methylation assays, dual-stain cytology, lab-on-chip assays, and deep learning technologies offer new avenues for improved detection and risk stratification.Research and innovations in detection and treatment methods are crucial for reducing the burden of these diseases worldwide. Conclusion: Screening for HPV and CD plays a pivotal role in reducing the risk of cervical cancer-related mortality. The development of novel technologies, along with efforts to enhance global health equity and integrate cervical cancer prevention with HIV screening and treatment programs, represent critical steps toward achieving comprehensive cervical cancer screening on a global scale.

A cotton swab platform for fluorescent detection of aluminum ion in food samples based on aggregation-induced emission of carbon dots.

A novel portable cotton swab based on nitrogen-doped carbon dots (NCDs) for Al3+ detection was constructed for the first time. NCDs with bright green fluorescence were prepared by hydrothermal method with phenylhydrazine hydrochloride and 3-hydroxy-2-naphthoic acid hydrazide as precursors. The surface of NCDs was exposed to abundant functional groups (such as amino, carboxyl, hydroxyl, etc.), which was helpful for the formation of complexes between NCDs and Al3+. In the presence of Al3+, the aggregation of NCDs obviously induced their fluorescence enhancement due to the aggregation-induced emission (AIE) of NCDs. Furthermore, the quantum yield (QY) of NCDs was enhanced by 12 times with Al3+, and the fluorescence lifetime was increased by 7.54 ns. The fluorescence intensity was linearly correlated with the concentration of Al3+ (2.5-300 µM), and the limit of detection was 0.76 µM. Moreover, for the portable way, cotton swabs were successfully employed to construct the sensors for the detection of Al3+ in food samples. This proposal has potential for the application in food analysis.

Challenges in Diagnosis of COVID-19 Pneumonia under Ocrelizumab and De-Risking Strategies in Multiple Sclerosis-The Elephant Is (Still) in the Room.

Severe SARS-CoV-2 infections may still be observed in people bearing risk factors, such as the use of anti-CD20 monoclonal antibodies (mAbs), which are adopted in several autoimmune disorders including multiple sclerosis (MS). COVID-19 diagnosis is routinely based on nasopharyngeal swab testing, but suboptimal sensitivity for SARS-CoV-2 detection compared to bronchoalveolar lavage (BAL) may lead to misdiagnosis in some cases. Such diagnostic issues were described in a few MS patients receiving anti-CD20 mAbs, including middle-aged people and lacking information on subsequent MS therapeutic management, a debated topic as no evidence-based guidance on de-risking strategies is currently available. Here, we report the case of a young MS patient who developed severe COVID-19 pneumonia under treatment with the anti-CD20 mAb ocrelizumab, and who was finally diagnosed with SARS-CoV-2 by BAL despite repeatedly negative nasopharyngeal swabs. Ocrelizumab was then discontinued, and treatment with a sphingosine-1 phosphate receptor modulator was started, followed by maintenance of clinical and radiological MS stability. Challenges in diagnosing COVID-19 pneumonia in people without risk factors other than immunomodulatory treatment are hence discussed, as well as potential strategies for de-risking MS therapies. The latter topic is increasingly debated based on raising concerns for potential long-term safety issues of high-efficacy treatments, including anti-CD20 mAbs.

Predictive values of methicillin-resistant Staphylococcus aureus nasal swabs for pneumonia in burn ICU patients.

INTRODUCTION/OBJECTIVE: This retrospective cohort study aimed to determine the sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) of MRSA nasal swabs for pneumonia in burn-injured intensive care unit (ICU) patients. METHODS: Patients 18 years or older admitted to the Burn ICU at a tertiary medical center from 2016 to 2021 were included if they had any burns, a pneumonia ICD-10 code, an MRSA nasal swab obtained during admission, and any respiratory cultures associated with at least five consecutive days of antibiotics. RESULTS: There were 267 occurrences of pneumonia across 136 patients. MRSA nasal swabs had an overall sensitivity of 39 %, specificity of 98.7 %, PPV of 84.2 %, and NPV of 89.9 %. MRSA nasal swabs obtained less than seven days from antibiotic initiation had a specificity of 98.6 % and NPV of 98.6 %; meanwhile, swabs obtained at least seven days from antibiotic initiation had a specificity of 98.7 % and NPV of 86.4 %. CONCLUSIONS: The high specificity and NPV indicate that negative MRSA nasal swabs obtained less than seven days from antibiotic initiation may be used to de-escalate anti-MRSA antibiotics in clinically stable burn-injured patients with suspicion of pneumonia. The decrease in NPV suggests that it may be beneficial to obtain a repeat swab periodically.

Impact of hand hygiene interventions on handwashing practices and microbial risk: A study in an orphanage-based school in Pakistan.

BACKGROUND: Orphaned children are often deprived of quality care, making them more susceptible to diseases due to inadequate hand hygiene. The study aimed to assess the prevalence of hand hygiene practices and detect bacterial loads on children's hands before and after hygiene interventions in an orphanage school. METHODS: The study enrolled all the orphan children registered with the Save Our Souls children's orphanage school in Pakistan. Handwashing practices and swab samples from the hand was collected to evaluate the impact of hand hygiene practices on bacterial load. The Quantitative Microbial Risk Assessment model was used to predict the health risk. RESULTS: The study identified the 2 most common bacteria: Staphylococcus aureus and Escherichia coli. The bacterial contamination was significantly reduced after the intervention (S aureus 166 Colony-forming unit (CFU) /mL and E coli 185 CFU/mL). The higher bacterial ingestion rate was attributed to hand contamination and increased bacteria transfer from hand to mouth. CONCLUSIONS: The multicomponent hand hygiene intervention showed improvement in accessibility to hand hygiene resources and practices. The findings underscore the need for hygiene interventions in orphanage schools to improve health and educational outcomes.

Development and Diagnosis Performance of IgM-Based Rapid Antigen Test for Early Detection of SARS-CoV-2 Infection in a Large Cohort of Suspected COVID-19 Cases - USA, Poland, and Sweden, 2021-2022.

Introduction: Antigen testing has been crucial in effectively managing the coronavirus disease 2019 (COVID-19) pandemic. This study evaluated the clinical performance of a nasopharyngeal swab (NPS)-based antigen rapid diagnostic test (Ag-RDT) compared to the gold standard real-time reverse transcription-polymerase chain reaction (RT-PCR) for early detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: We developed an IgM-based rapid antigen test for early detection of SARS-CoV-2 infection. Between July 2021 and January 2022, we analyzed 1,030 NPS samples from participants at three centers in different countries, using both antigen rapid diagnostic tests (Ag-RDT) and RT-PCR. Results: The Ag-RDT demonstrated minimal detection limits as low as 0.1 ng/mL for recombinant N antigen and 100 TCID50/mL for heat-inactivated SARS-CoV-2 virus. Specificity assessments involving four human coronaviruses and 13 other respiratory viruses showed no cross-reactivity. The Ag-RDT assay (ALLtest) exhibited high sensitivity (93.18%-100%) and specificity (99.67%-100%) across all centers. Factors such as cycle threshold (Ct) values and the timing of symptoms since onset were influential, with sensitivity increasing at lower Ct values (<30) and within the first week of symptoms. Conclusion: The ALLtest Ag-RDT demonstrated high reliability and significant potential for diagnosing suspected COVID-19 cases.

Streptococcus ovis associated abortion in an Icelandic mare.

Streptococci are well-known opportunistic bacterial abortifacients in mares. Colonization of the pregnant uterus is considered to happen after transcervical migration of bacteria from the lower genital tract mucosa. Streptococcus ovis is a pathogen mainly associated with inflammatory lesions in sheep. This species has not been reported in association with disease in horses. In the present case, S. ovis was isolated in monoculture from the lung of an 8-months-old equine fetus and was associated with development of acute suppurative bronchopneumonia, umbilical cord cellulitis and placentitis in the cervical star region of the allantochorion. The mare had been in a pasture together with sheep. One week prior to abortion, a double-guarded uterine swab had been inserted into the cervical canal by a veterinarian, who was unaware of the mare being pregnant. This probably damaged the cervical mucus plug thus allowing S. ovis bacteria to pass the cervical canal and colonize the placenta.

Integration of surface swab with optical microscopy for detection and quantification of bacterial cells from stainless-steel surfaces.

Swab sampling is a common method for recovering microbes on various environmental surfaces. Its successful application for a specific target depends on the proper swab method and the following detection assay. Herein, we evaluated critical factors influencing surface swab sampling, aiming to achieve the optimal detection and quantification performance of optical detection for bacterial cells on stainless-steel surfaces. Our results showed the recovery rate of Salmonella enterica (SE1045) cells from the 10 × 10 cm2 stainless-steel surface reached up to 92.71 ± 2.19% when using ammonia bicarbonate-moistened polyurethane foam swabs for gentle collection, followed by ultrasound-assisted release in NH4HCO3 solution. Among the six different foam swabs, the Puritan™ Sterile Large Foam Swab contributed the lowest background noise and highest recovery efficiency when integrated with the optical detection assay. Notably, our method exhibited a strong linear relationship (r2 = 0.9983) between the detected cell numbers and the theoretical number of SE1045 cells seeded on surfaces in the range of 104-107 Colony Forming Units (CFU), with a limit of detection of 7.2 × 104 CFU 100 cm-2. This integration was completed within 2 h, exhibiting the applicable potential in various settings.

Optical detection and enumeration of Escherichia coli and Salmonella enterica using a low-magnification light microscope.

A rapid and cost-effective method for detecting bacterial cells from surfaces is critical to food safety, clinical hygiene, and pharmacy quality. Herein, we established an optical detection method based on a gold chip coating with 3-mercaptophenylboronic acid (3-MPBA) to capture bacterial cells, which allows for the detection and quantification of bacterial cells with a standard light microscope under low-magnification (10×) objective lens. Then, integrate the developed optical detection method with swab sampling to detect bacterial cells loading on stainless-steel surfaces. Using Salmonella enterica (SE1045) and Escherichia coli (E. coli OP50) as model bacterial cells, we achieved a capture efficiency of up to 76.0 ± 2.0 % for SE1045 cells and 81.1 ± 3.3 % for E. coli OP50 cells at 103 CFU/mL upon the optimized conditions, which slightly decreased with the increasing bacterial concentrations. Our assay showed good linear relationships between the concentrations of bacterial cells with the cell counting in images in the range of 103 -107 CFU/mL for SE1045, and 103 -108 CFU/mL for E. coli OP50 cells. The limit of detection (LOD) was 103 CFU/mL for both SE1045 and E. coli OP50 cells. A further increase in sensitivity in detecting E. coli OP50 cells was achieved through a heat treatment, enabling the LOD to be reduced as low as 102 CFU/mL. Furthermore, a preliminary application succeeded in assessing bacterial contamination on stainless-steel surfaces following integration with the approximately 40 % recovery rate, suggesting prospects for evaluating the bacteria from surfaces. The entire process was completed within around 2 h, costing merely a few dollars per sample. Considering the low cost of standard light microscopes, our method holds significant potential for practical industrial applications in bacterial contamination control on surfaces, especially in low-resource settings.

Influence of Solvent Relative Permittivity in Swab Spray Mass Spectrometry.

The influence of solvent properties on ion generation by swab spray ionization was investigated. The ability of a variety of solvents of different relative permittivity, surface tension, and viscosity to form a stable and reproducible electrospray was examined. It is demonstrated that in swab spray ionization, a crucial balance between solvent composition, applied potential, and the solvent flow fed to the swab head must be maintained. The solvent composition was found to significantly affect the shape of the Taylor cone and the emerging cone jet, which eventually have an impact on the resulting ion yield. The results indicate that the relative permittivity of solvents measured under standard conditions is the main factor governing jet shaping, and consequently, the ionization efficacy. Short jets, which are required for maximum ion yield, were observed for solvents with relative permittivity εr higher than 25. Solvents exhibiting lower relative permittivity required the addition of 20% to 60% methanol to limit the jet length and to avoid the ineffective dripping pulsation. The observed effects were compared to conventional electrospray ionization and paper spray ionization.

Traumatic CSF rhinorrhea associated with COVID-19 testing: a case series and systematic review.

BACKGROUND: This report analyzes traumatic anterior skull base CSF leaks following nasopharyngeal swab testing for detection of SARS-CoV-2 in the largest case series to date, combined with a systematic literature review. METHODS: Retrospective multi-institutional case-series of traumatic anterior skull base CSF leak with clear antecedent history of COVID-19 swab was completed. A comprehensive search of databases was performed for the systematic literature review. RESULTS: Thirty-four patients with traumatic CSF leak after COVID-19 nasopharyngeal swab testing were identified. Women were more than twice as likely to experience a CSF leak, as compared to men. The majority of patients (58.8%) had no reported predisposing factor in their clinical history. Common defect sites included the cribriform plate (52.9%), sphenoid sinus (29.4%), and ethmoid roof (17.6%). Four patients (11.8%) presented with meningitis. The median time between the traumatic COVID swab and the detection of CSF leak was 4 weeks (IQR 1-9). Patients with meningitis had a median leak duration of 12 weeks (IQR 8-18). The average leak duration was significantly longer in patients with meningitis compared to without meningitis (p = 0.029), with a moderate effect size (r = - 0.68). Most cases (92.9%) managed with endoscopic endonasal surgical repair were successful. CONCLUSIONS: This report clarifies the presentation, risk factors, and management of CSF leaks attributable to diagnostic nasopharynx swabbing procedures in the COVID-19 era. Timely surgical repair is the recommended management option for such leaks.