Nasal Samples Research Articles

Conjunctival and nasal microflora in patients on topical cyclosporine for dry eye.

Introduction: Dry eye is a common ocular condition causing discomfort and visual disturbances. Anti-inflammatory agents like Cyclosporine A (CsA) are often used in its treatment. However, the impact of CsA on ocular flora remains understudied. This research aimed to evaluate changes in conjunctival and nasal microflora in patients receiving topical cyclosporine for dry eye. Methods: In this cross-sectional study, conjunctival and nasal samples were collected from two groups of dry eye patients. Group 1 consisted of 38 patients using CsA eye drops, while Group 2 included 34 patients using preservative-free artificial tear drops. Bacterial cultures were grown from the samples, and the identified organisms underwent antibiotic susceptibility testing. Additionally, alpha diversity metrics were employed to assess the diversity of bacterial species in the samples. Results: Bacterial growth was observed in 75% of conjunctival samples and 97.22% of nasal samples. Staphylococcus epidermidis was the predominant organism in both groups. Alpha diversity analysis showed no significant differences in Shannon diversity and OTU richness between the groups for most bacterial species. Antibiotic susceptibility tests revealed no substantial variations in resistance patterns between the groups. Conclusion: This study provides valuable insights into the impact of CsA eye drops on conjunctival and nasal flora in dry eye patients. The findings suggest that CsA does not significantly influence the composition, diversity, or antibiotic resistance patterns of ocular flora. Long-term topical cyclosporine treatment for dry eye does not significantly impact conjunctival microflora or lead to antibiotic resistance. These results have important implications for the safe use of CsA in patients undergoing ocular treatments, particularly those at risk of intraocular infections.

Surveillance for COVID-19 associated mucormycosis: A coordinated effort in prevention and management of rhino-orbital mucormycosis

Abstract Context: Patients of coronavirus disease 2019 (COVID-19) and factors inducing a diabetogenic state are at increased risk for rhino-orbital mucormycosis (ROM). Efforts to diagnose ROM in its pre-clinical stage would avoid the disease and its consequences. Aim: This study aimed to diagnose ROM in the pre-clinical stage of the disease in high-risk patients and treat patients accordingly. Settings and Design: This is a single-center, prospective study conducted at a tertiary care center in Northern India in collaboration with departments of Otolaryngology, Internal Medicine, and Mycology. Materials and Methods: Fifty-three high-risk patients were enrolled in the study, and all underwent bedside nasal endoscopy with tissue sampling for fungal culture. Patients with suspicious nasal endoscopy findings but negative fungal culture were prescribed oral posaconazole. Those with positive fungal hyphae on nasal endoscopy and culture underwent surgical intervention followed by intravenous amphotericin B, while the remaining patients were kept on follow-up. Statistical Analysis Used: Statistical analysis was performed using the Statistical Package for Social Sciences software. Results: Among the 53 patients, 13 (24.5%) patients had abnormalities on nasal endoscopy, while the remaining 40 (75.5%) patients had normal nasal mucosal cavities. Seven patients (13.2%) underwent surgery and received intravenous liposomal amphotericin B, while another 7 (13.2%) received oral posaconazole. Thirty-five (66.03%) patients were placed under observation, and 4 (7.5%) patients died due to COVID-19-related illness. Conclusions: Nasal endoscopic-guided tissue sampling for fungal culture serves as a valuable surveillance tool for predicting ROM in COVID-19 patients.

Serotype 3 Experimental Human Pneumococcal Challenge (EHPC) study protocol: dose ranging and reproducibility in a healthy volunteer population (challenge 3)

IntroductionSince the introduction of pneumococcal conjugate vaccines, pneumococcal disease rates have declined for many vaccine-type serotypes. However, serotype 3 (SPN3) continues to cause significant disease and is identified in colonisation...

Intranasal Nose-to-Brain Drug Delivery via the Olfactory Region in Mice: Two In-Depth Protocols for Region-Specific Intranasal Application of Antibodies and for Expression Analysis of Fc Receptors via In Situ Hybridization in the Nasal Mucosa.

A region-specific catheter-based intranasal administration method was successfully developed, established, and validated as reported previously. By using this method, drugs can be applicated specifically to the olfactory region. Thereby, intranasally administered drugs could be delivered via neuronal connections to the central nervous system. Here, we present a detailed protocol with a step-by-step procedure for nose-to-brain delivery via the olfactory mucosa.Fc receptors such as the neonatal Fc receptor (FcRn) and potentially Fcγ receptor IIb (FcγRIIb) are involved in the uptake and transport of antibodies via the olfactory nasal mucosa. To better characterize their expression levels and their role in CNS drug delivery via the nose, an in situ hybridization (ISH) protocol was adapted for nasal mucosa samples and described in abundant details.

Extraction-Free Testing for SARS-CoV-2 in Nasal Swab and Saliva Samples on a Single High-Throughput Platform.

The COVID-19 pandemic introduced an urgent need for rapid and high-throughput testing for SARS-CoV-2. RNA extraction is a major bottleneck for RT-qPCR. We describe a semi-automated, extraction-free RT-qPCR assay for detection of SARS-CoV-2 in nasal swab and saliva samples on a single platform. With a limit of detection of 4 copies/mL, this laboratory developed test performed equivalently to established methods requiring nucleic acid extraction. Five technologists staffing two shifts per day (80 person-hours) processed more than 400,000 samples over 10 months. Patients opted to provide nasal swab samples (83.6%) more frequently than saliva (16.4%), creating the added challenge of producing swab collection kits. Real-world testing data indicated a higher frequency of SARS-CoV-2 detection in saliva (10.1%) compared to nasal swab (7.7%). This cost-effective and quickly scalable approach is suitable for pandemic preparedness planning related to surveillance and diagnostic testing.

Development of a colloidal gold-based immunochromatographic assay for rapid detection of nasal mucosal secretory IgA against SARS-CoV-2.

Infection with SARS-CoV-2 begins in the upper respiratory tract and can trigger the production of mucosal spike-specific secretory IgA (sIgA), which provides protection against reinfection. It has been recognized that individuals with high level of nasal spike-specific IgA have a lower risk of reinfection. However, mucosal spike-specific sIgA wanes over time, and different individuals may have various level of spike-specific sIgA and descending kinetics, leading to individual differences in susceptibility to reinfection. A method for detecting spike-specific sIgA in the nasal passage would be valuable for predicting the risk of reinfection so that people at risk can have better preparedness. In this study, we describe the development of a colloidal gold-based immunochromatographic (ICT) strip for detecting SARS-CoV-2 Omicron spike-specific sIgA in nasal mucosal lining fluids (NMLFs). The ICT strip was designed to detect 0.125 μg or more spike-specific sIgA in 80 μL of NMLFs collected using a nasal swab. Purified nasal sIgA samples from individuals who recently recovered from an Omicron BA.5 infection were used to demonstrate that this ICT strip can specifically detect spike-specific sIgA. The signal levels positively correlated with neutralizing activities against XBB. Subsequent analysis revealed that people with low or undetectable levels of spike-specific sIgA in the nasal passage were more susceptible to SARS-CoV-2 reinfection. This nasal spike-specific sIgA ICT strip provides a non-invasive, rapid, and convenient method to assess the risk of reinfection for achieving precision preparedness.

Screening of vancomycin resistance-associated genes in methicillin-resistant Staphylococcus aureus isolates from cattle, sheep and goats in northwestern Iran.

Staphylococcus aureus is an important pathogen causing a wide range of diseases in both humans and animals. The aim of this research was to screen the vancomycin resistance-associated genes in methicillin-resistant Staphylococcus aureus (MRSA) isolates from animals. A total of 400 nasal swab samples were collected from cattle, goats and sheep between February and August 2022 from both industrial and traditional livestock farms in West Azerbaijan province, Iran. Then, nasal swabs were cultured on mannitol salt agar and molecular analysis was performed after bacteriological examination to confirm the presence of S. aureus. The MecA gene was used to detect MRSA isolates, and two important vancomycin resistance-associated genes, namely vanA and vanB, were searched in the isolates. Out of 400 nasal swabs, 69 samples had S. aureus; of which seven isolates were resistant against methicillin. No vancomycin resistance-associated genes were detected in the MRSA isolates. Based on these findings, vancomycin could be used to treat infections caused by this bacterium.

The Asthma Risk Gene, GSDMB, Promotes Mitochondrial DNA-induced ISGs Expression.

Released mitochondrial DNA (mtDNA) in cells activates cGAS-STING pathway, which induces expression of interferon-stimulated genes (ISGs) and thereby promotes inflammation, as frequently seen in asthmatic airways. However, whether the genetic determinant, Gasdermin B (GSDMB), the most replicated asthma risk gene, regulates this pathway remains unknown. We set out to determine whether and how GSDMB regulates mtDNA-activated cGAS-STING pathway and subsequent ISGs induction in human airway epithelial cells. Using qPCR, ELISA, native polyacrylamide gel electrophoresis, co-immunoprecipitation and immunofluorescence assays, we evaluated the regulation of GSDMB on cGAS-STING pathway in both BEAS-2B cells and primary normal human bronchial epithelial cells (nHBEs). mtDNA was extracted in plasma samples from human asthmatics and the correlation between mtDNA levels and eosinophil counts was analyzed. GSDMB is significantly associated with RANTES expression in asthmatic nasal epithelial brushing samples from the Genes-environments and Admixture in Latino Americans (GALA) II study. Over-expression of GSDMB promotes DNA-induced IFN and ISGs expression in bronchial epithelial BEAS-2B cells and nHBEs. Conversely, knockout of GSDMB led to weakened induction of interferon (IFNs) and ISGs in BEAS-2B cells. Mechanistically, GSDMB interacts with the C-terminus of STING, promoting the translocation of STING to Golgi, leading to the phosphorylation of IRF3 and induction of IFNs and ISGs. mtDNA copy number in serum from asthmatics was significantly correlated with blood eosinophil counts especially in male subjects. GSDMB promotes the activation of mtDNA and poly (dA:dT)-induced activation of cGAS-STING pathway in airway epithelial cells, leading to enhanced induction of ISGs.

COMPARATIVE STUDY OF STAPHYLOCOCCUS AUREUS ISOLATES IN PUS AND NASAL SWABS AMONG LAHORE PATIENTS

Staphylococcus aureus predominately found in nasal and pus samples is one of the major causes of skin infections and invasive diseases like endocarditis, pneumonia, and osteomyelitis. The current study was performed over the 3 month period, from April 2022 to June 2022. A total of 368 participants’ nasal and pus swab specimens were included in this study and were collected from the different hospitals in Lahore. The objective of the study was to discern the relative prevalence of Staphylococcus aureus isolates in Pus and Nasal Swabs among Patients in Lahore. All the collected samples were cultured in sterile conditions on Blood agar, Chocolate agar, MacConkey agar, and Mannitol salt agar according to the standard laboratory guidelines. S. aureus culture plates were identified based on the colonial morphology after 48hrs. Furthermore, isolated bacteria were characterized based on Gram stain, and differential biochemical analyses like the Coagulase test, Oxidase test, Catalase test, Triple sugar iron, Urease test, Indole test, Motility agar test that was performed to reconfirm S. aureus presence in the given pus and nasal specimens. The modified Kirby Bauer disc diffusion method was employed for antimicrobial susceptibility testing and Zone sizes were interpreted according to the Clinical and Laboratory Standard Institute guidelines (2020). From a total of 368 bacterial samples, 283 were pus swabs and 85 were nasal swabs, whereas the most frequently isolated organism was gram-positive Staphylococcus aureus which accounts for 90% (330) of the total samples. Our results showed a 90 % MRSA prevalence rate in Lahore and in our study oxacillin represents high resistance against MRSA in nasal samples, whereas, clindamycin represents high resistance in pus samples respectively. The reason for this increased prevalence of MRSA is due to the irrational use of antibiotics without prior cultural reports, the absence of antimicrobial situation programs in hospitals, and the failure to look at the infection management practices which may be some of the highlighted reasons for this drawback in the hospital and clinical setup.

Pathogenic microbiota in the oral and nasal cavity of healthy individuals as a potential source of infections

Oral microbiota is personalized and varied among human habitats. Detection and identification of pathogenic bacteria and fungi are considered as a strategy for the prevention and control of infectious diseases. To date, no studies have investigated the prevalence of bacterial pathogens and fungi in healthy individuals in Vietnam, particularly the ethnic minorities.This study aimed to evaluate the presence of aerobic bacteria and fungi in the oral and nasal cavities of Jrai healthy individuals in the Central Highland. Oral and nasal swab samples of 140 healthy Vietnamese were collected. Microbiological procedures were performed using standard techniques. A total of 220 bacterial isolates were identified. Of which, 10% (22/220) were potentially pathogenic species including Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Neisseria meningitidis, and Staphylococcus aureus. The most predominant bacteria family was Moraxellaceae (40%, 88/220), followed by Streptococcaceae (36.82%, 81/220). Fungi were not detected in all samples. The oral and nasal cavity of healthy individuals harbors high frequencies of bacterial pathogens, suggesting its potential role as a source for these species. These pathogenic bacteria constitute the threat of their spread and the development of general infections. Infectious microbiota from the oral and nasal cavity should be examined as a preventive screening to control infectious diseases.

Clinical Manifestations and Outcomes of COVID-19 in Diabetes Mellitus People, Yazd, Iran-2021

Objective: Diabetes mellitus is reported to be the third most prevalent comorbidity with COVID-19, after cardio‐cerebrovascular disease and hypertension. Furthermore, diabetes increases the likelihood of admission to the hospital and intensive care unit and death from COVID-19. The aim of the present study was to compare the clinical manifestations and outcomes of COVID-19 in diabetic versus non-diabetic inpatients.
 Materials and Methods: The medical records of 6525 patients with definitive diagnosis of COVID-19 were obtained from the reference COVID-19 diagnosis laboratory from January to July 2021 in Yazd, Iran. Patients were investigated for data on onset, clinical history, and fatality rate. COVID-19-related death was defined as positive RT-PCR in at least one of three nasal samples. Data were analysed using SPSS 24.
 Results: Among inpatients, 21.2% were diabetic. The mean ages of diabetic and non-diabetic patients were 64.45 (±13.87) and 52.98 (±20.36) years, respectively. Diabetics were more likely to be admitted to the intensive care unit (6.8% vs. 5%, P= 0.02) and the fatality rate was higher among them than non-diabetics (22.6% vs. 12%, P< 0.001). In diabetics, the mean age of non-survivors was lower than that of survivors (62.57 vs. 70.48, P= 0.0001) and the frequency of death was higher among men than women (53% vs. 47.5%, P= 0.045). Generally, diabetes has the strongest association with COVID-19 death (P= 0.0001).
 Conclusion: Diabetic patients experience more adverse outcomes because of COVID-19. These findings indicate the need for special attention in relation to prevention treatment against COVID-19 in patients with diabetes.

Downregulation of TET2 Contributes to Nasal Polypogenesis Through Hypoxia-Inducible Factor 1α-Mediated Epithelial-to-Mesenchymal Transition.

Hypoxia-inducible factor 1α (HIF1α) and Tet methylcytosine dioxygenase 2 (TET2) have been reported to mediate nasal polypogenesis through the epithelial-to-mesenchymal transition (EMT). Additionally, HIF1α can regulate the expression and function of TET2. However, the precise mechanism of how TET2 regulates the EMT through HIF1α mediation in nasal epithelial cells is still poorly understood. Nasal tissue samples were collected from patients with chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP), CRS without nasal polyps (CRSsNP), and controls. The expression of HIF1α and TET2 was detected using Western blotting and immunohistochemistry. EMT markers (E-cadherin and vimentin) were also evaluated by immunohistochemistry. Primary human nasal epithelial cells (hNECs) were stimulated with CoCl2 to mimic hypoxia. Vitamin C (VC), a TET2 non-specific activator, and small interfering RNA (siRNA) transfection of TET2 were used to further determine the role of TET2 in hypoxia-induced EMT. Finally, reactive oxygen species (ROS) and Nrf2 were measured to explore the downstream consequences of TET2 in hypoxic hNECs. TET2 levels were lower in the nasal epithelium of CRSwNP patients and were positively correlated with E-cadherin but negatively correlated with vimentin in CRS. However, HIF1α exhibited the opposite pattern and was negatively correlated with TET2 expression. CoCl2-simulated hypoxia led to EMT and increased HIF1α in hNECs in vitro, with simultaneous downregulation of TET2 expression. Addition of VC activated TET2 expression in hNECs, but inhibited EMT and HIF1α expression. Furthermore, siRNA knockdown of TET2 contributed to the EMT in CoCl2-simulated hNECs despite the addition of VC. Finally, TET2 regulated the EMT in hypoxic hNECs through Nrf2 expression and ROS generation. TET2 was negatively correlated with HIF1α and EMT in vivo. TET2 was downregulated by HIF1α, resulting in the EMT in CoCl2-hypoxic hNECs via regulation of oxidative stress in vitro. Hence, TET2 might provide a new therapeutic approach for CRSwNP.

Clinical and Molecular Detections of Lumpy Skin Disease: Possibilities of Co-infection with Foot-and-Mouth Disease

Lumpy skin disease (LSD) and foot and mouth disease (FMD) are notable viral diseases of cattle. This report aimed to highlight the possibilities of an uncommon case of LSD and FMD co-infection. The report also presents the clinical and molecular detection of LSD virus in six crossbred calves and LSD and FMD virus co-infection in a heifer at small-scale dairy farms located in northern Ethiopia. Nasal swabs and tissue samples were collected following aseptic techniques from the six calves suspected of having LSD and a tissue sample from one heifer suspected of having LSD-FMD co-infection and submitted to the laboratory for cell culture and real-time polymerase chain reaction (PCR) tests. Different-sized, firm, painful skin nodules with necrotic centers were seen on different parts of the calves’ body. Swelling of the prescapular and prefemoral lymph nodes, conjunctivitis, and corneal cloudiness were also observed. Uniquely, one heifer was seen with erosive lesions in the oral cavity and tongue, salivation, lameness, and skin nodules. Intracytoplasmic inclusion bodies, a distinctive feature of LSD virus, and the formation of syncytia, a characteristic of FMD virus, were observed in the cell lines. The heifer was diagnosed with a rare co-infection of LSDV and FMDV based on clinical signs, cell culture, and real-time PCR test results. The other six calves were diagnosed with the LSD virus. Treatment with broad-spectrum antibiotics, local wound cleansing, and anti-inflammatory drugs was initiated. Unfortunately, the heifer with LSD-FMD co-infection died while under treatment, and just three calves with LSD were recovered. It can be concluded that vaccination of animals against both diseases and promotion of bio-security protocols in farms is more helpful than treatment, and early case reporting is also warranted to avoid losses related to the diseases.

Delayed Mucosal Antiviral Responses Despite Robust Peripheral Inflammation in Fatal COVID-19.

While inflammatory and immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in peripheral blood are extensively described, responses at the upper respiratory mucosal site of initial infection are relatively poorly defined. We sought to identify mucosal cytokine/chemokine signatures that distinguished coronavirus disease 2019 (COVID-19) severity categories, and relate these to disease progression and peripheral inflammation. We measured 35 cytokines and chemokines in nasal samples from 274 patients hospitalized with COVID-19. Analysis considered the timing of sampling during disease, as either the early (0-5 days after symptom onset) or late (6-20 days after symptom onset) phase. Patients that survived severe COVID-19 showed interferon (IFN)-dominated mucosal immune responses (IFN-γ, CXCL10, and CXCL13) early in infection. These early mucosal responses were absent in patients who would progress to fatal disease despite equivalent SARS-CoV-2 viral load. Mucosal inflammation in later disease was dominated by interleukin 2 (IL-2), IL-10, IFN-γ, and IL-12p70, which scaled with severity but did not differentiate patients who would survive or succumb to disease. Cytokines and chemokines in the mucosa showed distinctions from responses evident in the peripheral blood, particularly during fatal disease. Defective early mucosal antiviral responses anticipate fatal COVID-19 but are not associated with viral load. Early mucosal immune responses may define the trajectory of severe COVID-19.

Correlation between allergic rhinitis and asthma

The concept of the „unified respiratory disease” emphasizes the close connection between the upper and lower respiratory pathways in allergic diseases. The structure and function of the upper and lower respiratory pathways are closely interconnected, forming a single morphofunctional entity. Studies show that allergic rhinitis and asthma share the same inflammatory cells and Th2-type cytokines in nasal and bronchial biopsy samples. Additionally, bronchial challenges can induce inflammation in the nasal area and vice versa, suggesting a close link between the two conditions. The epithelial barrier, through its junctions and constituent proteins, plays an essential role in maintaining homeostasis and protection against external factors, and the complex interactions between these two segments of the respiratory pathways are an important research topic. Tight junctions, adhesion junctions, gap junctions, as well as desmosomes contribute to maintaining epithelial integrity and regulating inflammation. The constituent proteins of these junctions and their interactions play crucial roles in the proper functioning of the epithelial barrier. Respiratory allergens such as dust mites, pollen, pets, and fungi are risk factors for both conditions. Recent studies have highlighted numerous environmental factors capable of compromising epithelial integrity and disrupting its barrier function, including allergens with protease activity. Allergenic proteases from various sources, such as dust mites, pollen, fungi, and kitchen cockroaches, have been identified and characterized. Studies have shown the significant role these allergens play in compromising the integrity of the respiratory epithelium and triggering allergic responses. They can activate specific receptors, inducing inflammation and disrupting the epithelium’s barrier function. For example, proteases from dust mites cleave junctional proteins, promoting allergen transport and triggering the release of proinflammatory cytokines. The same effect is observed with pollen, fungi, and kitchen cockroaches. The proteolytic activity of allergens contributes to sensitization and the progression of allergic diseases. Understanding these mechanisms can guide the development of effective therapeutic strategies for preventing and treating these conditions.

Variations In The Genotypic And Phenotypic Characteristics Of Methicillin-Resistant Staphylococcus Aureus (Mrsa) From Students Attending Poultry Farms In Umuahia, Abia State, Nigeria

Staphylococcus aureus causes significant epidemiologic and therapeutic challenges with various skin and soft tissue infections, the main forms of disease manifestation. The public health importance of this organism has been heightened by the emergence and spread of species that are resistant to treatment usually referred to as methicillin-resistant S. aureus (MRSA). This study was carried out to detect mecA and mecC genes in phenotypically determined MRSA isolates. Nasal swab samples of the subjects were cultured on mannitol salt agar and the isolates were identified as S. aureus using a combined morphological and biochemical characteristic. Antibiotic susceptibility profile was performed using the disk diffusion susceptibility method whilst phenotypic detection of MRSA isolates was by Cefoxitin disk diffusion method as per CLSI guidelines. Genomic DNA was extracted from the isolates using commercial kits. The extracted DNA was subjected to multiplex PCR to amplify the 163-bp and 188-bp fragment of the mecA and mecC genes respectively in a Pielter thermal cycler. The susceptibility pattern of MRSA isolates showed that the organisms were highly resistant to Augmentin 29 (93.5%), ceftazidime 18 (58.1%), Streptomycin 19 (76%) whilst high levels of susceptibility were seen for Ofloxacin 27 (87.1%), Levofloxacin 28 (90.3%), and Gentamicin 24 (77.4%). The antibiotic resistance profiles in MRSA isolates were recorded as follows: ciprofloxacin 6 (16.2%), Augmentin 32 (86.4%), erythromycin 13 (35.1%), Ceftazidime 22 (59.4%). Of the 10 MRSA isolates that were subjected to PCR, one isolate was found to harbor the 188-bp of mecC gene whilst mecA was absent from the screened isolates. The detection of mecC MRSA in the present study highlights the diagnostic importance of screening for mecC in mecA negative MRSA. We suggest that surveillance for MRSA should include screening for mecC gene where mecA is not detected in resistant isolates. Stamford Journal of Microbiology, 2023. Vol. 13, Issue 1, p. 6-10

Detection of Staphylococci from nasal samples from healthy and sick dogs in Ho Chi Minh City, Vietnam

Staphylococci are one of the most commonly found opportunistic bacteria in animals and human. The objective of this study was to determine the prevalence of Staphylococcus spp. isolated from healthy and sick dogs visiting veterinary clinics in Ho Chi Minh city, Vietnam from January 2022 to December 2022. A total of 123 nasal swab samples were collected, including 40 samples from healthy dogs and 83 samples from dogs with respiratory symptoms. Staphylococcus spp. were isolated from 47.5% of healthy animals and 60.24% of dogs showing respiratory symptoms. The study showed that isolation rates from confined, semi-confined and free-ranging dogs were 75.86%, 54.84% and 40.63%, respectively. Furthermore, the prevalence was higher in dogs over one year old compared to younger dogs (64.10% and 42.22%, respectively). Several subspecies of Staphylococci, including S. aureus, S. pseudintermedius and S. epidermidis were identified, in which S. pseudintermedius accounted for the highest proportion (48.28%). The prevalence of S. pseudintermedius also varied across different age groups. Coagulase activity of the isolated Staphylococcus strains was also determined and indicated that coagulase-positive Staphylococci constituted 80.46% of the isolates. This study represents the first report on the prevalence of Staphylococci in dogs in Vietnam and reemphasizes the zoonotic significance of Staphylococcus at the interface between dogs and humans.

Intranasal immunization with the recombinant measles virus encoding the spike protein of SARS-CoV-2 confers protective immunity against COVID-19 in hamsters

BackgroundAs the nasal mucosa is the initial site of infection for COVID-19, intranasal vaccines are more favorable than conventional vaccines. In recent clinical studies, intranasal immunization has been shown to generate higher neutralizing antibodies; however, there is a lack of evidence on sterilizing immunity in the upper airway. Previously, we developed a recombinant measles virus encoding the spike protein of SARS-CoV-2 (rMeV-S), eliciting humoral and cellular immune responses against SARS-CoV-2. ObjectivesIn this study, we aim to provide an experiment on nasal vaccines focusing on a measles virus platform as well as injection routes. Study designRecombinant measles viruses expressing rMeV-S were prepared, and 5 × 105 PFUs of rMeV-S were administered to Syrian golden hamsters via intramuscular or intranasal injection. Subsequently, the hamsters were challenged with inoculations of 1 × 105 PFUs of SARS-CoV-2 and euthanized 4 days post-infection. Neutralizing antibodies and RBD-specific IgG in the serum and RBD-specific IgA in the bronchoalveolar lavage fluid (BALF) were measured, and SARS-CoV-2 clearance capacity was determined via quantitative reverse-transcription PCR (qRT-PCR) analysis and viral titer measurement in the upper respiratory tract and lungs. Immunohistochemistry and histopathological examinations of lung samples from experimental hamsters were conducted. ResultsThe intranasal immunization of rMeV-S elicits protective immune responses and alleviates virus-induced pathophysiology, such as body weight reduction and lung weight increase in hamsters. Furthermore, lung immunohistochemistry demonstrated that intranasal rMeV-S immunization induces effective SARS-CoV-2 clearance that correlates with viral RNA content, as determined by qRT-PCR, in the lung and nasal wash samples, SARS-CoV-2 viral titers in lung, nasal wash, BALF samples, serum RBD-specific IgG concentration, and RBD-specific IgA concentration in the BALF. ConclusionAn intranasal vaccine based on the measles virus platform is a promising strategy owing to the typical route of infection of the virus, the ease of administration of the vaccine, and the strong immune response it elicits.

Development of a one-step multiplex (RT)-PCR for simultaneous detection of virus-induced respiratory disease complex in dogs in Vietnam

Canine infectious respiratory disease (CIRD) viruses, particularly canine distemper virus (CDV), canine adenovirus type 2 (CAV-2), and canine parainfluenza virus (CPIV), are the primary agents responsible for respiratory diseases in dogs. A dog can be infected with a single or multiple viruses with similar clinical signs. Although CIRD is globally prevalent in dogs, investigation into the causative viruses in Vietnam remains limited. This study aims to identify the presence of CIRD virus(es) in dogs via molecular detection. Three primer sets were newly designed and applied into (RT)-PCR reaction to detect viral genes of CDV, CAV-2, and CPIV in a commercial vaccine (Vanguard® Plus 5/L, Zoetis, USA). Both simplex and multiplex (RT)-PCR reactions using the three primer sets could detect the presence of CAV-2, CDV, and CPIV in the vaccine sample. Subsequently, the applicability of the one-step multiplex (RT)-PCR was demonstrated to test for 27 clinical nasal swab samples collected from dogs suspected of having CIRD. The results showed that our (RT)-PCR could detect CIRD virus(es) in all tested clinical samples. PCR amplicons for each representative CAV-2, CDV, and CPIV were selected for sequencing and showed high genetic similarity to respective field viruses. In conclusion, this study successfully developed a one-step multiplex (RT)-PCR reaction to detect and differentiate causative viruses of CIRD in dogs.

Electrochemical microfluidic paper-based analytical device for label-free detection of SARS-CoV-2 antigen by LDH redox probe

In the offered study, the proposed sensor combined the innovative disposable microfluidic paper-based immunosensor and cost-effective plant-based anti-SARS-CoV-2 monoclonal antibody CR3022, expressed in Nicotiana benthamiana. An electrochemical microfluidic paper-based analytical device (µPAD) was introduced for quantitative detection of the SARS-CoV-2 antigen employing electrocatalytic activity of the Ni Fe layered double hydroxide (NiFe LDH). Its electrocatalytic activity asthe platform of proposed the analytical device enhanced the signal output via redox-recycling of the species the ferri/ferrocyanide [Fe(CN)6]3-/4- in solution and is applied to µPAD response signal. Layered NiFe double hydroxide (LDH) nanosheets with a suitable redox potential were prepared by incorporating Fe into the Ni-based LDH. With the help of Fe, the charge-transfer kinetics for the reduction of Ni3+ to Ni2+ was improved and the formation of unwanted Ni components with higher oxidation state was suppressed. The incorporated Fe as the electron transfer mediator enhanced the process of Ni(OH)2/NiOOH redox cycle. Under the optimum conditions, the dependency of impedance signal and SARS-CoV-2 concentration showed a linear region from 10 fg/mL-5 ng/mL with a detection limit of 0.23 fg/mL. This Paper-based immunosensor device also showed long stability and good reproducibility, which can be used for the quantitative assay of the SARS-CoV-2. The results of nasal samples analysis revealed the applicability of the resulting biosensor.