Rhinitis is a type of upper respiratory infection with a common nasal pathology especially in Southeast Asia, which is characterized by the presence of one or more of the following symptoms: itchy nose, sneezing, runny nose, and nasal congestion. Other symptoms occasionally experienced include headache, excessive pain reaction, cough, fever. Rhinitis can be idiopathic or due to a variety of causes, including allergens, medications, endocrine/metabolic, infectious, inflammatory, and abnormal nasal structures. The treatment of acute rhinosinusitis and allergic rhinitis in hospitals is currently carried out according to the general professional guidance of the Vietnam Ministry of Health. Most patients are prescribed corticosteroids, antihistamines, and antibiotics for immediate decongestion and anti-inflammatory effects. Current concerns about antimicrobial resistance (AMR) as well as side effects of corticosteroids and antihistamines have led to an urgent need for a naturebased next generation therapeutic approach that is safe, effective and helps in addressing the issues of AMR. The goal of this interventional study is to evaluate the safety and efficacy of postbiotic nasal spray using inert bioparticles of Bacillus subtilis DSM32444 in treatment of acute rhinosinusitis; and to compare the efficacy against Neomycin/Dexamethasone//Xylometazoline administered as a nasal spray as an adjunct to Amoxicillin/Clavulanate standard treatment in patients with acute rhinosinusitis.

Patients with acute rhinosinusitis who give consent to participate in the study will be randomly assigned in a 1:1 ratio to one of two groups using postbiotic of Bacillus subtilis DSM32444 nasal spray ("Sperovid") or Neomycin/ Dexamethasone nasal spray for a period of 10 days. Investigators will compare whether the nasal spray using postbiotic Bacillus subtilis DSM32444 has similar efficacy as compared to Neomycin/Dexamethasone/Xylometazoline nasal spray as an adjuvant therapy along with the standard Amoxicillin/Clavulanate regimen in patients with acute rhinosinusitis based on time to improvement of rhinosinusitis symptoms.

Rhinitis is a type of upper respiratory infection with a common nasal pathology especially in Southeast Asia, which is characterized by the presence of one or more of the following symptoms: itchy nose, sneezing, runny nose, and nasal congestion. Other symptoms occasionally experienced include headache, excessive pain reaction, cough, fever. Rhinitis can be idiopathic or due to a variety of causes, including allergens, medications, endocrine/metabolic, infectious, inflammatory, and abnormal nasal structures. Rhinosinusitis in general is not a dangerous pathological condition, however the frequency of the disease is relatively high with statistics showing that all people experience it at least once in their lives. Common rhinosinusitis symptoms include severe facial pains and difficulties in breathing. Hence, most patients are prescribed corticosteroids, antihistamines, and antibiotics for immediate decongestion and anti-inflammatory effects. A common treatment regime for patients with rhinosinusitis in Vietnam includes a combination of steroids and antibiotics (Neomycin/Dexamethasone/Xylometazoline) administered as a nasal spray, in adjunct with Amoxicillin/clavulanate 875/125 mg taken orally every 12 hours. Dexamethasone sodium phosphate is fluoromethyl prednisolone, a synthetic glucocorticoid. Glucocorticoids work by binding to receptors in cells, translocating into the cell nucleus, and there, affecting certain translated genes.

Glucocorticoids also have some direct effects, possibly through receptormediated attachment. Dexamethasone has the main effects of glucocorticoids as anti-inflammatory, antiallergic and immunosuppressant. In terms of anti-inflammatory activity, dexamethasone is 30 times stronger than hydrocortisone, 7 times stronger than prednisone. Neomycin sulfate is an antibiotic belonging to the group of aminoglycosides that have a bactericidal mechanism due to inhibition of bacterial protein biosynthesis. Bacteria sensitive to neomycin include: Staphylococcus aureus, Escherichia coli, Haemophilus influenzae, Klebsiella, Enterobacter of all kinds, Neisseria of all kinds. The antibiotic is used to prevent bacterial infection and is formulated for use together with glucocorticoids for a fast relief of rhinosinusitis symptoms. The duration of treatment for patients is about 10 days depending on the severity of the disease. During the treatment period, a change in the systemic antibiotic regimen is necessary if the observations after 3 to 5 days of treatment do not show signs of a satisfactory response. Current concerns about antimicrobial resistance (AMR) as well as the documented side effects of corticosteroid and antihistamine have led to an urgent need for a nature-based next generation therapeutic approach that is safe, effective and helps in addressing the AMR problem. Preclinical studies of inactivated Bacillus subtilis strain DSM32444 conducted by collaborating UK universities and laboratories have shown potential therapeutic benefits with anti-inflammatory mechanisms that may be useful in other viral infections of the respiratory tract. The reason for using an inactivated spore is because various publications have identified risks of inhalation of high doses of live bacteria in the respiratory tract and lungs. DSM32444 also carries GRAS status for human use. An accredited, cGLP, repeat-dose toxicology study also confirmed complete safety in rodent models after high doses of treatment. The investigators think there is a likelihood to apply this postbiotic technology to mitigate the overuse of antibiotics, corticosteroids, and antihistamines. The aim of this study is to evaluate the safety of a nasal spray using a postbiotic preparation of Bacillus subtilis DSM32444 and that is a sterile inert bioparticle, as well as the efficacy in treating acute rhinosinusitis as compared to Neomycin/ Dexamethasone/ Xylometazoline administered as a nasal spray.

• Study population: Sample size is 60 volunteered patients with acute rhinosinusitis.
• Description of Sites: the study is carried out at Thai Binh University of Medicine and Pharmacy and Thai Binh University of Medicine and Pharmacy Hospital.
• Description of Study intervention:

This phase is a randomized, parallel controlled, open-label, product-controlled study (Neomycin/Dexamethasone/Xylometazoline nasal spray). The randomization is carried out according to the 4-block strategy using envelopes with predetermined random codes. Study subjects will be given codes in turn sealed in sequentially numbered envelopes. The research product is formulated as an open label due to the different shape of the product. Participants in the study who are patients with rhinosinusitis (viral, bacterial or suspected bacterial) are randomly assigned in a 1:1 ratio to one of two groups using Sperovid or Neomycin/Dexamethasone/Xylometazoline nasal spray for a period of 10 days. The research product (Sperovid or Neomycin/Dexamethasone/Xylometazoline nasal spray) is sprayed 2-3 times daily, sprayed on both sides of the nose, each time 1-2 sprays corresponding to 0.2 ml/spray. Both groups of patients received amoxicillin/clavulanate 875/125 mg orally every 12 hours a day with a 10-day course of treatment. Daily nasopharyngeal symptom assessment (TSS) is performed using a diary from Day 1 to Day 10 (end of regime). The response assessment is done on Day 5 (±1) and the decision to continue or change the treatment regimen will be made by the research physician at this time.

• The study data after collection will be analyzed statistically using SAS 9.4. The normal distribution of statistical samples will be evaluated by the Kolmogorov-Smirnov-Lilliefors test, the uniformity of variance will be verified by Levene's test. The continuous variables will be analyzed using a two-dimensional variance test or covariance analysis (ANOVA/ANCOVA) in the case of a normal distribution and using the ANOVA non-parametric Kruskal-Wallis test in the case of a non-standard distribution. Repeatable measurement analyses will be used where appropriate. Differences between treatment groups in terms of duration of major symptoms of acute respiratory infection and average time to resolution will be assessed using the Student's t-test or the Mann-Whitney test. Chi-Square (or Fisher's exact test) will be used to evaluate the difference between the ratios. Analysis of classification data is carried out using the Cochran-Mantel- Haenszel test. In the absence of further note, the continuous variables are expressed by the mean ± standard deviation. The Cox analysis model and log-rank testing will be used to compare variables of the time type leading up to an event.
• Expected outcomes: (1) The nasal spray using a postbiotic preparation of Bacillus subtilis DSM32444 and that is a sterile inert bioparticle ("Sperovid") is safe and well tolerated among healthy volunteers, and (2) The inactivated Bacillus subtilis DSM32444 ("Sperovid") has similar efficacy as compared to Neomycin/Dexamethasone as an adjuvant therapy along with the standard Amoxicillin/Clavulanate regimen in patients with acute rhinosinusitis based on time to improvement of rhinosinusitis symptoms.

Inclusion Criteria:

• Confirmed rhinosinusitis patients (according to Vietnam's MOH guidelines for diagnosis of rhinosinusitis), ≥18 years of age, at the time of signing the informed consent.
• Must be in generally good health, except rhinosinusitis
• Patients who are able to use an e-Diary or Paper Diary during the study to report their health status
• Patients capable of giving a signed informed consent form (ICF)

Exclusion Criteria:

• Presence of any nasal mucosal erosion, nasal ulceration, or nasal septal perforation (Grade 1b - 4)
• Other nasal disease(s) likely to affect deposition of intranasal medication, such as sinusitis, rhinitis medicamentosa, clinically significant polyposis, or nasal structural abnormalities.
• Nasal surgery or sinus surgery within the previous year
• Chronic sinusitis - more than 3 episodes per year
• Asthma (with the exception of mild, intermittent asthma). Subjects with mild, intermittent asthma who only require short-acting inhaled bronchodilators (not more often than twice per week) and who do not have nocturnal awakening as a result of asthma are eligible for enrolment.
• Planned travel outside of the study area during the study period.
• Use of any investigational drug within 30 days prior to Day screening. No investigational products are permitted for use during the conduct of this study.
• Existence of any medical condition, which in the opinion of the investigator, might significantly affect the subject's ability to complete this trial; or their safety in this trial.