The purpose of this randomized study will be to determine whether topical probiotic sinus irrigations are more effective compared to saline sinus irrigation controls in the treatment of active CRS in patients who have had prior sinus surgery based on subjective and objective outcome measures.

CRS is a common clinical entity with estimated prevalence ranging from 14-16% in the community. The most commonly implicated pathogenic bacteria in recalcitrant patients are Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). In recent years, there has been an increasing focus on the commensal sinonasal microbiome and its role in the development of a functional immune system. It has been theorized that infections in CRS may be related to a decrease in diversity of the commensal microbiome and an increase in these pathogenic bacteria. The concept behind the therapeutic potential of topical probiotics is that they outcompete pathogenic bacteria via a variety of mechanisms, including creating suboptimal environmental conditions, competing for cell surface receptors and thus limiting pathogen adherence, and producing antibacterial metabolites. In doing so, topical probiotics restore the commensal microbiome.

For this study, after being informed about the study and potential risks, all patients meeting eligibility criteria and giving written informed consent will be randomized in a double blind manner (participant and investigator) in a 1:1 ratio to Lactobacillus sakei or saline nasal irrigation, twice a day for 14 days.

Patient assessments will occur before treatments begin, immediately after the completion of nasal irrigations, and 6 weeks after initial enrollment. Assessments will be based on patient history, endoscopic exams, culture swab of the sinuses (bacterial burden and number of taxa, SNOT-22 survey, and a visual analog scale to record pain scores.

Inclusion Criteria:

1. Male and female patients 18 years of age or older.
2. Patients diagnosed with acute exacerbation of CRS, defined by worsening of 1 or more sinonasal symptoms (nasal obstruction/congestion, nasal discharge, facial pain/pressure, reduced sense of smell) and inflammatory and/or infectious changes on sinus endoscopy.
3. Patients that have undergone functional endoscopic sinus surgery > 12 months prior to enrollment as documented in the patients electronic medical record, with patent sinuses deemed suitable for trial on investigator's discretion.
4. Patients must be willing to follow study related procedures for the duration of the study.
5. Patients must understand the purpose and procedures and be willing to sign the study informed consent document.
6. All adult men and women with active CRS will be considered for participation in this study without regard to race, gender, or socioeconomic status.

Exclusion Criteria:

1. Patients who are taking topical antibiotic irrigations and are unwilling to stop them.
2. Patients who are unable to complete self-administered questionnaires because of cognitive impairment, language barrier, or severe medical conditions.
3. Patients who have a terminal illness (malignancy), immunocompromised (medication-related immunosuppression, immunodeficiency disorder) or systemic disease (granulomatosis polyangiitis or other autoimmune disease with sinonasal manifestations, cystic fibrosis), or recent head/sinonasal trauma that may predispose to infectious complications.
4. Patients who have severe or emergent complications from CRS or presence of a sinus tumor.
5. Female patients who are pregnant or breastfeeding. The patient will be asked if she is pregnant or has any chance of being pregnant. In either case, the patient will be excluded. Note in our consent form this is also addressed (excerpt below).
6. Patients who are taking oral corticosteroids or who have taken oral antibiotics in the previous 2 weeks or on oral corticosteroids.
7. Patients who have upper respiratory infection-type symptoms at time of enrollment, e.g., fevers/chills, sneezing, runny nose, sore throat, coughing. Patients can be eligible for enrollment once symptoms have fully resolved if all other inclusion/exclusion criteria are met.

At the beginning of the study patients will be provided enough study product to complete 2 nasal sinus irrigations/day for a period of 14 days. There will be 1 packet for each nasal irrigation procedure (a total of 28 vials for 2 weeks). The packets will be distributed by the University's Investigational Drug Service (IDS) and will be labeled in a way that neither the patient nor the investigator will know the contents of the packet. Only IDS personnel will have the product/patient code link.