The upregulation of K+ and HCN channels in developing spiral ganglion neurons is mediated by cochlear inner hair cells.

Spiral ganglion neurons (SGNs) are primary sensory afferent neurons that relay acoustic information from the cochlear inner hair cells (IHCs) to the brainstem. The response properties of different SGNs diverge to represent a wide range of sound intensities in an action-potential code. This biophysical heterogeneity is established during pre-hearing stages of development, a time when IHCs fire spontaneous Ca2+ action potentials that drive glutamate release from their ribbon synapses onto the SGN terminals. The role of spontaneous IHC activity in the refinement of SGN characteristics is still largely unknown. Using pre-hearing otoferlin knockout mice (Otof-/-), in which Ca2+-dependent exocytosis in IHCs is abolished, we found that developing SGNs fail to upregulate low-voltage-activated K+-channels and hyperpolarisation-activated cyclic-nucleotide-gated channels. This delayed maturation resulted in hyperexcitable SGNs with immature firing characteristics. We have also shown that SGNs that synapse with the pillar side of the IHCs selectively express a resurgent K+ current, highlighting a novel biophysical marker for these neurons. RNA-sequencing showed that several K+ channels are downregulated in Otof-/- mice, further supporting the electrophysiological recordings. Our data demonstrate that spontaneous Ca2+-dependent activity in pre-hearing IHCs regulates some of the key biophysical and molecular features of the developing SGNs. KEY POINTS: Ca2+-dependent exocytosis in inner hair cells (IHCs) is otoferlin-dependent as early as postnatal day 1. A lack of otoferlin in IHCs affects potassium channel expression in SGNs. The absence of otoferlin is associated with SGN hyperexcitability. We propose that type I spiral ganglion neuron functional maturation depends on IHC exocytosis.

Epidemiology of Clostridioides difficile infection at one hospital 10 years after an outbreak of the epidemic C. difficile strain BI/027: changing strain prevalence, antimicrobial susceptibilities, and patient antibiotic exposures.

In contrast to the epidemiology 10 years earlier at our hospital when the epidemic restriction endonuclease analysis (REA) group strain BI accounted for 72% of Clostridioides difficile isolates recovered from first-episode C. difficile infection (CDI) cases, BI represented 19% of first-episode CDI isolates in 2013-2015. Two additional REA group strains accounted for 31% of isolates (Y, 16%; DH, 12%). High-level resistance to fluoroquinolones and azithromycin was more common among BI isolates than among DH, Y, and non-BI/DH/Y isolates. Multivariable analysis revealed that BI cases were 2.47 times more likely to be associated with fluoroquinolone exposure compared to non-BI cases (95% confidence interval [CI]: 1.12-5.46). In addition, the odds of developing a CDI after third- or fourth-generation cephalosporin exposure was 2.83 times for DH cases than for non-DH cases (95% CI: 1.06-7.54). Fluoroquinolone use in the hospital decreased from 2005 to 2015 from a peak of 113 to a low of 56 antimicrobial days/1,000 patient days. In contrast, cephalosporin use increased from 42 to 81 antimicrobial days/1,000 patient days. These changes correlated with a decrease in geometric mean MIC for ciprofloxacin (61.03 to 42.65 mg/L, P = 0.02) and an increase in geometric mean MIC for ceftriaxone (40.87 to 86.14 mg/L, P < 0.01) among BI isolates. The BI strain remained resistant to fluoroquinolones, but an overall decrease in fluoroquinolone use and increase in cephalosporin use were associated with a decrease in the prevalence of BI, an increased diversity of C. difficile strain types, and the emergence of strains DH and Y.

Advances in Extraction, Structure, and Physiochemical Properties of Sorghum Kafirin for Biomaterial Applications: A Review.

Kafirin is an endosperm-specific hydrophobic protein found in sorghum grain and the waste by-product from sorghum biorefineries known as sorghum dried distillers' grain with solubles (DDGS). Because of kafirin's poor nutritional profile (negative nitrogen balance, slow digestibility, and lack of some essential amino acids), its direct human use as a food is restricted. Nevertheless, increased focus on biofuel production from sorghum grain has triggered a new wave of research to use sorghum DDGS kafirin as a food-grade protein for biomaterials with diverse applications. These applications result from kafirin's unique chemical nature: high hydrophobicity, evaporation-induced self-assembling capacity, elongated conformation, water insolubility, and low digestibility. Aqueous alcohol mixtures have been widely used for the extraction of kafirin. The composition, structure, extraction methodologies, and physiochemical properties of kafirin, emphasising its biomaterial functionality, are discussed in detail in this review. The literature survey reveals an in-depth understanding of extraction methodologies and their impact on structure functionality, which could assist in formulating materials of kafirin at a commercial scale. Ongoing research continues to explore the potential of kafirin and optimise its utilisation as a functional biomaterial, highlighting its valuable structural and physicochemical properties. Further studies should focus on covering gaps in the research as some of the current structural understanding comes from data on zein protein from maize.

Pleiotropic brain function of whirlin identified by a novel mutation.

Despite some evidence indicating diverse roles of whirlin in neurons, the functional corollary of whirlin gene function and behavior has not been investigated or broadly characterized. A single nucleotide variant was identified from our recessive ENU-mutagenesis screen at a donor-splice site in whirlin, a protein critical for proper sensorineural hearing function. The mutation (head-bob, hb) led to partial intron-retention causing a frameshift and introducing a premature termination codon. Mutant mice had a head-bobbing phenotype and significant hyperactivity across several phenotyping tests. Lack of complementation of head-bob with whirler mutant mice confirmed the head-bob mutation as functionally distinct with compound mutants having a mild-moderate hearing defect. Utilizing transgenics, we demonstrate rescue of the hyperactive phenotype and combined with the expression profiling data conclude whirlin plays an essential role in activity-related behaviors. These results highlight a pleiotropic role of whirlin within the brain and implicate alternative, central mediated pathways in its function.

Sorghum Grain Polyphenolic Extracts Demonstrate Neuroprotective Effects Related to Alzheimer's Disease in Cellular Assays.

Sorghum grain contains high levels and a diverse profile of polyphenols (PPs), which are antioxidants known to reduce oxidative stress when consumed in the diet. Oxidative stress leading to amyloid-ß (Aß) aggregation, neurotoxicity, and mitochondrial dysfunction is implicated in the pathogenesis of Alzheimer's disease (AD). Thus, PPs have gained attention as possible therapeutic agents for combating AD. This study aimed to (a) quantify the phenolic compounds (PP) and antioxidant capacities in extracts from six different varieties of sorghum grain and (b) investigate whether these PP extracts exhibit any protective effects on human neuroblastoma (BE(2)-M17) cells against Aß- and tau-induced toxicity, Aß aggregation, mitochondrial dysfunction, and reactive oxygen species (ROS) induced by Aß and tert-butyl hydroperoxide (TBHP). PP and antioxidant capacity were quantified using chemical assays. Aß- and tau-induced toxicity was determined using the 3-(4,5-dimenthylthiazol-2-yl)-2,5-dimethyltetrazolium bromide (MTS) assay. The thioflavin T (Th-T) assay assessed anti-Aß aggregation. The dichlorodihydrofluorescein diacetate (DCFDA) assay determined the levels of general ROS and the MitoSOX assay determined the levels of mitochondrial superoxide. Sorghum varieties Shawaya short black-1 and IS1311C possessed the highest levels of total phenolics, total flavonoids, and antioxidant capacity, and sorghum varieties differed significantly in their profile of individual PPs. All extracts significantly increased cell viability compared to the control (minus extract). Variety QL33 (at 2000 µg sorghum flour equivalents/mL) showed the strongest protective effect with a 28% reduction in Aß-toxicity cell death. The extracts of all sorghum varieties significantly reduced Aß aggregation. All extracts except that from variety B923296 demonstrated a significant (p ≤ 0.05) downregulation of Aß-induced and TBHP-induced ROS and mitochondrial superoxide relative to the control (minus extract) in a dose- and variety-dependent manner. We have demonstrated for the first time that sorghum polyphenolic extracts show promising neuroprotective effects against AD, which indicates the potential of sorghum foods to exert a similar beneficial property in the human diet. However, further analysis in other cellular models and in vivo is needed to confirm these effects.

Vitamin K content of Australian-grown horticultural commodities.

Vitamin K is a multi-function vitamin that has emerging roles in bone, brain and vascular health. Vitamin K composition data remain limited globally and Australia has lacked nationally representative data for vitamin K1 (phylloquinone) in horticultural commodities. Primary samples (n = 927) of 90 Australian-grown fruit, vegetable and nut commodities were purchased in three Australian cities. We measured vitamin K1/phylloquinone in duplicate in 95 composite samples using liquid chromatography with electrospray ionisation-tandem mass spectrometry. The greatest mean concentrations of vitamin K1/phylloquinone were found in kale (565 µg/100 g), baby spinach (255 µg/100 g) and Brussels sprouts (195 µg/100 g). The data contribute to the global collection of vitamin K food composition data. They add to the evidence that vitamin K1/phylloquinone concentrations vary markedly between geographic regions, supporting development of region-specific datasets for national food composition databases that do not yet contain data for vitamin K. Such data are needed globally.

Management and Outcomes of Patients at a Specialty Clinic for Clostridioides difficile Infection.

Vancomycin and fidaxomicin taper regimens were the most common treatment strategies employed but nearly half of patients (40/83) referred to our Clostridioides difficile infection (CDI) clinic did not require further treatment. The overall 60-day CDI recurrence rate was 16.9% (11/65). CDI management at a dedicated clinic may improve clinical outcomes.

BAI1 localizes AMPA receptors at the cochlear afferent post-synaptic density and is essential for hearing.

Type I spiral ganglion neurons (SGNs) convey sound information to the central auditory pathway by forming synapses with inner hair cells (IHCs) in the mammalian cochlea. The molecular mechanisms regulating the formation of the post-synaptic density (PSD) in the SGN afferent terminals are still unclear. Here, we demonstrate that brain-specific angiogenesis inhibitor 1 (BAI1) is required for the clustering of AMPA receptors GluR2-4 (glutamate receptors 2-4) at the PSD. Adult Bai1-deficient mice have functional IHCs but fail to transmit information to the SGNs, leading to highly raised hearing thresholds. Despite the almost complete absence of AMPA receptor subunits, the SGN fibers innervating the IHCs do not degenerate. Furthermore, we show that AMPA receptors are still expressed in the cochlea of Bai1-deficient mice, highlighting a role for BAI1 in trafficking or anchoring GluR2-4 to the PSDs. These findings identify molecular and functional mechanisms required for sound encoding at cochlear ribbon synapses.

Characteristics and outcomes of Clostridioides difficile infection after a change in the diagnostic testing algorithm.

BACKGROUND: Polymerase chain reaction (PCR) testing for the detection of C. difficile is a highly sensitive test. Some clinical laboratories have included a 2-step testing algorithm utilizing PCR plus toxin enzyme immunoassays (EIAs) to increase specificity. OBJECTIVE: To determine the risk factors and outcomes of C. difficile PCR-positive/toxin-positive encounters compared to PCR-positive/toxin-negative encounters. DESIGN: Retrospective study. SETTING: A Veterans' Affairs hospital. METHODS: A retrospective case-control study of patient encounters with a positive C. difficile test by PCR and either a toxin EIA-positive assay (ie, cases) or toxin EIA-negative assay (ie, controls). Clinically relevant exposures and risk factors were determined to assess CDI recurrence at 30 days. Available encounter stool specimens were cultured for C. difficile and were subjected to restriction endonuclease analysis (REA) strain typing. RESULTS: Among 130 C. difficile PCR-positive patient encounters, 80 (61.5%) were toxin EIA negative and 50 (38.5%) were toxin EIA positive. Encounters that were toxin positive were more frequently treated (96.0%) compared to toxin-negative encounters (71.3%; P < .01). A multivariable logistic regression model revealed that toxin-negative encounters were less likely to suffer a recurrent CDI episode within 30 days (odds ratio [OR], 0.20, 95% confidence interval [CI], 0.05-0.83). Additionally, a higher C. difficile PCR cycle threshold predicted a lower risk of CDI recurrence at 30 days. (OR, 0.82; 95% CI, 0.68-0.98). During the study period, the REA group Y strain accounted for most toxin-negative encounters (32.5%; P = .05), whereas REA group BI strain accounted for most toxin-positive encounters (24.3%; P = .02). CONCLUSIONS: A testing strategy of PCR plus toxin EIA helped predict recurrent CDI.

Recommendations to Improve Quality of Probiotic Systematic Reviews With Meta-Analyses.

Importance: Systematic reviews and meta-analyses often report conflicting results when assessing evidence for probiotic efficacy, partially because of the lack of understanding of the unique features of probiotic trials. As a consequence, clinical decisions on the use of probiotics have been confusing. Objective: To provide recommendations to improve the quality and consistency of systematic reviews with meta-analyses on probiotics, so evidence-based clinical decisions can be made with more clarity. Evidence Review: For this consensus statement, an updated literature review was conducted (January 1, 2020, to June 30, 2022) to supplement a previously published 2018 literature search to identify areas where probiotic systematic reviews with meta-analyses might be improved. An expert panel of 21 scientists and physicians with experience on writing and reviewing probiotic reviews and meta-analyses was convened and used a modified Delphi method to develop recommendations for future probiotic reviews. Findings: A total of 206 systematic reviews with meta-analysis components on probiotics were screened and representative examples discussed to determine areas for improvement. The expert panel initially identified 36 items that were inconsistently reported or were considered important to consider in probiotic meta-analyses. Of these, a consensus was reached for 9 recommendations to improve the quality of future probiotic meta-analyses. Conclusions and Relevance: In this study, the expert panel reached a consensus on 9 recommendations that should promote improved reporting of probiotic systematic reviews with meta-analyses and, thereby, assist in clinical decisions regarding the use of probiotics.

Fecal Microbiota, Live-jslm for the Prevention of Recurrent Clostridioides difficile Infection : Subgroup Analysis of PUNCH CD2 and PUNCH CD3.

GOALS: To assess fecal microbiota, live-jslm (REBYOTA, abbreviated as RBL, formerly RBX2660) efficacy and safety in participants grouped by recurrent Clostridioides difficile infection (rCDI) risk factors and treatment-related variables. BACKGROUND: RBL is the first microbiota-based live biotherapeutic approved by the US Food and Drug Administration for the prevention of rCDI in adults after antibiotic treatment for rCDI. STUDY: Treatment success rates across subgroups for PUNCH CD3 (NCT03244644) were estimated using a Bayesian hierarchical model, borrowing data from PUNCH CD2 (NCT02299570). Treatment-emergent adverse events were summarized for the double-blind treatment period within 8 weeks. RESULTS: Treatment differences between RBL and placebo at 8 weeks were similar to the total population for most subgroups. Treatment effect sizes were similar between CDI tests, higher for oral vancomycin courses >14 days versus ≤14 days and higher for antibiotic washout periods of 3 days versus ≤2 days. The largest reductions in the rate of rCDI with RBL versus placebo were observed for participants with a 3-day CDI antibiotic washout period and participants with ≥4 previous CDI episodes. Most RBL-treated participants experienced TEAEs that were mild or moderate in severity and related to preexisting conditions. CONCLUSION: This analysis provides further evidence of RBL efficacy and safety across subgroups, including those at high risk for rCDI.

Efficacy of bezlotoxumab to prevent recurrent Clostridioides difficile infection (CDI) in patients with multiple prior recurrent CDI.

Among 23 patients with multiply recurrent Clostridioides difficile infection (mrCDI) who received bezlotoxumab at the end of antibiotic treatment a sustained clinical response of 91 % at 30 days and 78 % at 90 days was achieved. Bezlotoxumab administered at the end of antibiotic treatment was effective in patients with mrCDI.

Implementing structured pathology reporting protocol for non-melanocytic skin cancers: practical considerations.

Non-melanocytic skin cancers (NMSCs) account for five times the incidence of all other cancers combined and cost US $6 billion annually. These are the most frequent specimens encountered in community pathology practice in many Western countries. Lack of standardised structured pathology reporting protocols (SPRPs) can result in omission of critical information or miscommunication leading to suboptimal patient management. The lack of standardised data has significant downstream public health implications, including insufficient data for reliable development of prognostic tools and health-economy planning. The Royal College of Pathologists of Australasia has developed an NMSC SPRP. A multidisciplinary expert committee including pathologists, surgeons, dermatologists, and radiation and medical oncologists from high volume cancer centres was convened. A systematic literature review was performed to identify evidence for including elements as mandatory standards or best practice guidelines. The SPRP and accompanying commentary of evidence, definitions and criteria was peer reviewed by external stakeholders. Finally, the protocol was revised following feedback and trialled in multiple centres prior to implementation. Some parameters utilised clinically for determining management and prognosis including tumour depth, lymphovascular invasion or distance to the margins lack high level evidence in NMSC. Dermatologists, surgeons, and radiation oncologists welcomed the SPRP. Pathologists indicated that the variety of NMSC specimens ranging from curettes to radical resections as well as significant differences in the biological behaviour of different tumours covered by the NMSC umbrella made use of a single protocol difficult. The feedback included that using a SPRP for low risk NMSC was neither clinically justified nor compensated adequately by the Australian Medicare Reimbursement Schedule. Following stakeholder feedback, the SPRP implementation was restricted to excision specimens of head and neck NMSC; and low-risk NMSC, such as superficial basal cell carcinoma, were excluded. Implementing NMSC SPRP fulfils an unmet clinical need. Unlike other cancers, NMSCs generate a range of specimen types and are reported in a wide range of pathology practices. Limiting use of SPRP to NMSC at higher risk of progression and providing formatted templates for easy incorporation into laboratory information systems were essential to successful deployment. In the future, further consideration should be given to implementing the SPRP to include all relevant specimens, including non-head and neck and low-risk NMSC specimens.

Effect of the COVID-19 Pandemic on Rates and Epidemiology of Clostridioides difficile Infection in One VA Hospital.

The COVID-19 pandemic was associated with increases in some healthcare-associated infections. We investigated the impact of the pandemic on the rates and molecular epidemiology of Clostridioides difficile infection (CDI) within one VA hospital. We anticipated that the potential widespread use of antibiotics for pneumonia during the pandemic might increase CDI rates given that antibiotics are a major risk for CDI. Hospital data on patients with CDI and recurrent CDI (rCDI) were reviewed both prior to the COVID-19 pandemic (2015 to 2019) and during the pandemic (2020-2021). Restriction endonuclease analysis (REA) strain typing was performed on CD isolates recovered from stool samples collected from October 2019 to March 2022. CDI case numbers declined by 43.2% in 2020 to 2021 compared to the annual mean over the previous 5 years. The stool test positivity rate was also lower during the COVID-19 pandemic (14.3% vs. 17.2%; p = 0.013). Inpatient hospitalization rates declined, and rates of CDI among inpatients were reduced by 34.2% from 2020 to 2021. The mean monthly cases of rCDI also declined significantly after 2020 [3.38 (95% CI: 2.89-3.87) vs. 1.92 (95% CI: 1.27-2.56); p = <0.01]. Prior to the pandemic, REA group Y was the most prevalent CD strain among the major REA groups (27.3%). During the first wave of the pandemic, from 8 March 2020, to 30 June 2020, there was an increase in the relative incidence of REA group BI (26.7% vs. 9.1%); After adjusting for CDI risk factors, a multivariable logistic regression model revealed that the odds of developing an REA group BI CDI increased during the first pandemic wave (OR 6.41, 95% CI: 1.03-39.91) compared to the pre-pandemic period. In conclusion, the incidence of CDI and rCDI decreased significantly during the COVID-19 pandemic. In contrast, REA BI (Ribotype 027), a virulent, previously epidemic CD strain frequently associated with hospital transmission and outbreaks, reappeared as a prevalent strain during the first wave of the pandemic, but subsequently disappeared, and overall CDI rates declined.

Antimicrobial susceptibility of Clostridioides difficile to omadacycline and comparator antimicrobials.

BACKGROUND: Omadacycline is a novel aminomethylcycline tetracycline antimicrobial that was approved for the treatment of community-associated bacterial pneumonia (CABP) and acute bacterial skin and skin structure infections (ABSSSI) in 2018. Omadacycline has demonstrated a high degree of in vitro activity towards Clostridioides difficile and previous data have hypothesized that use of omadacycline for CABP or ABSSSI may decrease the risk of C. difficile infections. OBJECTIVES: To compare the in vitro antimicrobial activity of omadacycline versus commonly used antimicrobials for the approved indications of use. METHODS: We compared the antimicrobial activity of eight antimicrobials approved for CABP and ABSSSI against omadacycline by agar dilution on 200 clinically relevant contemporary C. difficile isolates representing local and national prevalent strain types. RESULTS: The in vitro omadacycline geometric mean MIC was 0.07 mg/L. Ceftriaxone resistance was noted in >50% of all isolates tested. The epidemic strain group, identified as restriction endonuclease analysis (REA) group BI, was commonly resistant to azithromycin (92%), moxifloxacin (86%) and clindamycin (78%). REA group DH strains had an elevated trimethoprim/sulfamethoxazole geometric mean MIC of 17.30 mg/L compared with the geometric mean MIC of 8.14 mg/L noted in all other isolates. In the REA group BK isolates that had a doxycycline MIC of ≥2 mg/L, the omadacycline MIC was <0.5 mg/L. CONCLUSIONS: Among 200 contemporary C. difficile isolates, there were no notable elevations in the in vitro omadacycline MIC, indicating a high level of activity towards C. difficile in comparison with commonly used antimicrobials for CABP and ABSSSI.

Three-dimensional food printing: its readiness for a food and nutrition insecure world.

Three-dimensional (3D) food printing is a rapidly emerging technology offering unprecedented potential for customised food design and personalised nutrition. Here, we evaluate the technological advances in extrusion-based 3D food printing and its possibilities to promote healthy and sustainable eating. We consider the challenges in implementing the technology in real-world applications. We propose viable applications for 3D food printing in health care, health promotion and food waste upcycling. Finally, we outline future work on 3D food printing in food safety, acceptability and economics, ethics and regulations.

Lactobacillus Bacteremia and Probiotics: A Review.

Lactobacilli are widely found in nature, are commensal microbes in humans, and are commonly used as probiotics. Concerns about probiotic safety have arisen due to reports of bacteremia and other Lactobacillus-associated infections. We reviewed the literature for articles on the pathogenicity of Lactobacillus spp. bacteremia and reports of probiotics in these patients. Our aim is to review these articles and update the present knowledge on the epidemiology of Lactobacillus spp. bacteremia and determine the role of probiotics in Lactobacillus bacteremia. Lactobacillus bacteremia is infrequent but has a higher risk of mortality and risk factors, including severe underlying diseases, immune system suppression, admission to intensive care units, and use of central venous catheters. A variety of Lactobacillus species may cause bacteremia and may or may not be associated with probiotic exposure. To determine if oral probiotics are the source of these infections, the blood isolates and the oral probiotic strain(s) must be compared by sensitive identification methods. The prevalence of Lactobacillus bacteremia is infrequent but is more common in patients taking probiotics compared to those not taking probiotics. Three probiotics (Lacticaseibacillus rhamnosus GG, Lactiplantibacillus plantarum, and Lacticaseibacillus paracasei) were directly linked with blood isolates from bacteremia patients using molecular identification assays.

Redefining Clostridioides difficile infection antibiotic response and clinical outcomes.

With the approval and development of narrow-spectrum antibiotics for the treatment of Clostridioides difficile infection (CDI), the primary endpoint for treatment success of CDI antibiotic treatment trials has shifted from treatment response at end of therapy to sustained response 30 days after completed therapy. The current definition of a successful response to treatment (three or fewer unformed bowel movements [UBMs] per day for 1-2 days) has not been validated, does not reflect CDI management, and could impair assessments for successful treatment at 30 days. We propose new definitions to optimise trial design to assess sustained response. Primarily, we suggest that the initial response at the end of treatment be defined as (1) three or fewer UBMs per day, (2) a reduction in UBMs of more than 50% per day, (3) a decrease in stool volume of more than 75% for those with ostomy, or (4) attainment of bowel movements of Bristol Stool Form Scale types 1-4, on average, by day 2 after completion of primary CDI therapy (ie, assessed on day 11 and day 12 of a 10-day treatment course) and following an investigator determination that CDI treatment can be ceased.

Effective Colonization by Nontoxigenic Clostridioides difficile REA Strain M3 (NTCD-M3) Spores following Treatment with Either Fidaxomicin or Vancomycin.

Colonization with nontoxigenic Clostridioides difficile strain M3 (NTCD-M3) has been demonstrated in susceptible hamsters and humans when administered after vancomycin treatment. NTCD-M3 has also been shown to decrease risk of recurrent C. difficile infection (CDI) in patients following vancomycin treatment for CDI. As there are no data for NTCD-M3 colonization after fidaxomicin treatment, we studied the efficacy of NTCD-M3 colonization and determined fecal antibiotic levels in a well-studied hamster model of CDI. Ten of 10 hamsters became colonized with NTCD-M3 after 5 days of treatment with fidaxomicin when NTCD-M3 was administered daily for 7 days after treatment discontinuation. The findings were nearly identical to 10 vancomycin-treated hamsters also given NTCD-M3. High fecal levels of OP-1118, the major fidaxomicin metabolite, and vancomycin were noted during treatment with the respective agents and modest levels noted 3 days after treatment discontinuation at the time when most of the hamsters became colonized. These findings support the ongoing development of NTCD-M3 for the prevention of recurrent CDI. IMPORTANCE NTCD-M3 is a novel live biotherapeutic, that has been shown in a Phase 2 clinical trial to prevent recurrence of C. difficile infection (CDI) when administered shortly after antibiotic treatment of the initial CDI episode. Fidaxomicin was not, however, in widespread use at the time this study was conducted. A large multi-center Phase 3 clinical trial is now currently in the planning stage, and it is anticipated that many patients eligible for this study will be treated with fidaxomicin. Since efficacy in the hamster model of CDI has predicted success in patients with CDI, we studied the ability of NTCD-M3 to colonize hamsters after treatment with either fidaxomicin or vancomycin.

Microbiota-Based Live Biotherapeutic RBX2660 for the Reduction of Recurrent Clostridioides difficile Infection in Older Adults With Underlying Comorbidities.

Background: Advanced age and underlying comorbidities are associated with greater rates of recurrence in patients with Clostridioides difficile infection (CDI). Reducing the likelihood of recurrence through treatment with an antimicrobial followed by a microbiota replacement therapy can decrease the burden of this infection and improve patient outcomes. We report the efficacy and safety of RBX2660, a microbiota-based live biotherapeutic, in older adults with recurrent CDI, grouped by comorbidities. Methods: In this post hoc subgroup analysis of the PUNCH CD3 trial, we assessed outcomes in older adults (age ≥65 years) grouped by Charlson Comorbidity Index severity scores at screening (moderate [3-4] and severe [≥5]) and by the presence of underlying cardiac, renal, or gastrointestinal disorders. Results: RBX2660 treatment success rates in older adults with comorbidities were consistent across subgroups and similar to those in the total RBX2660-treated population. A greater percentage of RBX2660-treated older adults remained free of CDI recurrence through 8 weeks following treatment compared with placebo-treated participants in all but 2 subgroups assessed. Across all subgroups, most treatment-emergent adverse events (TEAEs) were mild or moderate in severity and related to a preexisting condition. None of the serious or life-threatening TEAEs that occurred were related to RBX2660 or its administration. Occurrence of TEAEs did not cluster in any subgroup. Conclusions: RBX2660 is efficacious and safe in older adults with recurrent CDI and underlying comorbidities.