Hand and environmental hygiene: respective roles for MRSA, multi-resistant gram negatives, Clostridioides difficile, and Candida spp.

Healthcare-associated infections (HAIs) caused by multidrug-resistant organisms (MDROs) represent a global threat to human health and well-being. Because transmission of MDROs to patients often occurs via transiently contaminated hands of healthcare personnel (HCP), hand hygiene is considered the most important measure for preventing HAIs. Environmental surfaces contaminated with MDROs from colonized or infected patients represent an important source of HCP hand contamination and contribute to transmission of pathogens. Accordingly, facilities are encouraged to adopt and implement recommendations included in the World Health Organization hand hygiene guidelines and those from the Society for Healthcare Epidemiology of America/Infectious Diseases Society of America/Association for Professionals in Infection Control and Epidemiology. Alcohol-based hand rubs are efficacious against MDROs with the exception of Clostridiodes difficile, for which soap and water handwashing is indicated. Monitoring hand hygiene adherence and providing HCP with feedback are of paramount importance. Environmental hygiene measures to curtail MDROs include disinfecting high-touch surfaces in rooms of patients with C. difficile infection daily with a sporicidal agent such as sodium hypochlorite. Some experts recommend also using a sporicidal agent in rooms of patients colonized with C. difficile, and for patients with multidrug-resistant Gram-negative bacteria. Sodium hypochlorite, hydrogen peroxide, or peracetic acid solutions are often used for daily and/or terminal disinfection of rooms housing patients with Candida auris or other MDROs. Products containing only a quaternary ammonium agent are not as effective as other agents against C. auris. Portable medical equipment should be cleaned and disinfected between use on different patients. Detergents are not recommended for cleaning high-touch surfaces in MDRO patient rooms, unless their use is followed by using a disinfectant. Facilities should consider using a disinfectant instead of detergents for terminal cleaning of floors in MDRO patient rooms. Education and training of environmental services employees is essential in assuring effective disinfection practices. Monitoring disinfection practices and providing personnel with performance feedback using fluorescent markers, adenosine triphosphate assays, or less commonly cultures of surfaces, can help reduce MDRO transmission. No-touch disinfection methods such as electrostatic spraying, hydrogen peroxide vapor, or ultraviolet light devices should be considered for terminal disinfection of MDRO patient rooms. Bundles with additional measures are usually necessary to reduce MDRO transmission.

Structure-Activity Relationship of Inositol Thiophosphate Analogs as Allosteric Activators of Clostridioides difficile Toxin B.

Clostridioides difficile is a bacterium that causes life-threatening intestinal infections. Infection symptoms are mediated by a toxin secreted by the bacterium. Toxin pathogenesis is modulated by the intracellular molecule, inositol-hexakisphosphate (IP6). IP6 binds to a cysteine protease domain (CPD) on the toxin, inducing autoproteolysis, which liberates a virulence factor in the cell cytosol. We developed second-generation IP6 analogs designed to induce autoproteolysis in the gut lumen, prior to toxin uptake, circumventing pathogenesis. We synthesized a panel of thiophosphate-/sulfate-containing IP6 analogs and characterized their toxin binding affinity, autoproteolysis induction, and cation interactions. Our top candidate was soluble in extracellular cation concentrations, unlike IP6. The IP6 analogs were more negatively charged than IP6, which improved affinity and stabilization of the CPD, enhancing toxin autoproteolysis. Our data illustrate the optimization of IP6 with thiophosphate biomimetic which are more capable of inducing toxin autoproteolysis than the native ligand, warranting further studies in vivo.

Positive Intervention of Distinct Peptides in Clostridioides difficile Infection in a Mouse Model.

Clostridioides difficile infection (CDI) is a common healthcare-associated infection and the leading cause of gastroenteritis-related deaths worldwide. To investigate the effects of peptide composition of different protein products on CDI, we analyzed and compared the peptide sequences and compositions from Engraulis japonicus and Glycine max using Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS). An animal model of CDI was also established to investigate the potential therapeutic effects of these peptides in vivo. The peptide compositions of E. japonicus and G. max differed, with only 11% of the peptide sequences being identical. Oral administration of the tested peptides could reduce intestinal inflammation, repair the intestinal barrier, increase the proportion of beneficial bacteria, and reduce the proportion of harmful bacteria, providing a therapeutic effect against CDI. However, the peptides may differ considerably in some aspects. E. japonicus peptides were superior to G. max peptides in promoting colon epithelial cell proliferation and repairing tight intestinal cell junctions. Interestingly, the two sources of peptides have different effects on the cecal microbiome. E. japonicus peptides can effectively restore the diversity and richness of intestinal microbiota, while G. max peptides have poor regulatory effects on the intestinal microbiota structure. Overall, E. japonicus peptides showed better results than G. max peptides in treating CDI. This study supports the potential treatment of CDI with natural peptides and promotes the development of specialty foods for CDI enteritis. Clostridioides difficile infection (CDI) is a common healthcare-associated infection and the leading cause of gastroenteritis-related deaths worldwide. To investigate the effects of peptide composition of different protein products on CDI, we analyzed and compared the peptide sequences and compositions from Engraulis japonicus and Glycine max using Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS). An animal model of CDI was also established to investigate the potential therapeutic effects of these peptides in vivo. The peptide compositions of E. japonicus and G. max differed, with only 11% of the peptide sequences being identical. Oral administration of the tested peptides could reduce intestinal inflammation, repair the intestinal barrier, increase the proportion of beneficial bacteria, and reduce the proportion of harmful bacteria, providing a therapeutic effect against CDI. However, the peptides may differ considerably in some aspects. E. japonicus peptides were superior to G. max peptides in promoting colon epithelial cell proliferation and repairing tight intestinal cell junctions. Interestingly, the two sources of peptides have different effects on the cecal microbiome. E. japonicus peptides can effectively restore the diversity and richness of intestinal microbiota, while G. max peptides have poor regulatory effects on the intestinal microbiota structure.

Chemical optimization and derivatization of micrococcin p2 to target multiple bacterial infections: new antibiotics from thiopeptides.

Antimicrobial resistance poses a significant threat to humanity, and the development of new antibiotics is urgently needed. Our research has focused on thiopeptide antibiotics such as micrococcin P2 (MP2) and derivatives thereof as new anti-infective agents. Thiopeptides are sulfur-rich, structurally complex substances that exhibit potent activity against Gram-positive pathogens and Mycobacteria species, including clinically resistant strains. The clinical development of thiopeptides has been hampered by the lack of efficient synthetic platforms to conduct detailed structure-activity relationship studies of these natural products. The present contribution touches upon efficient synthetic routes to MP2 that laid the groundwork for clinical translation. The medicinal chemistry campaign on MP2 has been guided by computational molecular dynamic simulations and parallel investigations to improve drug-like properties, such as enhancing the aqueous solubility and optimizing antibacterial activity. Such endeavors have enabled identification of promising lead compounds, AJ-037 and AJ-206, against Mycobacterium avium complex (MAC). Extensive in vitro studies revealed that these compounds exert potent activity against MAC species, a subspecies of non-tuberculous mycobacteria (NTM) that proliferate inside macrophages. Two additional pre-clinical candidates have been identified: AJ-024, for the treatment of Clostridioides difficile infections, and AJ-147, for methicillin-resistant Staphylococcus aureus impetigo. Both compounds compare quite favorably with current first-line treatments. In particular, the ability of AJ-147 to downregulate pro-inflammatory cytokines adds a valuable dimension to its clinical use. In light of above, these new thiopeptide derivatives are well-poised for further clinical development.

Antimicrobial Face Masks and Mask Covers with a Salt-Coated Stacked Spunbond Polypropylene Fabric: Effective Inactivation of Resilient Pathogens and Prevention of Contact Transmission.

In response to the ongoing threat posed by respiratory diseases, ensuring effective transmission protection is crucial for public health. To address the drawbacks of single-use face masks/respirators, which can be a potential source of contact-based transmission, we have designed an antimicrobial face mask and mask covering utilizing a stack of salt-coated spunbond (SB) fabric. This fabric acts as an outer layer for the face mask and as a covering over a conventional mask, respectively. We evaluated the universal antimicrobial performance of the salt-coated three-stacked SB fabric against enveloped/nonenveloped viruses and spore-forming/nonspore-forming bacteria. The distinctive pathogen inactivation efficiency was confirmed, including resistant pathogens such as human rhinovirus and Clostridium difficile. In addition, we tested other filter attributes, such as filtration efficiency and breathability, to determine the optimal layer for salt coating and its effects on performance. Our findings revealed that the outer layer of a conventional face mask plays a crucial role in contact transmission through contaminated face masks and respirators. Through contact transmission experiments using droplets involving three types of contaminants (fluorescent dyes, bacteria, and viruses), the salt-coated stacked SB fabric demonstrated a superior effect in preventing contact transmission compared to SB or meltblown polypropylene fabrics─an issue challenging to existing masks. Our results demonstrate that the use of salt-coated stacked SB fabrics as (i) the outer layer of a mask and (ii) a mask cover over a mask enhances overall filter performance against infectious droplets, achieving high pathogen inactivation and low contact-based transmission while maintaining breathability.

Multifunctional host-defense peptides isolated from skin secretions of the banana tree dwelling frog Boana platanera (Hylidae; Hylinae).

Five host-defense peptides (figainin 2PL, hylin PL, raniseptin PL, plasticin PL, and peptide YL) were isolated from norepinephrine-stimulated skin secretions of the banana tree dwelling frog Boana platanera (Hylidae; Hylinae) collected in Trinidad. Raniseptin PL (GVFDTVKKIGKAVGKFALGVAKNYLNS.NH2) and figainin 2PL (FLGTVLKLGKAIAKTVVPMLTNAMQPKQ. NH2) showed potent and rapid bactericidal activity against a range of clinically relevant Gram-positive and Gram-negative ESKAPE + pathogens and Clostridioides difficile. The peptides also showed potent cytotoxic activity (LC50 values < 30 µM) against A549, MDA-MB-231 and HT29 human tumor-derived cell lines but appreciably lower hemolytic activity against mouse erythrocytes (LC50 = 262 ± 14 µM for raniseptin PL and 157 ± 16 µM for figainin 2PL). Hylin PL (FLGLIPALAGAIGNLIK.NH2) showed relatively weak activity against microorganisms but was more hemolytic. The glycine-leucine-rich peptide with structural similarity to the plasticins (GLLSTVGGLVGGLLNNLGL.NH2) and the non-cytotoxic peptide YL (YVPGVIESLL.NH2) lacked antimicrobial and cytotoxic activities. Hylin PL, raniseptinPL and peptide YL stimulated the rate of release of insulin from BRIN-BD11 clonal ß-cells at concentrations ≥100 nM. Peptide YL was the most effective (2.3-fold increase compared with basal rate at 1 µM concentration) and may represent a template for the design of a new class of incretin-based anti-diabetic drugs.

Comparative Study of Adenosine Analogs as Inhibitors of Protein Arginine Methyltransferases and a Clostridioides difficile-Specific DNA Adenine Methyltransferase.

S-Adenosyl-l-methionine (SAM) analogs are adaptable tools for studying and therapeutically inhibiting SAM-dependent methyltransferases (MTases). Some MTases play significant roles in host-pathogen interactions, one of which is Clostridioides difficile-specific DNA adenine MTase (CamA). CamA is needed for efficient sporulation and alters persistence in the colon. To discover potent and selective CamA inhibitors, we explored modifications of the solvent-exposed edge of the SAM adenosine moiety. Starting from the two parental compounds (6e and 7), we designed an adenosine analog (11a) carrying a 3-phenylpropyl moiety at the adenine N6-amino group, and a 3-(cyclohexylmethyl guanidine)-ethyl moiety at the sulfur atom off the ribose ring. Compound 11a (IC50 = 0.15 µM) is 10× and 5× more potent against CamA than 6e and 7, respectively. The structure of the CamA-DNA-inhibitor complex revealed that 11a adopts a U-shaped conformation, with the two branches folded toward each other, and the aliphatic and aromatic rings at the two ends interacting with one another. 11a occupies the entire hydrophobic surface (apparently unique to CamA) next to the adenosine binding site. Our work presents a hybrid knowledge-based and fragment-based approach to generating CamA inhibitors that would be chemical agents to examine the mechanism(s) of action and therapeutic potentials of CamA in C. difficile infection.

Fecal Microbiota Transplantation Increases Colonic IL-25 and Dampens Tissue Inflammation in Patients with Recurrent Clostridioides difficile.

Clostridioides difficile infection (CDI) is the most common hospital-acquired infection in the United States. Antibiotic-induced dysbiosis is the primary cause of susceptibility, and fecal microbiota transplantation (FMT) has emerged as an effective therapy for recurrence. We previously demonstrated in the mouse model of CDI that antibiotic-induced dysbiosis reduced colonic expression of interleukin 25 (IL-25) and that FMT protected in part by restoring IL-25 signaling. Here, we conducted a prospective study in humans to test if FMT induced IL-25 expression in the colons of patients with recurrent CDI (rCDI). Colonic biopsy specimens and blood were collected at the time of FMT and 60 days later. Colon biopsy specimens were analyzed for IL-25 protein levels, total tissue transcriptome, and epithelium-associated microbiota before and after FMT, and peripheral immune cells were immunophenotyped. FMT increased alpha diversity of the colonic microbiota and levels of IL-25 in colonic tissue. In addition, FMT increased expression of homeostatic genes and repressed inflammatory genes. Finally, circulating Th17 cells were decreased post-FMT. The increase in levels of the cytokine IL-25 accompanied by decreased inflammation is consistent with FMT acting in part to protect from recurrent CDI via restoration of commensal activation of type 2 immunity. IMPORTANCE Fecal microbiota transplantation (FMT) is an effective treatment for C. difficile infection for most patients; however, introducing a complex mixture of microbes also has had unintended consequences for some patients. Attempts to create a standardized probiotic therapeutic that recapitulates the efficacy of FMT have been unsuccessful to date. We sought to understand what immune markers are changed in patients undergoing FMT to treat recurrent C. difficile infection and identified an immune signaling molecule, IL-25, that was restored by FMT. This finding indicates that adjunctive therapy with IL-25 could be useful in treating C. difficile infection.

Ebselen Not Only Inhibits Clostridioides difficile Toxins but Displays Redox-Associated Cellular Killing.

Ebselen, a reactive organoselenium compound, was shown to inhibit toxins TcdA and TcdB by covalently binding to their cysteine protease domains. It was suggested that ebselen lacked antimicrobial activity against Clostridioides difficile. However, this perception conflicts with C. difficile having essential cysteine-containing enzymes that could be potential targets and the reported antimicrobial activity of ebselen against other species. Hence, we reevaluated the anti-C. difficile properties of ebselen. Susceptibility testing revealed that its activity was either slightly reduced by pyruvate found in Wilkins-Chalgren agar or obliterated by blood in brucella agar. In brain heart infusion (BHI) agar, ebselen inhibited most C. difficile strains (MICs of 2 to 8 µg/ml), except for ribotype 078 that was intrinsically resistant (MIC = 32 to 128 µg/ml). Against C. difficile R20291, at concentrations below its minimal bactericidal concentration (MBC), 16 µg/ml, ebselen inhibited production of toxins and spores. Transcriptome analysis revealed that ebselen altered redox-associated processes and cysteine metabolism and enhanced expression of Stickland proline metabolism, likely to regenerate NAD+ from NADH. In cellular assays, ebselen induced uptake of cysteine, depleted nonprotein thiols, and disrupted the NAD+/NADH ratio. Taken together, killing of C. difficile cells by ebselen occurs by a multitarget action that includes disrupting intracellular redox, which is consistent with ebselen being a reactive molecule. However, the physiological relevance of these antimicrobial actions in treating acute C. difficile infection (CDI) is likely to be undermined by host factors, such as blood, which protect C. difficile from killing by ebselen. IMPORTANCE We show that ebselen kills pathogenic C. difficile by disrupting its redox homeostasis, changing the normal concentrations of NAD+ and NADH, which are critical for various metabolic functions in cells. However, this antimicrobial action is hampered by host components, namely, blood. Future discovery of ebselen analogues, or mechanistically similar compounds, that remain active in blood could be drug leads for CDI or probes to study C. difficile redox biology in vivo.

An Osmotic Laxative Renders Mice Susceptible to Prolonged Clostridioides difficile Colonization and Hinders Clearance.

Antibiotics are a major risk factor for Clostridioides difficile infections (CDIs) because of their impact on the microbiota. However, nonantibiotic medications such as the ubiquitous osmotic laxative polyethylene glycol 3350 (PEG 3350) also alter the microbiota. Clinicians also hypothesize that PEG helps clear C. difficile. But whether PEG impacts CDI susceptibility and clearance is unclear. To examine how PEG impacts susceptibility, we treated C57BL/6 mice with 5-day and 1-day doses of 15% PEG in the drinking water and then challenged the mice with C. difficile 630. We used clindamycin-treated mice as a control because they consistently clear C. difficile within 10 days postchallenge. PEG treatment alone was sufficient to render mice susceptible, and 5-day PEG-treated mice remained colonized for up to 30 days postchallenge. In contrast, 1-day PEG-treated mice were transiently colonized, clearing C. difficile within 7 days postchallenge. To examine how PEG treatment impacts clearance, we administered a 1-day PEG treatment to clindamycin-treated, C. difficile-challenged mice. Administering PEG to mice after C. difficile challenge prolonged colonization up to 30 days postchallenge. When we trained a random forest model with community data from 5 days postchallenge, we were able to predict which mice would exhibit prolonged colonization (area under the receiver operating characteristic curve [AUROC] = 0.90). Examining the dynamics of these bacterial populations during the postchallenge period revealed patterns in the relative abundances of Bacteroides, Enterobacteriaceae, Porphyromonadaceae, Lachnospiraceae, and Akkermansia that were associated with prolonged C. difficile colonization in PEG-treated mice. Thus, the osmotic laxative PEG rendered mice susceptible to C. difficile colonization and hindered clearance. IMPORTANCE Diarrheal samples from patients taking laxatives are typically rejected for Clostridioides difficile testing. However, there are similarities between the bacterial communities from people with diarrhea and those with C. difficile infections (CDIs), including lower diversity than the communities from healthy patients. This observation led us to hypothesize that diarrhea may be an indicator of C. difficile susceptibility. We explored how osmotic laxatives disrupt the microbiota's colonization resistance to C. difficile by administering a laxative to mice either before or after C. difficile challenge. Our findings suggest that osmotic laxatives disrupt colonization resistance to C. difficile and prevent clearance among mice already colonized with C. difficile. Considering that most hospitals recommend not performing C. difficile testing on patients taking laxatives, and laxatives are prescribed prior to administering fecal microbiota transplants via colonoscopy to patients with recurrent CDIs, further studies are needed to evaluate if laxatives impact microbiota colonization resistance in humans.

Effective inhibition of Clostridioides difficile by the novel peptide CM-A.

Clostridioides difficile infection is the most common cause of nosocomial and antibiotic-associated diarrhea. C. difficile treatment is increasingly likely to fail, and the recurrence rate is high. Antimicrobial peptides are considered an alternative treatment for many infectious diseases, including those caused by antibiotic resistant bacteria. In the present study, we identified a CM peptide, a hybrid of cecropin A and melittin, and its derivative which possesses potent antimicrobial activity against C. difficile strain 630. CM peptide exhibited antibacterial activity with minimum inhibitory concentration of 3.906 µg/ml (2.21 µM). A modified derivative of CM, CM-A, exhibited even greater activity with a minimum inhibitory concentration of 1.953 µg/ml (1.06 µM) and a minimum bactericidal concentration of 7.8125 µg/ml (4.24 µM), which indicates that CM-A peptide is more efficient than its parent peptide. A fluorescence-activated cell sorter analysis revealed that the membrane of C. difficile 630 could be an important target for CM-A. This peptide induced high levels of cell depolarization and cell permeability on C. difficile cell membrane. Moreover, electron microscopy imaging showed that CM-A interferes with the C. difficile cell membrane. Hence, the antimicrobial peptide CM-A may represent a promising novel approach for the treatment of C. difficile infections.

Epidemiologic and Clinical Characteristics of Clostridioides difficile Infections in Hospitalized and Outpatient Pediatric Oncology and Hematopoietic Stem Cell Transplant Patients.

BACKGROUND: The epidemiology and clinical course of Clostridioides difficile infection (CDI) in children, especially with cancer, are poorly defined. We aim to describe the epidemiology, clinical features and outcomes of CDI and to identify risk factors for recurrence in a pediatric oncology center. METHODS: This is a retrospective cohort study of CDI in pediatric oncology and hematopoietic stem cell transplant (HSCT) patients in 2016 and 2017. CDI cases were identified by positive C. difficile test in symptomatic patients. CDI episodes were classified as incident, duplicate or recurrent and community-onset, hospital-onset or community-onset healthcare facility-associated. Data about clinical course and outcomes were abstracted. Risk factors for CDI recurrence were assessed by logistic regression. RESULTS: One hundred seventy-eight patients 1 year of age and older developed 291 CDI episodes; 78% were incident and 22% recurrent. Underlying diagnoses were leukemia/lymphoma (57%) and solid/brain tumors (41%); 30% were HSCT recipients. Antibiotics, chemotherapy, antacids, steroids and laxatives were received by 96%, 82%, 70%, 47% and 15%, respectively. Half of the patients were neutropenic. Twenty-two percent of outpatients with CDI required hospitalization. Chemotherapy was delayed in 25%. There were no intensive care unit admissions nor deaths due to CDI. Exposure to H2-antagonists was identified as an independent risk factor for CDI recurrence. CONCLUSIONS: Although CDI in pediatric oncology and HSCT patients was associated with chemotherapy delay and hospitalization in approximately a quarter of patients, it was not associated with morbidity or mortality because patients had no attributable intensive care unit admission nor death. H2-antagonists are independent risk factors for CDI recurrence.

The Importance of Therapeutically Targeting the Binary Toxin from Clostridioides difficile.

Novel therapeutics are needed to treat pathologies associated with the Clostridioides difficile binary toxin (CDT), particularly when C. difficile infection (CDI) occurs in the elderly or in hospitalized patients having illnesses, in addition to CDI, such as cancer. While therapies are available to block toxicities associated with the large clostridial toxins (TcdA and TcdB) in this nosocomial disease, nothing is available yet to treat toxicities arising from strains of CDI having the binary toxin. Like other binary toxins, the active CDTa catalytic subunit of CDT is delivered into host cells together with an oligomeric assembly of CDTb subunits via host cell receptor-mediated endocytosis. Once CDT arrives in the host cell's cytoplasm, CDTa catalyzes the ADP-ribosylation of G-actin leading to degradation of the cytoskeleton and rapid cell death. Although a detailed molecular mechanism for CDT entry and host cell toxicity is not yet fully established, structural and functional resemblances to other binary toxins are described. Additionally, unique conformational assemblies of individual CDT components are highlighted herein to refine our mechanistic understanding of this deadly toxin as is needed to develop effective new therapeutic strategies for treating some of the most hypervirulent and lethal strains of CDT-containing strains of CDI.

Entry of spores into intestinal epithelial cells contributes to recurrence of Clostridioides difficile infection.

Clostridioides difficile spores produced during infection are important for the recurrence of the disease. Here, we show that C. difficile spores gain entry into the intestinal mucosa via pathways dependent on host fibronectin-α5ß1 and vitronectin-αvß1. The exosporium protein BclA3, on the spore surface, is required for both entry pathways. Deletion of the bclA3 gene in C. difficile, or pharmacological inhibition of endocytosis using nystatin, leads to reduced entry into the intestinal mucosa and reduced recurrence of the disease in a mouse model. Our findings indicate that C. difficile spore entry into the intestinal barrier can contribute to spore persistence and infection recurrence, and suggest potential avenues for new therapies.

Effect of oral vancomycin dose on outcomes in patients with Clostridioides difficile infection.

Clostridioides difficile infection (CDI) is a significant cause of morbidity and mortality. Oral vancomycin is a cornerstone of CDI treatment, but dosing strategies in clinical practice may differ from guideline recommendations. This study aimed to determine differences in outcomes between patients treated with standard (125 mg QID) and high-dose (≥250 mg QID) oral vancomycin. This dual-centre study evaluated adult patients admitted between January 2013 and July 2017. Patients were included in the study if they had a positive C. difficile toxin PCR, symptomatic infection and received ≥48 h of oral vancomycin. Disease severity was characterised using a variety of classifiers, including guideline definitions. The primary outcome was 90-day CDI recurrence; secondary outcomes included clinical failure, in-hospital mortality and 90-day re-admission. Inverse probability of treatment weighting (IPTW) was conducted to balance differences between groups. A total of 535 patients were included; 261 received standard and 274 received high-dose vancomycin. Baseline demographics were similar between groups, except that patients receiving high-dose vancomycin were more likely to have more severe disease and to be admitted to the ICU. Few patients had fulminant disease (14.4%). No significant differences in recurrence (OR, 1.52, 95% CI 0.82-2.84), clinical failure (OR, 0.64, 95% CI 0.328-1.26), mortality (OR, 1.44, 95% CI 0.78-2.66) or re-admission (OR, 1.03, 95% CI 0.70-1.51) were identified between patients receiving standard and high-dose vancomycin in the IPTW analyses. No differences in recurrence, mortality or re-admission were identified between standard and high-dose vancomycin for the treatment of CDI not requiring surgery.

Diagnostic Modality of Clostridioides difficile Infection Predicts Treatment Response and Outcomes in Inflammatory Bowel Disease.

BACKGROUND: Inflammatory bowel disease (IBD) patients are at increased risk of developing Clostridioides difficile infection (CDI). Common methods to diagnose CDI involve a combination of tests including the toxin A/B enzyme immunoassay (Toxin) and toxin gene polymerase chain reaction assay (PCR). Disease outcomes in Toxin+ versus Toxin-PCR+ IBD patients remain unclear. AIMS: This study aimed to examine the response to antibiotics and risk of IBD therapy escalation in Toxin+ versus Toxin-PCR+ patients. METHODS: IBD patients at an academic center with CDI diagnosis based on Toxin+ or Toxin-PCR+ from 2012 to 2017 were identified. Comparisons of response to antibiotics within 30 days and escalation of IBD therapy within 90 days of CDI diagnosis between these two groups were analyzed by Chi-square analysis. Multivariable regression analysis examined factors associated with antibiotic response. RESULTS: Among 92 patients included, 61% had Crohn's disease and 39% had ulcerative colitis. 70% tested Toxin-PCR+. 60% received vancomycin or fidaxomicin to treat CDI. 82% of Toxin+ patients responded to antibiotics compared to 25% of Toxin-PCR+ patients (p < 0.001). 21% of Toxin+ patients required IBD therapy escalation compared to 63% of Toxin-PCR+ patients (p < 0.001). When adjusted for the types of antibiotics used, IBD subtypes, and immunosuppression status, positivity to Toxin (OR 14.85, CI 4.62-47.72) was the most significant predictor of response to antibiotics. CONCLUSIONS: Toxin+ compared to Toxin-PCR+ IBD patients had a significantly higher rate of response to antibiotics and lower chances of requiring IBD therapy escalation. Future outcome studies involving CDI in IBD patients should be stratified by modality of diagnosis.

Efficacy of novel aqueous photo-chlorine dioxide against a human norovirus surrogate, bacteriophage MS2 and Clostridium difficile endospores, in suspension, on stainless steel and under greenhouse conditions.

AIMS: The efficacy of a novel photochemical method for generating chlorine dioxide (photoClO2 ) was evaluated against human noroviruses (HuNoV) surrogate, bacteriophage MS2, and Clostridium difficile endospores. METHODS AND RESULTS: Chlorine dioxide was generated by mixing 1% sodium chlorite with 10 parts-per-million (ppm) Eosin Y and irradiating with a photo-activator-excitable light. PhotoClO2 efficacy was assessed against bacteriophage MS2 and C. difficile endospores in suspension, on hard surfaces and greenhouse conditions under soiled and unsoiled conditions. The estimated effective photoClO2 produced and consumed was 20·39 ± 0·16 ppm at a rate of 8·16 ppm per min in a 1% sodium chlorite solution. In suspension, MS2 phage was reduced by 3·35 and >5·10 log10 PFU per ml in 120 and 90 min, with and without soil, respectively. At the same time, when dried on stainless steel surface, MS2 phage was reduced by >4·53 log10 PFU per carrier in 30 min under both conditions. On the other hand, C. difficile endospores in suspension were reduced by 2·26 and 3·65 log10 CFU per ml in 120 min with and without soiling, respectively. However, on stainless steel surface, maximal reductions of the C. difficile endospores were 0·8 and 1·5 log10 CFU per carrier with and without soiling, respectively, and a maximal reduction of 2·97 log10 CFU per carrier under greenhouse conditions at 24 h. CONCLUSIONS: Overall, photoClO2 showed promise as a technology to control HuNoV contamination on environmental surfaces but requires further optimization and testing against C. difficile endospores. SIGNIFICANCE AND IMPACT OF THE STUDY: Results from this investigation will serve as a model for how to generate and quantify photoClO2 and how to appropriately evaluate this new class of disinfectants against environmentally resilient pathogens: viruses and bacterial endospores.

Repurposing the Veterinary Antiprotozoal Drug Ronidazole for the Treatment of Clostridioides difficile Infection.

Clostridioides difficile infection (CDI) is a principal cause of hospital-acquired infections and fatalities worldwide. The need for new, more potent anticlostridial agents is far from being met. Drug repurposing can be utilized as a rapid and cost-efficient method of drug development. The current study was conducted to evaluate the activity of ronidazole, a veterinary antiprotozoal drug, as a potential treatment for CDI. Ronidazole inhibited the growth of clinical C. difficile isolates (including NAP1 and toxigenic strains) at a very low concentration (0.125 µg/mL) and showed superior killing kinetics compared with metronidazole, an anticlostridial agent from the same chemical category. In addition, ronidazole did not inhibit growth of several commensal organisms naturally present in the human intestine that play a protective role in preventing CDIs. Furthermore, ronidazole was found to be non-toxic to human gut cells and permeated a monolayer of colonic epithelial cells (Caco-2) at a slower rate than metronidazole. Finally, ronidazole outperformed metronidazole when both were tested at a dose of 1 mg/kg daily in a mouse model of CDI. Overall, ronidazole merits further investigation as a potential treatment for CDIs.

Reuterin disrupts Clostridioides difficile metabolism and pathogenicity through reactive oxygen species generation.

Antibiotic resistance is one of the world's greatest public health challenges and adjunct probiotic therapies are strategies that could lessen this burden. Clostridioides difficile infection (CDI) is a prime example where adjunct probiotic therapies could decrease disease incidence through prevention. Human-derived Lactobacillus reuteri is a probiotic that produces the antimicrobial compound reuterin known to prevent C. difficile colonization of antibiotic-treated fecal microbial communities. However, the mechanism of inhibition is unclear. We show that reuterin inhibits C. difficile outgrowth from spores and vegetative cell growth, however, no effect on C. difficile germination or sporulation was observed. Consistent with published studies, we found that exposure to reuterin stimulated reactive oxygen species (ROS) in C. difficile, resulting in a concentration-dependent reduction in cell viability that was rescued by the antioxidant glutathione. Sublethal concentrations of reuterin enhanced the susceptibility of vegetative C. difficile to vancomycin and metronidazole treatment and reduced toxin synthesis by C. difficile. We also demonstrate that reuterin is protective against C. difficile toxin-mediated cellular damage in the human intestinal enteroid model. Overall, our results indicate that ROS are essential mediators of reuterin activity and show that reuterin production by L. reuteri is compatible as a therapeutic in a clinically relevant model.