Bile salt hydrolases shape the bile acid landscape and restrict Clostridioides difficile growth in the murine gut

Bile acids (BAs) mediate the crosstalk between human and microbial cells and influence diseases including Clostridioides difficile infection (CDI). While bile salt hydrolases (BSHs) shape the BA pool by deconjugating conjugated BAs, the basis for their substrate selectivity and impact on C. difficile remain elusive. Here we survey the diversity of BSHs in the gut commensals Lactobacillaceae, which are commonly used as probiotics, and other members of the human gut microbiome. We structurally pinpoint a loop that predicts BSH preferences for either glycine or taurine substrates. BSHs with varying specificities were shown to restrict C. difficile spore germination and growth in vitro and colonization in pre-clinical in vivo models of CDI. Furthermore, BSHs reshape the pool of microbial conjugated bile acids (MCBAs) in the murine gut, and these MCBAs can further restrict C. difficile virulence in vitro. The recognition of conjugated BAs by BSHs defines the resulting BA pool, including the expansive MCBAs. This work provides insights into the structural basis of BSH mechanisms that shape the BA landscape and promote colonization resistance against C. difficile.

The Environment, Farm Animals and Foods as Sources of Clostridioides difficile Infection in Humans

The recent discovery of the same Clostridioides difficile ribotypes associated with human infection in a broad range of environments, animals and foods, coupled with an ever-increasing rate of community-acquired infections, suggests this pathogen may be foodborne. The objective of this review was to examine the evidence supporting this hypothesis. A review of the literature found that forty-three different ribotypes, including six hypervirulent strains, have been detected in meat and vegetable food products, all of which carry the genes encoding pathogenesis. Of these, nine ribotypes (002, 003, 012, 014, 027, 029, 070, 078 and 126) have been isolated from patients with confirmed community-associated C. difficile infection (CDI). A meta-analysis of this data suggested there is a higher risk of exposure to all ribotypes when consuming shellfish or pork, with the latter being the main foodborne route for ribotypes 027 and 078, the hypervirulent strains that cause most human illnesses. Managing the risk of foodborne CDI is difficult as there are multiple routes of transmission from the farming and processing environment to humans. Moreover, the endospores are resistant to most physical and chemical treatments. The most effective current strategy is, therefore, to limit the use of broad-spectrum antibiotics while advising potentially vulnerable patients to avoid high-risk foods such as shellfish and pork.

Impact of the cefazolin shortage on the selection and cost of parenteral antibiotics during the supply disruption period in Japan: A controlled interrupted time series analysis

BACKGROUND

A serious shortage of cefazolin (CEZ) occurred in Japan in 2019. We compared the impact of the CEZ shortage on the selection of parenteral antibiotics at affected and non-affected hospitals.

METHODS

The data were extracted from a nationwide Japanese administrative database and included all hospitalized cases between April 2016 and December 2020. We defined 'hospitals with shortage' as those hospitals with a statistically significant decrease in the use of CEZ during the supply disruption period compared to the same months of the previous year; other hospitals as 'hospitals without shortage'. We determined the proportion of each selected parenteral antibiotic use to the sum of all selected antibiotic use in the two groups of hospitals during the supply disruption period and during the same months of the previous year. A controlled interrupted time series (CITS) analysis was conducted to estimate the impact of the CEZ shortage on each antibiotic use and the cost of all parenteral antibiotics per patient day in hospitals with shortage as compared to those without shortage.

RESULTS

In the hospitals with shortage, the proportion of CEZ use to the sum of all selected antibiotics decreased (23.5-11.1%). The decrease in CEZ use was mainly offset by the use of ceftriaxone, ceftriaxone, and ampicillin/sulbactam. The CITS analysis showed a statistically significant increase in the use of broader-spectrum beta-lactams and clindamycin during the supply disruption period (flomoxef up 58.1%, cefotiam up 63.1%, cefmetazole up 14.5%, ceftriaxone up 13.9%, and clindamycin up 20.1%). The analysis showed no statistically significant change in the cost of all parenteral antibiotics per patient day.

CONCLUSIONS

During the CEZ supply disruption, there was a statistically significant increase in the use of broader-spectrum beta-lactams and clindamycin in hospitals with shortage compared with those without shortage.

Evaluating the Impact of a Pharmacist-Led Antimicrobial Stewardship Intervention at Discharge in a Community, Nonteaching Hospital

INTRODUCTION

Approximately 30% to 50% of hospital discharge antimicrobials are inappropriate. Limited data exist on approaches to improve antimicrobial prescribing practices at the time of discharge from a community hospital. Objective: To assess the impact of a comprehensive pharmacist-led antimicrobial stewardship intervention at discharge.

METHODS

We conducted a quasi-experimental, pre-post study. A biphasic intervention took place on 2 medicine units from November 2019 to May 2020 at a community hospital. Baseline data were collected, followed by prescriber education on antimicrobial stewardship to both units (education phase). Next, a pharmacist-led intervention took place on one unit (intervention phase). The primary outcome was composite appropriateness of an oral antimicrobial prescribed to an adult at the time of discharge, defined by narrow spectrum of activity, dosing, and duration of therapy. The primary outcome was assessed using Fisher exact test.

RESULTS

Baseline composite appropriateness was 30% (n = 12) on the control unit and 30.8% (n = 20) on the intervention unit. From baseline to posteducation, no significant change in composite appropriateness was found on the control (30% to 26.7%, P = 0.256) or intervention (30.8% to 19.4%, P = 0.09) unit. There was no significant difference between the education to intervention phase (26.7% vs 35%, P = 0.254) on the control unit. On the intervention unit, a significant difference in composite appropriateness was found from the education to intervention phase (19.4% vs 47.8%, P = 0.017).

CONCLUSION AND RELEVANCE

A pharmacist-led intervention improved appropriateness of oral antimicrobials prescribed at discharge. One-time education was insufficient for improving antimicrobial stewardship.

Adverse effects of antibiotics in children with cancer: are short-course antibiotics for febrile neutropenia part of the solution?

INTRODUCTION

Febrile neutropenia is a common complication experienced by children with cancer or those undergoing hematopoietic stem cell transplantation. Repeated episodes of febrile neutropenia result in cumulative exposure to broad-spectrum antibiotics with potential for a range of serious adverse effects. Short-course antibiotics, even in patients with high-risk febrile neutropenia, may offer a solution.

AREAS COVERED

This review addresses the known broad effects of antibiotics, highlights developments in understanding the relationship between cancer, antibiotics, and the gut microbiome, and discusses emerging evidence regarding long-term adverse antibiotic effects. The authors consider available evidence to guide the duration of empiric antibiotics in pediatric febrile neutropenia and directions for future research.

EXPERT OPINION

Broad-spectrum antibiotics are associated with antimicrobial resistance, Clostridioides difficile infection, invasive candidiasis, significant disturbance of the gut microbiome and may seriously impact outcomes in children with cancer or undergoing allogenic hematopoietic stem cell transplant. Short-course empiric antibiotics are likely safe in most children with febrile neutropenia and present a valuable opportunity to reduce the risks of antibiotic exposure.

HexSDF Is Required for Synthesis of a Novel Glycolipid That Mediates Daptomycin and Bacitracin Resistance in C. difficile

Clostridioides difficile is a Gram-positive opportunistic pathogen responsible for 250,000 hospital-associated infections, 12,000 hospital-associated deaths, and $1 billion in medical costs in the United States each year. There has been recent interest in using a daptomycin analog, surotomycin, to treat C. difficile infections. Daptomycin interacts with phosphatidylglycerol and lipid II to disrupt the membrane and halt peptidoglycan synthesis. C. difficile has an unusual lipid membrane composition, as it has no phosphatidylserine or phosphatidylethanolamine, and ~50% of its membrane is composed of glycolipids, including the unique C. difficile lipid aminohexosyl-hexosyldiradylglycerol (HNHDRG). We identified a two-component system (TCS), HexRK, that is required for C. difficile resistance to daptomycin. Using transcriptome sequencing (RNA-seq), we found that HexRK regulates expression of hexSDF, a three-gene operon of unknown function. Based on bioinformatic predictions, hexS encodes a monogalactosyldiacylglycerol synthase, hexD encodes a polysaccharide deacetylase, and hexF encodes an MprF-like flippase. Deletion of hexRK leads to a 4-fold decrease in daptomycin MIC, and that deletion of hexSDF leads to an 8- to 16-fold decrease in daptomycin MIC. The ΔhexSDF mutant is also 4-fold less resistant to bacitracin but no other cell wall-active antibiotics. Our data indicate that in the absence of HexSDF, the phospholipid membrane composition is altered. In wild-type (WT) C. difficile, the unique glycolipid HNHDRG makes up ~17% of the lipids in the membrane. However, in a ΔhexSDF mutant, HNHDRG is completely absent. While it is unclear how HNHDRG contributes to daptomycin resistance, the requirement for bacitracin resistance suggests it has a general role in cell membrane biogenesis. IMPORTANCE Clostridioides difficile is a major cause of hospital-acquired diarrhea and represents an urgent concern due to the prevalence of antibiotic resistance and the rate of recurrent infections. Little is understood about C. difficile membrane lipids, but a unique glycolipid, HNHDRG, has been previously identified in C. difficile and, currently, has not been identified in other organisms. Here, we show that HexSDF and HexRK are required for synthesis of HNHDRG and that production of HNHDRG impacts resistance to daptomycin and bacitracin.

Appropriateness of Empirical Prescriptions of Ceftriaxone and Identification of Opportunities for Stewardship Interventions: A Single-Centre Cross-Sectional Study

Third-generation cephalosporins are widely used due to the convenient spectrum of activity, safety, and posology. However, they are associated with the emergence of multidrug-resistant organisms, which makes them important targets for antimicrobial stewardship interventions. We aimed to assess the appropriateness of empirical prescriptions of ceftriaxone in a tertiary hospital. This cross-sectional study analysed empirical ceftriaxone prescriptions in January and June 2021. Patients under other antimicrobials 48 h before admission were excluded. The quality of ceftriaxone prescription was assessed regarding the initial appropriateness, duration of inappropriate ceftriaxone therapy, and missed opportunities for de-escalation. Of 465 prescriptions, 46.5% were inappropriate. The ceftriaxone prescription was inappropriate in 95.7% of lower respiratory tract infections (LRTI) globally and in nearly 40% of urinary tract infections (UTI) in medical and intensive care departments. Intensive care, internal medicine, and palliative care departments showed the highest number of inappropriate ceftriaxone prescriptions and longer length of inappropriate ceftriaxone prescriptions compared to the hospital's average. Improvement of empirical ceftriaxone prescription in LRTI and urinary infections, adherence to local guidelines and de-escalation practices, and targeted interventions focusing on critical departments may significantly reduce the inappropriate empirical use of ceftriaxone.

From signal transduction to protein toxins-a narrative review about milestones on the research route of C. difficile toxins

Selected findings about Clostridioides difficile (formerly Clostridium difficile) toxins are presented in a narrative review. Starting with a personal view on research about G proteins, adenylyl cyclase, and ADP-ribosylating toxins in the laboratory of Günter Schultz in Heidelberg, milestones of C. difficile toxin research are presented with the focus on toxin B (TcdB), covering toxin structure, receptor binding, toxin up-take and refolding, the intracellular actions of TcdB, and the treatment of C. difficile infection.

Design of 8-mer Peptides that Block Clostridioides difficile Toxin A in Intestinal Cells

Clostridioides difficile ( C. diff .) is a bacterium that causes severe diarrhea and inflammation of the colon. The pathogenicity of C. diff . infection is derived from two major toxins, toxins A (TcdA) and B (TcdB). Peptide inhibitors that can be delivered to the gut to inactivate these toxins are an attractive therapeutic strategy. In this work, we present a new approach that combines a pep tide b inding d esign algorithm (PepBD), molecular-level simulations, rapid screening of candidate peptides for toxin binding, a primary human cell-based assay, and surface plasmon resonance (SPR) measurements to develop peptide inhibitors that block the glucosyltransferase activity of TcdA by targeting its glucosyltransferase domain (GTD). Using PepBD and explicit-solvent molecular dynamics simulations, we identified seven candidate peptides, SA1-SA7. These peptides were selected for specific TcdA GTD binding through a custom solid-phase peptide screening system, which eliminated the weaker inhibitors SA5-SA7. The efficacies of SA1-SA4 were then tested using a trans-epithelial electrical resistance (TEER) assay on monolayers of the human gut epithelial culture model. One peptide, SA1, was found to block TcdA toxicity in primary-derived human jejunum (small intestinal) and colon (large intestinal) epithelial cells. SA1 bound TcdA with a K D of 56.1 ± 29.8 nM as measured by surface plasmon resonance (SPR).

Significance Statement

Infections by Clostridioides difficile , a bacterium that targets the large intestine (colon), impact a significant number of people worldwide. Bacterial colonization is mediated by two exotoxins: toxins A and B. Short peptides that can inhibit the biocatalytic activity of these toxins represent a promising strategy to prevent and treat C. diff . infection. We describe an approach that combines a Peptide B inding D esign (PepBD) algorithm, molecular-level simulations, a rapid screening assay to evaluate peptide:toxin binding, a primary human cell-based assay, and surface plasmon resonance (SPR) measurements to develop peptide inhibitors that block Toxin A in small intestinal and colon epithelial cells. Importantly, our designed peptide, SA1, bound toxin A with nanomolar affinity and blocked toxicity in colon cells.

Antibiotic use for respiratory tract infections among older adults living in long-term care facilities: a systematic review and meta-analysis

BACKGROUND

Antibiotics are commonly prescribed for respiratory tract infections (RTIs) among older adults in long-term care facilities (LTCFs), and this contributes to the emergence of antimicrobial resistance. The objective of this study was to determine the antibiotic prescribing rate for RTIs among LTCF residents, and to analyse the antibiotic consumption patterns with the AwaRe monitoring tool, developed by the World Health Organization.

METHODS

MEDLINE, EMBASE and CINAHL were searched from inception to March 2022. Original articles reporting antibiotic use for RTIs in LTCFs were included in this review. Study quality was assessed using the Joanna Briggs Institute's Critical Appraisal Checklist for Prevalence Data. A random-effects meta-analysis was employed to calculate the pooled estimates. Subgroup analysis was conducted by type of RTI, country, and study start year.

RESULTS

In total, 47 articles consisting of 50 studies were included. The antibiotic prescribing rate ranged from 21.5% to 100% (pooled estimate 69.8%, 95% confidence interval 55.2-82.6%). The antibiotic prescribing rate for lower respiratory tract infections (LRTIs) was higher than the rates for viral and general RTIs. Compared with Italy, France and the USA, the Netherlands had lower antibiotic use for LRTIs. A proportion of viral RTIs were treated with antibiotics, and all the antibiotics were from the Watch group. Use of antibiotics in the Access group was higher in the Netherlands, Norway, Switzerland and Slovenia compared with the USA and Australia.

CONCLUSION

The antibiotic prescribing rate for RTIs in LTCFs was high, and AWaRe antibiotic use patterns varied by type of RTI and country. Improving antibiotic use may require coordination efforts.

The Clinical Efficacy, Safety, and Tolerability of Vancomycin for the Treatment of Recurrent Clostridioides difficile Infection - A Systematic Review

Introduction

The aim of this systematic review of randomized clinical trials (RCTs) was to examine the efficacy, safety, and tolerability of vancomycin for treatment of recurrent Clostridioides difficile infection (rCDI).

Methods

The PubMed database was searched from inception to August 23, 2022. An initial screening was performed followed by a full-text evaluation of the papers. Inclusion criteria were RCTs investigating vancomycin for treatment of rCDI.

Results

A total of six studies and 269 patients were included in the review. Three studies used a fixed dose regimen of vancomycin, one study used pulse regimen, one study used a taper-and-pulse regimen, and one study used a taper-and-pulse regimen for the participants with two or more recurrences. The resolution of infection varied from 19% to 58.3% in five of six studies reporting this as an outcome. Four out of six studies reported new episodes of rCDI as an intervention outcome, in those studies 50-63% of participants experienced rCDI. Regarding the safety and tolerability of vancomycin treatment for rCDI, one study described several adverse events regarding gastrointestinal discomfort along with fatigue and skin rash. There were no records of serious adverse events in the included studies.

Conclusion

While oral vancomycin is mostly safe and well tolerated in the RCTs reviewed here, the efficacy for treating rCDI varies greatly from 19-58.3%, and 50-63% of participants experienced new episodes of rCDI.

Gut microbiota changes associated with Clostridioides difficile infection and its various treatment strategies

Human gut microbiota are critical to both the development of and recovery from Clostridioides difficile infection (CDI). Antibiotics are the mainstay of CDI treatment, yet inherently cause further imbalances in the gut microbiota, termed dysbiosis, complicating recovery. A variety of microbiota-based therapeutic approaches are in use or in development to limit disease- and treatment-associated dysbiosis and improve rates of sustained cure. These include the recently FDA-approved fecal microbiota, live-jslm (formerly RBX2660) and fecal microbiota spores, live-brpk (formerly SER-109), which represent a new class of live biotherapeutic products (LBPs), traditional fecal microbiota transplantation (FMT), and ultra-narrow-spectrum antibiotics. Here, we aim to review the microbiome changes associated with CDI as well as a variety of microbiota-based treatment approaches.

Association of fluoroquinolones or cephalosporin plus macrolide with Clostridioides difficile infection (CDI) after treatment for community-acquired pneumonia

OBJECTIVE

Clostridioides difficile infection (CDI) is the most common cause of gastroenteritis, and community-acquired pneumonia (CAP) is the most common infection treated in hospitals. American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) CAP guidelines recommend empiric therapy with a respiratory fluoroquinolone or cephalosporin plus macrolide combination, but the CDI risk of these regimens is unknown. We examined the association between each antibiotic regimen and the development of hospital-onset CDI.

METHODS

We conducted a retrospective cohort study using data from 638 US hospitals contributing administrative including 177 also contributing microbiologic data to Premier, Inc. We included adults admitted with pneumonia and discharged from July 2010 through June 2015 with a pneumonia diagnosis code who received ≥3 days of either empiric regimen. Hospital-onset CDI was defined by a diagnosis code not present on admission and positive laboratory test on day 4 or later or readmission for CDI. Mixed propensity-weighted multiple logistic regression was used to estimate the associations of CDI with antibiotic regimens.

RESULTS

Our sample included 58,060 patients treated with either cephalosporin plus macrolide (36,796 patients) or a fluoroquinolone alone (21,264 patients) and with microbiological data; 127 (0.35%) patients who received cephalosporin plus macrolide and 65 (0.31%) who received a fluoroquinolone developed CDI. After adjustment for patient demographics, comorbidities, risk factors for antimicrobial resistance, and hospital characteristics, CDI risks were similar for fluoroquinolones versus cephalosporin plus macrolide (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.70-1.38).

CONCLUSION

Among patients with CAP at US hospitals, CDI was uncommon, occurring in ∼0.33% of patients. We did not detect a significant association between the choice of empiric guideline recommended antibiotic therapy and the development of CDI.

Antibiotic-Specific Risk for Community-Acquired Clostridioides difficile Infection in the United States from 2008 to 2020

Antibiotic exposure is a crucial risk factor for community-acquired Clostridioides difficile infection (CA-CDI). However, the relative risks associated with specific antibiotics may vary over time, and the absolute risks have not been clearly established. This is a retrospective cohort study. Adults were included if they received an outpatient antibiotic prescription within the IBM MarketScan databases between 2008 and 2020. The primary exposure was an outpatient antibiotic prescription, and the receipt of doxycycline was used as the reference comparison. The primary outcome was CA-CDI, defined as the presence of an International Classification of Diseases (ICD) diagnosis code for CDI within 90 days of receiving an outpatient antibiotic prescription, and subsequent treatment for CDI. There were 36,626,794 unique patients who received outpatient antibiotics, including 11,607 (0.03%) who developed CA-CDI. Relative to doxycycline, the antibiotics conferring the highest risks for CA-CDI were clindamycin (adjusted odds ratio [aOR], 8.81; 95% confidence interval [CI], 7.76 to 10.00), cefdinir (aOR, 5.86; 95% CI, 5.03 to 6.83), cefuroxime (aOR, 4.57; 95% CI, 3.87 to 5.39), and fluoroquinolones (aOR, 4.05; 95% CI, 3.58 to 4.59). Among older patients with CA-CDI risk factors, nitrofurantoin was also associated with CA-CDI (aOR, 3.05; 95% CI, 1.92 to 4.84), with a smaller number needed to harm, compared to the fluoroquinolones. While clindamycin, cefuroxime, and fluoroquinolone use declined from 2008 to 2020, nitrofurantoin use increased by 40%. Clindamycin was associated with the greatest CA-CDI risk, overall. Among older patients with an elevated baseline risk for CA-CDI, multiple antibiotics, including nitrofurantoin, had strong associations with CA-CDI. These results may guide antibiotic selection and future stewardship efforts.

Re-establishing the utility of tetracycline-class antibiotics for current challenges with antibiotic resistance

The progressive increase in antibiotic resistance in recent decades calls for urgent development of new antibiotics and antibiotic stewardship programs to help select appropriate treatments with the goal of minimising further emergence of resistance and to optimise clinical outcomes. Three new tetracycline-class antibiotics, eravacycline, omadacycline, and tigecycline, have been approved within the past 15 years, and represent a new era in the use of tetracyclines. These drugs overcome the two main mechanisms of acquired tetracycline-class resistance and exhibit a broad spectrum of in vitro activity against gram-positive, gram-negative, anaerobic, and atypical pathogens, including many drug-resistant strains. We provide an overview of the three generations of tetracycline-class drugs, focussing on the efficacy, safety, and clinical utility of these three new third-generation tetracycline-class drugs. We also consider various scenarios of unmet clinical needs where patients might benefit from re-engagement with tetracycline-class antibiotics including outpatient treatment options, patients with known β-lactam antibiotic allergy, reducing the risk of Clostridioides difficile infection, and their potential as monotherapy in polymicrobial infections while minimising the risk of any potential drug-drug interaction. KEY MESSAGESThe long-standing safety profile and broad spectrum of activity of tetracycline-class antibiotics made them a popular choice for treatment of various bacterial infections; unfortunately, antimicrobial resistance has limited the utility of the early-generation tetracycline agents.The latest generation of tetracycline-class antibiotics, including eravacycline, tigecycline, and omadacycline, overcomes the most common acquired tetracycline resistance mechanisms.Based on in vitro characteristics and clinical data, these newer tetracycline agents provide an effective antibiotic option in the treatment of approved indications in patients with unmet clinical needs - including patients with severe penicillin allergy, with renal or hepatic insufficiency, recent Clostridioides difficile infection, or polymicrobial infections, and those at risk of drug-drug interactions.

Rate and predictors of 30-day readmission for clostridiodes difficile: a United States analysis

BACKGROUND

Clostridiodes difficile is a leading cause of healthcare-associated diarrhea. In this study, we aimed to identify the rates and predictors for 30-day readmissions of Clostridiodes difficile Enterocolitis (CDE) in the United States.

METHODS

We conducted a retrospective study of the Nationwide Readmissions Database to identify adult hospitalizations with a principal diagnosis of CDE for 2018. Individuals <18 years old and elective hospitalizations were excluded. Primary outcomes included readmission rate and the top ten principal diagnosis on readmission, while the secondary outcomes were inpatient mortality, hospital costs and independent predictors of 30-day all-cause readmissions. Furthermore, we devised a scoring system to estimate the risk of CDE readmissions. Stata® Version 16 was used for statistical analysis and p-values ≤0.05 were statistically significant.

RESULTS

We identified 94,668 index hospitalizations and 18,296 readmissions at 30-days for CDE in 2018. The 30-day all-cause readmission rate was 25.7%. On readmission, CDE was the most common principal diagnosis (25.7%), followed by unspecified sepsis, and acute renal failure. A female predominance was also noted for index and 30-day readmissions of CDE. Compared to index admissions, we noted higher odds of inpatient mortality [4.4 vs 1.4%, Odds Ratio (OR):3.32, 95% Confidence Interval (CI):2.87-3.84, p < 0.001], longer mean length of stay (LOS) [6.4 vs 5.6 days, Mean Difference (MD):0.9, 95% CI:0.7-1.0, p < 0.001), and higher mean total hospital charge (THC) [$56,015 vs $40,871, MD:15,144, 95% CI:13,260-17,027, p < 0.001] for 30-day readmissions of CDE. Independent predictors for 30-day all-cause readmissions of CDE included discharged against medical advice (AMA) [Adjusd Hazard Ratio (aHR):2.01, 95% CI:1.73-2.53, p < 0.001], diabetes mellitus (DM) [aHR:1.22, 95% CI:1.16-1.29, p < 0.001], and chronic kidney disease (CKD) [aHR:1.29, 95% CI:1.21-1.37, p < 0.001].

CONCLUSION

The all-cause 30-day readmission rate and inpatient mortality for CDE was 25.7% and 4.4%, respectively. Discharge AMA, DM and CKD were independent predictors for 30-day all-cause readmissions of CDE.KEY MESSAGEThe 30-day all-cause readmission rate for Clostridiodes difficile Enterocolitis was noted to be 21.4% in 2018.Independent predictors of 30-day all-cause readmissions for Clostridiodes difficile Enterocolitis include diabetes mellitus, discharged against medical advice and chronic kidney disease.Readmissions of Clostridiodes difficile Enterocolitis had higher mortality rates, healthcare cost and length of hospital stay compared to index admissions.

Acute Endotoxemia-Induced Respiratory and Intestinal Dysbiosis

Systemic inflammatory response syndrome (SIRS) is a severe condition characterized by systemic inflammation, which may lead to multiple organ failure, shock and death. SIRS is common in burn patients, pancreatitis and sepsis. SIRS is often accompanied by intestinal dysbiosis. However, the mechanism, role and details of microbiome alterations during the early phase of acute SIRS are not completely understood. The current study aimed to characterize the dynamic alterations of both the intestinal and respiratory microbiome at two timepoints during the early phase of acute SIRS (4 and 8 h after LPS) and link these to the host response in a mouse model of a LPS-induced lethal SIRS. Acute SIRS had no effect on the microbiome in the large intestine but induced a rapid dysbiosis in the small intestine, which resembled the microbiome alterations commonly observed in SIRS patients. Later in the disease progression, a dysbiosis of the respiratory microbiome was observed, which was associated with the MMP9 expression in the lungs. Although similar bacteria were increased in both the lung and the small intestine, no evidence for a gut-lung translocation was observed. Gut dysbiosis is commonly observed in diseases involving inflammation in the gut. However, whether the inflammatory response associated with SIRS and sepsis can directly cause gut dysbiosis was still unclear. In the current study we provide evidence that a LPS-induced SIRS can directly cause dysbiosis of the small intestinal and respiratory microbiome.

Clostridium difficile colitis portends poor outcomes in lower extremity orthopaedic trauma surgery

INTRODUCTION

Clostridium difficile is the most common cause of healthcare-associated infectious diarrhea and colitis, and carries the potential for high morbidity, particularly in frail patient populations. The purpose of this study was to utilize a large nationally representative database in order to report 1.) the incidence of CDC in patients with operative lower extremity fractures, 2.) risk factors for the development of CDC, 3.) the association of CDC with length of stay (LOS), readmission, and 30-day mortality rates.

METHODS

The ACS-NSQIP (2015-2019) was queried for patients who underwent surgical fixation of lower extremity fractures. A backward elimination multivariate regression model was used to identify risk factors for CDC. Chi squared and multivariate regression that controlled for preoperative variables and comorbidities were used to compare outcomes in patients with and without CDC.

RESULTS

95,532 patients were included, 681 (0.71%) of whom developed CDC. Risk factors for CDC were advanced age, ASA class ≥ 3, smoking, dialysis, anemia, hypoalbuminemia, preoperative SIRS, preoperative wound infections, preoperative sepsis, and the use of spinal anesthesia or MAC/IV sedation. Patients with CDC had significantly increased 30-day mortality rates (10.6% vs 4.4%; OR 1.80, 95% CI 1.41-2.31), readmission (34.2% vs 7.5%; OR 5.13, 95% CI 4.36-6.05, and length of stay (7.5 days vs 5.3 days) compared to patients without CDC.

CONCLUSION

The incidence of CDC in lower extremity orthopedic trauma patients was 0.71%. An occurrence of CDC was associated with approximately a 2.5 times increase in 30-day mortality, five times the readmission rate, and a longer hospital stay compared to patients without CDC. Mitigating the spread of c. diff through improved antibiotic stewardship and prompt treatment of CDC is paramount to decreasing the burden this infection imposes on orthopedic trauma patients and the healthcare system.

A Threshold Logistic Modelling Approach for Identifying Thresholds between Antibiotic Use and Methicillin-Resistant Staphylococcus aureus Incidence Rates in Hospitals

The aim of this study was to demonstrate the utility of threshold logistic modelling, an innovative approach in identifying thresholds and risk scores in the context of population antibiotic use associated with methicillin-resistant Staphylococcus aureus (MRSA) incidence rates in hospitals. The study also aimed to assess the impact of exceeding those thresholds that resulted in increased MRSA rates. The study was undertaken in a 700-bed hospital in England between January 2015 and December 2021 (84 monthly observations). By employing the threshold logistic modelling approach, we: (i) determined the cut-off percentile value of MRSA incidence that defines a critical level of MRSA; (ii) identified thresholds for fluoroquinolone and co-amoxiclav use that would accelerate MRSA incidence rates and increase the probability of reaching critical incidence levels; (iii) enabled a better understanding of the effect of antibiotic use on the probability of reaching a critical level of resistant pathogen incidence; (iv) developed a near real-time performance monitoring feedback system; (v) provided risk scores and alert signals for antibiotic use, with the ability to inform hospital policies, and control MRSA incidence; and (vi) provided recommendations and an example for the management of pathogen incidence in hospitals. Threshold logistic models can help hospitals determine quantitative targets for antibiotic usage and can also inform effective antimicrobial stewardship to control resistance in hospitals. Studies should work toward implementing and evaluating the proposed approach prospectively, with the aim of determining the best counter-measures to mitigate the risk of increased resistant pathogen incidence in hospitals.

Risk factors for Clostridioides difficile infection in children: A systematic review and meta-analysis

BACKGROUND

Clostridioides difficile infection (CDI) is considered an urgent threat to human health by the US Centers for Disease Control and Prevention. In recent years, C. difficile is increasingly being reported as a cause of gastrointestinal diseases in children, and the prevalence of hospital-acquired CDI (HA-CDI) and community-acquired CDI (CA-CDI) in children is increasing.

AIM

To perform a systematic review and meta-analysis of risk factors for Clostridioides difficile infection (CDI) in children.

METHODS

MEDLINE/PubMed, EMBASE, Web of Science, Scopus, OVID, China National Knowledge Infrastructure, Wanfang (Chinese), SinoMed (Chinese), and Weipu (Chinese) databases were searched from inception through January 12, 2022. Observational studies (cohort, case-control, and cross-sectional) on CDI in children were included in the analysis. Data were pooled using a fixed or random-effects model, and odds ratios (ORs) were calculated.

FINDINGS

A total of 25 observational studies were included in the analysis. Prior antibiotic exposure (OR, 1.93; 95% confidence interval (CI), 1.25-2.97), prolonged hospitalization (OR, 14.68; 95% CI, 13.24-16.28), hospitalization history (OR, 3.67; 95% CI, 1.91-7.06), gastric acid suppressants (OR, 1.96; 95% CI, 1.41-2.73), male gender (OR, 1.18; 95% CI, 1.05-1.32), neoplastic disease (OR, 3.40; 95% CI, 2.85-4.07), immunodeficiency (OR, 4.18; 95% CI, 3.25-5.37), solid organ transplantation (OR, 4.56; 95% CI, 3.95-5.27) and enteral feeding (OR, 2.21; 95% CI, 1.15-4.62) were associated with an increased risk of CDI.

CONCLUSION

This systematic review and meta-analysis provides further evidence for the susceptibility factors of CDI to improve clinicians' awareness of CDI and effectively prevent C. difficile associated diarrhoea in children.

Association between Antibiotic Use and Hospital-Onset Clostridioides difficile Infection in University Tertiary Hospital in Serbia, 2011–2021: An Ecological Analysis

This ecological study is the largest to date examining the association between rates of antibiotic use (AU) and hospital-onset (HO) Clostridioides difficile infection (CDI) in a tertiary university hospital in Serbia. There was no clear trend in the incidence of HO-CDI over time. Total utilization of antibacterials for systemic use increased from 38.57 DDD/100 bed-days (BD) in 2011 to 56.39 DDD/100 BD in 2021. The most commonly used antibiotics were third-generation cephalosporins, especially ceftriaxone, with maximum consumption in 2021 (19.14 DDD/100 BD). The share of the Access group in the total utilization of antibiotics ranged from 29.95% to 42.96% during the observed period. The utilization of the Reserve group of antibiotics indicated a statistically significant increasing trend (p = 0.034). A statistically significant difference in the consumption of medium-risk antibiotics from 2011 to 2021 was shown for penicillins and a combination of sulfamethoxazole and trimethoprim. The consumption of cefotaxime showed a statistically significant negative association with the rate of HO-CDI (r = −0.647; p = 0.031). Ampicillin and the combination of amoxicilline with clavulanic acid have shown a negative statistically significant correlation with the ID of HO-CDI (r = −0.773 and r = −0.821, respectively). Moreover, there was a statistically significant negative correlation between consumption of “medium-risk antibiotics” and the rate of HO-CDI (r = −0.677). The next challenging step for the hospital multidisciplinary team for antimicrobials is to modify the antibiotic list according to the Access, Watch, and Reserve classification, in such a way that at least 60% of the AU should be from the Access group, according to the World Health Organization recommendation.

Risk of antibiotics associated with Clostridioides difficile infection: Antibiotic stewardship in action

We examined risk associated with antibiotics used for Clostridioides difficile infection (CDI) at a single site from 2018 through 2020. Overall, 78 patients had nonrecurrent infections. Among inpatient antibiotics, intravenous meropenem had the highest CDI rate (3.56 per 1,000 days of therapy; n = 2 cases). Among outpatient antibiotics, metronidazole had the highest rate (0.071 per 1,000 pills dispensed; n = 3 cases).

Tauroursodeoxycholic Acid Inhibits Clostridioides difficile Toxin-Induced Apoptosis

C. difficile infection (CDI) is a highly inflammatory disease mediated by the production of two large toxins that weaken the intestinal epithelium and cause extensive colonic tissue damage. Antibiotic alternative therapies for CDI are urgently needed as current antibiotic regimens prolong the perturbation of the microbiota and lead to high disease recurrence rates. Inflammation is more closely correlated with CDI severity than bacterial burden, thus therapies that target the host response represent a promising yet unexplored strategy for treating CDI. Intestinal bile acids are key regulators of gut physiology that exert cytoprotective roles in cellular stress, inflammation, and barrier integrity, yet the dynamics between bile acids and host cellular processes during CDI have not been investigated. Here we show that several bile acids are protective against apoptosis caused by C. difficile toxins in Caco-2 cells and that protection is dependent on conjugation of bile acids. Out of 20 tested bile acids, taurine conjugated ursodeoxycholic acid (TUDCA) was the most potent inhibitor, yet unconjugated UDCA did not alter toxin-induced apoptosis. TUDCA treatment decreased expression of genes in lysosome associated and cytokine signaling pathways. TUDCA did not affect C. difficile growth or toxin activity in vitro whereas UDCA significantly reduced toxin activity in a Vero cell cytotoxicity assay and decreased tcdA gene expression. These results demonstrate that bile acid conjugation can have profound effects on C. difficile as well as the host and that conjugated and unconjugated bile acids may exert different therapeutic mechanisms against CDI.

Prophylactic Antibiotics in Patients with Traumatic Pneumocephalus or Cerebrospinal Fluid Leak

INTRODUCTION

Pneumocephalus and cerebrospinal fluid (CSF) leaks are uncommon after trauma, but they expose the sterile CSF to environmental pathogens and create theoretical risk of central nervous system infection (CNSI). Prophylactic antibiotics are commonly given to these patients, but there is a paucity of evidence to guide this practice. We aim to quantify the incidences of these entities and analyze the efficacy of prophylactic antibiotics in preventing CNSIs.

METHODS

A retrospective cohort study was conducted using our institutional trauma registry. All patients admitted from January 2014 to July 2020 with traumatic pneumocephalus (TP) or basilar skull fracture with CSF leak (BSF-CSF) were included. ICD-9 and ICD-10 codes were used to identify CNSIs. CNSI rates among defined prophylactic antibiotic regimens, no antibiotics, and other antibiotic regimens were evaluated. ANOVA was used to analyze differences between the groups.

RESULTS

365 patients met inclusion criteria: 360 with TP; 5 with BSF-CSF. 1.1% (4/365) of patients developed CNSI, all with isolated traumatic pneumocephalus. 1.4% of patients (1/72) without antibiotics; 1.2% (3/249) receiving IV antibiotics outside of a defined regimen; and 1.1% (1/88) on a designated prophylactic regimen developed CNSIs. ANOVA indicated the incidence of CNSI was not significantly different among patients who received antibiotics or not, regardless of the regimen (p-value 0.958).

CONCLUSION

TP and BSF-CSF are rare diagnoses among trauma patients. The rate of CNSI is marginal and antibiotics do not appear to confer a protective advantage. A larger trial is needed to elucidate the true effect of antibiotics on preventing CNSIs in patients with these uncommon diagnoses.

Identifying Antibiotic Use Targets for the Management of Antibiotic Resistance Using an Extended-Spectrum β-Lactamase-Producing Escherichia coli Case: A Threshold Logistic Modeling Approach

The aim of this study was to develop a logistic modeling concept to improve understanding of the relationship between antibiotic use thresholds and the incidence of resistant pathogens. A combined approach of nonlinear modeling and logistic regression, named threshold logistic, was used to identify thresholds and risk scores in hospital-level antibiotic use associated with hospital-level incidence rates of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli). Threshold logistic models identified thresholds for fluoroquinolones (61.1 DDD/1000 occupied bed days (OBD)) and third-generation cephalosporins (9.2 DDD/1000 OBD) to control hospital ESBL-producing E. coli incidence. The 60th percentile of ESBL-producing E. coli was determined as the cutoff for defining high incidence rates. Threshold logistic analysis showed that for every one-unit increase in fluoroquinolones and third-generation cephalosporins above 61.1 and 9.2 DDD/1000 OBD levels, the average odds of the ESBL-producing E. coli incidence rate being ≥60th percentile of historical levels increased by 4.5% and 12%, respectively. Threshold logistic models estimated the risk scores of exceeding the 60th percentile of a historical ESBL-producing E. coli incidence rate. Threshold logistic models can help hospitals in defining critical levels of antibiotic use and resistant pathogen incidence and provide targets for antibiotic consumption and a near real-time performance monitoring feedback system.

Oral fidaxomicin versus vancomycin for the treatment of Clostridioides difficile infection: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Fidaxomicin (FDX) has received considerable attention as a novel therapeutic alternative agent to vancomycin (VCM) for Clostridioides difficile infection (CDI). However, the superiority and efficacy profile of FDX are not sufficiently determined by high-quality evidence. This study aimed to clarify the superiority of FDX for CDI treatment through a systematic review and meta-analysis.

METHODS

We conducted a meta-analysis of randomized controlled trials (RCTs) which evaluated the efficacy and safety of FDX and VCM in patients with CDI. Electronic databases (PubMed, Cochrane Library, Web of Science, and Clinicaltrials.gov) were searched for studies published until October 15, 2021. The primary endpoint was global cure. The secondary endpoints were clinical cure, recurrence, and adverse event. Risk ratios (RRs), risk differences (RDs), and 95% confidence intervals were calculated using Mantel-Haenszel random-effects model. The risk of bias was assessed using Cochrane Handbook for Systematic Reviews of Interventions and Assessment Criteria.

RESULTS

Six RCTs were included in this meta-analysis. Compared to VCM, FDX was associated with significantly higher global cure rates (RR = 1.18, P < 0.00001; RD = 0.11, 95% CI = 0.07-0.16). In addition, clinical cure rates were comparable between FDX and VCM (P = 0.31). FDX was associated with significantly lower recurrence rates compared to VCM (RR = 0.59, P < 0.0001). In addition, adverse event rates were not significantly different between the drugs (P = 0.41).

CONCLUSION

FDX achieves significantly higher global cure rates and lower recurrence rates and is comparable to VCM in clinical cure rates and adverse event rates in patients with CDI. Collectively, FDX is superior to VCM as a therapeutic agent for CDI.

A unique class of Zn2+-binding serine-based PBPs underlies cephalosporin resistance and sporogenesis in Clostridioides difficile

Treatment with β-lactam antibiotics, particularly cephalosporins, is a major risk factor for Clostridioides difficile infection. These broad-spectrum antibiotics irreversibly inhibit penicillin-binding proteins (PBPs), which are serine-based enzymes that assemble the bacterial cell wall. However, C. difficile has four different PBPs (PBP1-3 and SpoVD) with various roles in growth and spore formation, and their specific links to β-lactam resistance in this pathogen are underexplored. Here, we show that PBP2 (known to be essential for vegetative growth) is the primary bactericidal target for β-lactams in C. difficile. PBP2 is insensitive to cephalosporin inhibition, and this appears to be the main basis for cephalosporin resistance in this organism. We determine crystal structures of C. difficile PBP2, alone and in complex with β-lactams, revealing unique features including ligand-induced conformational changes and an active site Zn2+-binding motif that influences β-lactam binding and protein stability. The Zn2+-binding motif is also present in C. difficile PBP3 and SpoVD (which are known to be essential for sporulation), as well as in other bacterial taxa including species living in extreme environments and the human gut. We speculate that this thiol-containing motif and its cognate Zn2+ might function as a redox sensor to regulate cell wall synthesis for survival in adverse or anaerobic environments.

Impact of targeted intervention using a collaborative approach for oral third-generation cephalosporins: An interrupted time-series analysis

OBJECTIVES

To assess the effectiveness of a targeted intervention using a collaborative approach, added to a comprehensive educational intervention, to facilitate the appropriate use of oral third-generation cephalosporins (3GCs).

DESIGN

Quasi-experimental study.

SETTING

The University of Tokyo Hospital, a tertiary-care teaching hospital.

PARTICIPANTS

Approximately 2,000,000 outpatients and 80,000 inpatients at the hospital between April 2017 and March 2020.

INTERVENTION

The targeted intervention using the collaborative approach was implemented in the departments with the highest use of oral 3GCs (ophthalmology and dermatology departments). Interrupted time-series analysis was applied to assess the change in days of therapy (DOT) of oral 3GCs between the preintervention period (April 2017-April 2019) and the postintervention period (May 2019-March 2020) for both inpatients and outpatients.

RESULTS

After the introduction of the targeted intervention with oral 3GCs, a significant immediate reduction of 13.48 DOT per 1,000 patient days was detected in inpatients (P < .001). However, no significant change in slope was observed before and after the intervention (-0.02 DOT per 1,000 patient days per month; P = .94). Although a temporary increase was observed after the targeted intervention in outpatients, the slope significantly decreased (-0.69 DOT per 1,000 outpatient visits per month; P = .044). No differences were observed in the use of other oral antibiotics after the intervention.

CONCLUSIONS

The targeted intervention contributed to a reduction in DOT of oral 3GCs in both inpatients and outpatients. Targeted interventions using a collaborative approach might be helpful in further decreasing the inappropriate use of antibiotics.

Antimicrobial safety considerations in critically ill patients: part II: focused on anti-microbial toxicities

INTRODUCTION

Antibiotic prescription is a challenging issue in critical care settings. Different pharmacokinetic and pharmacodynamic properties, polypharmacy, drug interactions, and high incidence of multidrug-resistant microorganisms in this population can influence the selection, safety, and efficacy of prescribed antibiotics.

AREAS COVERED

In the current article we searched PubMed, Scopus and Google Scholar for neurotoxicities, hematologic toxicity and fluid stewardship in intensive care units.

EXPERT OPINION

Critically ill patients who receive antimicrobial agents should be monitored for neurological, hematologic toxicities especially seizure, thrombocytopenia, and clostridioides infections. Other toxicities including QTc prolongation, electrolyte disturbances, liver enzyme elevation, and infusion-related reactions were being considered. Other changes, including fluid overload, hypoalbuminemia, augmented renal clearance, increased cardiac outputs in septic shock, and acute kidney injury, may influence treatment efficiency and patient outcome.

Optimizing antibiotic therapies to reduce the risk of bacterial resistance

The incidence of infections caused by bacteria that are resistant to antibiotics is constantly increasing. In Europe alone, it has been estimated that each year about 33'000 deaths are attributable to such infections. One important driver of antimicrobial resistance is the use and abuse of antibiotics in human medicine. Inappropriate prescribing of antibiotics is still very frequent: up to 50% of all antimicrobials prescribed in humans might be unnecessary and several studies show that at least 50% of antibiotic treatments are inadequate, depending on the setting. Possible strategies to optimize antibiotic use in everyday clinical practice and to reduce the risk of inducing bacterial resistance include: the implementation of rapid microbiological diagnostics for identification and antimicrobial susceptibility testing, the use of inflammation markers to guide initiation and duration of therapies, the reduction of standard durations of antibiotic courses, the individualization of antibiotic therapies and dosing considering pharmacokinetics/pharmacodynamics targets, and avoiding antibiotic classes carrying a higher risk for induction of bacterial resistance. Importantly, measures to improve antibiotic prescribing and antibiotic stewardship programs should focus on facilitating clinical reasoning and improving prescribing environment in order to remove any barriers to good prescribing.

Activation of the Extracytoplasmic Function σ Factor σV in Clostridioides difficile Requires Regulated Intramembrane Proteolysis of the Anti-σ Factor RsiV

Clostridioides (Clostridium) difficile is one of the leading causes of nosocomial diarrhea. Lysozyme is a common host defense against many pathogenic bacteria. C. difficile exhibits high levels of lysozyme resistance, which is due in part to the extracytoplasmic functioning (ECF) σ factor, σ^V. It has been previously demonstrated that genes regulated by σ^V are responsible for peptidoglycan modifications that provide C. difficile with high lysozyme resistance. σ^V is not unique to C. difficile however, and its role in lysozyme resistance and its mechanism of activation has been well characterized in Bacillus subtilis where the anti-σ, RsiV, sequesters σ^V until lysozyme directly binds to RsiV, activating σ^V. However, it remains unclear if the mechanism of σ^V activation is similar in C. difficile. Here, we investigated how activation of σ^V is controlled in C. difficile by lysozyme. We found that C. difficile RsiV was degraded in the presence of lysozyme. We also found that disruption of a predicted signal peptidase cleavage site blocked RsiV degradation and σ^V activation, indicating that the site-1 protease is likely a signal peptidase. We also identified a conserved site-2 protease, RasP, that was required for site-2 cleavage of RsiV and σ^V activation in response to lysozyme. Combined with previous work showing RsiV directly binds lysozyme, these data suggested that RsiV directly binds lysozyme in C. difficile, which leads to RsiV destruction via cleavage at site-1 by signal peptidase and then at site-2 by RasP, ultimately resulting in σ^V activation and increased resistance to lysozyme. IMPORTANCE Clostridioides difficile is a major cause of hospital-acquired diarrhea and represents an urgent concern due to the prevalence of antibiotic resistance and the rate of recurrent infections. We previously showed that σ^V and the regulon under its control were involved in lysozyme resistance. We have also shown in B. subtilis that the anti-σ RsiV acts as a direct sensor for lysozyme. which results in the destruction of RsiV and activation of σ^V. Here, we described the proteases required for degradation of RsiV in C. difficile in response to lysozyme. Our data indicated that the mechanism is highly conserved between B. subtilis and C. difficile.

Assessment of the Transmission Dynamics of Clostridioides difficile in a Farm Environment Reveals the Presence of a New Toxigenic Strain Connected to Swine Production

The recent increase in community-acquired Clostridioides difficile infections discloses the shift in this bacterium epidemiology. This study aimed at establishing a transmission network involving One Health components, as well as assessing the zoonotic potential and genomic features of dominant clones. Samples were collected from different compartments of animal, human and environmental origin, from an animal production unit. C. difficile isolates were characterized for toxigenic profile by multiplex-PCR, while genetic diversity was evaluated by PCR-ribotyping and whole genome-based analysis. The overall C. difficile prevalence was 37.2% (70/188), and included samples from environmental (58.3%, 35/60) and animal (31.5%, 35/111) compartments; human samples (n = 17) taken from healthy workers were negative. A predominant clone from RT033 was found in almost 90% of the positive samples, including samples from all compartments connected to the pig production unit, with core-genome single nucleotide variant (SNV)-based Analysis supporting a clonal transmission between them (mean distance of 0.1 ± 0.1 core-SNVs). The isolates from this clone (herein designated PT RT033) were positive for all C. difficile toxin genes (tcdA, tcdB, cdtA/cdtB). The phyloGenetic positioning of this clone was clearly distinct from the classical RT033 cluster, suggesting a different evolutionary route. This new clone shares genomic features with several RTs from the clade 5 Sequence Type (ST) 11, including a complete pathogenicity locus (PaLoc) that is more similar to the one found in toxigenic strains and contrasting to the less virulent classical RT033 (tcdA-, tcdB-, cdtA + /cdtB +). The presence of a tcdA gene truncated into two ORFs, not previously described, requires further evaluation concerning toxin functionality. We hypothesize that the unique combination of genetic elements found in the PT RT033 clone may contribute to host tropism and environmental dissemination and maintenance. This study constitutes the first report of a toxigenic RT033 clone and adds to the overall knowledge on Clade 5 sequence type 11, considered the C. difficile evolutionary lineage with the highest zoonotic potential. The presence of this clone in all compartments associated with the pig production unit suggests a transmission chain involving these animals and contributes to unveil the role played by animal and environmental reservoirs in this pathogen epidemiology.

Clostridioides difficile infection in Africa: A narrative review

Clostridioides (Clostridium) difficile infection (CDI) places a burden on healthcare facilities worldwide. Most research studies have been concentrated in high-income countries in North America, Europe, Asia and Australia, where C. difficile is the leading cause of diarrhoea associated with antimicrobial use. This narrative review summarises African CDI studies, focussing on reports published in the last 20 years. Although relatively sparse, the data suggest that CDI is an important cause of diarrhoea on the continent. African CDI patient populations are often younger than in European and North American settings, probably due to the high prevalence of co-morbid conditions such as tuberculosis, particularly in sub-Saharan Africa. Strain typing data are rare and where reported generally limited to single sites and institutions. Despite challenges, including a lack of facilities and awareness, there is a need for further investigation to more accurately determine the true burden of disease caused by C. difficile in Africa.

Association between antiulcer agents and Clostridioides difficile infection in patients receiving antibiotics: A retrospective cohort study using the diagnosis procedure combination database in Japan

OBJECTIVES

To evaluate baseline risk for hospital onset Clostridioides difficile infection (HO-CDI) and the association with the use of antiulcer agents among patients undergoing antibiotic therapy in Japan.

METHODS

We conducted a retrospective cohort study using Japanese Diagnosis Procedure Combination database. Between July 2018 and January 2019, patients aged ≥18 years were included if they started antibiotics within two days of hospital admission. We defined exposure as proton pump inhibitors or histamine 2 receptor antagonists starting from day 2 to day 4 and the primary outcome as HO-CDI within 30 days. We performed multivariable analyses with complete cases using the propensity score (inverse probability treatment weighting [IPTW]) and several sensitivity analyses.

RESULTS

In total, 87,137 patients were included. The median age was 78 years; 52.0% were men, and 23.6% received antiulcer agents. Within 30 days of admission, HO-CDI were observed in 0.41% and 0.26% of the antiulcer agent and control groups, respectively. IPTW revealed a positive association between antiulcer agents and HO-CDI (adjusted odds ratio, 1.33; 95% confidence interval [CI]: 1.13, 1.56). In the IPTW method, the risk difference was smaller (0.09%, 95% CI: 0.04%, 0.15%).

CONCLUSION

The use of antiulcer agents in patients with antibiotics was associated with HO-CDI in Japan. However, the baseline risk and the difference in HO-CDI event rates were small; thus, as per several clinical practice guidelines, it is important to monitor antiulcer agent use and discontinue unnecessary use. The baseline risk should be considered when clinically evaluating the association between antiulcer agents and HO-CDI.

Association between consumption of antibiotics, infection control interventions and Clostridioides difficile infections: Analysis of six-year time-series data in a tertiary-care hospital in Greece

BACKGROUND

To investigate the association between Clostridioides difficile infection (CDI), antibiotic use, and infection control interventions, during an antibiotic stewardship program (ASP) implemented in a tertiary-care hospital in Greece from 2013 to 2018.

METHODS

Analysis was applied for the following monthly indices: 1. consumption of antibiotics; 2. use of hand hygiene disinfectant solutions; 3. percentage of isolations of patients either with multidrug-resistant (MDR) bacteria, or CDI, or admitted from another hospital; and 4. percentage of patients with CDI divided into two groups: community-acquired CDI (CACDI) and hospital-associated CDI (HACDI) (onset ≤72 h and >72 h after admission, respectively).

RESULTS

During the study, a significant reduction in CACDI rate from 0.3%/admissions [95% CI 0.1-0.6] to 0.1%/admissions [95% CI 0.0-0.3] (p-value = 0.035) was observed in adults ICU, while CDI rates were stable in the rest of the hospital. Antibiotic consumption showed a significant reduction in total hospital, from 91.7 DDDs [95% CI 89.7-93.7] to 80.1 DDDs [95% CI 79.1-81.1] (p-value<0.001), except adults ICU. Non-advanced antibiotics correlated with decreased CDI rates in Adults Clinic Departments and ICU. Isolation of patients one and two months earlier correlated with decreased CACDI rates per 20% [95% CI 0.64-1.00, p-value = 0.046] and HACDI per 23% [95% CI 0.60-1.00, p-value = 0.050] in Adults Clinic Departments. Consumption of disinfectant solutions current month correlated with decreased rate for CACDI per 33% [95% CI 0.49-0.91, p-value = 0.011] and HACDI per 38% [95% CI 0.40-0.98, p-value = 0.040] in total Hospital Clinics.

CONCLUSION

Rational antibiotic prescribing during ASP along with multipronged intervention strategy focusing on hand hygiene and patient isolation measures prevent and control CDI outbreaks in the hospital setting.

Association of Exposure to High-risk Antibiotics in Acute Care Hospitals With Multidrug-Resistant Organism Burden in Nursing Homes

IMPORTANCE

Little is known about the contribution of hospital antibiotic prescribing to multidrug-resistant organism (MDRO) burden in nursing homes (NHs).

OBJECTIVES

To characterize antibiotic exposures across the NH patient's health care continuum (preceding health care exposure and NH stay) and to investigate whether recent antibiotic exposure is associated with MDRO colonization and room environment contamination at NH study enrollment.

DESIGN, SETTING, AND PARTICIPANTS

This is a secondary analysis of a prospective cohort study (conducted from 2013-2016) that enrolled NH patients and followed them up for as long as 6 months. The study was conducted in 6 NHs in Michigan among NH patients who were enrolled within 14 days of admission. Clinical metadata abstraction, multi-anatomical site screening, and room environment surveillance for MDROs were conducted at each study visit. Data were analyzed between May 2019 and November 2021.

EXPOSURES

Antibiotic data were abstracted from NH electronic medical records by trained research staff and characterized by class, route, indication, location of therapy initiation, risk for Clostridioides difficile infection (C diffogenic agents), and 2019 World Health Organization Access, Watch, and Reserve (AWARE) antibiotic stewardship framework categories.

MAIN OUTCOMES AND MEASURES

The primary outcomes were MDRO colonization and MDRO room environment contamination at NH study enrollment, measured using standard microbiology methods. Multivariable logistic regression was used to identify whether antibiotic exposure within 60 days was associated with MDRO burden at NH study enrollment. Additionally, antibiotic exposure data were characterized using descriptive statistics.

RESULTS

A total of 642 patients were included (mean [SD] age, 74.7 [12.2] years; 369 [57.5%] women; 402 [62.6%] White; median [IQR] NH days to enrollment, 6.0 [3.0-7.0]). Of these, 422 (65.7%) received 1191 antibiotic exposures: 368 (57.3%) received 971 hospital-associated prescriptions, and 119 (18.5%) received 198 NH-associated prescriptions. Overall, 283 patients (44.1%) received at least 1 C diffogenic agent, and 322 (50.2%) received at least 1 high-risk WHO AWARE antibiotic (watch or reserve agent). More than half of NH patients (364 [56.7%]) and room environments (437 [68.1%]) had MDRO-positive results at enrollment. In multivariable analysis, recent antibiotic exposure was positively associated with baseline MDRO colonization (odds ratio [OR], 1.70; 95% CI, 1.22-2.38) and MDRO environmental contamination (OR, 1.67; 95% CI, 1.17-2.39). Exploratory stratification by C diffogenic agent exposure increased the effect size (MDRO colonization: OR, 1.99; 95% CI, 1.33-2.96; MDRO environmental contamination: OR, 1.86; 95% CI, 1.24-2.79). Likewise, exploratory stratification by exposure to high-risk WHO AWARE antibiotics increased the effect size (MDRO colonization: OR, 2.32; 95% CI, 1.61-3.36; MDRO environmental contamination: OR, 1.86; 95% CI, 1.26-2.75).

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that high-risk, hospital-based antibiotics are a potentially high-value target to reduce MDROs in postacute care NHs. This study underscores the potential utility of integrated hospital and NH stewardship programming on regional MDRO epidemiology.

The Role of Targeted Versus Standard Antibiotic Prophylaxis in Pancreatoduodenectomy in Reducing Postoperative Infectious Complications: A Systematic Review and Meta-analysis

INTRODUCTION

Infectious complications are common after pancreatoduodenectomy, which in turn are associated with preoperative biliary drainage. Current guidelines recommend a first-generation cephalosporin as perioperative antibiotic prophylaxis. However, some studies support the use of targeted antibiotics. The aim of this systematic review and meta-analysis is to evaluate the role of prophylactic targeted antibiotics compared to standard antibiotics in reducing postoperative infections after pancreatoduodenectomy.

METHODS

A search from MEDLINE, EMBASE, and Cochrane library from 1946 to July 2020 was conducted. Studies were included if they compared targeted antibiotics with standard perioperative antibiotics while including outcome data on surgical site infections (SSI). Targeted therapy was defined as perioperative antibiotics targeting organisms prevalent in bile instrumentation or by culture data obtained from the patient or institution. Outcomes assessed were the rate of SSIs and their microbiology profile. Analyses included demographic data, perioperative antibiotics, postoperative outcomes including microbiology data, and meta-analysis was performed where applicable.

RESULTS

Seven studies were included, with a total of 849 patients undergoing pancreatoduodenectomy. Targeted antibiotics were associated with a significantly lower rate of postoperative SSI compared to standard antibiotic therapy [21.1% vs 41.9%; risk ratios (RR) 0.55, 95% confidence interval 0.37-0.81]. Wound/incisional site infections and organ space infections were lower in patients receiving targeted antibiotic prophylaxis (RR 0.33, P = 0.0002 and RR 0.54, P = 0.0004, respectively). Enterococcus species were the most common bacteria reported.

CONCLUSION

There was a significant reduction in overall SSI rates when targeted antibiotics was used. Current standard antibiotic prophylaxis is inadequate in covering microbes prevalent in postoperative infections developing after pancreatoduodenectomy.

In Silico Identification and Experimental Validation of Peptide-Based Inhibitors Targeting Clostridium difficile Toxin A

Clostridium difficile infection is mediated by two major exotoxins: toxins A (TcdA) and B (TcdB). Inhibiting the biocatalytic activities of these toxins with targeted peptide-based drugs can reduce the risk of C. difficile infection. In this work, we used a computational strategy that integrates a peptide binding design (PepBD) algorithm and explicit-solvent atomistic molecular dynamics simulation to determine promising toxin A-targeting peptides that can recognize and bind to the catalytic site of the TcdA glucosyltransferase domain (GTD). Our simulation results revealed that two out of three in silico discovered peptides, viz. the neutralizing peptides A (NPA) and B (NPB), exhibit lower binding free energies when bound to the TcdA GTD than the phage-display discovered peptide, viz. the reference peptide (RP). These peptides may serve as potential inhibitors against C. difficile infection. The efficacy of the peptides RP, NPA, and NPB to neutralize the cytopathic effects of TcdA was tested in vitro in human jejunum cells. Both phage-display peptide RP and in silico peptide NPA were found to exhibit strong toxin-neutralizing properties, thereby preventing the TcdA toxicity. However, the in silico peptide NPB demonstrates a relatively low efficacy against TcdA.

Prevalence and antimicrobial resistance pattern of Clostridium difficile among hospitalized diarrheal patients: A systematic review and meta-analysis

Background

Clostridium difficile is the leading cause of infectious diarrhea that develops in patients after hospitalization during antibiotic administration. It has also become a big issue in community-acquired diarrhea. The emergence of hypervirulent strains of C. difficile poses a major problem in hospital-associated diarrhea outbreaks and it is difficult to treat. The antimicrobial resistance in C. difficile has worsened due to the inappropriate use of broad-spectrum antibiotics including cephalosporins, clindamycin, tetracycline, and fluoroquinolones together with the emergence of hypervirulent strains.

Objective

To estimate the pooled prevalence and antimicrobial resistance pattern of C. difficile derived from hospitalized diarrheal patients, a systematic review and meta-analysis was performed.

Methods

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline was followed to review published studies conducted. We searched bibliographic databases from PubMed, Scopus, Google Scholar, and Cochrane Library for studies on the prevalence and antimicrobial susceptibility testing on C. difficile. The weighted pooled prevalence and resistance for each antimicrobial agent was calculated using a random-effects model. A funnel plot and Egger’s regression test were used to see publication bias.

Results

A total of 15 studies were included. Ten articles for prevalence study and 5 additional studies for antimicrobial susceptibility testing of C. difficile were included. A total of 1967/7852 (25%) C. difficile were isolated from 10 included studies for prevalence study. The overall weighted pooled proportion (WPP) of C. difficile was 30% (95% CI: 10.0–49.0; p<0.001). The analysis showed substantial heterogeneity among studies (Cochran’s test = 7038.73, I2 = 99.87%; p<0.001). The weighed pooled antimicrobial resistance (WPR) were: vancomycin 3%(95% CI: 1.0–4.0, p<0.001); metronidazole 5%(95% CI: 3.0–7.0, p<0.001); clindamycin 61%(95% CI: 52.0–69.0, p<0.001); moxifloxacin 42%(95% CI: 29–54, p<0.001); tetracycline 35%(95% CI: 22–49, p<0.001); erythromycin 61%(95% CI: 48–75, p<0.001) and ciprofloxacin 64%(95% CI: 48–80; p< 0.001) using the random effect model.

Conclusions

A higher weighted pooled prevalence of C. difficile was observed. It needs a great deal of attention to decrease the prevailing prevalence. The resistance of C. difficile to metronidazole and vancomycin was low compared to other drugs used to treat C. difficile infection. Periodic antimicrobial resistance monitoring is vital for appropriate therapy of C. difficile infection.

Clostridioides difficile infection and One Health: An Equine Perspective

Clostridioides (Clostridium) difficile presents a significant health risk to humans and animals. The complexity of the bacterial–host interaction affecting pathogenesis and disease development creates an ongoing challenge for epidemiological studies, control strategies and prevention planning. The recent emergence of human disease caused by strains of C. difficile found in animals adds to mounting evidence that C. difficile infection (CDI) may be a zoonosis. In equine populations, C. difficile is a known cause of diarrhoea and gastrointestinal inflammation, with considerable mortality and morbidity. This has a significant impact on both the well‐being of the animal and, in the case of performance and production animals, it may have an adverse economic impact on relevant industries. While C. difficile is regularly isolated from horses, many questions remain regarding the impact of asymptomatic carriage as well as optimization of diagnosis, testing and treatment. This review provides an overview of our understanding of equine CDI while also identifying knowledge gaps and the need for a holistic One Health approach to a complicated issue.

Clostridioides difficile: Current overview and future perspectives

The most common world-wide cause of antibiotic-associated infectious diarrhea and colitis is the toxin producing bacterium, Clostridioides difficile (C. difficile). Here we review the background and characteristics of the bacterium and the toxins produced together with the epidemiology and the complex pathogenesis that leads to a broad clinical spectrum of disease. The review describes the difficulties faced in obtaining a quick and accurate diagnosis despite the range of sensitive and specific diagnostic tools available. We also discuss the problem of disease recurrence and the importance of disease prevention. The high rates of infection recurrence mean that treatment strategies are constantly under review and we outline the diverse treatment options that are currently in use and explore the emerging treatment options of pulsed antibiotic use, microbial replacement therapies and the use of monoclonal antibodies. We summarize the future direction of treatment strategies which include the development of novel antibiotics, the administration of oral polyclonal antibody formulations, the use of vaccines, the administration of competitive non-toxigenic spores and the neutralization of antibiotics at the microbiota level. Future successful treatments will likely involve a combination of therapies to provide the most effective and robust approach to C. difficile management.

The role of the microbiota in the management of intensive care patients

The composition of the gut microbiota is highly dynamic and changes according to various conditions. The gut microbiota mainly includes difficult-to-cultivate anaerobic bacteria, hence knowledge about its composition has significantly arisen from culture-independent methods based on next-generation sequencing (NGS) such as 16S profiling and shotgun metagenomics. The gut microbiota of patients hospitalized in intensive care units (ICU) undergoes many alterations because of critical illness, antibiotics, and other ICU-specific medications. It is then characterized by lower richness and diversity, and dominated by opportunistic pathogens such as Clostridioides difficile and multidrug-resistant bacteria. These alterations are associated with an increased risk of infectious complications or death. Specifically, at the time of writing, it appears possible to identify distinct microbiota patterns associated with severity or infectivity in COVID-19 patients, paving the way for the potential use of dysbiosis markers to predict patient outcomes. Correcting the microbiota disturbances to avoid their consequences is now possible. Fecal microbiota transplantation is recommended in recurrent C. difficile infections and microbiota-protecting treatments such as antibiotic inactivators are currently being developed. The growing interest in the microbiota and microbiota-associated therapies suggests that the control of the dysbiosis could be a key factor in the management of critically ill patients. The present narrative review aims to provide a synthetic overview of microbiota, from healthy individuals to critically ill patients. After an introduction to the different techniques used for studying the microbiota, we review the determinants involved in the alteration of the microbiota in ICU patients and the latter's consequences. Last, we assess the means to prevent or correct microbiota alteration.

The potential of microbiome replacement therapies for Clostridium difficile infection

PURPOSE OF REVIEW

There is a paradox when treating Clostridium difficile infection (CDI); treatment antibiotics reduce C. difficile colonization but cause further microbiota disruption and can lead to recurrent disease. The success of faecal microbiota transplants (FMT) in treating CDI has become a new research area in microbiome restorative therapies but are they a viable long-term treatment option?

RECENT FINDINGS

C. difficile displays metabolic flexibility to use different nutritional sources during CDI. Using microbiome therapies for the efficient restoration of bile homeostasis and to reduce the bioavailability of preferential nutrients will target the germination ability of C. difficile spores and the growth rate of vegetative cells. Several biotechnology companies have developed microbiome therapeutics for treating CDI, which are undergoing clinical trials.

SUMMARY

There is confidence in using restorative microbiome therapies for treating CDI after the demonstrated efficacy of FMT, where several biotechnology companies are aiming to supply what would be a 'first in class' treatment option. Efficient removal of C. difficile from the different intestinal biogeographies should be considered in future microbiome therapies. With the gut microbiota implicated in different diseases, more work is needed to assess the long-term consequences of microbiome therapies.

Impact of hospital antibiotic use on patient-level risk of death among 36,124,372 acute and medical admissions in England

OBJECTIVES

Initiatives to curb hospital antibiotic use might be associated with harm from under-treatment. We examined the extent to which variation in hospital antibiotic prescribing is associated with mortality risk in acute/general medicine inpatients.

METHODS

This ecological analysis examined Hospital Episode Statistics from 36,124,372 acute/general medicine admissions (≥16y) to 135 acute hospitals in England, 01/April/2010-31/March/2017. Random-effects meta-regression was used to investigate whether heterogeneity in adjusted 30-day mortality was associated with hospital-level antibiotic use, measured in defined-daily-doses (DDD)/1,000 bed-days. Models also considered DDDs/1,000 admissions and DDDs for narrow-spectrum/broad-spectrum antibiotics, parenteral/oral, and local interpretations of World Health Organization Access, Watch, and Reserve antibiotics.

RESULTS

Hospital-level antibiotic DDDs/1,000 bed-days varied 15-fold with comparable variation in broad-spectrum, parenteral, and Reserve antibiotic use. After extensive adjusting for hospital case-mix, the probability of 30-day mortality changed -0.010% (95% CI: -0.064,+0.044) for each increase of 500 hospital-level antibiotic DDDs/1,000 bed-days. Analyses of other metrics of antibiotic use showed no consistent association with mortality risk.

CONCLUSIONS

We found no evidence that wide variation in hospital antibiotic use is associated with adjusted mortality risk in acute/general medicine inpatients. Using low-prescribing hospitals as benchmarks could help drive safe and substantial reductions in antibiotic consumption of up-to one-third in this population.

The use of first-generation cephalosporin antibiotics, cefalexin and cefradine, is not associated with induction of simulated Clostridioides difficile infection

OBJECTIVES

The use of broad-spectrum cephalosporins is associated with induction of Clostridioides difficile infection (CDI). Recent knowledge on the importance of the healthy microbiota in preventing pathogen colonization/outgrowth highlights the caution needed when prescribing broad-spectrum antibiotics. The use of historical narrow-spectrum antibiotics, such as first-generation cephalosporins, is gaining increased attention once more as they have a reduced impact on the microbiota whilst treating infections. Here, the effects of two first-generation cephalosporins, compared with a third-generation cephalosporin, on the human microbiota were investigated and their propensity to induce simulated CDI.

METHODS

Three in vitro chemostat models, which simulate the physiochemical conditions of the human colon, were seeded with a human faecal slurry and instilled with either narrow-spectrum cephalosporins, cefalexin and cefradine, or a broad-spectrum cephalosporin, ceftriaxone, at concentrations reflective of colonic levels.

RESULTS

Instillation of cefalexin was associated with reduced recoveries of Bifidobacterium and Enterobacteriaceae; however, Clostridium spp. recoveries remained unaffected. Cefradine exposure was associated with decreased recoveries of Bifidobacterium spp., Bacteroides spp. and Enterobacteriaceae. These changes were not associated with induction of CDI, as we observed a lack of C. difficile spore germination/proliferation, thus no toxin was detected. This is in contrast to a model exposed to ceftriaxone, where CDI was observed.

CONCLUSIONS

These model data suggest that the minimal impact of first-generation cephalosporins, namely cefalexin and cefradine, on the intestinal microbiota results in a low propensity to induce CDI.

Patients with Clostridium difficile infection and prior appendectomy may be prone to worse outcomes

BACKGROUND

Clostridium difficile infection (CDI) occurs due to a dysbiosis in the colon. The appendix is considered a ‘safe house’ for gut microbiota and may help repopulate gut flora of patients with CDI.

AIM

To study the impact of prior appendectomy on the severity and outcomes of CDI.

METHODS

We retrospectively reviewed data of 1580 patients with CDI, admitted to our hospital between 2008 to 2018. Patients were grouped based on the presence or absence of the appendix. The primary aim was to (1) assess all-cause mortality and (2) the severity of CDI. Severity was defined as per the Infectious Diseases Society of America criteria. Logistic regression, and propensity score analysis using inverse probability of treatment weights (IPTW) was performed.

RESULTS

Of the 1580 patients, 12.5% had a history of appendectomy. There was no statistical difference in mortality between patients with a prior appendectomy or without (13.7% vs 14%, P = 0.877). However, a history of appendectomy affected the severity of CDI [odds ratio (OR) = 1.32, 95% confidence interval: 1.01-1.75]. On IPTW, this association remained significant (OR = 1.59, P < 0.05). On multivariable analysis of secondary outcomes, prior appendectomy was also associated with toxic megacolon (OR = 5.37, P < 0.05) and colectomy (OR = 2.77, P < 0.05).

CONCLUSION

Prior appendectomy may affect the severity of CDI, development of toxic megacolon and the eventual need for colectomy. Since treatment of CDI is governed by its severity, stronger antibiotic regimens or earlier use of fecal microbiota transplant may be a viable option for patients with prior appendectomy.

Integrating gut microbiome and host immune markers to understand the pathogenesis of Clostridioides difficile infection

Clostridioides difficile (C.difficile) infection is the most common cause of healthcare-associated infection and an important cause of morbidity and mortality among hospitalized patients. A comprehensive understanding of C.difficile infection (CDI) pathogenesis is crucial for disease diagnosis, treatment, and prevention. Here, we characterized gut microbial compositions and a broad panel of innate and adaptive immunological markers in 243 well-characterized human subjects (including 187 subjects with both microbiota and immune marker data), who were divided into four phenotype groups: CDI, Asymptomatic Carriage, Non-CDI Diarrhea, and Control. We found that the interactions between gut microbiota and host immune markers are very sensitive to the status of C.difficile colonization and infection. We demonstrated that incorporating both gut microbiome and host immune marker data into classification models can better distinguish CDI from other groups than can either type of data alone. Our classification models display robust diagnostic performance to differentiate CDI from Asymptomatic carriage (AUC~0.916), Non-CDI Diarrhea (AUC~0.917), or Non-CDI that combines all other three groups (AUC~0.929). Finally, we performed symbolic classification using selected features to derive simple mathematic formulas that explicitly quantify the interactions between the gut microbiome and host immune markers. These findings support the potential roles of gut microbiota and host immune markers in the pathogenesis of CDI. Our study provides new insights for a microbiome-immune marker-derived signature to diagnose CDI and design therapeutic strategies for CDI.