Predictive factors, outcomes, and molecular epidemiology of Clostridioides difficile diarrhea in Brazilian hospitals

Little is known about the role of lineage of strains of Clostridioides difficile (CD) on the clinical presentation of CD infection (CDI) in Latin America, especially regarding the treatment response. We conducted a multicenter, prospective study to investigate the predictive factors and treatment outcomes of CDI in hospitalized patients and to performed phenotypical and molecular characterization of CD strains. A total of 361 diarrheic patients at 5 hospitals from different regions of the country were enrolled. All stool samples were tested for glutamate dehydrogenase (GDH), toxins A and B, and toxin genes using a nucleic acid amplification test (NAAT). Specimens were cultured and susceptibility profile and whole-genome sequencing (WGS) were performed. CDI positivity was 15% (56/377). Predictive factors for CDI were prior use of meropenem (OR 4.09, 95% CI 2.097-7.095; p<0.001), mucus in stools (OR 3.29; 95% CI 1.406-7.722; p=0.006) and neutrophil left-shift with >20% of bands (OR 3.77; 95% IC 1.280-11.120; p=0.016). Overall mortality was 19%, with no deaths attributed to CDI. Oral metronidazole was used in 74% of cases, with 85% of cure and 14% of recurrence. A total of 35 CD isolates were recovered, all of them susceptible to metronidazole and vancomycin. The WGS revealed 17 different STs, six of which were novel. ST42 was the most common ST and hypervirulent strains were not found. Severe CDI were caused by ST42, ST5, ST8, ST48, ST33 and a novel ST667. The ermB gene was more frequently found in isolates of ST42 (p=0.004).

Impact of coexisting pneumonia in the patients admitted with Clostridium difficile infection: a retrospective study from a national inpatient database

Clostridium difficile is a gram-positive anaerobic spore forming bacillus that can cause infection in a setting of antibiotic use. Pneumonia is a major cause of morbidity and mortality in an inpatient setting and is frequently associated with significant antibiotic administration. This study aims to compare the outcomes of C. difficile infection (CDI) with and without pneumonia to determine the impact of pneumonia in hospitalized patients with CDI. This population-based retrospective observational propensity matched analysis study uses data from the National Inpatient Sample database for the years 2016 and 2017. The primary outcomes were in-hospital mortality, total hospital charges, and mean length of stay. Secondary outcomes were the rates of sepsis, septic shock, non-ST elevation myocardial infarction (NSTEMI), acute renal failure, deep vein thrombosis, and pulmonary embolism. In-hospital mortality was noted to be higher in patients with pneumonia than those without (6.5% vs 1.2%, adjusted OR (aOR) 3.85; 95% CI 2.90 to 5.11, p<0.001). The following outcomes were more prevalent in patients with pneumonia compared with those without pneumonia: sepsis (9.8% vs 1.8%, aOR 4.69, 95% CI 3.73 to 5.87, p<0.001), septic shock (4.0% vs 0.5%, aOR 6.32, 95% CI 4.43 to 9.03, p<0.001), NSTEMI (1.9% vs 0.5%, aOR 2.95, 95% CI 1.85 to 4.71, p<0.001), and acute renal failure (31.5% vs 23.1%, aOR 1.23, 95% CI 1.07 to 1.40, p=0.003). In conclusion, patients with pneumonia were associated with significantly higher rates of system-based complications and higher in-hospital mortality rates.

Clostridium difficile: Diagnosis and the Consequence of Over Diagnosis

Clostridium difficile infection (CDI) is a leading cause of healthcare-associated infections, accounting for significant disease burden and mortality. The clinical spectrum of C. difficile ranges from asymptomatic colonization to toxic megacolon and fulminant colitis. CDI is characterized by new onset of ≥ 3 unformed stools in 24 h and is confirmed by laboratory test for the presence of toxigenic C. difficile. Currently, laboratory tests to diagnose CDI include toxigenic culture, glutamate dehydrogenase (GDH), nucleic acid amplification test (NAAT), and toxins A/B enzyme immunoassay (EIA). The sensitivities of these tests are variable with toxin EIA ranging from 53 to 60% and with NAAT at about 95%. Overall, the specificity is > 90% for these methods. However, the positive predictive value (PPV) depends on the disease prevalence with lower CDI rates associated with lower PPVs.

Notably, the widespread use of the highly sensitive NAAT and its relatively lower clinical specificity have led to overdiagnosis of C. difficile by identifying carriers when NAAT is used as the sole diagnostic method. Overdiagnosis of C. difficile has resulted in unwarranted treatment, possibly attributing to resistance to metronidazole and vancomycin, increased risk for overgrowth of vancomycin-resistant enterococci strains in stool specimens, and increased hospitalization thereby impacting patient safety and healthcare costs.

Strategies to optimize the clinical sensitivity and specificity of current laboratory tests are critical to differentiate the clinical CDI from colonization. To achieve high diagnostic yield, if preagreed institutional criteria for stool submission are not used, a multistep approach to CDI diagnosis is recommended, such as either GDH or NAAT followed by toxins A/B EIA in conjunction with laboratory stewardship by evaluating C. difficile test orders for appropriateness and providing feedback. Furthermore, antimicrobial stewardship, along with provider education on appropriate testing for C. difficile, is vital to differentiate CDI from colonization.

Which Type of Empiric Antibiotic Therapy is Appropriate? A 20-Year Retrospective Study of Bloodstream Infections in Childhood Cancer

INTRODUCTION

Sufficient empirical antimicrobial therapy in febrile patients with cancer is challenging, owing to the limited arsenal of available antibiotics in an era of growing resistance. Because of the emergence of gram-negative bacteria resistant to ceftazidime and piperacillin, a combination antibiotic therapy was employed that uses meropenem combined with gentamicin and/or vancomycin if the patient further deteriorates.

METHODS

A retrospective cohort analysis was performed including all patients with catheter-associated bloodstream infections (BSIs) and treated for childhood cancer in a tertiary single centre between 1 January 2000 and 31 June 2018. We calculated the prevalence and the risk for BSIs and compared the in vitro susceptibility to various antimicrobial agents.

RESULTS

Of 653 patients with childhood cancer, 113 patients (17.3%) were identified with a total of 139 BSIs, most of them occurring in patients with leukaemia (n = 90, 64.7%) and were associated with gram-positive bacteria (60.5%). In our cohort, all BSIs with gram-negative bacteria exhibited in vitro susceptibility against meropenem alone without any signs of resistance development. The antibiotic coverage of our meropenem-based combination therapy was also highly effective for gram-positive and non-fermenting bacteria. Thus, BSI-related mortality in all 139 BSI episodes was 1.4%. Clostridium difficile infections (CDIs), as main adverse event of carbapenem usage, occurred in only 16 (2.5%) patients.

CONCLUSION

Our meropenem-based combination therapy showed sufficient empirical antibiotic coverage in the majority of BSIs (96.4%) and did not result in an increased rate of unwanted side effects or development of antibiotic resistance.

Antimicrobial prophylaxis in adult cardiac surgery in the United Kingdom and Republic of Ireland

BACKGROUND

Deep sternal wound infections are a financially costly complication of cardiac surgery with serious implications for patient morbidity and mortality. Prophylactic antimicrobials have been shown to reduce the incidence of infection significantly. In 2018, the European Association for CardioThoracic Surgery (EACTS) provided clear guidance advising that third-generation cephalosporins are the first-line prophylactic antimicrobial of choice for cardiac surgery via median sternotomy as a result of their broad spectrum of activity and association with reduced postoperative mortality. Despite this guidance, it was believed that UK practice differed from this as a consequence of national concerns surrounding cephalosporins use and Clostridioides difficile infection.

METHODS

A survey was developed and distributed to all UK and Republic of Ireland (ROI) cardiac surgery centres in January 2019 to quantify this variation.

RESULTS

Of the 38 centres, 34 responded. Variation existed between the antimicrobial agent used, as well as the dosage, frequency and duration of suggested regimens even among centres using the same antimicrobial agent. The most common antimicrobial prophylaxis prescribed was a combination of flucloxacillin and gentamicin (16, 47%). Followed by cefuroxime (6, 17.6%) and cefuroxime combined with a glycopeptide (4, 11.7%). In patients colonised with methicillin-resistant Staphylococcus aureus or those with penicillin allergy gentamicin combined with teicoplanin was most common (42% and 50%, respectively).

DISCUSSION

This variation in antimicrobial agents and regimens may well contribute to the varying incidence of surgical site infection seen across the UK and ROI.

Gut microbiome and Clostridioides difficile infection: a closer look at the microscopic interface

The pathogenesis of Clostridioides difficile infection (CDI) was recognized with its link to the use of antimicrobials. Antimicrobials significantly alter gut microbiota structure and composition, which led to the discovery of the association of this gut perturbation with the development of CDI. A number of factors implicated in its pathogenesis, such as advancing age, proton-pump inhibitors, and gastrointestinal diseases, are linked to gut microbiota perturbations. In an effort to better understand CDI, a multitude of studies have tried to ascertain protective and predictive microbial footprints linked with CDI. It has further been realized that CDI in itself can alter the gut microbiome. Its spore-forming capability poses as an impediment in the management of the infection and contributes to its recurrence. Antibiotic therapies used for its management have also been linked to gut microbiota changes, making its treatment a little more challenging. In an effort to exploit and utilize this association, gut microbial restoration therapies, particularly in the form of fecal microbial transplant, are increasingly being put to use and are proving to be beneficial. In this review, we summarize the association of the gut microbiome and microbial perturbation with initial and recurrent CDI.

Proteomic Adaptation of Clostridioides difficile to Treatment with the Antimicrobial Peptide Nisin

Clostridioides difficile is the leading cause of antibiotic-associated diarrhea but can also result in more serious, life-threatening conditions. The incidence of C. difficile infections in hospitals is increasing, both in frequency and severity, and antibiotic-resistant C. difficile strains are advancing. Against this background antimicrobial peptides (AMPs) are an interesting alternative to classic antibiotics. Information on the effects of AMPs on C. difficile will not only enhance the knowledge for possible biomedical application but may also provide insights into mechanisms of C. difficile to adapt or counteract AMPs. This study applies state-of-the-art mass spectrometry methods to quantitatively investigate the proteomic response of C. difficile 630∆erm to sublethal concentrations of the AMP nisin allowing to follow the cellular stress adaptation in a time-resolved manner. The results do not only point at a heavy reorganization of the cellular envelope but also resulted in pronounced changes in central cellular processes such as carbohydrate metabolism. Further, the number of flagella per cell was increased during the adaptation process. The potential involvement of flagella in nisin adaptation was supported by a more resistant phenotype exhibited by a non-motile but hyper-flagellated mutant.

High Prevalence of Multidrug-Resistant Clostridioides difficile Following Extensive Use of Antimicrobials in Hospitalized Patients in Kenya

Introduction

Clostridioides difficile is a neglected pathogen in many African countries as it is generally not regarded as one of the major contributors toward the diarrheal disease burden in the continent. However, several studies have suggested that C. difficile infection (CDI) may be underreported in many African settings. The aim of this study was to determine the prevalence of CDI in hospitalized patients, evaluate antimicrobial exposure, and detect toxin and antimicrobial resistance profiles of the isolated C. difficile strains.

Methods

In this cross-sectional study, 333 hospitalized patients with hospital-onset diarrhoea were selected. The stool samples were collected and cultured on cycloserine-cefoxitin egg yolk agar (CCEY). Isolates were presumptively identified by phenotypic characteristics and Gram stain and confirmed by singleplex real-time PCR (qPCR) assays detecting the species-specific tpi gene, toxin A (tcdA) gene, toxin B (tcdB) gene, and the binary toxin (cdtA/cdtB) genes. Confirmed C. difficile isolates were tested against a panel of eight antimicrobials (vancomycin, metronidazole, rifampicin, ciprofloxacin, tetracycline, clindamycin, erythromycin, and ceftriaxone) using E-test strips.

Results

C. difficile was detected in 57 (25%) of diarrheal patients over the age of two, 56 (98.2%) of whom received antimicrobials before the diarrheal episode. Amongst the 71 confirmed isolates, 69 (97.1%) harbored at least one toxin gene. More than half of the toxigenic isolates harbored a truncated tcdA gene. All isolates were sensitive to vancomycin, while three isolates (2.1%) were resistant to metronidazole (MIC >32 mg/L). High levels of resistance were observed to rifampicin (65/71, 91.5%), erythromycin (63/71, 88.7%), ciprofloxacin (59/71, 83.1%), clindamycin (57/71, 80.3%), and ceftriaxone (36/71, 50.7.8%). Among the resistant isolates, 61 (85.9%) were multidrug-resistant.

Conclusion

Multidrug-resistant C. difficile strains were a significant cause of healthcare facility-onset C. difficile infections in patients with prior antimicrobial exposure in this Kenyan hospital.

Clostridioides difficile Infection in a Rural New Zealand Secondary Care Centre: An Incidence Case-Control Study

BACKGROUND

Clostridioides difficile Infection (CDI) is a form of antibiotic associated infectious diarrhoea resulting in significant morbidity and mortality. Community acquired disease in low risk individuals is increasingly recognised. There are limited New Zealand data published.

AIM

To determine the incidence and location of onset of CDI cases in the Manawatu region, and further describe the demographics, risk factors and prevalent C. difficile ribotypes of the population.

METHODS

We performed an incidence case-control study of CDI in the Manawatu region between September 2018 and September 2019. Cases were matched to controls with a negative test for C. difficile. Demographic and comorbidity data, location of onset, drug exposure, disease recurrence and 30-day mortality were collected. Ribotype analysis was performed on C. difficile isolates.

RESULTS

32 specimens tested toxin positive over twelve months, yielding an incidence of 18.3 cases per 100,000 person-years. 25% of cases had community onset disease. Cases were more likely to have had amoxicillin/clavulanate or ceftriaxone prescribed. Elevated blood white cell count and lower HbA1c were significantly associated with CDI. The dominant ribotype was 014/020, 2 cases were RT 023.

CONCLUSION

Our data are similar to previous national data. RT 023 has not been previously reported in New Zealand and has been associated with severe colitis. We demonstrated a significant proportion of community acquired cases and the true incidence may be higher. Vigilance for community onset disease is required. This data may allow observation of temporal changes in incidence and infection patterns of CDI in New Zealand. This article is protected by copyright. All rights reserved.

Inappropriate empirical antibiotic therapy for bloodstream infections based on discordant in-vitro susceptibilities: a retrospective cohort analysis of prevalence, predictors, and mortality risk in US hospitals

BACKGROUND

The prevalence and effects of inappropriate empirical antibiotic therapy for bloodstream infections are unclear. We aimed to establish the population-level burden, predictors, and mortality risk of in-vitro susceptibility-discordant empirical antibiotic therapy among patients with bloodstream infections.

METHODS

Our retrospective cohort analysis of electronic health record data from 131 hospitals in the USA included patients with suspected-and subsequently confirmed-bloodstream infections who were treated empirically with systemic antibiotics between Jan 1, 2005, and Dec 31, 2014. We included all patients with monomicrobial bacteraemia caused by common bloodstream pathogens who received at least one systemic antibiotic either on the day blood cultures were drawn or the day after, and for whom susceptibility data were available. We calculated the prevalence of discordant empirical antibiotic therapy-which was defined as receiving antibiotics on the day blood culture samples were drawn to which the cultured isolate was not susceptible in vitro-overall and by hospital type by using regression tree analysis. We used generalised estimating equations to identify predictors of receiving discordant empirical antibiotic therapy, and used logistic regression to calculate adjusted odds ratios for the relationship between in-hospital mortality and discordant empirical antibiotic therapy.

FINDINGS

21 608 patients with bloodstream infections received empirical antibiotic therapy on the day of first blood culture collection. Of these patients, 4165 (19%) received discordant empirical antibiotic therapy. Discordant empirical antibiotic therapy was independently associated with increased risk of mortality (adjusted odds ratio 1·46 [95% CI, 1·28-1·66]; p<0·0001), a relationship that was unaffected by the presence or absence of resistance or sepsis or septic shock. Infection with antibiotic-resistant species strongly predicted receiving discordant empirical therapy (adjusted odds ratio 9·09 [95% CI 7·68-10·76]; p<0·0001). Most incidences of discordant empirical antibiotic therapy and associated deaths occurred among patients with bloodstream infections caused by Staphylococcus aureus or Enterobacterales.

INTERPRETATION

Approximately one in five patients with bloodstream infections in US hospitals received discordant empirical antibiotic therapy, receipt of which was closely associated with infection with antibiotic-resistant pathogens. Receiving discordant empirical antibiotic therapy was associated with increased odds of mortality overall, even in patients without sepsis. Early identification of bloodstream pathogens and resistance will probably improve population-level outcomes.

FUNDING

US National Institutes of Health, US Centers for Disease Control and Prevention, and US Agency for Healthcare Research and Quality.

Antibiotics in treatment of peritonsillar infection: clindamycin versus penicillin

OBJECTIVE

This study aimed to compare antibiotic treatment with clindamycin versus penicillin V or G in terms of time to recovery and recurrence in patients with peritonsillar infection, including both peritonsillar cellulitis and peritonsillar abscess.

METHOD

This retrospective cohort study examined the records of 296 patients diagnosed with peritonsillar infection. Based on the ENT doctor's choice of antibiotics, patients were divided into clindamycin and penicillin groups.

RESULTS

Mean number of days in follow up was 3.5 days in the clindamycin group and 3.4 days in the penicillin group. The recurrence rate within 2 months was 7 per cent in the clindamycin group and 4 per cent in the penicillin group.

CONCLUSION

This study found no significant differences in either recovery or recurrence between the groups. This supports the use of penicillin as a first-line treatment, considering the greater frequency of adverse effects of clindamycin shown in previous studies, as well as its profound collateral damage on the intestinal microbiota, resulting in antibiotic resistance.

Omadacycline vs moxifloxacin in adults with community-acquired bacterial pneumonia

OBJECTIVE

Community-acquired bacterial pneumonia (CABP) is a major clinical burden worldwide. In the phase III OPTIC study (NCT02531438) in CABP, omadacycline was found to be non-inferior to moxifloxacin for investigator-assessed clinical response (IACR) at post-treatment evaluation (PTE, 5-10 days after last dose). This article reports the efficacy findings, as specified in the European Medicines Agency (EMA) guidance.

METHODS

Patients were randomized 1:1 to omadacycline 100 mg intravenously (every 12 h for two doses, then every 24 h) with optional transition to 300 mg orally after 3 days, or moxifloxacin 400 mg intravenously (every 24 h) with optional transition to 400 mg orally after 3 days. The total treatment duration was 7-14 days. The primary endpoint for EMA efficacy analysis was IACR at PTE in patients with Pneumonia Patient Outcomes Research Team (PORT) risk class III and IV.

RESULTS

In total, 660 patients were randomized as PORT risk class III and IV. Omadacycline was non-inferior to moxifloxacin at PTE. The clinical success rates were 88.4% and 85.2%, respectively [intent-to-treat population; difference 3.3; 97.5% confidence interval (CI) -2.7 to 9.3], and 92.5% and 90.5%, respectively (clinically evaluable population; difference 2.0; 97.5% CI 3.2-7.4). Clinical success rates with omadacycline and moxifloxacin were similar against identified pathogens and across key subgroups.

CONCLUSIONS

Omadacycline was non-inferior to moxifloxacin for IACR at PTE, with high clinical success across pathogen types and patient subgroups.

Uncovering the Harms of Treating Clostridioides difficile Colonization

Patients with toxin-negative Clostridioides difficile-positive diarrhea are often treated with oral vancomycin with the assumption that treatment is more beneficial than harmful. However, this hypothesis has never been formally tested, and recent studies suggest that most such patients recover quickly without treatment and can be colonized rather than infected.

Patients with toxin-negative Clostridioides difficile-positive diarrhea are often treated with oral vancomycin with the assumption that treatment is more beneficial than harmful. However, this hypothesis has never been formally tested, and recent studies suggest that most such patients recover quickly without treatment and can be colonized rather than infected. Fishbein et al. conducted a prospective, placebo-controlled randomized trial to systematically evaluate the effects, risks, and benefits of oral vancomycin in these patients (S. R. S. Fishbein, T. Hink, K. A. Reske, C. Cass, et al., mSphere 6:e00936-20, 2020, https://doi.org/10.1128/mSphere.00936-20). Although small, the results are intriguing and suggest the adverse antibiotic-induced effects of vancomycin outweigh the clinical benefit when colonization is more likely than disease.

Is there a role of penicillin allergy in developing Clostridioides difficile infection?

PURPOSE OF REVIEW

To explore the evidence for an association between penicillin allergy, antibiotic prescribing and Clostridioides difficile (CDI) infection.

RECENT FINDINGS

Several studies have highlighted the differences in antibiotic prescribing in penicillin allergic patients and the impact on rates of C. difficile infection.

SUMMARY

Penicillin allergy leads to higher incidences of prescriptions for antibiotics that are known to predispose to CDI. In turn CDI is more common in patients with penicillin allergy. Penicillin allergy is often erroneously ascribed to patients and should be challenged.

Economic burden and cost-effectiveness of therapies for Clostridiodes difficile infection: a narrative review

Clostridioides difficile is the most common cause of healthcare-associated diarrhea. Disease complications as well as recurrent infections contribute significantly to morbidity and mortality. Over the past decades, there has been a rapid increase in the incidence of C. difficile infection (CDI), with a rise in the number of community-acquired cases. CDI has a profound economic impact on both the healthcare system and patients, secondary to recurrences, hospitalization, prolonged length of stay, cost of treatment, and indirect societal costs. With emergence of newer treatment options, the standard of care is shifting from metronidazole and vancomycin towards fidaxomicin and fecal microbiota transplantation (FMT), which despite being more expensive, are more efficacious in preventing recurrences and hence overall are more beneficial forms of therapy per cost-effectiveness analyses. Data regarding preferred route of FMT, timing of FMT, and non-conventional therapies such as bezlotoxumab is scant. There is a need for further studies to elucidate the true attributable costs of CDI as well as continued cost-effectiveness research to reduce the economic burden associated with the disease and improve clinical practice.

Microbiota-mediated protection against antibiotic-resistant pathogens

Colonization by the microbiota provides one of our most effective barriers against infection by pathogenic microbes. The microbiota protects against infection by priming immune defenses, by metabolic exclusion of pathogens from their preferred niches, and through direct antimicrobial antagonism. Disruption of the microbiota, especially by antibiotics, is a major risk factor for bacterial pathogen colonization. Restoration of the microbiota through microbiota transplantation has been shown to be an effective way to reduce pathogen burden in the intestine but comes with a number of drawbacks, including the possibility of transferring other pathogens into the host, lack of standardization, and potential disruption to host metabolism. More refined methods to exploit the power of the microbiota would allow us to utilize its protective power without the drawbacks of fecal microbiota transplantation. To achieve this requires detailed understanding of which members of the microbiota protect against specific pathogens and the mechanistic basis for their effects. In this review, we will discuss the clinical and experimental evidence that has begun to reveal which members of the microbiota protect against some of the most troublesome antibiotic-resistant pathogens: Klebsiella pneumoniae, vancomycin-resistant enterococci, and Clostridioides difficile.

Systematic Literature Review on Burden of Clostridioides difficile Infection in India

BACKGROUND

Owing to limited diagnostic facilities and surveillance protocols, there is a paucity on the prevalence data of Clostridioides difficile infections (CDIs) in developing countries such as India.

OBJECTIVE

The aims of these studies are (1) to determine the prevalence of CDI in India, (2) to understand the risk factors of CDI, and (3) to determine the impact of different diagnostic methods on reported CDI rates.

METHOD

A systematic literature search was conducted using PubMed and Google Scholar database to identify Indian studies reporting the prevalence of CDI. A total of 31 studies, published between 1990 and 2020 were included in the final analysis. A chi-square test was used to determine statistically significant association between prevalence rates, accuracy of different diagnosis methods, and antibiotic usage rates of CDI.

RESULTS

The prevalence of CDI was in the range of 3.4% to 18%, and the difference between regional prevalence of CDI was statistically significant (P < .001). The use of antibiotics, hospital stay, comorbidities, recent surgery, and the use of proton-pump inhibitors was considered as risk factors for the development of CDI. Compared to other regions, the rate of antibiotic usage was significantly higher in North India (P < .001). Among different diagnostic methods, C. difficile detection was significantly higher with enzyme-linked immunosorbent assay (18.02%) versus other multiple testing methods used (P < .001).

CONCLUSION

There is a significant burden of CDI across the country. Further surveillance studies are required to monitor changes in prevalence of CDI, risk factors, and accuracy of diagnosis methods for a better understanding of the disease burden in India.

Critical Care Management of the Patient with Clostridioides difficile

OBJECTIVES

To review published clinical evidence on management of Clostridioides difficile infection in critically ill patients.

DATA SOURCES

We obtained relevant studies from a PubMed literature review and bibliographies of reviewed articles.

STUDY SELECTION

We selected English-language studies addressing aspects of C. difficile infection relevant to critical care clinicians including epidemiology, risk factors, diagnosis, treatment, and prevention, with a focus on high-quality clinical evidence.

DATA EXTRACTION

We reviewed potentially relevant studies and abstracted information on study design, methods, patient selection, and results of relevant studies. This is a synthetic (i.e., not systematic) review.

DATA SYNTHESIS

C. difficile infection is the most common healthcare-associated infection in the United States. Antibiotics are the most significant C. difficile infection risk factor, and among antibiotics, cephalosporins, clindamycin, carbapenems, fluoroquinolones, and piperacillin-tazobactam confer the highest risk. Age, diabetes mellitus, inflammatory bowel disease, and end-stage renal disease are risk factors for C. difficile infection development and mortality. C. difficile infection diagnosis is based on testing appropriately selected patients with diarrhea or on clinical suspicion for patients with ileus. Patients with fulminant disease (C. difficile infection with hypotension, shock, ileus, or megacolon) should be treated with oral vancomycin and IV metronidazole, as well as rectal vancomycin in case of ileus. Patients who do not respond to initial therapy should be considered for fecal microbiota transplant or surgery. Proper infection prevention practices decrease C. difficile infection risk.

CONCLUSIONS

Strong clinical evidence supports limiting antibiotics when possible to decrease C. difficile infection risk. For patients with fulminant C. difficile infection, oral vancomycin reduces mortality, and adjunctive therapies (including IV metronidazole) and interventions (including fecal microbiota transplant) may benefit select patients. Several important questions remain regarding fulminant C. difficile infection management, including which patients benefit from fecal microbiota transplant or surgery.

Faecal transplantation and Clostridioides difficile infection

Faecal microbiota transplantation (FMT), known equally well as faecal transplantation or faecal bacteriotherapy, is the process of implanting the faecal suspension containing balanced microbiota from a healthy donor to the colon of a recipient patient. Excessive growth of Clostridioides difficile (C difficile) in the intestinal microbiota resulting from antibiotic consumption is currently a rising threat to public health. FMT is one of the most important, newer approaches to treating C difficile infections. Since C difficile is regarded as an opportunistic bacterium triggering disease in conditions of disturbed homeostasis of the intestinal microbiota, restoration of healthy intestinal microflora facilitates suppression of toxic strain of C difficile by anaerobic bacteria of normal intestinal microflora with concomitant cure. Nurses have important role in caring for patients after faecal transplantation.

To give or not to give antibiotics is not the only question

In a 1945 Nobel Lecture, Sir Alexander Fleming warned against the overuse of antibiotics, particularly in response to public pressure. In the subsequent decades, evidence has shown that bacteria can become resistant to almost any available molecule. One key question is how the emergence and dissemination of resistant bacteria or resistance genes can be delayed. Although some clinicians remain sceptical, in this Personal View, we argue that the prescription of fewer antibiotics and shorter treatment duration is just as effective as longer regimens that remain the current guideline. Additionally, we discuss the fact that shorter antibiotic treatments exert less selective pressure on microorganisms, preventing the development of resistance. By contrast, longer treatments associated with a strong selective pressure favour the emergence of resistant clones within commensal organisms. We also emphasise that more studies are needed to identify the optimal duration of antibiotic therapy for common infections, which is important for making changes to the current guidelines, and to identify clinical biomarkers to guide antibiotic treatment in both hospital and ambulatory settings.

Characterization of Clostridioides difficile Strains, the Disease Severity, and the Microbial Changes They Induce

BACKGROUND

Clostridioides difficile infection (CDI) is a major nosocomial disease. The characteristics of different strains, the disease severity they cause, their susceptibility to antibiotics, and the changes they inflict on gut microbiome, have not been comprehensively studied in Israel.

METHODS

A severity score was calculated for 70 patients. Stool samples were tested for toxins presence using a special kit. Bacteria were isolated, identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) and antibiotic susceptibility tests were performed for several antibiotics. Strains were classified by Multi-locus sequence typing (MLST), and changes in gut microbiome were tested.

RESULTS

ST04 (22.5%) and ST37 (12.7%) were the most frequent strains. Clade (phylogenetic lineage) 1 was the most (81.4%) prevalent. We found significant associations between ST and age (p = 0.024) and between ST and moxifloxacin susceptibility (p = 0.001). At the clade level, we found significant associations with binary toxin gene occurrence (p = 0.002), and with susceptibility to both metronidazole and vancomycin (p = 0.024, 0.035, respectively). Differences in intestine microbiome were affected by age, clades' distribution and STs.

CONCLUSIONS

By defining the characteristics of the different strains and clades, clinicians can choose medical interventions based on the predicted response or disease severity associated with each strain, enabling new advances in the field of personalized medicine.

Mechanisms of Colonization Resistance Against Clostridioides difficile

Clostridioides difficile is an urgent antimicrobial-resistant bacterium, causing mild to moderate and sometimes life-threatening disease. Commensal gut microbes are critical for providing colonization resistance against C difficile and can be leveraged as non-antibiotic alternative therapeutics for the prevention and treatment of C difficile infection.

Clinical consequences of contaminated blood cultures in adult hospitalized patients at an institution utilizing a rapid blood-culture identification system

OBJECTIVE

To assess the clinical impact of contaminated blood cultures in hospitalized patients during a period when rapid diagnostic testing using a FilmArray Blood Culture Identification (BCID) panel was in use.

DESIGN

Retrospective cohort study.

SETTING

Single academic medical center.

PARTICIPANTS

Patients who had blood culture(s) performed during an admission between June 2014 and December 2016.

METHODS

Length of hospital stay and days of antibiotic therapy were assessed in relation to blood-culture contamination using generalized linear models with univariable and multivariable analyses.

RESULTS

Among 11,474 patients who had blood cultures performed, the adjusted mean length of hospital stay for patients with contaminated blood-culture episodes (N = 464) was 12.3 days (95% confidence interval [CI], 11.4-13.2) compared to 11.5 days (95% CI, 11.0-11.9) for patients (N = 11,010) with negative blood-culture episodes (P = .032). The adjusted mean durations of antibiotic therapy for patients with contaminated and negative blood-culture episodes were 6.0 days (95% CI, 5.3-6.7) and 5.2 days (95% CI, 4.9-5.4), respectively (P = .011).

CONCLUSIONS

Despite the use of molecular-based, rapid blood-culture identification, contamination of blood cultures continues to result in prolonged hospital stay and unnecessary antibiotic therapy in hospitalized patients.

Clostridioides difficile ribotypes 001 and 126 were predominant in Tehran healthcare settings from 2004 to 2018: a 14-year-long cross-sectional study

Clostridioides difficile infection (CDI) remains a major healthcare problem worldwide, however, little is known about CDI epidemiology in Iran. Between December 2004 and November 2018, 3649 stool samples were collected from patients in 69 hospitals and medical centres in Tehran and were cultured for the presence of C. difficile; isolates were characterized by PCR ribotyping and toxin genes detection. A total of 582 C. difficile isolates were obtained and the overall CDI prevalence was 15.9%; 290 (49.8%) cases were healthcare-associated (HA) and 292 (50.2%) cases were community-associated (CA). Of these, DNA of 513 isolates submitted for ribotyping. The ribotype and/or WEBRIBO type could be assessed in 366 (62.9%) isolates. The most frequent RTs were 001 (n = 75, 12.9%), 126 (n = 65, 11.2%) and 084 (n = 19, 3.3%); the toxin gene profile tcdA + B + /cdtA + B + (n = 112, 19.2%) was the most common. Fifteen C. difficile isolates (2.6%) did not carry any toxin genes. There was no difference between frequently found RTs in HA-CDI and CA-CDI, except for RT 029 which was more likely to be associated with healthcare origin (12/15, p-value = 0.02). No isolate of RTs 027 or 078 was identified. Importantly, RTs 031, 038, 039, 084, 085 reported previously as RTs with an absence of toxin genes, revealed the presence of toxin genes in our study. Using Simpson's reciprocal index of diversity, we found that RT diversity decreased as the prevalence of the RT 084 increased (R = -0.78, p-value = 0.041). Different patterns in CDI epidemiology underscore the importance of local surveillance and infection control measures in Tehran healthcare settings.

Association Between Antibiotic Use and Hospital-onset Clostridioides difficile Infection in US Acute Care Hospitals, 2006-2012: An Ecologic Analysis

BACKGROUND

Unnecessary antibiotic use (AU) contributes to increased rates of Clostridioides difficile infection (CDI). The impact of antibiotic restriction on hospital-onset CDI (HO-CDI) has not been assessed in a large group of US acute care hospitals (ACHs).

METHODS

We examined cross-sectional and temporal associations between rates of hospital-level AU and HO-CDI using data from 549 ACHs. HO-CDI was defined as a discharge with a secondary International Classification of Diseases, Ninth Revision, Clinical Modification code for CDI (008.45), and treatment with metronidazole or oral vancomycin > 3 days after admission. Analyses were performed using multivariable generalized estimating equation models adjusting for patient and hospital characteristics.

RESULTS

During 2006-2012, the unadjusted annual rates of HO-CDI and total AU were 7.3 per 10 000 patient-days (PD) (95% confidence interval [CI], 7.1-7.5) and 811 days of therapy (DOT)/1000 PD (95% CI, 803-820), respectively. In the cross-sectional analysis, for every 50 DOT/1000 PD increase in total AU, there was a 4.4% increase in HO-CDI. For every 10 DOT/1000 PD increase in use of third- and fourth-generation cephalosporins or carbapenems, there was a 2.1% and 2.9% increase in HO-CDI, respectively. In the time-series analysis, the 6 ACHs with a ≥30% decrease in total AU had a 33% decrease in HO-CDI (rate ratio, 0.67 [95% CI, .47-.96]); ACHs with a ≥20% decrease in fluoroquinolone or third- and fourth-generation cephalosporin use had a corresponding decrease in HO-CDI of 8% and 13%, respectively.

CONCLUSIONS

At an ecologic level, reductions in total AU, use of fluoroquinolones, and use of third- and fourth-generation cephalosporins were each associated with decreased HO-CDI rates.

Rethinking Carbapenems: A Pharmacokinetic Approach for Antimicrobial Selection in Infected Necrotizing Pancreatitis

OBJECTIVE

To provide an overview of pathophysiological changes to the pancreas during infected necrotizing pancreatitis (INP), optimal drug properties needed to penetrate the pancreas, human and animal studies supporting the use of antimicrobials, and carbapenem-sparing strategies in INP.

DATA SOURCES

A literature analysis of PubMed/MEDLINE was performed (from 1960 to September 2020) using the following key terms: infected necrotizing pancreatitis, necrotizing acute pancreatitis, and infected pancreatitis antimicrobial concentration. Individual antimicrobials were investigated with these search terms.

STUDY SELECTION AND DATA EXTRACTION

All relevant studies describing the management of INP, and human and animal pharmacokinetic (PK) data supporting antimicrobial use in the pancreas were reviewed for possible inclusion regardless of sample size or study design.

DATA SYNTHESIS

Piperacillin/tazobactam and cefepime achieve adequate pancreatic tissue concentrations in INP studies. A majority of the literature supporting carbapenem use in INP involves imipenem, and meropenem Monte Carlo simulations suggest that standard dosing regimens of meropenem may not achieve PK targets to eradicate Pseudomonas aeruginosa.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Carbapenems are often utilized for INP treatment based on guideline recommendations. This review discusses PK data, the history of carbapenem use in INP, and the pathophysiology of pancreatitis to suggest carbapenem-sparing strategies and provides stewardship tactics such as when to start antimicrobials, which empirical antimicrobial to use, and when to discontinue antimicrobials in the INP setting.

CONCLUSIONS

Noncarbapenem antipseudomonals, such as piperacillin/tazobactam and cefepime, are appropriate carbapenem-sparing options in INP, based on PK data, spectrum of activity, and risk of collateral damage.

Comparing intervention strategies for reducing Clostridioides difficile transmission in acute healthcare settings: an agent-based modeling study

BACKGROUND

Clostridioides difficile infection (CDI) is one of the most common healthcare infections. Common strategies aiming at controlling CDI include antibiotic stewardship, environmental decontamination, and improved hand hygiene and contact precautions. Mathematical models provide a framework to evaluate control strategies. Our objective is to evaluate the effectiveness of control strategies in decreasing C. difficile colonization and infection using an agent-based model in an acute healthcare setting.

METHODS

We developed an agent-based model that simulates the transmission of C. difficile in medical wards. This model explicitly incorporates healthcare workers (HCWs) as vectors of transmission, tracks individual patient antibiotic histories, incorporates varying risk levels of antibiotics with respect to CDI susceptibility, and tracks contamination levels of ward rooms by C. difficile. Interventions include two forms of antimicrobial stewardship, increased environmental decontamination through room cleaning, improved HCW compliance, and a preliminary assessment of vaccination.

RESULTS

Increased HCW compliance with CDI patients was ranked as the most effective intervention in decreasing colonizations, with reductions up to 56%. Antibiotic stewardship practices were highly ranked after contact precaution compliance. Vaccination and reduction of high-risk antibiotics were the most effective intervention in decreasing CDI. Vaccination reduced CDI cases to up to 90%, and the reduction of high-risk antibiotics decreased CDI cases up to 23%.

CONCLUSIONS

Overall, interventions that decrease patient susceptibility to colonization by C. difficile, such as antibiotic stewardship, were the most effective interventions in reducing both colonizations and CDI cases.

Healthcare associated Clostridioides difficile infection in adult surgical and medical patients hospitalized in tertiary hospital in Belgrade, Serbia: a seven years prospective cohort study

Introduction: Clostridioides difficile (C. difficile) infection (CDI) is one of the most common healthcare-associated (HA) infections in contemporary medicine. The risk factors (RFs) for HA CDI in medical and surgical patients are poorly investigated in countries with a limited resource healthcare system. Therefore, the aim of the study was to investigate differences in patients' characteristics, factors related to healthcare and outcomes associated with HA CDI in surgical and medical patients in tertiary healthcare centre in Serbia.Materials and Methods: A prospective cohort study was conducted including adult patients diagnosed with initial episode of HA CDI, first recurrence of disease, readmission to hospital, while deaths within 30 days of CDI diagnosis and in-hospital mortality were also recorded. Patients hospitalized for any non-surgical illness, who developed initial HA CDI were assigned to medical group, whereas those who developed initial HA CDI after surgical procedures were in surgical group. The data on patients' characteristics and factors related to healthcare were collected, too.Results: During 7-year period, from 553 patients undergoing in-hospital treatment and diagnosed with CDI, 268 (48.5%) and 285 (51.5%) were surgical and medical patients, respectively. Age ≥ 65 years, use of proton pump inhibitors, chemotherapy and fluoroquinolones were positively associated with being in medical group, whereas admission to intensive care unit and use of second- and third-generation cephalosporins were positively associated with being in surgical group.Conclusions: Based on obtained results, including significant differences in 30-day mortality and in-hospital mortality, it can be concluded that medical patient were more endangered with HA CDI than surgical ones.

Community-level consumption of antibiotics according to the AWaRe (Access, Watch, Reserve) classification in rural Vietnam

Objectives

To review community-level consumption of antibiotics in rural Vietnam, according to the WHO Access, Watch, Reserve (AWaRe) classification of 2019, and identify factors associated with the choice of these antibiotics.

Methods

In this cross-sectional study, data on antibiotic purchases were collected through a customer exit survey of 20 community antibiotic suppliers in Ba Vi District, Hanoi, between September 2017 and July 2018. Antibiotic consumption was estimated through the number of antibiotic encounters, the number of DDDs supplied and the number of treatment days (DOTs) with antibiotics, and analysed according to the AWaRe classification. The factors associated with watch-group antibiotic supply were identified through multivariable logistic regression analysis.

Results

In total, there were 1342 antibiotic encounters, with access-group antibiotics supplied in 792 encounters (59.0%), watch-group antibiotics supplied in 527 encounters (39.3%) and not-recommended antibiotics supplied in 23 encounters (1.7%). No reserve-group antibiotics were supplied. In children, the consumption of watch-group antibiotics dominated in all three measures (54.8% of encounters, 53.0% of DOTs and 53.6% of DDDs). Factors associated with a higher likelihood of watch-group antibiotic supply were: private pharmacy (OR, 4.23; 95% CI, 2.8–6.38; P < 0.001), non-prescription antibiotic sale (OR, 2.62; 95% CI, 1.78–3.87; P < 0.001) and children (OR, 2.56; 95% CI, 1.84–3.55; P < 0.001).

Conclusions

High consumption of watch-group antibiotics was observed, especially for use in children. The frequent supply of watch-group antibiotics at private pharmacies reconfirms the need for implementing pharmacy-targeted interventions in Vietnam.

A Baker's Dozen of Top Antimicrobial Stewardship Intervention Publications in 2019

Staying current on literature related to antimicrobial stewardship can be challenging given the ever-increasing number of published articles. The Southeastern Research Group Endeavor (SERGE-45) identified antimicrobial stewardship–related peer-reviewed literature that detailed an actionable intervention for 2019. The top 13 publications were selected using a modified Delphi technique. These manuscripts were reviewed to highlight the actionable intervention used by antimicrobial stewardship programs to provide key stewardship literature for teaching and training and to identify potential intervention opportunities within one’s institution.

Severe Clostridium difficile colitis as potential late complication associated with COVID-19

Spain has been one of the most affected countries by the COVID-19 outbreak. After the high impact of the pandemic, a wide clinical spectrum of late complications associated with COVID-19 are being observed. We report a case of a severe Clostridium difficile colitis in a post-treatment and recovered COVID-19 patient. A 64-year-woman with a one-month hospital admission for severe bilateral pneumonia associated with COVID-19 and 10 days after discharge presented with diarrhoea and abdominal pain. Severe C. difficile-associated colitis is diagnosed according to clinical features and CT findings. An urgent pancolectomy was performed due to her bad response to conservative treatment. Later evolution slowly improved to recovery. C. difficile-associated colitis is one of the most common hospital-acquired infections. Significant patient-related risk factors for C. difficile infection are antibiotic exposure, older age, and hospitalisation. Initial therapeutic recommendations in our country included administration broad-spectrum antibiotics to all patients with bilateral pneumonia associated with SARS-CoV-2. These antibiotics are strongly associated with C. difficile infection. Our patient developed a serious complication of C. difficile due to the use of broad-spectrum antibiotics. The appearance of late digestive symptoms in patients diagnosed and treated for COVID-19 should alert clinicians to the possibility of C. difficile infection. The updated criteria for severe colitis and severe C. difficile infection should be considered to ensure an early effective treatment for the complication.

Healthcare facility-onset, healthcare facility-associated Clostridioides difficile infection in Veterans with spinal cord injury and disorder

Objective: To describe the burden and risk of healthcare facility-onset, healthcare facility-associated (HO-HCFA) Clostridioides difficile infection (CDI) in Veterans with spinal cord injury and disorder (SCI/D). Design: Retrospective, longitudinal cohort study from October 1, 2001-September 30, 2010. Setting: Ninety-four acute care Veterans Affairs facilities. Participants: Patients with SCI/D. Outcomes: Incidence rate of HO-HCFA CDI. Methods: Rates of CDI were determined, and crude unadjusted incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were calculated. Multivariable Poisson random-effects regression analyses were used to assess factors independently associated with the rate of CDI. Results: 1,409 cases of HO-HCFA CDI were identified. CDI rates in 2002 were 13.9/10,000 person-days and decreased to 5.5/10,000 person-days by 2010. Multivariable regression analyses found that antibiotic (IRR = 18.79, 95% CI 14.09-25.07) and proton-pump inhibitor (PPI) or H2 blocker use (IRR = 7.71, 95% CI 5.47-10.86) were both independently associated with HO-HCFA CDI. Exposure to both medications demonstrated a synergistic risk (IRR = 37.55, 95% CI 28.39-49.67). Older age, Northeast region, and invasive respiratory procedure in the prior 30 days were also independent risk factors, while longer SCI duration and care at a SCI center were protective. Conclusion: Although decreasing, CDI rates in patients with SCI/D remain high. Targeted antimicrobial stewardship and pharmacy interventions that reduce antibiotic and PPI/H2 blocker use could have profound benefits in decreasing HO-HCFA CDI in this high-risk population.

Ribaxamase, an Orally Administered β-Lactamase, Diminishes Changes to Acquired Antimicrobial Resistance of the Gut Resistome in Patients Treated with Ceftriaxone

Introduction

Intravenous (IV) β-lactam antibiotics, excreted through bile into the gastrointestinal (GI) tract, may disrupt the gut microbiome by eliminating the colonization resistance from beneficial bacteria. This increases the risk for Clostridium difficile infection (CDI) and can promote antimicrobial resistance by selecting resistant organisms and eliminating competition by non-resistant organisms. Ribaxamase is an orally administered β-lactamase for use with IV β-lactam antibiotics (penicillins and cephalosporins) and is intended to degrade excess antibiotics in the upper GI before they can disrupt the gut microbiome and alter the resistome.

Methods

Longitudinal fecal samples (349) were collected from patients who participated in a previous Phase 2b clinical study with ribaxamase for prevention of CDI. In that previous study, patients were treated with ceftriaxone for a lower respiratory tract infection and received concurrent ribaxamase or placebo. Extracted fecal DNA from the samples was subjected to whole-genome shotgun sequencing and analyzed for the presence of antimicrobial resistance (AMR) genes by alignment of sequences against the Comprehensive Antibiotic Resistance Database. A qPCR assay was also used to confirm some of the results.

Results

Database alignment identified ~1300 acquired AMR genes and gene variants, including those encoding β-lactamases and vancomycin resistance which were significantly increased in placebo vs ribaxamase-treated patients following antibiotic exposure. qPCR corroborated the presence of these genes and supported both new acquisition and expansion of existing gene pools based on no detectable copy number or a low copy number in pre-antibiotic samples which increased post-antibiotics. Additional statistical analyses demonstrated significant correlations between changes in the gut resistome and clinical study parameters including study drug assignment and β-lactamase and vancomycin resistance gene frequency.

Discussion

These findings demonstrated that ribaxamase reduced changes to the gut resistome subsequent to ceftriaxone administration and may help limit the emergence of AMR.

Role of Early De-escalation of Antimicrobial Therapy on Risk of Clostridioides difficile Infection Following Enterobacteriaceae Bloodstream Infections

BACKGROUND

There is a paucity of data on the effect of early de-escalation of antimicrobial therapy on rates of Clostridioides difficile infection (CDI). This retrospective cohort study evaluated impact of de-escalation from antipseudomonal β-lactam (APBL) therapy within 48 hours of Enterobacteriaceae bloodstream infections (BSIs) on 90-day risk of CDI.

METHODS

Adult patients hospitalized for >48 hours for treatment of Enterobacteriaceae BSI at Palmetto Health hospitals in Columbia, South Carolina, from 1 January 2011 through 30 June 2015 were identified. Multivariable Cox proportional hazards regression was used to examine time to CDI in patients who received >48 hours or ≤48 hours of APBL for empirical therapy of Enterobacteriaceae BSI after adjustment for the propensity to receive >48 hours of APBL.

RESULTS

Among 808 patients with Enterobacteriaceae BSI, 414 and 394 received >48 and ≤48 hours of APBL, respectively. Incidence of CDI was higher in patients who received >48 hours than those who received ≤48 hours of APBL (7.0% vs 1.8%; log-rank P = .002). After adjustment for propensity to receive >48 hours of APBL and other variables in the multivariable model, receipt of >48 hours of APBL (hazard ratio [HR], 3.56 [95% confidence interval {CI}, 1.48-9.92]; P = .004) and end-stage renal disease (HR, 4.27 [95% CI, 1.89-9.11]; P = .001) were independently associated with higher risk of CDI.

CONCLUSIONS

The empirical use of APBL for >48 hours was an independent risk factor for CDI. Early de-escalation of APBL using clinical risk assessment tools or rapid diagnostic testing may reduce the incidence of CDI in hospitalized adults with Enterobacteriaceae BSIs.

An Integrated Safety Summary of Omadacycline, a Novel Aminomethylcycline Antibiotic

Omadacycline is a semisynthetic tetracycline antibiotic. Phase III clinical trial results have shown that omadacycline has an acceptable safety profile in the treatment of acute bacterial skin and skin structure infections and community-acquired bacterial pneumonia. Similar to most tetracyclines, transient nausea and vomiting and low-magnitude increases in liver aminotransferases were the most frequent treatment-emergent adverse events in phase III studies but were not treatment limiting. Package insert warnings and precautions for omadacycline include tooth discoloration; enamel hypoplasia; inhibition of bone growth following use in late pregnancy, infancy, or childhood up to 8 years of age; an imbalance in mortality (2%, compared with 1% in moxifloxacin-treated patients) was observed in the phase III study in patients with community-acquired bacterial pneumonia. Omadacycline has no effect on the QT interval, and its affinity for muscarinic M₂ receptors resulted in transient heart rate increases following dosing.

Identification of Simplified Microbial Communities That Inhibit Clostridioides difficile Infection through Dilution/Extinction

The gastrointestinal microbiome plays an important role in limiting susceptibility to infection with Clostridioides difficile To better understand the ecology of bacteria important for C. difficile colonization resistance, we developed an experimental platform to simplify complex communities of fecal bacteria through dilution and rapidly screen for their ability to resist C. difficile colonization after challenge, as measured by >100-fold reduction in levels of C. difficile in challenged communities. We screened 76 simplified communities diluted from cultures of six fecal donors and identified 24 simplified communities that inhibited C. difficile colonization in vitro Sequencing revealed that simplified communities were composed of 19 to 67 operational taxonomic units (OTUs) and could be partitioned into four distinct community types. One simplified community could be further simplified from 56 to 28 OTUs through dilution and retain the ability to inhibit C. difficile We tested the efficacy of seven simplified communities in a humanized microbiota mouse model. We found that four communities were able to significantly reduce the severity of the initial C. difficile infection and limit susceptibility to disease relapse. Analysis of fecal microbiomes from treated mice demonstrated that simplified communities accelerated recovery of indigenous bacteria and led to stable engraftment of 19 to 22 OTUs from simplified communities. Overall, the insights gained through the identification and characterization of these simplified communities increase our understanding of the microbial dynamics of C. difficile infection and recovery.IMPORTANCEClostridioides difficile is the leading cause of antibiotic-associated diarrhea and a significant health care burden. Fecal microbiota transplantation is highly effective at treating recurrent C. difficile disease; however, uncertainties about the undefined composition of fecal material and potential long-term unintended health consequences remain. These concerns have motivated studies to identify new communities of microbes with a simpler composition that will be effective at treating disease. This work describes a platform for rapidly identifying and screening new simplified communities for efficacy in treating C. difficile infection. Four new simplified communities of microbes with potential for development of new therapies to treat C. difficile disease are identified. While this platform was developed and validated to model infection with C. difficile, the underlying principles described in the paper could be easily modified to develop therapeutics to treat other gastrointestinal diseases.

Biogeography of microbial bile acid transformations along the murine gut

Bile acids, which are synthesized from cholesterol by the liver, are chemically transformed along the intestinal tract by the gut microbiota, and the products of these transformations signal through host receptors, affecting overall host health. These transformations include bile acid deconjugation, oxidation, and 7α-dehydroxylation. An understanding of the biogeography of bile acid transformations in the gut is critical because deconjugation is a prerequisite for 7α-dehydroxylation and because most gut microorganisms harbor bile acid transformation capacity. Here, we used a coupled metabolomic and metaproteomic approach to probe in vivo activity of the gut microbial community in a gnotobiotic mouse model. Results revealed the involvement of Clostridium scindens in 7α-dehydroxylation, of the genera Muribaculum and Bacteroides in deconjugation, and of six additional organisms in oxidation (the genera Clostridium, Muribaculum, Bacteroides, Bifidobacterium, Acutalibacter, and Akkermansia). Furthermore, the bile acid profile in mice with a more complex microbiota, a dysbiosed microbiota, or no microbiota was considered. For instance, conventional mice harbor a large diversity of bile acids, but treatment with an antibiotic such as clindamycin results in the complete inhibition of 7α-dehydroxylation, underscoring the strong inhibition of organisms that are capable of carrying out this process by this compound. Finally, a comparison of the hepatic bile acid pool size as a function of microbiota revealed that a reduced microbiota affects host signaling but not necessarily bile acid synthesis. In this study, bile acid transformations were mapped to the associated active microorganisms, offering a systematic characterization of the relationship between microbiota and bile acid composition.

Clostridium difficile infection in an academic medical center in Saudi Arabia: prevalence and risk factors

BACKGROUND

Clostridium difficile infection is one of the most common causes of diarrhea in healthcare facilities. More studies are needed to identify patients at high risk of C difficile infection in our community.

OBJECTIVES

Estimate the prevalence of C difficile infection among adult patients and evaluate the risk factors associated with infection.

DESIGN

Retrospective record review.

SETTING

Tertiary academic medical center in Jeddah.

PATIENTS AND METHODS

Eligible patients were adults (≥18 years old) with confirmed C difficile diagnosis between January 2013 and May 2018.

MAIN OUTCOME MEASURES

Prevalence rate and types of risk factors.

SAMPLE SIZE

Of 1886 records, 129 patients had positive lab results and met the inclusion criteria.

RESULTS

The prevalence of C difficile infection in our center over five years was 6.8%. The mean (SD) age was 56 (18) years, and infection was more prevalent in men (53.5%) than in women (46.5%). The most common risk factors were use of proton-pump inhibitors (PPI) and broad-spectrum antibiotics. The overlapping exposure of both PPIs and broad-spectrum antibiotics was 56.6%. There was no statistically significant difference between the type of PPI (P=.254) or antibiotic (P=.789) and the onset of C difficile infection.

CONCLUSION

The overall C difficile infection prevalence in our population was low compared to Western countries. The majority of the patients who developed C difficile infection were using PPIs and/or antibiotics. No differences were observed in the type of antibiotic or PPI and the onset of C difficile infection development. Appropriate prescribing protocols for PPIs and antibiotics in acute settings are needed.

LIMITATIONS

Single center and retrospective design.

CONFLICT OF INTEREST

None.

Impact of antimicrobial therapy on the gut microbiome

The gut microbiome is now considered an organ unto itself and plays an important role in health maintenance and recovery from critical illness. The commensal organisms responsible for the framework of the gut microbiome are valuable in protection against disease and various physiological tasks. Critical illness and the associated interventions have a detrimental impact on the microbiome. While antimicrobials are one of the fundamental and often life-saving modalities in septic patients, they can also pave the way for subsequent harm because of the resulting damage to the gut microbiome. Contributing to many of the non-specific signs and symptoms of sepsis, the balance between the overuse of antimicrobials and the clinical need in these situations is often difficult to delineate. Given the potency of antimicrobials utilized to treat septic patients, the effects on the gut microbiome are often rapid and long-lasting, in which case full recovery may never be observed. The overgrowth of opportunistic pathogens is of significant concern as they can lead to infections that become increasingly difficult to treat. Continued research to understand the disturbances within the gut microbiome of critically ill patients and their outcomes is essential to help develop future therapies to circumvent damage to, or restore, the microbiome. In this review, we discuss the impact of the antimicrobials often used for the treatment of sepsis on the gut microbiota.

The Effect of Saccharomyces boulardii Primary Prevention on Risk of Hospital-onset Clostridioides difficile Infection in Hospitalized Patients Administered Antibiotics Frequently Associated With C. difficile Infection

Background

Hospital-onset Clostridioides difficile infection (HO-CDI) is a costly problem leading to readmissions, morbidity, and mortality. We evaluated the effect of a single probiotic strain, Saccharomyces boulardii, at a standardized dose on the risk of HO-CDI within hospitalized patients administered antibiotics frequently associated with HO-CDI.

Methods

This retrospective cohort study merged hospital prescribing data with HO-CDI case data. The study assessed patients hospitalized from January 2016 through March 2017 who were administered at least 1 dose of an antibiotic frequently associated with HO-CDI during hospitalization. Associations between S. boulardii administration, including timing, and HO-CDI incidence were evaluated by multivariable logistic regression.

Results

The study included 8763 patients. HO-CDI incidence was 0.66% in the overall cohort. HO-CDI incidence was 0.56% and 0.82% among patients coadministered S. boulardii with antibiotics and not coadministered S. boulardii, respectively. In adjusted analysis, patients coadministered S. boulardii had a reduced risk of HO-CDI (odds ratio [OR], 0.57 [95% confidence interval {CI}, .33–.96]; P = .04) compared to patients not coadministered S. boulardii. Patients coadministered S. boulardii within 24 hours of antibiotic start demonstrated a reduced risk of HO-CDI (OR, 0.47 [95% CI, .23–.97]; P = .04) compared to those coadministered S. boulardii after 24 hours of antibiotic start.

Conclusions

Saccharomyces boulardii administered to hospitalized patients prescribed antibiotics frequently linked with HO-CDI was associated with a reduced risk of HO-CDI.

Simulating transmission of ESKAPE pathogens plus C. difficile in relevant clinical scenarios

BACKGROUND

The prevalence of healthcare-acquired infections (HAI) and rising levels of antimicrobial resistance places significant economic and public health burdens on modern healthcare systems. A group of highly drug resistant pathogens known as the ESKAPE pathogens, along with C. difficile, are the leading causes of HAIs. Interactions between patients, healthcare workers, and environmental conditions impact disease transmission. Studying pathogen transfer under varying contact scenarios in a controlled manner is critical for understanding transmission and disinfectant strategies. In lieu of human subject research, this method has the potential to contribute to modeling the routes of pathogen transmission in healthcare settings.

METHODS

To overcome these challenges, we have developed a method that utilizes a synthetic skin surrogate to model both direct (skin-to-skin) and indirect (skin-to fomite-to skin) pathogen transfer between infected patients and healthy healthcare workers. This surrogate material includes a background microbiome community simulating typical human skin flora to more accurately mimic the effects of natural flora during transmission events.

RESULTS

We demonstrate the ability to modulate individual bacterial concentrations within this microbial community to mimic bacterial concentrations previously reported on the hands of human subjects. We also explore the effect of various decontamination approaches on pathogen transfer between human subjects, such as the use of handwashing or surface disinfectants. Using this method, we identify a potential outlier, S. aureus, that may persist and retain viability in specific transfer conditions better than the overall microbial community during decontamination events.

CONCLUSIONS

Our work describes the development of an in vitro method that uses a synthetic skin surrogate with a defined background microbiota to simulate skin-to-skin and skin-to fomite-to skin contact scenarios. These results illustrate the value of simulating a holistic microbial community for transfer studies by elucidating differences in different pathogen transmission rates and resistance to common decontamination practices. We believe this method will contribute to improvements in pathogen transmission modeling in healthcare settings and increase our ability to assess the risk associated with HAIs, although additional research is required to establish the degree of correlation of pathogen transmission by skin or synthetic alternatives.

Modeling inpatient and outpatient antibiotic stewardship interventions to reduce the burden of Clostridioides difficile infection in a regional healthcare network

Antibiotic exposure can lead to unintended outcomes, including drug-drug interactions, adverse drug events, and healthcare-associated infections like Clostridioides difficile infection (CDI). Improving antibiotic use is critical to reduce an individual's CDI risk. Antibiotic stewardship initiatives can reduce inappropriate antibiotic prescribing (e.g., unnecessary antibiotic prescribing, inappropriate antibiotic selection), impacting both hospital (healthcare)-onset (HO)-CDI and community-associated (CA)-CDI. Previous computational and mathematical modeling studies have demonstrated a reduction in CDI incidence associated with antibiotic stewardship initiatives in hospital settings. Although the impact of antibiotic stewardship initiatives in long-term care facilities (LTCFs), including nursing homes, and in outpatient settings have been documented, the effects of specific interventions on CDI incidence are not well understood. We examined the relative effectiveness of antibiotic stewardship interventions on CDI incidence using a geospatially explicit agent-based model of a regional healthcare network in North Carolina. We simulated reductions in unnecessary antibiotic prescribing and inappropriate antibiotic selection with intervention scenarios at individual and network healthcare facilities, including short-term acute care hospitals (STACHs), nursing homes, and outpatient locations. Modeled antibiotic prescription rates were calculated using patient-level data on antibiotic length of therapy for the 10 modeled network STACHs. By simulating a 30% reduction in antibiotics prescribed across all inpatient and outpatient locations, we found the greatest reductions on network CDI incidence among tested scenarios, namely a 17% decrease in HO-CDI incidence and 7% decrease in CA-CDI. Among intervention scenarios of reducing inappropriate antibiotic selection, we found a greater impact on network CDI incidence when modeling this reduction in nursing homes alone compared to the same intervention in STACHs alone. These results support the potential importance of LTCF and outpatient antibiotic stewardship efforts on network CDI burden and add to the evidence that a coordinated approach to antibiotic stewardship across multiple facilities, including inpatient and outpatient settings, within a regional healthcare network could be an effective strategy to reduce network CDI burden.

Impact of a Diagnosis-Centered Antibiotic Stewardship on Incident Clostridioides difficile Infections in Older Inpatients: An Observational Study

In 2015, a major increase in incident hospital-onset Clostridioides difficile infections (HO-CDI) in a geriatric university hospital led to the implementation of a diagnosis-centered antibiotic stewardship program (ASP). We aimed to evaluate the impact of the ASP on antibiotic consumption and on HO-CDI incidence. The intervention was the arrival of a full-time infectiologist in the acute geriatric unit in May 2015, followed by the implementation of new diagnostic procedures for infections associated with an antibiotic withdrawal policy. Between 2015 and 2018, the ASP was associated with a major reduction in diagnoses for inpatients (23% to 13% for pneumonia, 24% to 13% for urinary tract infection), while median hospital stays and mortality rates remained stable. The reduction in diagnosed bacterial infections was associated with a 45% decrease in antibiotic consumption in the acute geriatric unit. HO-CDI incidence also decreased dramatically from 1.4‰ bed-days to 0.8‰ bed-days in the geriatric rehabilitation unit. The ASP focused on reducing the overdiagnosis of bacterial infections in the acute geriatric unit was successfully associated with both a reduction in antibiotic use and a clear reduction in the incidence of HO-CDI in the geriatric rehabilitation unit.

The gut microbiome's role in the development, maintenance, and outcomes of sepsis

The gut microbiome regulates a number of homeostatic mechanisms in the healthy host including immune function and gut barrier protection. Loss of normal gut microbial structure and function has been associated with diseases as diverse as Clostridioides difficile infection, asthma, and epilepsy. Recent evidence has also demonstrated a link between the gut microbiome and sepsis. In this review, we focus on three key areas of the interaction between the gut microbiome and sepsis. First, prior to sepsis onset, gut microbiome alteration increases sepsis susceptibility through several mechanisms, including (a) allowing for expansion of pathogenic intestinal bacteria, (b) priming the immune system for a robust pro-inflammatory response, and (c) decreasing production of beneficial microbial products such as short-chain fatty acids. Second, once sepsis is established, gut microbiome disruption worsens and increases susceptibility to end-organ dysfunction. Third, there is limited evidence that microbiome-based therapeutics, including probiotics and selective digestive decontamination, may decrease sepsis risk and improve sepsis outcomes in select patient populations, but concerns about safety have limited uptake. Case reports of a different microbiome-based therapy, fecal microbiota transplantation, have shown correlation with gut microbial structure restoration and decreased inflammatory response, but these results require further validation. While much of the evidence linking the gut microbiome and sepsis has been established in pre-clinical studies, clinical evidence is lacking in many areas. To address this, we outline a potential research agenda for further investigating the interaction between the gut microbiome and sepsis.

Temporal change of risk factors in hospital-acquired Clostridioides difficile infection using time-trend analysis

OBJECTIVE

Given recent changes in the epidemiology of Clostridioides difficile infection (CDI) and prevention efforts, we investigated temporal changes over a period of 11 years (2006-2016) in incidence and risk factors for CDI.

DESIGN

Retrospective matched case-control study.

SETTING/PATIENTS

Pediatric and adult inpatients (n = 694,849) discharged from 3 hospitals (tertiary and quaternary care, community, and pediatric) in a large, academic health center in New York City.

METHODS

Risk factors were identified in cases and controls matched by length of stay at a ratio of 1:4. A Cochran-Armitage or Mann-Kendall test was used to investigate trends of incidence and risk factors.

RESULTS

Of 694,849 inpatients, 6,038 (0.87%) had CDI: 44% of these cases were hospital acquired (HA-CDI) and 56% were community acquired (CA-CDI). We observed temporal downward trends in HA-CDI (-0.03% per year) and upward trends in CA-CDI (+0.04% per year). Over time, antibiotics were administered to more patients (+3% per year); the use of high-risk antibiotics declined (-1.2% per year); and antibiotic duration increased in patients with HA-CDI (+4.4% per year). Fewer proton-pump inhibitors and more histamine-2 blockers were used (-3.8% and +7.3% per year, respectively; all Ptrend <.05).

CONCLUSIONS

Although the incidence of HA-CDI decreased over time, CA-CDI simultaneously increased. Continued efforts to assure judicious use of antibiotics in inpatient and community settings is clearly vital. Measuring the actual the level of exposure of an antibiotic (incidence density) should be used for ongoing surveillance and assessment.

Clostridioides difficile infection after pneumonia in older patients: Which antibiotic is at lower risk?

BACKGROUND

Clostridioides difficile infection (CDI) is a frequent and severe complication of antibiotic treatment in older patients hospitalized for acute pneumonia (AP).

AIMS

We aimed to assess the burden and risk factors of CDI and to determine which of the usual antibiotics regimens is at lower risk for post-AP CDI incidence.

METHODS

Among patients aged >75y hospitalized for AP in all departments of a university hospital between 2007 and 2017, all the 92 patients developing a CDI were compared with 213 patients without CDI. Factors associated with 1) in-hospital and one-year mortality, 2) CDI incidence were assessed using logistic regression models.

FINDINGS

In patients with and without CDI after AP, mortality rates were respectively at 34% vs 20% in hospital and 63% vs 42% at one-year. After adjustment for confounders, CDI was associated with a two-fold risk of in-hospital and one-year mortality after pneumonia (Respective Odds Ratio (95% Confidence Interval), OR (95%CI): 1.95 (1.06-3.58) and 2.02 (1.43-7.31)). High number of antibiotics (Per antibiotic, OR (95%CI): 1.89 (1.18-3.06)), rather than antibiotics duration (Per day, OR 95%CI): 1.04 (0.96-1.11)) was associated with a higher risk of CDI. Compared with other antibiotics, use of penicillin + beta-lactamase inhibitors was associated with a lower risk of CDI (OR (95%CI): 0.43 (0.19 -0.99)) CONCLUSION: In older inpatients, CDI highly increase the burden of AP at both short and long term. If confirmed, these results suggest the preferential use of penicillin + beta-lactamase inhibitors for a lower incidence of CDI in older inpatients with AP.

Considering the Immune System during Fecal Microbiota Transplantation for Clostridioides difficile Infection

Our understanding and utilization of fecal microbiota transplantation (FMT) has jump-started over the past two decades. Recent technological advancements in sequencing and metabolomics have allowed for better characterization of our intestinal microbial counterparts, triggering a surge of excitement in the fields of mucosal immunology and microbiology. This excitement is well founded, as demonstrated by 90% relapse-free cure rates in FMT treatment for recurrent Clostridioides difficile infections. Growing evidence suggests that in addition to bacterial factors, the host immune response during C. difficile infection greatly influences disease severity. In this review, we discuss recent advancements in understanding the interplay between immune cells and the microbiota and how they may relate to recovery from C. difficile through FMT therapy.