Impact of Clostridium difficile infection caused by the NAP1/RT027 strain on severity and recurrence during an outbreak and transition to endemicity in a Mexican tertiary care center

Clostridioides Difficile in Latin America: An Epidemiological Overview

Clostridioides difficile infection is one of the most significant causes of nosocomial diarrhea associated with antibiotic use worldwide. In recent years, the incidence of Clostridioides difficile infection in Latin American countries has increased due to the emergence and spread of epidemic Clostridioides difficile strains, such as RT027/NAP1/ST1, RT078/ST11, and RT017/ST37; additionally, endemic multi-drug-resistant strains have recently appeared due to the lack of heterogeneous diagnostic algorithms and guidelines for antibiotic use in each country. The aim of this review is to present the latest information regarding Clostridioides difficile and emphasize the importance of epidemiological surveillance of this pathogen in Latin American countries.

Low-Toxin Clostridioides difficile RT027 Strains Exhibit Robust Virulence

Clostridioides difficile is a leading cause of healthcare-associated infections worldwide. Currently, there is a lack of consensus for an optimal diagnostic method for C. difficile infection (CDI). Multi-step diagnostic algorithms use enzyme immunosorbent analysis (EIA)-based detection of C. difficile toxins TcdA/TcdB in stool, premised on the rationale that EIA toxin-negative (Tox⁻) patients have less severe disease and shorter diarrhoea duration. The aim of this study was to characterize toxigenic (i.e. tcdA/tcdB-positive) C. difficile strains isolated from diarrheic patient stool with an EIA Tox⁻ (i.e. “discrepant”) CDI diagnostic test result. Recovered strains were DNA fingerprinted (ribotyped), subjected to multiple toxin, genome and proteome evaluations, and assessed for virulence. Overall, of 1243 C. difficile-positive patient stool specimens from Southern Arizona hospitals, 31% were discrepant. For RT027 (the most prevalent ribotype)-containing specimens, 34% were discrepant; the corresponding RT027 isolates were cytotoxic to cultured fibroblasts, but their total toxin levels were comparable to, or lower than, the historic low-toxin-producing C. difficile strain CD630. Nevertheless, these low-toxin RT027 strains (LT-027) exhibited similar lethality to a clade-matched high-toxin RT027 strain in Golden Syrian hamsters, and heightened colonization and persistence in mice. Genomics and proteomics analyses of LT-027 strains identified unique genes and altered protein abundances, respectively, relative to high-toxin RT027 strains. Collectively, our data highlight the robust virulence of LT-027 C. difficile, provide a strong argument for reconsidering the clinical significance of a Tox⁻ EIA result, and underscore the potential limitations of current diagnostic protocols.

Design and characterization of a novel lytic protein against Clostridium difficile

Abstract

Clostridium difficile (C. difficile) is a Gram-positive, spore-forming, toxin-producing anaerobe that can cause nosocomial antibiotic-associated intestinal disease. Autolysin is a lytic enzyme that hydrolyzes peptidoglycans of the bacterial cell wall, with a catalytic domain and cell wall–binding domains, proven to be involved in bacterial cell wall remodeling and cell division. Although autolysins in C. difficile have been reported, the autolysins have failed to yield impressive results when used as exogenous lytic agents. In this study, we expressed and characterized the binding domains (Cwp19-BD and Acd-BD) and catalytic domains (Cwp19-CD, Acd-CD, and Cwl-CD) of C. difficile autolysins, and the domains with the best binding specificity and lytic activity were selected towards C. difficile to design a novel lytic protein Cwl-CWB2. Cwl-CWB2 showed good biosafety with significantly low hemolysis and without cytotoxicity. The results of fluorescence analysis and lytic assay demonstrated that Cwl-CWB2 has higher binding specificity and stronger lytic activity with a minimum inhibitory concentration at 13.39 ± 5.80 μg/mL against living C. difficile cells, which is significantly stronger than commercial lysozyme (3333.33 ± 1443.37 μg/mL) and other reported C. difficile autolysins. Besides, Cwl-CWB2 exhibited good stability as about 75% of the lytic activity was still retained when incubated at 37 °C for 96 h, which is considered to be a potential antimicrobial agent to combat C. difficile.

Key points

• Several binding domains and catalytic domains, deriving from several Clostridium difficile autolysins, were expressed, purified, and functionally characterized.

• A novel C. difficile lytic protein Cwl-CWB2 was designed from C. difficile autolysins.

• The binding specificity and lytic activity of Cwl-CWB2 against C. difficile showed advantages compared with other reported C. difficile autolysins.

• Cwl-CWB2 exhibited significantly low hemolysis and cytotoxicity against normal-derived colon mucosa 460 cell.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00253-022-12010-0.

Can prediction scores be used to identify patients at risk of Clostridioides difficile infection?

PURPOSE OF REVIEW

To describe the current state of literature on modeling risk of incident and recurrent Clostridioides difficile infection (iCDI and rCDI), to underscore limitations, and to propose a path forward for future research.

RECENT FINDINGS

There are many published risk factors and models for both iCDI and rCDI. The approaches include scores with a limited list of variables designed to be used at the bedside, but more recently have also included automated tools that take advantage of the entire electronic health record. Recent attempts to externally validate scores have met with mixed success.

SUMMARY

For iCDI, the performance largely hinges on the incidence, which even for hospitalized patients can be low (often <1%). Most scores fail to achieve high accuracy and/or are not externally validated. A challenge in predicting rCDI is the significant overlap with risk factors for iCDI, reducing the discriminatory ability of models. Automated electronic health record-based tools show promise but portability to other centers is challenging. Future studies should include external validation and consider biomarkers to augment performance.

European Society of Clinical Microbiology and Infectious Diseases: 2021 update on the treatment guidance document for Clostridioides difficile infection in adults

SCOPE

In 2009, the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) published the first treatment guidance document for Clostridioides difficile infection (CDI). This document was updated in 2014. The growing literature on CDI antimicrobial treatment and novel treatment approaches, such as faecal microbiota transplantation (FMT) and toxin-binding monoclonal antibodies, prompted the ESCMID study group on C. difficile (ESGCD) to update the 2014 treatment guidance document for CDI in adults.

METHODS AND QUESTIONS

Key questions on CDI treatment were formulated by the guideline committee and included: What is the best treatment for initial, severe, severe-complicated, refractory, recurrent and multiple recurrent CDI? What is the best treatment when no oral therapy is possible? Can prognostic factors identify patients at risk for severe and recurrent CDI and is there a place for CDI prophylaxis? Outcome measures for treatment strategy were: clinical cure, recurrence and sustained cure. For studies on surgical interventions and severe-complicated CDI the outcome was mortality. Appraisal of available literature and drafting of recommendations was performed by the guideline drafting group. The total body of evidence for the recommendations on CDI treatment consists of the literature described in the previous guidelines, supplemented with a systematic literature search on randomized clinical trials and observational studies from 2012 and onwards. The Grades of Recommendation Assessment, Development and Evaluation (GRADE) system was used to grade the strength of our recommendations and the quality of the evidence. The guideline committee was invited to comment on the recommendations. The guideline draft was sent to external experts and a patients' representative for review. Full ESCMID endorsement was obtained after a public consultation procedure.

RECOMMENDATIONS

Important changes compared with previous guideline include but are not limited to: metronidazole is no longer recommended for treatment of CDI when fidaxomicin or vancomycin are available, fidaxomicin is the preferred agent for treatment of initial CDI and the first recurrence of CDI when available and feasible, FMT or bezlotoxumab in addition to standard of care antibiotics (SoC) are preferred for treatment of a second or further recurrence of CDI, bezlotoxumab in addition to SoC is recommended for the first recurrence of CDI when fidaxomicin was used to manage the initial CDI episode, and bezlotoxumab is considered as an ancillary treatment to vancomycin for a CDI episode with high risk of recurrence when fidaxomicin is not available. Contrary to the previous guideline, in the current guideline emphasis is placed on risk for recurrence as a factor that determines treatment strategy for the individual patient, rather than the disease severity.

Production of p-cresol by Decarboxylation of p-HPA by All Five Lineages of Clostridioides difficile Provides a Growth Advantage

Clostridioides difficile is the leading cause of antibiotic-associated diarrhea and is capable of causing severe symptoms, such as pseudomembranous colitis and toxic megacolon. An unusual feature of C. difficile is the distinctive production of high levels of the antimicrobial compound para-cresol. p-Cresol production provides C. difficile with a competitive colonization advantage over gut commensal species, in particular, Gram-negative species. p-Cresol is produced by the conversion of para-hydroxyphenylacetic acid (p-HPA) via the actions of HpdBCA decarboxylase coded by the hpdBCA operon. Host cells and certain bacterial species produce p-HPA; however, the effects of p-HPA on the viability of C. difficile and other gut microbiota are unknown. Here we show that representative strains from all five C. difficile clades are able to produce p-cresol by two distinct mechanisms: (i) via fermentation of p-tyrosine and (ii) via uptake and turnover of exogenous p-HPA. We observed strain-specific differences in p-cresol production, resulting from differential efficiency of p-tyrosine fermentation; representatives of clade 3 (CD305) and clade 5 (M120) produced the highest levels of p-cresol via tyrosine metabolism, whereas the toxin A-/B+ isolate from clade 4 (M68) produced the lowest level of p-cresol. All five lineages share at least 97.3% homology across the hpdBCA operon, responsible for decarboxylation of p-HPA to p-cresol, suggesting that the limiting step in p-cresol production may result from tyrosine to p-HPA conversion. We identified that elevated intracellular p-HPA, modulated indirectly via CodY, controls p-cresol production via inducing the expression of HpdBCA decarboxylase ubiquitously in C. difficile populations. Efficient turnover of p-HPA is advantageous to C. difficile as p-HPA has a deleterious effect on the growth of C. difficile and other representative Gram-negative gut bacteria, transduced potentially by the disruption of membrane permeability and release of intracellular phosphate. This study provides insights into the importance of HpdBCA decarboxylase in C. difficile pathogenesis, both in terms of p-cresol production and detoxification of p-HPA, highlighting its importance to cell survival and as a highly specific therapeutic target for the inhibition of p-cresol production across C. difficile species.

Prognostic factors for severe and recurrent Clostridioides difficile infection: a systematic review

OBJECTIVES

Clostridioides difficile infection (CDI), its subsequent recurrences (rCDIs), and severe CDI (sCDI) provide a significant burden for both patients and the healthcare system. Identifying patients diagnosed with initial CDI who are at increased risk of developing sCDI/rCDI could lead to more cost-effective therapeutic choices. In this systematic review we aimed to identify clinical prognostic factors associated with an increased risk of developing sCDI or rCDI.

METHODS

PubMed, Embase, Emcare, Web of Science and COCHRANE Library databases were searched from database inception through March, 2021. The study eligibility criteria were cohort and case-control studies. Participants were patients ≥18 years old diagnosed with CDI, in which clinical or laboratory factors were analysed to predict sCDI/rCDI. Risk of bias was assessed by using the Quality in Prognostic Research (QUIPS) tool and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool modified for prognostic studies. Study selection was performed by two independent reviewers. Overview tables of prognostic factors were constructed to assess the number of studies and the respective effect direction and statistical significance of an association.

RESULTS

136 studies were included for final analysis. Greater age and the presence of multiple comorbidities were prognostic factors for sCDI. Identified risk factors for rCDI were greater age, healthcare-associated CDI, prior hospitalization, proton pump inhibitors (PPIs) started during or after CDI diagnosis, and previous rCDI.

CONCLUSIONS

Prognostic factors for sCDI and rCDI could aid clinicians to make treatment decisions based on risk stratification. We suggest that future studies use standardized definitions for sCDI/rCDI and systematically collect and report the risk factors assessed in this review, to allow for meaningful meta-analysis of risk factors using data of high-quality trials.

Microbiological features, epidemiology, and clinical presentation of Clostridioidesdifficile strains from MLST Clade 2: A narrative review

Clostridioides difficile is an emerging One Health pathogen and a common etiologic agent of diarrhea, both in healthcare settings and the community. This bacterial species is highly diverse, and its global population has been classified in eight clades by multilocus sequence typing (MLST). The C. difficile MLST Clade 2 includes the NAP1/RT027/ST01 strain, which is highly recognized due to its epidemicity and association with severe disease presentation and mortality. By contrast, the remaining 83 sequence types (STs) that compose this clade have received much less attention. In response to this shortcoming, we reviewed articles published in English between 1999 and 2020 and collected information for 27 Clade 2 STs, with an emphasis on STs 01, 67, 41 and 188/231/365. Our analysis provides evidence of large phenotypic differences that preclude support of the rather widespread notion that ST01 and Clade 2 strains are "hypervirulent". Moreover, it revealed a profound lack of (meta)data for nearly 70% of the Clade 2 STs that have been identified in surveillance efforts. Targeted studies aiming to relate wet-lab and bioinformatics results to patient and clinical parameters should be performed to gain a more in-depth insight into the biology of this intriguing group of C. difficile isolates.

Proton pump inhibitor use and risk for recurrent Clostridioides difficile infection: a systematic review and meta-analysis

OBJECTIVES

Proton pump inhibitor (PPI) therapy is a potentially modifiable risk factor for recurrent Clostridioides difficile infection (CDI). Citing an absence of clinical trials, many guidelines do not provide recommendations for addressing PPI management. Our aim was to perform an updated systematic review and meta-analysis evaluating the association between PPI use and recurrent CDI addressing prior methodological limitations.

METHODS

Data sources were MEDLINE and EMBASE. Eligible studies were cohort and case-control studies; there were no restrictions on study setting or duration of follow-up. Participants were adults with prior CDI who did or did not receive PPI therapy and were assessed for recurrent CDI. Summary (unadjusted) odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random effects model. Prespecified subgroup analyses were performed to explore heterogeneity including study design, study quality, duration of follow-up, adjustment for confounders, and outcome definition.

RESULTS

Sixteen studies were included in the meta-analysis, comprising 57 477 patients with CDI, of whom 6870 (12%) received PPIs. The rate of recurrent CDI was 24% in patients treated with PPIs versus 18% in those who were not. A meta-analysis that pooled unadjusted odds ratios demonstrated higher odds of recurrent CDI in patients who received PPIs (OR 1.69, 95%CI 1.46-1.96) versus those who did not. There was moderate heterogeneity between studies (I2 56%); however, a sensitivity analysis restricted to studies with 56 days of follow-up substantially reduced the heterogeneity (OR 1.59, 95%CI 1.36-1.85; I2 12%). An analysis restricted to multivariate studies that combined adjusted ORs also demonstrated higher odds of recurrent CDI in patients who received PPIs (OR 1.49, 95%CI 1.12-2.00). No publication bias was identified.

CONCLUSIONS

We found significantly higher odds of recurrent CDI among users of PPIs that persisted across multiple sensitivity analyses. These results support stronger recommendations for PPI stewardship at CDI diagnosis.

The largely unnoticed spread of Clostridioides difficile PCR ribotype 027 in Germany after 2010

In recent decades, incidence and severity of Clostridioides difficile infection (CDI) has increased dramatically, coinciding with the emergence of hypervirulent strains such as PCR ribotype 027 (RT027). Data on prevalence of distinct C. difficile strains in random CDI cases in Germany are scarce. The aim of this review was to obtain an overview of prevalence and geographical distribution of RT027 among clinical C. difficile isolates from random cases in non-outbreak settings in hospitals in Germany. For this purpose, we performed a literature review on reported cases of C. difficile RT027 in Germany between 2007 and 2019 in three databases (PubMed, Embase and LIVIVO) and conference proceedings. Studies with selection bias for RT027 (e.g. clinical severity, outbreak reports) were excluded. A total of 304 records were screened, from which 21 were included in this analysis. The nationwide prevalence of RT027 in Germany was <1% prior to 2010 but increased continuously thereafter, reaching 21.7% in 2013. The regional prevalence varied markedly between federal states, higher prevalence was reported from North Rhine-Westphalia (37.4%) and Saxony (31.8%) in 2013-2015. However, data on C. difficile RT027 were not available from almost half of the federal states and were scarce at the national level. Our data suggest a remarkable spread of RT027 in Germany during the past decade, which has remained rather unnoticed so far. A national program for molecular surveillance of C. difficile is required to monitor the changing epidemiology of CDI and to adjust the prevention and control measures.

Clostridioides difficile-associated diarrhea in surgical service patients in Mexico

INTRODUCTION

Clostridioides difficile is the first cause of healthcare-associated diarrhea in developed countries. In recent years the incidence of C. difficile infection (CDI) has increased worldwide. There is not much information on the topic in Mexico, and little is known about the risk factors for the infection in patients that are hospitalized in surgical services.

MATERIALS AND METHODS

A case-control study was conducted that compared the epidemiologic findings and risk factors between surgical patients with PCR-confirmed CDI, surgical patients with diarrhea and a negative PCR test, and surgical patients with no diarrhea. The statistical analysis was carried out using the SPSS version 22.0 program.

RESULTS

The majority of the surgical patients with CDI belonged to the areas of neurosurgery, cardiac surgery, orthopedics, and general surgery. A total of 53% of the CDI cases were associated with the hypervirulent CD NAP1/027 strain. The presence of mucus in stools (OR: 1.5, P=.001), fever (OR: 1.4, P=.011), leukocytes in stools (OR: 3.2, P<.001), hospitalization within the past 12weeks (OR: 2.0, P<.001), antibiotic use (OR: 1.3, P=.023), and ceftriaxone use (OR: 1.4, P=.01) were independent risk factors for the development of CDI.

CONCLUSIONS

C. difficile-induced diarrhea in the surgical services is frequent at the Hospital Civil de Guadalajara "Fray Antonio Alcalde".

Consensus on the prevention, diagnosis, and treatment of Clostridium difficile infection

In recent decades, Clostridium difficile infection (CDI) has become a worldwide health problem. Mexico is no exception, and therefore the Asociación Mexicana de Gastroenterología brought together a multidisciplinary group (gastroenterologists, endoscopists, internists, infectious disease specialists, and microbiologists) to carry out the "Consensus on the prevention, diagnosis, and treatment of Clostridium difficile infection", establishing useful recommendations (in relation to the adult population) for the medical community. Said recommendations are presented herein. Among them, it was recognized that CDI should be suspected in subjects with diarrhea that have a history of antibiotic and/or immunosuppressant use, but that it can also be a community-acquired infection. A 2-step diagnostic algorithm was proposed, in which a highly sensitive test, such as glutamate dehydrogenase (GDH), is first utilized, and if positive, confirmed by the detection of toxins through immunoassay or nucleic acid detection tests. Another recommendation was that CDI based on clinical evaluation be categorized as mild-moderate, severe, and complicated severe, given that such a classification enables better therapeutic decisions to be made. In mild-moderate CDI, oral vancomycin is the medication of choice, and metronidazole is recommended as an alternative treatment. In addition, fecal microbiota transplantation was recognized as an efficacious option in patients with recurrence or in the more severe cases of infection, and surgery should be reserved for patients with severe colitis (toxic megacolon), in whom all medical treatment has failed.

PCR based detection of tcdCΔ117 in Clostridium difficile infection identifies patients at risk for recurrence - A hospital-based prospective observational study

OBJECTIVES

Increasing incidence and severity of Clostridium difficile infection (CDI) in the last decades has been attributed to the emergence of hypervirulent C. difficile strain PCR-ribotype 027 (RT027). Commercial multiplex real-time PCR tests allow the presumptive identification of RT027 by detecting a single-base deletion at nt117 in the tcdC gene (tcdCΔ117). The clinical usefulness of the detection of tcdCΔ117 is unclear. Therefore, we evaluated test performance and clinical association of the detection of tcdCΔ117 in patients with CDI in a prospective observational study conducted in a tertiary care hospital in Germany.

METHODS

From June to October 2015, stool from all patients with suspected CDI was tested for C. difficile according to ESCMID guidelines. C. difficile was cultured from positive samples and ribotyping was performed. Clinical data were collected prospectively from all C. difficile positive patients.

RESULTS

From 1121 tested stool samples 107 patients with CDI were included in the study. TcdCΔ117 was detected in 18 (16.8%) of these patients. Multivariable logistic regression analysis revealed an independent association of detection of tcdCΔ117 with a further episode of CDI (OR 14.6; 95% CI 3.6-58.3; p < 0.001) and death within 30 days of the positive test (OR 5.1; 95% CI 1.0-25.7; p = 0.046). As follow up data are limited, it remains unclear, whether the further episode of CDI was due to tcdCΔ117 (recurrence) or another type.

CONCLUSION

In our setting, PCR-based detection of tcdCΔ117 identified patients at risk for recurrent CDI and increased mortality and thus may guide therapeutic choices in CDI patients at the time of diagnosis.

Clostridium Difficile Infection: An Immunological Conundrum

The lack of comprehensive understanding of the way immunity backfires on incidence and complications has made Clostridium difficile infection (CDI), the infectious disease of our times, as evidenced by in the parallel course it follows along epidemic of chronic degenerative diseases. Within these ailments, if as suspected the main effect of Clostridium difficile A and B toxins depends on inflammation, then aberrant immune function due to antibiotics would explain IBD triggering after treatment but also, the higher incidence and mortality surrounding disorders that are inflammatory and/or that show abatement of neutrophils. This review will discuss severity of the disease in terms of challenges to immunity during the progression of acute illness. We will identify the common signals in the communication between microbiota and inflammatory cells, as well as the sequestration of the regulatory network by Clostridium difficile, which leads to tissue damage and prevents its elimination from intestinal lumen.

Factors associated with an outbreak of hospital-onset, healthcare facility-associated Clostridium difficile infection (HO-HCFA CDI) in a Mexican tertiary care hospital: A case-control study

Objective

To identify clinical and environmental factors associated with an outbreak of hospital-onset, healthcare facility-associated Clostridium difficile infection (HO-HCFA CDI).

Design

Case-control study.

Setting

Public, acute care, academic tertiary referral center in Mexico.

Patients

Adults hospitalized ≥48 hours between January 2015 and December 2016 were included. Cases were patients with a first episode of HO-HCFA CDI. Controls were patients with any other diagnosis; they were randomly selected from the hospital discharge database and matched in a 1:2 manner according to the date of diagnosis of case ± 10 days. Variables with p<0.1 were considered for multivariable analysis.

Results

One hundred and fifty-five cases and 310 controls were included. Variables independently associated with HO-HCFA CDI were: exposure to both ciprofloxacin and proton pump inhibitor (PPI) within the last 3 months (OR = 8.07, 95% CI = 1.70–38.16), febrile neutropenia (OR = 4.61, 95% CI = 1.37–15.46), intraabdominal infection (OR = 2.06, 95% CI = 0.95–4.46), referral from other hospitals (OR = 1.99, 95% CI = 0.98–4.05) and an increasing number of antibiotics previously used (OR = 1.28, 95% CI = 1.13–1.46).

Conclusions

Multiple factors were found to be associated with the first episode of HO-HCFA CDI in the setting of an outbreak; of the modifiable risk factors, prior exposure to both ciprofloxacin and PPI was the most important. Referral from other hospitals was an environmental risk factor that deserves further study.