Japanese Clinical Practice Guidelines for Management of Clostridioides (Clostridium) difficile infection

Epidemiological Study on Case Definition of Methicillin-Resistant Staphylococcus aureus Enteritis

Background

Methicillin-resistant Staphylococcus aureus (MRSA) enteritis is a condition in which MRSA grows abnormally in the intestine after administration of antimicrobial agents, resulting in enteritis. Patients with MRSA detected in stool culture tests are often diagnosed with MSRA enteritis. However, uncertainty remains in the diagnostic criteria; therefore, we conducted epidemiological studies to define these cases.

Patients and Methods

Patients who tested positive for MRSA by stool culture using selective media 48 h after admission to Kochi Medical School Hospital between April 1, 2012, and December 31, 2022, and did not meet the exclusion criteria were included. We defined MRSA enteritis (Group A) as cases that were responsive to treatment with vancomycin hydrochloride powder, had a Bristol Stool Scale of ≥ 5, and a stool frequency of at least three times per day; all others were MRSA carriers (Group B). Multivariate analysis was performed to risk factors associated with MRSA enteritis.

Results

Groups A and B included 18 (25.4%) and 53 (74.6%) patients, respectively. Multivariate logistic regression analysis showed that a white blood cell count of > 10000/µL (odds ratio [OR], 5.50; 95% confidence interval [CI], 1.12-26.9), MRSA count of ≥ 2+ in stool cultures (OR, 8.91; 95% CI, 1.79-44.3), and meropenem administration within 1 month of stool specimen submission (OR, 7.47; 95% CI, 1.66-33.6) were risk factors of MRSA enteritis.

Conclusion

The case definitions reviewed for MRSA enteritis may be useful as diagnostic criteria.

Fighting against Clostridioides difficile infection: Current medications

Clostridioides difficile (formerly Clostridium difficile) has been regarded as an 'urgent threat' and a significant global health problem, as life-threatening diarrhoea and refractory recurrence are common in patients with C. difficile infection (CDI). Unfortunately, the available anti-CDI drugs are limited. Recent guidelines recommend fidaxomicin and vancomycin as first-line drugs to treat CDI, bezlotoxumab to prevent recurrence, and faecal microbiota transplantation for rescue treatment. Currently, researchers are investigating therapeutic antibacterial drugs (e.g. teicoplanin, ridinilazole, ibezapolstat, surotomycin, cadazolid, and LFF571), preventive medications against recurrence (e.g. Rebyota, Vowst, VP20621, VE303, RBX7455, and MET-2), primary prevention strategies (e.g. vaccine, ribaxamase, and DAV132) and other anti-CDI medications in the preclinical stage (e.g. Raja 42, Myxopyronin B, and bacteriophage). This narrative review summarises current medications, including newly marketed drugs and products in development against CDI, to help clinicians treat CDI appropriately and to call for more research on innovation.

Derivation of clinical predictive factors (CHIEF) for first recurrent Clostridioides difficile infection

BACKGROUND

Current models for predicting Clostridioides difficile infection (CDI) recurrence rates have a limited capacity to account for important risk factors. This study developed a clinical prediction rule for CDI recurrence.

METHODS

This retrospective cohort study evaluated 209 patients with CDI at a university hospital in Japan. Logistic regression and receiver operating characteristic curve analyses were performed to identify potential predictors (age, sex, underlying diseases, antibiotic use, acid suppressants, immunosuppressants, CDI history) of CDI recurrence.

RESULTS

Forty-five patients developed recurrent CDI. Univariate analyses identified several significant recurrence predictors (enteral feeding, inflammatory bowel diseases [IBD], community-onset CDI, severe CDI). Enteral feeding (odds ratio: 3.87, 95% confidence interval: 1.75-8.56) and IBD (odds ratio: 7.08, 95% confidence interval: 1.28-39.06) were significant factors in the multivariate analysis. The CHIEF predictive scoring system was developed using 5 relevant variables (carbapenem use, hematologic malignancy, IBD, enteral feeding, fluoroquinolone use); the area under the receiver operating characteristic curve for the CHIEF score was 0.70.

DISCUSSION

The CHIEF score incorporates useful, clinically available factors and could help identify patients at risk of recurrent CDI.

CONCLUSIONS

These findings contribute to the understanding of risk factors associated with CDI recurrence and provide support for the development of prevention strategies.

The burden of Clostridioides difficile infections in South-East Asia and the Western Pacific: A narrative review

BACKGROUND

Clostridioides difficile (formerly Clostridium difficile) is well-documented in Europe and North America to be a common cause of healthcare-associated gastrointestinal tract infections. In contrast, C difficile infection (CDI) is infrequently reported in literature from Asia, which may reflect a lack of clinician awareness. We conducted a narrative review to better understand CDI burden in Asia.

METHODS

We searched the PubMed database for English language articles related to C difficile, Asia, epidemiology, and molecular characteristics (eg, ribotype, antimicrobial resistance).

RESULTS

Fifty-eight articles that met eligibility criteria were included. C difficile prevalence ranged from 7.1% to 45.1 % of hospitalized patients with diarrhea, and toxigenic strains among all C difficile in these patients ranged from 68.2% to 91.9 % in China and from 39.0% to 60.0 % outside of China. Widespread C difficile ribotypes were RT017, RT014/020, RT012, and RT002. Recurrence in patients with CDI ranged from 3.0% to 17.2 %. Patients with CDI typically had prior antimicrobial use recently. High rates of resistance to ciprofloxacin, clindamycin, and erythromycin were frequently reported.

CONCLUSION

The regional CDI burden in Asia is still incompletely documented, seemingly due to low awareness and limited laboratory testing. Despite this apparent under recognition, the current CDI burden highlights the need for broader surveillance and for application of preventative measures against CDI in Asia.

Evaluation of MALDI-TOF mass spectrometry coupled with ClinProTools as a rapid tool for toxin-producing Clostridioides difficile

INTRODUCTION

The performance of MALDI-TOF MS combined with analysis platform for identification of toxin-producing Clostridiodes difficile is yet to be known.

METHODS

Between August 2018 and September 2020, 61 isolates from stool specimens of patients with C. difficile-associated diarrhea were analyzed using the MALDI Biotyper system. A C. difficile toxin-producer detection model was developed using ClinProTools. The model was validated using 28 known strains that differed from the isolates used to develop the model.

RESULTS

The sensitivity and specificity of the Genetic Algorithm (GA) model using isolates grown on Brucella with hemin and vitamin K (BHK) agar plates were 91.7% and 44.4%, respectively. When isolates grown on cycloserine-cefoxitin mannitol agar were analyzed by the model, sensitivity and specificity were 6.3% and 100%, respectively. The GA model using BHK medium showed the highest discriminatory performance in detection of toxin-producing C. difficile. However, a discrepancy in detection of toxin-producing C. difficile was observed in the results generated when the model was being developed and when the model was validated which suggests that incubation conditions may have affected the results.

CONCLUSION

MALDI-TOF analysis using ClinProTools has a potential to be a cost-effective tool for rapid diagnosis and contribute to antimicrobial stewardship by differentiating toxin-producing C. difficile from non-producers.

Oral teicoplanin administration suppresses recurrence of Clostridioides difficile infection: Proof of concept

OBJECTIVES

Teicoplanin is a potential antimicrobial candidate for Clostridioides difficile infection (CDI) treatment. However, the therapeutic potential of teicoplanin against severe CDI has not been clinically proven. In the present study, we investigated the efficacy of oral teicoplanin administration against severe CDI and the recurrence of severe CDI after teicoplanin treatment in a mouse model.

METHODS

A lethal CDI mouse model was established by colonizing the mice with C. difficile ATCC® 43255; they were orally administered teicoplanin (128 mg/kg/d) or vancomycin (160 mg/kg/d) for 10 d, 24 h after C. difficile spore challenge, and physiological and biological responses were monitored for 20 d after the initial antibiotic treatment. We also performed the in vitro time-kill assay and determined minimum inhibitory concentration (MIC), post-antibiotic effect, and toxin production with antibiotic exposure.

RESULTS

The therapeutic response (survival rates, body weight change, clinical sickness score grading, C. difficile load, and toxin titer in feces) of oral teicoplanin administration was comparable to that of oral vancomycin administration in the lethal CDI mouse model. Moreover, teicoplanin treatment suppressed the re-onset of diarrhea and re-increase in toxin titer 10 d after treatment compared with that by vancomycin treatment. In in vitro experiments, teicoplanin exhibited time-dependent antibacterial activity and possessed lower MIC and longer post-antibiotic effect than vancomycin against C. difficile. C. difficile toxin production was numerically lower with teicoplanin exposure than with vancomycin exposure.

CONCLUSIONS

The results obtained from the present basic experiments could suggest that teicoplanin is a potential antibiotic for the treatment of severe CDI with recurrence-prevention activity.

Clinical Efficacy of Fidaxomicin and Oral Metronidazole for Treating Clostridioides difficile Infection and the Associated Recurrence Rate: A Retrospective Cohort Study

Clostridioides difficile infection (CDI) has significant implications for healthcare economics. Although clinical trials have compared fidaxomicin (FDX) and vancomycin, comparisons of FDX and oral metronidazole (MNZ) are limited. Therefore, we compared the therapeutic effects of FDX and oral MNZ. Patients diagnosed with CDI between January 2015 and March 2023 were enrolled. Those treated with oral MNZ or FDX were selected and retrospectively analyzed. The primary outcome was the global cure rate. Secondary outcomes included factors contributing to the CDI global cure rate; the rate of medication change owing to initial treatment failure; and incidence rates of clinical cure, recurrence, and all-cause mortality within 30 days. Of the 264 enrolled patients, 75 and 30 received initial oral MNZ and FDX treatments, respectively. The corresponding CDI global cure rates were 53.3% and 70% (p = 0.12). In multivariate analysis, FDX was not associated with the global cure rate. In the MNZ group, 18.7% of the patients had to change medications owing to initial treatment failure. The FDX group had a higher clinical cure rate and lower recurrence rate than the MNZ group, although not significant. However, caution is necessary owing to necessary treatment changes due to MNZ failure.

Decoding a cryptic mechanism of metronidazole resistance among globally disseminated fluoroquinolone-resistant Clostridioides difficile

Severe outbreaks and deaths have been linked to the emergence and global spread of fluoroquinolone-resistant Clostridioides difficile over the past two decades. At the same time, metronidazole, a nitro-containing antibiotic, has shown decreasing clinical efficacy in treating C. difficile infection (CDI). Most metronidazole-resistant C. difficile exhibit an unusual resistance phenotype that can only be detected in susceptibility tests using molecularly intact heme. Here, we describe the mechanism underlying this trait. We find that most metronidazole-resistant C. difficile strains carry a T-to-G mutation (which we term PnimB^G) in the promoter of gene nimB, resulting in constitutive transcription. Silencing or deleting nimB eliminates metronidazole resistance. NimB is related to Nim proteins that are known to confer resistance to nitroimidazoles. We show that NimB is a heme-dependent flavin enzyme that degrades nitroimidazoles to amines lacking antimicrobial activity. Furthermore, occurrence of the PnimB^G mutation is associated with a Thr82Ile substitution in DNA gyrase that confers fluoroquinolone resistance in epidemic strains. Our findings suggest that the pandemic of fluoroquinolone-resistant C. difficile occurring over the past few decades has also been characterized by widespread resistance to metronidazole.

Clostridioides difficile resistance to antibiotics, including post-COVID-19 data

INTRODUCTION

Updating data on Clostridioides difficile antibiotic resistance is important for treatment improvement of C. difficile infections (CDIs).

AREAS COVERED

Results from 20 countries were included. The mean resistance to 2 mg/l vancomycin, 2 mg/l metronidazole, 4 mg/l moxifloxacin, and 4 mg/l clindamycin was 4.7% (0 to ≥ 26% in two studies), 2.6% (0 to ≥ 40% in 3 studies), 34.9% (6.6->80%), and 61.0% (30->90%), respectively. Resistance to erythromycin (>60-88%), rifampin (>23-55.0%), imipenem (0.6 to > 78% in a clone), tigecycline (0-<5.0%), and fidaxomicin (0-2%) was also found. Resistance to ≥ 5 antibiotics of different classes was reported in some countries. High resistance and multidrug resistance were observed in hypervirulent and epidemic strains. Although only 1% of COVID-19 patients had CDIs, the proportion might be underestimated.

EXPERT OPINION

C. difficile antimicrobial susceptibility varied by country/region, study period, and circulating ribotypes. For CDI treatment, fidaxomicin (preferably) or vancomycin is recommended, while metronidazole is suitable for mild infections. New approaches, including biotherapeutics (Rebyota), strains, antibiotics (ridinilazole and ibezapolstat), and monoclonal antibodies/cocktails merit further evaluation. Because of the resistance rate variations, C. difficile antibiotic susceptibility should be regularly monitored. Post-COVID-19 resistance should be separately presented. Some discrepancies between vancomycin and metronidazole results need to be clarified.

Antimicrobial Efficacy Evaluations of Metronidazole against Clostridioides difficile Infection using Fecal Pharmacokinetic and Pharmacodynamic Analyses

OBJECTIVES

The pharmacokinetics/pharmacodynamics (PK/PD) characteristics of metronidazole (MNZ) in Clostridioides difficile infection (CDI) remain unclear. We aimed to determine the PK/PD characteristics of MNZ using a fecal PK/PD analysis model.

METHODS

Susceptibility testing, time-kill studies, and post-antibiotic effect (PAE) measurements were performed to evaluate in vitro PD profiles. MNZ was subcutaneously administered to mice infected with C. difficile ATCC® 43255 to evaluate in vivo PK and PD profiles, followed by determining fecal PK/PD indices with target value.

RESULTS

MNZ exerted concentration-dependent bactericidal activities with minimum inhibitory concentration (MIC) and PAE being 0.79 µg/mL and 4.8 h, respectively, against C. difficile ATCC® 43255. The reduction in vegetative cells in feces and treatment outcomes were most closely correlated with the ratio of the area under the fecal drug concentration-time curve from 0 to 24 h to the MIC (fecal AUC24/MIC). The target value of fecal AUC24/MIC to achieve a 1 log10 reduction in vegetative cells was 188. Upon meeting the target value, high survival rates (94.5%) and low clinical sickness score grading (5.2) were achieved in the CDI mouse models.

CONCLUSIONS

The PK/PD index and its target value of MNZ for CDI treatment was fecal AUC24/MIC ≥ 188. These findings may contribute to the effective clinical use of MNZ.

Optimal therapeutic recommendation for Clostridioides difficile infection in pediatric and adolescent populations: a systematic review and meta-analysis

We conducted a systematic review and meta-analysis to examine the efficacy profiles of metronidazole (MNZ) and vancomycin (VCM) in pediatric and adolescent patients with Clostridioides difficile infection (CDI). A systematic review and meta-analysis was conducted using four electronic databases (PubMed, Cochrane Library, Web of Science, and Clinicaltrials.gov) through July 6, 2022. We analyzed the clinical cure and recurrence rates to determine the efficacy of MNZ and VCM. The clinical cure rates in all included studies were not significantly different between MNZ and VCM (OR = 0.63; 95% CI = 0.36-1.10; I² = 0%; P = 0.10). Subgroup analyses were performed separately for each region to account for regional differences in the CDI. MNZ treatment achieved significantly lower clinical cure rates than did VCM in the United States of America (USA) and Europe (OR = 0.42, 95% CI = 0.19-0.93, I² = 0%, P = 0.03). Recurrence rates were not significantly different between MNZ and VCM (OR = 1.48, 95% CI = 0.62-3.53, I² = 28%, P = 0.38).    Conclusion: MNZ exhibited significantly lower clinical cure rates than did VCM in the US and Europe; therefore, it is not recommended for the management of CDI in pediatric and adolescent populations. What is Known: • The unavailability of robust data on recommendations of therapeutic agents for the management of Clostridioides difficile infections in children precludes effective antibiotic choice. What is New: • Metronidazole exhibited significantly lower clinical cure rates than did vancomycin in the United States of America and Europe and recurrence rate was not significantly different between metronidazole and vancomycin; therefore, it is not recommended for the management of Clostridioides difficile infection in children.

Impact of Nucleic Acid Amplification Test on Clinical Outcomes in Patients with Clostridioides difficile Infection

A nucleic acid amplification test (NAAT) is recommended to determine whether or not patients have a Clostridioides difficile infection (CDI) when the glutamate dehydrogenase activity assay is positive and the rapid membrane enzyme immunoassays for toxins is negative. In our hospital, a NAAT was introduced to diagnose CDI precisely in April 2020. This study aimed to investigate the impact of a NAAT on the clinical outcomes in patients with CDI at our hospital. Seventy-one patients diagnosed with CDI between April 2017 and March 2022 were included in our study. Patients with CDI were divided into two groups: before (pre-NAAT) and after (post-NAAT) the introduction of NAAT. The clinical outcome was compared between the two groups. Of the 71 patients with CDI, 41 were sorted into the pre-NAAT group and 30 into the post-NAAT group. The clinical cure rate was significantly higher in the post-NAAT group compared to the pre-NAAT group (76.7% vs. 48.8%, p = 0.018). In the multivariable analysis, the clinical cure was significantly associated with the introduction of NAAT (p = 0.022). Our findings suggest that the introduction of NAAT can improve the clinical outcomes in CDI patients.

Deprescribing antacids after the diagnosis of Clostridioides difficile infection: A single-center observational study

Overuse of antacids is associated with the development and recurrence of Clostridioides difficile infection (CDI). Discontinuation of unnecessary antacids for CDI management is advocated; however, the clinical pervasiveness on the discontinuation of antacids remains unclear. We conducted a single-center retrospective observational study to determine the rate of antacid discontinuation following CDI diagnosis. Among 51 patients (58 infections; median age 76.5 years, range 69-82; 53.5% women) treated with antimicrobials against C. difficile, 41 had been treated with antacids, and of these, 18 exhibited no indication for antacid administration. However, none had discontinued antacid use. While CDI provides an opportunity for antacid stewardship, it is not implemented in clinical practice. In addition to the efforts of individual clinicians, the dissemination of knowledge of the indications and side effects of antacids, establishment of a multidisciplinary support system, and creation and implementation of a clinical stewardship pathway are necessary to increase the deprescription of antacids in patients with CDI.