Comparison of treatment outcomes with vancomycin alone versus combination therapy in severe Clostridium difficile infection

Efficacy Assessment of the Co-Administration of Vancomycin and Metronidazole in Clostridioides difficile-Infected Mice Based on Changes in Intestinal Ecology

Vancomycin (VAN) and metronidazole (MTR) remain the current drugs of choice for the treatment of non-severe Clostridioides difficile infection (CDI); however, while their co-administration has appeared in clinical treatment, the efficacy varies greatly and the mechanism is unknown. In this study, a CDI mouse model was constructed to evaluate the therapeutic effects of VAN and MTR alone or in combination. For a perspective on the intestinal ecology, 16S rRNA amplicon sequencing and non-targeted metabolomics techniques were used to investigate changes in the fecal microbiota and metabolome of mice under the co-administration treatment. As a result, the survival rate of mice under co-administration was not dramatically different compared to that of single antibiotics, and the former caused intestinal tissue hyperplasia and edema. Co-administration also significantly enhanced the activity of amino acid metabolic pathways represented by phenylalanine, arginine, proline, and histidine, decreased the level of deoxycholic acid (DCA), and downregulated the abundance of beneficial microbes, such as Bifidobacterium and Akkermansia. VAN plays a dominant role in microbiota regulation in co-administration. In addition, co-administration reduced or increased the relative abundance of antibiotic-sensitive bacteria, including beneficial and harmful microbes, without a difference. Taken together, there are some risks associated with the co-administration of VAN and MTR, and this combination mode should be used with caution in CDI treatment.

Risk factors for development of initial Clostridioides difficile infection

OBJECTIVES

The purpose of this study was to identify risk factors for initial complicated Clostridioides difficile infection (CDI).

METHODS

This retrospective cross-sectional study included adult patients with initial episodes of CDI who received ≥72 h of CDI-active antimicrobials. Patients were categorised into one of two groups: complicated CDI or uncomplicated CDI. A total of 513 patients were screened for inclusion, with complicated CDI patients exhibiting abnormal abdominal CT findings or experiencing death within 30 days post-CDI diagnosis.

RESULTS

A total of 203 patients met the inclusion criteria, comprising 143 (70.4%) with uncomplicated CDI and 60 (29.6%) with complicated CDI. Complicated CDI patients were more likely to have been exposed to fluoroquinolones (48.3% vs. 30.8%; P = 0.017) and to carbapenems for a longer duration prior to CDI diagnosis (7 days vs. 3 days; P = 0.019). They were more likely to receive oral vancomycin (65.0% vs. 46.9%; P = 0.018) and rectal vancomycin (5.0% vs. 0%; P = 0.025) compared with uncomplicated CDI patients. Logistic regression identified previous fluoroquinolone exposure increased the risk of complicated CDI, while previous abdominal surgery decreased the risk.

CONCLUSION

Almost one-third of included patients experienced a complicated episode of CDI as their initial episode. Further research is warranted to elucidate the extent of influence of prior antibiotics on the development of complicated CDI.

Oral Vancomycin Monotherapy Versus Combination Therapy in Solid Organ Transplant Recipients With Uncomplicated Clostridium difficile Infection: A Retrospective Cohort Study

INTRODUCTION

Solid organ transplant (SOT) recipients are at high risk of Clostridium difficile infection (CDI) and CDI recurrence due to their suppressed immune systems and antibiotic exposure. A combination of metronidazole and oral vancomycin is often prescribed for SOT recipients with uncomplicated CDI despite any clinical practice guidelines supporting the need for combination therapy. This study aims to compare the CDI recurrence rates of metronidazole/vancomycin combination therapy to oral vancomycin monotherapy in SOT recipients after a first episode of uncomplicated CDI.

METHODS

A single-center retrospective cohort study evaluated SOT recipients diagnosed with uncomplicated CDI who were treated with vancomycin monotherapy or vancomycin/metronidazole combination therapy. The primary endpoint was CDI recurrence defined as a second CDI episode within 8 weeks of completing index CDI therapy. The secondary endpoints were time between the end of CDI therapy and recurrence, length of total hospitalization after the index CDI, and length of hospitalization after index CDI diagnosis.

RESULTS

Fifteen patients (25%) of 61 subjects experienced CDI recurrence. There was no statistically significant difference in CDI recurrence rate between the vancomycin monotherapy group and combination therapy group (23% versus 27%, respectively; P = .715). The median total length of hospitalization between the vancomycin monotherapy and combination therapy groups was statistically significant (9 versus 14 days, respectively; P = .047).

DISCUSSION

There was no difference found in recurrence rate between oral vancomycin monotherapy versus combination therapy. The study result weakens the practice of prescribing combination therapy for uncomplicated CDI in SOT recipients.

The outcome of patients with severe and severe-complicated Clostridium difficile infection treated with tigecycline combination therapy: a retrospective observational study

BACKGROUND

Tigecycline is a third-line therapy for severe Clostridium difficile infection (CDI) in Australasian guidelines. Differences in strain types make it difficult to extrapolate international tigecycline efficacy data with combination or monotherapy to Australian practice, where experience is limited.

AIM

To evaluate the efficacy and adverse effects associated with tigecycline combination therapy for severe and severe-complicated CDI in an Australian healthcare setting.

METHODS

This was a retrospective observational study at a metropolitan university-affiliated hospital. All patients between February 2013 and October 2016 treated with adjunctive intravenous tigecycline for >48 h for severe or severe-complicated CDI were included. Tigecycline was given in addition to oral vancomycin ± intravenous metronidazole. The primary outcome was all-cause mortality at 30 days from start of tigecycline combination therapy. Secondary outcomes included clinical cure, colectomy, adverse events and recurrence rates.

RESULTS

Thirteen patients with median age of 61 years had severe (n = 9) or severe-complicated (n = 4) CDI at tigecycline commencement. In 92% of patients, tigecycline started within 48 h after in-hospital CDI treatment, for median duration of 9 days. All-cause mortality at 30 days was 8% with no mortality in severe CDI and 25% (1/4) in patients with severe-complicated fulminant CDI, comparing favourably with historical rates of 9-38% and 30-80% in similar respective groups. Clinical cure was achieved in 77% of cases. There were no colectomies and one attributable tigecycline adverse reaction.

CONCLUSIONS

Tigecycline appears safe and effective as a part of combination therapy in severe CDI, and may be given earlier and for shorter durations than in current guidelines.

Antibiotic Treatments for Clostridium difficile Infection Are Associated with Distinct Bacterial and Fungal Community Structures

Clostridium difficile infection (CDI) is the most common nosocomial infection in the United States, being associated with high recurrence and persistence rates. Though the relationship between intestinal dysbiosis and CDI is well known, it is unclear whether different forms of dysbiosis may potentially affect the course of CDI. How this is further influenced by C. difficile-directed antibiotics is virtually uninvestigated. In this study, diarrheal stool samples were collected from 20 hospitalized patients, half of whom were confirmed to have CDI. Analyzing tissue ex vivo and in duplicate, CDI and non-CDI fecal samples (n = 176) were either not antibiotic treated or treated with metronidazole, vancomycin, or fidaxomicin, the three most common CDI therapies. The microbial community composition, interactions, and predicted metabolic functions were assessed by 16S rRNA gene and internal transcribed spacer sequencing, bipartite network analysis, and phylogenetic investigation of communities by reconstruction of unobserved states. Our results demonstrate that while all C. difficile-directed antibiotics were associated with similar reductions in alpha diversity, beta diversity significantly differed on the basis of the particular antibiotic, with differentiating relative abundances of bacterial and fungal assemblages. With the exception of fidaxomicin, each antibiotic was associated with the emergence of potentially pathogenic fungal operational taxonomic units, with predicted bacterial functions enriched for xenobiotic metabolism that could perpetuate the dysbiosis driving CDI. Toxin-independent mechanisms of colitis related to the relative abundance of pathogenic bacteria and fungi were also noted. This study suggests that a transkingdom interaction between fungi and bacteria may be important in CDI pathophysiology, including being a factor in the historically high persistence and recurrence rates associated with this disease. IMPORTANCE Using human fecal samples and including sequencing for both bacterial and fungal taxa, this study compared the conventional antibiotics used to treat C. difficile infection (CDI) from the perspective of the microbiome, which is particularly relevant, given the relationship between dysbiotic states and the development of CDI. Sequencing and imputed functional analyses suggest that C. difficile-directed antibiotics are associated with distinct forms of dysbiosis that may be influential in the course of CDI. Further, a role for fungal organisms in the perpetuation of the causal dysbiosis of CDI is discussed, suggesting a previously unappreciated, clinically relevant transkingdom interaction that warrants further study.

Lack of Benefit With Combination Therapy for Clostridium difficile Infection

Limited data exist regarding combination therapy for Clostridium difficile infection (CDI). After adjusting for confounders in a cohort of patients with CDI and≥1 year old, combination therapy was not associated with significant differences in clinical outcomes, but it was associated with prolonged duration of therapy (1.22 days; 95% confidence interval, 1.03-1.44 days; P=.02). Infect Control Hosp Epidemiol 2017;38:602-605.

Australasian Society of Infectious Diseases updated guidelines for the management of Clostridium difficile infection in adults and children in Australia and New Zealand

The incidence of Clostridium difficile infection (CDI) continues to rise, whilst treatment remains problematic due to recurrent, refractory and potentially severe nature of disease. The treatment of C. difficile is a challenge for community and hospital-based clinicians. With the advent of an expanding therapeutic arsenal against C. difficile since the last published Australasian guidelines, an update on CDI treatment recommendations for Australasian clinicians was required. On behalf of the Australasian Society of Infectious Diseases, we present the updated guidelines for the management of CDI in adults and children.

Efficacy and Safety of Metronidazole Monotherapy versus Vancomycin Monotherapy or Combination Therapy in Patients with Clostridium difficile Infection: A Systematic Review and Meta-Analysis

Background

Clostridium difficile infection (CDI) has become a global epidemiological problem for both hospitalized patients and outpatients. The most commonly used drugs to treat CDI are metronidazole and vancomycin. The aim of this study was to compare the efficacy and safety of metronidazole monotherapy with vancomycin monotherapy and combination therapy in CDI patients.

Methods

A comprehensive search without publication status or other restrictions was conducted. Studies comparing metronidazole monotherapy with vancomycin monotherapy or combination therapy in patients with CDI were considered eligible. Meta-analysis was performed using the Mantel-Haenszel fixed-effects model, and odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated and reported.

Results

Of the 1910 records identified, seventeen studies from thirteen articles (n = 2501 patients) were included. No statistically significant difference in the rate of clinical cure was found between metronidazole and vancomycin for mild CDI (OR = 0.67, 95% CI (0.45, 1.00), p = 0.05) or between either monotherapy and combination therapy for CDI (OR = 1.07, 95% CI (0.58, 1.96), p = 0.83); however, the rate of clinical cure was lower for metronidazole than for vancomycin for severe CDI (OR = 0.46, 95% CI (0.26, 0.80), p = 0.006). No statistically significant difference in the rate of CDI recurrence was found between metronidazole and vancomycin for mild CDI (OR = 0.99, 95% CI (0.40, 2.45), p = 0.98) or severe CDI (OR = 0.98, 95% CI (0.63, 1.53), p = 0.94) or between either monotherapy and combination therapy for CDI (OR = 0.91, 95% CI (0.66, 1.26), p = 0.56). In addition, there was no significant difference in the rate of adverse events (AEs) between metronidazole and vancomycin (OR = 1.18, 95% CI (0.80, 1.74), p = 0.41). In contrast, the rate of AEs was significantly lower for either monotherapy than for combination therapy (OR = 0.30, 95% CI (0.17, 0.51), p<0.0001).

Conclusions

Metronidazole and vancomycin are equally effective for the treatment of mild CDI, but vancomycin is superior for the treatment of severe CDI. Combination therapy is not superior to monotherapy because it appears to be associated with an increase in the rate of AEs.

Challenges and opportunities in the management of Clostridium difficile infection

Clostridium difficile infection (CDI) is increasing in all regions of the world where sought. There is no gold standard for diagnosis of CDI, with available tests having limitations. Prevention of CDI will be seen with antibiotic stewardship, improved disinfection of hospitals and nursing homes, chemo- and immuno-prophylaxis and next generation probiotics. The important therapeutic agents are oral vancomycin and fidaxomicin with metronidazole being used only in mild cases or when oral therapy cannot be given. Current therapy of CDI for 10 days is associated with high rate of recurrence that may be prevented by prolonging initial therapy. Future treatment strategies will focus on drugs that inhibit C. difficile, reduce toxin activity and inflammation in the gut, and improve colonic flora diversity.