Clostridium difficile: Changing Epidemiology, Treatment and Infection Prevention Measures

Phenotypical and Genotypical Comparison of Clostridium difficile Isolated from Clinical Samples: Homebrew DNA Fingerprinting versus Antibiotic Susceptibility Testing (AST) and Clostridial Toxin Genes

Background

Clostridium (Clostridioides) difficile is recognized as the major cause of healthcare antibiotic-associated diarrhea. We surveyed a molecular epidemiological correlation between the clinical isolates from two general hospitals in Iran through clustering toxigenic types and antibiotic susceptibility testing (AST) accuracy.

Methods

Study population included 460 diarrhoeic specimens from inpatients with a history of antibiotic therapy. All samples underwent enriched anaerobic culture, confirmed by detection of gluD gene with PCR. Toxin status and AST were assessed by the disk diffusion method (DDM) and minimal inhibitory concentrations (MICs) of metronidazole, vancomycin, and rifampin. C. difficile outbreak was analyzed through conventional PCR by tracing toxin genes and Homebrew pulsed-field gel electrophoresis (PFGE) for characterizing isolates within our healthcare systems.

Results

A total of 29 C. difficile strains were isolated by enriched anaerobic culture from the clinical samples. Among them, 22 (4.8%) toxigenic profiles yielded toxins A and B (tcdA, tcdB) and binary toxins (cdtA, cdtB). The minimum inhibitory concentration (MIC) was 18.1% and 9% for vancomycin and metronidazole, and all isolates were susceptible to rifampicin and its minimum inhibitory concentration was at <0.003 μg/mL. The most dominant toxigenic and antibiotic-resistant “pulsotype F” was detected through PFGE combined with multiple Clostridial toxigenic pattern and AST.

Conclusions

DNA fingerprinting studies represent a powerful tool in surveying hypervirulent C. difficile strains in clinical settings. Resistance to vancomycin and metronidazole, as first-line antibiotics, necessitate accomplishment of proper control strategies and also prescription of tigecycline as a more appropriate option.

Educational antimicrobial stewardship programs in medical schools: a scoping review protocol

OBJECTIVE

The objective of this scoping review is to identify the available evidence on antimicrobial stewardship programs for teaching medical students about rational antimicrobial use, including the content taught and the method of instruction used.

INTRODUCTION

Antibiotics are life-saving drugs and their discovery is one of the most important advances of the 20th century. They have transformed modern medicine by playing a critical role in the management of infectious diseases. However, the rapid development of resistance of pathogens to antibiotics is gradually affecting this initial success. Antimicrobial stewardship programs have been shown to reduce the burden of antimicrobial resistance in hospitals.

INCLUSION CRITERIA

This scoping review will consider papers conducted in medical school curricula to improve the prescribing of antimicrobial medication. Studies that include other health profession students, such as nursing, pharmacy, or dentistry students, will be excluded. Studies published in English from 1996 onwards will be included.

METHODS

Databases to be searched are PubMed, Wiley Online library, CINAHL Complete, Web of Knowledge, Scopus and Education Resources Information Center. Unpublished studies and gray literature will be included. Searching will follow a three-step process and will be conducted by two reviewers. Data will be extracted by two independent reviewers. Any disagreements that arise between the reviewers during the study selection process or data extraction will be resolved through discussion, or with a third reviewer. Results will be presented in tabular or diagrammatic form, together with a narrative summary.

Effectiveness of probiotics in reducing the incidence of Clostridium difficile-associated diarrhea in elderly patients: a systematic review

BACKGROUND

Clostridium difficile bacteria are a leading cause of infectious diarrhea. This is an anaerobic, gram-positive and spore-forming rod responsible for significant morbidity and mortality, especially among elderly hospitalized patients. Standard management of C. difficile-associated diarrhea (CDAD) consists of discontinuing a causative antibiotic, correcting fluid-electrolytes imbalance and initiating an antibiotic treatment for CDAD. Alternative approaches for prevention of CDAD include probiotics. This systematic review will provide a comprehensive, unbiased summary of the available research on the effectiveness of probiotics in decreasing the incidence of infectious diarrhea in elderly hospitalized patients.

OBJECTIVES

To conduct a systematic review to determine the best available evidence related to the effectiveness of probiotics in the prevention of CDAD in elderly hospitalized patients. The review question was: are probiotics effective in decreasing the incidence of CDAD in elderly hospitalized patients?

INCLUSION CRITERIA TYPES OF PARTICIPANTS

The current review included studies of participants who were aged 60 years and more and who were residents of acute- and post-acute care facilities undergoing or planning to undergo antibiotic treatment for the management of any infectious conditions, except CDAD.

TYPES OF INTERVENTION(S)

The current review included studies that evaluated the effectiveness of probiotics for prevention of CDAD in elderly hospitalized patients in acute- and post-acute care settings compared to usual care.

OUTCOMES

The current review included studies examining the following outcome measures: incidence or relapse of CDAD. Cases of CDAD were defined by presence of diarrhea and verified by positive results for stool enzyme immunoassay for toxins A and B.

TYPES OF STUDIES

The current review included only experimental study designs including randomized controlled trials.

SEARCH STRATEGY

The search strategy included studies published in English between 1978, when the first case of CDAD was reported, and 2015.

ASSESSMENT OF METHODOLOGICAL QUALITY

Papers selected for retrieval were assessed by two independent reviewers for methodological quality prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute (JBI).

DATA EXTRACTION

Data were extracted from papers included in the review using the standardized data extraction tool from the JBI Meta-Analysis of Statistics Assessment and Review Instrument. The data extracted included specific details about the interventions, populations, study methods and outcomes of significance to the review question and specific objectives.

DATA SYNTHESIS

Quantitative data were pooled using statistical meta-analysis. Effect sizes were expressed as odds ratios, and their 95% confidence intervals were calculated to determine if probiotic treatment was superior to placebo in reducing CDAD incidence. Heterogeneity was assessed using the standard I statistic.

RESULTS

Five studies were included in the review. The individual study results were conflicting, including non-significant results for four studies and statistically significant results in one that demonstrated fewer cases of CDAD among patients receiving probiotics compared to placebo. The meta-analysis finding indicated that there was no statistically significant difference in CDAD incidence in elderly hospitalized patients taking probiotics when compared to a placebo.

CONCLUSION

Probiotics were not found to be more effective than placebo for reducing CDAD incidence in elderly hospitalized patients. However, studies that demonstrate improved outcomes must be examined to determine future needs for research. Studies varied with regard to the dose, frequency, method of administration (probiotic drinks versus capsule), length of administration and the number of strains of bacteria administered. Further studies are needed to evaluate the effectiveness of probiotics for CDAD prevention in this population. Clinical trials with evidence-based administration methods and meta-analyses that pool the results of studies with congruent methodologies are needed to enable conclusions to be drawn on the effectiveness of probiotic administration for CDAD prevention.

Decreasing Clostridium difficile-Associated Fatality Rates Among Hospitalized Patients in the United States: 2004-2014

BACKGROUND

Clostridium difficile infection has emerged as a major public health problem in the United States over the last 2 decades. We examined the trends in the C. difficile-associated fatality rate, hospital length of stay, and hospital charges over the last decade.

METHODS

We used data from the National Inpatient Sample to identify patients with a principal diagnosis of C. difficile infection from 2004 to 2014. Outcomes included in-hospital fatality rate, hospital length of stay, and hospital charges. For each outcome, trends were also stratified by age categories because the risk of infection and associated mortality increases with age.

RESULTS

Clostridium difficile infection discharges increased from 19.9 per 100,000 persons in 2004 to 33.8 per 100,000 persons in 2014. Clostridium difficile-associated fatality decreased from 3.6% in 2004 to 1.6% in 2014 (P < .001). Among patients aged 45-64 years, fatality decreased from 1.2% in 2004 to 0.7% in 2014 (P < .001). Among patients aged 65-84 years, fatality decreased from 4.3% in 2004 to 2.0% in 2014 (P < .001). Among patients aged ≥85 years, fatality decreased from 6.9% in 2004 to 3.6% in 2014 (P < .001). The mean length of hospital stay decreased from 6.9 days in 2004 to 5.8 days in 2014 (P < .001). The mean hospital charges increased from 2004 ($24,535) to 2014 ($35,898) (P < .001).

CONCLUSION

In-hospital fatality associated with C. difficile infection in the United States has decreased more than 2-fold in the last decade, despite increasing infection rates.

Identification of Highly Specific Diversity-Oriented Synthesis-Derived Inhibitors of Clostridium difficile

In 2013, the Centers for Disease Control highlighted Clostridium difficile as an urgent threat for antibiotic-resistant infections, in part due to the emergence of highly virulent fluoroquinolone-resistant strains. Limited therapeutic options currently exist, many of which result in disease relapse. We sought to identify molecules specifically targeting C. difficile in high-throughput screens of our diversity-oriented synthesis compound collection. We identified two scaffolds with apparently novel mechanisms of action that selectively target C. difficile while having little to no activity against other intestinal anaerobes; preliminary evidence suggests that compounds from one of these scaffolds target the glutamate racemase. In vivo efficacy data suggest that both compound series may provide lead optimization candidates.

Advances in the Microbiome: Applications to Clostridium difficile Infection

Clostridium difficile is a major cause of morbidity and mortality worldwide, causing over 400,000 infections and approximately 29,000 deaths in the United States alone each year. C. difficile is the most common cause of nosocomial diarrhoea in the developed world, and, in recent years, the emergence of hyper-virulent (mainly ribotypes 027 and 078, sometimes characterised by increased toxin production), epidemic strains and an increase in the number of community-acquired infections has caused further concern. Antibiotic therapy with metronidazole, vancomycin or fidaxomicin is the primary treatment for C. difficile infection (CDI). However, CDI is unique, in that, antibiotic use is also a major risk factor for acquiring CDI or recurrent CDI due to disruption of the normal gut microbiota. Therefore, there is an urgent need for alternative, non-antibiotic therapeutics to treat or prevent CDI. Here, we review a number of such potential treatments which have emerged from advances in the field of microbiome research.

Molecular Epidemiology of Clostridium difficile Infection in a Large Teaching Hospital in Thailand

Clostridium difficile infection (CDI) is a leading cause of healthcare-associated morbidity and mortality worldwide. In Thailand, CDI exhibits low recurrence and mortality and its molecular epidemiology is unknown. CDI surveillance was conducted in a tertiary facility (Siriraj Hospital, Bangkok). A total of 53 toxigenic C. difficile strains from Thai patients were analyzed by multi-locus sequence typing (MLST), PCR ribotyping, and pulse-field gel electrophoresis (PFGE). The mean age of the cohort was 64 years and 62.3% were female; 37.7% of patients were exposed to > two antibiotics prior to a diagnosis of CDI, with beta-lactams the most commonly used drug (56.3%). Metronidazole was used most commonly (77.5%; success rate 83.9%), and non-responders were treated with vancomycin (success rate 100%). None of the isolates carried binary toxin genes. Most isolates (98.2–100%) were susceptible to metronidazole, vancomycin, tigecycline and daptomycin. There were 11 sequence types (STs), 13 ribotypes (RTs) and four PFGE types. Six previously identified STs (ST12, ST13, ST14, ST33, ST41 and ST45) and five novel STs unique to Thailand (ST66, ST67, ST68, ST69 and ST70) were identified. PCR RTs UK 017 (ST45) (45.3%) and UK 014/020 (ST33) (24.5%) were the most common. High concordance was observed between the MLST and ribotyping results (p<0.001). C. difficile isolates from Thai patients were highly susceptible to standard antimicrobial agents. In conclusion, the five STs indicate the high genetic diversity and unique polymorphisms in Thailand. Moreover, the emergence of antimicrobial resistance to vancomycin warranted continuous surveillance to prevent further spread of the toxigenic C. difficile isolates.

Clostridium difficile in Crete, Greece: epidemiology, microbiology and clinical disease

We studied the epidemiology and microbiology of Clostridium difficile and the characteristics of patients with C. difficile infection (CDI) in Crete in three groups of hospitalized patients with diarrhoea: group 1 [positive culture and positive toxin by enzyme immunoassay (EIA)]; group 2 (positive culture, negative toxin); group 3 (negative culture, negative toxin). Patients in group 1 were designated as those with definitive CDI (20 patients for whom data was available) and matched with cases in group 2 (40 patients) and group 3 (40 patients). C. difficile grew from 6% (263/4379) of stool specimens; 14·4% of these had positive EIA, of which 3% were resistant to metronidazole. Three isolates had decreased vancomycin susceptibility. Patients in groups 1 and 2 received more antibiotics (P = 0·03) and had more infectious episodes (P = 0·03) than patients in group 3 prior to diarrhoea. Antibiotic administration for C. difficile did not differ between groups 1 and 2. Mortality was similar in all three groups (10%, 12·5% and 5%, P = 0·49). CDI frequency was low in the University Hospital of Crete and isolates were susceptible to metronidazole and vancomycin.

Faecal microbiota transplantation and bacteriotherapy for recurrent Clostridium difficile infection: a retrospective evaluation of 31 patients

BACKGROUND

Recurrent Clostridium difficile infection (CDI) is a significant problem due to its increased incidence and severity. Failure rates for standard antibiotic therapies are high. In our hospital, faecal microbiota transplantation (FMT), or instillation of a culture mixture of known enteric bacteria in saline as rectal bacteriotherapy (RBT), has long been used as 'rescue therapy' in patients with recurrent disease, in whom repeated courses of standard antibiotic treatment have failed. We wanted to evaluate the effectiveness of FMT and RBT for recurrent CDI.

METHODS

The records of 31 patients treated with either FMT or RBT for recurrent CDI were reviewed retrospectively. FMT was based on faecal donation by a close relative and RBT on a defined saline mixture of 10 individually cultured enteric bacterial strains originally isolated from healthy persons. Both types of instillation were carried out through a rectal catheter. FMT (500 ml) was given as 1 installation. RBT (200 ml) was given as 2 or 3 installations with an interval of 2 days between courses. Treatment success was defined as a sustained loss of symptoms and discontinuation of diarrhoea within 3 days.

RESULTS

Of 31 patients, 23 (74%) responded successfully to the treatment: 16 of 23 (70%) receiving FMT and 7 of 8 (88%) receiving RBT.

CONCLUSION

We found FMT to be effective in patients with recurrent CDI. RBT based on a predefined bacterial suspension was as effective as or better than FMT based on faecal donation; however, multiple installations may be needed.

Current status of surgical treatment for fulminant clostridium difficile colitis

Mortality rates attributable to fulminant Clostridium difficile (C. difficile) colitis remain high and are reported to be 38%-80%. Historically, the threshold for surgical intervention has been judged empirically because level I evidence to guide decision making is lacking. Studies of the surgical management of C. difficile infection have been limited by small sample size and the lack of a standard definition of fulminancy. Multiple small and medium-sized series have examined the surgical management of C. difficile. However, because of a lack of prospective, randomized studies, it has been difficult to identify the optimal point for surgical intervention in patients with severe fulminant C. difficile colitis. Our goal was to analyze the existing body of literature in an attempt to define host constellations, which would predict the development of the more aggressive form of this disease and hence justify an early or earlier surgical intervention. A Pubmed search was conducted using the keywords “fulminant”, “clostridium difficile”, “surgery”, and “colitis”. Reviews and meta-analyses proposing indications for surgical consultation or operative management in patients with C. difficile colitis were included. After analyzing current literature, we identified a number of parameters that are associated with unfavorable outcomes. The parameters include age greater than 65 years old, peritoneal signs on physical examination, abdominal distension, signs of end-organ failure, hypotension less than 90 mmHg systolic blood pressure, tachycardia greater than 100 bpm, vasopressor requirement, elevated WBC count of greater than at least

16 × 10⁹/μL, serum lactate of greater than 2.2 mmol/L, and lastly, radiologic findings suggestive of pancolitis, ascites, megacolon, or colonic perforation. Even though fairly strong evidence exists in contemporary literature, we recommend use of these identified parameters with caution in clinical practice when it comes to the actual decision to treat certain patients more aggressively. The identified risk factors should be used to lower surgeons’ threshold for operative treatment early in the course of the disease.