Is tigecycline a suitable option for Clostridium difficile infection? Evidence from the literature

Clostridioides difficile infection: history, epidemiology, risk factors, prevention, clinical manifestations, treatment, and future options

SUMMARYClostridioides difficile infection (CDI) is one of the major issues in nosocomial infections. This bacterium is constantly evolving and poses complex challenges for clinicians, often encountered in real-life scenarios. In the face of CDI, we are increasingly equipped with new therapeutic strategies, such as monoclonal antibodies and live biotherapeutic products, which need to be thoroughly understood to fully harness their benefits. Moreover, interesting options are currently under study for the future, including bacteriophages, vaccines, and antibiotic inhibitors. Surveillance and prevention strategies continue to play a pivotal role in limiting the spread of the infection. In this review, we aim to provide the reader with a comprehensive overview of epidemiological aspects, predisposing factors, clinical manifestations, diagnostic tools, and current and future prophylactic and therapeutic options for C. difficile infection.

South African Society of Clinical Microbiology Clostridioides difficile infection diagnosis, management and infection prevention and control guideline

Clostridioides difficile infection (CDI) is a problem in both developed and developing countries and is a common hospital-acquired infection. This guideline provides evidence-based practical recommendations for South Africa and other developing countries. The scope of the guideline includes CDI diagnostic approaches; adult, paediatric and special populations treatment options; and surveillance and infection prevention and control recommendations.

Clostridioides difficile: diagnosis and treatments

Clostridioides difficile (formerly Clostridium) is a major cause of healthcare associated diarrhea, and is increasingly present in the community. Historically, C difficile infection was considered easy to diagnose and treat. Over the past two decades, however, diagnostic techniques have changed in line with a greater understanding of the physiopathology of C difficile infection and the use of new therapeutic molecules. The evolution of diagnosis showed there was an important under- and misdiagnosis of C difficile infection, emphasizing the importance of algorithms recommended by European and North American infectious diseases societies to obtain a reliable diagnosis. Previously, metronidazole was considered the reference drug to treat C difficile infection, but more recently vancomycin and other newer drugs are shown to have higher cure rates. Recurrence of infection represents a key parameter in the evaluation of new drugs, and the challenge is to target the right population with the adapted therapeutic molecule. In multiple recurrences, fecal microbiota transplantation is recommended. New approaches, including antibodies, vaccines, and new molecules are already available or in the pipeline, but more data are needed to support the inclusion of these in practice guidelines. This review aims to provide a baseline for clinicians to understand and stratify their choice in the diagnosis and treatment of C difficile infection based on the most recent data available.

New and emerging therapies in treatment of Clostridium difficile infection

Clostridium difficile infection (CDI) represents one of the most serious nosocomial infections that have grown dramatically over the past decade. Vancomycin and metronidazole are currently used as a standard therapy for CDI. Metronidazole is recommended as a first-line therapy for mild-to-moderate infections and vancomycin is mainly used for severe and/or refractory cases. However, studies have demonstrated that there are quite high CDI relapse rates with both of these medications, which represents a challenge for clinicians. Over the last decade, a number of newer and novel therapeutic options have emerged as promising alternatives to these standard CDI therapies. The following review provides the updated summaries of these newer therapeutic agents and their status in the treatment of CDI.

Novel Antimicrobials for the Treatment of Clostridium difficile Infection

The current picture of Clostridium difficile infection (CDI) is alarming with a mortality rate ranging between 3% and 15% and a CDI recurrence rate ranging from 12% to 40%. Despite the great efforts made over the past 10 years to face the CDI burden, there are still gray areas in our knowledge on CDI management. The traditional anti-CDI antimicrobials are not always adequate in addressing the current needs in CDI management. The aim of our review is to give an update on novel antimicrobials for the treatment of CDI, considering the currently available evidences on their efficacy, safety, molecular mechanism of action, and their probability to be successfully introduced into the clinical practice in the near future. We identified, through a PubMed search, 16 novel antimicrobial molecules under study for CDI treatment: cadazolid, surotomycin, ridinilazole, LFF571, ramoplanin, CRS3123, fusidic acid, nitazoxanide, rifampin, rifaximin, tigecycline, auranofin, NVB302, thuricin CD, lacticin 3147, and acyldepsipeptide antimicrobials. In comparison with the traditional anti-CDI antimicrobial treatment, some of the novel antimicrobials reviewed in this study offer several advantages, i.e., the favorable pharmacokinetic and pharmacodynamic profile, the narrow-spectrum activity against CD that implicates a low impact on the gut microbiota composition, the inhibitory activity on CD sporulation and toxins production. Among these novel antimicrobials, the most active compounds in reducing spore production are cadazolid, ridinilazole, CRS3123, ramoplanin and, potentially, the acyldepsipeptide antimicrobials. These antimicrobials may potentially reduce CD environment spread and persistence, thus reducing CDI healthcare-associated acquisition. However, some of them, i.e., surotomycin, fusidic acid, etc., will not be available due to lack of superiority versus standard of treatment. The most CD narrow-spectrum novel antimicrobials that allow to preserve microbiota integrity are cadazolid, ridinilazole, auranofin, and thuricin CD. In conclusion, the novel antimicrobial molecules under development for CDI have promising key features and advancements in comparison to the traditional anti-CDI antimicrobials. In the near future, some of these new molecules might be effective alternatives to fight CDI.

Sleeping with the enemy: Clostridium difficile infection in the intensive care unit

Over the last years, there was an increase in the number and severity of Clostridium difficile infections (CDI) in all medical settings, including the intensive care unit (ICU). The current prevalence of CDI among ICU patients is estimated at 0.4–4% and has severe impact on morbidity and mortality. An estimated 10–20% of patients are colonized with C. difficile without showing signs of infection and spores can be found throughout ICUs. It is not yet possible to predict whether and when colonization will become infection. Figuratively speaking, our patients are sleeping with the enemy and we do not know when this enemy awakens.

Most patients developing CDI in the ICU show a mild to moderate disease course. Nevertheless, difficult-to-treat severe and complicated cases also occur. Treatment failure is particularly frequent in ICU patients due to comorbidities and the necessity of continued antibiotic treatment. This review will give an overview of current diagnostic, therapeutic, and prophylactic challenges and options with a special focus on the ICU patient.

First, we focus on diagnosis and prognosis of disease severity. This includes inconsistencies in the definition of disease severity as well as diagnostic problems. Proceeding from there, we discuss that while at first glance the choice of first-line treatment for CDI in the ICU is a simple matter guided by international guidelines, there are a number of specific problems and inconsistencies. We cover treatment in severe CDI, the problem of early recognition of treatment failure, and possible concepts of intensifying treatment. In conclusion, we mention methods for CDI prevention in the ICU.

[Clostridium difficile infection : What is currently available for treatment?]

Clostridium difficile (C. difficile) is an anaerobic, Gram-positive, spore-forming, toxin-secreting bacillus. It is transmitted via a fecal-oral route and can be found in 1-3 % of the healthy population. Symptoms caused by C. difficile range from uncomplicated diarrhea to a toxic megacolon. The incidence, frequency of recurrence, and mortality rate of C. difficile infections (CDIs) have increased significantly over the past few decades. The most important risk factor is antibiotic treatment in elderly patients and patients with severe comorbidities. There is a screening test available to detect C. difficile-specific glutamate dehydrogenase (GDH), which is produced by both toxigenic and non-toxigenic strains. To confirm CDIs, it is necessary to test for toxins in a fresh, liquid stool sample via polymerase chain reaction or an enzyme-coupled immune adsorption test. If CDIs are diagnosed, then ongoing antibiotic treatment should be ended. Metronidazole is used to treat mild cases, and vancomycin is recommended for severe cases. Vancomycin or fidaxomicin should be used to treat recurrences (10-25 % of patients). In cases with several recurrences, a treatment option is fecal microbiome transfer (FMT). The cure rate following FMT is approximately 80 %. The treatment of severe and complicated CDI with a threatening toxic megacolon remains problematic. The degree of evidence of medicated treatment in this situation is low; the significance of metronidazole i. v. as an additional therapeutic measure is controversial. Tigecycline i. v. is an alternative option. Surgical treatment must be considered in patients with a toxic megacolon or an acute abdomen.

Minocycline and Tigecycline: What Is Their Role in the Treatment of Carbapenem-Resistant Gram-Negative Organisms?

Carbapenem-resistant organisms are increasingly common worldwide, particularly in India and are associated with high mortality rates especially in patients with severe infection such as bacteremia. Existing drugs such as carbapenems and polymyxins have a number of disadvantages, but remain the mainstay of treatment. The tetracycline class of antibiotics was first produced in the 1940s. Minocycline, tetracycline derivative, although licensed for treatment of wide range of infections, has not been considered for treatment of multidrug-resistant organisms until recently and needs further in vivo studies. Tigecycline, a derivative of minocycline, although with certain disadvantages, has been frequently used in the treatment of carbapenem-resistant organisms. In this article, we review the properties of minocycline and tigecycline, the common mechanisms of resistance, and assess their role in the management of carbapenem-resistant organisms.

Antimicrobial susceptibility of Brazilian Clostridium difficile strains determined by agar dilution and disk diffusion

Clostridium difficile is a leading cause of diarrhea in hospitalized patients worldwide. While metronidazole and vancomycin are the most prescribed antibiotics for the treatment of this infection, teicoplanin, tigecycline and nitazoxanide are alternatives drugs. Knowledge on the antibiotic susceptibility profiles is a basic step to differentiate recurrence from treatment failure due to antimicrobial resistance. Because C. difficile antimicrobial susceptibility is largely unknown in Brazil, we aimed to determine the profile of C. difficile strains cultivated from stool samples of inpatients with diarrhea and a positive toxin A/B test using both agar dilution and disk diffusion methods. All 50 strains tested were sensitive to metronidazole according to CLSI and EUCAST breakpoints with an MIC90 value of 2μg/mL. Nitazoxanide and tigecycline were highly active in vitro against these strains with an MIC90 value of 0.125μg/mL for both antimicrobials. The MIC90 were 4μg/mL and 2μg/mL for vancomycin and teicoplanin, respectively. A resistance rate of 8% was observed for moxifloxacin. Disk diffusion can be used as an alternative to screen for moxifloxacin resistance, nitazoxanide, tigecycline and metronidazole susceptibility, but it cannot be used for testing glycopeptides. Our results suggest that C. difficile strains from São Paulo city, Brazil, are susceptible to metronidazole and have low MIC90 values for most of the current therapeutic options available in Brazil.

Therapies on the horizon for Clostridium difficile infections

INTRODUCTION

Clostridium difficile infections are a leading cause of healthcare facility outbreaks of gastrointestinal illness that may have serious complications and a high rate of recurrent disease. Despite the availability of standard antibiotic treatments, data from national surveillance programs indicate that the incidence of this disease continues to increase, placing a heavy burden on healthcare systems. New emerging strategies are being tested to replace or augment these standard antibiotics.

AREAS COVERED

Thirty-two current investigational agents focusing on different strategies for both prevention and treatment of C. difficile infections are reviewed. Data was gathered from a literature search of public databases for published trials from 1999-November 13, 2015 and from the author's compendium of knowledge. Agents reviewed included 13 antibiotics, two antibiotic inactivators, seven bacteria or yeasts acting to enhance the normal microbiome, seven immunizing agents and three toxin binders. Of the 32 investigational treatments reviewed, 8 (25%) showed significant efficacy in phase II or III clinical trials and are actively being developed as new therapies for C. difficile infections.

EXPERT OPINION

A number of potential treatments have floundered during their development process, while others have shown promising results. The strongest efficacy has been in the areas of newer antibiotics, probiotics, monoclonal antibodies and vaccines. By targeting the pathogenic pathway of C. difficile infections, multiple strategies for prevention and treatment have been developed.