Elemental diet modulates the growth of Clostridium difficile in the gut flora

Impact of Clostridioides Difficle Infection and its Therapy on Nutritional Status

PURPOSE OF REVIEW

Clostridiodes difficile infection (CDI) is a leading nosocomial cause of increased morbidity and mortality in hospitalized patients and the presentation can vary from asymptomatic infection to severe fulminant colitis and sepsis. It can significantly impact nutritional status in hospitalized patients and lead to longer length of stay with increased morbidity and mortality.

RECENT FINDINGS

An interplay of various intrinsic and extrinsic factors such as systemic inflammation, diarrheal losses, and impact of isolation influence the nutritional status of patients with CDI. While diarrheal losses can lead to dehydration and electrolyte disturbances, isolation can further hamper adequate nutritional support and make early signs of malnutrition overlooked. Similar detrimental impacts on nutritional status can also be observed in other bacterial and viral colonic infections. While prompt diagnosis and early treatment is crucial to prevent mortality, emphasis on nutritional rehabilitation can help reduce morbidity and promote recovery in CDI. Initiation of early feeding in critically sick patients with close monitoring for early signs of malnutrition promotes favorable outcomes.

Fiber Composition in Sows' Diets Modifies Clostridioides difficile Colonization in Their Offspring

Dietary fiber has a potential to modulate the gut microbiota in sows. We hypothesized that a maternal diet rich in either high- or low-fermentable fiber during gestation and lactation influences Clostridioides difficile gut colonization in suckling piglets. Twenty sows were fed gestation and lactation diets enriched with either high-fermentable sugar beet pulp (SBP) or low-fermentable lignocellulose (LNC) fibers. C. difficile, toxin B (TcdB), fecal score, microbial abundance (16S-rDNA sequencing) and metabolites were measured in the feces from the sows and their piglets. C. difficile concentration was higher in piglets from the sows fed LNC than SBP along the study (P ≤ 0.05). Higher prevalence of C. difficile was noted in three-week-old piglets from sows fed LNC vs. SBP (45% vs. 0%, P = 0.001). TcdB prevalence was higher in six-day-old piglets from the sows fed LNC vs. SBP (60% vs. 17%, P = 0.009). In sows, fecal microbial metabolites were higher in SBP than LNC, while C. difficile concentration showed no difference. Higher microbial diversity Shannon index was noted in sows from SBP vs. LNC one week before parturition and at the parturition (P ≤ 0.05). Piglets from SBP vs. LNC tended to have higher microbial diversity Shannon index at two and three weeks of age. Diets enriched with high-fermentable fiber compared to low-fermentable fiber in sows reduced C. difficile colonization in their piglets. Susceptibility to colonization by C. difficile in neonatal piglets can be modulated by the sows' diet, supporting the hypothesis of the early microbial programming in the offspring and the importance of the sow-piglet couple.

Vulnerability of long-term care facility residents to Clostridium difficile infection due to microbiome disruptions

Aging presents a significant risk factor for Clostridium difficile infection (CDI). A disproportionate number of CDIs affect individuals in long-term care facilities compared with the general population, likely due to the vulnerable nature of the residents and shared environment. Review of the literature cites a number of underlying medical conditions such as the use of antibiotics, proton pump inhibitors, chemotherapy, renal disease and feeding tubes as risk factors. These conditions alter the intestinal environment through direct bacterial killing, changes to pH that influence bacterial stabilities or growth, or influence nutrient availability that direct population profiles. In this review, we examine some of the contributing risk factors for elderly associated CDI and the toll they take on the microbiome.

Impact of early-life events on the susceptibility to Clostridium difficile colonisation and infection in the offspring of the pig

Clostridium difficile has been documented as a major cause of uncontrolled outbreaks of enteritis in neonatal pigs and antibiotic-associated infections in clinical settings. It belongs to the natural cohort of early colonisers of the gastrointestinal tract of pigs and can be detected in faeces up to two weeks post-partum. In older pigs, it often remains under the detection limit. Most neonatal pigs show no clinical signs of disease although C. difficile and its toxins can be detected at high levels in faeces. Increased mortality rates associated with C. difficile on pig farms are, so far, considered "spontaneous" and the predisposing factors are mostly not defined. The infection caused by C. difficile is multifactorial and it is likely that the repertoire of maternal factors, host physiology, the individually developing gut microbiota, co-infections and environmental stress define the conditions for disease development. In this addendum to our recently published work on CDI in neonatal piglets, we discuss the "early-life events" that influence C. difficile spread and infection in neonatal piglets.

[Clinical and demographic profile and risk factors for Clostridium difficile infection]

INTRODUCTION

Clostridium difficile infection is the leading cause of nosocomial infectious diarrhea. The increasing incidence added to a lower rate of response to the initial treatment and higher rates of relapse has generated a higher burden of the disease.

OBJECTIVE

To determine the clinical characteristics of hospitalized patients with C. difficile infection.

MATERIALS AND METHODS

We made a nested case-cohort study. We reviewed medical records of the patients with nosocomial diarrhea for whom an assay for toxin A-B of C. difficile had been requested from February, 2010, to February, 2012. We defined case as a patient with diarrhea and a positive assay for the toxin, and control as those patients with a negative assay for the toxin. We collected data on demographic and clinical characteristics, risk factors, hospital length of stay, treatment, and complications.

RESULTS

We collected data from 123 patients during the follow-up period, 30 of whom were positive for the toxin. Mean age in the study population was 49 years and 60% were men. The main symptoms were abdominal pain (35%) and fever (34%). The principal complications were electrolytic alteration and severe sepsis with secondary acute kidney injury. Mortality was 13% and independent factors associated to the appearance of the infection were the use of proton pump inhibitors and previous gastrointestinal tract surgery.

CONCLUSIONS

The use of proton pump inhibitors and previous gastrointestinal tract surgery were factors associated to C. difficile infection.

Comparative nutritional and chemical phenome of Clostridium difficile isolates determined using phenotype microarrays

OBJECTIVES

Clostridium difficile infection (CDI) is the leading cause of infectious diarrhea in North America and Europe. The risk of CDI increases significantly in the case where antimicrobial treatment reduces the number of competing bacteria in the gut, thus leading to the increased availability of nutrients and loss of colonization resistance. The objective of this study was to determine comprehensive nutritional utilization and the chemical sensitivity profile of historic and newer C. difficile isolates and to examine the possible role of the phenotype diversity in C. difficile virulence.

METHODS

Phenotype microarrays (PMs) were used to elucidate the complete nutritional and chemical sensitivity profile of six C. difficile isolates.

RESULTS

Of the 760 nutrient sources tested, 285 compounds were utilized by at least one strain. Among the C. difficile isolates compared, R20291, a recent hypervirulent outbreak-associated strain, appears to have an expanded nutrient utilization profile when compared to all other strains.

CONCLUSIONS

The expanded nutritional utilization profile of some newer C. difficile strains could be one of the reasons for infections in patients who are not exposed to the hospital environment or not undergoing antibiotic treatment. This nutritional profile could be used to design tube feeding formulas that reduce the risk of CDI.

New Drugs and Strategies for Management of Clostridium difficile Colitis

Approaches for management of Clostridium difficile infection continually evolve as research reveals shifts in epidemiology, microbial pathogenesis, disease severity states, and response to therapy. These new discoveries significantly impact diagnostic and therapeutic strategies, given the high morbidity associated with this common nosocomial infectious diarrhea. Critically ill patients are at an increased risk of developing diarrheal illness like C. difficile and succumbing to potentially fatal complications of this infection. Early diagnosis of severe disease state may improve patient outcomes. In this article, we review treatment strategies and new approaches for the management of C. difficile in critically ill patients.

The intestinal microbiota dysbiosis and Clostridium difficile infection: is there a relationship with inflammatory bowel disease?

Gut microbiota is a compilation of microorganisms dwelling in the entire mammalian gastrointestinal tract. They display a symbiotic relationship with the host contributing to its intestinal health and disease. Even a slight fluctuation in this equipoise may be deleterious to the host, leading to many pathological conditions like Clostridium difficile infection or inflammatory bowel disease (IBD). In this review, we focus on the role of microbial dysbiosis in initiation of C. difficile infection and IBD, and we also touch upon the role of specific pathogens, particularly C. difficile, as causative agents of IBD. We also discuss the molecular mechanisms activated by C. difficile that contribute to the development and exacerbation of gastrointestinal disorders.

Transient fecal shedding and limited animal-to-animal transmission of Clostridium difficile by naturally infected finishing feedlot cattle

To longitudinally assess fecal shedding and animal-to-animal transmission of Clostridium difficile among finishing feedlot cattle as a risk for beef carcass contamination, we tested 186 ± 12 steers (mean ± standard deviation; 1,369 samples) in an experimental feedlot facility during the finishing period and at harvest. Clostridium difficile was isolated from 12.9% of steers on arrival (24/186; 0 to 33% among five suppliers). Shedding decreased to undetectable levels a week later (0%; P < 0.001), and remained low (< 3.6%) until immediately prior to shipment for harvest (1.2%). Antimicrobial use did not increase fecal shedding, despite treatment of 53% of animals for signs of respiratory disease. Animals shedding C. difficile on arrival, however, had 4.6 times higher odds of receiving antimicrobials for respiratory signs than nonshedders (95% confidence interval for the odds ratio, 1.4 to 14.8; P = 0.01). Neither the toxin genes nor toxin A or B was detected in most (39/42) isolates based on two complementary multiplex PCRs and enzyme-linked immunosorbent assay testing, respectively. Two linezolid- and clindamycin-resistant PCR ribotype 078 (tcdA+/tcdB+/cdtB+/39-bp-type deletion in tcdC) isolates were identified from two steers (at arrival and week 20), but these ribotypes did not become endemic. The other toxigenic isolate (tcdA+/tcdB+/cdtB+/classic tcdC; PCR ribotype 078-like) was identified in the cecum of one steer at harvest. Spatio-temporal analysis indicated transient shedding with no evidence of animal-to-animal transmission. The association between C. difficile shedding upon arrival and the subsequent need for antimicrobials for respiratory disease might indicate common predisposing factors. The isolation of toxigenic C. difficile from bovine intestines at harvest highlights the potential for food contamination in meat processing plants.

Tube feeding, the microbiota, and Clostridium difficile infection

Clostridium difficile (C. difficile) is now the leading cause of nosocomial diarrhea in the USA, accounting for 30% of patients with antibiotic-associated diarrhea, 70% of those with antibiotic-associated colitis, and most cases of pseudomembranous colitis. The organism has evolved over the last 8 years to become more virulent and resistant to antimicrobials (NAP1/027 strain) causing a more severe form of the disease that has increased mortality and healthcare costs. While it is generally accepted that the problem results from the overuse of antibiotics, and in particular second and third generation cephalosporins, fluoroquinolones and macrolides, recent studies suggest that acid suppression with proton pump inhibitors (PPIs) may be equally culpable. A further common, but less recognized, etiological factor is the prolonged use of elemental diets. Such diets are totally absorbed within the small intestine and therefore deprive the colonic microbiota of their source of nutrition, namely dietary fiber, fructose oligosaccharides, and resistant starch. The resultant suppression of colonic fermentation leads to suppression of the “good” bacteria, such as butyrate-producers (butyrate being essential for colonic mucosal health), and bifidobacteria and the creation of a “permissive” environment for C. difficile colonization and subsequent infection. Based on this analysis, the best chance of suppressing the emerging C. difficile epidemic is to adopt a 3-pronged attack consisting of (1) avoidance of the use of prophylactic antibiotics, (2) the avoidance of prophylactic PPIs, and (3) the conversion of elemental diet feeding to a diet containing adequate indigestible carbohydrate after the first week of critical illness. In this review, we highlight the rising worldwide incidence of C. difficile associated diarrhea and the role played by non-residue diets in destabilizing the colonic microbiota.

Clostridium difficile and the disease it causes

Clostridium difficile is a spore-forming, toxin-producing, anaerobic bacterium abundant in soils and water. Frequent and early colonization of the human intestinal flora is common and often asymptomatic. Antimicrobials given commonly disrupt the intestinal microflora and through proliferation in colon and production of toxin A and B it precipitates C. difficile infection (CDI). The enterocytic detachment and bowel inflammation provoke C. difficile-associated diarrhoea (CDAD) sometimes developing into severe pseudomembranous colitis (PMC) and paralytic ileus. Infection is acquired from an endogenous source or from spores in the environment, most easily facilitated during hospital stay. In the elderly, comorbidity, hospitalization and antimicrobial treatment present as major risk factors and the slow recolonization of the normal flora likely responsible for single or multiple recurrences of CDI (25-50%) post therapy. The key procedure for diagnosis is toxin detection from stool specimens and sometimes in combination with culture to increase sensitivity. In mild cases stopping the offending antimicrobial will lead to resolution (25%) but standard therapy still consist of either oral metronidazole or vancomycin. Alternative agents are presently being developed and fidaxomicin, as well as nitrothiazolide are promising. Furthermore, host factors like low antitoxin A levels in serum relates to increased risk of recurrence and small numbers of patients have received immunoglobulin with good results. An immunogenic toxoid vaccine has been developed and human colostrum rich in specific secretory Ig A also support the future use of immunotherapy. Today we experience a tenfold increase of CDI incidence in the western world and both epidemics and therapeutic failure of metronidazole is contributing to morbidity and mortality. The current epidemic of the C. difficile strain NAP1/027 emerging in 2002 in Canada and the USA has now spread to most parts of Europe and virulence factors like high toxin production and sporulation challenge the therapeutic situation and cause great concern among infection control workers. Excessive use of modern fluoroquinolones is thought to play an important role in facilitating this epidemic since NAP1/027 was shown to have acquired moxifloxacin resistance compared to historical strains of the same genotype. Both the current epidemic like this and other local outbreaks from resistant or virulent strains warrant culture to be routinely performed enabling susceptibility testing and typing of the pathogen. Genotyping is most commonly done today by pulse-field gel electrophoresis (PFGE) or PCR ribotyping but multilocus variable-number tandem-repeat analysis (MLVA) seems promising. Epidemiological surveillance using all these tools will help us to better understand the global spread of C. difficile.

Frequent emergence of resistance in Clostridium difficile during treatment of C. difficile-associated diarrhea with fusidic acid

Samples from patients with Clostridium difficile-associated diarrhea (CDAD) that were randomized to fusidic acid (n = 59) or metronidazole (n = 55) therapy for 7 days were cultured for Clostridium difficile in feces on days 1, 8 to 13, and 35 to 40. Of the patients who were culture positive only before treatment, 77% (36/47) were permanently cured (no treatment failure and no clinical recurrence), compared to 54% (22/41) of those with persistence of C. difficile at one or both follow-ups (P = 0.03). A similar association between bacterial persistence and a worse outcome of therapy was seen in both treatment groups. Resistance to fusidic acid was found in 1 of 88 pretherapy isolates available, plus in at least 1 subsequent isolate from 55% (11/20) of patients who remained culture-positive after fusidic acid therapy. In 10 of these 11 patients, the resistant follow-up isolate(s) belonged to the same PCR ribotype as the susceptible day 1 isolate, confirming frequent emergence of resistance to fusidic acid during treatment. Despite this, 5 of these 11 patients were permanently cured with fusidic acid, relative to 5 of 9 patients with susceptible C. difficile at follow-up (P = 1.0). None of the 36 PCR ribotypes of C. difficile identified was associated with any particular clinical outcome or emergence of fusidic acid resistance. In conclusion, culture positivity for C. difficile was common after both fusidic acid and metronidazole therapy and was associated with treatment failure or recurrence of CDAD. Development of resistance in C. difficile was frequent in patients given fusidic acid, but it was without apparent negative impact on therapeutic efficacy in the actual CDAD episode.

Novel evidence suggesting Clostridium difficile is present in human gut microbiota more frequently than previously suspected

Prevalence rate of Clostridium difficile in healthy human adults is believed to be very low. Our RT-PCR system using glass powder, which can eliminate PCR inhibitors, detected C. difficile toxin B mRNA in 16 of 30 fecal samples (53.3%) from healthy human adults. In contrast, we failed to detect toxin B in the same fecal samples by PCR using DNA templates extracted with phenol-chloroform. Our results suggest that PCR inhibitors in feces carried through phenol-chloroform extraction procedure might suppress the sensitivity of PCR and that C. difficile is actually present in human gut microbiota more frequently than previously suspected.