Clostridium difficile infection: current perspectives:

Clostridioides difficile ferrosome organelles combat nutritional immunity

Iron is indispensable for almost all forms of life but toxic at elevated levels1-4. To survive within their hosts, bacterial pathogens have evolved iron uptake, storage and detoxification strategies to maintain iron homeostasis1,5,6. Recent studies showed that three Gram-negative environmental anaerobes produce iron-containing ferrosome granules7,8. However, it remains unclear whether ferrosomes are generated exclusively by Gram-negative bacteria. The Gram-positive bacterium Clostridioides difficile is the leading cause of nosocomial and antibiotic-associated infections in the USA9. Here we report that C. difficile undergoes an intracellular iron biomineralization process and stores iron in membrane-bound ferrosome organelles containing non-crystalline iron phosphate biominerals. We found that a membrane protein (FezA) and a P1B6-ATPase transporter (FezB), repressed by both iron and the ferric uptake regulator Fur, are required for ferrosome formation and play an important role in iron homeostasis during transition from iron deficiency to excess. Additionally, ferrosomes are often localized adjacent to cellular membranes as shown by cryo-electron tomography. Furthermore, using two mouse models of C. difficile infection, we demonstrated that the ferrosome system is activated in the inflamed gut to combat calprotectin-mediated iron sequestration and is important for bacterial colonization and survival during C. difficile infection.

Investigation of metabolic crosstalk between host and pathogenic Clostridioides difficile via multiomics approaches

Clostridioides difficile is a gram-positive anaerobic bacterium that causes antibiotic-associated infections in the gut. C. difficile infection develops in the intestine of a host with an imbalance of the intestinal microbiota and, in severe cases, can lead to toxic megacolon, intestinal perforation, and even death. Despite its severity and importance, however, the lack of a model to understand host-pathogen interactions and the lack of research results on host cell effects and response mechanisms under C. difficile infection remain limited. Here, we developed an in vitro anaerobic-aerobic C. difficile infection model that enables direct interaction between human gut epithelial cells and C. difficile through the Mimetic Intestinal Host–Microbe Interaction Coculture System. Additionally, an integrative multiomics approach was applied to investigate the biological changes and response mechanisms of host cells caused by C. difficile in the early stage of infection. The C. difficile infection model was validated through the induction of disaggregation of the actin filaments and disruption of the intestinal epithelial barrier as the toxin-mediated phenotypes following infection progression. In addition, an upregulation of stress-induced chaperones and an increase in the ubiquitin proteasomal pathway were identified in response to protein stress that occurred in the early stage of infection, and downregulation of proteins contained in the electron transfer chain and ATP synthase was observed. It has been demonstrated that host cell energy metabolism is inhibited through the glycolysis of Caco-2 cells and the reduction of metabolites belonging to the TCA cycle. Taken together, our C. difficile infection model suggests a new biological response pathway in the host cell induced by C. difficile during the early stage of infection at the molecular level under anaerobic-aerobic conditions. Therefore, this study has the potential to be applied to the development of future therapeutics through basic metabolic studies of C. difficile infection.

Change in the Mortality Trend of Hospitalized Patients with Clostridium difficile Infection: A Nation-wide Study

Background According to the Healthcare Cost and Utilization Project (HCUP), mortality in Clostridium difficile infection (CDI) has been rising since 2009, and an upward trend in mortality has been noted. Although there have been studies exploring the incidence of CDI and mortality in the national database, those studies were limited to one particular year. With the advent of newer modalities of diagnosis and treatment for CDI, the recent multiyear trend in disease-specific outcomes from large administrative databases is unknown. Objective To study the recent trend in nationwide hospital admissions and mortality along with hospital outcomes. Methods We queried the identified National Inpatient Sample from 2007 to 2011 to identify patients of age >18 years, with a discharge diagnosis of CDI identified by the International Classification of Diseases, 9th edition (ICD-9), clinical modification codes 008.45, respectively. Results We identified a decline in CDI mortality to 2.67% in 2011 as compared to 3.83% in 2007 (P<0.0001) with CDI as the primary discharge diagnosis and a downward trend in all-cause mortality from 9.2% in 2007 to 7.9% in 2011 (P<0.0001). We identified an upward trend in CDI-related hospital discharges from 2007 (N=325,022) to 2011 (N=333498). Hospital discharges with CDI as a primary discharge diagnosis also increased from 2007 (N=104,123) to 2011 (123,898). The mean length of stay decreased from 7.16 days in 2007 to 6.40 days in 2011 (P 0.0001). CDI was noted to be more common in the elderly (61-80), with a mean age of 68 years. Patients were of Caucasian descent (67%), female (64%), and primarily a Medicare payer (69%). Mean hospital charges increased from $31,551 to 35,654$ (P .04). Of interest, CDI was noted to be more common in large bed-sized non-teaching hospitals (57%) than large bed-sized teaching hospitals (42%). In terms of the geographical distribution of CDI, the southern states of the US had an increased incidence of CDI (36%) and the west coast (16%) had the least incidence. Conclusion  Our study shows an improved trend in-hospital mortality outcomes and a decreased length of stay likely related to the advancement in CDI treatments. Hospital charges were increased from 2007 to 2011 in spite of a decrease in hospital length of stay.

A Clostridium difficile Cell Wall Glycopolymer Locus Influences Bacterial Shape, Polysaccharide Production and Virulence

Clostridium difficile is a diarrheagenic pathogen associated with significant mortality and morbidity. While its glucosylating toxins are primary virulence determinants, there is increasing appreciation of important roles for non-toxin factors in C. difficile pathogenesis. Cell wall glycopolymers (CWGs) influence the virulence of various pathogens. Five C. difficile CWGs, including PSII, have been structurally characterized, but their biosynthesis and significance in C. difficile infection is unknown. We explored the contribution of a conserved CWG locus to C. difficile cell-surface integrity and virulence. Attempts at disrupting multiple genes in the locus, including one encoding a predicted CWG exporter mviN, were unsuccessful, suggesting essentiality of the respective gene products. However, antisense RNA-mediated mviN downregulation resulted in slight morphology defects, retarded growth, and decreased surface PSII deposition. Two other genes, lcpA and lcpB, with putative roles in CWG anchoring, could be disrupted by insertional inactivation. lcpA^- and lcpB^- mutants had distinct phenotypes, implying non-redundant roles for the respective proteins. The lcpB^- mutant was defective in surface PSII deposition and shedding, and exhibited a remodeled cell surface characterized by elongated and helical morphology, aberrantly-localized cell septae, and an altered surface-anchored protein profile. Both lcpA^- and lcpB^- strains also displayed heightened virulence in a hamster model of C. difficile disease. We propose that gene products of the C. difficile CWG locus are essential, that they direct the production/assembly of key antigenic surface polysaccharides, and thereby have complex roles in virulence.

Clostridium difficile infection is a leading healthcare-onset bacterial disease, and its management and prevention imposes significant clinical and financial burdens worldwide. While toxins TcdA and TcdB are the primary virulence factors, there is increasing interest in, and appreciation of, non-toxin virulence factors in C. difficile pathogenesis. Cell wall glycopolymers (CWGs) are important virulence determinants in many pathogens, but their role(s) in C. difficile pathogenesis is unclear. We propose a model for C. difficile CWG biosynthesis, and demonstrate that alterations in cell wall assembly profoundly impact bacterial morphology and virulence.

The effect of statins on the outcome of Clostridium difficile infection in hospitalized patients

Several studies have shown an association between exposure to statins and favorable clinical outcomes for various types of infections. We aimed to assess the impact of statin use on mortality, disease severity and complications among hospitalized patients with Clostridium difficile infection (CDI). Data were analyzed from a retrospectively collected database of 499 patients diagnosed with CDI during 2009-2014. We compared infection outcomes between 178 statin (36 %) users and 321 (64 %) non-users. On multivariate analysis, we found that statin use did not have a significant impact on 30-day mortality (OR = 1.54; 95 % CI, 0.85-2.79; p = 0.15) or any significant effect on CDI severity and complication. Concomitant statin use has no significant impact on short-term mortality or effect on CDI severity and complications among hospitalized patients with CDI. However, patients in the statin group were older and had higher Charlson score compared with the non-statin group. Whether these factors affected a possible impact of statins on the disease course remains to be investigated.

KEY MESSAGES

• Clostridium difficile is the most common cause of infectious nosocomial diarrhea among hospitalized adult patients in the developed countries. • There is an increasing morbidity and mortality of CDI patients due to the emergence of new strains of high virulence. • Recent studies demonstrated that prior statin use has protective and ameliorating effects on morbidity and mortality among CDI patients. • Our study showed that concomitant statin use has no significant impact on short-term mortality, CDI severity and its complications.

Predictors and outcomes of readmission for Clostridium difficile in a national sample of medicare beneficiaries

BACKGROUND

Rates of Clostridium difficile (CD) infections are increasing. Elderly patients may be at particular risk of recurrent CD infection. Little is known about the risk for CD readmission specifically in this age group.

METHODS

A 5% random sample of Medicare data (2009-2011) was queried for patients surviving a hospitalization for CD by ICD-9 code. Demographic (age, sex, gender), clinical (Elixhauser index, gastrointestinal comorbidities), and hospitalization (length of stay, ICU admission) characteristics as well as exposure to antibiotics and interim non-CD hospitalization were compared for those with and without a readmission for CD. A multivariable survival analysis was used to determine predictors of readmission.

RESULTS

Of 7,564 patients surviving a CD hospitalization, 8.5% were readmitted with CD in a median of 25 days (interquartile range (IQR) 14-57). In multivariable survival analyses, interim non-CD hospital exposure was the strongest predictor of CD readmission (hazard ration (HR) 3.75 95%, confidence interval (CI) 3.2-4.42). Oral and intravenous/intramuscular (IV/IM) antibiotic use, Elixhauser index, and CD as the primary diagnosis also increased the risk of CD readmission. Discharge to hospice, long-term care or a skilled nursing facility decreased the odds of CD readmission.

CONCLUSION

Hospital exposure and antibiotic use put elderly patients at risk of CD readmission. Exposure to these factors should be minimized in the immediate post discharge period.

Statins use and risk of mortality in patient with Clostridium difficile infection

Current evidence suggests that statins may improve outcome in infectious diseases. This study aims to assess whether statins use is associated with reduced risk of 30-day mortality in Clostridium difficile infection (CDI). Using the computerized database of Clalit, the largest healthcare provider in Israel, we identified a cohort of adult subjects (age ≥40 years) who tested positive on a C. difficile toxin assay performed between January 2011 and December 2012. Subjects were defined as current statins users if they filled at least one prescription during the 90 days before the laboratory assay date. Current users were classified into long-term users if at least one additional prescription was filled during the previous 91-180 days; otherwise they were defined as short-term users. A total 1888 patients with CDI were included. Of them, 340 (18.0%) died during the first 30 days after diagnosis. The 30-day mortality rate was lower among current statins users 89/669 (13.3%) compared with 251/1219 (20.6%) in non-users (p <0.001). A significant reduced risk of 30-day mortality existed after adjustment for potential confounders; adjusted OR = 0.57 (95% CI 0.42-0.79) and was unique to long-term users; 0.53 (0.38-0.73) but not short-term users; 1.15 (0.56-2.34). The risk of 30-day mortality decreased with increasing number of filled statins prescriptions; adjusted OR = 0.77 (95% CI 0.67-0.89) for each additional prescription. Current aspirin use was also independently associated with reduced mortality; adjusted OR = 0.64 (95% CI 0.43-0.88). In conclusion, current statins use, particularly long-term use, has a dose-response protective effect on mortality in patients with CDI.

Right to know: reducing risks of fecal pathogen exposure for ED patients and staff

INTRODUCTION

The purpose of this article is to review the literature regarding the multiple challenges that contribute to ED bedside toileting and examine best practices that will reduce fecal exposure, cross-contamination among patients, and employee splash injuries.

METHODS

We searched the Cumulative Index to Nursing and Allied Health Literature, MEDLINE, and Cochrane database for information about the multiple challenges involved in bedside toileting, using the following search terms: bedside toileting, gastroenteritis, macerator, sluice machine, fecal pathogen exposure, and splash injury. In addition, costs and benefits of reusable versus disposable bedside toileting equipment were compared and contrasted.

DISCUSSION

Emergency departments have a higher exposure rate to fecal pathogens with current methods of bedside toileting. Short incubation periods may not allow the proper lead time needed for patients to access primary care providers. As a result, emergency departments and urgent care centers become a likely point of entry into the health care system. Although most inpatient rooms have built-in bathrooms, most emergency departments and outpatient examination rooms do not. Although many patients are ambulatory, restrictive monitoring equipment is required. For safety reasons, staff must bring toileting equipment to the bedsides of both ambulatory and non-ambulatory patients. Hopper dependence creates longer walking distances and delays. These delays may lead to incontinence events, skin breakdown, more frequent bed changes, and higher linen and labor costs. Reusable bedside toileting equipment is associated with at-risk behaviors. Examples are procrastination and sanitization shortcuts. These behaviors risk cross-contamination of patients especially when urgent situations require equipment to be reused in the interim. ED patients and staff are 5 times more likely to undergo fecal exposure. The 5 phases of ED bedside toileting at which risks occur are as follows: equipment setup, transport of human waste to drainage areas, transfer of waste, pre-cleaning, and equipment disinfection. Therefore it is imperative that ED staff have a full understanding of hazardous materials involved, know safer bedside toileting practices, and have safer equipment available to protect all involved. Upgrading our knowledge, equipment, and practices must become a higher priority for ED leadership.

BIASES/DISCLOSURES

The East Bank Emergency Department of the University of Minnesota Medical Center, Fairview, will be moving toward 100% disposable bedside commode pails in addition to disposable bedpans, currently in use. On the basis of a literature review to understand best-practice ED bedside toileting, the following article was created. As a result of our learning, the University of Minnesota Medical Center emergency staff has designed, patented, and developed a landfill-compliant disposable commode pail that absorbs waste while reducing splashes and spills. Disposable commode pails (bags) are conveniently wall mounted for quick availability, and "at-risk behavior" is reduced. Advantages are all point-of-care. Both setup and waste treatment and disposal start and end at the bedside. The advantages are faster response times, reduction of soiled linens and bed changes, prevention of incontinence and skin breakdown events, and reduced splash injuries or pathogen transmission. Patient satisfaction improves with shorter bedside toileting delays. Employee satisfaction increases with reduced human waste handling. The cost of each unit is comparable to an adult overnight diaper. Bariatric commode pails or bags are in the planning phase, and a "green" disposable commode pail, made from biodegradable corn byproducts, will be made available at a higher cost.

Length of stay and mortality due to Clostridium difficile infection acquired in the intensive care unit

PURPOSE

The purpose of this study was to determine the attributable intensive care unit (ICU) and hospital length of stay and mortality of ICU-acquired Clostridium difficile infection (CDI).

MATERIALS AND METHODS

In this retrospective cohort study of 3 tertiary and 3 community ICUs, we screened all patients admitted between April 2006 and December 2011 for ICU-acquired CDI. Using both complete and matched cohort designs and Cox proportional hazards analysis, we determined the association between CDI and ICU and hospital length of stay and mortality. Adjustment or matching variables were site, age, sex, severity of illness, and year of admission; any infection as an ICU admitting or acquired diagnosis before the diagnosis of CDI and diagnosis of CDI were time-dependent exposures.

RESULTS

Of 15314 patients admitted to the ICUs during the study period, 236 developed CDI in the ICU. In the complete cohort analysis, the hazard ratios (95% confidence interval) for CDI related to ICU and hospital discharge were 0.82 (0.72, 0.94) and 0.83 (0.73, 0.95), respectively (0.5 additional ICU days and 3.4 hospital days), and related to death in ICU and hospital, they were 1.00 (0.73, 1.38) and 1.19 (0.93, 1.52), respectively. In the matched analysis, the hazard ratios for CDI related to ICU and hospital discharge were 0.91 (0.81, 1.03) and 0.98 (0.85, 1.13), respectively, and related to death in ICU and hospital, they were 1.18 (0.85, 1.63) and 1.08 (0.82, 1.43), respectively.

CONCLUSIONS

C difficile infection acquired in ICU is associated with an increase in length of ICU and hospital stay but not with any difference in ICU or hospital mortality.

Clostridium difficile infection in older adults: a review and update on its management

BACKGROUND

Clostridium difficile is a main cause of health care-associated infections. The incidence and severity have been increasing. Elderly persons are at an increased risk of morbidity and mortality from C. difficile infection (CDI). Relatively few advances have been made in the treatment of CDI since it was first identified as a cause of antibiotic-associated diarrhea more than 30 years ago.

OBJECTIVE

This article reviews CDI and provides an update on its treatment, including recently published clinical practice guidelines and the recently approved drug, fidaxomicin.

METHODS

English-language literature was identified through a search of PubMed (1966-October 2011), Iowa Drug Information Service (1966-October 2011), and International Pharmaceutical Abstracts (1970-October 2011). Key search terms included Clostridium difficile, Clostridium infections, pseudomembranous colitis, antibiotic-associated diarrhea, Clostridium difficile-associated diarrhea, elderly, geriatric, epidemiology, microbiology, diagnosis, risk factors, treatment, drug therapy, vancomycin, metronidazole, and fidaxomicin.

RESULTS

Metronidazole and vancomycin remain the mainstays of CDI treatment. Current guidelines recommend oral metronidazole for initial mild to moderate episodes or first recurrence. Oral vancomycin is recommended for initial severe episodes, or first or second recurrence. Fidaxomicin was approved in 2011 for treatment of CDI, but its place in therapy has yet to be determined. Other antibiotics have been used with variable success. Saccharomyces boulardii is the only probiotic that has shown efficacy in CDI. Fecal transplants have been used successfully in some patients, but randomized studies are needed. Immune therapy with a vaccine and monoclonal antibodies is being studied in clinical trials.

CONCLUSIONS

Treatment of CDI is challenging due to the limited number of drugs that have proven to be effective, concerns about antibiotic resistance, and recurring disease. The recent approval of fidaxomicin provides a new alternative. Immune therapy will likely play a greater role in the future.

Incidence and risk factors for lower alimentary tract mucositis after 1529 courses of chemotherapy in a homogenous population of oncology patients: clinical and research implications

BACKGROUND

Lower alimentary tract mucositis is a serious complication of chemotherapy. The aim of the study was to determine the incidence, risk factors, and mortality of lower alimentary tract mucositis in a homogeneous population of patients with newly diagnosed myeloma receiving similar antineoplastic therapy and standardized supportive care.

METHODS

Lower alimentary tract mucositis was evaluated among 303 consecutive patients with myeloma (2004-2007) enrolled in a clinical trial consisting of induction chemotherapy, tandem melphalan-based autologous stem cell transplantation (ASCT), and consolidation. Lower alimentary tract mucositis was defined as neutropenia-associated grade II-IV enteritis/colitis. Pretreatment risk factors were examined including body surface area (BSA), serum albumin (albumin), and estimated creatinine clearance (CrCl). Multiple logistic regression model was used to compute adjusted odds ratio (OR) and 95% confidence intervals (CI).

RESULTS

Forty-seven (15.5%) patients developed lower alimentary tract mucositis during 1529 courses of chemotherapy (including 536 melphalan-based ASCT). Pre-enrollment BSA <2 m² (OR, 2.768; 95% CI, 1.200-6.381; P = .0169) increased the risk for lower alimentary tract mucositis, whereas higher albumin was protective (OR, 0.698; 95% CI, 0.519-0.940; P = .0177). Pretransplant variables associated with lower alimentary tract mucositis were BSA <2 m² (OR, 4.451; 95% CI, 1.459-13.58, P = .0087) and estimated CrCl <60 mL/min (OR, 3.493; 95% CI, 1.173-10.40; P = .0246). Higher albumin level conferred protection (OR, 0.500; 95% CI, 0.304-0.820; P = .0061). No lower alimentary tract mucositis-related death was observed.

CONCLUSIONS

Lower alimentary tract mucositis is not uncommon among a homogenous population of oncology patients undergoing sequential courses of chemotherapy including melphalan-based ASCT but does not contribute to mortality. Lower BSA, renal function, and albumin are associated with increased risk for lower alimentary tract mucositis.

Clostridium difficile-associated disease acquired in the neurocritical care unit

BACKGROUND

Clostridium difficile is an important cause of nosocomial infection on the intensive care unit. Little is known about infection rates on the neurocritical care unit (NICU). The purpose of this study was to determine the prevalence, severity, and outcome associated with Clostridium difficile-associated disease (CDAD) acquired on the NICU.

METHODS

Patients on NICU with a positive stool Clostridium difficile toxin assay, from August 2004 to February 2008, were identified by the Department of Microbiology. Each patient's medical notes and charts were reviewed in turn. Patients with a positive assay within 48 h of NICU admission were excluded.

RESULTS

Twenty-one (0.6%) NICU patients developed CDAD. All were emergency admissions, 18 (86.0%) were neurosurgical. Subarachnoid hemorrhage was the most common diagnosis, 5 (23.8%) patients. Median age and APACHE II score on admission were 55 (IQR 40-66) and 21 (IQR 16-24), respectively. Thirteen (61.9%) patients were female. Median interval between NICU admission and diarrhea onset and CDAD diagnosis were 5 (3-8) days and 7 (4-12) days, respectively. At the time of diagnosis most, 11 (52.4%) patients, had moderate CDAD. Previously identified risk factors for ICU-acquired CDAD comprised: age > 65 (6), antibiotics (21), and medical device requirements (21). Five (23.8%) patients deteriorated clinically as a result of CDAD. The overall in-hospital mortality for those with NICU acquired CDAD was 19%.

CONCLUSIONS

Although CDAD is rarely acquired on the NICU, up to one quarter of affected patients may experience complications. Prospective validation of severity definitions and treatment guidelines may help to reduce the complication rates.

Clostridium difficile infection: An overview of the disease and its pathogenesis, epidemiology and interventions

Clostridium difficile infection (CDI) is the primary cause of antibiotic-associated diarrhea and is a significant nosocomial disease. In the past ten years, variant toxin-producing strains of C. difficile have emerged, that have been associated with severe disease as well as outbreaks worldwide. This review summarizes current information on C. difficile pathogenesis and disease, and highlights interventions used to combat single and recurrent episodes of CDI.

[New antibiotics: small or big advances?]

This contribution summarizes the "state-of-the-art" in the field of new antibiotics. On the one hand interesting new substances are discussed, on the other hand areas of interest for more research are shown. Doripenem is a new broad-spectrum antibiotic which proved superior to other carbapenems as far as gram-negative bacilli were concerned and also showed less development of resistance. For the treatment of methicillin-resistant Staphylococcus aureus (MRSA), linezolid, tigecyclin and daptomycin reached drug approval within recent years. The new glycopeptides and iclaprim await approval. The majority of these substances are also effective against other resistant organisms like vancomycin-intermediate Staph. aureus and vancomycin-resistant entercoccus. Increasing virulence of some Clostridium difficile strains (particularly ribotype 027) within the past years has led to a growing need for new strategies concerning treatment and prophylaxis of Clostridium difficile associated diarrhea.