Outcomes of Clostridium difficile infection in hospitalized leukemia patients: a nationwide analysis. Infect Control Hosp Epidemiol. 2015;36:794-801. [PMID: 25801085 DOI: 10.1017/ice.2015.54]

Clostridioides difficile Toxins: Host Cell Interactions and Their Role in Disease Pathogenesis

Clostridioides difficile, a Gram-positive anaerobic bacterium, is the leading cause of hospital-acquired antibiotic-associated diarrhea worldwide. The severity of C. difficile infection (CDI) varies, ranging from mild diarrhea to life-threatening conditions such as pseudomembranous colitis and toxic megacolon. Central to the pathogenesis of the infection are toxins produced by C. difficile, with toxin A (TcdA) and toxin B (TcdB) as the main virulence factors. Additionally, some strains produce a third toxin known as C. difficile transferase (CDT). Toxins damage the colonic epithelium, initiating a cascade of cellular events that lead to inflammation, fluid secretion, and further tissue damage within the colon. Mechanistically, the toxins bind to cell surface receptors, internalize, and then inactivate GTPase proteins, disrupting the organization of the cytoskeleton and affecting various Rho-dependent cellular processes. This results in a loss of epithelial barrier functions and the induction of cell death. The third toxin, CDT, however, functions as a binary actin-ADP-ribosylating toxin, causing actin depolymerization and inducing the formation of microtubule-based protrusions. In this review, we summarize our current understanding of the interaction between C. difficile toxins and host cells, elucidating the functional consequences of their actions. Furthermore, we will outline how this knowledge forms the basis for developing innovative, toxin-based strategies for treating and preventing CDI.

Host Immune Responses to Clostridioides difficile Infection and Potential Novel Therapeutic Approaches

Clostridioides difficile infection (CDI) is a leading nosocomial infection, posing a substantial public health challenge within the United States and globally. CDI typically occurs in hospitalized elderly patients who have been administered antibiotics; however, there has been a rise in the occurrence of CDI in the community among young adults who have not been exposed to antibiotics. C. difficile releases toxins, which damage large intestinal epithelium, leading to toxic megacolon, sepsis, and even death. Unfortunately, existing antibiotic therapies do not always prevent these consequences, with up to one-third of treated patients experiencing a recurrence of the infection. Host factors play a crucial role in the pathogenesis of CDI, and accumulating evidence shows that modulation of host immune responses may potentially alter the disease outcome. In this review, we provide an overview of our current knowledge regarding the role of innate and adaptive immune responses on CDI outcomes. Moreover, we present a summary of non-antibiotic microbiome-based therapies that can effectively influence host immune responses, along with immunization strategies that are intended to tackle both the treatment and prevention of CDI.

Host Immunity and Immunization Strategies for Clostridioides difficile Infection

Clostridioides difficile infection (CDI) represents a significant challenge to public health. C. difficile-associated mortality and morbidity have led the U.S. CDC to designate it as an urgent threat. Moreover, recurrence or relapses can occur in up to a third of CDI patients, due in part to antibiotics being the primary treatment for CDI and the major cause of the disease. In this review, we summarize the current knowledge of innate immune responses, adaptive immune responses, and the link between innate and adaptive immune responses of the host against CDI. The other major determinants of CDI, such as C. difficile toxins, the host microbiota, and related treatments, are also described. Finally, we discuss the known therapeutic approaches and the current status of immunization strategies for CDI, which might help to bridge the knowledge gap in the generation of therapy against CDI.

Clinical outcomes of antimicrobial resistance in cancer patients: a systematic review of multivariable models

BACKGROUND

Infections are major causes of disease in cancer patients and pose a major obstacle to the success of cancer care. The global rise of antimicrobial resistance threatens to make these obstacles even greater and hinder continuing progress in cancer care. To prevent and handle such infections, better models of clinical outcomes building on current knowledge are needed. This internally funded systematic review (PROSPERO registration: CRD42021282769) aimed to review multivariable models of resistant infections/colonisations and corresponding mortality, what risk factors have been investigated, and with what methodological approaches.

METHODS

We employed two broad searches of antimicrobial resistance in cancer patients, using terms associated with antimicrobial resistance, in MEDLINE and Embase through Ovid, in addition to Cinahl through EBSCOhost and Web of Science Core Collection. Primary, observational studies in English from January 2015 to November 2021 on human cancer patients that explicitly modelled infection/colonisation or mortality associated with antimicrobial resistance in a multivariable model were included. We extracted data on the study populations and their malignancies, risk factors, microbial aetiology, and methods for variable selection, and assessed the risk of bias using the NHLBI Study Quality Assessment Tools.

RESULTS

Two searches yielded a total of 27,151 unique records, of which 144 studies were included after screening and reading. Of the outcomes studied, mortality was the most common (68/144, 47%). Forty-five per cent (65/144) of the studies focused on haemato-oncological patients, and 27% (39/144) studied several bacteria or fungi. Studies included a median of 200 patients and 46 events. One-hundred-and-three (72%) studies used a p-value-based variable selection. Studies included a median of seven variables in the final (and largest) model, which yielded a median of 7 events per variable. An in-depth example of vancomycin-resistant enterococci was reported.

CONCLUSIONS

We found the current research to be heterogeneous in the approaches to studying this topic. Methodological choices resulting in very diverse models made it difficult or even impossible to draw statistical inferences and summarise what risk factors were of clinical relevance. The development and adherence to more standardised protocols that build on existing literature are urgent.

The burden of Clostridioides difficile on COVID-19 hospitalizations in the USA

BACKGROUND AND AIM

Clostridioides difficile infection (CDI) is the leading cause of hospital acquired-infectious diarrhea in the USA. In this study, we assess the prevalence and impact of CDI in COVID-19 hospitalizations in the USA.

METHODS

We used the 2020 National Inpatient Sample database to identify adult patients with COVID-19. The patients were stratified into two groups based on the presence of CDI. The impact of CDI on outcomes such as in-hospital mortality, ICU admission, shock, acute kidney injury (AKI), and sepsis rates. Multivariate regression analysis was performed to assess the effects of CDI on outcomes.

RESULTS

The study population comprised 1581 585 patients with COVID-19. Among these, 0.65% of people had a CDI. There was a higher incidence of mortality in patients with COVID-19 and CDI compared with patients without COVID-19 (23.25% vs 13.33%, P < 0.001). The patients with COVID-19 and CDI had a higher incidence of sepsis (7.69% vs 5%, P < 0.001), shock (23.59% vs 8.59%, P < 0.001), ICU admission (25.54% vs 12.28%, P < 0.001), and AKI (47.71% vs 28.52%, P < 0.001). On multivariate analysis, patients with CDI had a statistically significant higher risk of mortality than those without (aOR = 1.47, P < 0.001). We also noted a statistically significant higher risk of sepsis (aOR = 1.47, P < 0.001), shock (aOR = 2.7, P < 0.001), AKI (aOR = 1.55, P < 0.001), and ICU admission (aOR = 2.16, P < 0.001) in the study population.

CONCLUSIONS

Our study revealed the prevalence of CDI in COVID-19 patients was 0.65%. Although the prevalence was low, its presence is associated with worse outcomes and higher resource utilization.

Outcomes of Clostridioides difficile infection in adult cancer and non-cancer patients hospitalised in a tertiary hospital: a prospective cohort study

BACKGROUND

Clostridioides difficile infection (CDI) is one of the most common healthcare-associated (HA) infections. Cancer patients, particularly haemato-oncological patients, have an increased risk for CDI due to more risk factors compared with non-cancer patients. The aim of this study was to investigate differences in outcomes associated with HA CDI in patients with solid and haematological malignancies compared with patients with no underlying malignant disease in a tertiary healthcare centre in Serbia.

METHODS

A prospective cohort study was conducted including adult patients diagnosed with an initial episode of HA CDI. Their demographic and clinical characteristics associated with risk factors for CDI were documented. Outcomes such as all-cause 30-day mortality, cure of infection, diarrhoea relaps and recurrence of disease were followed. Patients were assigned to cancer and non-cancer groups. Within the cancer group, patients were divided into the solid tumour subgroup and haematological malignancy subgroup.

RESULTS

During a 7-year period, HA CDI was observed in 28 (5.1%) patients with haematological malignancy, 101 (18.3%) patients with solid tumours and 424 (76.7%) non-cancer patients. Older age (OR 1.04, 95% CI 1.02 to 1.07, p<0.001), admission to the intensive care unit (ICU) (OR 2.61, 95% CI 1.37 to 4.95, p=0.003), mechanical ventilation (OR 5.19, 95% CI 2.78 to 9.71, p<0.001) and use of antibiotics prior to CDI (OR 1.04, 95% CI 1.02 to 1.06, p=0.02) were associated with increased mortality. Compared with patients with solid tumours, patients with haematological malignancy were younger (65 vs 57 years, p=0.015), did not require ICU admission (25.0% vs 0%) or mechanical ventilation (8.9% vs 0%) and were treated longer with antibiotics prior to CDI (14 vs 24 days, p=0.002).

CONCLUSIONS

Patients with haematological malignancy were exposed to different risk factors for CDI associated with mortality compared with patients with solid tumours and non-cancer patients. Older age, ICU stay and mechanical ventilation, but not presence or type of cancer, predicted the all-cause 30-day mortality.

Early Antibiotic Discontinuation or De-escalation in High-Risk Patients With AML With Febrile Neutropenia and Prolonged Neutropenia

BACKGROUND

There is minimal data evaluating the safety of antibiotic de-escalation in patients with acute myeloid leukemia (AML) with fever and ongoing neutropenia. Therefore, this study evaluated antibiotic prescribing, infection-related outcomes, and patient outcomes of an antibiotic de-escalation initiative.

PATIENTS AND METHODS

This pre-post quasiexperimental study included adult patients with AML hospitalized with febrile neutropenia. An antibiotic de-escalation guideline was implemented in January 2017, which promoted de-escalation or discontinuation of intravenous antipseudomonal β-lactams. The primary outcome assessment was the incidence of bacterial infection in a historical control group before guideline implementation compared with an intervention group after guideline implementation.

RESULTS

A total of 93 patients were included. Antibiotic de-escalation occurred more frequently in the intervention group (71.7% vs 7.5%; P<.001), which resulted in fewer days of therapy for intravenous antipseudomonal β-lactams (14 vs 25 days; P<.001). Thirty-day all-cause mortality and length of hospitalization were not different between groups. However, the intervention group had significantly fewer episodes of Clostridioides difficile colitis (5.7% vs 27.5%; P=.007).

CONCLUSIONS

Implementation of an antibiotic de-escalation guideline resulted in decreased use of intravenous antipseudomonal β-lactams and fewer episodes of C difficile colitis, without adversely impacting patient outcomes. Additional studies are needed, preferably in the form of randomized controlled trials, to confirm these results.

Host Immune Responses to Clostridioides difficile: Toxins and Beyond

Clostridioides difficile is often resistant to the actions of antibiotics to treat other bacterial infections and the resulting C. difficile infection (CDI) is among the leading causes of nosocomial infectious diarrhea worldwide. The primary virulence mechanism contributing to CDI is the production of toxins. Treatment failures and recurrence of CDI have urged the medical community to search for novel treatment options. Strains that do not produce toxins, so called non-toxigenic C. difficile, have been known to colonize the colon and protect the host against CDI. In this review, a comprehensive description and comparison of the immune responses to toxigenic C. difficile and non-toxigenic adherence, and colonization factors, here called non-toxin proteins, is provided. This revealed a number of similarities between the host immune responses to toxigenic C. difficile and non-toxin proteins, such as the influx of granulocytes and the type of T-cell response. Differences may reflect genuine variation between the responses to toxigenic or non-toxigenic C. difficile or gaps in the current knowledge with respect to the immune response toward non-toxigenic C. difficile. Toxin-based and non-toxin-based immunization studies have been evaluated to further explore the role of B cells and reveal that plasma cells are important in protection against CDI. Since the success of toxin-based interventions in humans to date is limited, it is vital that future research will focus on the immune responses to non-toxin proteins and in particular non-toxigenic strains.

Antimicrobial therapy during cancer treatment: Beyond antibacterial effects

Cancer treatment options have evolved to include immunotherapy and targeted therapy, in addition to traditional chemoradiation. Chemoradiation places the patient at a higher risk of infection through a myelosuppressive effect. High clinical suspicion and early use of antimicrobials play a major role in decreasing any associated morbidity and mortality. This has led to a widespread use of antimicrobials in cancer patients. Antimicrobial use, however, does not come without its perils. Dysbiosis caused by antimicrobial use affects responses to chemotherapeutic agents and is prognostic in the development and severity of certain cancer treatment-related complications such as graft-versus-host disease and Clostridioides difficile infections. Studies have also demonstrated that an intact gut microbiota is essential in the anticancer immune response. Antimicrobial use can therefore modulate responses and outcomes with immunotherapy targeting immune checkpoints. In this review, we highlight the perils associated with antimicrobial use during cancer therapy and the importance of a more judicious approach. We discuss the nature of the pathologic changes in the gut microbiota resulting from antimicrobial use. We explore the effect these changes have on responses and outcomes to different cancer treatment modalities including chemotherapy and immunotherapy, as well as potential adverse clinical consequences in the setting of stem cell transplant.

Clostridioides difficile infection in patients with hematological malignancy: A multicenter study in Taiwan

BACKGROUND

Among the individuals with hematological malignancy (HM) complicated with Clostridioides difficile infection (CDI), the variables associated with in-hospital mortality and recurrence of CDI were investigated.

MATERIAL AND METHODS

Including adults with HM and those without malignancy suffering from CDI from January 2015 to December 2016 in three hospitals in Taiwan.

RESULTS

Totally 314 patients including 77 with HM and 237 patients without malignancy were included. HM patients more often had low leukocyte counts (<500 cells/mL: 28.6% vs. 2.1%) than those without malignancy and more patients without malignancy had severe CDI than patients with HM (31.6% vs. 14.3%, P = .003), according to the severity score of IDSA/SHEA. Patients with HM had a higher recurrence rate of CDI (14.3%, 11/77 vs. 7.2%, 17/237; P = .07) and longer hospital stay (47.2 ± 40.8 days vs. 33.3 ± 37.3 days; P = .006) than those without malignancy. In the multivariate analyses for those with HM and CDI, the in-hospital mortality was associated with vancomycin-resistant Enterococcus (VRE) colonization or infection (odds ratio [OR] 7.72; P = .01), and C. difficile ribotype 078 complex infection (OR 9.22; P = .03). Moreover underlying hematological malignancy (OR 2.74; P = .04) and VRE colonization/infection (OR 2.71; P = .02) were independently associated with CDI recurrence.

CONCLUSION

Patients with HM complicated with CDI were often regarded as non-severe infection, but had a similar in-hospital mortality rate as those without malignancy. CDI due to ribotype 078 complex isolates heralded a poor prognosis among HM patients.

Teaching old mice new tricks: the utility of aged mouse models of C. difficile infection to study pathogenesis and rejuvenate immune response

BACKGROUND

Clostridioides difficile is a serious problem for the aging population. Aged mouse model of C. difficile infection (CDI) has emerged as a valuable tool to evaluate the mechanism of aging in CDI.

METHODS

We reviewed five published studies utilizing aged mice (7-28 months) for CDI model for findings that may advance our understanding of how aging influences outcome from CDI.

RESULTS

Aged mouse models of CDI uniformly demonstrated more severe disease in the old compared to young mice. Diminished neutrophil recruitment to intestinal tissue in aged mice is the most consistent finding. Differences in innate and humoral immune responses were also observed. The effects of aging on the outcome of infection were reversed by pharmacologic or microbiota-targeted interventions.

CONCLUSION

The aged mouse presents an important in vivo model to study CDI and elucidate the mechanisms underlying advanced age as an important risk factor for severe disease.

Use of carbapenems and glycopeptides increases risk for Clostridioides difficile infections in acute myeloid leukemia patients undergoing intensive induction chemotherapy

Patients with acute myeloid leukemia (AML) are often exposed to broad-spectrum antibiotics and thus at high risk of Clostridioides difficile infections (CDI). As bacterial infections are a common cause for treatment-related mortality in these patients, we conducted a retrospective study to analyze the incidence of CDI and to evaluate risk factors for CDI in a large uniformly treated AML cohort. A total of 415 AML patients undergoing intensive induction chemotherapy between 2007 and 2019 were included in this retrospective analysis. Patients presenting with diarrhea and positive stool testing for toxin-producing Clostridioides difficile were defined to have CDI. CDI was diagnosed in 37 (8.9%) of 415 AML patients with decreasing CDI rates between 2013 and 2019 versus 2007 to 2012. Days with fever, exposition to carbapenems, and glycopeptides were significantly associated with CDI in AML patients. Clinical endpoints such as length of hospital stay, admission to ICU, response rates, and survival were not adversely affected. We identified febrile episodes and exposition to carbapenems and glycopeptides as risk factors for CDI in AML patients undergoing induction chemotherapy, thereby highlighting the importance of interdisciplinary antibiotic stewardship programs guiding treatment strategies in AML patients with infectious complications to carefully balance risks and benefits of anti-infective agents.

The adaptive immune response to Clostridioides difficile: A tricky balance between immunoprotection and immunopathogenesis

Clostridioides difficile (C. difficile) is the major cause of hospital-acquired gastrointestinal infections in individuals following antibiotics treatment. The pathogenesis of C. difficile infection (CDI) is mediated mainly by the production of toxins that induce tissue damage and host inflammatory responses. While innate immunity is well characterized in human and animal models of CDI, adaptive immune responses remain poorly understood. In this review, the current understanding of adaptive immunity is summarized and its influence on pathogenesis and disease outcome is discussed. The perspectives on what we believe to be the main pending questions and the focus of future research are also provided. There is no doubt that the innate immune response provides a first line of defense to CDI. But, is the adaptive immune response a friend or a foe? Probably it depends on the course of the disease. Adaptive immunity is essential for pathogen eradication, but may also trigger uncontrolled or pathological inflammation. Most of the understanding of the role of T cells is based on findings from experimental models. While they are a very valuable tool for research studies, more studies in human are needed to translate these findings into human disease. Another main challenge is to unravel the role of the different T cell populations on protection or induction of immunopathogenesis.

Clostridioides difficile Infections in Inpatient Pediatric Oncology Patients: A Cohort Study Evaluating Risk Factors and Associated Outcomes

BACKGROUND

Clostridioides difficile infection (CDI) is a significant source of morbidity in pediatric cancer patients. Few reports to date have evaluated risk factors and short-term outcomes for this population.

METHODS

We retrospectively evaluated pediatric oncology admissions at St Louis Children's Hospital from 2009 to 2018. All inpatient cases of diagnosed initial CDI were identified. We aimed to investigate the prevalence of CDI and associated risk factors, including coadmission with another patient with CDI, and to evaluate short-term outcomes including length of stay and delays in subsequent scheduled chemotherapy.

RESULTS

Review of 6567 admissions from 952 patients revealed 109 CDI cases (11.4% of patients). Patients with leukemia or lymphoma, compared to those with solid tumors, were more likely to have CDI (odds ratio [OR], 3 [95% CI, 1.4-6.6], and 3 [95% CI, 1.3-6.8], respectively). Autologous hematopoietic stem cell transplant (HSCT) was also a risk factor (OR, 3.5 [95% CI, 1.7-7.4]). Prior antibiotic exposure independently increased the risk for CDI (OR, 3.0 [95% CI, 1.8-4.8]). Concurrent admission with another patient with CDI also significantly increased the risk (OR, 84.7 [95% CI, 10.5-681.8]). In contrast to previous reports, exposure to acid-suppressing medications decreased the risk for CDI (OR, 0.5 [95% CI, .3-.7]). CDI was associated with increased length of stay (mean difference, 8 days [95% CI, 4.6-11.4]) and prolonged delays for subsequent chemotherapy (mean difference, 1.4 days [95% CI, .1-2.7]).

CONCLUSIONS

CDI in pediatric oncology patients significantly prolongs hospitalization and delays chemotherapy treatment plans. Interventions to control CDI will improve the care of pediatric oncology patients.

The economic burden of Clostridioides difficile infection in patients with hematological malignancies in the United States: A case-control study

OBJECTIVE

The primary study aim was to describe all direct healthcare costs associated with Clostridioides difficile infection (CDI), both in and out of the hospital, in patients with hematologic malignancies in the United States.

DESIGN

A retrospective analysis was conducted utilizing data from US databases of Truven Health Analytics.

PATIENTS

We analyzed health insurance claims between January 2014 and December 2017 of patients diagnosed with hematological cancer: acute myeloid leukemia (AML), acute lymphoblastic leukemia, Hodgkin's lymphoma, and non-Hodgkin's lymphoma (NHL).

METHODS

Patients with CDI after cancer diagnosis (CDI+, cases) were matched with patients without CDI reported (CDI-, controls). Matched cases and controls were compared to identify the CDI-associated costs in the 90 days following the onset of CDI.

RESULTS

We matched 622 CDI+ patients with 11,111 CDI- patients. NHL (41.7%) and AML (30.9%) were the predominant underlying diseases in the CDI+ groups. During study period, the average time in-hospital of CDI+ patients was 23.1 days longer than for CDI- patients (P < 2×10-16). Overall, CDI onset increased costs of care by an average of US$57,159 per patient (P = 6×10-12), mainly driven by hospital costs.

CONCLUSIONS

This study confirms the significant economic burden associated with CDI in the United States, especially in patients with hematological malignancies. These findings highlight the need for prevention of CDI in this specific patient population.

Incidence and Outcomes Associated With Clostridium difficile Infections: A Systematic Review and Meta-analysis

IMPORTANCE

An understanding of the incidence and outcomes of Clostridium difficile infection (CDI) in the United States can inform investments in prevention and treatment interventions.

OBJECTIVE

To quantify the incidence of CDI and its associated hospital length of stay (LOS) in the United States using a systematic literature review and meta-analysis.

DATA SOURCES

MEDLINE via Ovid, Cochrane Library Databases via Wiley, Cumulative Index of Nursing and Allied Health Complete via EBSCO Information Services, Scopus, and Web of Science were searched for studies published in the United States between 2000 and 2019 that evaluated CDI and its associated LOS.

STUDY SELECTION

Incidence data were collected only from multicenter studies that had at least 5 sites. The LOS studies were included only if they assessed postinfection LOS or used methods accounting for time to infection using a multistate model or compared propensity score-matched patients with CDI with control patients without CDI. Long-term-care facility studies were excluded. Of the 119 full-text articles, 86 studies (72.3%) met the selection criteria.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers performed the data abstraction and quality assessment. Incidence data were pooled only when the denominators used the same units (eg, patient-days). These data were pooled by summing the number of hospital-onset CDI incident cases and the denominators across studies. Random-effects models were used to obtain pooled mean differences. Heterogeneity was assessed using the I2 value. Data analysis was performed in February 2019.

MAIN OUTCOMES AND MEASURES

Incidence of CDI and CDI-associated hospital LOS in the United States.

RESULTS

When the 13 studies that evaluated incidence data in patient-days due to hospital-onset CDI were pooled, the CDI incidence rate was 8.3 cases per 10 000 patient-days. Among propensity score-matched studies (16 of 20 studies), the CDI-associated mean difference in LOS (in days) between patients with and without CDI varied from 3.0 days (95% CI, 1.44-4.63 days) to 21.6 days (95% CI, 19.29-23.90 days).

CONCLUSIONS AND RELEVANCE

Pooled estimates from currently available literature suggest that CDI is associated with a large burden on the health care system. However, these estimates should be interpreted with caution because higher-quality studies should be completed to guide future evaluations of CDI prevention and treatment interventions.

Febrile Neutropenia in Acute Leukemia. Epidemiology, Etiology, Pathophysiology and Treatment

Acute leukemias are a group of aggressive malignant diseases associated with a high degree of morbidity and mortality. An important cause of both the latter is infectious complications. Patients with acute leukemia are highly susceptible to infectious diseases due to factors related to the disease itself, factors attributed to treatment, and specific individual risk factors in each patient. Patients with chemotherapy-induced neutropenia are at particularly high risk, and microbiological agents include viral, bacterial, and fungal agents. The etiology is often unknown in infectious complications, although adequate patient evaluation and sampling have diagnostic, prognostic and treatment-related consequences. Bacterial infections include a wide range of potential microbes, both Gram-negative and Gram-positive species, while fungal infections include both mold and yeast. A recurring problem is increasing resistance to antimicrobial agents, and in particular, this applies to extended-spectrum beta-lactamase resistance (ESBL), Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE) and even carbapenemase-producing Enterobacteriaceae (CPE). International guidelines for the treatment of sepsis in leukemia patients include the use of broad-spectrum Pseudomonas-acting antibiotics. However, one should implant the knowledge of local microbiological epidemiology and resistance conditions in treatment decisions. In this review, we discuss infectious diseases in acute leukemia with a major focus on febrile neutropenia and sepsis, and we problematize the diagnostic, prognostic, and therapeutic aspects of infectious complications in this patient group. Meticulously and thorough clinical and radiological examination combined with adequate microbiology samples are cornerstones of the examination. Diagnostic and prognostic evaluation includes patient review according to the multinational association for supportive care in cancer (MASCC) and sequential organ failure assessment (SOFA) scoring system. Antimicrobial treatments for important etiological agents are presented. The main challenge for reducing the spread of resistant microbes is to avoid unnecessary antibiotic treatment, but without giving to narrow treatment to the febrile neutropenic patient that reduce the prognosis.

Type 3 Immunity during Clostridioides difficile Infection: Too Much of a Good Thing?

Clostridioides (formerly known as Clostridium) difficile is the leading cause of hospital-acquired gastrointestinal infections in the United States and one of three urgent health care threats identified by the Centers for Disease Control and Prevention. C. difficile disease is mediated by the production of toxins that disrupt the epithelial barrier and cause a robust host inflammatory response. Studies in humans as well as animal models of disease have shown that the type of immune response generated against the infection dictates the outcome of disease, often irrespective of bacterial burden. Much of the focus on immunity during C. difficile infection (CDI) has been on type 3 immunity because of the established role for this arm of the immune system in other gastrointestinal inflammatory conditions such as inflammatory bowel disease (IBD). For example, interleukin-22 (IL-22) production by group 3 innate lymphoid cells (ILC3s) protects against pathobionts translocating across the epithelium during CDI. On the other hand, interleukin-17 (IL-17) production by Th17 cells increases CDI-associated mortality. Additionally, neutropenia has been associated with increased susceptibility to CDI in humans, but increased neutrophilia in mouse models correlates with host pathology. Taking the data together, these findings suggest dual roles for type 3 immune responses during infection. Here, we review the complex role of type 3 immunity during CDI and delineate what is known about innate and adaptive cellular immunity as well as the downstream effector cytokines known to be important during this infection.

Clostridioides difficile infection: Incidence and risk factors in a tertiary care facility in Riyadh, Saudi Arabia

BACKGROUND

Significant increase in rates of Clostridioides difficile associated diarrhea (CDI) has been reported globally but there remains a paucity of data from Saudi Arabia.

METHODOLOGY

Prospective hospital-based surveillance for CDI using the Center for Disease Control (CDC) criteria was conducted from June to November 2015 in a tertiary healthcare facility in Riyadh, Saudi Arabia.

RESULTS

During the surveillance period, 106 episodes of CDI were identified among 59 patients in 137,230 patient-days. The incidence of CDI was 3.5 per 10,000 patient days. Of the 106 episodes, 58% (n=61) were new cases, 12% (n=13) were recurrent cases and 30% (n=32) were duplicate cases. Majority of the new cases (n/N=43/61; 70%) were healthcare onset, followed by community onset (21%) and 8% were community-onset healthcare associated. No statistically significant change in trend was observed during the surveillance period. The most prevalent CDI risk factor was use of proton pump inhibitor (PPI) (92%) followed by prolonged use of antibiotics (77%). Pareto-analysis indicated that controlling for PPI use, prolong and multiple antibiotic exposure and prolonged hospitalization results in 80% CDI reduction.

CONCLUSION

The findings indicate a low incidence of CDI. Multicenter studies are needed to elucidate the burden to CDI in the country.

Enterotoxic Clostridia: Clostridioides difficile Infections

Clostridioides difficile is a Gram-positive, anaerobic, spore forming pathogen of both humans and animals and is the most common identifiable infectious agent of nosocomial antibiotic-associated diarrhea. Infection can occur following the ingestion and germination of spores, often concurrently with a disruption to the gastrointestinal microbiota, with the resulting disease presenting as a spectrum, ranging from mild and self-limiting diarrhea to severe diarrhea that may progress to life-threating syndromes that include toxic megacolon and pseudomembranous colitis. Disease is induced through the activity of the C. difficile toxins TcdA and TcdB, both of which disrupt the Rho family of GTPases in host cells, causing cell rounding and death and leading to fluid loss and diarrhea. These toxins, despite their functional and structural similarity, do not contribute to disease equally. C. difficile infection (CDI) is made more complex by a high level of strain diversity and the emergence of epidemic strains, including ribotype 027-strains which induce more severe disease in patients. With the changing epidemiology of CDI, our understanding of C. difficile disease, diagnosis, and pathogenesis continues to evolve. This article provides an overview of the current diagnostic tests available for CDI, strain typing, the major toxins C. difficile produces and their mode of action, the host immune response to each toxin and during infection, animal models of disease, and the current treatment and prevention strategies for CDI.

Pancreatic disease patients are at higher risk for Clostridium difficile infection compared to those with other co-morbidities

Background

Surveillance of Clostridium difficile infection (CDI) in patients with underlying diseases is important because use of prophylactic antibiotics makes them prone to CDI. Epidemiology of CDI in this high-risk population is poorly understood. A study was conducted to evaluate the impact of CDI in patients with specific underlying co-morbidities.

Method

A total of 2036 patients, whose fecal samples were processed for C. difficile toxin A and B assay by ELISA formed the basis of study. Patients with underlying diseases were classified based on the organ/kind of disease as pancreatic (n = 340), renal (n = 408), hepatic (n = 245), malignant (n = 517) and miscellaneous disease (n = 526). Laboratory records of clinical and demographic details were reviewed. The association of CDI with age, gender, antibiotic receipt, clinical symptoms and underlying co-morbidities was analyzed. Variation in CDI cases based on age groups was also investigated.

Result

Clostridium difficile toxin positivity was 21.6% in general, whereas it was 30.6% in the pancreatic, 17.9% in the renal, 19.6%, in the hepatic, 21.3% in the malignancy and 20.0% in the miscellaneous disease groups. Toxin positivity was the lowest (14.8%) for female gender under renal disease and the highest (31.8%) for patients aged 40 to < 60 years, under pancreatic disease. Bloody diarrhea was a significant predictor for C. difficile toxin positivity. C. difficile toxin status irrespective to the underlying diseases was neither dependent on gender, age-groups or the number of antibiotics used. Association between patients’ gender, age and antibiotics receipt with underlying disease conditions, respective to C. difficile toxin status showed significance in relation to male gender (p < 0.05), age 40 to < 60 years (p = 0.03) and those receiving single (p = 0.09) or multiple antibiotics (p = 0.07).

Conclusion

Pancreatic disease patients are at a higher risk for developing CDI, and particularly male gender, age 40 to < 60 years and those receiving antibiotics are at significant risk.

Risk, Outcomes, and Trends of Clostridium Difficile Infection in Multiple Myeloma Patients from a Nationwide Analysis

Background: Patients hospitalized with hematologic malignancy are particularly vulnerable to infection. We sought to determine the risk of Clostridium difficile infection (CDI) in hospitalization with multiple myeloma (MM), as well as its outcomes and trends, using a nationally representative database.

Methods: The Nationwide Inpatient Sample (NIS) from January 2010 to September 2015 was used for this study. We identified all patients aged 18 years or older with a diagnosis of MM using the International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) codes. We identified trends in the annual rates of CDI in MM using negative binomial regressions with robust error variance. We conducted multivariate logistic regression to determine the incidence and the associated risk factors of CDI in MM and compared the outcomes between those with and without CDI using the propensity score method inverse probability weighting to adjust for baseline covariates.

Results: In our cohort study of 114,249 MM patients, 45.96% were females and 54.04% were males. CDI was present in 3.1% of the MM patients. The number of CDI cases increased over the study period with an average rate of 3.27% per year. The mortality rate decreased over the same period with an average rate of 10% decrease per year. Hematopoietic stem cell transplantation (HSCT), neutropenia, inflammatory disease, atrial fibrillation (AF), and chronic kidney disease (CKD) were significant associated risk factors of CDI in MM patients. After adjusting for covariates, patients with CDI had a prolonged hospital stay, inpatient mortality, and significantly increased odds of acute kidney injury (AKI) and AKI requiring hemodialysis, along with higher healthcare resources utilization with significantly higher hospital costs.

Conclusion: MM patients with CDI have significantly increased odds of inpatient mortality, AKI, and AKI requiring hemodialysis. They also have increased healthcare resource utilization compared with those without CDI. Despite the increased rate of the CDI over the years, the mortality rate is going down.

Risk, Outcomes, and Predictors of Clostridium difficile Infection in Lymphoma: A Nationwide Study

OBJECTIVE

The risk of Clostridium difficile infection (CDI) has not been well studied in patients with lymphoma. We thus sought to determine the risk of CDI in hospitalizations with lymphoma along with its trend, outcomes, and predictors using a large database.

METHODS

Hospital discharge data from the Nationwide Inpatient Sample (NIS) from 2007 to 2011 were used for the study. Using the International Classification of Diseases, Ninth Revision, Clinical Modification codes, all adult patients aged 18 years or older having a primary diagnosis of lymphoma were queried for the presence of CDI as any of the secondary diagnoses. The risk of CDI in lymphoma and its yearly trend were assessed. We performed multivariate logistic regression to determine the independent risk factors of CDI in lymphoma. Furthermore, we studied mortality and other adverse outcomes of CDI in patients with lymphoma.

RESULTS

There were 236,312 discharges (weighted) with the primary diagnosis of lymphoma. CDI was present in 2.13% of patients with lymphoma versus 0.8% in the nonlymphoma group (P < 0.001). On multivariate analysis, the significant predictors of CDI in lymphoma were presence of infection (odds ratio [OR] 3.1, 95% confidence interval [CI] 2.7-3.6), stem cell transplant (OR 2.7, 95% CI 2.3-3.4), graft-versus-host disease (OR 1.9, 95% CI 1.4-2.8), race (Asian vs white, OR 1.6, 95% CI 1.1-2.4), chemotherapy (OR 1.6, 95% CI 1.4-1.8), gastrointestinal surgery (OR 1.4, 95% CI 1.2-1.7), and Charlson Comorbidity Index (CCI) (CCI of 2 vs 0-1: OR 1.2, 95% CI 1.1-1.4; CCI of 3 vs 0-1: OR 1.3, 95% CI 1.03-1.6). CDI in lymphoma was associated with worse hospital outcomes such as increased mortality (17% vs 8%), increased length of stay (23.6 vs 9.9 days), mean total hospital charges ($197,015 vs $79,392), rate of intubation (13% vs 4% vs 13%), and rate of total parenteral nutrition (11% vs 3%).

CONCLUSIONS

Hospitalization with lymphoma was associated with an increased risk of CDI. The significant predictors for CDI in lymphoma were infection, stem cell transplant, graft-versus-host disease, race, chemotherapy, gastrointestinal surgery, and Charlson Comorbidity Index. CDI in lymphoma was associated with increased mortality and other adverse outcomes warranting a need of more vigilance for CDI in patients with lymphoma.

Clostridioides difficile colonization and infection in patients with newly diagnosed acute leukemia: Incidence, risk factors, and patient outcomes

BACKGROUND

The frequency, risk factors, and outcomes for Clostridioides difficile infection (CDI) in patients with newly diagnosed acute leukemia (AL) admitted for induction therapy are unclear.

METHODS

We studied 509 consecutive patients with AL admitted between 2006 and 2017 and conducted a prospective C difficile surveillance and ribotyping analysis in a subset of these.

RESULTS

The incidence of CDI was 2.2/1,000 inpatient days during induction, and CDI was rare after discharge. CDI was highest in patients with acute myelogenous leukemia. A hospitalization shortly before admission and administration of a greater number of antibiotics increased the risk for CDI. No single class of antibiotics conveyed an increased risk. All cases were successfully treated, and CDI was not associated with an increase in length of stay, costs, or mortality. In a subgroup analysis, 16% of patients with acute myelogenous leukemia and 4% with other leukemia types were colonized on admission. Colonization was associated with a higher risk of CDI. Ribotyping of available isolates showed 27 different strain types with 014/020 and 027 being the most frequent.

CONCLUSIONS

The number of antibiotics administered are a major risk factor for CDI in patients with AL. However, CDI appears to have minimal clinical impact in this population.

Epidemiologic characteristics of health care-associated outbreaks and lessons learned from multiple outbreak investigations with a focus on the usefulness of routine molecular analysis

BACKGROUND

Single outbreaks have often been reported in health care settings, but the frequency of outbreaks at a hospital over time has not been described. We examined epidemiologic features of all health care-associated outbreak investigations at an academic hospital during a 5-year period.

METHODS

Health care-associated outbreak investigations at an academic hospital (2012-2016) were retrospectively reviewed through data on comprehensive hospital-wide surveillance and pulsed-field gel electrophoresis (PFGE) analysis.

RESULTS

Fifty-one health care-associated outbreaks (annual range, 8-15), including 26 (51%) outbreaks in intensive care units (ICUs), and 263 infected-colonized patients involved in these outbreaks were identified. The frequency of pathogens varied by affected location, specifically multidrug-resistant organisms (20/26 outbreaks, 77% in ICUs vs 2/25 outbreaks, 8% in non-ICUs; P < .0001) and gastroenteritis because of Clostridium difficile, norovirus, or adenovirus (1/26 outbreaks, 4% in ICUs vs 17/25 outbreaks, 68% in non-ICUs; P < .0001). Outbreaks occurred in approximately one-third of all units (37%) with some repeated instances of the same pathogens. Of 16 outbreaks caused by a bacterial pathogen evaluated by PFGE, 12 (75%) included some indistinguishable strains, suggesting person-to-person transmission or a common source.

CONCLUSIONS

This study demonstrated epidemiologic characteristics of multiple outbreaks between ICUs and non-ICUs and the value of molecular typing in understanding the epidemiology of health care-associated outbreaks.

Targeting Clostridium difficile Surface Components to Develop Immunotherapeutic Strategies Against Clostridium difficile Infection

New therapies are needed to prevent and treat Clostridium difficile infection and to limit the rise in antibiotic resistance. Besides toxins, several surface components have been characterized as colonization factors and have been shown as immunogenic. This review will focus on passive and active immunization strategies targeting C. difficile surface components to combat C. difficile. Concerning passive immunization, the first strategies used antisera raised against the entire bacterium to prevent infection in the hamster model. Then, surface components such as the flagellin and the S-layer proteins were used for immunization and the passive transfer of antibodies was protective in animal models. Passive immunotherapy with polyvalent immunoglobulins was used in humans and bovine immunoglobulin concentrates were evaluated in clinical trials. Concerning active immunization, vaccine assays targeting surface components were tested mainly in animal models, mouse models of colonization and hamster models of infection. Bacterial extracts, spore proteins and surface components of vegetative cells such as cell wall proteins, flagellar proteins, and polysaccharides were used as vaccine targets. Vaccine assays were performed by parenteral and mucosal routes of immunization. Both gave promising results and pave the way to development of new vaccines.

Leptin receptor q223r polymorphism influences neutrophil mobilization after Clostridium difficile infection

Clostridium difficile is the leading cause of nosocomial infections in the United States. Clinical disease outcomes after C. difficile infection (CDI) are dependent on intensity of host inflammatory responses. Specifically, peak peripheral white blood cell (WBC) count >20 × 10⁹ l^-1 is an indicator of adverse outcomes in CDI patients, and is associated with higher 30-day mortality. We show that homozygosity for a common single nucleotide polymorphism (Q to R mutation in leptin receptor that is present in up to 50% of people), significantly increases the risk of having peak peripheral WBC count >20 × 10⁹ l^-1 (odds ratio=5.41; P=0.0023) in CDI patients. In a murine model of CDI, we demonstrate that mice homozygous for the same single nucleotide polymorphism (RR mice) have more blood and tissue leukocytes (specifically neutrophils), exaggerated tissue inflammation, and higher mortality as compared with control mice, despite similar pathogen burden. Further, we show that neutrophilia in RR mice is mediated by gut microbiota-directed expression of CXC chemokine receptor 2 (CXCR2), which promotes the release of neutrophils from bone marrow reservoir. Overall these studies provide novel mechanistic insights into the role of human genetic polymorphisms and gut microbiota in regulating the fundamental biological process of CDI-induced neutrophilia.

Mometasone furoate inhibits growth of acute leukemia cells in childhood by regulating PI3K signaling pathway

OBJECTIVES

Acute lymphoblastic leukemia (ALL) is the most common cancer before the age of 15 years, seriously endangering the health of children. The main treatment for Childhood ALL was pharmacotherapy. But these drugs have many side effects and some of them could develop drug resistance quickly. Mometasone furoate (MF) is an efficient glucocorticoid for topical treatment of inflammation on the skin, lung and nose.

METHODS

In this study, we investigated whether the MF had effects on ALL cells proliferation and migration.

RESULTS

The CCK-8 proliferation test showed that the cell viability was the lowest at 25 nM MF treatment and the increased OD value was time-dependent. In transwell assay, the number of CCRF-CEM cells was reduced in MF treated group. We found the expression of anti-apoptotic protein bcl-2 decreased the expression of pro-apoptotic protein caspase3 and bax increased in CCRF-CEM cell line treated with MF. The expression of p-AKT, p-mTOR, p70S6 K, vascular endothelial growth factor and CyclinD1 were decreased in MF treated group.

CONCLUSION

This study reveals that MF can inhibit proliferation and invasion/migration and induce apoptosis in Childhood ALL cells, which may be regulated by Phosphatidylinositol 3-kinase signaling pathway. These results suggest MF may be a potential new drug target for clinical ALL treatment.

Characteristics of Clostridium difficile infection in patients hospitalized with myelodysplastic syndrome or acute myelogenous leukemia

AIM

To evaluate factors associated with Clostridium difficile infection (CDI) and outcomes of CDI in the myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) population.

METHODS

After IRB approval, all MDS/AML patients hospitalized at the University of Maryland Greenebaum Comprehensive Cancer Center between August 2011 and December 2013 were identified. Medical charts were reviewed for demographics, clinical information, development of CDI, complications of CDI, and mortality. Patients with CDI, defined as having a positive stool PCR done for clinical suspicion of CDI, were compared to those without CDI in order to identify predictors of disease. A t-test was used for comparison of continuous variables and chi-square or Fisher’s exact tests were used for categorical variables, as appropriate.

RESULTS

Two hundred and twenty-three patients (60.1% male, mean age 61.3 years, 13% MDS, 87% AML) had 594 unique hospitalizations during the study period. Thirty-four patients (15.2%) were diagnosed with CDI. Factors significantly associated with CDI included lower albumin at time of hospitalization (P < 0.0001), prior diagnosis of CDI (P < 0.0001), receipt of cytarabine-based chemotherapy (P = 0.015), total days of neutropenia (P = 0.014), and total days of hospitalization (P = 0.005). Gender (P = 0.10), age (P = 0.77), proton-pump inhibitor use (P = 0.73), receipt of antibiotics (P = 0.66), and receipt of DNA hypomethylating agent-based chemotherapy (P = 0.92) were not significantly associated with CDI.

CONCLUSION

CDI is common in the MDS/AML population. Factors significantly associated with CDI in this population include low albumin, prior CDI, use of cytarabine-based chemotherapy, and prolonged neutropenia. In this study, we have identified a subset of patients in which prophylaxis studies could be targeted.

Impact of the Microbiota on Bacterial Infections during Cancer Treatment

Patients being treated for cancer are at high risk for infectious complications, generally due to colonizing organisms that gain access to sterile sites via disrupted epithelial barriers. There is an emerging understanding that the ability of bacterial pathogens, including multidrug-resistant organisms, to colonize and subsequently infect humans is largely dependent on protective bacterial species present in the microbiome. Thus, herein we review recent studies demonstrating strong correlations between the microbiome of the oncology patient and infections occurring during chemotherapy. An increased knowledge of the interplay between potential pathogens, protective commensals, and the host immune system may facilitate the development of novel biomarkers or therapeutics that could help ameliorate the toll that infections take during the treatment of cancer.

Role of the leukocyte response in normal and immunocompromised host after Clostridium difficile infection

Clostridium difficile is the leading cause of healthcare-associated infections in the United States. Clinically, C. difficile-associated disease can present as asymptomatic colonization, self-limited diarrheal illness or severe colitis (that may result in death). This variability in disease course and outcomes suggests that host factors play an important role as key determinants of disease severity. Currently, there are several scoring indices to estimate severity of C. difficile-associated disease. Leukocytosis and renal failure are considered to be the most important predictors of C. difficile disease severity in hosts with a normal immune system. The degree of leukocytosis which is considered significant for severe disease and how it is scored vary amongst scoring indices. None of the scores have been prospectively validated, and while total WBC count is useful to estimate the magnitude of the host response in most patient populations, in immune-compromised patients like those receiving chemotherapy, solid organ transplant patients or hematopoietic stem cell transplants the WBC response can be variable or even absent making this marker of severity difficult to interpret. Other cellular subsets like neutrophils, eosinophils and lymphocytes provide important information about the host immune status and play an important role in the immune response against C. difficile infection. However, under the current scoring systems the role of these cellular subsets have been underestimated and only total white blood cell counts are taken into account. In this review we highlight the role of host leukocyte response to C. difficile challenge in the normal and immunocompromised host, and propose possible ways that would allow for a better representation of the different immune cell subsets (neutrophils, lymphocytes and eosinophils) in the current scoring indices.

[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.

The epidemiology of Clostridium difficile infection in patients with cancer

INTRODUCTION

Clostridium difficile infection (CDI) is a significant cause of healthcare-associated diarrhoea, and the emergence of endemic strains resulting in poorer outcomes is recognised worldwide. Patients with cancer are a specific high-risk group for development of infection. Areas covered: In this review, modifiable and non-modifiable risk factors for CDI in adult patients with haematological malignancy or solid tumours are evaluated. In particular, the contribution of antimicrobial exposure, hospitalisation and gastric acid suppression to risk of CDI are discussed. Recent advances in CDI treatment are outlined, namely faecal microbiota transplantation and fidaxomicin therapy for severe/refractory infection in cancer populations. Outcomes of CDI, including mortality are presented, together with the need for valid severity rating tools customised for cancer populations. Expert commentary: Future areas for research include the prognostic value of C. difficile colonisation in cancer patients and the potential impact of dedicated antimicrobial stewardship programs in reducing the burden of CDI in cancer units.

Clostridium difficile Infections amongst Patients with Haematological Malignancies: A Data Linkage Study

Objectives

Identify risk factors for Clostridium difficile infection (CDI) and assess CDI outcomes among Australian patients with a haematological malignancy.

Methods

A retrospective cohort study involving all patients admitted to hospitals in Western Australia with a haematological malignancy from July 2011 to June 2012. Hospital admission data were linked with all hospital investigated CDI case data. Potential risk factors were assessed by logistic regression. The risk of death within 60 and 90 days of CDI was assessed by Cox Proportional Hazards regression.

Results

There were 2085 patients of whom 65 had at least one CDI. Twenty percent of CDI cases were either community-acquired, indeterminate source or had only single-day admissions in the 28 days prior to CDI. Using logistic regression, having acute lymphocytic leukaemia, neutropenia and having had bacterial pneumonia or another bacterial infection were associated with CDI. CDI was associated with an increased risk of death within 60 and 90 days post CDI, but only two deaths had CDI recorded as an antecedent factor. Ribotyping information was available for 33 of the 65 CDIs. There were 19 different ribotypes identified.

Conclusions

Neutropenia was strongly associated with CDI. While having CDI is a risk factor for death, in many cases it may not be a direct contributor to death but may reflect patients having higher morbidity. A wide variety of C. difficile ribotypes were found and community-acquired infection may be under-estimated in these patients.

Neutrophil-mediated inflammation in the pathogenesis of Clostridium difficile infections

Clostridium difficile is the most important cause of nosocomial infectious diarrhea in the western world. C. difficile infections are a major healthcare burden with approximately 500,000 new cases every year and an estimated annual cost of nearly $1 billion in the U.S. Furthermore, the infections are no longer restricted to health care facilities, and recent studies indicate spread of C. difficile infection to the community as well. The clinical spectrum of C. difficile infection ranges from asymptomatic colonization to severe diarrhea, fulminant colitis and death. This spectrum results from a complex interplay between bacterial virulence factors, the colonic microbiome and the host inflammatory response. The overall vigor of host inflammatory response is believed to be an important determinant of C. difficile disease severity, and a more robust immune response is associated with worse outcomes. Neutrophils are the primary cells that respond to C. difficile invasion and neutrophilic inflammation is the hallmark of C. difficile-associated disease. In this review, we will focus on the role of neutrophils (infiltration to infected tissue, pathogen clearance and resolution of inflammation) in the immuno-pathogenesis of C. difficile-associated disease (CDAD).

Clostridium difficile infection in the pediatric transplant patient

CDIs are on the rise in both hospital and community settings in adults and children. Children with cancer or a history of HSCT or SOT appear to be at higher risk for primary disease, recurrent disease, and severe outcomes when compared to children with other comorbidities. The reasons for this are not clear and no studies to date have analyzed risk factors for CDI in pediatric transplant patients. Colonization rates in children with cancer and a transplant history are also high. Determining which children are colonized with Clostridium difficile and symptomatic from another source vs. symptomatic from CDI is difficult and a clinical conundrum for the transplant physician. The use of fecal transplantation for severe or rCDI is likely safe and effective in the immunosuppressed pediatric cancer or transplant patient, but this will need to be more thoroughly studied in this patient population.

Transmission of Clostridium difficile During Hospitalization for Allogeneic Stem Cell Transplant

OBJECTIVE To determine the role of unit-based transmission that accounts for cases of early Clostridium difficile infection (CDI) during hospitalization for allogeneic stem cell transplant. SETTING Stem cell transplant unit at a tertiary care cancer center. METHODS Serially collected stool from patients admitted for transplant was screened for toxigenic C. difficile through the hospital stay and genotyping was performed by multilocus sequence typing. In addition, isolates retrieved from cases of CDI that occurred in other patients hospitalized on the same unit were similarly characterized. Transmission links were established by time-space clustering of cases and carriers of shared toxigenic C. difficile strains. RESULTS During the 27-month period, 1,099 samples from 264 patients were screened, 69 of which had evidence of toxigenic C. difficile; 52 patients developed CDI and 17 were nonsymptomatic carriers. For the 52 cases, 41 had evidence of toxigenic C. difficile on the first study sample obtained within a week of admission, among which 22 were positive within the first 48 hours. A total of 24 sequence types were isolated from this group; 1 patient had infection with the NAP1 strain. A total of 11 patients had microbiologic evidence of acquisition; donor source could be established in half of these cases. CONCLUSIONS Most cases of CDI after stem cell transplant represent delayed onset disease in nonsymptomatic carriers. Transmission on stem cell transplant unit was confirmed in 19% of early CDI cases in our cohort with a probable donor source established in half of the cases.