Impaired gut function as risk factor for invasive candidiasis in neutropenic patients

Increased diversity, fungal burden, and virulence of oral Candida spp. in patients undergoing anti-tuberculosis treatment

Some studies have demonstrated a high prevalence of Candida species in patients with tuberculosis (TB). This is most likely due to long-term antimicrobial therapy. To date, no longitudinal studies addressed the effects of anti-TB treatment on the fungal burden and virulence of Candida spp. This study investigated the prevalence and virulence of Candida spp. in the oral cavity of 30 TB patients at different stages of treatment through a cohort study. These results were compared with those of 60 systemically healthy individuals in a cross-sectional study. Oral rinse samples from TB patients were collected before 45 and after 120 days of treatment. In the control group, the biological samples were collected only once. Candida spp. were identified by restriction fragment length polymorphism (RFLP) assays, and the following virulence factors were studied: phospholipase C and proteinase production, as well as Candida spp. biofilm and hyphae formation. The clinical diagnosis of TB and its treatment time were associated with the greater fungal burden (p < 0.0001), presence of non-albicans Candida (NAC) species (p = 0.0003), and increased virulence factors when compared with the Candida spp. isolated from systemically healthy individuals. The results showed that anti-TB treatment time was responsible for the increased fungal burden and isolation of NAC in TB patients (p = 0.0233). The increased prevalence, quantification, and virulence of Candida spp. isolated from the oral cavity of TB patients highlight the greater risk of oral lesions and cases of systemic dissemination in these patients.

How I perform hematopoietic stem cell transplantation on patients with a history of invasive fungal disease

Hematopoietic transplantation is the preferred treatment for many patients with hematologic malignancies. Some patients may develop invasive fungal diseases (IFDs) during initial chemotherapy, which need to be considered when assessing patients for transplantation and treatment posttransplantation. Given the associated high risk of relapse and mortality in the post-hematopoietic stem cell transplantation (HSCT) period, IFDs, especially invasive mold diseases, were historically considered a contraindication for HSCT. Over the last 3 decades, advances in antifungal drugs and early diagnosis have improved IFD outcomes, and HSCT in patients with a recent IFD has become increasingly common. However, an organized approach for performing transplantation in patients with a prior IFD is scarce, and decisions are highly individualized. Patient-, malignancy-, transplantation procedure-, antifungal treatment-, and fungus-specific issues affect the risk of IFD relapse. Effective surveillance to detect IFD relapse post-HSCT and careful drug selection for antifungal prophylaxis are of paramount importance. Antifungal drugs have their own toxicities and interact with immunosuppressive drugs such as calcineurin inhibitors. Immune adjunct cytokine or cellular therapy and surgery can be considered in selected cases. In this review, we critically evaluate these factors and provide guidance for the complex decision making involved in the peri-HSCT management of these patients.

Evaluation of bioactivities of zinc oxide, cadmium sulfide and cadmium sulfide loaded zinc oxide nanostructured materials prepared by nanosecond pulsed laser

The present study reports the preparation of cadmium sulfide (CdS) loaded zinc oxide (ZnO) nanostructured semiconductor material and its anti-bioactivity studies against cancerous and fungus cells. For composite preparation, two different mass ratios of CdS (10 and 20%) were loaded on ZnO (10%CdS/ZnO, 20%CdS/ZnO) using a 532 nm pulsed laser ablation in water media. The structural and morphological analyses confirmed the successful loading of nanoscaled CdS on the surface of ZnO particles, ZnO particles were largely spherical with average size ~50 nm, while CdS about 12 nm in size. The elemental and electron diffraction analyses reveal that the prepared composite, CdS/ZnO contained both CdS and ZnO, thus reaffirming the production of CdS loaded ZnO. The microscopic examination and MTT assay showed the significant impact of ZnO, CdS, and CdS loaded ZnO on human colorectal carcinoma cells (HCT-116 cells). Our results show that the prepared ZnO had better anticancer activities than individual CdS, and CdS loaded ZnO against cancerous cells. For antifungal efficacy, as-prepared nanomaterials were investigated against Candida albicans by examining minimum inhibitory/fungicidal concentration (MIC/MFC) and morphogenesis. The lowest MIC (0.5 mg/mL), and MFC values (1 mg/mL) were found for 10 and 20%CdS/ZnO. Furthermore, the morphological analyses reveal the severe damage of the cell membrane upon exposure of Candida strains to nanomaterials. The present study suggests that ZnO, CdS, and CdS loaded ZnO nanostructured materials possess potential anti-cancer and anti-fungal activities.

Work-up for Fever During Neutropenia for Both the Stem Cell Transplant Recipient and the Hematologic Malignancy Patient

Fever is a common complication in patients with underlying neutropenia and is associated with significant mortality in neutropenic patients with acute myelogenous leukemia or hematopoietic cell transplant. Fever may be the only sign of infection and requires further clinical assessment, including a history, a physical examination, and additional laboratory and radiographic testing. National and international guidelines recommend initiation of empiric antimicrobial therapy in patients with fever during neutropenia. Stepwise escalation of antibacterial therapy, followed by antifungal therapy for patients with persistent fever, generally is recommended. Consideration should also be given to de-escalation of antimicrobial therapy in the appropriate clinical settings.

Impact of the D-index deduced from duration and intensity of neutropenia following chemotherapy on the risk of invasive fungal infection in pediatric acute myeloid leukemia

Pediatric patients with acute myeloid leukemia (AML) are at high risk of invasive fungal infection (IFI). In adult patients, the D-index, which reflects the duration and intensity of neutropenia, was reported as a predictive factor of IFI after induction therapy for AML. The aim of this study was to assess whether the D-index is a predictive factor for IFI in pediatric AML. We define the D-index as the area over the neutrophil curve during neutropenia. Ninety-two courses of chemotherapy performed for 24 consecutive patients with AML undergoing chemotherapy at Sapporo Hokuyu Hospital between April 2007 and March 2017 were analyzed. We also evaluated the utility of the cumulative D-index (c-D-index) from the start of neutropenia until the clinical manifestation of IFI in these patients. The D-index and c-D-index were compared between courses with and without IFI episodes. The median D-index and c-D-index in 6 courses with IFI episodes were 12,816 (range 9500-27,412) and 7250 (range 3987-16,273), respectively, which was not statistically higher than the median D-index [10,127 (range 3788-20,897)] in 86 courses without IFI episodes (P = 0.081 and P = 0.108, respectively). Unlike in adult cases, neither the D-index nor c-D-index reflected the risk of IFI in pediatric AML.

Fungal colonization of the respiratory tract in allogeneic and autologous hematopoietic stem cell transplant recipients: a study of 573 transplanted patients

Background

Fungal colonization and infections remain a major cause of infection morbidity and mortality following hematopoietic stem cell transplantation (HSCT) in patients with hematological malignancies. The aim of this study was to analyze the spectrum of fungal microflora of the respiratory tract (oral cavity, pharynx, epiglottis, and sputum) in patients undergoing HSCT and to evaluate the relationship between HSCT type and incidence of mycotic colonization and infections.

Material/Methods

Retrospective analysis of fungal isolates collected from the respiratory tract (oral cavity, pharynx, epiglottis, and sputum) of 573 patients undergoing HSCT was performed.

Results

The overall rate of fungal colonization in patients undergoing HSCT was 8.7%. Patients undergoing allogeneic HSCT were statistically significantly more often colonized (12.95%) compared to autologous HSCT recipients (4.7%). Colonizing cultures were mainly C. albicans and C. krusei, and sporadically C. glabrata, C. famata, Aspergillus spp. and Saccharomyces cerevisiae. C. albicans was the most frequent species found in isolates from the pharynx, sputum, and oral cavity collected from patients undergoing HSCT. Aspergillosis was more common after allogeneic than after autologous HSCT. The pharynx was the most frequently colonized site.

Conclusions

Allogeneic HSCT recipients are more susceptible to fungal infections compared to the autologous group. Selection of species during prophylaxis and antifungal therapy requires developing more effective prevention and treatment strategies based on new antifungal drugs and microbe-specific diagnoses.

Inhibitory effect of verapamil on Candida albicans hyphal development, adhesion and gastrointestinal colonization

Candida albicans morphogenesis and gastrointestinal colonization are closely associated with the pathogenicity of this pathogen. This study investigated the in vitro and in vivo effect of verapamil, a calcium channel blocker, on these processes. Exposure to ≥ 10 μg mL(-1) verapamil led to a significant decrease of C. albicans hyphal cells. The ability to adhere to a polystyrene surface and buccal epithelial cells was inhibited by exposure to ≥ 20 μg mL(-1) verapamil. Detection of the Hwp1-green fluorescent protein fusion protein showed that verapamil inhibited expression and transport of Hwp1, indicating its activity against both the regulation network of morphogenesis-associated proteins and the secretory pathway in C. albicans. Moreover, treatment with verapamil at 10 mg (kg day)(-1) led to a remarkable decrease in gastrointestinal-colonizing fungal cells. This study revealed the inhibitory effect of verapamil on C. albicans hyphal development, adhesion and gastrointestinal colonization, which is relevant to decreased expression and abnormal transport of the proteins required for morphogenesis. Therefore, verapamil may be taken into account when choosing an antifungal therapy against C. albicans colonization and infection.

Infection in neutropenic patients with cancer

Neutropenic fever sepsis syndromes are common among patients with cancer who are receiving intensive cytotoxic systemic therapy. Recognition of the syndromes and timely initial antibacterial therapy is critical for survival and treatment success. Outcomes are linked to myeloid reconstitution and recovery from neutropenia, control of active comorbidities, and appropriate treatment of the infections that underlie the sepsis syndrome. Hematologists and oncologists must be clear about the prognosis and treatment goals to work effectively with critical care physicians toward the best outcomes for patients with cancer who develop neutropenic sepsis syndromes.

Canadian clinical practice guidelines for invasive candidiasis in adults

Candidemia and invasive candidiasis (C/IC) are life-threatening opportunistic infections that add excess morbidity, mortality and cost to the management of patients with a range of potentially curable underlying conditions. The Association of Medical Microbiology and Infectious Disease Canada developed evidence-based guidelines for the approach to the diagnosis and management of these infections in the ever-increasing population of at-risk adult patients in the health care system. Over the past few years, a new and broader understanding of the epidemiology and pathogenesis of C/IC has emerged and has been coupled with the availability of new antifungal agents and defined strategies for targeting groups at risk including, but not limited to, acute leukemia patients, hematopoietic stem cell transplants and solid organ transplants, and critical care unit patients. Accordingly, these guidelines have focused on patients at risk for C/IC, and on approaches of prevention, early therapy for suspected but unproven infection, and targeted therapy for probable and proven infection.

Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the infectious diseases society of america

This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia. Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving. What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens. Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care-associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are the universal keys to managing neutropenic patients with fever and/or infection.

Executive Summary: Clinical Practice Guideline for the Use of Antimicrobial Agents in Neutropenic Patients with Cancer: 2010 Update by the Infectious Diseases Society of America

This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia.

Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving.

What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens.

Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care–associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are the universal keys to managing neutropenic patients with fever and/or infection.

What are fungal infections?

Yeasts and moulds now rank amongst the 10 most frequently isolated pathogens in febrile patients with an impaired immune system. Fungi are mainly opportunistic pathogens that only invade the body if a severely weakened natural defense permits them to do so. Most factors facilitating an invasive fungal infection are unavoidable because they are directly connected to the underlying diseases as well as to their treatment.Modern aggressive treatment modalities jeopardize the defense mechanisms to an extent that even fungi with a low virulence may enter the body.

Considerations in the approach to invasive fungal infection in patients with haematological malignancies

Invasive infections because of opportunistic yeasts and moulds have contributed significantly to the morbidity and mortality associated with potentially curative treatment for haematological malignancies. Many risk factors have been identified that permit the clinician to predict the likelihood of these infections. The diagnostic process involves maintaining a high index of suspicion based upon an understanding of the clinical circumstances under which invasive fungal infections occur, of the spectrum of fungal syndromes, and of the advantages and limitations of diagnostic testing strategies now available. Treatment strategies may be categorized as prophylactic, pre-emptive, empiric, or directed based upon the circumstances. The therapeutic options have increased in recent years but are not applicable to all clinical circumstances. These considerations are discussed.

One year prospective survey of Candida bloodstream infections in Scotland

A 12 month survey of candidaemia in Scotland, UK, in which every Scottish hospital laboratory submitted all blood isolates of yeasts for identification, strain typing and susceptibility testing, provided 300 isolates from 242 patients, generating incidence data of 4.8 cases per 100,000 population per year and 5.9 cases per 100,000 acute occupied bed days; 27.9 % of cases occurred in intensive care units. More than half the patients with candidaemia had an underlying disease involving the abdomen, 78 % had an indwelling intravenous catheter, 62 % had suffered a bacterial infection within the 2 weeks prior to candidaemia and 37 % had undergone a laparotomy. Candida albicans was the infecting species in 50 % of cases, followed by Candida glabrata (21 %) and Candida parapsilosis (12 %). Seven cases of candidaemia were caused by Candida dubliniensis, which was more prevalent even than Candida lusitaniae and Candida tropicalis (six cases each). Among C. glabrata isolates, 55 % showed reduced susceptibility to fluconazole, but azole resistance among other species was extremely low. Multilocus sequence typing showed isolates with high similarity came from different hospitals across the country, and many different types came from the hospitals that submitted the most isolates, indicating no tendency towards hospital-specific endemic strains. Multiple isolates of C. albicans and C. glabrata from individual patients were of the same strain type with single exceptions for each species. The high prevalence of candidaemia in Scotland, relative to other population-based European studies, and the high level of reduced fluconazole susceptibility of Scottish C. glabrata isolates warrant continued future surveillance of invasive Candida infections.

Candida glabrata colonizes but does not often disseminate from the mouse caecum

Candida glabrata is the second or third most frequent cause of candidaemia. The gastrointestinal tract is considered to be a major portal of entry for systemic candidiasis, but relatively few studies have investigated the pathogenesis of C. glabrata. Experiments were designed to clarify the ability of C. glabrata to disseminate from the mouse intestinal tract. Following oral inoculation, C. glabrata readily colonized the caeca [approx. 107 cells (g caecum)−1] of antibiotic-treated mice, but extraintestinal dissemination was not detected. Superimposing several mouse models of trauma and/or immunosuppression known to induce dissemination of Candida albicans and other intestinal microbes did not cause C. glabrata to disseminate often, although one exception was mice given high doses of dexamethasone for 4 days. These data support the hypothesis that the antibiotic-treated mouse intestine may be an epidemiological reservoir for C. glabrata and that this yeast tends to disseminate under specific clinical conditions.

Determining mucosal barrier injury to the oesophagus using CT scan

INTRODUCTION

Oral mucositis is recognised as one of the most debilitating complications of high-dose cytostatic chemotherapy used to prepare for haematopoietic stem cell transplantation (HSCT), but very little is known about oesophageal mucositis, as endoscopy is not routinely performed.

MATERIALS AND METHODS

We incorporate the computed tomography (CT) scan in the diagnostic workup of fever during neutropenia to detect evidence of pulmonary complications. This allowed us to evaluate whether mucosal barrier injury to the oesophagus can be determined. We selected 46 patients without oesophageal cancer or immune suppression (controls), who had a normal oesophagus, and measured the mucosal thickness at the upper part (UP), middle part (MP) and lower part (LP) of the oesophagus. Next, we selected 30 patients having a CT scan done for diagnostic purposes within 14 days after HSCT and measured mucosal thickness at the same levels. We also scored oral mucositis and gut toxicity.

RESULTS

The mucosal thickness of the UP, MP and LP, respectively, for the controls (mean +/- SD) was 4.1 mm (+/-1.1), 4.2 mm (+/-1.2) and 4.8 mm (+/-1.3), and the corresponding values for the subjects were 5.9 mm (+/-2.2), 5.9 mm (+/-2.0) and 7.7 mm (+/-3.0). Analysis of variance showed statistically significant differences between subjects and controls at all oesophageal levels. All patients suffered from severe oral mucositis at the time.

CONCLUSION

Hence, mucosal barrier injury to the oesophagus can be objectively measured using CT scan.

Nosocomial fungal infections: epidemiology, diagnosis, and treatment

Invasive fungal infections are increasingly common in the nosocomial setting. Furthermore, because risk factors for these infections continue to increase in frequency, it is likely that nosocomial fungal infections will continue to increase in frequency in the coming decades. The predominant nosocomial fungal pathogens include Candida spp., Aspergillus spp., Mucorales, Fusarium spp., and other molds, including Scedosporium spp. These infections are difficult to diagnose and cause high morbidity and mortality despite antifungal therapy. Early initiation of effective antifungal therapy and reversal of underlying host defects remain the cornerstones of treatment for nosocomial fungal infections. In recent years, new antifungal agents have become available, resulting in a change in standard of care for many of these infections. Nevertheless, the mortality of nosocomial fungal infections remains high, and new therapeutic and preventative strategies are needed.

Increasing fungal infections in the intensive care unit

BACKGROUND

Yeasts and molds now rank among the most common pathogens in intensive care units. Whereas the incidence of Candida infections peaked in the late 1970s, aspergillosis is still increasing.

METHOD

Review of the pertinent English-language literature.

RESULTS

Most factors promoting an invasive fungal infection are difficult to avoid because they are connected directly to treatment of the underlying disease. Antifungal treatment is often commenced on an empiric basis, whereas it might be preferable to adopt a strategy based on a diagnostic procedure able to demonstrate or exclude fungal disease. Polyenes have been the drugs of choice, but voriconazole is the new standard for aspergillosis. For invasive candidiasis, fluconazole is a more convenient option, with the new echinocandins or voriconazole as alternatives.

CONCLUSIONS

The incidence of invasive fungal infection is increasing, but so too are the choices of agents for therapy. For reasons of efficacy and safety, therapy with an echinocandin or azole antifungal agent is supplanting the use of polyenes.

Invasive candidal enterocolitis followed shortly by fatal cerebral hemorrhage in immunocompromised patients

Two immunocompromised adult patients (male, 43 years of age; female, 50 years of age) are described who developed unusual and similarly unique complications. After chemotherapy, both presented with abdominal pain and severe bloody diarrhea. Initial blood cultures were negative, and abdominal CT showed pneumatosis and thickening of colonic wall. Colonoscopy showed severe right-sided colitis. Relentless bloody diarrhea necessitated emergency right hemicolectomy in both cases. Pathologic examination of the specimens showed extensive and severe hematogenous Candida enterocolitis. Both patients died of acute cerebral hemorrhage within 3 days of hemicolectomy. Autopsy, performed on 1 of the 2 cases, showed diffuse severe cerebritis and cerebral hemorrhage secondary to hematogenous invasive candidiasis. This sequence of events is not documented in the English literature on candidal enterocolitis, which is reviewed.

Monitoring myeloablative therapy-induced small bowel toxicity by serum citrulline concentration: a comparison with sugar permeability tests

BACKGROUND

Intestinal mucositis is an important cause of cancer treatment-related morbidity and mortality, carrying a serious economic burden. Currently, objective parameters are lacking that would enable the monitoring of gut damage in routine clinical practice, thus hindering the development of clinical studies designed to investigate potential new strategies aimed at reducing or preventing this side effect. The authors investigated the characteristics of serum citrulline concentration compared with sugar permeability tests with respect to its use as a marker for cancer treatment-induced small bowel injury.

METHODS

In this prospective study, 10 patients with hematologic malignancies who were receiving myeloablative therapy had gut toxicity assessed with sugar permeability tests. Serum citrulline concentrations also were determined using archival serum samples. The association between both parameters and their respective characteristics were analyzed and compared with data from the literature.

RESULTS

Sensitivity and specificity were better for the citrulline assay compared with sugar permeability tests. Maximum gut damage assessed with the citrulline assay was observed 1-2 weeks earlier compared with the sugar permeability test. Similarly, citrulline indicated recovery of gut damage at 3 weeks after transplantation, whereas most sugar permeability tests remained abnormal.

CONCLUSIONS

The simplicity of the method, the low costs, and the lack of drawbacks to the method make the citrulline assay the first choice for measuring and monitoring treatment-related gut damage and provides an objective parameter for cancer treatment-related gut toxicity.

Veno-occlusive disease: cytokines, genetics, and haemostasis

Hepatic veno-occlusive disease (VOD) is a major cause of morbidity and mortality following high dose cytotoxic therapy for stem cell transplantation (SCT). Pre-existing liver damage, SCT-related therapy, and genetic polymorphisms all appear to increase the risk of developing VOD. Studies of biological markers during SCT suggest that cytokines, haemostasis, and hepatic drug metabolism via the glutathione pathway are all involved in the pathogenesis of VOD. Until recently, treatment options were limited and experimental therapies directed at the pathogenesis of the disease were mostly unsuccessful. However, Defibrotide, a relatively new agent that has modulatory effects on vascular endothelium, cytokine release, and haemostasis, has been used with some success in the management and prophylaxis of VOD. In the future, a better understanding of genetic polymorphisms and biological markers which may be important in the pathogenesis of VOD, may enable us to predict which patients are most likely to be affected.