Cryptococcal cellulitis on the shin of an immunosuppressed patient

Cryptococcus neoformans is a common fungus found throughout the environment that causes opportunistic disease in immunocompromised individuals. Infection of humans with C neoformans usually manifests as lung disease through inhalation of spores or meningoencephalitis by involvement of the central nervous system. Rarely, dissemination in the form of cutaneous lesions can occur in individuals with long term immunosuppression. We present a patient with C. neoformans manifesting as cellulitis with focal segmental glomerulosclerosis treated with corticosteroids. Because of the mortality associated with disseminated cryptococcosis, early identification, especially of atypical cutaneous presentations is critical from a dermatological perspective.

Folliculocentric cutaneous presentation of disseminated Candida krusei infection in a patient with acute myeloid leukemia

Candida krusei (C. krusei) is a multidrug-resistant opportunistic fungal pathogen that may cause disseminated infections in immunocompromised hosts. However, its clinical and histologic features are not well-characterized. We present a unique case to contribute to the growing knowledge base associated with this organism. During hospitalization for neutropenic fever, a 19-year-old man with acute myeloid leukemia, who underwent hematopoietic stem cell transplantation, developed a generalized folliculocentric eruption following initiation of antifungal therapy for newly diagnosed C. krusei fungemia. Despite adequate antifungal coverage and negative blood cultures, the follicular-based erythematous papules persisted. Biopsies demonstrated yeast within ruptured follicles, without angiotropism or involvement of the interfollicular dermis, subcutaneous tissue, or stratum corneum. Concurrent skin tissue cultures confirmed C. krusei. The patient remained febrile despite aggressive antifungal therapy, with relapse of leukemia and subsequent death. Our case is unusual given the development of cutaneous lesions following clearance of fungemia, with yeast limited to ruptured follicular lumina, possibly indicating a primary cutaneous source or early transfollicular/transepidermal elimination. Given the limited available descriptions of cutaneous histopathology for C. krusei, we seek to add to the understanding of its pathophysiology and aid in the diagnosis and treatment of this often fatal infection.

Cryptococcus laurentii fungaemia in a cervical cancer patient

Infections caused by emerging Cryptococcus non-neoformans species are being reported with increasingly frequency. Here, we present a case of fungaemia by Cryptococcus laurentii in a woman receiving aggressive immunosuppressive therapy for cervical neoplasia. Three venous blood samples were aseptically collected on consecutive days and C. laurentii was isolated and identified through phenotypic and molecular methods. After central venous catheter removal and appropriate antifungal therapy, the patient showed significant improvement and blood culture became negative. Thus, patients following immunosuppressive therapies and using invasive medical devices are at risk of C. laurentii blood infections.

Rhodotorula fungemia of an intensive care unit patient and review of published cases

Rhodotorula species are commensal yeasts that have emerged as a cause of life-threatening fungemia in severely immunocompromised patients. A case of Rhodotorula mucilaginosa fungemia in a 48-year-old woman that had undergone consecutive abdominal surgeries due to ovarian cancer and bowel necrosis while she was receiving fluconazole prophylaxis is presented. Several risk factors were identified such as presence of central venous catheters, solid organ neoplasm, abdominal surgery and administration of antibiotics. Identification was performed using commercial systems. The yeast was resistant to fluconazole, posaconazole and voriconazole and to echinocandins, whereas MIC to amphotericin B was 1.5 mg/L. Furthermore, published cases of Rhodotorula spp fungemia during the last decade are reviewed. In conclusion, Rhodotorula spp must be considered a potential pathogen in patients with immunosupression and central venous catheters. Correct identification is mandatory for appropriate management, as Rhodotorula spp are resistant to antifungal agents, such as fluconazole and echinocandins.

Fungemia and renal fungus ball formation with Candida norvegensis in a child with acute lymphoblastic leukemia

Invasive fungal infections cause significant morbidity and mortality in pediatric cancer patients. Candida species are the most frequently isolated pathogen. Candida species may cause bloodstream and deep-seated infection in neutropenic children with cancer. The gastrointestinal system, lung, liver and spleen are the most frequently involved organs. Isolated renal involvement presented as abscess formation has been reported rarely in children with cancer. Herein, we report a patient with acute lymphoblastic leukemia (ALL) who presented with renal abscess and fungus ball formation due to Candida norvegensis, which is an unusual cause of infection.

Fusarium infection in lung transplant patients: report of 6 cases and review of the literature

Fusarium is a fungal pathogen of immunosuppressed lung transplant patients associated with a high mortality in those with severe and persistent neutropenia. The principle portal of entry for Fusarium species is the airways, and lung involvement almost always occurs among lung transplant patients with disseminated infection. In these patients, the immunoprotective mechanisms of the transplanted lungs are impaired, and they are, therefore, more vulnerable to Fusarium infection. As a result, fusariosis occurs in up to 32% of lung transplant patients. We studied fusariosis in 6 patients following lung transplantation who were treated at Massachusetts General Hospital during an 8-year period and reviewed 3 published cases in the literature. Cases were identified by the microbiology laboratory and through discharge summaries. Patients presented with dyspnea, fever, nonproductive cough, hemoptysis, and headache. Blood tests showed elevated white blood cell counts with granulocytosis and elevated inflammatory markers. Cultures of Fusarium were isolated from bronchoalveolar lavage, blood, and sputum specimens.Treatments included amphotericin B, liposomal amphotericin B, caspofungin, voriconazole, and posaconazole, either alone or in combination. Lung involvement occurred in all patients with disseminated disease and it was associated with a poor outcome. The mortality rate in this group of patients was high (67%), and of those who survived, 1 patient was treated with a combination of amphotericin B and voriconazole, 1 patient with amphotericin B, and 1 patient with posaconazole. Recommended empirical treatment includes voriconazole, amphotericin B or liposomal amphotericin B first-line, and posaconazole for refractory disease. High-dose amphotericin B is recommended for treatment of most cases of fusariosis. The echinocandins (for example, caspofungin, micafungin, anidulafungin) are generally avoided because Fusarium species have intrinsic resistance to them. Treatment should ideally be based on the Fusarium isolate, susceptibility testing, and host-specific factors. Prognosis of fusariosis in the immunocompromised is directly related to a patient's immune status. Prevention of Fusarium infection is recommended with aerosolized amphotericin B deoxycholate, which also has activity against other important fungi.

Invasive fungal rhinitis caused by Paecilomyces lilacinus infection: Report of a case and a novel treatment

Invasive fungal infections of the sinonasal tract are a rare but known entity in immunocompromised patients. Paecilomyces lilacinus is a nematophagous fungi with septate hyphae that has afflicted humans in multiple forms, causing cutaneous, ocular, and sinonasal infections. Only 4 cases of P lilacinus and 2 cases of Paecilomyces variotii in the sinonasal tract have been reported in the literature. We present a case of invasive fungal rhinitis secondary to P lilacinus infection in an immunocompromised patient. She was managed successfully with a novel treatment: voriconazole and endonasal microdebridement.

Candida krusei fungemia in an immunocompromised patient

Candida krusei is an emerging fungal pathogen found primarily in immunocompromised patients. Intrinsic resistance to fluconazole and decreasing susceptibility to other anti-fungal agents are problematic. When colonization occurs, dissemination may follow rapidly. We present a case of a patient with acute lymphoblastic leukemia who, despite being treated prophylactically with fluconazole, developed disseminated C. krusei.

INFLUENCE OF DEPLETION OF ALVEOLAR MACROPHAGES ON APOPTOSIS INCANDIDA-INDUCED ACUTE LUNG INJURY

Apoptosis plays an important role in acute lung injury (ALI), and alveolar macrophages (AMs) are known to secrete proinflammatory cytokines and promote alveolar inflammation. The authors have previously reported that AMs can be depleted by inhalation of 1 mM 2-chloroadenosine (2-CA). In this study, the authors evaluated the effect of AM depletion by 2-CA inhalation on apoptosis in Candida-induced ALI. The results of in situ terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end-labeling (TUNEL) and immunohistochemical studies and measurement of cytokine levels and caspase 3 activities in lung homogenates indicated that the Fas-FasL system and apoptosis of alveolar epithelial cells are suppressed by depletion of AMs by 2-CA inhalation.

Leukocyte Dectin-1 expression is differentially regulated in fungal versus polymicrobial sepsis

OBJECTIVE

To examine peripheral leukocyte Dectin-1 regulation in clinically relevant models of fungal and polymicrobial sepsis.

DESIGN

Prospective animal study.

SETTING

University medical school research laboratory.

SUBJECTS

Age, weight, and sex matched ICR/HSD mice.

INTERVENTIONS

Mice were infected with Candida albicans (1 x 10, intravenously) or were subjected to cecal ligation and puncture to induce polymicrobial sepsis.

MEASUREMENTS

Blood, spleen, and peritoneal exudate were harvested and leukocytes were isolated. Leukocytes were evaluated for membrane-associated Dectin-1 expression and cell phenotype by flow cytometry.

MAIN RESULTS

In C. albicans infection, Dectin-1-positive blood and splenic leukocytes were increased from 23.5% to 58.9% over the course of infection. The increased percentage of Dectin-1-expressing cells was primarily attributable to neutrophilia. However, the amount of Dectin-1 expressed by blood and splenic neutrophils in C. albicans-infected mice was decreased by a range of 49.0% to 53.3%. C. albicans infection also resulted in an infiltration of Dectin-1-positive macrophages and neutrophils into the kidney. In contrast, polymicrobial sepsis decreased blood leukocyte Dectin-1-expressing cells by up to 51.4%. This reduction was due to a decrease in Dectin-1-positive neutrophils in the periphery. However, the percentage of Dectin-1-expressing cells in the peritoneal cavity increased by 774% with cecal ligation and puncture. Treatment of isolated neutrophils with three soluble glucans, mannan, lipopolysaccharide, or a variety of cytokines revealed that glucans, alone or in combination, were the only treatment that resulted in a decrease in Dectin-1-positive neutrophils.

CONCLUSIONS

We conclude that peripheral leukocyte Dectin-1 expression is differentially regulated in fungal vs. polymicrobial sepsis. These data demonstrate that leukocyte Dectin-1 levels are modulated in response to infections of fungal and nonfungal origin.

Histopathological study on experimental endophthalmitis induced by bloodstream infection with Candida albicans

To investigate the details of the pathophysiology of endogenous fungal endophthalmitis (EFE), we performed sequential histological and ophthalmoscopic examination on a rabbit model comparing immunocompromised EFE developed using a steroid with an immunocompetent one intravenously inoculated with Candida albicans. The ophthalmoscopic examination and histological analysis of the retina in both groups demonstrated that lesions appear on the equator of the eyeball and then spread toward the posterior pole. It has been speculated that, because of the unique innate vasculature system of the equator, there is a sudden, decrease of shear stress in rheologically, resulting in adhesion of yeast cells to the endothelial cells. Histological examination revealed that the degree of polymorphonuclear leukocyte (PMN) infiltration was equivalent in the two groups. However, the appearance of PMN was delayed and the number of fungi was higher in the state of hyphae and/or pseudohyphae in the steroid-treated group. Furthermore, the eyeball was found to be the second earliest organ involved in candidemia. Our results indicate that ophthalmic examination is useful to monitor the development and systemic involvement of endophthalmitis in patients with candidemia.

Utilidad de la detección de (1→3)-ß-D-glucano y anticuerpos anti-micelio de Candida albicans para el diagnóstico y seguimiento terapéutico de la candidiasis invasora en pacientes neutropénicos adultos

The usefulness to diagnose and monitor invasive candidiasis (IC) using beta-glucan (BG) and antibodies against Candida albicans germ tubes (CAGT) was evaluated in a twice-weekly screening of 35 episodes in neutropenic adults at high risk. Three proven IC and three probable IC were assessed. Diagnostic levels of both markers were detected in 100% of proven IC and in 66% of probable IC. Sensitivity, specificity, positive and negative predictive values of BG and anti-CAGT antibodies detection were 83.3%, 89.6%, 62.5% and 96.3%, and 83.3%, 86.2%, 55.5%, 96.1%, respectively. False positive reactions occurred at a rate of 10.3% and 13.8% for the detection of BG and anti-CAGT antibodies, respectively. However, the patients with false positive results were different by each test. Both tests anticipated the clinical and radiological diagnosis, and the initiation of antifungal therapy in most patients. Combination of both tests improved specificity and positive predictive value to 100%.

Systemic and cerebrospinal fluid T-helper cytokine responses in organ transplant recipients with Cryptococcus neoformans infection

BACKGROUND

The role of Th1 and Th2 mediated cytokine responses in the pathogenesis of Cryptococcus neoformans infection in organ transplant recipients has not been defined.

METHODS

We assessed cytokine levels in the sera and CSF collected prospectively at the time of diagnosis of infection in 25 transplant recipients with cryptococcosis. Serum levels were compared with those in healthy individuals and transplant recipients without cryptococcosis. IFN-gamma or IL-12 (Th1)/IL-10 (Th2) ratio < 1.0 was considered a dominant Th2 response.

RESULTS

Cases had lower ratios of IFN-gamma/IL-10 (p = 0.03) and IL-12/IL-10 (p = 0.03) compared to healthy individuals. Cytokine responses, however, did not differ significantly for cases vs. transplant controls. Cases with fungemia compared to those without fungemia tended to have higher serum IL-10 levels (p = 0.07) and lower IL-12/IL-10 ratios (p = 0.06). CSF ratios of IFN-gamma/IL-10 (p = 0.04) and IL-12/IL-10 (p = 0.04) were lower in cases with cryptococcal meningitis compared to those without meningitis; 80% (8/10) of the cases with cryptococcal meningitis vs. 0% (4/4) of those without meningitis had CSF IFN-gamma/IL-10 ratio of < 1.0 (p = 0.015). The levels of IL-10 (p = 0.04) and IFN-gamma (p = 0.04) in the CSF in cases with cryptococcal meningitis were significantly higher than those in their serum, respectively.

CONCLUSIONS

High expression of Th2 phenotype in cryptococcal meningitis and in fungemia suggests that Th dysregulation may contribute to the pathogenesis of cryptococcosis in organ transplant recipients.

Effectiveness of bombesin and Saccharomyces boulardii against the translocation of Candida albicans in the digestive tract in immunosuppressed rats

PURPOSE

We investigated the effects of bombesin on disseminated candidiasis, and compared the effectiveness of bombesin with Saccharomyces boulardii against Candida albicans translocation from the gastrointestinal tract in immunosuppressed rats.

METHODS

Sixty rats were divided into five groups of 12. Group 1 was given only a laboratory pellet diet and water during the experiments; the other four groups were orally inoculated with C. albicans; and groups 3, 4, and 5 were also given prednisolone intraperitoneally. The treatment groups consisted of group 4, given S. boulardii orally, and group 5, given bombesin subcutaneously. The rats were killed after 10 days, and the large bowel, liver, spleen, and kidneys were removed for microbiological and histopathological examination. Blood samples were taken to measure tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1beta) levels, and the results were compared.

RESULTS

The number of translocated C. albicans colonies from the gastrointestinal tract and the serum TNF-alpha and IL-beta levels were significantly lower in groups 4 and 5 than in group 3 (P < 0.05). Histological analysis revealed that the bombesin-treated group (group 5) had significantly less mucosal ulceration and submucosal inflammation in the large bowel, less inflammation and necrosis in the liver, and less inflammation of the Bowman capsules in the kidney than the S. boulardii-treated group (group 4) (P < 0.05).

CONCLUSIONS

These findings show that both S. boulardii and bombesin inhibit the translocation of C. albicans from the gastrointestinal tract, although mucosal ulceration, submucosal inflammation in the large bowel, and dissemination in the liver and kidneys were significantly less severe in the bombesin-treated immunosuppressed rats.

Elevated serum beta-D-glucan level and depressed neutrophil phagocytosis in a heatstroke patient

Endotoxemia has been reported as a mechanism for the fatal sequela after heatstroke. Subsequent disseminated fungal infection in a heatstroke patient has been also described. Beta-D-glucan, a constituent of the fungal cell wall, is an early diagnostic measure for fungal infection. In a heatstroke case, we examined for the first time levels of serum beta-d-glucan and endotoxin. A 34-year-old man with a body temperature of 43.5 degrees C was admitted in a state of shock. Prior to the development of disseminated intravascular coagulopathy (DIC), a remarkable elevation of serum beta-D-glucan level to 116 pg/mL (normal level<6.0 pg/mL) was revealed on the first day of admission. However, serum endotoxin was not detected when using a method that excluded beta-D-glucan contamination from endotoxin measurement (normal level<1.0 pg/mL). This change of beta-D-glucan level was accompanied by a depressed neutrophil function, especially in phagocytosis of 34% (normal range 70-90%) but not in bacterocidal function (81% versus a normal range of 70-100%). After intensive care including continuous hemodiafiltration, the patient regained consciousness but remained ataxic due to cerebellar infarction, which might have resulted from DIC, and subsequent bilateral fungal oculitis were revealed 45 days after admission. This case report demonstrates the elevation of serum beta-D-glucan but normal endotoxin levels after heatstroke, which may prompt further study to re-examine the serum levels of endotoxin in such catastrophic insults.

Early diagnosis of invasive candidiasis with mannan antigenemia and antimannan antibodies

Late treatment of invasive candidiasis (IC) results in severe complications and high mortality. New tools are needed for early diagnosis. We conducted a retrospective study to assess the diagnostic utility of mannan antigenemia (Mn) and antimannan antibodies (anti-Mn) in neutropenic cancer patients at high risk for candidiasis. Twenty-eight patients with IC (based on European Organization for Research and Treatment of Cancer and Mycoses Study Group definitions) and 25 controls were studied. Mn and anti-Mn were positive (> or = 0.25 ng/mL and > or = 5 AU/mL, respectively) in 25/28 (89%) patients with candidiasis and in 4/25 (16%) controls: sensitivity, 89%; specificity, 84%; positive predictive value, 86%; negative predictive value, 88%. In patients with hepatosplenic lesions, assessing Mn/anti-Mn shortened the median time of diagnosis of candidiasis when compared with imaging (9 versus 25 days after fever onset as first sign of infection; P < 0.001). Candidiasis was diagnosed before neutrophil recovery in 78% and 11% of cases with Mn/anti-Mn and radiology, respectively (P < 0.001). Mn and anti-Mn may be useful for early noninvasive diagnosis of IC.

Clinical and microbiologic determinants of serious bloodstream infections in Egyptian pediatric cancer patients: a one-year study

OBJECTIVES

Bloodstream infections (BSI) remain a major cause of morbidity and death in patients undergoing treatment for cancer. However, all recent epidemiological and therapeutic studies underline the absolute need for knowledge of the factors governing the infections in each center. The aim of this study is to identify the factors affecting BSI in the pediatric service of the National Cancer Institute (NCI) at Cairo University. More tailored policies for the treatment of patients with febrile neutropenia following chemotherapy can then be created.

PATIENTS AND METHODS

Over a 12-month period, all children with cancer and fever, with or without neutropenia, who were admitted to the NCI for empirical therapy of febrile episodes and who had a microbiologically confirmed bloodstream infection were studied retrospectively.

RESULTS

A total of 328 BSI occurred in 1135 febrile episodes in pediatric cancer patients at the NCI in one year. Gram-positive bacteria were isolated in 168 episodes (51.2%) and 61.9% of the total isolates (either single or mixed), Gram-negative in 97 (29.6%), and mixed infections in 45 (13.7%). The common causative agents of bloodstream infections in this study were coagulase-negative staphylococci (16.2%), Staphylococcus aureus (13.4%), Streptococcus spp. (12.1%) followed by Acinetobacter spp. (6.7%) and Pseudomonas spp. (5.5%). Fungemia was encountered in 18 episodes, being mixed in nine of them. A more serious BSI in terms of a prolonged episode was encountered in 30.2% of the episodes and was significantly associated with patients being hospitalized, having intensified chemotherapy, polymicrobial and fungal infection, lower respiratory tract infections and persistent neutropenia at day seven.

CONCLUSIONS

In a large population of children, common clinical and laboratory risk factors were identified that can help predict more serious BSI. These results encourage the possibility of a more selective management strategy for these children.

Progressive disseminated histoplasmosis 10 years after return out of Africa in an immunocompetent host

We report on a patient without immunologic dysfunction who developed a reactivation of a latent histoplasma infection, acquired during a previous stay in Africa more than 10 years before. The current reactivation resulted in a subacute progressive disseminated histoplasmosis. He developed progressive weight loss, prostration and different oropharyngeal lesions together with bilateral adrenal masses on CT scan. The diagnosis was made on histology of biopsies of the oropharyngeal lesions. All systemic symptoms normalised, the oropharyngeal lesions disappeared and the adrenal masses regressed under amphotericin B therapy followed by itraconazole consolidation therapy.

Invasive fungal sinusitis: a 15-year review from a single institution

BACKGROUND

The aim of this study was to review our experience with patients with invasive fungal sinusitis (IFS) to determine outcomes and identify factors that may affect patient survival.

METHODS

A retrospective review was performed.

RESULTS

Forty-three patients were identified accounting for 45 cases of IFS. The underlying reasons for immunosuppression were hematologic malignancy (28 patients), diabetes mellitus (10 patients), solid organ transplant (3 patients), chronic steroid use (3 patients), and acquired immunodeficiency syndrome (1 patient). Eight of 45 cases (18%) died of IFS. Of the 28 cases associated with hematologic malignanancy, 3 patients died of IFS (11%) and 4 patients (14%) died of other causes with persistent IFS. None of these 7 patients had recovery of their absolute neutrophil count, and all patients who recovered from IFS recovered to a normal absolute neutrophil count. Four of 10 (40%) diabetic patients died of IFS, and 66% of survivors had persistent neurological or visual morbidity. The imortality rate was 29% for patients infected with Mucor and 11% for patients injected with Aspergillus.

CONCLUSION

We have found the overall mortality rate directly related to IFS to be 18%. The rate is higher for diabetic patients than for patients with hematologic causes for their immunosuppression. This is likely because of the higher index of suspicion and early diagnosis and treatment of patients with neutropenia and a less-fulminant, slower-progressing form of IFS from Aspergillus, apparently a less virulent fungus than Mucor. Intracranial involvement and failure to recover from neutropenia are the factors that led to poor prognosis in this series.

Infections by the yeast Kodomaea (Pichia) ohmeri: two cases and literature review

A 14-year-old boy who was neutropenic following chemotherapy for leukemia developed fungemia caused by the yeast Kodomaea ohmeri ( Pichia ohmeri). The infection was cured by catheter removal and the use of fluconazole. A 74-year-old man who had undergone surgeries for a subcutaneous tumor developed polymicrobic cellulitis involving Kodomaea ohmeri. Despite surgical debridement and antibiotic therapy, the patient died of complications. Including these 2 cases, there have been 10 Kodomaea ohmeri infections reported thus far, all occurring in patients with pre-existing conditions. There have been seven cases of fungemia and one case each of peritonitis, funguria, and cellulitis. The treatment employed varied depending on the site/source of infection. Seven patients recovered and three died. The microbiological data available suggest that Kodomaea ohmeri can be identified definitively by biochemical tests and is susceptible to amphotericin B and either susceptible to or dose dependently susceptible to itraconazole and fluconazole.

Case report: Invasive aspergillosis successfully treated with voriconazole without recurrence during subsequent bone marrow transplantation

Invasive aspergillosis is an important cause of morbidity and mortality among immunosuppressed oncology patients. We report a 17-year-old patient with a T cell acute lymphocytic leukemia and invasive aspergillosis treated with voriconazole who remained infection-free during bone marrow transplant.

Pulmonary Aspergillosis in a Patient with Chronic Granulomatous Disease: Confirmation by Polymerase Chain Reaction and Serological Tests, and Successful Treatment with Voriconazole

A 25-year-old male with chronic granulomatous disease developed severe bilateral pulmonary aspergillosis confirmed by a positive result of polymerase chain reaction for Aspergillus species from sputum and positive serological tests for Aspergillus. He was successfully treated with voriconazole. The diagnostic difficulties and the new therapeutic options in the era of new antifungal agents are discussed.

Diagnosis of fungal infection: new technologies for the mycology laboratory

The dramatic increase in nosocomial invasive mycoses over the past two decades has led to increased interest in the area of antifungal development. Unfortunately, the infusion of new diagnostic technology into the clinical mycology laboratory has lagged behind. Although newer, automated, continuous-monitoring blood culture systems are as sensitive as the older, manual "gold standard" system, the recovery of fungi from blood, as well as other clinical specimens, remains an insensitive marker for invasive fungal infection. Antigen assays for the rapid diagnosis of invasive fungal infections are in development, and galactomannan and glucan are two such promising antigens. Glucan may be present in the blood of patients with infection secondary to a wide variety of fungal pathogens, including Candida, Aspergillus, Fusarium, Saccharomyces, Trichosporon and Acremonium species. Early data suggest galactomannan may be present in the blood in detectable levels very early in the course of invasive aspergillosis. The galactomannan assay currently undergoing evaluations may actually be positive prior to the clinical suspicion for infection and may be useful in monitoring therapeutic response as well; however, the etiology of false-positive results following cytotoxic chemotherapy still has to be elucidated. PCR assays are also being developed in the research laboratory, however, the PCR assays will require a significant amount of adaptation and validation before they are ready for clinical care. Well-planned studies to evaluate the performance characteristics as well as appropriate clinical and cost-effective application of these new tests are needed.

Immunity to Candida

Candida species are commensal fungal organisms as well as opportunistic pathogens of mucosal tissues. From the commensal relationship, most healthy individuals have demonstrable Candida-specific immunity. In immunocompromised persons, however, fungal infections caused primarily by C. albicans often occur. In HIV disease, up to 90% of HIV+ persons will have a symptomatic episode of oropharyngeal candidiasis (OPC) sometime during progression to AIDS, many of which become recurrent. In contrast, vulvovaginal candidiasis (VVC) and systemic Candida infections (candidaemia) are much less common during HIV disease, indicating the diversity and compartmentalization of the host response to Candida. Both innate resistance and acquired immunity play some role in maintaining C. albicans in the commensal state and protecting the systemic circulation. Polymorphonuclear leukocytes (PMNL) are critical for protection against systemic infections, whereas cell-mediated immunity (CMI) by Th1-type CD4+ T-cells is important for protection against mucosal infections. However, there is a discordant role for CMI at the vaginal versus oral mucosa, whereas little to no role for local or systemic CMI is evident at the vaginal mucosa. In contrast, there is a strong correlation between reduced blood CD4+ cells and the incidence of OPC, but it remains unclear whether systemic or local CMI is more important. Evaluation of systemic CMI in a cohort of HIV+ individuals with and without mucosal candidiasis revealed that Candida-specific CMI is not different between HIV+ persons with OPC or VVC and HIV- persons. Thus, the correlation of reduced CD4+ cell numbers to OPC may be explained by the requirement for a threshold number of systemic CD4+ cells to protect the oral mucosa together with the status of local immunity. Indeed, HIV+ persons with and without OPC had a Th2-type salivary cytokine profile suggestive of susceptibility to Candida infection compared with a protective Th0/Th1-type profile in HIV- persons. Candida-specific antibodies, although present, are controversial relative to a role in protection or eradication of infection. While studies of mucosal innate resistance are limited, we recently found that epithelial cells from saliva and vaginal lavages of healthy individuals inhibit the growth of Candida in vitro. This epithelial cell anti-Candida activity requires cell contact by viable cells with no role for soluble factors, including saliva. Interestingly, oral epithelial cells from HIV+ persons with OPC had significantly reduced activity, indicating some protective role for the epithelial cells. Taken together, these data suggest that immunity to Candida is site-specific, compartmentalized and involves innate and/or acquired mechanisms from systemic and/or local sources.

Pulmonary mucormycosis in a diabetic renal transplant patient

A 50-year-old male, diabetic, post transplant patient had recurrent pneumonia. The first episode responded well to antibiotics, while on the second occasion he had a necrotising pneumonia, which developed into a thick-walled cavity. Despite antibiotics, his condition rapidly deteriorated precluding bronchoscopy or percutaneous biopsy. Post-mortem lung biopsy revealed typical hyphae of mucormycosis.

Immunology of diseases associated with Malassezia species

Malassezia species are members of the human cutaneous commensal flora, in addition to causing a wide range of cutaneous and systemic diseases in suitably predisposed individuals. Studies examining cellular and humoral immune responses specific to Malassezia species in patients with Malassezia-associated diseases and healthy controls have generally been unable to define significant differences in their immune response. The use of varied antigenic preparations and strains from different Malassezia classifications may partly be responsible for this, although these problems can now be overcome by using techniques based on recent work defining some important antigens and also a new taxonomy for the genus. The finding that the genus Malassezia is immunomodulatory is important in understanding its ability to cause disease. Stimulation of the reticuloendothelial system and activation of the complement cascade contrasts with its ability to suppress cytokine release and downregulate phagocytic uptake and killing. The lipid-rich layer around the yeast appears to be pivotal in this alteration of phenotype. Defining the nonspecific immune response to Malassezia species and the way in which the organisms modulate it may well be the key to understanding how Malassezia species can exist as both commensals and pathogens.

Galactomannan enzyme immunoassay for monitoring systemic infection with Aspergillus fumigatus in mice

Intravenous (i.v.) infection of immunocompetent mice with Aspergillus fumigatus was used to investigate the ability of a commercial galactomannan enzyme-linked immunosorbent assay (ELISA) to monitor the course of organ infection after dissemination. The test detected 100% of the fungemias which occurred for up to 5 days after infection. When blood-cultures became negative but there was a high load of fungi in the parenchymal organs and a positive culture from the brain, the ELISA was again positive in all animals. However, when blood cultures as well as brain cultures were negative and lower amounts of fungi demarcated by immune cells were present in the liver and kidneys which was the case between day 5 and 30 of infection, the test was negative in most of the animals. Therefore, the test was excellent for detection of early i.v. infection with Aspergillus fumigatus but not suited for detection of limited organ infection in immunocompetent mice.

Transient fungemia due to Rhodotorula rubra in a cancer patient: case report and review of the literature

A unique case of Rhodotorula rubra transient fungemia in a post-chemotherapy, febrile neutropenic patient with colon cancer, suffering from gastrointestinal mucositis, is described. The fungus was isolated repeatedly from his blood. However, all signs and symptoms of the infection disappeared, without antifungal treatment, as soon as neutropenia and mucositis, both of short duration, resolved. Restoration of the patient's defense mechanisms was adequate for disappearance of the fungus from the patient's blood and full recovery.

Blood lysate staining, a new microscopic method for diagnosis of fungemia using peripheral blood

We developed a microscopy method for the detection of fungal cells in peripheral blood, termed blood lysate staining, using an approximately 5x5 mm dotted blood lysate. This method was able to detect the emerging fungal pathogen Trichosporon asahii in murine models of systemic fungal infection and fungemia in patients quickly and at minimal cost. Pathogenic yeasts were successfully detected in 6 of 8 blood samples which were taken from feverish immunocompromised patients who were clinically suspected of having fungal infections. Fungal cells were observed as ovoid to elongated, 3x3 to 7x10 microm, and occurred singly, budding, and in short chains and clusters in a periodic acid-Schiff-stained blood smear. The yeast cells were easily distinguished from blood-cell debris by their size, shape and smooth yet rigid outline.

[Clinical case of the month. Disseminated fusariosis in a immunocompromised patient]

Fusarium spp are ubiquitous soil saprophytes and occasional plant pathogens. Fusariosis in humans is usually limited to superficial mycoses. We report the case of a disseminated fungal infection due to Fusarium spp in an immunosuppressed patient suffering from acute lymphoblastic leukemia. This report and review of the recent literature suggest that Fusarium spp are emerging fungal pathogens in immunosuppressed patients.

Antifungal agents and immunomodulators in systemic mycoses

The rising incidence of fungal infections and the emergence of several fungi as opportunistic pathogens have reawakened interest in chemotherapeutic and prophylactic agents for mycoses. During the past decades significant advances have been made in the development of novel antifungal agents for treatment of systemic mycoses. This brief review presents an update of the available information on polyenes, imidazoles, triazoles, flucytosine, allylamines, echinocandins, nikkomycins, sordarins and immunomodulators. A reference has also been made to the work in antifungals done or in progress at the Central Drug Research Institute (CDRI), Lucknow. Currently, antifungals represent more than 6% of the total world market for anti-infective agents and with 20% annual expansion they are expected to cross the 15 billion US Dollars in value within a decade.

Do kinetics of the humoral response to Cryptococcus neoformans proteins during murine cryptococcosis reflect outcome?

The kinetics of the humoral response to Cryptococcus neoformans proteins were studied in outbred mice infected with isolate NIH52D. Future nonsurvivors had earlier and stronger (i.e., more bands recognized) humoral responses than survivors. In addition, antibodies to a 56- to 60-kDa membrane antigen and to a 39- to 40-kDa cytosolic antigen were detected more frequently in samples from future nonsurvivors and from survivors, respectively (P < 0.05).

Immunization with the Candida albicans membrane fraction and in combination with fluconazole protects against systemic fungal infections

We studied the immunogenicity of a membrane fraction prepared from Candida albicans cells called C. albicans membrane antigen (CMA). The present study revealed that CMA immunization has antifungal activity in mouse models of systemic fungal infection. Immunization of mice by subcutaneous injections of CMA with incomplete Freund adjuvant induced resistance to infections caused not only by C. albicans but also by Aspergillus fumigatus. The level of resistance to candidiasis was as high as that induced by whole-cell immunization. The acquired resistance to candidiasis in the mice immunized with CMA was not diminished by immunosuppressive treatment with cyclophosphamide. The level of resistance to fungal infections was superior to that given by fluconazole (FLC) treatment alone and highly enhanced by the combination with FLC. When CD4(+) cells in CMA-immunized mice were depleted by a monoclonal antibody, the antifungal activity induced by the combination of CMA and FLC was significantly reduced. These results indicate that immunization with CMA is useful for preventing systemic fungal infections and in combination with FLC for increasing resistance after infection.

Increased severity of Candida vaginitis in BALB/c nu/nu mice versus the parent strain is not abrogated by adoptive transfer of T cell enriched lymphocytes

The role of the host immune system in combating candidal infections in the vagina is poorly understood. A murine model of Candida vaginitis was used to elucidate the role of T cells in a candidal infection. Athymic BALB/c nu/nu mice or normal BALB/c mice were induced into estrus and then infected with 1 x 10(6) Candida albicans intravaginally. The infection was monitored over 1 week. Samples from blood, small intestine, tongue, kidney, spleen, liver, uterus and vagina were tested for recoverable C. albicans. Histology of the vagina was assessed for both inflammation and extent of infection. Results indicated that the BALB/c nu/nu mice had similar levels of vaginal yeast load to the normal BALB/c mice. In 25-30% of nude mice Candida was also recovered from extra vaginal sites (kidney, liver, small intestine), however, extra vaginal dissemination was not observed in any normal BALB/c animals. Histologically, both the nu/nu and control BALB/c had similar levels of vaginal inflammation; however, the nu/nu mice had more florid fungal growth in the vaginal epithelium. Adoptive transfer of either immune or non-immune BALB/c T cells into nude mice had no affect on either infection or vaginal inflammation. Immunohistochemical staining of vaginal tissues from normal BALB/c mice or nude mice adoptively transferred with either immune or non-immune T cells with anti-CD3 monoclonal antibody revealed no significant difference between groups in the numbers of CD3+ vaginal T cells. However, in mice receiving either immune or non-immune T cells no yeast was recovered from any tissues except the vagina. These data show that T cells have a limited role in protecting the vagina from C. albicans infection.

New perspectives in the diagnosis of systemic fungal infections

Profound and prolonged neutropenia following chemotherapy is a major risk factor for systemic fungal infections. Mortality associated with disseminated fungal infection is high, and treatment with conventional amphotericin B is complicated by renal toxicity. Candida and Aspergillus are among the major pathogens in these patients. Many patients remaining neutropenic over a prolonged period of time will receive empirical antifungal therapy. The clinical and laboratory diagnoses of these infections are neither sensitive nor specific and are generally limited in the early detection of invasive fungal infection. However, several new approaches to diagnosis are being developed, which should be translated into routine practice, based on a greater understanding of the pathogenesis of systemic fungal infection and virulence determinants of fungal pathogens. These include antigen detection and polymerase chain reaction. Patients with presumed fungal infection require more intense and accurate monitoring for signs of disseminated infection. Early diagnosis may guide appropriate treatment and prevent mortality. Continued development of commercial tests should help achieve the objective of definitive diagnostic tests for systemic fungal infections.

Immune response in patients with persistent candiduria and occult candidemia

PURPOSE

We evaluated the immunological response in patients with persistent candiduria with or without occult candidemia.

MATERIALS AND METHODS

Levels of Thl (pro-inflammatory interleukin [IL]-1, IL-2 and tumor necrosis factor-alpha) and Th2 (anti-inflammatory IL-4 and IL-10) cytokines were measured in the sera of patients with persistent candiduria. Polymerase chain reaction assessment of the 158 base pair candidal actin gene was used to detect Candida albicans in blood to identify occult candidemia.

RESULTS

During a 14-month period 66 hospitalized patients with a mean age of 63 years (range 44 to 80) with persistent candiduria were evaluated. Occult candidemia developed in 27 patients (41%) as evidenced by detection of candidal actin gene in the sera by polymerase chain reaction. Risk factors included antibiotics in 27 patients (100%), central venous catheter in 22 (81%), urinary catheter in 21 (78%), total parenteral nutrition in 18 (66%), diabetes mellitus in 16 (59%) and abdominal surgery in 14 (52%). A total of 17 age matched patients with a mean age of 59 years hospitalized for elective general or vascular surgical procedures with no clinical or laboratory evidence of urinary or hematogenous fungal or bacterial infection served as controls. Serum levels of Th2 cytokines were elevated in 18 of 39 patients with persistent candiduria alone, and in 22 of 27 patients with candiduria and occult candidemia compared to controls (p<0.002). Th1 cytokines were within normal limits or slightly decreased in all patients with persistent candiduria with or without candidemia.

CONCLUSIONS

These observations indicate that an abnormal immune response develops in patients with persistent candiduria with or without candidemia.

The use of an in-house modified double antibody sandwich ELISA to detect Aspergillus antigens in sera of immunosuppressed patients

AIM

The purpose of this study was to retrospectively detect Aspergillus antigens in sera obtained from immunocompromised host using an in-house modified double antibody sandwich ELISA.

MATERIALS AND METHODS

The ELISA employed the use of polyclonal antibodies raised against a water-soluble (WS) mycelial component of a clinical isolate of Aspergillus fumigatus. Rabbit and guinea-pig anti-WS antibodies were used as the capture and detector antibodies respectively. This was followed by the addition of anti-guinea pig antibodies conjugated to horse radish peroxidase and orthophenylenediamine.

RESULTS

Of 143 specimens obtained from 140 patients, only 5 (3.5%) specimens demonstrated the presence of antigen. The 5 antigen-positive sera were from three patients. One was a confirmed case of paranasal aspergillosis and the other two were probable cases of invasive aspergillosis.

CONCLUSION

The clinical validity of the ELISA should be determined by prospective detection of Aspergillus antigens in multiple serum samples collected from proven cases of invasive aspergillosis.

Immune determinants of organism and outcome in febrile hospitalized Thai patients with bloodstream infections

Opportunistic infections (OI) and the human immunodeficiency virus (HIV) cause significant morbidity and mortality in developing countries. Immune cell and cytokine profiles may be related to the type and course of OI and to the OI-HIV interaction. Examining cell-specific cytokine production ex vivo has only recently become feasible. In Thailand, 53 febrile, hospitalized adults were enrolled in a study of the immune correlates of bloodstream infections (BSI). On site, blood cells were stimulated ex vivo. Cell-surface antigens and eight intracellular cytokines were subsequently analyzed using flow cytometry to determine associations with mortality and the organism causing the BSI. By logistic regression analysis, the percentage of CD3(+) CD16/56(+) cells making tumor necrosis factor alpha (TNF-alpha) (P = 0.033) and the percentage of CD3(-) CD16/56(+) cells (NK) (P = 0.032) were related to HIV positivity. Lymph node enlargement with HIV infection and the percentage of CD3(+) CD16/56(+) making TNF-alpha were predictive of death. A lower percentage of CD3(+) CD8(+) lymphocytes making interleukin-8 (IL-8) (P = 0.005), fewer monocytes expressing CD14 (P = 0.009), and the percentage of CD3(+) CD8(+) cells producing gamma interferon (P = 0. 011) were associated with blood culture positivity and the causative organism. For every one point decrease in the percentage of CD3(+) CD8(+) cells making IL-8, the likelihood of a positive culture increased 23%; for every one point decrease in the percentage of monocytes expressing CD14, the likelihood of a positive culture increased by 5%. Only a few immune cell types and three of their related cytokines were significantly associated with HIV disease outcome or the BSI organism. These cell types did not include CD3(+) CD8(-) cells (a surrogate for CD4(+) cells), nor did they involve cytokines associated with a type I to type II cytokine shift, which might occur with advancing HIV infection. These associations support the premise that CD8(+) and CD16/56(+) lymphocytes play significant roles in HIV and type I infections.

Candida dubliniensis candidemia in patients with chemotherapy-induced neutropenia and bone marrow transplantation

The recently described species Candida dubliniensis has been recovered primarily from superficial oral candidiasis in HIV-infected patients. No clinically documented invasive infections were reported until now in this patient group or in other immunocompromised patients. We report three cases of candidemia due to this newly emerging Candida species in HIV-negative patients with chemotherapy-induced immunosuppression and bone marrow transplantation.

Update on detection of bacteremia and fungemia

The presence of microorganisms in a patient's blood is a critical determinant of the severity of the patient's illness. Equally important, the laboratory isolation and identification of a microorganism present in blood determine the etiologic agent of infection, especially when the site of infection is localized and difficult to access. This review addresses the pathophysiology and clinical characteristics of bacteremia, fungemia, and sepsis; diagnostic strategies and critical factors in the detection of positive blood cultures; characteristics of manual and instrument approaches to bacteremia detection; approaches for isolating specific microorganisms associated with positive blood cultures; and rapid methods for the identification of microorganisms in blood cultures.

Candidemia in acute leukemia patients

Fungal infections are an important cause of morbidity and mortality in patients with acute leukemia (AL). Candidemia, once rare, is now a common nosocomial infection because of the intensity of chemotherapy, prolonged neutropenia, administration of broad-spectrum antibiotics and use of central venous catheters (CVC). We retrospectively identified patients treated for AL from 6/86 to 6/95 who also had candidemia. We describe 28 patients (incidence 6.3%) with a median age of 39 years, 24 of whom were on remission induction and 4 on postremission chemotherapy. All patients had CVC and empiric antimicrobial therapy, 4 had been given prophylactic antifungal drugs, and 2 had parenteral nutrition. Neutropenia was profound (median leukocyte nadir 200/microliters, median duration 19 days). Candida was isolated in blood cultures 10 days (median) after the start of neutropenia. The clinical presentation included fever (100%), respiratory symptoms (71.4%), skin lesions (39.2%) and septic shock (17.8%). Amphotericin B was given to 17 patients and liposomal amphotericin to 5 patients. Infection resolved in 18 patients (64.2%). 10 of whom were in complete remission. Mortality from candidemia was 17.8% (5/28). In conclusion, fungal infections are responsible for death in a significant number of patients. In our series treatment success was related to its rapid onset and to the recovery of neutropenia.

Multicenter randomized trial of fluconazole versus amphotericin B for treatment of candidemia in non-neutropenic patients. Canadian Candidemia Study Group

A randomized trial was conducted to compare the efficacy and safety of fluconazole versus that of amphotericin B in the treatment of candidemia in non-neutropenic adults. Enrollment was stratified by disease severity (APACHE II score). Patients were randomized (1:1) to receive amphotericin B 0.6 mg/kg/day (cumulative dose 8 mg/kg) or fluconazole 800 mg intravenous loading dose, then 400 mg daily for four weeks (intravenous for at least 10 days). Patients were monitored for six months. A total of 106 patients were enrolled. A protocol amendment implemented midway through the trial required patients to be removed from the study and treated with amphotericin B if species identification indicated candidemia due to Candida glabrata or Candida krusei. Baseline characteristics were similar for the two groups; 103 patients (fluconazole, 50; amphotericin B, 53) met the major enrollment criteria. The intention-to-treat analysis indicated successful therapy in 50% of fluconazole recipients compared to 58% of the amphotericin B group (p = 0.39; one-sided 95% CI, -8 to 24%). The efficacy analysis included 84 patients (fluconazole, 42; amphotericin B, 42); successful outcomes were observed in 57% and 62% of cases in the fluconazole and amphotericin B groups, respectively (p = 0.66: one-sided 95% CI, -12 to 22%). The mortality at day 14 for the fluconazole group was 26% and for the amphotericin B group 21% (p = 0.52; chi-square test) and remained similar throughout the course of follow-up, Drug-related adverse events were more frequent with amphotericin B than with fluconazole and prompted switching of therapy for two (4%) and zero cases, respectively. Fluconazole and amphotericin B were associated with similar clinical response rates and survival in the treatment of candidemia among non-neutropenic patients; however, drug-related adverse events were more frequent with amphotericin B.