Nosocomial fungal infections: candidemia

The Role of Adjuvant Systemic and Intravitreal Corticosteroids in Fungal Endophthalmitis Treatment

Endophthalmitis refers to inflammation involving internal ocular structures, including the anterior and posterior eye segments, associated with infectious agents, most commonly bacteria and fungi. This review focuses on endophthalmitis caused by fungi. Medical and surgical management are the two main treatment modalities for fungal endophthalmitis, with medical management utilizing systemic or intravitreal antifungals. The use of systemic or intravitreal corticosteroids as an adjuvant treatment to dampen the severity of inflammation is controversial. Based on the pathobiology of fungal endophthalmitis as well as the mechanism of action of corticosteroids, it was hypothesized that corticosteroids affected the immune response against fungal infection. In vitro studies mostly carried out during the 1980s showed that dexamethasone plays a role in the suppression of phagocytosis of yeasts and demonstrated the facilitation of yeast proliferation by dexamethasone. In vivo studies analysis was compromised entirely of retrospective studies describing steroid use in fungal endophthalmitis, with the outcomes of the patients in these studies varying greatly and often being anecdotally noted, thus difficult to discern any definitive results. Given the limited clinical data and the heterogeneity of the existing studies, additional experimentation human studies with clinical trials or observations over more extended periods analyzing the effect of systemic and intravitreal corticosteroids in fungal endophthalmitis are needed before definitive conclusions can be drawn.

Advances in prophylaxis and treatment of invasive fungal infections: perspectives on hematologic diseases

Invasive fungal infections (IFIs) are common causes of mortality and morbidity in patients with hematologic diseases. Delayed initiation of antifungal treatment is related to mortality. Aspergillus sp. is the leading cause of IFI followed by Candida sp. Diagnosis is often challenging owing to variable conditions related to underlying diseases. Clinical suspect and prompt management is important. Imaging, biopsy, and non-culture-based tests must be considered together. New diagnostic procedures have been improved, including antigen-based assays and molecular detection of fungal DNA. Among hematologic diseases, patients with acute myeloid leukemia, myelodysplastic syndrome, recipients of hematopoietic stem cell transplantation are at high risk for IFIs. Antifungal prophylaxis is recommended for these high-risk patients. There are continuous attempts to achieve ideal management of IFIs. Scoring system for quality control has been developed with important recommendations of current guidelines. Higher adherence to guidelines is related to decreased mortality in IFIs.

Biologic mesh infection with Candida albicans after abdominal wall reconstruction with calcium sulphate antibiotic beads: A case report

Mesh infection after abdominal wall reconstruction is a rare and usually devastating complication. Herein, we describe a unique case of a delayed and non-lethal Candida albicans mesh infection after abdominal wall reconstruction with placement of a biologic graft impregnated with antibiotics. Mesh explantation was not required, and the wound healed by secondary intention. This work suggests that locally delivered antibiotics may change the culprit microbes of skin infections to more unusual species such as Candida spp. Future research is required to study the effect of including antifungal agents in the locally delivered antimicrobials for abdominal wall reconstructions with biological meshes.

Fungal Endophthalmitis: A Comprehensive Review

Endophthalmitis is a serious ophthalmologic condition involving purulent inflammation of the intraocular spaces. The underlying etiology of infectious endophthalmitis is typically bacterial or fungal. The mechanism of entry into the eye is either exogenous, involving seeding of an infectious source from outside the eye (e.g., trauma or surgical complications), or endogenous, involving transit of an infectious source to the eye via the bloodstream. The most common organism for fungal endophthalmitis is Candida albicans. The most common clinical manifestation of fungal endophthalmitis is vision loss, but other signs of inflammation and infection are frequently present. Fungal endophthalmitis is a clinical diagnosis, which can be supported by vitreous, aqueous, or blood cultures. Treatment involves systemic and intravitreal antifungal medications as well as possible pars plana vitrectomy. In this review, we examine these essential elements of understanding fungal endophthalmitis as a clinically relevant entity, which threatens patients’ vision.

Danish Whole-Genome-Sequenced Candida albicans and Candida glabrata Samples Fit into Globally Prevalent Clades

Candida albicans and Candida glabrata are opportunistic fungal pathogens with increasing incidence worldwide and higher-than-expected prevalence in Denmark. We whole-genome sequenced yeast isolates collected from Danish Clinical Microbiology Laboratories to obtain an overview of the Candida population in the country. The majority of the 30 C. albicans isolates were found to belong to three globally prevalent clades, and, with one exception, the remaining isolates were also predicted to cluster with samples from other geographical locations. Similarly, most of the eight C. glabrata isolates were predicted to be prevalent subtypes. Antifungal susceptibility testing proved all C. albicans isolates to be susceptible to both azoles and echinocandins. Two C. glabrata isolates presented azole-resistant phenotypes, yet all were susceptible to echinocandins. There is no indication of causality between population structure and resistance phenotypes for either species.

Predictive Virtual Infection Modeling of Fungal Immune Evasion in Human Whole Blood

Bloodstream infections by the human-pathogenic fungi Candida albicans and Candida glabrata increasingly occur in hospitalized patients and are associated with high mortality rates. The early immune response against these fungi in human blood comprises a concerted action of humoral and cellular components of the innate immune system. Upon entering the blood, the majority of fungal cells will be eliminated by innate immune cells, i.e., neutrophils and monocytes. However, recent studies identified a population of fungal cells that can evade the immune response and thereby may disseminate and cause organ dissemination, which is frequently observed during candidemia. In this study, we investigate the so far unresolved mechanism of fungal immune evasion in human whole blood by testing hypotheses with the help of mathematical modeling. We use a previously established state-based virtual infection model for whole-blood infection with C. albicans to quantify the immune response and identified the fungal immune-evasion mechanism. While this process was assumed to be spontaneous in the previous model, we now hypothesize that the immune-evasion process is mediated by host factors and incorporate such a mechanism in the model. In particular, we propose, based on previous studies that the fungal immune-evasion mechanism could possibly arise through modification of the fungal surface by as of yet unknown proteins that are assumed to be secreted by activated neutrophils. To validate or reject any of the immune-evasion mechanisms, we compared the simulation of both immune-evasion models for different infection scenarios, i.e., infection of whole blood with either C. albicans or C. glabrata under non-neutropenic and neutropenic conditions. We found that under non-neutropenic conditions, both immune-evasion models fit the experimental data from whole-blood infection with C. albicans and C. glabrata. However, differences between the immune-evasion models could be observed for the infection outcome under neutropenic conditions with respect to the distribution of fungal cells across the immune cells. Based on these predictions, we suggested specific experimental studies that might allow for the validation or rejection of the proposed immune-evasion mechanism.

Evaluating of fungal contamination in hospital wet cooling systems in Markazi province, Central Iran

OBJECTIVE

Fungal infections are common complication among hospitalized patients especially between who is immunocompromised. Wet cooling systems in the hospital environment play a critical role as a source of these infections. The aim of this study was survey of wet cooling system of hospitals for fungal contamination in Arak city.

MATERIALS AND METHODS

This study was conducted during May to September of 2016. Sampling was done as random. Samples were obtained from water and straw of 84 wet cooling systems of four hospitals in Arak city. Samples were cultured in Sabouraud dextrose agar medium contain of chloramphenicol. Identification of fungi was performed by Slide culture method.

RESULTS

From 84 wet cooling systems, 32 (38.1%) were contaminated with fungi. The highest fungal contamination was found in wards of oncology and CCU. The most prevalent of fungi isolated in this study were Aspergillus spp. and Candida spp., respectively.

CONCLUSION

The findings of this descriptive cross-sectional study clearly indicate, in wards of the hospital that used wet cooling systems, there was considerable fungal contamination, particularly Aspergillus contamination. These results highlight a clear need for greater attention to the use of non-aqueous or closed circulation cooling systems, especially where susceptible patients receive medical care.

Multicenter Evaluation of Risk Factors for Aspergillosis in Patients Treated with Lipid Amphotericin B Products: Outcomes, Drug Utilization Parameters, and Benchmarking

Purpose

To evaluate the use of lipid amphotericin B products in relation to risk factors for aspergillosis and candidemia at the time therapy was initiated.

Methods

A single-group, concurrent, observational, multicenter study in hospitalized patients receiving a lipid amphotericin B product (Abelcet or AmBisome) was undertaken. The severity of illness, duration of therapy, length of hospital stay, microbiology, all-cause mortality, physician specialty, and clinical characteristics of each patient was recorded. Risk factors for aspergillosis and candidemia and process markers that might identify patients as candidates for lipid amphotericin B therapy were collected.

Results

One hundred eighty-six patients were enrolled in six US medical centers. One hundred four patients had positive fungal cultures; the majority of positive cultures were for Candida albicans (n = 40) or yeast (n = 27). Sixteen patients had positive cultures for Aspergillus. All patients receiving a lipid amphotericin B product had an overall statistically significantly greater number of risk factors for Candida vs Aspergillus infection. The mean (± SD) number of risk factors for Aspergillus was 2.46 ± 1.97 (range 0–10) and for Candida was 7.77 ± 3.14 (range 1–16) (P < 0.05). Risk factor assessment by medical service showed a statistically significantly larger number of Aspergillus risk factors in the bone marrow transplant (BMT) service compared with all other services (P < 0.05).

Conclusions

There were fewer documented risk factors for aspergillosis than candidemia in patients receiving a lipid amphotericin B product. Establishing drug usage protocols that include culture analysis, risk factor identification, high-risk medical services, and incorporation of drug use evaluation measures can guide the practitioner in selecting the appropriate therapy for their patients.

Antifungal activity of ionic liquids based on (-)-menthol: a mechanism study

The mechanism of toxicity of chiral ionic liquids with (1R,2S,5R)-(-)-menthol [C_n-Am-Men][Cl] (n=10, 11 or 12) in the fungus Candida albicans is reported here. Ionic liquids were more toxic towards Candida strain lacking all identified multidrug resistance efflux pumps. Moreover, the compounds tested inhibited C. albicans filamentation at the concentration at which detached fungal cells also adhered to the plastic surface. Our results showed the high activity of all the tested chiral ionic liquids in the permeabilization of C. albicans' membranes and in the digestion and interruption of the cell wall. The investigated ionic liquids thus have potential as disinfectants because besides their antifungal and antiadhesive action these compounds do not cause hemolysis.

Pharmacological evaluation of poly(3-methylthiophene) and its titanium(IV)phosphate nanocomposite: DNA interaction, molecular docking, and cytotoxic activity

Cancer and pathogenic microbial diseases have terribly affected human health over a longer period of time. In response to the increasing casualties due to cancer and microbial diseases, unique poly(3-methylthiophene) and poly(3-methylthiophene)-titanium(IV)phosphate composite were prepared via in-situ oxidative chemical polymerization in this work. The poly(3-methylthiophene) and poly(3-methylthiophene)-titanium(IV)phosphate composite were well characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. DNA binding studies by UV-Visible and fluorescence spectroscopic investigations indicated strong binding affinities of poly(3-methylthiophene) and poly(3-methylthiophene)-titanium(IV)phosphate nanocomposite; leading to structural damage of DNA. Poly(3-methylthiophene)-titanium(IV)phosphate nanocomposite showed stronger interactions with DNA as compared to poly(3-methylthiophene) and from dye displacement assay it was confirmed that mode of binding of both the formulations was intercalative. The antimicrobial screening revealed that polymer and its composite displayed stronger antibacterial effects than ampicillin against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhimurium. Besides, the poly(3-methylthiophene) and poly(3-methylthiophene)-titanium(IV)phosphate nanocomposite showed dose dependent effects towards estrogen receptor positive breast cancer (MCF-7) and estrogen receptor negative breast cancer (MDA-MB-231) cell lines; with poly(3-methylthiophene)-titanium(IV)phosphate nanocomposite showing better activities against both cell lines. In all in-vitro biological investigations, poly(3-methylthiophene)-titanium(IV)phosphate composite showed superior properties to that of the pure poly(3-methylthiophene), which encouraged us to suggest its potential as future therapeutic gear in drug delivery and other allied fields.

Secular Trends of Candidemia in a Large Tertiary-Care Hospital From 1988 to 2000: Emergence ofCandida parapsilosis

Objective:

To analyze the secular trends of candidemia in a large tertiary-care hospital to determine the overall incidence, as well as the incidence by ward and by species, and to detect the occurrence of outbreaks.

Design:

Retrospective descriptive analysis. Secular trends were calculated using the Mantel-Haenszel test.

Setting:

A large tertiary-care referral center in Spain with a pediatric intensive care unit (ICU) to which more than 500 children with congenital cardiac disease are admitted annually.

Patients:

All patients with candidemia occurring from 1988 to 2000 were included. Cases were identified from laboratory records of blood cultures.

Results:

There were 331 episodes of candidemia. The overall incidence of nosocomial candidemia was 0.6 episode per 1,000 admissions and remained stable throughout the study period (P= .925). The species most frequently isolated wasCandida albicans, but the incidence ofC. parapsilosiscandidemia increased (P= .035). In the pediatric ICU, the incidence ofC. parapsilosiswas 5.6 episodes per 1,000 admissions and it was the predominant species. Outbreaks occurred occasionally in the pediatric ICU, suggesting nosocomial transmission.

Conclusions:

During this 13-year period, the incidence of candidemia remained stable in this hospital, butC. parapsilosisincreased in frequency. Occasional outbreaks of candidemia suggested nosocomial transmission ofCandidaspecies (Infect Control Hosp Epidemiol2005;26:548-552).

Antifungal Activity of Bee Venom and Sweet Bee Venom against Clinically Isolated Candida albicans

OBJECTIVES

The purpose of this study was to investigate the antifungal effect of bee venom (BV) and sweet bee venom (SBV) against Candida albicans (C. albicans) clinical isolates.

METHODS

In this study, BV and SBV were examined for antifungal activities against the Korean Collection for Type Cultures (KCTC) strain and 10 clinical isolates of C. albicans. The disk diffusion method was used to measure the antifungal activity and minimum inhibitory concentration (MIC) assays were performed by using a broth microdilution method. Also, a killing curve assay was conducted to investigate the kinetics of the anti- fungal action.

RESULTS

BV and SBV showed antifungal activity against 10 clinical isolates of C. albicans that were cultured from blood and the vagina by using disk diffusion method. The MIC values obtained for clinical isolates by using the broth microdilution method varied from 62.5 μg/ mL to 125 μg/mL for BV and from 15.63 μg/mL to 62.5 μg/mL for SBV. In the killing-curve assay, SBV behaved as amphotericin B, which was used as positive control, did. The antifungal efficacy of SBV was much higher than that of BV.

CONCLUSION

BV and SBV showed antifungal activity against C. albicans clinical strains that were isolated from blood and the vagina. Especially, SBV might be a candidate for a new antifungal agent against C. albicans clinical isolates.

Identification of Scedosporium boydii catalase A1 gene, a reactive oxygen species detoxification factor highly expressed in response to oxidative stress and phagocytic cells

Scedosporium boydii is an opportunistic filamentous fungus which may be responsible for a large variety of infections in both immunocompetent and immunocompromised individuals. This fungus belongs to the Scedosporium apiospermum species complex which usually ranks second among the filamentous fungi colonizing the airways of patients with cystic fibrosis (CF). Species of the S. apiospermum complex are able to chronically colonize the CF airways suggesting pathogenic mechanisms allowing persistence and growth of these fungi in the respiratory tract. Few putative virulence factors have been purified and characterized so far in the S. apiospermum complex including a cytosolic Cu,Zn-superoxide dismutase (SOD) and a monofunctional catalase (catalase A1). Upon microbial infection, host phagocytes release reactive oxygen species (ROS), such as hydrogen peroxide, as part of the antimicrobial response. Catalases are known to protect pathogens against ROS by degradation of the hydrogen peroxide. Here, we identified the S. boydii catalase A1 gene (CATA1) and investigated its expression in response to the environmental conditions encountered in the CF airways and to the oxidative stress. Results showed that S. boydii CATA1 gene expression is not affected by hypoxia, hypercapnia or pH changes. In contrast, CATA1 gene was overexpressed in response to a chemically induced oxidative stress with a relative gene expression 37-fold higher in the presence of 250 μM H(2)O(2), 20-fold higher with 250 μM menadione and 5-fold higher with 2 mM paraquat. Moreover, S. boydii CATA1 gene expression progressively increased upon exposure to activated THP-1-derived macrophages, reaching a maximum after 12 h (26 fold). Activated HL60-derived neutrophils and activated human peripheral blood neutrophils more rapidly induced S. boydii CATA1 gene overexpression, a maximum gene expression level being reached at 75 min (17 fold) and 60 min (15 fold), respectively. In contrast expression of the gene encoding the Cu,Zn-SOD (SODC gene) was not affected by H(2)O(2), menadione, paraquat or in co-culture with phagocytic cells. These results suggest that S. boydii CATA1 gene is highly stimulated by the oxidative burst response whereas SODC gene is constitutively expressed.

Impact of abdominal drainage systems on postoperative complication rates following liver transplantation

BACKGROUND

Depending on the extent of surgery, coagulation status and the number of anastomoses, drains are routinely used during liver transplantation. The aim of this study was to compare different drain types with regard to abdominal complication rates.

METHODS

All consecutive full-size orthotopic liver transplantations (LTX) performed over a 7-year period were included in this retrospective analysis. Abdominal drain groups were divided into open-circuit drains and closed-circuit drains. Data are reported as total number (%) or median (range); for all comparisons a p value <0.05 was considered statistically significant.

RESULTS

A total of 256 LTX [age 56.89 (0.30-75.21) years; MELD 14.5 (7-40)] was included; 56 (21.8 %) patients received an open-circuit Easy Flow Drain (Group 1) and 200 (78.2 %) a closed-circuit Robinson Drainage System (Group 2). For Groups 1 and 2, overall infection rates were 78.6 and 56 % (p = 0.001), abdominal infection rates 50.82 and 21.92 % (p = 0.001), yeast infection rates 37 and 23 % (p = 0.02), abdominal bleeding rates 26.78 and 17 % (p = 0.07), biliary complication rates 14.28 and 13.5 % (p = 0.51), respectively.

CONCLUSIONS

In this retrospective series, open-circuit drains were associated with more abdominal complications, mainly due to intraabdominal infections, than were closed-circuit drains.

Bottom-up modeling approach for the quantitative estimation of parameters in pathogen-host interactions

Opportunistic fungal pathogens can cause bloodstream infection and severe sepsis upon entering the blood stream of the host. The early immune response in human blood comprises the elimination of pathogens by antimicrobial peptides and innate immune cells, such as neutrophils or monocytes. Mathematical modeling is a predictive method to examine these complex processes and to quantify the dynamics of pathogen-host interactions. Since model parameters are often not directly accessible from experiment, their estimation is required by calibrating model predictions with experimental data. Depending on the complexity of the mathematical model, parameter estimation can be associated with excessively high computational costs in terms of run time and memory. We apply a strategy for reliable parameter estimation where different modeling approaches with increasing complexity are used that build on one another. This bottom-up modeling approach is applied to an experimental human whole-blood infection assay for Candida albicans. Aiming for the quantification of the relative impact of different routes of the immune response against this human-pathogenic fungus, we start from a non-spatial state-based model (SBM), because this level of model complexity allows estimating a priori unknown transition rates between various system states by the global optimization method simulated annealing. Building on the non-spatial SBM, an agent-based model (ABM) is implemented that incorporates the migration of interacting cells in three-dimensional space. The ABM takes advantage of estimated parameters from the non-spatial SBM, leading to a decreased dimensionality of the parameter space. This space can be scanned using a local optimization approach, i.e., least-squares error estimation based on an adaptive regular grid search, to predict cell migration parameters that are not accessible in experiment. In the future, spatio-temporal simulations of whole-blood samples may enable timely stratification of sepsis patients by distinguishing hyper-inflammatory from paralytic phases in immune dysregulation.

A virtual infection model quantifies innate effector mechanisms and Candida albicans immune escape in human blood

Candida albicans bloodstream infection is increasingly frequent and can result in disseminated candidiasis associated with high mortality rates. To analyze the innate immune response against C. albicans, fungal cells were added to human whole-blood samples. After inoculation, C. albicans started to filament and predominantly associate with neutrophils, whereas only a minority of fungal cells became attached to monocytes. While many parameters of host-pathogen interaction were accessible to direct experimental quantification in the whole-blood infection assay, others were not. To overcome these limitations, we generated a virtual infection model that allowed detailed and quantitative predictions on the dynamics of host-pathogen interaction. Experimental time-resolved data were simulated using a state-based modeling approach combined with the Monte Carlo method of simulated annealing to obtain quantitative predictions on a priori unknown transition rates and to identify the main axis of antifungal immunity. Results clearly demonstrated a predominant role of neutrophils, mediated by phagocytosis and intracellular killing as well as the release of antifungal effector molecules upon activation, resulting in extracellular fungicidal activity. Both mechanisms together account for almost of C. albicans killing, clearly proving that beside being present in larger numbers than other leukocytes, neutrophils functionally dominate the immune response against C. albicans in human blood. A fraction of C. albicans cells escaped phagocytosis and remained extracellular and viable for up to four hours. This immune escape was independent of filamentation and fungal activity and not linked to exhaustion or inactivation of innate immune cells. The occurrence of C. albicans cells being resistant against phagocytosis may account for the high proportion of dissemination in C. albicans bloodstream infection. Taken together, iterative experiment–model–experiment cycles allowed quantitative analyses of the interplay between host and pathogen in a complex environment like human blood.

Candida albicans is the most important fungal pathogen in nosocomial bloodstream infections. So far little is known about the interplay of different cellular and non-cellular immune mechanisms mediating the protective response against C. albicans in blood. The in vivo scenario of C. albicans infection can be mimicked by human whole-blood infection assays to analyze the innate immune response against this pathogen. These experiments reveal the time-evolution of certain mechanisms while leaving the values of other quantities in the dark. To shed light on quantities that are not experimentally accessible, we exploited the descriptive and predictive power of mathematical models to estimate these parameters. The combination of experiment and theory enabled us to identify and quantify the main course of the immune response against C. albicans in human blood. We quantified the central role of neutrophils in the defence against this fungal pathogen, both directly by phagocytosis and indirectly by secreting antimicrobial factors inducing extracellular killing. Other findings include the distribution of C. albicans cells in neutrophils and monocytes as well as the immune escape of C. albicans cells in the course of infection.

Brazilian guidelines for the management of candidiasis - a joint meeting report of three medical societies: Sociedade Brasileira de Infectologia, Sociedade Paulista de Infectologia and Sociedade Brasileira de Medicina Tropical

Candida infections account for 80% of all fungal infections in the hospital environment, including bloodstream, urinary tract and surgical site infections. Bloodstream infections are now a major challenge for tertiary hospitals worldwide due to their high prevalence and mortality rates. The incidence of candidemia in tertiary public hospitals in Brazil is approximately 2.5 cases per 1000 hospital admissions. Due to the importance of this infection, the authors provide a review of the diversity of the genus Candida and its clinical relevance, the therapeutic options and discuss the treatment of major infections caused by Candida. Each topography is discussed with regard to epidemiological, clinical and laboratory diagnostic and therapeutic recommendations based on levels of evidence.

Role of probiotics in prevention of Candida infection in critically ill children

Candidiasis accounts for 10-20% of bloodstream infections in paediatric intensive care units (PICUs) and a significant increase in morbidity, mortality, and length of hospital stay. Enteric colonisation by Candida species is one of the most important risk factor for invasive candidiasis. The local defence mechanisms may be altered in critically ill patients, thus facilitating Candida overgrowth and candidiasis. Systemic antifungals have been proven to be effective in reducing fungal colonisation and invasive fungal infections, but their use is not without harms. Early restoration or maintenance of intestinal microbial flora using probiotics could be one of the important tools for reducing Candida infection. A few studies have demonstrated that probiotics are able to prevent Candida growth and colonisation in neonates, whereas their role in preventing invasive candidiasis in such patients is still unclear. Moreover, there are no published data on role of probiotics supplementation in the prevention of candidiasis in critically ill children beyond neonatal period. There are gap in our knowledge regarding efficacy, cost effectiveness, risk-benefit potential, optimum dose, frequency and duration of treatment of probiotics in prevention of fungal infections in critically ill children. Studies exploring and evaluating the role of probiotics in prevention of Candida infection in critically ill children are needed.

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.

Localized candidiasis in kidney presented as a mass mimicking renal cell carcinoma

Candida albicans is a ubiquitous fungus and infection of urinary tract by C. albicans can be originated from blood or retrograde infection. We reported a case of localized candidiasis in the kidney presenting as a mass. The patient was a 61-year-old male with a history of type 2 diabetes mellitus and urinary bladder urothelial carcinoma status post radical cystoprostatectomy with a neobladder three years ago. Pathology at that time also showed a prostatic adenocarcinoma (Gleason score 3 + 4) in addition to the high-grade urothelial carcinoma. Three month ago the patient presented with flank pain, chill, and increased white cell counts. Imaging study showed a large renal mass suspicious for a renal cell carcinoma. Radical nephrectomy was performed and found that there was a large pocket of pus in the retroperitoneum around the right kidney during the surgery. Intraoperative abscess cultures were positive for C. albicans. Pathology showed a 13.5 cm necrotic renal mass extending to the perinephric fat. Histologically the tumor showed necrotic granulomatous inflammation. Grocott stain in the surgical specimen was positive for pseudohyphae and yeast forms. The patient was initiated a course of fluconazole postoperatively and was feeling well.

Colonisation in adult patients with nosocomial candidemia

The aim of this prospective study was to investigate the association between Candida spp. isolated from blood culture and the colonisation of different anatomical sites of patients with candidemia, and to evaluate the colonisation dynamics and Pittet's index. Cultures were collected from the different anatomical sites of all the patients within 24 h of diagnosis of candidemia. Molecular similarities between identical species colonised with Candida species were evaluated via karyotyping. The colonisation index, as developed by Pittet et al. was calculated using screening culture results from patients. Among the 40 patients screened for colonisation, 35 (87.5%) had colonisation of at least one anatomical site. Twenty-six (74.3%) of the 35 patients with colonisation in any of the three anatomical sites (respiratory, rectum and urinary sites) were shown to be colonised with the same species that caused candidemia. When the anatomical sites were compared with each other, no significant difference was observed at the species level in terms of colonisation index. The colonisation index (≥ 0.5) positivity rate was 74% in patients with candidemia. The investigation of Candida colonisation of at least three anatomical (respiratory, rectum and urinary) sites could help in the selection of empirical antifungal therapy when nosocomial candidemia is suspected.

The Inflammatory response induced by aspartic proteases of Candida albicans is independent of proteolytic activity

The secretion of aspartic proteases (Saps) has long been recognized as a virulence-associated trait of the pathogenic yeast Candida albicans. In this study, we report that different recombinant Saps, including Sap1, Sap2, Sap3, and Sap6, have differing abilities to induce secretion of proinflammatory cytokines by human monocytes. In particular Sap1, Sap2, and Sap6 significantly induced interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α), and IL-6 production. Sap3 was able to stimulate the secretion of IL-1β and TNF-α. All Saps tested were able to induce Ca(2+) influx in monocytes. Treatment of these Saps with pepstatin A did not have any effect on cytokine secretion, indicating that their stimulatory potential was independent from their proteolytic activity. The capacity of Saps to induce inflammatory cytokine production was also independent from protease-activated receptor (PAR) activation and from the optimal pH for individual Sap activity. The interaction of Saps with monocytes induced Akt activation and phosphorylation of IκBα, which mediates translocation of NF-κB into the nucleus. Overall, these results suggest that individual Sap proteins can induce an inflammatory response and that this phenomenon is independent from the pH of a specific host niche and from Sap enzymatic activity. The inflammatory response is partially dependent on Sap denaturation and is triggered by the Akt/NF-κB activation pathway. Our data suggest a novel, activity-independent aspect of Saps during interactions of C. albicans with the host.

Exposure of the yeast Candida albicans to the anti-neoplastic agent adriamycin increases the tolerance to amphotericin B

Cancer patients experience a high incidence of fungal infections due to their immuno-suppressed condition. This work has investigated the interaction of an anti-neoplastic agent, adriamycin (doxorubicin), with the yeast Candida albicans and examined whether this drug altered the susceptibility of the yeast to amphotericin B – an anti-fungal agent used for the treatment of systemic fungal infections in cancer patients. Exposure to adriamycin for 24 h increased the growth of C. albicans and increased the tolerance to amphotericin B by a small, but statistically significant, extent. Growth in adriamycin-supplemented medium suppressed the respiration rate of C. albicans, which resulted in a decrease in the ergosterol content of the fungal cell membrane. The tolerance to amphotericin B was lost after exposure to adriamycin for 48 h, which coincided with a restoration in the respiration rate and the ergosterol content of the fungal cell membrane. This work demonstrated that short-term exposure (24 h) to adriamycin increased the tolerance of C. albicans for amphotericin B, which may be mediated by a decrease in the ergosterol content as a result of an adriamycin-induced disruption of oxidative phosphorylation.

Synthesis, characterization and biocidal activity of new organotin complexes of 2-(3-oxocyclohex-1-enyl)benzoic acid

The reaction of 1,3-cyclohexadione with 2-aminobenzoic acid has produced the 2-(3-oxocyclohex-1-enyl)benzoic acid (HOBz). Subsequent reactions of the ligand with organotin chlorides led to [Me(2)Sn(OBz)O](2) (1), [Bu(2)Sn(OBz)O](2) (2), [Ph(2)Sn(OBz)O](2) (3), [Me(3)Sn(OBz)] (4), [Bu(3)Sn(OBz)] (5) and [Ph(3)Sn(OBz)] (6). All complexes have been fully characterized. In addition the structure of complexes (2) and (4) have been authenticated by X-ray crystallography. The biological activity of all derivatives has been screened against Cryptococcus neoformans and Candida albicans. In addition we have performed toxicological testes employing human kidney cell. The complexes (3), (5) and (6) displayed the best values of inhibition of the fungus growing, superior to ketoconazole. Compound (5) presented promising results in view of the antifungal and cytotoxicity assays.

Invasive candidiasis in pediatric intensive care units

Candidemia and disseminated candidiasis are major causes of morbidity and mortality in hospitalized patients especially in the intensive care units (ICU). The incidence of invasive candidasis is on a steady rise because of increasing use of multiple antibiotics and invasive procedures carried out in the ICUs. Worldwide there is a shifting trend from C. albicans towards non albicans species, with an associated increase in mortality and antifungal resistance. In the ICU a predisposed host in one who is on broad spectrum antibiotics, parenteral nutrition, and central venous catheters. There are no pathognomonic signs or symptoms. The clinical clues are: unexplained fever or signs of severe sepsis or septic shock while on antibiotics, multiple, non-tender, nodular erythematous cutaneous lesions. The spectrum of infection with candida species range from superficial candidiasis of the skin and mucosa to more serious life threatening infections. Treatment of candidiasis involves removal of the most likely source of infection and drug therapy to speed up the clearance of infection. Amphotericin B remains the initial drug of first choice in hemodynamically unstable critically ill children in the wake of increasing resistance to azoles. Evaluation of newer antifungal agents and precise role of prophylactic therapy in ICU patients is needed.

Avoiding pitfalls: what an endoscopist should know in liver transplantation--part II

Over the last decade the number of patients undergoing transplantation has increased. At the same time, effective peri- and postoperative care and better surgical techniques have resulted in greater numbers of recipients achieving long-term survival. Identification and effective management in the form of adequate treatment is essential, since any delay in diagnosis or treatment may result in graft loss or serious threat to patient's life. Various aspects of endoscopic findings that can be commonly encountered among liver transplant recipients are discussed herein. Topics include: persistent and/or recurrent esophageal varices, reflux, Candida or cytomegalovirus (CMV) esophagitis, esophageal neoplasms, posttransplant peptic ulcer, biliary complications, posttransplant lymphoproliferative disorder (PTLD), Kaposi's sarcoma, CMV colitis and inflammatory bowel disease, colonic neoplasms, Clostridium difficile infection, and graft versus host disease (GVHD).

Polymicrobial bloodstream infection in pediatric patients: risk factors, microbiology, and antimicrobial management

BACKGROUND

Few studies focus on polymicrobial bloodstream infections (PBSIs) in children. In previous reports, children with PBSI frequently had complex underlying medical conditions and a high incidence of specific microorganisms, but systematic evaluation with controls was not performed. We postulated that specific clinical risk factors are associated with an increased risk of PBSI, and that illness may be more severe with these infections. Additionally, we suspected that routine empiric antimicrobial therapy may frequently be inadequate to treat the variety of pathogens in PBSI.

METHODS

Positive blood cultures from 1998 to 2004 were reviewed. Patients whose cultures grew >1 organism were age-matched with monomicrobial bloodstream infection controls. Records were reviewed to compare their underlying medical conditions, organisms isolated, adequacy of therapy, and clinical characteristics of illness.

RESULTS

Twenty-nine episodes of PBSI were identified in 18 subjects. PBSI patients were more likely to have chronic medical conditions, chronic gastrointestinal pathology, central venous catheters, and to be receiving parenteral nutrition than controls. Pathogens found more commonly in PBSI episodes included Enterococcus spp., coagulase-negative staphylococci, and Candida spp. Empiric antimicrobial therapy was less likely to be adequate in patients with PBSI. PBSI patients were hospitalized longer, required longer intensive care and had prolonged bloodstream infection. Subjects with PBSI had prolonged duration of fever and had higher degrees of sepsis than controls.

CONCLUSIONS

Chronic medical conditions, particularly gastrointestinal disease, are risk factors for PBSIs. Because clinical illness may be more severe, alteration of the empiric antimicrobial regimen should be considered in some of these patients.

Is there a serious risk of resistance development to azoles among fungi due to the widespread use and long-term application of azole antifungals in medicine?

It is well known that development of antibiotic resistance in bacteria is not a matter of if but of when. Recently, azoles have been recommended for long-term prophylaxis of invasive fungal infections; hence, it could be argued that fungi also will become resistant to these agents. However, fungi are different from bacteria in several critical points. Bacteria display several resistance mechanisms: alteration of the target, limited access to the target and modification/inactivation of the antibacterial compound. In fungi some mechanisms of resistance to azoles are also known; with azoles for example, alterations of the 14alpha-demethylase target, as well as efflux pumps. It has been observed that these phenotypes develop in yeast populations either due to mutations or to selection processes. However, enzymes which destroy azoles are not found. Furthermore, a horizontal transfer of genes coding resistance traits does not occur in fungi, which means that an explosive expansion of resistances is unlikely to occur, especially in moulds. Indeed, in epidemiologic studies on human and environmental isolates there is convincing evidence that azole resistance is quite uncommon.