Risk of resistance associated with fluconazole prophylaxis: systematic review

Early- and late-onset candidemia in very low birth weight infants in the Korean neonatal network, 2013-2017

BACKGROUND

Candidiasis is a critical infection that is associated with very low birth weight (VLBW; <1500 g). This study investigated the characteristics and clinical presentation of candidiasis in Korean VLBW infants according to the onset of candidemia.

METHODS

All VLBW infants with candidemia, defined as blood culture-positive candidiasis and registered in a multicenter database with data from 70 neonatal units of the Korean Neonatal Network between 2013 and 2017, were included in this study. Early-onset candidemia (EOC; ≤10 days) and late-onset candidemia (LOC; >10 days) were analyzed. The demographic characteristics, clinical presentations, and outcomes of candidemia were also determined.

RESULTS

The overall incidence of candidemia was 2% (209/10,397) and 4% (173/3934) in VLBW and extremely very low birth weight (ELBW; <1000 g) infants, respectively. In ELBW infants, gestational age was significantly younger at EOC than at LOC (P = 0.015). Cesarean section, respiratory distress syndrome, severe bronchopulmonary disease, pulmonary hemorrhage, prior-bacteremia, neonatal seizures, and periventricular leukomalacia were significantly more common in the LOC group than in the EOC group (P < 0.05). The duration of invasive ventilation, total parenteral nutrition, and hospital stay were significantly longer in the LOC group than in the EOC group (P < 0.05). Most infections were caused by Candida spp. (91.8%). The mortality rate of ELBW infants with candidemia was 41%, which was higher than that of those without candidemia (29%) (P < 0.001). Mortality due to infection was also higher in infants with candidemia (55%) than in those without candidemia (15%) (P < 0.001); however, there were no significant differences between the EOC and LOC groups.

CONCLUSIONS

LOC was more common than EOC in VLBW infants. Considering the risk factors of LOC, active weaning from invasive ventilators and aggressive enteral feeding are required to decrease LOC. Furthermore, preventing candidemia is necessary to reduce mortality in VLBW infants.

Antifungal Activity and Type of Interaction of Melissa officinalis Essential Oil with Antimycotics against Biofilms of Multidrug-Resistant Candida Isolates from Vulvovaginal Mucosa

(1) Background: Vulvovaginal candidosis (VVC) is a major therapy issue due to its high resistance rate and virulence factors such as the ability to form biofilms. The possibility of combining commonly used antifungals with natural products might greatly improve therapeutic success. (2) Methods: A total of 49 vulvovaginal isolates, causative agents of recurrent VVC, were tested for their susceptibility to fluconazole, nystatin, and Melissa officinalis essential oil (MOEO). This examination included testing the antibiofilm potential of antifungals and MOEO and the determination of their types of interaction with mature biofilms. (3) Results: Antimicrobial testing showed that 94.4% of the Candida albicans isolates and all the Candida krusei isolates were resistant to fluconazole, while all strains showed resistance to nystatin. The same strains were susceptible to MOEO in 0.156-2.5 mg/mL concentrations. Additionally, the results revealed very limited action of fluconazole, while nystatin and MOEO reduced the amount of biofilm formed by as much as 17.7% and 4.6%, respectively. Testing of the combined effect showed strain-specific synergistic action. Furthermore, the lower concentrations exhibited antagonistic effects even in cases where synergism was detected. (4) Conclusions: This study showed that MOEO had a very good antibiofilm effect. However, combining MOEO with antimycotics demonstrated that the type of action depended on the choice of antifungal drugs as well as the applied concentration.

Intravaginal Gel for Sustained Delivery of Occidiofungin and Long-Lasting Antifungal Effects

Fungal infections are caused by opportunistic pathogens that can be life threatening or debilitating. Candida spp. are becoming increasingly resistant to current clinically approved antifungal therapeutics. Candida infections afflict not only immunosuppressed but also immunocompetent individuals. Recurrent vulvovaginal candidiasis (RVVC) is a disease that afflicts 5-9% of women. Occidiofungin is a novel cyclic peptide that has a broad spectrum of antifungal activity with a novel fungicidal mechanism of action. A gel formulation containing occidiofungin (OCF001) is being developed for use to treat vulvovaginal candidiasis. The formulated gel for intravaginal application used hydroxyethyl cellulose as the primary gelling agent and hydroxypropyl β-cyclodextrin as a solubilizing agent for occidiofungin. Franz cells and LC-MS/MS were used to determine the rate of drug substance diffusion in the gel formulation. The formulation was tested in an ex vivo mouse skin efficacy study, and the safety was tested following repeat intravaginal administration in rabbits. In this study, the gel formulation was shown to reduce the drug substance rate of diffusion across a skin memetic membrane. The study showed that the formulation extends exposure time to inhibitory concentrations of occidiofungin over a 24-h period and supports a single daily application for the treatment of RVVC.

Should Preventive Antifungal Treatment Be Given to Patients With Abdominal Contamination in the Intensive Care Unit?

Background Intra-abdominal contamination is a critical risk factor for candidemia. Because of the high mortality of candidemia and delayed results of cultures, preventive antifungal (AF) treatment can be administered. Especially in the intensive care unit (ICU), it may be necessary to determine the preventive AF approach due to the poor clinical condition of the patients. However, this practice is not standard among clinicians, and it is controversial whether it is beneficial or not. This study aimed to evaluate the effects of different AF treatment approaches (prophylactic, empirical, and culture-directed) on mortality, development of candidemia, and length of hospital stay in these patients. The primary outcome of the study was mortality, and the secondary outcomes were the development of candidemia and length of hospital stay. Methodology This is a retrospective, single-center, cohort study. Adult patients who were hospitalized in the ICU with the diagnosis of intra-abdominal contamination between January 1, 2017, and December 31, 2020, were reviewed retrospectively from electronic hospital records and Infectious Diseases ICU patient follow-up forms. Age, gender, comorbid diseases, the reason for hospitalization, history of surgical operation, surgical procedure type, length of hospital stay, culture results of blood and intraoperative intra-abdominal samples (pus, peritoneal fluid, abscess), type of AF agents, and mortality status of the patients were recorded. Furthermore, white blood cell (WBC) count, platelet count, C-reactive protein (CRP) level, procalcitonin (PCT) level, and serum albumin levels in blood samples taken on three different days (the day of diagnosis, the day of operation, and the day of candidemia) were examined. The patients were grouped as without AF, receiving prophylactic AF, receiving empirical AF, and receiving culture-directed AF. Additionally, the study population was evaluated by dividing it into two groups, namely, those who developed candidemia and those who did not. The patients were evaluated regarding the development of candidemia, AF treatment approach, length of hospital stay, and mortality. Results A total of 196 patients were included in the study. Candidemia was determined in 31.6% of the patients. Candidemia was more common in patients with a history of previous surgery and presenting with acute abdominal pain than other causes. It was determined that 70% of the patients who developed candidemia had perforation, with the most common being colonic perforation. The hospital stay was longer in patients with candidemia than without candidemia (47.9 vs. 22.4 days; p < 0.001). When empirical and prophylactic AF recipients were compared, there was no difference in mortality and length of hospital stay. Prolongation of the time to empirical treatment after perforation/leak was associated with increased candidemia (p = 0.004). Furthermore, patients with a waiting time of ≥4.5 days until surgical operation were at a higher risk of developing candidemia. Conclusions Although the study did not demonstrate a difference in terms of reducing mortality, it was concluded that preventive AF therapy can be administered to reduce the risk of candidemia and hospitalization duration, especially in patients with a history of previous surgical operations and abdominal contamination with a prolonged waiting period until the surgical operation.

Reversal of azole resistance in Candida albicans by oridonin

OBJECTIVES

Candida albicans is a yeast that causes fungal infections with high mortality and is typically resistant to azole drugs. To overcome this resistance, we explored the combined use of oridonin (ORI) and three azole drugs, namely fluconazole (FLC), itraconazole (ITR) and voriconazole (VOR). Azole-resistant C. albicans strains were obtained from cancer patients and the reversal of drug resistance in these strains was investigated.

METHODS

The synergistic antifungal activity of ORI and azole drugs was measured by checkerboard microdilution and time-kill assays. The resistance reversal mechanisms, namely inhibition of drug efflux and induction of apoptosis, were investigated by flow cytometry. Expression levels of the efflux pump-related genesCDR1 and CDR2 were assessed by RT-qPCR.

RESULTS

The efflux pump inhibition assay with ORI showed that the minimum inhibitory concentrations (MICs) of FLC (128-fold), ITR (64-fold) and VOR (250-fold) decreased significantly. Upregulation of genes encodingCDR1 and CDR2 was confirmed in the resistant strain. The sensitising effect of ORI on FLC in the treatment of C. albicans also included the promotion of apoptosis.

CONCLUSION

We demonstrated that combining azoles with ORI exerted potent synergism and that ORI could promote sensitisation to azoles in azole-resistantC. albicans. The discovery that ORI can effectively inhibit drug efflux and promote apoptosis may provide new insights and therapeutic strategies to overcome increasing azole resistance in C. albicans.

[Efficacy and safety of fluconazole in prophylaxis of invasive fungal infections in very low birth weight infants: a Meta analysis]

OBJECTIVE

To assess the efficacy and safety of fluconazole in the prophylaxis of invasive fungal infection in very low birth weight (VLBW) infants.

METHODS

Databases including PubMed, Embase, the Cochrane Library, Wanfang Data, Weipu, and CNKI were searched for randomized controlled trials (RCTs) of prophylactic fluconazole in VLBW infants. Review Manager 5.3 software was used to perform a Meta analysis of the included studies.

RESULTS

A total of 12 RCTs were included, involving 1 679 VLBW infants. The Meta analysis showed that prophylactic fluconazole significantly reduced the incidence of invasive fungal infection (RR=0.44, 95%CI: 0.27-0.71, P<0.001), the incidence of fungal colonization (RR=0.31, 95%CI: 0.24-0.40, P<0.001), and the mortality during hospitalization (RR=0.74, 95%CI: 0.58-0.94, P=0.01) compared with the control group. There were no significant differences between VLBW infants using different doses of fluconazole in the incidence of invasive fungal infection and fungal colonization (P>0.05). No significant differences were found in the incidence of fluconazole resistance and complications between the fluconazole and control groups (P>0.05).

CONCLUSIONS

Prophylactic fluconazole can effectively and safely prevent invasive fungal infection in VLBW infants, even at a small dose.

Candida albicans Antifungal Resistance and Tolerance in Bloodstream Infections: The Triad Yeast-Host-Antifungal

Candida albicans represents the most frequent isolated yeast from bloodstream infections. Despite the remarkable progress in diagnostic and therapeutic approaches, these infections continue to be a critical challenge in intensive care units worldwide. The economic cost of bloodstream fungal infections and its associated mortality, especially in debilitated patients, remains unacceptably high. Candida albicans is a highly adaptable microorganism, being able to develop resistance following prolonged exposure to antifungals. Formation of biofilms, which diminish the accessibility of the antifungal, selection of spontaneous mutations that increase expression or decreased susceptibility of the target, altered chromosome abnormalities, overexpression of multidrug efflux pumps and the ability to escape host immune defenses are some of the factors that can contribute to antifungal tolerance and resistance. The knowledge of the antifungal resistance mechanisms can allow the design of alternative therapeutically options in order to modulate or revert the resistance. We have focused this review on the main factors that are involved in antifungal resistance and tolerance in patients with C. albicans bloodstream infections.

Primary antifungal prophylaxis for cryptococcal disease in HIV-positive people

BACKGROUND

Cryptococcal disease remains one of the main causes of death in HIV-positive people who have low cluster of differentiation 4 (CD4) cell counts. Currently, the World Health Organization (WHO) recommends screening HIV-positive people with low CD4 counts for cryptococcal antigenaemia (CrAg), and treating those who are CrAg-positive. This Cochrane Review examined the effects of an approach where those with low CD4 counts received regular prophylactic antifungals, such as fluconazole.

OBJECTIVES

To assess the efficacy and safety of antifungal drugs for the primary prevention of cryptococcal disease in adults and children who are HIV-positive.

SEARCH METHODS

We searched the CENTRAL, MEDLINE PubMed, Embase OVID, CINAHL EBSCOHost, WHO International Clinical Trials Registry Platform (WHO ICTRP), ClinicalTrials.gov, conference proceedings for the International AIDS Society (IAS) and Conference on Retroviruses and Opportunistic Infections (CROI), and reference lists of relevant articles up to 31 August 2017.

SELECTION CRITERIA

Randomized controlled trials of adults and children, who are HIV-positive with low CD4 counts, without a current or prior diagnosis of cryptococcal disease that compared any antifungal drug taken as primary prophylaxis to placebo or standard care.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and risk of bias, and extracted and analysed data. The primary outcome was all-cause mortality. We summarized all outcomes using risk ratios (RR) with 95% confidence intervals (CI). Where appropriate, we pooled data in meta-analyses. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

Nine trials, enrolling 5426 participants, met the inclusion criteria of this review. Six trials administered fluconazole, while three trials administered itraconazole.Antifungal prophylaxis may make little or no difference to all-cause mortality (RR 1.07, 95% CI 0.80 to 1.43; 6 trials, 3220 participants; low-certainty evidence). For cryptococcal specific outcomes, prophylaxis probably reduces the risk of developing cryptococcal disease (RR 0.29, 95% CI 0.17 to 0.49; 7 trials, 5000 participants; moderate-certainty evidence), and probably reduces deaths due to cryptococcal disease (RR 0.29, 95% CI 0.11 to 0.72; 5 trials, 3813 participants; moderate-certainty evidence). Fluconazole prophylaxis may make no clear difference to the risk of developing clinically resistant Candida disease (RR 0.93, 95% CI 0.56 to 1.56; 3 trials, 1198 participants; low-certainty evidence); however, there may be an increased detection of fluconazole-resistant Candida isolates from surveillance cultures (RR 1.25, 95% CI 1.00 to 1.55; 3 trials, 539 participants; low-certainty evidence). Antifungal prophylaxis was generally well-tolerated with probably no clear difference in the risk of discontinuation of antifungal prophylaxis compared with placebo (RR 1.01, 95% CI 0.91 to 1.13; 4 trials, 2317 participants; moderate-certainty evidence). Antifungal prophylaxis may also make no difference to the risk of having any adverse event (RR 1.07, 95% CI 0.88 to 1.30; 4 trials, 2317 participants; low-certainty evidence), or a serious adverse event (RR 1.08, 95% CI 0.83 to 1.41; 4 trials, 888 participants; low-certainty evidence) when compared to placebo or standard care.

AUTHORS' CONCLUSIONS

Antifungal prophylaxis reduced the risk of developing and dying from cryptococcal disease. Therefore, where CrAG screening is not available, antifungal prophylaxis may be used in patients with low CD4 counts at diagnosis and who are at risk of developing cryptococcal disease.

Increasing candidaemia incidence from 2004 to 2015 with a shift in epidemiology in patients preexposed to antifungals

Candidaemia is an important health problem in immunocompromised patients with an epidemiology varying with region, period and patient population involved. The occurrence of candidaemia and the associated species distribution over a 12-year period at a large tertiary care centre in Belgium were analysed. The trend in incidence in the intensive care units (ICUs) and non-ICUs was investigated as well as the influence of antifungal exposure on the species distribution. From 2004 until 2015, 865 candidaemia episodes occurred in 826 patients at the University Hospitals Leuven. Candida albicans (59%) remained the most important cause of candidaemia, followed by C. glabrata (22.4%) and C. parapsilosis (8%). The mean incidence in the whole hospital was 1.48 per 10 000 patient days (PD). The incidence in ICUs increased reaching up to 10.7 per 10 000 PD whereas in the non-ICUs, the incidence decreased. Prior exposure to fluconazole and echinocandins was associated with candidaemia caused by less susceptible species. Candidaemia incidence increased in the whole hospital, driven by ICUs. Surveillance of candidaemia epidemiology on a local scale is of high value to guide empirical treatment strategies.

Candidemia in the Neonatal Intensive Care Unit: A Retrospective, Observational Survey and Analysis of Literature Data

We evaluated the epidemiology of Candida bloodstream infections in the neonatal intensive care unit (NICU) of an Italian university hospital during a 9-year period as a means of quantifying the burden of infection and identifying emerging trends. Clinical data were searched for in the microbiological laboratory database. For comparative purposes, we performed a review of NICU candidemia. Forty-one candidemia cases were reviewed (overall incidence, 3.0 per 100 admissions). Candida parapsilosis sensu stricto (58.5%) and C. albicans (34.1%) were the most common species recovered. A variable drift through years was observed; in 2015, 75% of the cases were caused by non-albicans species. The duration of NICU hospitalization of patients with non-albicans was significantly longer than in those with C. albicans (median days, 10 versus 12). Patients with non-albicans species were more likely to have parenteral nutrition than those with C. albicans (96.3% versus 71.4%). Candida albicans was the dominant species in Europe and America (median, 55% and 60%; resp.); non-albicans species predominate in Asia (75%). Significant geographic variation is evident among cases of candidemia in different parts of the world, recognizing the importance of epidemiological data to facilitate the treatment.

Vetiver Essential Oil in Cosmetics: What Is New?

Background: Vetiver is a key ingredient for the perfume industry nowadays. However, with the constant and rapid changes of personal tastes, this appeal could vanish and this sector could decline quite quickly. New dissemination paths need to be found to tap this valuable resource. Methods: In this way, its potential use in cosmetics either as an active ingredient per se (with cosmeceutical significance or presenting antimicrobial activity) has hence been explored in vitro. Results: In this contribution, we demonstrated that vetiver essential oil displays no particularly significant and innovative cosmetic potential value in formulations apart from its scent already largely exploited. However, evaluated against twenty bacterial strains and two Candida species using the in vitro microbroth dilution method, vetiver oil demonstrated notably some outstanding activities against Gram-positive strains and against one Candida glabrata strain. Conclusions: Based on these findings, vetiver essential oil appears to be an appropriate aspirant for the development of an antimicrobial agent for medicinal purposes and for the development of a cosmetic ingredient used for its scent and displaying antimicrobial activity as an added value.

Problematic Dichotomization of Risk for Intensive Care Unit (ICU)-Acquired Invasive Candidiasis: Results Using a Risk-Predictive Model to Categorize 3 Levels of Risk From a Multicenter Prospective Cohort of Australian ICU Patients

BACKGROUND

 Delayed antifungal therapy for invasive candidiasis (IC) contributes to poor outcomes. Predictive risk models may allow targeted antifungal prophylaxis to those at greatest risk.

METHODS

 A prospective cohort study of 6685 consecutive nonneutropenic patients admitted to 7 Australian intensive care units (ICUs) for ≥72 hours was performed. Clinical risk factors for IC occurring prior to and following ICU admission, colonization with Candida species on surveillance cultures from 3 sites assessed twice weekly, and the occurrence of IC ≥72 hours following ICU admission or ≤72 hours following ICU discharge were measured. From these parameters, a risk-predictive model for the development of ICU-acquired IC was then derived.

RESULTS

 Ninety-six patients (1.43%) developed ICU-acquired IC. A simple summation risk-predictive model using the 10 independently significant variables associated with IC demonstrated overall moderate accuracy (area under the receiver operating characteristic curve = 0.82). No single threshold score could categorize patients into clinically useful high- and low-risk groups. However, using 2 threshold scores, 3 patient cohorts could be identified: those at high risk (score ≥6, 4.8% of total cohort, positive predictive value [PPV] 11.7%), those at low risk (score ≤2, 43.1% of total cohort, PPV 0.24%), and those at intermediate risk (score 3-5, 52.1% of total cohort, PPV 1.46%).

CONCLUSIONS

 Dichotomization of ICU patients into high- and low-risk groups for IC risk is problematic. Categorizing patients into high-, intermediate-, and low-risk groups may more efficiently target early antifungal strategies and utilization of newer diagnostic tests.

FREQUENCY OF Candida SPECIES IN A TERTIARY CARE HOSPITAL IN TRIANGULO MINEIRO, MINAS GERAIS STATE, BRAZIL

Infections by Candida species are a high-impact problem in public health due to their wide incidence in hospitalized patients. The goal of this study was to evaluate frequency, susceptibility to antifungals, and genetic polymorphism of Candida species isolated from clinical specimens of hospitalized patients. The Candida isolates included in this study were obtained from blood cultures, abdominal fluids, and central venous catheters (CVC) of hospitalized patients at the Clinical Hospital of the Federal University of Uberlândia during the period of July 2010 - June 2011. Susceptibility tests were conducted by the broth microdilution method. The RAPD-PCR tests used employed initiator oligonucleotides OPA09, OPB11, and OPE06. Of the 63 Candida isolates, 18 (28.5%) were C. albicans, 20 (31.7%) were C. parapsilosis complex species, 14 (22.2%) C. tropicalis, four (6.4%) C. glabrata, four (6.4%) C. krusei, two (3.3%) C. kefyr, and one (1.6%) C. lusitaniae. In vitro resistance to amphotericin B was observed in 12.7% of isolates. In vitroresistance to azoles was not detected, except for C. krusei. The two primers, OPA09 and OPB11, were able to distinguish different species. Isolates of C. albicans and C. parapsilosis complex species presented six and five clusters, respectively, with the OPA09 marker by RAPD-PCR, showing the genetic variability of the isolates of those species. It was concluded that members of the C. parapsilosis complex were the most frequent species found, and most isolates were susceptible to the antifungals amphotericin B, flucozanole, and itraconazole. High genetic polymorphisms were observed for isolates of C. albicans and C. parapsilosis complex species, mainly with the OPA09 marker.

Prophylactic systemic antifungal agents to prevent mortality and morbidity in very low birth weight infants

BACKGROUND

Invasive fungal infection is an important cause of mortality and morbidity in very preterm and very low birth weight infants. Early diagnosis is difficult and treatment is often delayed. Systemically absorbed antifungal agents (usually azoles) are increasingly used as prophylaxis against invasive fungal infection in this population.

OBJECTIVES

To assess the effect of prophylactic systemic antifungal therapy on mortality and morbidity in very preterm or very low birth weight infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2015, Issue 8), MEDLINE, EMBASE, and CINAHL (to May 2015), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised controlled trials or quasi-randomised controlled trials that compared the effect of prophylactic systemic antifungal therapy versus placebo or no drug or another antifungal agent or dose regimen in very low birth weight infants.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by two review authors.

MAIN RESULTS

We identified 15 eligible trials enrolling a total of 1690 infants. Ten trials (1371 infants) compared systemic antifungal prophylaxis versus placebo or no drug. These trials were generally of good methodological quality. Meta-analysis found a statistically significant reduction in the incidence of invasive fungal infection (typical risk ratio (RR) 0.43, 95% confidence interval (CI) 0.31 to 0.59; risk difference (RD) -0.09, 95% CI -0.12 to -0.06). The average incidence of invasive fungal infection in the control groups of the trials (16%) was much higher than that generally reported from large cohort studies. Meta-analysis did not find a statistically significant difference in the risk of death prior to hospital discharge (typical RR 0.79, 95% CI 0.61 to 1.02; typical RD -0.04, 95% CI -0.07 to 0.00). Very limited data on long-term neurodevelopmental outcomes were available. Three trials that compared systemic versus oral or topical non-absorbed antifungal prophylaxis did not detect any statistically significant effects on invasive fungal infection or mortality. Two trials that compared different dose regimens of prophylactic intravenous fluconazole did not detect any significant differences in infection rates or mortality.

AUTHORS' CONCLUSIONS

Prophylactic systemic antifungal therapy reduces the incidence of invasive fungal infection in very preterm or very low birth weight infants. This finding should be interpreted and applied cautiously since the incidence of invasive fungal infection was very high in the control groups of many of the included trials. Meta-analysis does not demonstrate a statistically significant effect on mortality. There are currently only limited data on the long-term neurodevelopmental consequences for infants exposed to this intervention. In addition, there is a need for further data on the effect of the intervention on the emergence of organisms with antifungal resistance.

Prophylactic oral/topical non-absorbed antifungal agents to prevent invasive fungal infection in very low birth weight infants

BACKGROUND

Invasive fungal infection is an important cause of mortality and morbidity in very preterm or very low birth weight infants. Uncertainty exists about the effect of prophylactic oral/topical non-absorbed antifungals to reduce mucocutaneous colonisation and so limit the risk of invasive fungal infection in this population.

OBJECTIVES

To assess the effect of prophylactic oral/topical non-absorbed antifungal therapy on the incidence of invasive fungal infection, mortality and morbidity in very preterm or very low birth weight infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL: The Cochrane Library, 2015, Issue 7), MEDLINE, EMBASE, and CINAHL (to May 2015), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised controlled trials or quasi-randomised controlled trials that compared the effect of prophylactic oral/topical non-absorbed antifungal therapy versus placebo or no drug or another antifungal agent or dose regimen in very preterm or very low birth weight infants.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group with separate evaluation of trial quality and data extraction by two review authors.

MAIN RESULTS

Four trials, in which a total of 1800 infants participated, compared oral/topical non-absorbed antifungal prophylaxis (nystatin or miconazole) with placebo or no drug. These trials had various methodological weaknesses including quasi-randomisation, lack of allocation concealment, and lack of blinding of intervention and outcomes assessment. The incidence of invasive fungal infection was very high in the control groups of three of these trials. Meta-analysis found a statistically significant reduction in the incidence of invasive fungal infection (typical risk ratio 0.20, 95% confidence interval 0.14 to 0.27; risk difference -0.18, -0.21 to -0.15) but substantial statistical heterogeneity was present. We did not find a statistically significant effect on mortality (typical risk ratio 0.87, 0.72 to 1.05; risk difference -0.03, -0.06 to 0.01). None of the trials assessed posthospital discharge outcomes. Three trials (N = 326) assessed the effect of oral/topical non-absorbed versus systemic antifungal prophylaxis. Meta-analyses did not find any statistically significant differences in the incidences of invasive fungal infection or all-cause mortality.

AUTHORS' CONCLUSIONS

The finding of a reduction in risk of invasive fungal infection in very low birth weight infants treated with oral/topical non-absorbed antifungal prophylaxis should be interpreted cautiously because of methodological weaknesses in the included trials. Further large randomised controlled trials in current neonatal practice settings are needed to resolve this uncertainty. These trials might compare oral/topical non-absorbed antifungal agents with placebo, with each other, or with systemic antifungal agents and should include an assessment of effect on long-term neurodevelopmental outcomes.

Comparative Study on the Efficiency of the Photodynamic Inactivation of Candida albicans Using CdTe Quantum Dots, Zn(II) Porphyrin and Their Conjugates as Photosensitizers

The application of fluorescent II-VI semiconductor quantum dots (QDs) as active photosensitizers in photodymanic inactivation (PDI) is still being evaluated. In the present study, we prepared 3 nm size CdTe QDs coated with mercaptosuccinic acid and conjugated them electrostatically with Zn(II) meso-tetrakis (N-ethyl-2-pyridinium-2-yl) porphyrin (ZnTE-2-PyP or ZnP), thus producing QDs-ZnP conjugates. We evaluated the capability of the systems, bare QDs and conjugates, to produce reactive oxygen species (ROS) and applied them in photodynamic inactivation in cultures of Candida albicans by irradiating the QDs and testing the hypothesis of a possible combined contribution of the PDI action. Tests of in vitro cytotoxicity and phototoxicity in fibroblasts were also performed in the presence and absence of light irradiation. The overall results showed an efficient ROS production for all tested systems and a low cytotoxicity (cell viability >90%) in the absence of radiation. Fibroblasts incubated with the QDs-ZnP and subjected to irradiation showed a higher cytotoxicity (cell viability <90%) depending on QD concentration compared to the bare groups. The PDI effects of bare CdTe QD on Candida albicans demonstrated a lower reduction of the cell viability (~1 log10) compared to bare ZnP which showed a high microbicidal activity (~3 log10) when photoactivated. The QD-ZnP conjugates also showed reduced photodynamic activity against C. albicans compared to bare ZnP and we suggest that the conjugation with QDs prevents the transmembrane cellular uptake of the ZnP molecules, reducing their photoactivity.

Clinical pharmacology of antifungal agents to overcome drug resistance in pediatric patients

INTRODUCTION

Antifungal resistance is an emerging problem that increases morbidity and mortality in immunosuppressed pediatric patients, who suffer from invasive fungal diseases. Optimal pharmacological management is critical for the successful treatment of invasive fungal infections by resistant strains.

AREAS COVERED

This paper reviews the mechanisms of resistance of different classes of antifungal agents and the current understanding of pediatric antifungal pharmacology for overcoming antifungal resistance in children based on laboratory and clinical studies in the English literature. The therapeutic choices against fungal pathogens with intrinsic or acquired resistance are further reviewed.

EXPERT OPINION

There is a paucity of data in the pediatric population regarding the epidemiology of the resistant organisms to different antifungal agents. It is also unknown if there are more prevalent molecular mechanisms that promote antifungal resistance. Selection and dosages of the most effective antifungal agent for overcoming the antifungal resistance is crucial. However, there are limited studies guiding the optimal dosage and duration of treatment for management of emergent antifungal resistance. Further studies are warranted to elucidate the optimal pharmacology of the current antifungal agents against resistant organisms and to advance the development of new antifungal agents.

New insights into innate immune control of systemic candidiasis

Systemic infection caused by Candida species is the fourth leading cause of nosocomial bloodstream infection in modern hospitals and carries high morbidity and mortality despite antifungal therapy. A recent surge of immunological studies in the mouse models of systemic candidiasis and the parallel discovery and phenotypic characterization of inherited genetic disorders in antifungal immune factors that are associated with enhanced susceptibility or resistance to the infection have provided new insights into the cellular and molecular basis of protective innate immune responses against Candida. In this review, the new developments in our understanding of how the mammalian immune system responds to systemic Candida challenge are synthesized and important future research directions are highlighted.

Development and validation of a risk model for identification of non-neutropenic, critically ill adult patients at high risk of invasive Candida infection: the Fungal Infection Risk Evaluation (FIRE) Study

BACKGROUND

There is increasing evidence that invasive fungal disease (IFD) is more likely to occur in non-neutropenic patients in critical care units. A number of randomised controlled trials (RCTs) have evaluated antifungal prophylaxis in non-neutropenic, critically ill patients, demonstrating a reduction in the risk of proven IFD and suggesting a reduction in mortality. It is necessary to establish a method to identify and target antifungal prophylaxis at those patients at highest risk of IFD, who stand to benefit most from any antifungal prophylaxis strategy.

OBJECTIVES

To develop and validate risk models to identify non-neutropenic, critically ill adult patients at high risk of invasive Candida infection, who would benefit from antifungal prophylaxis, and to assess the cost-effectiveness of targeting antifungal prophylaxis to high-risk patients based on these models.

DESIGN

Systematic review, prospective data collection, statistical modelling, economic decision modelling and value of information analysis.

SETTING

Ninety-six UK adult general critical care units.

PARTICIPANTS

Consecutive admissions to participating critical care units.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Invasive fungal disease, defined as a blood culture or sample from a normally sterile site showing yeast/mould cells in a microbiological or histopathological report. For statistical and economic modelling, the primary outcome was invasive Candida infection, defined as IFD-positive for Candida species.

RESULTS

Systematic review: Thirteen articles exploring risk factors, risk models or clinical decision rules for IFD in critically ill adult patients were identified. Risk factors reported to be significantly associated with IFD were included in the final data set for the prospective data collection.

DATA COLLECTION

Data were collected on 60,778 admissions between July 2009 and March 2011. Overall, 383 patients (0.6%) were admitted with or developed IFD. The majority of IFD patients (94%) were positive for Candida species. The most common site of infection was blood (55%). The incidence of IFD identified in unit was 4.7 cases per 1000 admissions, and for unit-acquired IFD was 3.2 cases per 1000 admissions. Statistical modelling: Risk models were developed at admission to the critical care unit, 24 hours and the end of calendar day 3. The risk model at admission had fair discrimination (c-index 0.705). Discrimination improved at 24 hours (c-index 0.823) and this was maintained at the end of calendar day 3 (c-index 0.835). There was a drop in model performance in the validation sample. Economic decision model: Irrespective of risk threshold, incremental quality-adjusted life-years of prophylaxis strategies compared with current practice were positive but small compared with the incremental costs. Incremental net benefits of each prophylaxis strategy compared with current practice were all negative. Cost-effectiveness acceptability curves showed that current practice was the strategy most likely to be cost-effective. Across all parameters in the decision model, results indicated that the value of further research for the whole population of interest might be high relative to the research costs.

CONCLUSIONS

The results of the Fungal Infection Risk Evaluation (FIRE) Study, derived from a highly representative sample of adult general critical care units across the UK, indicated a low incidence of IFD among non-neutropenic, critically ill adult patients. IFD was associated with substantially higher mortality, more intensive organ support and longer length of stay. Risk modelling produced simple risk models that provided acceptable discrimination for identifying patients at 'high risk' of invasive Candida infection. Results of the economic model suggested that the current most cost-effective treatment strategy for prophylactic use of systemic antifungal agents among non-neutropenic, critically ill adult patients admitted to NHS adult general critical care units is a strategy of no risk assessment and no antifungal prophylaxis.

FUNDING

Funding for this study was provided by the Health Technology Assessment programme of the National Institute for Health Research.

2-hydroxyisocaproic acid is fungicidal for Candida and Aspergillus species

The amino acid derivative 2-hydroxyisocaproic acid (HICA) is a nutritional additive used to increase muscle mass. Low levels can be detected in human plasma as a result of leucine metabolism. It has broad antibacterial activity but its efficacy against pathogenic fungi is not known. The aim was to test the efficacy of HICA against Candida and Aspergillus species. Efficacy of HICA against 19 clinical and reference isolates representing five Candida and three Aspergillus species with variable azole antifungal sensitivity profiles was tested using a microdilution method. The concentrations were 18, 36 and 72 mg ml(-1) . Growth was determined spectrophotometrically for Candida isolates and by visual inspection for Aspergillus isolates, viability was tested by culture and impact on morphology by microscopy. HICA of 72 mg ml(-1) was fungicidal against all Candida and Aspergillus fumigatus and Aspergillus terreus isolates. Lower concentrations were fungistatic. Aspergillus flavus was not inhibited by HICA. HICA inhibited hyphal formation in susceptible Candida albicans and A. fumigatus isolates and affected cell wall integrity. In conclusion, HICA has broad antifungal activity against Candida and Aspergillus at concentrations relevant for topical therapy. As a fungicidal agent with broad-spectrum bactericidal activity, it may be useful in the topical treatment of multispecies superficial infections.

Outpatient systemic antimycotic and antifungal use in Europe: new outcome measure provides new insight

To broaden our understanding of outpatient systemic antimycotic and antifungal use in Europe, use data in defined daily doses (DDD) were complemented with data in packages and the results were compared. Within the European Surveillance of Antimicrobial Consumption project and using the Anatomical Therapeutic Chemical (ATC) classification, data on outpatient use of all 14 antimycotics (12) and antifungals (2) for systemic use (ATC J02 and D01B), aggregated at the level of the active substance, were collected for 2009. Their use was expressed in DDD per 1000 inhabitants per day (DID) and in packages per 1000 inhabitants per day (PID) (WHO Collaborating Centre for Drug Statistics Methodology ATC/DDD version 2011). In total, 24 countries delivered data in DID; 13 countries also delivered data in PID. In DID, Belgium had the highest (3.24 DID) and Romania the lowest (0.38 DID) total outpatient antimycotic and antifungal use. In PID, Greece had the highest (0.44 PID) and Sweden the lowest (0.08 PID) use. In DID, terbinafine was the most used substance in 19/24 countries (10/13 countries providing DID and PID data). In PID, fluconazole was the most used substance in all 13 countries. Combining DID and PID data substantially improved the interpretation of total outpatient antimycotic and antifungal use in Europe, and both outcome measures should be used for surveillance of these compounds. High use of fluconazole in PID might be more relevant for surveillance of antimicrobial consumption in relation to resistance than high use of terbinafine in DID.

A prospective, cohort, multicentre study of candidaemia in hospitalized adult patients with haematological malignancies

Invasive candidiasis is a life-threatening infection in patients with haematological malignancies. The objective of our study was to determine the incidence, microbiological characteristics and clinical outcome of candidaemia among hospitalized adult patients with haematological malignancies. This is a population-based, prospective, multicentre study of patients ≥ 18 years admitted to haematology and/or haematopoietic stem cell transplantation units of nine tertiary care Greek hospitals from January 2009 through to February 2012. Within this cohort, we conducted a nested case-control study to determine the risk factors for candidaemia. Stepwise logistic regression was used to identify independent predictors of 28-day mortality. Candidaemia was detected in 40 of 27,864 patients with haematological malignancies vs. 967 of 1,158,018 non-haematology patients for an incidence of 1.4 cases/1000 admissions vs. 0.83/1000 respectively (p <0.001). Candidaemia was caused predominantly (35/40, 87.5%) by non-Candida albicans species, particularly Candida parapsilosis (20/40, 50%). In vitro resistance to at least one antifungal agent was observed in 27% of Candida isolates. Twenty-one patients (53%) developed breakthrough candidaemia while receiving antifungal agents. Central venous catheters, hypogammaglobulinaemia and a high APACHE II score were independent risk factors for the development of candidaemia. Crude mortality at day 28 was greater in those with candidaemia than in control cases (18/40 (45%) vs. 9/80 (11%); p <0.0001). In conclusion, despite antifungal prophylaxis, candidaemia is a relatively frequent infection associated with high mortality caused by non-C. albicans spp., especially C. parapsilosis. Central venous catheters and hypogammaglobulinaemia are independent risk factors for candidaemia that provide potential targets for improving the outcome.

Recommendations for the management of candidemia in neonates in Latin America. Latin America Invasive Mycosis Network

Candidemia is one of the most frequent opportunistic mycoses worldwide. Limited epidemiological studies in Latin America indicate that incidence rates are higher in this region than in the Northern Hemisphere. Diagnosis is often made late in the infection, affecting the initiation of antifungal therapy. A more scientific approach, based on specific parameters, for diagnosis and management of candidemia in Latin America is warranted. 'Recommendations for the diagnosis and management of candidemia' are a series of manuscripts that have been developed by members of the Latin America Invasive Mycosis Network. They aim to provide a set of best-evidence recommendations for the diagnosis and management of candidemia. This publication, 'Recommendations for the management of candidemia in neonates in Latin America', was written to provide guidance to healthcare professionals on the management of neonates who have, or who are at risk of, candidemia. Computerized searches of existing literature were performed by PubMed. The data were extensively reviewed and analyzed by members of the group. The group also met on two occasions to pose questions, discuss conflicting views, and deliberate on a series of management recommendations. 'Recommendations for the management of candidemia in neonates in Latin America' includes prophylaxis, empirical therapy, therapy for proven candidemia, patient work-up following diagnosis of candidemia, central venous catheter management, and management of complications. This manuscript is the fourth of this series that deals with diagnosis and treatment of invasive candidiasis. Other publications in this series include: 'Recommendations for the diagnosis of candidemia in Latin America', 'Recommendations for the management of candidemia in adults in Latin America', and 'Recommendations for the management of candidemia in children in Latin America'.

[Recommendations for the management of candidemia in neonates in Latin America. Grupo Proyecto Épico]

Candidemia is one of the most frequent opportunistic mycoses worldwide. Limited epidemiological studies in Latin America indicate that incidence rates are higher in this region than in the Northern Hemisphere. Diagnosis is often made late in the infection, affecting the initiation of antifungal therapy. A more scientific approach, based on specific parameters, for diagnosis and management of candidemia in Latin America is warranted. 'Recommendations for the diagnosis and management of candidemia' are a series of manuscripts that have been developed by members of the Latin America Invasive Mycosis Network. They aim to provide a set of best-evidence recommendations for the diagnosis and management of candidemia. This publication, 'Recommendations for the management of candidemia in neonates in Latin America', was written to provide guidance to healthcare professionals on the management of neonates who have, or who are at risk of, candidemia. Computerized searches of existing literature were performed by PubMed. The data were extensively reviewed and analyzed by members of the group. The group also met on two occasions to pose questions, discuss conflicting views, and deliberate on a series of management recommendations. 'Recommendations for the management of candidemia in neonates in Latin America' includes prophylaxis, empirical therapy, therapy for proven candidemia, patient work-up following diagnosis of candidemia, central venous catheter management, and management of complications. This manuscript is the fourth of this series that deals with diagnosis and treatment of invasive candidiasis. Other publications in this series include: 'Recommendations for the diagnosis of candidemia in Latin America', 'Recommendations for the management of candidemia in adults in Latin America', and 'Recommendations for the management of candidemia in children in Latin America'.

Prophylactic systemic antifungal agents to prevent mortality and morbidity in very low birth weight infants

BACKGROUND

Invasive fungal infection is an important cause of mortality and morbidity in very low birth weight infants. Early diagnosis is difficult and treatment is often delayed. Systemic antifungal agents (usually azoles) are increasingly used as prophylaxis against invasive fungal infection.

OBJECTIVES

To assess the effect of prophylactic systemic antifungal therapy on mortality and morbidity in very low birth weight infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 3), MEDLINE, EMBASE, and CINAHL (to August 2012), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised controlled trials or quasi-randomised controlled trials that compared the effect of prophylactic systemic antifungal therapy versus placebo or no drug or another antifungal agent or dose regimen in very low birth weight infants.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by two review authors.

MAIN RESULTS

We identified 11 eligible trials enrolling a total of 1136 infants. Seven trials (involving 880 infants) compared systemic antifungal prophylaxis versus placebo or no drug. These trials were generally small but of good methodological quality. Meta-analysis found a statistically significant reduction in the incidence of invasive fungal infection in infants who received systemic antifungal prophylaxis (typical risk ratio (RR) 0.41, 95% confidence interval (CI) 0.27 to 0.61; risk difference (RD) -0.09, 95% CI -0.14 to -0.05). The average incidence of invasive fungal infection in the control groups of the trials (16%) was much higher than that generally reported from large cohort studies (< 5%). Meta-analysis did not find a statistically significant difference in the risk of death prior to hospital discharge (typical RR 0.74, 95% CI 0.52 to 1.05; RD -0.04, 95% CI -0.08 to 0.01). Very limited data on long-term neurodevelopmental outcomes were available. Two trials that compared systemic versus oral or topical non-absorbed antifungal prophylaxis did not detect any statistically significant effects on invasive fungal infection or mortality. Two trials that compared different dose regimens of prophylactic intravenous fluconazole did not detect any significant differences in infection rates or mortality.

AUTHORS' CONCLUSIONS

Prophylactic systemic antifungal therapy reduces the incidence of invasive fungal infection in very low birth weight infants. This finding should be interpreted and applied cautiously since the incidence of invasive fungal infection was very high in the control groups of most of the included trials. Meta-analysis does not demonstrate a statistically significant effect on mortality. There are currently only limited data on the long-term neurodevelopmental consequences for infants exposed to this intervention. In addition, there is a need for further data on the effect of the intervention on the emergence of organisms with antifungal resistance.

Prophylactic oral/topical non-absorbed antifungal agents to prevent invasive fungal infection in very low birth weight infants

BACKGROUND

Invasive fungal infection is an important cause of mortality and morbidity in very preterm or very low birth weight infants. Uncertainty exists about the effect of prophylactic oral/topical non-absorbed antifungals to reduce mucocutaneous colonisation and so limit the risk of invasive fungal infection in this population.

OBJECTIVES

To assess the effect of prophylactic oral/topical non-absorbed antifungal therapy on the incidence of invasive fungal infection, mortality and morbidity in very preterm or very low birth weight infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL: The Cochrane Library, 2012, Issue 3), MEDLINE, EMBASE, and CINAHL (to August 2012), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised controlled trials or quasi-randomised controlled trials that compared the effect of prophylactic oral/topical non-absorbed antifungal therapy versus placebo or no drug or another antifungal agent or dose regimen in very preterm or very low birth weight infants.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group with separate evaluation of trial quality and data extraction by two review authors.

MAIN RESULTS

Four trials, in which a total of 1800 infants participated, compared oral/topical non-absorbed antifungal prophylaxis (nystatin or miconazole) with placebo or no drug. These trials had various methodological weaknesses including quasi-randomisation, lack of allocation concealment, and lack of blinding of intervention and outcomes assessment. The incidence of invasive fungal infection was very high in the control groups of three of these trials. Meta-analysis found a statistically significant reduction in the incidence of invasive fungal infection [typical risk ratio 0.20 (95% confidence interval 0.14 to 0.27); risk difference -0.18 (-0.21 to -0.16)] but substantial statistical heterogeneity was present. We did not find a statistically significant effect on mortality [typical risk ratio 0.87 (0.72 to 1.05); risk difference -0.03 (-0.06 to 0.01)]. None of the trials assessed posthospital discharge outcomes.Two trials (N = 265) assessed the effect of oral/topical non-absorbed versus systemic antifungal prophylaxis. Meta-analyses did not find any statistically significant differences in the incidences of invasive fungal infection or all-cause mortality.

AUTHORS' CONCLUSIONS

The finding of a reduction in risk of invasive fungal infection in very low birth weight infants treated with oral/topical non-absorbed antifungal prophylaxis should be interpreted cautiously because of methodological weaknesses in the included trials. Further large randomised controlled trials in current neonatal practice settings are needed to resolve this uncertainty. These trials might compare oral/topical non-absorbed antifungal agents with placebo, with each other, or with systemic antifungal agents and should include an assessment of effect on long-term neurodevelopmental outcomes.

Diagnosis and Management of Cryptococcal Relapse

Despite improvements in the antifungal regimens and the roll out of antiretroviral therapy (ART) in sub-Saharan Africa, mortality due to cryptococcal meningitis remains high. Relapse of an initially successfully treated infection contributes to this mortality and is often a clinical dilemma in differentiating between paradoxical immune reconstitution inflammatory syndrome (IRIS) and culture-positive relapse or treatment failure. Herein, we present a clinical case scenario and review the case definitions, differential diagnosis, and management of relapse with an emphasis on the current diagnostic and management strategies. We also highlight the challenges of resistance testing and management of refractory relapse cases. The risk of relapse is influenced by: 1) the choice of induction therapy, with higher mortality risk with fluconazole monotherapy which can select for resistance; 2) non-adherence to or lack of secondary prophylaxis; 3) failure of linkage-to-care or retention-in-care of HIV ART programs.

Strategies for the prevention of neonatal candidiasis

Invasive fungal infections represent the third-leading cause of late-onset sepsis in very-low-birth-weight infants (VLBWI) and have a high rate of infection-associated mortality. The infants at high risk for fungal sepsis are VLBWI with presence of additional risk factors that contribute to increased colonization and concentration of fungal organisms. Colonization with Candida spp. in neonates is secondary to either maternal vertical transmission or nosocomial acquisition in the nursery. Multiple sites may become colonized and a direct correlation between fungal colonization and subsequent progression to invasive candidemia was determined. Randomized, single and multiple-center, placebo-controlled trials found intravenous fluconazole prophylaxis to be effective in decreasing fungal colonization and sepsis for at-risk preterm infants <1500 g birth weight. The prophylactic use of fluconazole was found to be safe with no significant development of fungal resistance. Fluconazole prophylaxis administered to preterm neonates with birth weight <1000 g and/or 27 weeks' gestation or less has the potential of reducing and potentially eliminating invasive fungal infections and Candida-related mortality.

Characterization of the chromosome 4 genes that affect fluconazole-induced disomy formation in Cryptococcus neoformans

Heteroresistance in Cryptococcus neoformans is an intrinsic adaptive resistance to azoles and the heteroresistant phenotype is associated with disomic chromosomes. Two chromosome 1 (Chr1) genes, ERG11, the fluconazole target, and AFR1, a drug transporter, were reported as major factors in the emergence of Chr1 disomy. In the present study, we show Chr4 to be the second most frequently formed disomy at high concentrations of fluconazole (FLC) and characterize the importance of resident genes contributing to disomy formation. We deleted nine Chr4 genes presumed to have functions in ergosterol biosynthesis, membrane composition/integrity or drug transportation that could influence Chr4 disomy under FLC stress. Of these nine, disruption of three genes homologous to Sey1 (a GTPase), Glo3 and Gcs2 (the ADP-ribosylation factor GTPase activating proteins) significantly reduced the frequency of Chr4 disomy in heteroresistant clones. Furthermore, FLC resistant clones derived from sey1Δglo3Δ did not show disomy of either Chr4 or Chr1 but instead had increased the copy number of the genes proximal to ERG11 locus on Chr1. Since the three genes are critical for the integrity of endoplasmic reticulum (ER) in Saccharomyces cerevisiae, we used Sec61ß-GFP fusion as a marker to study the ER in the mutants. The cytoplasmic ER was found to be elongated in sey1Δ but without any discernable alteration in gcs2Δ and glo3Δ under fluorescence microscopy. The aberrant ER morphology of all three mutant strains, however, was discernable by transmission electron microscopy. A 3D reconstruction using Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) revealed considerably reduced reticulation in the ER of glo3Δ and gcs2Δ strains. In sey1Δ, ER reticulation was barely detectable and cisternae were expanded extensively compared to the wild type strains. These data suggest that the genes required for maintenance of ER integrity are important for the formation of disomic chromosomes in C. neoformans under azole stress.

Therapeutic use of a cationic antimicrobial peptide from the spider Acanthoscurria gomesiana in the control of experimental candidiasis

Background

Antimicrobial peptides are present in animals, plants and microorganisms and play a fundamental role in the innate immune response. Gomesin is a cationic antimicrobial peptide purified from haemocytes of the spider Acanthoscurria gomesiana. It has a broad-spectrum of activity against bacteria, fungi, protozoa and tumour cells. Candida albicans is a commensal yeast that is part of the human microbiota. However, in immunocompromised patients, this fungus may cause skin, mucosal or systemic infections. The typical treatment for this mycosis comprises three major categories of antifungal drugs: polyenes, azoles and echinocandins; however cases of resistance to these drugs are frequently reported. With the emergence of microorganisms that are resistant to conventional antibiotics, the development of alternative treatments for candidiasis is important. In this study, we evaluate the efficacy of gomesin treatment on disseminated and vaginal candidiasis as well as its toxicity and biodistribution.

Results

Treatment with gomesin effectively reduced Candida albicans in the kidneys, spleen, liver and vagina of infected mice. The biodistribution of gomesin labelled with technetium-99 m showed that the peptide is captured in the kidneys, spleen and liver. Enhanced production of TNF-α, IFN-γ and IL-6 was detected in infected mice treated with gomesin, suggesting an immunomodulatory activity. Moreover, immunosuppressed and C. albicans-infected mice showed an increase in survival after treatment with gomesin and fluconazole. Systemic administration of gomesin was also not toxic to the mic

Conclusions

Gomesin proved to be effective against experimental Candida albicans infection. It can be used as an alternative therapy for candidiasis, either alone or in combination with fluconazole. Gomesin's mechanism is not fully understood, but we hypothesise that the peptide acts through the permeabilisation of the yeast membrane leading to death and/or releasing the yeast antigens that trigger the host immune response against infection. Therefore, data presented in this study reinforces the potential of gomesin as a therapeutic antifungal agent in both humans and animals.

Mechanistic aspects of photoinactivation of Candida albicans by exogenous porphyrins

The mechanism of photoinactivation of Candida albicans by 3.5 μM uncharged, cationic or anionic porphyrins under blue light (407-420 nm) was found to be dependent on the uptake of porphyrins into yeast cells, and was also dependent on the presence or absence of proteins in the photosensitization medium. In a very protein-rich medium, a decrease in viability was observed only with the uncharged porphyrin. Photoinactivation by uncharged or cationic porphyrins in a protein-poorer medium resulted in total eradication, whereas no significant decrease was observed with the anionic porphyrin. Phototreatment in PBS resulted in eradication with all three porphyrins. X-ray microanalysis after phototreatment by the uncharged or cationic porphyrins in the protein-poor medium exhibited ion loss, indicating cell-membrane damage. Transmission electron microscopy indicated cellular and chromosomal damage. No ion loss or cell damage was observed in this medium with the anionic porphyrin. The efficiency of photoeradication of C. albicans is dependent on porphyrin uptake, which might lead (upon illumination) to processes that facilitate the formation of reactive oxygen species that damage the cells. Uptake of charged porphyrins is dependent on protein quantity and quality in the photosensitization microenvironment. This fact must be taken into account when using charged photosensitizers.

High-Resolution SNP/CGH Microarrays Reveal the Accumulation of Loss of Heterozygosity in Commonly Used Candida albicans Strains

Phenotypic diversity can arise rapidly through loss of heterozygosity (LOH) or by the acquisition of copy number variations (CNV) spanning whole chromosomes or shorter contiguous chromosome segments. In Candida albicans, a heterozygous diploid yeast pathogen with no known meiotic cycle, homozygosis and aneuploidy alter clinical characteristics, including drug resistance. Here, we developed a high-resolution microarray that simultaneously detects ∼39,000 single nucleotide polymorphism (SNP) alleles and ∼20,000 copy number variation loci across the C. albicans genome. An important feature of the array analysis is a computational pipeline that determines SNP allele ratios based upon chromosome copy number. Using the array and analysis tools, we constructed a haplotype map (hapmap) of strain SC5314 to assign SNP alleles to specific homologs, and we used it to follow the acquisition of loss of heterozygosity (LOH) and copy number changes in a series of derived laboratory strains. This high-resolution SNP/CGH microarray and the associated hapmap facilitated the phasing of alleles in lab strains and revealed detrimental genome changes that arose frequently during molecular manipulations of laboratory strains. Furthermore, it provided a useful tool for rapid, high-resolution, and cost-effective characterization of changes in allele diversity as well as changes in chromosome copy number in new C. albicans isolates.

Fluconazole to prevent systemic fungal infections in infants: reviewing the evidence

IN NEONATOLOGY, EVIDENCE-BASED practice (EBP) relies on well-designed, adequately powered trials to guide practitioners. Several large randomized controlled trials (RCTs) have been conducted to explore the use of fluconazole for fungal prophylaxis in premature infants. Despite the findings of these studies, practice varies among units. In a recent survey of members of the American Academy of Pediatrics (AAP), 34 percent of clinicians indicated that they have used antifungal prophylaxis and only 11 percent of clinicians indicated that a written protocol was in place in their NICU. Intravenous (IV) fluconazole (66 percent), oral nystatin (59 percent), and IV amphotericin (21 percent) were the three most commonly used agents among the respondents.1.

Functional characterization and virulence study of ADE8 and GUA1 genes involved in the de novo purine biosynthesis in Candida albicans

Candida albicans is the principal human fungal pathogen that leads to life-threatening mycoses worldwide. To study its pathobiology, we characterized genes for two enzymes involved in the de novo purine biosynthesis pathway: ADE8 (encoding phosphoribosylglycinamide formyl-transferase) and GUA1 (GMP synthase). Heterozygous and homozygous disruption strains were constructed for both genes. We found that ADE8 and GUA1 are conditionally essential; i.e. can be bypassed in the presence of exogenous adenine and guanine, respectively, and that ADE8 plays an additional role in the C1-folate pool. Furthermore, the heterozygotes of ADE8/ade8 and GUA1/gua1 were hypersensitive to methotrexate (an inhibitor of de novo synthesis of tetrahydrofolate) and 6-azauracil (a known inhibitor of the IMP dehydrogenase involved in GMP biosynthesis), respectively. In a murine model of systemic candidiasis, the virulence of both heterozygous strains was marginally attenuated, while the ade8/ade8 and gua1/gua1 strains were completely avirulent. Our results and those of others indicate that many conditional essential genes involved in different biosynthesis pathways are required for systemic candidiasis, likely due to the host nutritional constraints imposed on the pathogen.

Prophylactic oral/topical non-absorbed antifungal agents to prevent invasive fungal infection in very low birth weight infants

BACKGROUND

Invasive fungal infection is an important cause of mortality and morbidity in very preterm (< 32 weeks gestation) or very low birth weight (VLBW) infants. Clinical uncertainly exists about the effect of prophylactic oral/topical non-absorbed antifungals to reduce mucocutaneous colonisation and so limit the risk of invasive fungal infection in this population.

OBJECTIVES

To assess the effect of prophylactic oral/topical non-absorbed antifungal therapy on the incidence of invasive fungal infection, mortality and morbidity in VLBW infants.

SEARCH STRATEGY

The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of the Cochrane Controlled Trials Register (The Cochrane Library, Issue 2, 2009), MEDLINE (1966 - May 2009), EMBASE (1980 - May 2009), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised controlled trials that compared the effect of prophylactic oral/topical non-absorbed antifungal therapy versus placebo or no drug or another antifungal agent or dose regimen in very preterm or VLBW infants.

DATA COLLECTION AND ANALYSIS

Data were extracted using the standard methods of the Cochrane Neonatal Review Group with separate evaluation of trial quality and data extraction by each review author and synthesis of data using relative risk (RR) and risk difference (RD) and weighted mean difference (WMD).

MAIN RESULTS

Three trials, in which a total of 1625 infants participated, have compared oral/topical non-absorbed antifungal prophylaxis (nystatin or miconazole) with placebo or no drug. These trials had various methodological weaknesses including quasi-randomisation, lack of allocation concealment, and lack of blinding of intervention and outcomes assessment. The incidence of invasive fungal infection was very high in the control groups of two of the included trials. Meta-analysis found a statistically significant reduction in the incidence of invasive fungal infection [typical RR 0.19 (95% confidence interval (CI) 0.14, 0.27); typical RD -0.19 (95% CI -0.22,-0.16)] but substantial statistical heterogeneity was detected. A statistically significant effect on mortality was not found [typical RR 0.88 (95% CI 0.72, 1.06); typical RD -0.02 (95% CI -0.06, 0.01)]. Long-term outcomes were not assessed by any of the trials.One small trial (N = 21) that assessed the effect of oral/topical non-absorbed antifungal prophylaxis (nystatin) compared with systemic antifungal (fluconazole) prophylaxis was underpowered to exclude important clinical effects.

AUTHORS' CONCLUSIONS

The finding of a reduction in risk of invasive fungal infection in infants treated with oral/topical non-absorbed antifungal prophylaxis should be interpreted cautiously because of methodological weaknesses in the included trials. Further large randomised controlled trials in current neonatal practice settings are needed to resolve this uncertainty. These trials might compare oral/topical non-absorbed antifungal agents with placebo, with each other, or with systemic antifungal agents and should include an assessment of effect on long-term neurodevelopmental outcomes.

The resistance to fluconazole in patients with esophageal candidiasis

CONTEXT

Esophageal candidiasis is often observed in patients with risk factors for its development and fluconazole is the therapeutic choice for the treatment of this disease.

OBJECTIVES

To determine its frequency, by performing upper digestive endoscopy; to determine Candida species involved in its pathogenesis and verify their distribution according with the predisposing factors and to determine susceptibility to fluconazole in the samples.

METHODS

From March 2006 to April 2007, all patients submitted to esophagogastroduodenoscopy at the Digestive Endoscopy Unit in the Oswaldo Cruz University Hospital, Recife, PE, Brazil, were eligible for the study. Samples were collected from patients who presented lesions consistent with esophageal candidiasis in order to identify Candida species and verify their susceptibility to fluconazole. The predisposing factors for the occurrence of esophageal candidiasis were described.

RESULTS

Of 2,672 patients referred to upper endoscopy at the Digestive Endoscopy Unit, 40 (1.5%) had endoscopic findings compatible with esophageal candidiasis. The average age was 49.1 years. Twenty one patients (52.5%) were less than 50 years old, of which 82.6% were infected with HIV. Most of them (52.5%) were males and 65.0% were inpatients. Diseases were identified in 90% of the patients and 21 (52.5%) were HIV positive. Concerning endoscopic findings, severe forms of esophagitis were found in 50% of the patients with CD4 count <200. Non-albicans Candida species were isolated in 22.7% of HIV positive and in 45% HIV negative patients. A total of 6 (14.28%) samples were resistant to fluconazole, while 2 (4.76%) samples had dose depending susceptibility to this drug.

CONCLUSIONS

Esophageal candidiasis prevalence was low, although within the results described by other authors. Male and inpatients were the most affected. The species isolated varied according to the characteristics of each group studied. Both, resistance and dose-depending susceptibility to fluconazole were considered high.