Differential association of fluconazole dose and dose/MIC ratio with mortality in patients with Candida albicans and non-albicans bloodstream infection

Antifungal properties of abnormal cannabinoid derivatives: Disruption of biofilm formation and gene expression in Candida species

Abnormal cannabinoids (including comp 3) are a class of synthetic lipid compounds with non-psychoactive properties and regioisomer configurations, but distinct from traditional cannabinoids since they do not interact with the established CB1 and CB2 receptors. Previous research showed the cardioprotective and anti-inflammatory potentials of comp 3 and more recently its antimicrobial effect on methicillin-resistant Staphylococcus aureus (MRSA). Given the escalating challenges posed by Candida infections and the rise of antifungal drug resistance, the exploration of novel therapeutic avenues is crucial. This study aimed to assess the anti-Candida properties of newly synthesized AbnCBD derivatives. AbnCBD derivatives were synthesized by acid catalysis-induced coupling and further derivatized. We evaluated the potential of the AbnCBD derivatives to inhibit the growth stages of various Candida species. By in vitro colorimetric assays and in vivo mice experiments, we have shown that AbnCBD derivatives induce differential inhibition of Candida growth. The AbnCBD derivatives, especially comp 3, comp 10, and comp 9 significantly reduced the growth of C. albicans, including FLC-resistant strains, and of C. tropicalis and C. parapsilosis but not of C auris compared to their controls (FLC and 0.5 % DMSO). Comp 3 also disrupted C. albicans biofilm formation and eradicated mature biofilms. Notably, other derivatives of AbnCBD disrupted the biofilm formation and maturation of C. albicans but did not affect yeast growth. In a murine model of VVC, comp 3 demonstrated significant fungal clearance and reduced C. albicans burden compared to vehicle and FLC controls. These findings highlight the potential of AbnCBDs as promising antifungal agents against Candida infections.

The impact of the fluconazole trailing effect on the persistence of Candida albicans bloodstream infection when treated with fluconazole

OBJECTIVES

The trailing effect of Candida species is a phenomenon characterized by reduced but persistent growth at antifungal concentrations above the MIC. We assessed the impact of trailing growth on the persistence of Candida albicans candidemia in patients receiving fluconazole (FLC) therapy.

METHODS

We retrospectively investigated candidemia isolates at three hospitals in southern Taiwan between 2013 and 2020. Patients treated with FLC for FLC-susceptible C. albicans candidemia were enrolled. The degree of trailing was determined as the average growth above the MIC divided by the measured growth at the lowest drug concentration using the EUCAST method and classified into four categories: residual (0.1-5%), slight (6-10%), moderate (11-15%), and heavy trailers (>15%).

RESULTS

Among isolates from 190 patients, the proportions of heavy trailers at 24 hours, 48 hours, and 72 hours were 63.7% (121/190), 63.2% (120/190), and 74.7% (142/190), respectively. Persistent candidemia was observed in 17 (8.9 %) patients. The proportion of persistent C. albicans candidemia in heavy trailing isolates at 48 hours was higher than in isolates without heavy trailing (13.3% [16/120] vs. 1.4% [1/70], p = 0.007). A multivariate analysis showed that immunosuppression (OR = 7.92; 95% CI: 2.38-26.39, p = 0.001), hospitalization days after the index date of C. albicans identification (OR = 1.03; 95% CI: 1.01-1.05, p = 0.011), and heavy trailing isolates at 48 hours (OR = 10.04; 95% CI: 1.27-79.88, p = 0.029) were independent factors for persistent candidemia.

DISCUSSION

The current study revealed that heavy trailing in C. albicans isolates is associated with persistent candidemia in patients receiving FLC treatment.

Antifungal Susceptibility Testing: A Primer for Clinicians

Clinicians treating patients with fungal infections may turn to susceptibility testing to obtain information regarding the activity of different antifungals against a specific fungus that has been cultured. These results may then be used to make decisions regarding a patient's therapy. However, for many fungal species that are capable of causing invasive infections, clinical breakpoints have not been established. Thus, interpretations of susceptible or resistant cannot be provided by clinical laboratories, and this is especially true for many molds capable of causing severe mycoses. The purpose of this review is to provide an overview of susceptibility testing for clinicians, including the methods used to perform these assays, their limitations, how clinical breakpoints are established, and how the results may be put into context in the absence of interpretive criteria. Examples of when susceptibility testing is not warranted are also provided.

Current fluconazole treatment regimens result in under-dosing of critically ill adults during early therapy

PURPOSE

To evaluate current fluconazole treatment regimens in critically ill adults over the typical treatment course.

METHODS

Data from critically ill adults treated with fluconazole (n=30) were used to develop a population pharmacokinetic model. Probability of target attainment (PTA) (fAUC₂₄/MIC >100) was determined from simulations for four previously proposed treatment regimens: (i) 400 mg once daily, (ii) an 800 mg loading dose followed by 400 mg once daily, (iii) 400 mg twice daily, and (iv) a 12 mg/kg loading dose followed by 6 mg/kg once daily. The effect of body weight (40, 70, 120 kg) and renal function (continuous renal replacement therapy (CRRT); 20, 60, 120, 180 mL/min creatinine clearance) on PTA was assessed.

RESULTS

Early (0-48 h) fluconazole target attainment for infections with a minimum inhibitory concentration (MIC) of 2 mg/L was highly variable. PTA was highest with an 800 mg loading dose for underweight (40 kg) patients and with a 12 mg/kg loading dose for the remainder. End-of-treatment PTA was highest with the 400 mg twice daily maintenance dosing for patients who were under- or normal weight and 6 mg/kg maintenance dosing for overweight (120 kg) patients. None of the fluconazole regimens reliably attained early targets for MICs of ≥4 mg/L.

CONCLUSION

Current fluconazole dosing regimens do not achieve adequate early target attainment in critically ill adults, particularly in those who are overweight, have higher creatinine clearance, or are undergoing CRRT. Current fluconazole dosing strategies are generally inadequate to treat organisms with an MIC of ≥4 mg/L.

Role and Interpretation of Antifungal Susceptibility Testing for the Management of Invasive Fungal Infections

Invasive fungal infections (IFIs) are associated with high mortality rates and timely appropriate antifungal therapy is essential for good outcomes. Emerging antifungal resistance among Candida and Aspergillus spp., the major causes of IFI, is concerning and has led to the increasing incorporation of in vitro antifungal susceptibility testing (AST) to guide clinical decisions. However, the interpretation of AST results and their contribution to management of IFIs remains a matter of debate. Specifically, the utility of AST is limited by the delay in obtaining results and the lack of pharmacodynamic correlation between minimal inhibitory concentration (MIC) values and clinical outcome, particularly for molds. Clinical breakpoints for Candida spp. have been substantially revised over time and appear to be reliable for the detection of azole and echinocandin resistance and for outcome prediction, especially for non-neutropenic patients with candidemia. However, data are lacking for neutropenic patients with invasive candidiasis and some non-albicans Candida spp. (notably emerging Candida auris). For Aspergillus spp., AST is not routinely performed, but may be indicated according to the epidemiological context in the setting of emerging azole resistance among A. fumigatus. For non-Aspergillus molds (e.g., Mucorales, Fusarium or Scedosporium spp.), AST is not routinely recommended as interpretive criteria are lacking and many confounders, mainly host factors, seem to play a predominant role in responses to antifungal therapy. This review provides an overview of the pre-clinical and clinical pharmacodynamic data, which constitute the rationale for the use and interpretation of AST testing of yeasts and molds in clinical practice.

Multilocus Sequence Typing Reveals Clonality of Fluconazole-Nonsusceptible Candida tropicalis: A Study From Wuhan to the Global

Candida tropicalis is a globally distributed human pathogenic yeast, and its increasing resistance to azoles makes clinical treatment difficult. In this study, we investigated the clinical features, azole resistance and genetic relatedness of 87 C. tropicalis isolates from central China and combined with the global database to explore the relationship between genetic information and fluconazole susceptibility. Of the 55 diploid sequence types (DSTs) identified by multilocus sequence typing (MLST), 27 DSTs were new to the C. tropicalis MLST database. Fluconazole-nonsusceptible (FNS) isolates were genetically closely related. goeBURST analysis showed that DST225, DST376, DST506, and DST546 formed a distinct and unique FNS clonal complex (CC) in Wuhan. The local FNS CC belongs to the large FNS CC (CC2) in China, in which the putative founder DST225 has been reported from the environment. The three most prevalent types (DST506, DST525, and DST546) in Wuhan had high minimum inhibitory concentrations (MICs) for antifungal azoles, and the six possible nosocomial transmissions we captured were all FNS strains, most of which were from CC2. Unique FNS CCs have been found in Singapore (CC8) and India (CC17) and are close to China's CC2 in the minimum spanning tree. There were no FNS CCs outside Asia. This study is the first to reveal a significant correlation between genetic information and fluconazole susceptibility worldwide and to trace geographical locations, which is of great value for molecular epidemiological surveillance and azole-resistance study of C. tropicalis globally.

Antifungal susceptibility testing in Candida, Aspergillus and Cryptococcus infections: are the MICs useful for clinicians?

BACKGROUND

Invasive fungal infections (IFIs) represent a global issue and affect various patient populations. In recent years, resistant fungal isolates showing increased azole or echinocandin MICs have been reported, and their potential clinical impact has been investigated.

AIMS

To provide an update on the epidemiology of resistance among fungi (e.g., Candida spp., Aspergillus spp., and Cryptococcus spp.) and to offer a critical appraisal of the relevant literature regarding the impact of MICs on clinical outcome in patients with IFI.

SOURCES

PubMed search with relevant keywords along with a personal collection of relevant publications.

CONTENT

Although antifungal resistance has been associated with a poorer response to antifungal therapy in various studies, other factors such as comorbidities, septic shock and source of infection appear to be key determinants affecting the clinical outcome of patients with IFI.

IMPLICATIONS

Future international collaborative studies are required to tease out the relative contribution of in vitro antifungal resistance on patient outcomes, thus enabling the optimization of IFI management.

Clonality of Fluconazole-Nonsusceptible Candida tropicalis in Bloodstream Infections, Taiwan, 2011-2017

Candida tropicalis is the leading cause of non-C. albicans candidemia in tropical Asia and Latin America. We evaluated isolates from 344 patients with an initial episode of C. tropicalis candidemia. We found that 58 (16.9%) patients were infected by fluconazole-nonsusceptible (FNS) C. tropicalis with cross resistance to itraconazole, voriconazole, and posaconazole; 55.2% (32/58) of patients were azole-naive. Multilocus sequence typing analysis revealed FNS isolates were genetically closely related, but we did not see time- or place-clustering. Among the diploid sequence types (DSTs), we noted DST225, which has been reported from fruit in Taiwan and hospitals in Beijing, China, as well as DST376 and DST505-7, which also were reported from hospitals in Shanghai, China. Our findings suggest cross-boundary expansion of FNS C. tropicalis and highlight the importance of active surveillance of clinical isolates to detect dissemination of this pathogen and explore potential sources in the community.

Support for fungal infection treatment mediated by pharmacist-led antifungal stewardship activities

OBJECTIVE

At the Yokohama General Hospital, pharmacist-led antimicrobial stewardship programs (ASP) including antifungal stewardship programs (AFP) were started in 2012. To investigate the efficacy of the programs, we compared several parameters that are recommended for the measurement of ASP in Japan based on pre- and post-AFP activities.

PATIENTS AND METHODS

The subjects were inpatients who developed candidemia between April 2008 and March 2016. They were divided into two groups: pre-AFP (April 2008 until March 2012) and post-AFP (April 2012 until March 2016). The results were compared between the two groups.

RESULTS

The cumulative optimal antifungal drug usage rate, as a process parameter, significantly increased in the post-AFP group (p = 0.025). Furthermore, the days of therapy of antifungal drugs in the pre- and post-AFP groups was median 6.0 (interquartile range [IQR] 0.3-15.7) and median 3.4 (IQR 1.9-3.4) per 1,000 patient-days, respectively; there was a significant decrease in the post-AFP group (p < 0.001). Expenditure on antifungal drugs, as an outcome parameter, in the pre- and post-AFP groups was 9390.5 ± 5687.1 and 5930.8 ± 4687.0 US dollars, respectively; there was a significant decrease in the post-AFP group (p = 0.002).

CONCLUSIONS

These results suggest that pharmacist-led antifungal stewardship activities improve both outcome and process parameters.

The association between fluconazole dose and MIC with mortality and persistence in candidemia

To evaluate the association between fluconazole exposure parameters and clinical outcomes in patients with candidemia. We retrospectively included all adults with candidemia in a single center from January 2009 to December 2017, treated initially with fluconazole for fluconazole-susceptible candidemia. We assessed the association between fluconazole exposure parameters and 30-day mortality or 14-day clinical failure, a composite of mortality at day 14 or persistent candidemia ≥ 72 h, in all patients and in patients with C. glabrata candidemia. During the study period, 158 patients fulfilled the inclusion criteria. Main species were C. albicans 66 (41.8%), C. glabrata 35 (22.2%), and C. parapsilosis 31 (19.6%). Sixty patients (38%) died within 30 days. Sixty-one patients (38.6%) experienced 14-day failure. In 30-day survivors, the median AUC₂₄/MIC was 2279 [398, 5989] versus 1764 [238, 6714] h in non-survivors, p = 0.75. Median fluconazole MIC was 0.75 [0.25, 4] and 1 [0.22, 5.50] mg/L, p = 0.54, respectively. Similar non-significant differences were found for other fluconazole exposure parameters and in the 14-day clinical failure analysis. For C. glabrata, a higher AUC₂₄/MIC was observed among 30-day survivors with a median of 230 [77, 539] compared to 96 [75, 164] h in non-survivors, p = 0.008, in parallel with a trend for lower MIC values (median 7 [1, 2] versus 16 [8, 24] mg/L, p = 0.06, respectively). Currently used fluconazole dosing has no association with clinical outcome in Candida with low MIC values. For Candida species with high MICs, attention to dosing is needed.

Factors and outcomes associated with candidemia caused by non-albicans Candida spp versus Candida albicans in children

BACKGROUND

Candidemia in children caused by non-albicans Candida (NAC) spp is increasing in prevalence, but the relevant information is limited.

METHODS

All isolates of pediatric candidemia from a medical center in Taiwan between 2003 and 2015 were enrolled. The characteristics of patients with NAC and Candida albicans candidemia (CAC) were compared.

RESULTS

Among the 319 episodes of candidemia occurring in 262 patients, C albicans accounted for 46.4%. The NAC and CAC groups had no significant differences in demographics, underlying diseases, most risk factors, and clinical characteristics. Patients in the NAC group were significantly more likely to have fluconazole exposure (14.0% vs 6.8%, respectively; P = .045), and NAC species accounted for 70.2% of all recurrent episodes. NAC candidemia had a longer duration of candidemia (median, 3.0 vs 1.0 days after effective antifungal treatment, respectively; P = .001), slower responses to antifungal treatment, and a higher rate of treatment failure than CAC. However, the 2 groups had similar 30-day candidemia-attributable mortality rates. After multivariate logistic regression, longer duration of central venous catheter was the independent risk factor for NAC candidemia in children (odds ratio, 1.21; 95% confidence interval, 1.08-1.35 for every 10-day increment).

CONCLUSIONS

NAC species collectively have emerged as the predominant pathogens of candidemia in children. Prolonged use of a central venous catheter is associated with an increased risk of candidemia caused by NAC species.

Are In Vitro Susceptibilities to Azole Antifungals Predictive of Clinical Outcome in the Treatment of Candidemia?

The purpose of this review is to critically analyze published data evaluating the impact of azole pharmacokinetic and pharmacodynamic parameters, MICs, and Candida species on clinical outcomes in patients with candidemia. Clinical breakpoints (CBPs) for fluconazole and voriconazole, which are used to determine susceptibility, have been defined by the Clinical and Laboratory Standards Institute (CLSI) for Candida species. Studies evaluating the relationship between treatment efficacy and in vitro susceptibility, as well as the pharmacodynamic targets, have been conducted in patients treated with fluconazole for candidemia; however, for species other than Candida albicans and Candida glabrata, and for other forms of invasive candidiasis, data remain limited and randomized trials are not available. Limited data evaluating these relationships with voriconazole are available. While pharmacodynamic targets for posaconazole and isavuconazole have been proposed based upon studies conducted in murine models, CBPs have not been established by CLSI. Fluconazole remains an important antifungal agent for the treatment of candidemia, and data supporting its use based on in vitro susceptibility are growing, particularly for C. albicans and C. glabrata Further investigation is needed to establish the roles of voriconazole, posaconazole, and isavuconazole in the treatment of candidemia and for all agents in the treatment of other forms of invasive candidiasis.

Candidemia due to uncommon Candida species in children: new threat and impacts on outcomes

Many uncommon Candida spp. (species other than C. albicans, C. parapsilosis, C. glabrata, C. tropicalis, and C. krusei) have been shown to emerge in tertiary care facilities. We aimed to investigate these uncommon candidemia in children. Forty-six cases of candidemia caused by uncommon Candida spp. were identified during 2003–2015 from a medical center in Taiwan. The most common specie was C. guilliermondii (31.2%), followed by C. lusitaniae (18.8%) and C. metapsilosis (18.8%). These cases were analyzed and compared with 148 episodes of C. albicans candidemia. The incidence density of uncommon Candida spp. candidemia and the proportion to all candidemia episodes increased substantively during the study period. Prior exposure to azoles was uncommon in the 30 days prior to infection, but fluconazole resistant strains were significantly more common (n = 19, 41.3%). The increased incidence density of uncommon Candida spp. candidemia was associated with increasing use of antifungal agents. No differences in demographics, underlying comorbidities, risk factors, clinical features, dissemination, and 30-day mortality were found between uncommon Candida spp. and C. albicans candidemia. Patients with uncommon Candida spp. candidemia were more likely to require modifications in antifungal treatment and receive echinocandin drugs (43.5% vs 21.6%, p = 0.007). Candidemia caused by uncommon Candida spp. had poorer response to antifungal treatment, led to longer duration of candidemia (median 4.0 versus 2.5 days, p = 0.008), and had a higher treatment failure rate (56.5% vs 38.5%, p = 0.040).

The Impact of Biofilm Formation on the Persistence of Candidemia

This study aimed to determine the predictors of persistent candidemia and examine the impact of biofilm formation by Candida isolates in adult patients with candidemia. Of the adult patients with candidemia in Kaohsiung Chang Gung Memorial Hospital between January 2007 and December 2012, 68 case patients with persistent candidemia (repeated candidemia after a 3-day systemic antifungal therapy) and 68 control patients with non-persistent candidemia (Candida clearance from the bloodstream after a 3-day systemic antifungal therapy) were included based on propensity score matching and matching for the Candida species isolated. Biofilm formation by the Candida species was assessed in vitro using standard biomass assays. Presence of central venous catheters (CVCs) at diagnosis (adjusted odd ratio [AOR], 3.77; 95% confidence interval [CI], 1.09–13.00, p = 0.04), infection with higher biofilm forming strains of Candida species (AOR, 8.03; 95% CI, 2.50–25.81; p < 0.01), and receipt of suboptimal fluconazole doses as initial therapy (AOR, 5.54; 95% CI, 1.53–20.10; p < 0.01) were independently associated with persistent candidemia. Biofilm formation by Candida albicans, C. tropicalis, and C. glabrata strains was significantly higher in the case patients than in the controls. There were no significant differences in the overall mortality and duration of hospitalization between the two groups. Our data suggest that, other than presence of retained CVCs and use of suboptimal doses of fluconazole, biofilm formation was highly associated with development of persistent candidemia.

Survival in Patients with Candida glabrata Bloodstream Infection Is Associated with Fluconazole Dose

Robust pharmacodynamic indices that align fluconazole dose or exposure with outcomes in invasive candidiasis due to Candida glabrata remain elusive. The purpose of this retrospective multicenter study was to evaluate a cohort of 127 patients with C. glabrata fungemia treated with fluconazole, using adjusted analyses to identify risk factors for 28-day death. No significant correlations were found between fluconazole area under the curve (AUC), AUC/MIC ratio, or MIC and survival. In multivariate logistic regression analyses, however, higher average fluconazole dose (odds ratio [OR], 1.006 [95% confidence interval [CI], 1.001 to 1.010]; P = 0.008), average fluconazole dose of ≥400 mg (OR, 3.965 [95% CI, 1.509 to 10.418]; P = 0.005), and higher fluconazole dose on day 1 of therapy (OR, 1.007 [95% CI, 1.002 to 1.011]; P = 0.002) were found to be independent predictors of 28-day survival. Additionally, the presence of a central venous catheter at the time of infection was found to be a significant risk factor for death. In conclusion, we found fluconazole dose to be an independent predictor of 28-day survival for patients with C. glabrata fungemia, with doses of ≥400 mg/day being associated with 28-day survival rates approaching 90%. These data indicate the use and efficacy of fluconazole in the treatment of this serious infection. Aggressive dosing appears to be necessary when fluconazole is used for the treatment of C. glabrata fungemia, irrespective of MIC.

Development of a phosphorylated Momordica charantia protein system for inhibiting susceptible dose-dependent C. albicans to available antimycotics: An allosteric regulation of protein

A regulatory Momordica charantia protein system was constructed allosterically by in vitro protein phosphorylation, in an attempt to evaluate antimycological pluripotency against dose-dependent susceptibilities in C. albicans. Fungal strain lineages susceptible to ketoconazole, econazole, miconazole, 5-flucytosine, nystatin and amphotericin B were prepared in laboratory, followed by identification via antifungal susceptibility testing. Protein phosphorylation was carried out in reactions with 5'-adenylic, guanidylic, cytidylic and uridylic acids and cyclic adenosine triphosphate, through catalysis of cyclin-dependent kinase 1, protein kinase A and protein kinase C respectively. Biochemical analysis of enzymatic reactions indicated the apparent Michaelis-Menten constants and maximal velocity values of 16.57-91.97mM and 55.56-208.33μM·min^-1, together with an approximate 1:1 reactant stoichiometric ratio. Three major protein phosphorylation sites were theoretically predicted at Thr255, Thr102 and Thr24 by a KinasePhos tool. Additionally, circular dichroism spectroscopy demonstrated that upon phosphorylation, protein folding structures were decreased in random coil, β6-sheet and α1-helix partial regions. McFarland equivalence standard testing yielded the concentration-dependent inhibition patterns, while fungus was grown in Sabouraud's dextrose agar. The minimal inhibitory concentrations of 0.16-0.51μM (at 50% response) were obtained for free protein and phosphorylated counterparts. With respect to the 3-cycling susceptibility testing regimen, individuals of total protein forms were administrated in-turn at 0.14μM/cycle. Relative inhibition ratios were retained to 66.13-81.04% of initial ones regarding the ketoconazole-susceptible C. albicans growth. An inhibitory protein system, with an advantage of decreasing antifungal susceptibilities to diverse antimycotics, was proposed because of regulatory pluripotency whereas little contribution to susceptibility in itself.

Impact of fluconazole susceptibility on the outcome of patients with candidaemia: data from a population-based surveillance

OBJECTIVES

The clinical correlation of fluconazole antifungal susceptibility testing (AST) for Candida isolates and its integration with pharmacokinetics/pharmacodynamics (PK/PD) parameters is unclear. We analysed the impact of fluconazole minimum inhibitory concentration (MIC) values, 24-hour area under the concentration-time curve (AUC₂₄) and AUC₂₄/MIC ratio on the outcome of candidemic patients.

METHODS

We included 257 episodes of candidaemia treated with fluconazole monotherapy for ≥72 hours from a population-based surveillance conducted in 29 hospitals (CANDIPOP Project). AST was centrally performed by European Committee on Antimicrobial Susceptibility Testing (EUCAST) and Clinical and Laboratory Standards Institute (CLSI) microdilution methods. Primary outcome was clinical failure (30-day mortality and/or persistent candidaemia for ≥72 hours from initiation of therapy). Secondary outcomes included early (3-7 days) and late (3-30 days) mortality.

RESULTS

Rates of clinical failure, early and late mortality among evaluable episodes were 32.3% (80/248), 3.1% (8/257) and 23.4% (59/248). There was no relationship between fluconazole MIC values or PK/PD parameters and clinical failure. Although MIC values ≥2 mg/L by EUCAST (positive predictive value 32.1%, negative predictive value 68.7%) and ≥0.5 mg/L by CLSI (positive predictive value 34.8%, negative predictive value 74.4%) appeared to be optimal for predicting clinical failure, no significant associations remained after multivariate adjustment (odds ratio 1.67; 95% confidence interval 0.48-5.79; p 0.423). Lack of association was consistent for alternative thresholds (including proposed clinical breakpoints). The only association found for secondary outcomes was between an AUC₂₄/MIC ratio >400 h by CLSI and early mortality (odds ratio 0.18; 95% confidence interval 0.04-0.98; p 0.026).

CONCLUSIONS

High fluconazole MIC values did not negatively impact outcome of patients with candidaemia treated with fluconazole. No effect of PK/PD targets on the risk of clinical failure was found.

Diagnosis and management of invasive candidiasis in the ICU: an updated approach to an old enemy

Invasive fungal infections, particularly those caused by Candida species, are not uncommon in critically ill patients and are associated with considerable morbidity and mortality. Diagnosis and management of these infections can be challenging. In this review, we will briefly discuss recent epidemiological data on invasive candidiasis and current diagnostic approaches before concentrating on antifungal treatments.

Adding Biotin to Parenteral Nutrition Solutions Without Lipid Accelerates the Growth of Candida albicans

BACKGROUND

We have previously demonstrated that Candida albicans requires multivitamins (MVs) or lipid to increase rapidly in parenteral nutrition (PN) solutions. In this study, in detail, the effects of vitamins on the growth of C. albicans in PN solutions without lipid were investigated.

METHODS

In the 1st experiment, a commercial PN solution without lipid was supplemented with water-soluble vitamins (SVs: vitamins B1, B2, B6, B12 and C, folic acid, nicotinamide, biotin and panthenol), water-insoluble vitamins (IVs: vitamins A, D, E and K) or both (MVs). In the 2nd experiment, the test solutions were prepared by supplementing the PN solution with one of each or all of the SVs. In the 3rd experiment, another commercial peripheral PN (PPN) solution without lipid was supplemented with SVs, nicotinic acid, biotin or both nicotinic acid and biotin. In each of the experiments, a specified number of C. albicans organisms was added to each test solution, and all of the test solutions were allowed to stand at room temperature (23-26ºC). The number of C. albicans was counted at 0, 24, 48 and 72 hours after the addition of the organism.

RESULTS

In the 1st experiment, the C. albicans increased rapidly in the PN solution supplemented with the SVs, but increased slowly without the SVs, regardless of the addition of the IVs. In the 2nd experiment, the C. albicans increased rapidly in the PN solution supplemented with the SVs or biotin, but increased slowly with each of the other water-soluble vitamins. In the 3rd experiment, the C. albicans increased rapidly in the PPN solution supplemented with the SVs or biotin, but increased slowly with the addition of nicotinic acid.

CONCLUSIONS

These results suggested that adding MVs or SVs to PN solutions without lipid promotes the growth of C. albicans, and that this effect is mostly attributable to biotin.

Defining the frontiers between antifungal resistance, tolerance and the concept of persistence

A restricted number of antifungal agents are available for the therapy of fungal diseases. With the introduction of epidemiological cut-off values for each agent in important fungal pathogens based on the distribution of minimal inhibitory concentration (MIC), the distinction between wild type and drug-resistant populations has been facilitated. Antifungal resistance has been described for all currently available antifungal agents in several pathogens and most of the associated resistance mechanisms have been deciphered at the molecular level. Clinical breakpoints for some agents have been proposed and can have predictive value for the success or failure of therapy. Tolerance to antifungals has been a much more ignored area. By definition, tolerance operates at antifungal concentrations above individual intrinsic inhibitory values. Important is that tolerance to antifungal agents favours the emergence of persister cells, which are able to survive antifungal therapy and can cause relapses. Here we will review the current knowledge on antifungal tolerance, its potential mechanisms and also evaluate the role of antifungal tolerance in the efficacy of drug treatments.