Comparison of Antifungal Azole Interactions with Adult Cytochrome P450 3A4 versus Neonatal Cytochrome P450 3A7

Adult drug metabolism is dominated by cytochrome P450 3A4 (CYP3A4), which is often inhibited by antifungal azole drugs, resulting in potential alterations in drug metabolism and adverse drug/drug interactions. In the fetal and neonatal stages of life, the 87% identical cytochrome P450 3A7 (CYP3A7) is expressed but not CYP3A4. Azole antifungals developed for adults are also used in neonates, assuming they interact similarly with both enzymes, but systematic information is lacking. Herein a method was developed for generating recombinant purified CYP3A7. Thirteen different azoles were then evaluated for binding and inhibition of purified human CYP3A4 versus CYP3A7. All imidazole-containing azoles bound both enzymes via coordination to the heme iron and inhibited both with IC50 values ranging from 180 nM for clotrimazole to the millimolar range for imidazole itself. Across this wide range of potencies, CYP3A4 was consistently inhibited more strongly than CYP3A7, with clotrimazole being the least selective (1.5-fold) inhibitor and econazole the most selective (12-fold). Observations for 1,2,4-triazole-containing azoles were more varied. Most bound to CYP3A4 via coordination to the heme iron, but several also demonstrated evidence of a distinct binding mode at low concentrations. However, only posaconazole inhibited CYP3A4. Of the triazoles, only posaconazole inhibited CYP3A7, again less potently than CYP3A4. Spectral evidence for binding was weak or nonexistent for all triazoles. Overall, although the details of binding interactions do vary, the same azole compounds inhibit both enzymes, albeit with weaker interactions with CYP3A7 compared with CYP3A4.

Management of Invasive Fungal Infections in Pediatric Acute Leukemia and the Appropriate Time for Restarting Chemotherapy

OBJECTIVE

Rapid and effective treatment of invasive fungal infection (IFI) in patients with leukemia is important for survival. In this study, we aimed to describe variations regarding clinical features, treatment modalities, time of restarting chemotherapy, and outcome in children with IFI and acute leukemia (AL).

MATERIALS AND METHODS

The charts of all pediatric AL patients in our clinic between the years of 2001 and 2013 were retrospectively reviewed. All patients received prophylactic fluconazole during the chemotherapy period.

RESULTS

IFI was identified in 25 (14%) of 174 AL patients. Most of them were in the consolidation phase of chemotherapy and the patients had severe neutropenia. The median time between leukemia diagnosis and definition of IFI was 122 days. Twenty-four patients had pulmonary IFI. The most frequent finding on computed tomography was typical parenchymal nodules. The episodes were defined as proven in 4 (16%) patients, probable in 7 (28%) patients, and possible in 14 (56%) patients. The median time for discontinuation of chemotherapy was 27 days. IFI was treated successfully in all patients with voriconazole, amphotericin B, caspofungin, or posaconazole alone or in combination. Chemotherapy was restarted in 50% of the patients safely within 4 weeks and none of those patients experienced reactivation of IFI. All of them were given secondary prophylaxis. The median time for antifungal treatment and for secondary prophylaxis was 26 and 90 days, respectively. None of the patients died due to IFI.

CONCLUSION

Our data show that rapid and effective antifungal therapy with rational treatment modalities may decrease the incidence of death and that restarting chemotherapy within several weeks may be safe in children with AL and IFI.

[Adequacy of antifungal agents in a teaching hospital: too many inappropriate prescriptions despite training]

OBJECTIVES

The aim of this study was to assess adequacy and conformity of systemic antifungal drugs prescriptions in comparison with local, French, European and international recent guidelines in the Grenoble Teaching Hospital.

METHODS

Each prescription of itraconazole, liposomal amphotericin B, voriconazole, caspofungin, micafungin, posaconazole and anidulafungin made between February and October 2010 were reviewed by an infectious diseases specialist. Fluconazole prescriptions' were reviewed only for 15 days.

RESULTS

Two hundred and eight patients received 295 systemic antifungal prescriptions. Most of them had at least one risk factor and immunodeficiency was one of the most common. Antifungal treatment starting, molecules choice, administrations conformity (dosage, administration way) were appropriate in 126 cases on 208 (60.5 %) at the treatment beginning evaluation and in 171 cases on 295 (58 %) at the treatment ending evaluation. Antifungal combinations (9.4 %) were less frequent than in the study carried out in Grenoble teaching hospital in 2007 (16.3 %). Most common non-conformities encountered were use of caspofungin instead of fluconazole, antifungal combinations prescription, administration modalities misguiding. The economy that could have been generated by appropriate prescriptions represented 18 % of the antifungal budget of 2010 in the Grenoble Teaching Hospital.

CONCLUSION

An improvement was highlighted in the antifungal prescriptions in comparison to the previous study led in 2007 in the Universitary Grenoble Hospital. However, the antifungal use was not optimal and further training is planned.

A randomized, double-blind, prospective study of caspofungin vs. amphotericin B for the treatment of invasive candidiasis in newborn infants

BACKGROUND

Caspofungin is an echinocandin agent with fungicidal activity against Candida species.

OBJECTIVE

To assess the efficacy, safety and tolerability of caspofungin relative to amphotericin B in neonates with invasive candidiasis.

PATIENTS AND METHODS

Thirty-two neonates with invasive candidiasis were randomly assigned to receive either caspofungin (n = 15) or amphotericin B (n = 17). Efficacy was evaluated, with a successful outcome defined as fulfilling all the components of a prespecified five-part composite endpoint. Evaluation of safety was done by monitoring drug-related adverse events.

RESULTS

At the end of intravenous therapy, evaluation showed that caspofungin was superior, with a favorable response in 86.7% of patients as compared with 41.7% of those who received amphotericin B (p = 0.04). There were significantly fewer adverse events in the caspofungin group than in the amphotericin B group.

CONCLUSION

Caspofungin is more effective, safer and alternative to amphotericin B for the treatment of invasive candidiasis in newborn infants.

Epidemiology of visceral mycoses in autopsy cases in Japan: comparison of the data from 1989, 1993, 1997, 2001, 2005 and 2007 in Annual of Pathological Autopsy Cases in Japan

The data on visceral mycoses reported in the " Annual of Pathological Autopsy Cases in Japan " were analyzed epidemiologically every four years from 1989 to 2005, and in 2007. The frequency rates of visceral mycoses dropped sharply between 1989 (4.5%) and 1994 (3.2%), but by 2001 had risen again and have remained (4.4-4.6%) generally stable since then. The predominant causative agents were Candida and Aspergillus. Although the rate of candidosis showed a gradual decrease, the rate of aspergillosis showed an increase by degrees. Furthermore, the rate of aspergillosis exceeded that of candidosis in 1994, and the difference in the rates between the two conditions apparently further increased until 2001. After 2005, however no changes in this difference were observed. For complicated infections, the incidence of coinfection with Aspergillus and Candida showed a decreasing, and that with Aspergillus and Zygomycetes showed an increasing tendency. Severe infections with Zygomycetes showed a clear increase from 57.4% in 1989 to 88.9% in 2007. Comparing underlying diseases with mycoses in 1989 and 2007, leukemia (including myelodysplastic syndrome) decreased from 26.1% to 18.8% and bacterial infections (including interstitial pneumonia) increased from 11.1% to 22.1%. By age, the highest frequency rate of mycoses was observed in the range of 60-79 years, and the frequency rate of exogenous fungal infections such as aspergillosis, cryptococcosis, zygomycosis and trichosporonosis showed an increasing trend in the less than one-year old group.

Anidulafungin: is it a promising option in the treatment of pediatric invasive fungal infections?

Cases of invasive fungal infections are increasing globally due to an increase in the immunosuppressed population, the use of broad-spectrum antibiotics and the invasive instrumentation of patients in intensive care units. Ongoing emergence of resistance and problems with toxicity have resulted in the need for the development of new antifungal agents. Anidulafungin, the most recently developed echinocandin, is approved by the US FDA for treatment of candidemia, other forms of Candida infection and esophageal candidiasis in non-neutropenic adult patients, but it is not currently licensed for pediatric usage. The drug is projected to be distinctive owing to its unique pharmacokinetics and is already listed in adult antifungal treatment guidelines. In this article, anidulafungin will be reviewed with a focus on pediatric patients.

Invasive Candida infections in solid organ transplant recipient children

Solid organ transplantation (SOT) is now an accepted therapy for many end-stage organ disorders and fungal infections are the principal cause of infection-related mortality in SOT recipients. Among invasive fungal infections, Candida species are the most common pathogens identified, associated with high mortality rates. The epidemiology and clinical manifestations of Candida infections vary with the type of organ transplantation. This article reviews invasive Candida infections in pediatric SOT recipients.

[The Spanish Society of Paediatric Infectious Diseases (SEIP) recommendations on the diagnosis and management of invasive candidiasis]

Candida yeasts are ubiquitous commensals, which can cause opportunistic infection in any location of the body. The source of infection may be both endogenous and exogenous. Invasive candidiasis encompasses different entities ranging from invasive candidiasis to disseminated multiorgan infection. Invasive candidiasis is the third leading cause of nosocomial bloodstream infection and the fourth of all nosocomial infections. It is also the most common invasive fungal infection in non-neutropenic critically ill patients, with a remarkable increase in the last 20 years owing to the increased survival of these patients and to more complex diagnostic, therapeutic and surgical procedures. Its incidence in infants, according to recent reviews, stands at 38.8 cases/100,000 children younger than 1 year. Candida albicans remains the most frequent isolate in invasive infections, although infections caused by other species have risen in the last years, such as C. kruzsei, C. glabrata and C. parapsilosis; the latter causing invasive candidiasis mainly associated with central venous catheter management, especially in neonatal units. The overall mortality of invasive candidiasis is high, with 30-day mortality reaching 20-44% in some series involving paediatric patients. This report provides an update on incidence, epidemiology, clinical presentation, diagnosis, treatment and outcome of invasive infection by Candida spp. in the paediatric patient.

MALDI-TOF mass spectrometry proteomic phenotyping of clinically relevant fungi

Proteomics is particularly suitable for characterising human pathogens with high life cycle complexity, such as fungi. Protein content and expression levels may be affected by growth states and life cycle morphs and correlate to species and strain variation. Identification and typing of fungi by conventional methods are often difficult, time-consuming and frequently, for unusual species, inconclusive. Proteomic phenotypes from MALDI-TOF MS were employed as analytical and typing expression profiling of yeast, yeast-like species and strain variants in order to achieve a microbial proteomics population study. Spectra from 303 clinical isolates were generated and processed by standard pattern matching with a MALDI-TOF Biotyper (MT). Identifications (IDs) were compared to a reference biochemical-based system (Vitek-2) and, when discordant, MT IDs were verified with genotyping IDs, obtained by sequencing the 25-28S rRNA hypervariable D2 region. Spectra were converted into virtual gel-like formats, and hierarchical clustering analysis was performed for 274 Candida profiles to investigate species and strain typing correlation. MT provided 257/303 IDs consistent with Vitek-2 ones. However, amongst 26/303 discordant MT IDs, only 5 appeared "true". No MT identification was achieved for 20/303 isolates for incompleteness of database species variants. Candida spectra clustering agreed with identified species and topology of Candida albicans and Candida parapsilosis specific dendrograms. MT IDs show a high analytical performance and profiling heterogeneity which seems to complement or even outclass existing typing tools. This variability reflects the high biological complexity of yeasts and may be properly exploited to provide epidemiological tracing and infection dispersion patterns.