In vitro activities of voriconazole, posaconazole, and four licensed systemic antifungal agents against Candida species infrequently isolated from blood

A case of Candida lambica fungemia misidentified as Candida krusei in an intravenous drug abuser

Only a handful of cases of human Candida lambica infections have been published up to now. We report a Candida lambica fungemia in a young intravenous drug abuser. Using a popular chromogenic agar and a commercial phenotyping gallery, the fungus was initially misidentified as Candida krusei. Key tests to distinguish these closely related species are maximum growth temperature and assimilation of certain substrates present in more elaborate phenotyping assays. Definite confirmation is possible using molecular techniques. Susceptibility testing of the isolate demonstrated amphotericin B (MIC 0.125 microg/ml) susceptible, flucytosine (MIC 2 microg/ml) susceptible, itraconazole (MIC 0.064 microg/ml) susceptible, voriconazole (MIC 1 microg/ml) susceptible, and fluconazole (MIC >64 microg/ml, resistant).

Candidaemia with uncommon Candida species: predisposing factors, outcome, antifungal susceptibility, and implications for management

The risk factors for and clinical features of bloodstream infection with uncommon Candida spp. (species other than C. albicans, C. glabrata, C. parapsilosis, C. tropicals and C. krusei) are incompletely defined. To identify clinical variables associated with these species that might guide management, 57 cases of candidaemia resulting from uncommon Candida spp. were analysed in comparison with 517 episodes of Candida albicans candidaemia (2001-2004). Infection with uncommon Candida spp. (5.3% of candidaemia cases), as compared with C. albicans candidaemia, was significantly more likely to be outpatient-acquired than inpatient-acquired (15 of 57 vs. 65 of 517 episodes, p 0.01). Prior exposure to fluconazole was uncommon (n=1). Candida dubliniensis was the commonest species (n=22, 39%), followed by Candida guilliermondii (n=11, 19%) and Candida lusitaniae (n=7, 12%).C. dubliniensis candidaemia was independently associated with recent intravenous drug use (p 0.01) and chronic liver disease (p 0.03), and infection with species other than C. dubliniensis was independently associated with age<65 years (p 0.02), male sex (p 0.03) and human immunodeficiency virus infection (p 0.05). Presence of sepsis at diagnosis and crude 30-day mortality rates were similar for C. dubliniensis-related, non-C. dubliniensis-related and C. albicans-related candidaemia. Haematological malignancy was the commonest predisposing factor in C. guilliermondii (n=3, 27%) and C. lusitaniae (n=3, 43%) candidaemia. The 30-day mortality rate of C. lusitaniae candidaemia was higher than the overall death rate for all uncommon Candida spp. (42.9% vs. 25%, p not significant). All isolates were susceptible to amphotericin B, voriconazole, posaconazole, and caspofungin; five strains (9%) had fluconazole MIC values of 16-32 mg/L. Candidaemia due to uncommon Candida spp. is emerging among hospital outpatients; certain clinical variables may assist in recognition of this entity.

Combination of different molecular mechanisms leading to fluconazole resistance in a Candida lusitaniae clinical isolate

We report on the underlying molecular mechanisms likely responsible for the high-level fluconazole resistance in a Candida lusitaniae clinical isolate. Fluconazole resistance correlated with overexpression of ERG11 and of several efflux pump genes, in particular, the orthologs of the Candida albicans MDR1, PDR16, CDR1, CDR2, and YOR1.

Antifungal suscepitibility profile of candida spp. oral isolates obtained from denture wearers

Denture stomatitis is an inflammatory condition that occurs in denture wearers and is frequently associated with Candida yeasts. Antifungal susceptibility profiles have been extensively evaluated for candidiasis patients or immunosupressed individuals, but not for healthy Candida carriers. In the present study, fluconazole, itraconazole, voriconazole, terbinafine and 5-flucytosin were tested against 109 oral Candida spp. isolates. All antifungal agents were effective against the samples tested except for terbinafine. This work might provide epidemiological information about Candida spp. drug susceptibility in oral healthy individuals.

Susceptibility of Candida albicans to common and novel antifungal drugs, and relationship between the mating type locus and resistance, in Lebanese hospital isolates

The incidence of antifungal resistance is on the increase worldwide and novel drugs are constantly being developed to counter this trend. One hundred and sixteen clinical isolates of Candida albicans were collected from Lebanese hospitals in order to first determine the degree of resistance of Lebanese isolates to four common azoles: fluconazole (FL), itraconazole (IT), ketoconazole (KE), and voriconazole (VO), in addition to amphotericin B (AP) and caspofungin (CS) through the Epsilometer test method and second, determine any relationship between the allelic compositions of the mating type loci (MTLa, MTL alpha, MTLa/alpha) with drug resistance. Results showed that resistance, among C. albicans isolates, was the highest with 12% for IT, followed by 7.7% for VO, 6% for KE, 5% for FL, 1.7% for AP and 0% for CS. Three isolates (2.6%) were resistant to all azoles tested, including one that was resistant to all drugs used except CS. Eleven isolates were homozygous at the MTL locus (9.5%), five of which (45%) were resistant to at least one antifungal drug whereas 14 of the 105 heterozygous strains (13%) exhibited similar resistance (P = 0.02), indicating a strong correlation between MTL locus homozygosity and resistance.

Microbiological characterization of table olives commercialized in Portugal in respect to safety aspects

Table olives are a traditional component of the Mediterranean diet and are largely consumed in the world. There are different trade treatments that originate different types of olives. The aim of the present work was to proceed to the microbiological characterization of table olives commercialized in the Portuguese market, with respect to their microbiological safety. The microbiological characterization was made in the olive pulp and packing brine of thirty-five table olives samples of different types and trade treatments, namely natural olives Cv. Galega (NOG), natural turning colour olives (NTCO), green olives (GO), black ripe olives (BO) and natural olives purchased in the traditional market and obtained from traditional producers (NOt). Simultaneously it was verified specific legislation of the table olives in what it concerns to labeling rules, pH values and the identification of isolated yeasts. In general, table olives consumed showed acceptable security with exception of four NOt samples that presented Staphylococcus aureus. In a considerable number of samples high number of microorganisms indicators of contaminations were observed that reveals the need of optimization the hygienic procedures during production process to improve the quality and safety of table olives. During the work seven yeasts were isolated from olive pulp and brine.

Treatment of invasive fungal infections in clinical practice: a multi-centre survey on customary dosing, treatment indications, efficacy and safety of voriconazole

Invasive fungal infections are frequent and often deadly complications in patients with malignant hematological diseases. Voriconazole is a third generation triazole antifungal with broad activity against most clinically relevant fungal pathogens. Clinical practice often deviates from insights gained from controlled randomized trials. We conducted a multi-centre survey to evaluate efficacy, safety, treatment indications and dosing of voriconazole outside clinical trials. Patients receiving voriconazole were documented via electronic data capturing. An analysis was conducted after submission of 100 episodes from September 2004 to November 2005. Voriconazole was administered for suspected or proven invasive fungal infection (IFI) (57%), as empirical treatment in patients with fever of unknown origin (21%) and secondary (19%) as well as primary (3%) prophylaxis of IFI. Investigators’ assessment of fungal infection often diverted from EORTC/MSG 2002 criteria. A favorable response was reported in 61.4% for suspected or proven IFI and 52.4% for empirical treatment. Mortality was 15%, 26.7% of which was attributable to IFI. Breakthrough fungal infections occurred in four (21.1%) patients with voriconazole as secondary prophylaxis. Toxicity and adverse events comprised elevated liver enzymes and visual disturbances. Although indications frequently deviated from clinical evidence and legal approval, voriconazole showed efficacy and safety, comparable to major controlled clinical trials. Data from this survey demonstrate the difficulty of putting drugs to their approved use in IFI.

Candida lusitaniae septic arthritis: case report and review of the literature

Candida lusitaniae is an infrequently encountered Candida species that has been associated with resistance to amphotericin B. We present a case of septic arthritis with C. lusitaniae and provide a brief review of the organism, especially in regard to current information about its pattern of resistance to antifungal agents.

Attachment and entry of Candida famata in monocytes and epithelial cells

Candida albicans is considered the main pathogenic yeast responsible for a multitude of infective disorders. However, other yeasts, such as Candida famata, are being recognized as potential emerging pathogens that cause several types of infections in humans and animals. Consequently, we have investigated the adhesion and internalization of Candida famata into monocytes and epithelial cells. The interaction of the yeast with the cells is very rapid and takes place during the first 15 min of injection. However, the affinity of the yeast for the cells varies, THP-1 (human monocytes) being the highest and followed in decreasing order by HeLa (human carcinoma), HaCaT, and Pam-212 (human and mouse keratinocytes, respectively). Heat inactivation or treatment with nystatin, significantly decreases yeast adhesion to cells. Immunofluorescence, as well as scanning and transmission electron microscopy, reveals that cell lines are able to internalize C. famata. At 48 h after infection, most of the yeasts located inside cells appear degraded, but some yeasts recovered from lysed cells, were still viable. Adhesion and internalization of C. famata into HeLa cells were found to be lower than those of C. albicans and C. glabrata, but higher than those of S. cerevisiae. In addition, infection with C. famata results in actin microfilaments rearrangement. This article presents novel data in the interaction of this pathogenic yeast with mammalian cells.

Candida krusei, a multidrug-resistant opportunistic fungal pathogen: geographic and temporal trends from the ARTEMIS DISK Antifungal Surveillance Program, 2001 to 2005

Candida krusei is well known as a fungal pathogen for patients with hematologic malignancies and for transplant recipients. Using the ARTEMIS Antifungal Surveillance Program database, we describe geographic and temporal trends in the isolation of C. krusei from clinical specimens and the in vitro susceptibilities of 3,448 isolates to voriconazole as determined by CLSI (formerly NCCLS) disk diffusion testing. In addition, we report the in vitro susceptibilities of bloodstream infection isolates of C. krusei to amphotericin B (304 isolates), flucytosine (254 isolates), anidulafungin (121 isolates), caspofungin (300 isolates), and micafungin (102 isolates) as determined by CLSI broth microdilution methods. Geographic differences in isolation were apparent; the highest frequency of isolation was seen for the Czech Republic (7.6%) and the lowest for Indonesia, South Korea, and Thailand (0 to 0.3%). Overall, 83% of isolates were susceptible to voriconazole, ranging from 74.8% in Latin America to 92.3% in North America. C. krusei was most commonly isolated from hematology-oncology services, where only 76.7% of isolates were susceptible to voriconazole. There was no evidence of increasing resistance of C. krusei to voriconazole from 2001 to 2005. Decreased susceptibilities to amphotericin B (MIC at which 90% of isolates were inhibited [MIC(90)], 4 microg/ml) and flucytosine (MIC(90), 16 microg/ml) were noted, whereas 100% of isolates were inhibited by < or =2 microg/ml of anidulafungin (MIC(90), 0.06 microg/ml), micafungin (MIC(90), 0.12 microg/ml) or caspofungin (MIC(90), 0.25 microg/ml). C. krusei is an uncommon but multidrug-resistant fungal pathogen. Among the systemically active antifungal agents, the echinocandins appear to be the most active against this important pathogen.

Yeast identification--past, present, and future methods

The focus of this review is the evolution of biochemical phenotypic yeast identification methods with emphasis on conventional approaches, rapid screening tests, chromogenic agars, comprehensive commercial methods, and the eventual migration to genotypic methods. As systemic yeast infections can be devastating and resistance is common in certain species, accurate identification to the species level is paramount for successful therapy and appropriate patient care.

In vitro susceptibility to posaconazole of 1,903 yeast isolates recovered in France from 2003 to 2006 and tested by the method of the European committee on antimicrobial susceptibility testing

The posaconazole MIC(90) for 1,903 yeast isolates from France was 1 microg/ml (range, < or =0.015 to 8 microg/ml). Ninety percent of isolates with fluconazole MICs of > or =8 microg/ml (n = 509) and 90% of those with voriconazole MICs of > or =2 microg/ml (n = 80) were inhibited by 2 and 8 microg/ml of posaconazole, respectively.

Posaconazole susceptibility testing against Candida species: comparison of broth microdilution and E-test methods

Posaconazole (POS) is a newer triazole with activity against yeasts and moulds. POS and fluconazole were tested in vitro against 32 Candida albicans, 30 C. glabrata, 21 C. tropicalis, 29 C. krusei, 28 C. parapsilosis, 50 C. inconspicua, 13 C. kefyr and 5 C. famata isolates using CLSI broth microdilution method (BMD). We compared E-test and a modified BMD using polyethylene-glycol (PEG) as solvent to the CLSI method. BMDs and E-test were performed according to CLSI and the manufacturer's instructions respectively. Geometric means of POS MICs using BMD were 0.71, 0.22 and 0.21 microg ml(-1) against C. glabrata, C. krusei and C. inconspicua, respectively, and remained below 0.1 microg ml(-1) against all other species tested. One of two C. albicans and two of three C. glabrata isolates resistant to fluconazole showed MICs above 8 microg ml(-1) to POS. The impact of using PEG instead of DMSO had only a minor effect (agreements above 95% with the exception of C. parapsilosis). E-tests read after 24 h showed good agreement with the BMD. POS exhibited excellent in vitro activity against Hungarian Candida strains. E-test showed good correlation with the CLSI method, but to facilitate the comparability of results we believe that DMSO should be used as solvent in the BMD.

Evolution of antibody response and fungal antigens in the serum of a patient infected with Candida famata

The presence of fungal antibodies and antigens in the serum of a patient diagnosed in 1996 with acute zonal occult outer retinopathy caused by Candida famata infection was examined. Antibodies against C. famata increased until 1999–2000 when antifungal treatment was initiated. The antibodies were detected by ELISA and immunofluorescence analysis using C. famata. These antibodies were not immunoreactive against several Candida species tested. Positive immunofluorescence was obtained with IgM, but not IgA, IgG or IgE. Moreover, the IgM response disappeared several months after treatment with antifungal compounds, despite the fact that C. famata antigens were present in the blood. Finally, a sensitive test was developed to assay for the presence of C. famata antigens in serum based on the immunodetection of fungal antigens transferred to a nitrocellulose membrane and incubated with rabbit antibodies raised against C. famata. According to this method, the infection diminished with antifungal treatment.

Antifungal drug susceptibility profile of Pichia anomala isolates from patients presenting with nosocomial fungemia

In vitro susceptibility of 58 isolates of Pichia anomala to five antifungal drugs using two broth microdilution methods (CLSI and EUCAST) was analyzed. Low susceptibility to itraconazole was observed. Fluconazole, voriconazole, amphotericin B, and caspofungin showed good antifungal activity, although relatively high drug concentrations were necessary to inhibit the isolates.

Oral candidiasis and oral yeast carriage among institutionalised South African paediatric HIV/AIDS patients

South Africa currently has an estimated 500,000 AIDS orphans, many of whom are HIV-positive. Oral candidiasis commonly occurs in both adult and paediatric HIV/AIDS patients. Published information on HIV-positive children in Africa mainly concerns hospitalised patients. The objective of this study was to determine the prevalence of oral candidiasis and oral yeast carriage among paediatric HIV/AIDS patients residing in orphanages in Gauteng, South Africa, and to compare the prevalence of isolated yeast species with species obtained from adult HIV/AIDS patients. Eighty-seven paediatric HIV/AIDS patients residing in five homes were examined and a swab taken from the dorsal surface of the tongue, cultured on CHROMagar and yeast isolates identified with the ATB 32C commercial system. The species prevalence of 57 identified isolates was compared with that of 330 isolates from adult HIV/AIDS patients. Twelve (13.8%) children presented with clinically detectable candidiasis. Yeasts were isolated from 0% to 53% of children in the individual homes, with Candida albicans (40.4%) and C. dubliniensis (26.3%) constituting the most frequently isolated species. Gentian violet prophylaxis was administered in one particular home and a higher carriage rate (66.6%) of non-C. albicans and non-C. dubliniensis was observed among these children. The prevalence of C. albicans was lower while the prevalence of C. dubliniensis, C. glabrata and C. tropicalis was significantly higher (p < or = 0.001) among the children than among adult HIV/AIDS patients. These findings indicate a role for yeast culture and species determination in cases with candidiasis in institutionalized paediatric HIV/AIDS patients.

Posaconazole: clinical pharmacology and potential for management of fungal infections

Posaconazole is a novel lipophilic antifungal triazole that inhibits cytochrome P450-dependent 14-alpha demethylase in the biosynthetic pathway of ergosterol. Inhibition of this enzyme leads to an accumulation of toxic 14-alpha methylsterols and a depletion of ergosterol, resulting in a perturbation of the function of the fungal cell membrane and blockage of cell growth and division. In vitro, posaconazole has potent and broad-spectrum activity against opportunistic, endemic and dermatophytic fungi. This activity extends to organisms that are often refractory to existing triazoles, amphotericin B or echinocandins, such as Candida glabrata, Candida krusei, Aspergillus terreus, Fusarium spp. and the Zygomycetes. A large variety of animal models of invasive fungal infections have provided consistent evidence of efficacy against these organisms in vivo, both in normal and immunocompromised animals. Posaconazole is available as an oral suspension and optimal exposure is achieved when the drug is administered in two to four divided doses along with food or a nutritional supplement. The compound has a large volume of distribution, in the order of 5 l/kg, and a half-life of approximately 20 h. Posaconazole is not metabolized to a significant extent through the cytochrome P450 enzyme system and is primarily excreted in an unchanged form in the feces. Although it is inhibitory, cytochrome P3A4 has no effect on 1A2, 2C8, 2C9, 2D6 and 2E1 isoenzymes, and therefore, a limited spectrum of drug-drug interactions can be expected. Pharmacokinetic studies in special populations revealed no necessity for dosage adjustment based on differences in age, gender, race, renal or hepatic function. Posaconazole has demonstrated strong antifungal efficacy in Phase II and III clinical trials in immunocompromised patients with oropharyngeal and esophageal candidiasis. Posaconazole also showed promising efficacy as salvage therapy in a large Phase II study including 330 patients with invasive fungal infections intolerant to or refractory to standard therapies. Posaconazole appears to be well tolerated in a manner comparable with that of fluconazole and it is currently under regulatory review in the USA and Europe for the treatment of refractory invasive fungal infections. This drug profile reviews the preclinical and clinical pharmacology of posaconazole and its potential role for prevention and treatment of invasive fungal infections.

Posaconazole Oral Suspension

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Antifungal resistance in Candida spp. isolated in Italy between 2002 and 2005 from children and adults

The activity of amphotericin B, fluconazole, flucytosine, itraconazole and voriconazole was tested in vitro against 618 clinical Candida spp. isolates, using the broth microdilution or the disk diffusion method (voriconazole). Amphotericin B and voriconazole were the most potent antifungal agents assayed (100% of susceptible strains). Resistance to fluconazole and itraconazole was detected in three (0.7%) and 11 (2.7%) isolates of Candida albicans and in four (3.7%) isolates of Candida glabrata. Flucytosine intermediate, resistant strains, or both, were observed in C. albicans (0.3% and 0.7%), C. glabrata (2.8% intermediate) and C. tropicalis (15.2% and 15.2%). C. krusei was the least susceptible species to azoles. No statistically significant differences in the rates of resistant isolates depending on site of infection and age of the patient were observed, with the exception of C. albicans and itraconazole (higher percentage of resistance in children). At present, acquired antifungal resistance represents an uncommon finding in most Candida spp. circulating in Northern Italy.

Strain typing and determination of population structure of Candida krusei by multilocus sequence typing

A multilocus sequence typing (MLST) scheme for Candida krusei was devised, based on sequencing of six gene fragments of the species. The existence of heterozygous results for each of the six fragments sequenced confirms that C. krusei is diploid for at least part of its genome. The C. krusei MLST scheme had a discriminatory index of 0.998, making this system ideal for strain typing of C. krusei clinical isolates. MLST data for 122 independent C. krusei isolates from a range of geographical sources were analyzed by eBURST, structure, and the unweighted-pair group method using average linkages to derive a population structure comprising four subtype strain clusters. There was no evidence of geographical associations with particular subtypes. Data for pairs of isolates from seven patients showed that each patient was colonized and/or infected with strain types that were indistinguishable by MLST. The C. krusei MLST database can be accessed online at http://pubmlst.org/ckrusei/.

Fluconazole and itraconazole susceptibilities of Candida spp. isolated from oropharyngeal specimens and blood cultures of paediatric haematology/oncology patients

This study examined the in vitro susceptibilities to fluconazole and itraconazole of isolates of Candida spp. from surveillance oropharyngeal specimens and blood cultures from paediatric patients with malignancy. The species distribution of 100 isolates from oropharyngeal specimens was C. albicans 86%, C. glabrata 7%, C. lusitaniae 4%, C. parapsilosis 2% and C. tropicalis 1%. From a total of nine isolates from blood cultures the species distribution was C. albicans 33.3%, C. parapsilosis 33.3 % and C. guilliermondii 33.3%. Only three of the oropharyngeal isolates were resistant to fluconazole (MIC > or = 64 mg l(-1)) and only two were resistant to itraconazole (MIC > or = 1 mg l(-1)). None of the blood culture isolates was resistant to either agent. At this centre, C. albicans is the predominant species from oropharyngeal specimens, but non-albicans Candida species predominate in blood cultures. Although resistance to fluconazole and itraconazole is rare at present, continued surveillance is warranted to monitor trends in species distribution and antifungal susceptibility.

Killing kinetics of caspofungin, micafungin, and amphotericin B against Candida guilliermondii

Amphotericin B (AMB), micafungin, and caspofungin MICs, minimal fungicidal concentrations, and time-killing curves were determined in the presence and absence of 10% inactivated serum. AMB was the only agent with consistent killing activity (time required to achieve 99.9% of growth reduction was 2.1 to 3.2 h). The presence of serum enhanced caspofungin activity but lowered those of micafungin and AMB.

Epidemiological study of Candida infections in blood: susceptibilities of Candida spp. to antifungal agents, and clinical features associated with the candidemia

The purpose of this study was to evaluate the susceptibility to antifungal agents of Candida spp. isolated from blood samples from patients in our hospital, located in Osaka, Japan. We also examined the clinical background of these patients. We analyzed fungi isolated from clinical blood samples obtained in our hospital over a period of 10 years (1993 to 2002). Antifungal susceptibility testing was carried out for six agents, using the National Committee of Clinical Laboratory Standards (NCCLS) M-27-A2 method. The clinical backgrounds were reviewed using the medical records of 125 patients who were diagnosed as having candidemia. The major fungi isolated were Candida parapsilosis (39.2%) and C. albicans (30.1%), and both were sensitive to fluconazole. One strain of C. glabrata and six strains of C. krusei were resistant to fluconazole, and they constituted 4.4% of all Candida spp. isolated. With the exception of C. parapsilosis, most fungi were susceptible to micafungin, although there is no universally agreed breakpoint for this drug. Analysis of the patients' clinical backgrounds revealed that the major underlying disease was cancer (46.4% excluding hematological malignancies). C. krusei was detected almost exclusively in patients with hematological malignancies. Indwelling venous catheters had been responsible for infection in 93.6% of the infected patients. The clinical outcomes of the 125 patients were favorable in 52% and poor in 48%, and subsequent removal of the indwelling catheters was effective in about half of the patients in whom this was done, with good prognosis. To prevent mycosis and its complications, indwelling catheters should be avoided as much as possible. Attention must be paid to the possibility that resistant isolates of Candida spp. can be selected as a result of the use of antifungal agents.

Protective immune responses against systemic candidiasis mediated by phage-displayed specific epitope of Candida albicans heat shock protein 90 in C57BL/6J mice

Specific epitope (DEPAGE) of Candida albicans heat shock protein 90 (SE-CA-HSP90) was successfully expressed on the surface of filamentous phage fd, fused to the major coat protein pVIII. Protective immune responses mediated by hybrid-phage expressing SE-CA-HSP90 in C57BL/6J mice were evaluated in this paper. The results showed that hybrid-phage particles induced the specific antibody response against SE-CA-HSP90, enhanced delayed-type hypersensitivity (DTH) response, natural killer (NK) cell activity and concanavalin A (ConA)-induced splenocyte proliferation. Furthermore, this study demonstrated that hybrid-phage-immunized mice had fewer colony forming unites (CFU) in the kidneys compared with wild-type phage-immunized mice and TE (1.0mM EDTA, 0.01M Tris-HCl, pH 8.0)-injected mice and showed statistically significant survival advantage over TE-injected group. In conclusion, the results suggest that the hybrid-phage displaying SE-CA-HSP90 may be considered as a potential candidate for producing vaccines against systemic candidiasis.

Invasive fungal infections: a review of epidemiology and management options

Fungi are increasingly recognised as major pathogens in critically ill patients. Candida spp. and Cryptococcus spp. are the yeasts most frequently isolated in clinical practice. The most frequent filamentous fungi (moulds) isolated are Aspergillus spp., but Fusarium spp., Scedosporium spp., Penicillium spp., and Zygomycetes are increasingly seen. Several reasons have been proposed for the increase in invasive fungal infections, including the use of antineoplastic and immunosuppressive agents, broad-spectrum antibiotics, and prosthetic devices and grafts, and more aggressive surgery. Patients with burns, neutropenia, HIV infection and pancreatitis are also predisposed to fungal infection. The epidemiology and clinical features of fungal infections are reviewed, together with antifungal agents currently or soon to be available.

Species Distribution and Antifungal Susceptibility Profile of Oral Candida Isolates from HIV-infected Patients in the Antiretroviral Therapy Era

In this study, we investigated the yeasts colonization of genus Candida, including C. dubliniensis, isolated of HIV-infected patients oral cavities and we accessed in vitro susceptibility pattern of the Candida isolates to four antifungal agents. Out of 99 patients investigated, 62 (62.6%) were colonized with yeasts. C. albicans was the prevailing species (50%). C. dubliniensis isolates were not recovered in our study. We verified that 8.1% of the yeasts isolated were resistant to fluconazole, 8.1% to itraconazole and 3.2% to voriconazole. The isolates demonstrated very low voriconazole MICs, in which 79% (49/62) presented values of 0.015 mug/ml. All Candida isolates were susceptible to amphotericin B. The results reported here showed that although C. albicans continues to be present in one-half of oral Candida carriage of HIV-infected patients, Candida non-albicans species are increasing among these patients. Besides, the findings of resistant isolates endorse the role of antifungal susceptibility testing whenever antifungal treatment with azoles is planned.

Candida guilliermondii fungemia in patients with hematologic malignancies

The microbiological, clinical, and epidemiological features of most non-Candida albicans Candida species are well known, but much less is known about species such as Candida guilliermondii, an uncommon pathogen causing a variety of deep-seated infections in immunocompromised hosts. To characterize C. guilliermondii fungemia in patients with hematological malignancies and its susceptibility to antifungal drugs, all cases of C. guilliermondii fungemia diagnosed in our department between 1983 and 2005 were retrospectively analyzed and the literature was reviewed. C. guilliermondii caused 29/243 (11.7%) candidemia episodes diagnosed during the study period. Central venous catheters were the documented sources of candidemia in 19/29 episodes (65.5%), and invasive tissue infections were documented in 2 (6.9%). In the remaining eight, the catheter was not removed and the source of the fungemia remained obscure. Seven episodes ended in death, but only one could be attributed to invasive C. guilliermondii infection. Molecular typing data reveal no evidence of common infection sources. Isolates displayed high rates of in vitro susceptibility to amphotericin B (100%), voriconazole (95%), and fluconazole (90%) and lower rates of in vitro susceptibility to flucytosine (86%), itraconazole (76%), and caspofungin (33%). Our literature review confirms that C. guilliermondii is a significantly more frequent cause of candidemia among cancer patients compared with the general hospital population. It accounted for <1% of the total number of Candida bloodstream isolates reported in the articles we reviewed, with higher rates in Europe (1.4%) and Asia (1.8%) compared with North America (0.3%).

Perfil de sensibilidad antifúngica de especies de Candida aisladas de hemocultivos en un Hospital Universitario, Maracaibo, Venezuela

The aim of this study was to determine the in vitro susceptibility of amphotericin B, fluconazole and itraconazole, to several Candida spp recovered from blood cultures on hospitalized patients at the University Hospital of Maracaibo, Venezuela. The determination of the antifungal susceptibility was carried out according to the microdilution method in broth developed by The European Committee for Antimicrobial Susceptibility Testing (EUCAST). The profile of susceptibility of the 74 isolates showed that all the studied species were susceptible to amphotericin B, and 97.2% and 89.2% to fluconazole and itraconazole, respectively.

Intrinsic in vitro susceptibility of primary clinical isolates of Aspergillus fumigatus, Aspergillus terreus, Aspergillus nidulans, Candida albicans and Candida lusitaniae against amphotericin B

A total of 60 clinical fungal isolates from patients without prior amphotericin B treatment and three control strains were evaluated for their intrinsic susceptibility to amphotericin B (AmB) using microdilution, Etest and disc diffusion assays, on three media each, Roswell Park Memorial Institute (RPMI) 1640, Antibiotic Medium 3 (AM3) and High Resolution Medium. The fungal strains included isolates of Aspergillus fumigatus (n = 10), Aspergillus terreus (n = 12), Aspergillus nidulans (n = 9), Candida albicans (n = 6) and Candida lusitaniae (n = 23). The A. terreus strains were significantly less susceptible to AmB than the A. fumigatus strains in all nine experimental settings (P-values ranging from 0.009 to <0.00001). The A. nidulans strains were equally susceptible to AmB as the A. fumigatus strains in seven of nine experimental settings and less susceptible in two (microdilution performed on RPMI and AM3, P = 0.01 and 0.007). The C. lusitaniae strains were equally susceptible to AmB as the C. albicans strains in seven of nine experimental settings and more susceptible in two (microdilution and Etest, both performed on AM3, P = 0.01 and 0.0002). Thus, we confirmed that A. terreus is intrinsically less susceptible to AmB than A. fumigatus. In contrast, nine German clinical isolates of Aspergillus nidulans were found equally susceptible to AmB as 10 isolates of A. fumigatus. Furthermore, we found 23 German clinical isolates of C. lusitaniae from patients without prior treatment with AmB equally susceptible to AmB as C. albicans.

Presumptive identification of Candida species other than C. albicans, C. krusei, and C. tropicalis with the chromogenic medium CHROMagar Candida

Background

CHROMagar Candida (CaC) is increasingly being reported as a medium used to differentiate Candida albicans from non-albicans Candida (NAC) species. Rapid identification of NAC can assist the clinician in selecting appropriate antifungal therapy. CaC is a differential chromogenic medium designed to identify C. albicans, C. krusei, and C. tropicalis based on colony color and morphology. Some reports have proposed that CaC can also reliably identify C. dubliniensis and C. glabrata.

Methods

We evaluated the usefulness of CaC in the identification of C. dubliniensis, C. famata, C. firmetaria, C. glabrata, C. guilliermondii, C. inconspicua, C. kefyr, C. lipolytica, C. lusitaniae, C. norvegensis, C. parapsilosis, and C. rugosa.

Results

Most NAC produced colonies that were shades of pink, lavender, or ivory. Several isolates of C. firmetaria and all C. inconspicua produced colonies difficult to differentiate from C. krusei. Most C. rugosa isolates produced unique colonies with morphology like C. krusei except in a light blue-green color. C. glabrata isolates produced small dark violet colonies that could be differentiated from the pink and lavender colors produced by other species. All seventeen isolates of C. dubliniensis produced green colonies similar to those produced by C. albicans.

Conclusion

C. glabrata and C. rugosa appear distinguishable from other species using CaC. Some NAC, including C. firmetaria and C. inconspicua, could be confused with C. krusei using this medium.

Successful treatment of fungus balls due to fluconazole-resistant Candida sake obstructing ureter stents in a renal transplant patient

Reported here is the case of a 72-year-old renal transplant recipient with stenosis of the neo-ureter requiring stents, who was admitted to hospital with pyonephrosis caused by fungus balls. Fluconazole-resistant Candida sake was grown. Treatment with external drainage of the renal pelvis and intravenous and local administration of caspofungin resulted in relief of the obstruction. Eradication of the infection was achieved by surgical removal of the ureter with all stents and construction of a cysto-pyelostomy.

Results from the ARTEMIS DISK Global Antifungal Surveillance Study: a 6.5-year analysis of susceptibilities of Candida and other yeast species to fluconazole and voriconazole by standardized disk diffusion testing

Fluconazole in vitro susceptibility test results for 140,767 yeasts were collected from 127 participating investigators in 39 countries from June 1997 through December 2003. Data were collected on 79,343 yeast isolates tested with voriconazole from 2001 through 2003. All investigators tested clinical yeast isolates by the CLSI (formerly NCCLS) M44-A disk diffusion method. Test plates were automatically read and results were recorded with the BIOMIC Vision Image Analysis System. Species, drug, zone diameter, susceptibility category, and quality control results were collected quarterly via e-mail for analysis. Duplicate (the same patient, same species, and same susceptible-resistant biotype profile during any 7-day period) and uncontrolled test results were not analyzed. The 10 most common species of yeasts all showed less resistance to voriconazole than to fluconazole. Candida krusei showed the largest difference, with over 70% resistance to fluconazole and less than 8% to voriconazole. All species of yeasts tested were more susceptible to voriconazole than to fluconazole, assuming proposed interpretive breakpoints of > or =17 mm (susceptible) and < or =13 mm (resistant) for voriconazole. MICs reported in this study were determined from the zone diameter in millimeters from the continuous agar gradient around each disk, which was calibrated with MICs determined from the standard CLSI M27-A2 broth dilution method by balanced-weight regression analysis. The results from this investigation demonstrate the broad spectrum of the azoles for most of the opportunistic yeast pathogens but also highlight several areas where resistance may be progressing and/or where previously rare species may be "emerging."

[In vitro susceptibility of fungal and yeast clinical isolates to itraconazole and voriconazole]

The interest on the in vitro susceptibility to itraconazole has recently increased due the availability of the intravenous formulation. In this study, comparative MICs of this antifungal with voriconazole were carried out in 62 clinical isolates of filamentous fungi and 100 yeasts isolates using the NCCLS microbroth methods described in M38-A and M27-A2 documents. A MIC90 of 0.125 micrograms per ml was observed for itraconazole and voriconazole against Aspergillus fumigatus. Higher susceptibility to itraconazole was found for the filamentous form of Sporotrhix schenckii (p = 0.001). Voriconazole was more effective against Scedosporium apiospermium while Scedosporium prolificans isolates were resistant to both azoles. Some isolates of Rhizopus stolonifer were susceptible to itraconazole and resistant to voriconazole, but without statistical significance. Susceptibility of nine species of Candida was similar for both triazoles used in this study. However, Candida glabrata was more susceptible to voriconazole. Some fluconazole-resistant Candida albicans isolates were susceptible to itraconazole and / or voriconazole. Cryptococcus neoformans was more susceptible to itraconazole than to voriconazole. Itraconazole and voriconazole showed very close in vitro activity against the tested fungal isolated, except against S. schenckii. In spite of this, there were some differences in susceptibility among isolates within the same fungal species.

Voriconazole versus a regimen of amphotericin B followed by fluconazole for candidaemia in non-neutropenic patients: a randomised non-inferiority trial

BACKGROUND

Voriconazole has proven efficacy against invasive aspergillosis and oesophageal candidiasis. This multicentre, randomised, non-inferiority study compared voriconazole with a regimen of amphotericin B followed by fluconazole for the treatment of candidaemia in non-neutropenic patients.

METHODS

Non-neutropenic patients with a positive blood culture for a species of candida and clinical evidence of infection were enrolled. Patients were randomly assigned, in a 2:1 ratio, either voriconazole (n=283) or amphotericin B followed by fluconazole (n=139). The primary efficacy analysis was based on clinical and mycological response 12 weeks after the end of treatment, assessed by an independent data-review committee unaware of treatment assignment.

FINDINGS

Of 422 patients randomised, 370 were included in the modified intention-to-treat population. Voriconazole was non-inferior to amphotericin B/fluconazole in the primary efficacy analysis, with successful outcomes in 41% of patients in both treatment groups (95% CI for difference -10.6% to 10.6%). At the last evaluable assessment, outcome was successful in 162 (65%) patients assigned voriconazole and 87 (71%) assigned amphotericin B/fluconazole (p=0.25). Voriconazole cleared blood cultures as quickly as amphotericin B/fluconazole (median time to negative blood culture, 2.0 days). Treatment discontinuations due to all-cause adverse events were more frequent in the voriconazole group, although most discontinuations were due to non-drug-related events and there were significantly fewer serious adverse events and cases of renal toxicity than in the amphotericin B/fluconazole group.

INTERPRETATION

Voriconazole was as effective as the regimen of amphotericin B followed by fluconazole in the treatment of candidaemia in non-neutropenic patients, and with fewer toxic effects.

RELEVANCE TO PRACTICE

There are several options for treatment of candidaemia in non-neutropenic patients, including amphotericin B, fluconazole, voriconazole, and echinocandins. Voriconazole can be given both as initial intravenous treatment and as an oral stepdown agent.

Isolation of Candida famata from a patient with acute zonal occult outer retinopathy

The etiology of a number of retinopathies, such as acute zonal occult outer retinopathy (AZOOR), remains undetermined. Candida famata was isolated from conjunctival exudates of a patient diagnosed with AZOOR. This yeast was very abundant, particularly in the more affected eye, while no other pathogens or fungal species were in evidence. Immunological tests revealed the presence of antigen-specific T lymphocytes by using C. famata as a challenge. Moreover, enzyme-linked immunosorbent assay analysis showed the presence of specific antibodies against this yeast in the patient's blood. Delayed hypersensitivity by use of a skin test was also positive. Finally, antifungal treatments led to improvements in several clinical symptoms, including funduscopic analysis. However, despite prolonged treatment with fluconazole and itraconazole, C. famata still appeared in the conjunctival exudates. The new antifungal voriconazole may represent a better choice for treatment.

Intravenous Voriconazole Therapy in a Preterm Infant

A preterm infant younger than 3 months developed a disseminated fluconazole-resistant Candida albicans infection that was treated with liposomal amphotericin B for 52 days, followed by the combination of intravenous voriconazole and liposomal amphotericin B for an additional 19 days. The infant received concomitant phenobarbital throughout the hospital stay. The infection resolved after addition of voriconazole to the treatment regimen. Intravenous voriconazole was begun at a high dosage, 6 mg/kg every 12 hours, for anticipated developmental and drug-induced changes in volume of distribution and clearance. On day 4 of therapy, serum concentrations of voriconazole were 3.27 microg/ml immediately after infusion and 0.33 microg/ml 6 hours after infusion. These levels were significantly lower than those achieved in adult pharmacokinetic and safety studies. After the infant's dosage was increased to 6 mg/kg every 8 hours, serum concentrations were 5.33 microg/ml 30 minutes after infusion and 2.67 microg/ml 6 hours after infusion. These levels were similar to those observed in adults. Intravenous voriconazole 6 mg/kg every 8 hours was administered safely, with concomitant phenobarbital therapy, in this preterm infant with developmentally diminished renal function.

Candida prosthetic valve endocarditis cured by caspofungin therapy without valve replacement

A 64-year-old woman with a mechanical mitral valve prosthesis developed late-onset Candida endocarditis. Blood cultures grew Candida glabrata and Candida krusei. Transesophageal echocardiography demonstrated vegetations on the valve. The patient was not medically fit for valve replacement, but her condition was successfully treated with 6 weeks of intravenous caspofungin therapy.

Antifungal susceptibilities of clinical isolates of Candida species, Cryptococcus neoformans, and Aspergillus species from Taiwan: surveillance of multicenter antimicrobial resistance in Taiwan program data from 2003

The susceptibilities of nonduplicate isolates to six antifungal agents were determined for 391 blood isolates of seven Candida species, 70 clinical isolates (from blood or cerebrospinal fluid) of Cryptococcus neoformans, and 96 clinical isolates of four Aspergillus species, which were collected in seven different hospitals in Taiwan (as part of the 2003 program of the study group Surveillance of Multicenter Antimicrobial Resistance in Taiwan). All isolates of Candida species other than C. glabrata and C. krusei were susceptible to fluconazole. Among the 59 C. glabrata isolates, 16 (27%) were not susceptible to fluconazole, and all were dose-dependently susceptible or resistant to itraconazole. For three (5.1%) C. glabrata isolates, voriconazole MICs were 2 to 4 microg/ml, and for all other Candida species isolates, voriconazole MICs were </=0.5 microg/ml. The proportions of isolates for which amphotericin B MICs were >/=2 microg/ml were 100% (3 isolates) for C. krusei, 11% (23 of 207 isolates) for Candida albicans, 3.0% (2 of 67 isolates) for Candida tropicalis, 20% (12 of 59 isolates) for C. glabrata, and 0% for both Candida parapsilosis and Candida lusitaniae. For three (4%) Cryptococcus neoformans isolates, fluconazole MICs were >/=16 microg/ml, and two (3%) isolates were not inhibited by 1 mug of amphotericin B/ml. For four (4.2%) of the Aspergillus isolates, itraconazole MICs were 8 microg/ml. Aspergillus flavus was less susceptible to amphotericin B, with the MICs at which 50% (1 microg/ml) and 90% (2 microg/ml) nsrsid417869\delrsid7301351 of isolates were inhibited being twofold greater than those for Aspergillus fumigatus and Aspergillus niger. All Aspergillus isolates were inhibited by </=1 microg of voriconazole/ml, including isolates with increased resistance to amphotericin B and itraconazole. This study revealed the emergence in Taiwan of decreased susceptibilities of Candida species to amphotericin B and of C. neoformans to fluconazole and amphotericin B. Voriconazole was the most potent agent against the fungal isolates tested, including fluconazole- and amphotericin B-nonsusceptible strains.

Actividad in vitro del voriconazol, fluconazol, itraconazol y anfotericina B contra levaduras no Candida albicans

Antifungal susceptibility testing was performed on 197 yeast isolates from the BCCM/IHEM biomedical fungi and yeasts collection (Belgian Co-ordinated Collections of Micro-organisms / IPH-Mycology) to study the in vitro activity of voriconazole against fluconazole, itraconazole and amphotericin B. MICs of the four antifungal agents were determined by an adapted NCCLS M27-A microdilution reference method. MIC readings were visually and spectrophotometrically determined. Optical density data were used for calculation of the MIC endpoints. For amphotericin B, the MIC endpoint was defined as the minimal antifungal concentration that exerts 90% inhibition, compared to the control growth. The azoles endpoints were determined at 50% inhibition of growth. The MIC distribution of voriconazole susceptibilities showed that 193 isolates had a MIC < or = 2 microg/ml and 185 a MIC < or = 1 microg/ml. Cross-tabulation of voriconazole, fluconazole, and itraconazole MICs indicated that voriconazole MICs raised with fluconazole and itraconazole MICs. The in vitro data obtained in this study suggest that voriconazole may also be effective treating yeast infection in patients infected with fluconazole or itraconazole resistant isolates.

Antifungal activity of posaconazole compared with fluconazole and amphotericin B against yeasts from oropharyngeal candidiasis and other infections

OBJECTIVES

The in vitro antifungal activity of posaconazole was compared with that of fluconazole and amphotericin B.

MATERIALS AND METHODS

A microdilution method (M27-A2) was used with 331 clinical yeast isolates.

RESULTS

The geometric mean MICs of posaconazole, fluconazole and amphotericin B were 0.16, 0.91 and 0.15 mg/L, respectively. Posaconazole was markedly more active than fluconazole and was active against 9/11 fluconazole-resistant Candida albicans, and five Candida glabrata had an MIC of posaconazole of 16 mg/L.

CONCLUSIONS

These data indicate that posaconazole is a potentially effective antifungal agent for the treatment of mycoses caused by yeasts.

Fluconazole-resistant pathogens Candida inconspicua and C. norvegensis: DNA sequence diversity of the rRNA intergenic spacer region, antifungal drug susceptibility, and extracellular enzyme production

The opportunistic fungal pathogens Candida inconspicua and C. norvegensis are very rarely isolated from patients and are resistant to fluconazole. We collected 38 strains of the two microorganisms isolated from Europe and Japan, and compared the polymorphism of the rRNA intergenic spacer (IGS) and internal transcribed spacer (ITS) regions, antifungal drug susceptibility, and extracellular enzyme production as a potential virulence factor. While the IGS sequences of C. norvegensis were not very divergent (more than 96.7% sequence similarity among the strains), those of C. inconspicua showed remarkable diversity, and were divided into four genotypes with three subtypes. In the ITS region, no variation was found in either species. Since the sequence similarity of the two species is approximately 70% at the ITS region, they are closely related phylogenetically. Fluconazole resistance was reconfirmed for the two microorganisms but they were susceptible to micafungin and amphotericin B. No strain of either species secreted aspartyl proteinase or phospholipase B. These results provide basal information for accurate identification, which is of benefit to global molecular epidemiological studies and facilitates our understanding of the medical mycological characteristics of C. inconspicua and C. norvegensis.

Aspergillus infections in transplant recipients

Aspergillus infections are occurring with an increasing frequency in transplant recipients. Notable changes in the epidemiologic characteristics of this infection have occurred; these include a change in risk factors and later onset of infection. Management of invasive aspergillosis continues to be challenging, and the mortality rate, despite the use of newer antifungal agents, remains unacceptably high. Performing molecular studies to discern new targets for antifungal activity, identifying signaling pathways that may be amenable to immunologic interventions, assessing combination regimens of antifungal agents or combining antifungal agents with modulation of the host defense mechanisms, and devising diagnostic assays that can rapidly and reliably diagnose infections represent areas for future investigations that may lead to further improvement in outcomes.

Susceptibility of filamentous fungi to voriconazole tested by two microdilution methods

The growing number of fungal infections, coupled with emerging resistance to classical antifungal agents, has led to the development of new agents, among them voriconazole. Susceptibility to voriconazole was tested by two microdilution techniques: the National Committee for Clinical Laboratory Standards reference method M38-A and a colorimetric method, Sensititre YeastOne. The study tested a total of 244 isolates: 223 Aspergillus (136 Aspergillus fumigatus, 37 A. niger, 26 A. terreus, 16 A. flavus, 7 A. nidulans, and 1 A. ustus), 14 Fusarium (8 Fusarium moniliformis, and 6 F. oxysporum), 6 Scedosporium apiospermum, and 1 Rhizomucor pusillus strain and four control strains (Candida parapsilosis ATCC 22019, C. krusei ATCC 6258, A. fumigatus ATCC 204305, and A. flavus ATCC 204304). For all tested species except one F. moniliforme strain and R. pusillus, the MIC, the MIC at which 50% of the isolates are inhibited (MIC(50)), and MIC(90) ranges of Collapse

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MESH Headings

• Antifungal Agents/pharmacology
• Fungi/classification
• Fungi/drug effects
• Humans
• Microbial Sensitivity Tests/methods
• Microbial Sensitivity Tests/standards
• Pyrimidines/pharmacology
• Quality Control
• Reference Standards
• Triazoles/pharmacology
• Voriconazole

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Affiliation(s)

Maria José Linares Departamento de Microbiología, Facultad de Medicina, University of Córdoba, Spain
Guadalupe Charriel
Francisco Solís
Fernando Rodriguez
Ana Ibarra
M Casal

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