Biomaterials surfaces capable of resisting fungal attachment and biofilm formation.

Microbial attachment onto biomedical devices and implants leads to biofilm formation and infection; such biofilms can be bacterial, fungal, or mixed. In the past 15 years, there has been an increasing research effort into antimicrobial surfaces but the great majority of these publications present research on bacteria, with some reports also testing resistance to fungi. Very few studies have focused exclusively on antifungal surfaces. However, with increasing recognition of the importance of fungal infections to human health, particularly related to infections at biomaterials, it would seem that the interest in antifungal surfaces is disproportionately low. In studies of both bacteria and fungi, fungi tend to be the minor focus with hypothesized antibacterial mechanisms of action often generalized to also explain the antifungal effect. Yet bacteria and fungi represent two Distinct biological Domains and possess substantially different cellular physiology and structure. Thus it is questionable whether these generalizations are valid. Here we review the scientific literature focusing on surface coatings prepared with antifungal agents covalently attached to the biomaterial surface. We present a critical analysis of generalizations and their evidence. This review should be of interest to researchers of "antimicrobial" surfaces by addressing specific issues that are key to designing and understanding antifungal biomaterials surfaces and their putative mechanisms of action.

Pathogenicity of non-albicans yeasts in the vagina.

OBJECTIVE: It is hypothesized that vaginal non-albicans yeasts (NAYs) do not require treatment. The objective was to determine whether women (presenting with a range of vulvovaginal complaints) found to be harboring NAY, which is left untreated (no antifungals), have similar clinical outcomes to women with comparable presentations but who do not harbor NAY. DESIGN: This is a case-control study design comparing patient outcomes between women with untreated non-albicans Candida on vaginal swab cultures and those who were swab culture-negative. SETTING: A Melbourne metropolitan, private gynecologic and obstetric practice. POPULATION: Women presenting with vulvovaginal symptoms or management of pregnancy, who attended the above practice between 2001 and 2006. METHODS: Fifty-two women were found to have NAY on culture of their vaginal swabs. They were prospectively studied to determine the effect of leaving the NAY untreated (no antifungals) but with appropriate attention to their other diagnoses. Seventy-eight symptomatic women with negative swab cultures were used as the comparison group, and descriptive statistics was computed to compare patient outcomes between the groups. A subanalysis was also carried out, only looking at women who presented with pruritus. MAIN OUTCOME MEASURE: Proportion of patients self-reporting improvement in symptoms. RESULTS: Of the 44 women with NAY who presented with symptoms, 86% reported experiencing improvement. Approximately 77% of the women in the comparative group reported improvement. CONCLUSIONS: Non-albicans yeasts found on culture of a vaginal swab can probably be ignored. The clinician's efforts should be concentrated on making a correct diagnosis without assuming that NAY are pathogenic.

In vitro antifungal activities of bis(alkylpyridinium)alkane compounds against pathogenic yeasts and molds.

Ten bis(alkylpyridinium)alkane compounds were tested for antifungal activity against 19 species (26 isolates) of yeasts and molds. We then determined the MICs and minimum fungicidal concentrations (MFCs) of four of the most active compounds (compounds 1, 4, 5, and 8) against 80 Candida and 20 cryptococcal isolates, in comparison with the MICs of amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, and caspofungin, using Clinical Laboratory and Standards Institutes broth microdulition M27-A3 (yeasts) or M38-A2 (filamentous fungi) susceptibility protocols. The compounds were more potent against Candida and Cryptococcus spp. (MIC range, 0.74 to 27.9 microg/ml) than molds (0.74 to 59.7 microg/ml). MICs against Exophiala were 0.37 to 5.9 microg/ml and as low as 1.48 microg/ml for Scedosporium but >or=25 microg/ml for zygomycetes, Aspergillus, and Fusarium spp. Compounds 1, 4, 5, and 8 exhibited good fungicidal activity against Candida and Cryptococcus, except for Candida parapsilosis (MICs of >44 mug/ml). Geometric mean (GM) MICs were similar to those of amphotericin B and lower than or comparable to fluconazole GM MICs but 10- to 100-fold greater than those for the other azoles. GM MICs against Candida glabrata were <1 microg/ml, significantly lower than fluconazole GM MICs (P<0.001) and similar to those of itraconazole, posaconazole, and voriconazole (GM MIC range of 0.4 to 1.23 microg/ml). The GM MIC of compound 4 against Candida guilliermondii was lower than that of fluconazole (1.69 microg/ml versus 7.48 microg/ml; P=0.012). MICs against Cryptococcus neoformans and Cryptococcus gattii were similar to those of fluconazole. The GM MIC of compound 4 was significantly higher for C. neoformans (3.83 mug/ml versus 1.81 microg/ml for C. gattii; P=0.015). This study has identified clinically relevant in vitro antifungal activities of novel bisalkypyridinium alkane compounds.

Candidaemia in adult cancer patients: risks for fluconazole-resistant isolates and death.

BACKGROUND: Candidaemia in cancer patients is associated with increasing fluconazole resistance. Models for predicting such isolates and their clinical impact are required. METHODS: Clinical, treatment and outcome data from a population-based candidaemia survey (2001-2004) were collected at 5 and 30 days after diagnosis. Speciation and antifungal susceptibility testing was performed. RESULTS: There were 138 candidaemia episodes (33% Candida albicans) in adults with haematological malignancies and 150 (51% C. albicans) in adults with solid organ malignancies. Thirty-nine isolates had fluconazole MICs of >or=64 mg/L and 40 had MICs of 16-32 mg/L (predominantly Candida glabrata and Candida krusei). By multivariate analysis, triazole therapy, gastrointestinal tract (GIT) surgery in the 30 days before candidaemia and age >65 years were predictive of fluconazole-resistant candidaemia. Thirty day crude mortality was 40% in haematology patients and 45% in oncology patients. Fluconazole-resistant isolates were associated with increased risk of mortality by univariate (P = 0.04) and Kaplan-Meier survival analyses. By Cox proportional hazards modelling, the strongest predictors of mortality at onset of candidaemia were invasive ventilation, elevated creatinine, intensive care unit (ICU) admission and receipt of systemic triazoles or corticosteroids in the previous 30 days. Removal of a central venous access device (CVAD) at or within 5 days of onset was associated with decreased mortality. CONCLUSIONS: Risk factors for fluconazole-resistant candidaemia in adults with cancer include fluconazole/triazole exposure and GIT surgery. ICU admission, invasive ventilation, renal impairment, age >65 years and prior exposure to corticosteroids and triazoles are risk factors for death. CVAD removal reduced mortality. These findings should be integrated into surveillance and treatment algorithms.

Synthesis, antifungal, haemolytic and cytotoxic activities of a series of bis(alkylpyridinium)alkanes.

A series of bis(alkylpyridinium)alkanes with a twelve carbon spacer between the positive charges was synthesised and their antifungal activity has been investigated. Compounds with 2-pentyl, 4-pentyl, 4-hexyl, 4-octyl, 4-propylbenzene, 3,4-dipentyl, 4-(5'-nonyl) and 3-methyl,4-pentyl head groups were the most potent antifungal agents with MICs in the range of 1.4-2.7 microM against reference strains of both Cryptococcus neoformans and Candida albicans.

Cutaneous zygomycosis caused by Saksenaea vasiformis following water-related wound in a 24-year-old immunocompetent woman.

We describe a case of cutaneous zygomycosis caused by Saksenaea vasiformis in an immunocompetent 24-year-old woman. Diagnosis was based on histological and microbiological examination. The patient made a complete recovery with surgical debridement and antifungal therapy (liposomal amphotericin and posaconazole).

Scedosporium prolificans osteomyelitis in an immunocompetent child treated with a novel agent, hexadecylphospocholine (miltefosine), in combination with terbinafine and voriconazole: a case report.

We describe an 8-year-old girl who sustained multiple compound fractures in an accident involving agricultural equipment. She developed Scedosporium prolificans osteomyelitis of the pelvis, septic arthritis of the hip, and myositis of adjacent muscles. The infection progressed, despite extensive surgical debridement and joint washouts with 0.2% polyhexamethylene biguanide; antifungal therapy with caspofungin, terbinafine, and voriconazole; and adjunctive therapy with interferon-gamma. Gradual resolution was achieved after the addition of a novel agent, hexadecylphospocholine (miltefosine), and the continuation of terbinafine and voriconazole. This is the first report of the use of miltefosine as an antifungal agent in the management of severe infection with S. prolificans.

Hexadecylphosphocholine (miltefosine) has broad-spectrum fungicidal activity and is efficacious in a mouse model of cryptococcosis.

The alkyl phosphocholine drug miltefosine is structurally similar to natural substrates of the fungal virulence determinant phospholipase B1 (PLB1), which is a potential drug target. We determined the MICs of miltefosine against key fungal pathogens, correlated antifungal activity with inhibition of the PLB1 activities (PLB, lysophospholipase [LPL], and lysophospholipase-transacylase [LPTA]), and investigated its efficacy in a mouse model of disseminated cryptococcosis. Miltefosine inhibited secreted cryptococcal LPTA activity by 35% at the subhemolytic concentration of 25 microM (10.2 microg/ml) and was inactive against mammalian pancreatic phospholipase A2 (PLA2). At 250 microM, cytosolic PLB, LPL, and LPTA activities were inhibited by 25%, 51%, and 77%, respectively. The MICs at which 90% of isolates were inhibited (MIC90s) against Candida albicans, Candida glabrata, Candida krusei, Cryptococcus neoformans, Cryptococcus gattii, Aspergillus fumigatus, Fusarium solani, Scedosporium prolificans, and Scedosporium apiospermum were 2 to 4 microg/ml. The MICs of miltefosine against Candida tropicalis (n = 8) were 2 to 4 microg/ml, those against Aspergillus terreus and Candida parapsilosis were 8 microg/ml (MIC90), and those against Aspergillus flavus (n = 8) were 2 to 16 microg/ml. Miltefosine was fungicidal for C. neoformans, with rates of killing of 2 log units within 4 h at 7.0 microM (2.8 microg/ml). Miltefosine given orally to mice on days 1 to 5 after intravenous infection with C. neoformans delayed the development of illness and mortality and significantly reduced the brain cryptococcal burden. We conclude that miltefosine has broad-spectrum antifungal activity and is active in vivo in a mouse model of disseminated cryptococcosis. The relatively small inhibitory effect on PLB1 enzyme activities at concentrations exceeding the MIC by 2 to 20 times suggests that PLB1 inhibition is not the only mechanism of the antifungal effect.

Use of terbinafine for tinea in Australian Aboriginal communities in the Top End.

Tinea of the skin and nails is a common problem in remote Aboriginal communities of the Top End of Australia. A retrospective study was performed on data collected from 104 patients from several indigenous communities. Worksheets were filled in by district medical officers and rural general practitioners, detailing the extent of the tinea. Patients were prescribed between 4 and 12 weeks of 250 mg daily oral terbinafine. Fifty-two patients were followed up, with 45 having a good response to treatment (87%) and with 22 of these patients having full clearance of tinea (42%). A prospective study with 44 subjects was performed. The extent of the tinea was documented and fungal scrapings/clippings were taken. Forty subjects were recruited and given oral terbinafine (2-12 weeks depending on skin/nail involvement) or topical terbinafine if oral treatment was contraindicated. Twenty-five of the 40 (63%) subjects were reviewed. Twenty-three (92%) subjects that were followed up improved clinically, with 8/25 (32%) clearing completely. Twenty (80%) of followed-up patients complied fully with treatment. Terbinafine was found to be a well-tolerated and effective treatment of tinea of the skin and nails.

Unique biological properties and molecular mechanism of 5,6-bridged quinolones.

We have characterized an early series of 5,6-bridged dioxinoquinolones which behaved strikingly different from typical quinolones. The 5,6-bridged dioxinoquinolones inhibited Escherichia coli DNA gyrase supercoiling activity but, unlike typical quinolones, failed to stimulate gyrase-dependent cleavable complex formation. Analogous unsubstituted compounds stimulated cleavable complex formation but were considerably less potent than the corresponding 5,6-bridged compounds. Consistent with a previous report (M. Antoine et al., Chim. Ther. 7:434-443, 1972) and contrary to established quinolone SAR trends, a compound with an N-1 methyl substitution (PGE-8367769) was more potent than its analog with an N-1 ethyl substitution (PGE-6596491). PGE-8367769 was shown to antagonize ciprofloxacin-mediated cleavable complex formation in a dose-dependent manner, suggesting an interaction with the gyrase-DNA complex that overlaps that of ciprofloxacin. Resistance to PGE-8367769 in E. coli was found to arise through missense mutations in gyrA, implicating DNA gyrase as the primary antibacterial target. Notably, only 1 of 15 distinct mutations selected on PGE-8367769 (D87G) has previously been implicated in quinolone resistance in E. coli. The remaining 14 mutations (E16V, G31V, R38L, G40A, Y50D, V70A, A84V, I89L, M135T, G173S, T180I, F217C, P218T, and F513C) have not been previously reported, and most were located outside of the traditional quinolone resistance-determining region. These novel GyrA mutations decreased sensitivity to 5,6-bridged dioxinoquinolones by four- to eightfold, whereas they did not confer resistance to other quinolones such as ciprofloxacin, clinafloxacin, or nalidixic acid. These results demonstrate that the 5,6-bridged quinolones act via a mechanism that is related to but qualitatively different from that of typical quinolones.