[Show abstract][Hide abstract] ABSTRACT: To evaluate the association between oral candidiasis and tuberculosis (TB) in human immunodeficiency virus (HIV) infected individuals in sub-Saharan Africa, and to investigate oral candidiasis as a potential tool for TB case finding.
[Show abstract][Hide abstract] ABSTRACT: Approval of topical onychomycosis drugs by regulatory agencies may be negatively impacted by overly stringent definition of complete cure, which includes nail clearing plus mycological cure.
In this position paper, we discuss interpretation of mycological outcome and clinical trial length. Methods We reviewed data from 7 international onychomycosis trials that enrolled subjects with positive KOH and dermatophyte-positive culture at screening followed by 48 weeks of treatment. Further, we examined 94 KOH positive/culture negative Week 52 follow-up samples for morphological hyphal damage.
From 3,054 samples collected at Week 52 follow-up visits, 2,360 were culture-negative. However, a significant percentage (78.7%) of these subungual samples (n=1,857) remained KOH positive. From the subset of follow-up samples examined for morphological changes, we identified hyphal breakage or distortion in 56 direct smears (60%), which may indicate non-viability.
Reassessment of the definition of onychomycosis cure is critical. For clinical trials of topical agents, length of treatment should be re-examined. Further, in our experience, a high rate of subungual debris samples remained direct smear-positive while converting to negative culture. Evidence of morphological hyphal damage suggests that late-visit microscopic results may be false-positives. Therefore, the absence of clinical signs following an adequate wash out period, coupled with a negative culture, with or without negative microscopy, should be considered the definition of onychomycosis cure. This article is protected by copyright. All rights reserved.
British Journal of Dermatology 08/2013; · 3.76 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background.The incidence of superficial dermatophytoses is high in developed countries and there remains a need for effective topical antifungals. In this study, we evaluated the in vitro antifungal activity of naftifine hydrochloride, the active ingredient in naftifine hydrochloride cream and gel 1% and 2%, against dermatophytes.Methods.MIC and MFC determinations of naftifine hydrochloride were made against 350 clinical strains, including Trichophyton rubrum, T. mentagrophytes, T. tonsurans, Epidermophyton floccosum, and Microsporum canis, using CLSI methodology. Subsets from this test panel were subsequently tested in a time kill assay at 0.125, 0.25, 0.5, and 1 times the MFC for each isolate. CFU counts were performed over a period of 48 hrs incubation. Additionally, in order to determine the potential for resistance development, six strains were subjected to fifteen serial passages in concentrations higher than the MIC for each strain. MICs were performed following each passage.Results.The MIC range against the dermatophyte isolates tested was 0.015 - 1.0 μg/mL, with naftifine hydrochloride being cidal against 85% of the Trichophyton species. The time kill assay showed dose-dependent activity, with the greatest reduction in CFU corresponding to the highest drug concentration. There was no increase in MIC for any strains following repeated exposure to naftifine hydrochloride.Conclusion.Naftifine hydrochloride demonstrated potent activity against all dermatophytes tested and demonstrated no potential for the development of resistance within this test panel. Thus, future clinical studies of naftifine hydrochloride against dermatophytes may be warranted for the treatment of superficial dermatophytoses.
Antimicrobial Agents and Chemotherapy 07/2013; · 4.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Azoles are among the most successful classes of antifungals. They act by inhibiting α-14 lanosterol demethylase in the ergosterol biosynthesis pathway. Oropharyngeal candidiasis (OPC) occurs in about 90% of HIV infected individuals, and 4-5% are refractory to current therapies, including azoles, due to the formation of resistant biofilms produced in the course of OPC. We reasoned that compounds affecting a different target may potentiate azoles to produce increased killing and an anti-biofilm therapeutic. 2-adamantanamine (AC17) was identified in a screen for compounds potentiating the action of miconazole against biofilms of Candida albicans. AC17, a close structural analog to the antiviral amantadine, did not affect the viability of C. albicans, but caused the normally fungistatic azoles to become fungicidal. Transcriptome analysis of cells treated with AC17 revealed that the ergosterol and filamentation pathways were affected. Indeed, cells exposed to AC17 had decreased ergosterol content and were unable to invade agar. In vivo, the combination of AC17 and fluconazole produced significant reduction in fungal tissue burden in a guinea pig model of cutaneous candidiasis, while each treatment alone did not have a significant effect. The combination of fluconazole and AC17 also showed improved efficacy (P-value of 0.018) compared to fluconazole alone when fungal lesions were evaluated. AC17 is a promising lead in the search for more effective antifungal therapeutics.
Antimicrobial Agents and Chemotherapy 05/2013; · 4.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objectives Dermatophytes, belonging to genera including Trichophyton, Epidermophyton, and Microsporum, are the causative agents of superficial fungal infections, prevalences of which are estimated to be as high as 25% in the worldwide population. This study evaluated the activity of topical formulations of NVC-422 (sodium 2-[dichloroamino]-2-methylpropane-1-sulfonate), the lead compound in a new class of antimicrobials that consist of broad-spectrum, fast-acting, nonantibiotic antimicrobial molecules based on the endogenously produced N-chlorotaurines. Methods The antifungal efficacy of NVC-422 was investigated using a guinea pig model of infection with Trichophyton mentagrophytes. Infected guinea pigs were randomly assigned to four treatment and two control groups. The efficacy of the treatments was assessed clinically and mycologically at 72 hours after the final topical dose. Results The test compound 2% NVC-422 in 1% Noveon Gel demonstrated the highest level of clinical efficacy. Outcomes of treatment with all other test compounds differed significantly from outcomes in the untreated control group (P = 0.003, P = 0.029, P = 0.012, and P < 0.0001, respectively). Fungal elements were detectable in skin sections from untreated guinea pigs but not in skin sections obtained from any of the treatment groups. Conclusions Evaluation of the efficacy of NVC-422 in the treatment of dermatophytosis using an experimental guinea pig model showed that this compound possesses potent antifungal efficacy as measured by mycological and clinical endpoints. The highest degree of clinical and mycological efficacy was demonstrated by 2% NVC-422 in 1% Noveon Gel. These data show that NVC-422 has potent antifungal activity in vivo. Clinical evaluation of NVC-422 in the treatment of superficial infections caused by dermatophytes, including onychomycosis, is warranted.
International journal of dermatology 05/2013; 52(5):567-571. · 1.18 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Microbial infections of the cornea frequently cause painful, blinding and debilitating disease that is often difficult to treat and may require corneal transplantation. In addition, sterile corneal infiltrates that are associated with contact lens wear cause pain, visual impairment and photophobia. In this article, we review the role of Toll-Like Receptors (TLR) in bacterial keratitis and sterile corneal infiltrates, and describe the role of MD-2 regulation in LPS responsiveness by corneal epithelial cells. We conclude that both live bacteria and bacterial products activate Toll-Like Receptors in the cornea, which leads to chemokine production and neutrophil recruitment to the corneal stroma. While neutrophils are essential for bacterial killing, they also cause tissue damage that results in loss of corneal clarity. These disparate outcomes, therefore, represent a spectrum of disease severity based on this pathway, and further indicate that targeting the TLR pathway is a feasible approach to treating inflammation caused by live bacteria and microbial products. Further, as the P. aeruginosa type III secretion system (T3SS) also plays a critical role in disease pathogenesis by inducing neutrophil apoptosis and facilitating bacterial growth in the cornea, T3SS exotoxins are additional targets for therapy for P. aeruginosa keratitis.
International Reviews Of Immunology 01/2013; 32(1):4-18. · 5.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Introduction: Current topical treatments for onychomycosis are unsatisfactory. New topical agents that offer efficacy without the potential adverse effects of oral antifungal therapy would benefit patients with this condition and encourage a greater treatment rate. Areas covered: Currently available topical therapies are reviewed, and new approaches for enhancing delivery of the established antifungal terbinafine through the nail are summarized. We focus on the use of ultra-deformable lipid vesicles to facilitate delivery of terbinafine to the nail and surrounding tissue. TDT 067 (terbinafine in Transfersome®) is the only such therapy in development for onychomycosis, and we review published preclinical and clinical studies on this formulation. Expert opinion: TDT 067 offers the use of new technology to deliver an established antifungal, terbinafine. Preclinical data suggest that the Transfersome® accelerates entry of terbinafine released from TDT 067 into fungi and potentiates its antifungal effects, resulting in enhanced activity, compared with conventional terbinafine. This translated into high rates of mycological cure and evidence of clinical effect in a study of TDT 067 administered twice daily for 12 weeks in patients with onychomycosis. An ongoing Phase-III trial involving more than 700 patients treated for 48 weeks is investigating the efficacy and safety of TDT 067.
[Show abstract][Hide abstract] ABSTRACT: A commercially prepared dried colorimetric microdilution panel (Sensititre Yeast One, TREK Diagnostic Systems, Cleveland, OH, USA) was compared in 3 different laboratories with the Clinical and Laboratory Standards Institute (CLSI) reference microdilution method by testing 2 quality control strains, 25 reproducibility strains, and 404 isolates of Candida spp. against anidulafungin, caspofungin, and micafungin. Reference CLSI BMD MIC end points and YeastOne colorimetric end points were read after 24 h of incubation. Excellent (100%) essential agreement (within 2 dilutions) between the reference and colorimetric MICs was observed. Categorical agreement (CA) between the 2 methods was assessed using the new species-specific clinical breakpoints (CBPs): susceptible (S), ≤0.25 μg/mL; intermediate (I), 0.5 μg/mL; and resistant (R), ≥1 μg/mL, for C. albicans, C. tropicalis, and C. krusei, and ≤2 μg/mL (S), 4 μg/mL (I), and ≥8 μg/mL (R) for C. parapsilosis and all 3 echinocandins. The new CBPs for anidulafungin and caspofungin and C. glabrata are ≤0.12 μg/mL (S), 0.25 μg/mL (I), and ≥0.5 μg/mL (R), whereas those for micafungin are ≤0.06 μg/mL (S), 0.12 μg/mL (I), and ≥0.25 μg/mL (R). Due to the lack of CBPs for any of the echinocandins and C. lusitaniae, the epidemiological cutoff values (ECVs) were used for this species to categorize the isolates as wild-type (WT; MIC ≤ECV) and non-WT (MIC >ECV), respectively, for anidulafungin (≤2 μg/mL/>2 μg/mL), caspofungin (≤1 μg/mL/>1 μg/mL), and micafungin (≤0.5 μg/mL/>0.5 μg/mL). CA ranged from 93.6% (caspofungin) to 99.6% (micafungin) with less than 1% very major or major errors. The YeastOne colorimetric method remains comparable to the CLSI BMD reference method for testing the susceptibility of Candida spp. to the echinocandins when using the new (lower) CBPs and ECVs. Further study using defined fks mutant strains of Candida is warranted.
[Show abstract][Hide abstract] ABSTRACT: Mycograb C28Y is a recombinant human antibody fragment thought to target HSP-90 and potentiate amphotericin B (AMB). Absence of in vivo efficacy led us to reevaluate its in vitro activity. Interactions between AMB and Mycograb were investigated using a checkerboard design. Addition of Mycograb or various unrelated proteins, including human serum, resulted in similar decreases in the MIC of AMB. Potentiation of AMB by Mycograb appears to be a nonspecific protein effect.
Antimicrobial Agents and Chemotherapy 04/2012; 56(7):3963-4. · 4.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Clinical breakpoints (CBPs) and epidemiological cutoff values (ECVs) have been established for several Candida spp. and the newer triazoles and echinocandins but are not yet available for older antifungal agents, such as amphotericin B, flucytosine, or itraconazole. We determined species-specific ECVs for amphotericin B (AMB), flucytosine (FC) and itraconazole (ITR) for eight Candida spp. (30,221 strains) using isolates from 16 different laboratories in Brazil, Canada, Europe, and the United States, all tested by the CLSI reference microdilution method. The calculated 24- and 48-h ECVs expressed in μg/ml (and the percentages of isolates that had MICs less than or equal to the ECV) for AMB, FC, and ITR, respectively, were 2 (99.8)/2 (99.2), 0.5 (94.2)/1 (91.4), and 0.12 (95.0)/0.12 (92.9) for C. albicans; 2 (99.6)/2 (98.7), 0.5 (98.0)/0.5 (97.5), and 2 (95.2)/4 (93.5) for C. glabrata; 2 (99.7)/2 (97.3), 0.5 (98.7)/0.5 (97.8), and 05. (99.7)/0.5 (98.5) for C. parapsilosis; 2 (99.8)/2 (99.2), 0.5 (93.0)/1 (90.5), and 0.5 (97.8)/0.5 (93.9) for C. tropicalis; 2 (99.3)/4 (100.0), 32 (99.4)/32 (99.3), and 1 (99.0)/2 (100.0) for C. krusei; 2 (100.0)/4 (100.0), 0.5 (95.3)/1 (92.9), and 0.5 (95.8)/0.5 (98.1) for C. lusitaniae; -/2 (100.0), 0.5 (98.8)/0.5 (97.7), and 0.25 (97.6)/0.25 (96.9) for C. dubliniensis; and 2 (100.0)/2 (100.0), 1 (92.7)/-, and 1 (100.0)/2 (100.0) for C. guilliermondii. In the absence of species-specific CBP values, these wild-type (WT) MIC distributions and ECVs will be useful for monitoring the emergence of reduced susceptibility to these well-established antifungal agents.
Journal of clinical microbiology 03/2012; 50(6):2040-6. · 4.16 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: TDT 067 is a novel, carrier-based dosage form of terbinafine in Transfersome (1.5%) formulated for topical delivery of terbinafine to the nail, nail bed, and surrounding tissue. We examined the effects of TDT 067 and conventional terbinafine on the morphology of dermatophytes. Trichophyton rubrum hyphae were exposed to TDT 067 or terbinafine (15 mg/ml) and examined under white light, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Subungual debris from patients treated with TDT 067 in a clinical trial was also examined. Exposure of T. rubrum hyphae to TDT 067 led to rapid and extensive ultrastructural changes. Hyphal distortion was evident as early as 4 h after exposure to TDT 067. After 24 h, there was complete disruption of hyphal structure with few intact hyphae remaining. Exposure to terbinafine resulted in morphological alterations similar to those seen with TDT 067; however, the effects of TDT 067 were more extensive, whereas a portion of hyphae remained intact after 24 h of exposure to terbinafine. Lipid droplets were observed under TEM following 30 min of exposure to TDT 067, which after 24 h had filled the intracellular space. These effects were confirmed in vivo in subungual debris from patients with onychomycosis who received topical treatment with TDT 067. The Transfersome in TDT 067 may potentiate the action of terbinafine by delivering terbinafine more effectively to its site of action inside the fungus. Our in vivo data confirm that TDT 067 can enter fungus in the nail bed of patients with onychomycosis and exert its antifungal effects.
Antimicrobial Agents and Chemotherapy 02/2012; 56(5):2530-4. · 4.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Rhodococcus is an emerging cause of opportunistic infection in immunocompromised patients, most commonly causing cavitary pneumonia. It has rarely been reported as a cause of isolated bacteremia. However, the relationship between bacteremia and central venous catheter is unknown. Between 2002 and 2010, the characteristics and outcomes of seventeen cancer patients with Rhodococcus bacteremia and indwelling central venous catheters were evaluated. Rhodococcus bacteremias were for the most part (94%) central line-associated bloodstream infection (CLABSI). Most of the bacteremia isolates were Rhodococcus equi (82%). Rhodococcus isolates formed heavy microbial biofilm on the surface of polyurethane catheters, which was reduced completely or partially by antimicrobial lock solution. All CLABSI patients had successful response to catheter removal and antimicrobial therapy. Rhodococcus species should be added to the list of biofilm forming organisms in immunocompromised hosts and most of the Rhodococcus bacteremias in cancer patients are central line associated.
PLoS ONE 01/2012; 7(3):e32945. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background Terbinafine nail solution (TNS) was developed for the treatment of onychomycosis. Objective To assess the efficacy of TNS vs. vehicle and amorolfine 5% nail lacquer. Methods Subjects with mild-to-moderate toe onychomycosis (25% to ≤75% nail-involvement, matrix uninvolved) were randomized to receive either TNS or vehicle in two double-blind studies, and to TNS or amorolfine in an active-controlled, open-label study. Primary endpoint was complete cure (no residual clinical involvement and negative mycology) at week 52. Secondary endpoints were mycological cure (negative mycology defined as negative KOH microscopy and negative culture) and clinical effectiveness (≤10% residual-involvement and negative mycology) at week 52. Results Complete cure was not different between TNS vs. vehicle and amorolfine. Mycological cure was higher with TNS vs. vehicle, as was clinical effectiveness with TNS vs. vehicle, and TNS and amorolfine were not different for secondary efficacy endpoints. Patients achieving mycological cure had a better clinical outcome, and efficacy was improved in subjects with milder disease. Post hoc analysis suggests that nail thickness is an important prognostic factor. Moreover, mycological cure may require 6 months of treatment regimen while complete cure and clinical effectiveness may be achievable only after 10 months. A simulation study suggests that longer treatment duration would have resulted in higher complete cure with TNS vs. vehicle. Study treatments were well-tolerated. Conclusion Primary efficacy objectives were not met in the studies reported herein. Possible reasons for failure to achieve significant outcomes include insufficient length of treatment; stringency of primary endpoint and severity of nail involvement of study population.
Journal of the European Academy of Dermatology and Venereology 12/2011; · 2.69 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cryptococcus neoformans strains resistant to azoles due to mutations causing alterations in the ERG11 gene, encoding lanosterol 14α-demethylase, have rarely been reported. In this study, we have characterized a C. neoformans serotype A strain that is resistant to high concentrations of fluconazole (FLC). This strain, which was isolated from an FLC-treated patient, contained five missense mutations in the ERG11 gene compared to the sequence of reference strain H99. Molecular manipulations of the ERG11 gene coupled with susceptibility to triazole revealed that a single missense mutation resulting in the replacement of tyrosine by phenylalanine at amino acid 145 was sufficient to cause the high FLC resistance of the strain. Importantly, this newly identified point mutation in the ERG11 gene of C. neoformans afforded resistance to voriconazole (VRC) but increased susceptibility to itraconazole (ITC) and posaconazole (PSC), which are structurally similar to each other but distinct from FLC/VRC. The in vitro susceptibility/resistance of the strains with or without the missense mutation was reflected in the therapeutic efficacy of FLC versus ITC in the animals infected with the strains. This study shows the importance of the Y145F alteration of Erg11 in C. neoformans for manifestation of differential susceptibility toward different triazoles. It underscores the necessity of in vitro susceptibility testing for each FLC-resistant C. neoformans clinical isolate against different groups of azoles in order to assist patient management.
Antimicrobial Agents and Chemotherapy 12/2011; 56(3):1162-9. · 4.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The discovery of echinocandins, and their development and approval, was hailed as a significant addition to our antifungal armamentarium, previously predominated by polyenes and azoles. To date, three echinocandins (anidulafungin, caspofungin, and micafungin) have been approved by the U.S. Food and Drug Administration for the treatment of fungal infections. Since all three echinocandins target the fungal cell wall and share a similar structural chemical backbone, they are perceived to be identical. However, a scientific literature review shows distinct differences among the echinocandins in terms of in vitro activity, fungicidal activity, post-antifungal effect, paradoxical effect, and activity on biofilms. More investigation is warranted to determine if the observed differences among the echinocandins can translate to clinical advantages.
[Show abstract][Hide abstract] ABSTRACT: Candida albicans-associated bloodstream infections are linked to the ability of this yeast to form biofilms. In this study, we used lipidomics to compare the lipid profiles of C. albicans biofilms and planktonic cells, in early and mature developmental phases. Our results showed that significant differences exist in lipid composition in both developmental phases. Biofilms contained higher levels of phospholipid and sphingolipids than planktonic cells (nmol per g biomass, P<0.05 for all comparisons). In the early phase, levels of lipid in most classes were significantly higher in biofilms compared to planktonic cells (P≤0.05). The ratio of phosphatidylcholine to phosphatidylethanolamine was lower in biofilms compared to planktonic cells in both early (1.17 vs 2.52, P≤0.001) and late (2.34 vs 3.81, P≤0.001) developmental phases. The unsaturation index of phospholipids decreased with time, with this effect being particularly strong for biofilms. Inhibition of the biosynthetic pathway for sphingolipid [mannosyl diinositolphosphoryl ceramide, M(IP)₂C] by myriocin or aureobasidin A, and disruption of the gene encoding inositolphosphotransferase (Ipt1p), abrogated the ability of C. albicans to form biofilms. The differences in lipid profiles between biofilms and planktonic Candida cells may have important implications for the biology and antifungal resistance of biofilms.
[Show abstract][Hide abstract] ABSTRACT: The triple combination trimethoprim, EDTA, and ethanol (B-Lock), is an antimicrobial lock solution for use in indwelling intravascular catheters to prevent and treat catheter-associated infections. B-Lock demonstrated MICs of ≤0.05% (percentage of solution) against Candida spp. (n = 125) and 0.003% to 25% against bacterial strains (n = 175). B-Lock was also fungicidal against the majority of the Candida strains at 6% to 25%. B-Lock demonstrates potential value for the prevention and treatment of catheter-associated infections.
Antimicrobial Agents and Chemotherapy 09/2011; 55(9):4430-1. · 4.57 Impact Factor