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Spivack S, Gold JAW, Lockhart SR, Anand P, Quilter LAS, Smith DJ, Bowen B, Gould JM, Eltokhy A, Gamal A, Retuerto M, McCormick TS, Ghannoum MA. Potential Sexual Transmission of Antifungal-Resistant Trichophyton indotineae. Emerg Infect Dis 2024; 30:807-809. [PMID: 38437706 PMCID: PMC10977831 DOI: 10.3201/eid3004.240115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2024] Open
Abstract
We describe a case of tinea genitalis in an immunocompetent woman in Pennsylvania, USA. Infection was caused by Trichophyton indotineae potentially acquired through sexual contact. The fungus was resistant to terbinafine (first-line antifungal) but improved with itraconazole. Clinicians should be aware of T. indotineae as a potential cause of antifungal-resistant genital lesions.
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Lipner SR, Vlahovic T, Ghannoum MA, Elewski B, Joseph WS. Dermatophytomas in Onychomycosis: A Scoping Review of Prevalence, Diagnosis, and Treatment. J Am Podiatr Med Assoc 2024; 114:22-161. [PMID: 38753536 DOI: 10.7547/22-161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
BACKGROUND Dermatophytoma, also described as a longitudinal streak/spike, is a form of onychomycosis that presents as yellow/white streaks or patches in the subungual space, with dense fungal masses encased in biofilm. This scoping review of the literature was conducted to address a general lack of information about the epidemiology, pathophysiology, and treatment of dermatophytomas in onychomycosis. METHODS A search was performed in the PubMed and Embase databases for the terms "longitudinal spike" or "dermatophytoma." Outcomes of interest were definition, prevalence, methods used for diagnosis, treatments, and treatment efficacy. Inclusion and exclusion of search results required agreement between two independent reviewers. RESULTS Of a total of 51 records, 37 were included. Two reports provided the first unique definitions/clinical features of dermatophytomas. Overall, many descriptions were found, but one conclusive definition was lacking. Prevalence data were limited and inconsistent. The most frequently mentioned diagnostic techniques were clinical assessment, potassium hydroxide/microscopy, and fungal culture/mycology. Oral terbinafine and topical efinaconazole 10% were the most frequently mentioned treatments, followed by topical luliconazole 5% and other oral treatments (itraconazole, fluconazole, fosravuconazole). In studies with five or more patients without nail excision, cure rates were highest with efinaconazole 10%, which ranged from 41% to 100% depending on the clinical and/or mycologic assessment evaluated. Other drugs with greater than or equal to 50% cure rates were topical luliconazole 5% (50%), oral fosravuconazole (57%), and oral terbinafine (67%). In studies that combined oral terbinafine treatment with nail excision using surgical or chemical (40% urea) methods, cure rates ranged from 50% to 100%. CONCLUSIONS There is little published information regarding dermatophytomas in onychomycosis. More clinical research and physician education are needed. Although dermatophytomas have historically been considered difficult to treat, the efficacy data gathered in this scoping review have demonstrated that newer topical treatments are effective, as are oral antifungals in combination with chemical or surgical methods.
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Palm KM, Abrams MK, Sears SB, Wherley SD, Alfahmy AM, Kamumbu SA, Chakraborty NN, Mahajan ST, El-Nashar SA, Henderson JW, Hijaz AK, Mangel JM, Pollard RR, Al-Shakhshir H, Retuerto MA, Steller KM, Elshaer M, Ghannoum MA, Sheyn D. The Response of the Urinary Microbiome to Botox. Int Urogynecol J 2024; 35:237-251. [PMID: 38165444 DOI: 10.1007/s00192-023-05703-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 11/15/2023] [Indexed: 01/03/2024]
Abstract
INTRODUCTION AND HYPOTHESIS Our objective was to evaluate if botox alters the urinary microbiome of patients with overactive bladder and whether this alteration is predictive of treatment response. METHODS This multicenter prospective cohort study included 18-89-year-old patients undergoing treatment for overactive bladder with 100 units of botox. Urine samples were collected by straight catheterization on the day of the procedure (S1) and again 4 weeks later (S2). Participants completed the Patient Global Impression of Improvement form at their second visit for dichotomization into responders and nonresponders. The microbiome was sequenced using 16s rRNA sequencing. Wilcoxon signed rank and Wilcoxon rank sum were used to compare the microbiome, whereas chi-square, Wilcoxon rank sum, and the independent t-test were utilized for clinical data. RESULTS Sixty-eight participants were included in the analysis. The mean relative abundance and prevalence of Beauveria bassiana, Xerocomus chrysenteron, Crinipellis zonata, and Micrococcus luteus were all found to increase between S1 and S2 in responders; whereas in nonresponders the mean relative abundance and prevalence of Pseudomonas fragi were found to decrease. The MRA and prevalence of Weissella cibaria, Acinetobacter johnsonii, and Acinetobacter schindleri were found to be greater in responders than nonresponders at the time of S1. Significant UM differences in the S1 of patients who did (n = 5) and did not go on to develop a post-treatment UTI were noted. CONCLUSIONS Longitudinal urobiome differences may exist between patients who do and do not respond to botox.
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Kruithoff C, Gamal A, McCormick TS, Ghannoum MA. Dermatophyte Infections Worldwide: Increase in Incidence and Associated Antifungal Resistance. Life (Basel) 2023; 14:1. [PMID: 38276250 PMCID: PMC10817648 DOI: 10.3390/life14010001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/15/2023] [Accepted: 12/15/2023] [Indexed: 01/27/2024] Open
Abstract
The increase in incidence of superficial fungal infections combined with the emergence of antifungal resistance represents both a global health challenge and a considerable economic burden. Recently, dermatophytes, the main culprit causing superficial fungal infections, have started to exhibit antifungal resistance. This can be observed in some of the most common species such as Trichophyton rubrum and Trichophyton mentagrophytes. Importantly, the new subspecies, known as Trichophyton indotineae, has been reported to show high resistance to terbinafine, a first-line treatment for dermatophyte infections. Compounding these issues is the realization that diagnosing the causative infectious agents requires using molecular analysis that goes beyond the conventional macroscopic and microscopic methods. These findings emphasize the importance of conducting antifungal susceptibility testing to select the appropriate antifungal necessary for successful treatment. Implementing these changes may improve clinical practices that combat resistant dermatophyte infections.
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Ha MV, McCormick TS, Salem I, Al-Shakhshir H, Ghannoum MA, Carroll BT. Skin and gut microbial associations with squamous cell carcinoma in solid organ transplant recipients. Arch Dermatol Res 2023; 315:2709-2713. [PMID: 37278910 DOI: 10.1007/s00403-023-02644-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 04/25/2023] [Accepted: 05/17/2023] [Indexed: 06/07/2023]
Abstract
Solid organ transplant recipients (SOTRs) are burdened with a significantly higher risk of squamous cell carcinoma (SCC) compared to the general population. Accumulating evidence suggests the potential influence of microbial dysbiosis on transplant outcomes. Based on these observations, we sought to identify differences in the cutaneous and gut microbiomes of SOTRs with and without a history of SCC. This case-control study collected and analyzed non-lesional skin and fecal samples of 20 SOTRs > 18 years old with either ≥ 4 diagnoses of SCC since most recent transplant (n = 10) or 0 diagnoses of SCC (n = 10). The skin and gut microbiomes were investigated with Next-Generation Sequencing, and analysis of variance (ANOVA) followed by Tukey pairwise comparison procedure was used to test for differences in taxonomic relative abundances and microbial diversity indices between the two cohorts. Analyses of the skin microbiome showed increased bacterial and reduced fungal diversity in SOTRs with a history of SCC compared to SOTRs without a history of SCC (bacterial median Shannon diversity index (SDI) = 3.636 and 3.154, p < 0.05; fungal SDI = 4.474 and 6.174, p < 0.05, respectively). Analyses of the gut microbiome showed reduced bacterial and fungal diversity in the SCC history cohort compared to the SCC history-negative cohort (bacterial SDI = 2.620 and 3.300, p < 0.05; fungal SDI = 3.490 and 3.812, p < 0.05, respectively). The results of this pilot study thus show a trend toward the bacterial and fungal communities of the gut and skin being distinct in SOTRs with a history of SCC compared to SOTRs without a history of SCC. It furthermore demonstrates the potential for microbial markers to be used in the prognostication of squamous cell carcinoma risk in solid organ transplant recipients.
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Gowen R, Gamal A, Di Martino L, McCormick TS, Ghannoum MA. Modulating the Microbiome for Crohn's Disease Treatment. Gastroenterology 2023; 164:828-840. [PMID: 36702360 PMCID: PMC10152883 DOI: 10.1053/j.gastro.2023.01.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/12/2022] [Accepted: 01/06/2023] [Indexed: 01/28/2023]
Abstract
The central role of the gut microbiota in the regulation of health and disease has been convincingly demonstrated. Polymicrobial interkingdom interactions between bacterial (the bacteriome) and fungal (the mycobiome) communities of the gut have become a prominent focus for development of potential therapeutic approaches. In addition to polymicrobial interactions, the complex gut ecosystem also mediates interactions between the host and the microbiota. These interactions are complex and bidirectional; microbiota composition can be influenced by host immune response, disease-specific therapeutics, antimicrobial drugs, and overall ecosystems. However, the gut microbiota also influences host immune response to a drug or therapy by potentially transforming the drug's structure and altering bioavailability, activity, or toxicity. This is especially true in cases where the gut microbiota has produced a biofilm. The negative ramifications of biofilm formation include alteration of gut permeability, enhanced antimicrobial resistance, and alteration of host immune response effectiveness. Natural modulation of the gut microbiota, using probiotic and prebiotic approaches, may also be used to affect the host microbiome, a type of "natural" modulation of the host microbiota composition. In this review, we discuss potential bidirectional interactions between microbes and host, and we describe the changes in gut microbiota induced by probiotic and prebiotic approaches as well as their potential clinical consequences, including biofilm formation. We outline a systematic approach to designing probiotics capable of altering the host microbiota in disease states, using Crohn's disease as a model chronic disease. Understanding how the effective changes in the microbiome may enhance treatment efficacy may unlock the possibility of modulating the gut microbiome to improve treatment using a natural approach.
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Gamal A, Elshaer M, Long L, McCormick TS, Elewski B, Ghannoum MA. Antifungal Activity of Efinaconazole Compared to Fluconazole, Itraconazole, and Terbinafine against Terbinafine- and Itraconazole-Resistant and -Susceptible Clinical Isolates of Dermatophytes, Candida, and Mold. J Am Podiatr Med Assoc 2023:1-30. [PMID: 37040333 DOI: 10.7547/22-132] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
BACKGROUND Recently, an increasing number of resistant-to-terbinafine dermatophytosis cases have been reported. Thus, identifying an alternative antifungal agent that possesses a broad-spectrum activity, including against resistant strains, is needed. METHODS In this study, we compared the antifungal activity of efinaconazole to fluconazole, itraconazole, and terbinafine against clinical isolates of dermatophyte, Candida, and molds using in vitro assays. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of each antifungal was quantified and compared. Both susceptible and resistant clinical isolates of Trichophyton mentagrophytes (n=16), T. rubrum (n=43), T. tonsurans (n=18), T. violaceum (n=4), Candida albicans (n=55), C. auris (n=30), Fusarium sp., Scedosporium sp., and Scopulariopsis sp. (n=15 for each) were tested. RESULTS Our data shows that efinaconazole was the most active antifungal, compared to the other agents tested, against dermatophytes with MIC50 and MIC90 (Concentration that inhibited 50% and 90% of strains tested, respectively) values of 0.002 and 0.03 μg/ml, respectively. Fluconazole, itraconazole and terbinafine showed MIC50 and MIC90 values of 1 and 8 μg/ml, 0.03 and 0.25 μg/ml, and 0.031 and 16 μg/ml, respectively. Against Candida isolates, efinaconazole MIC50 and MIC90 values were 0.016 and 0.25 μg/ml, respectively, whereas fluconazole, itraconazole and terbinafine had MIC50 and the MIC90 values of 1 and 16 μg/ml, 0.25 and 0.5 μg/ml, and 2 and 8 μg/ml, respectively. Against various mold species, efinaconazole MIC values ranged from 0.016 and 2 μg/ml, compared to 0.5 to greater than 64 μg/ml for the comparators. CONCLUSIONS efinaconazole showed superior potent activity against a broad panel of susceptible and resistant dermatophyte, Candida, and mold isolates.
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Hammond M, Gamal A, Mukherjee PK, Damiani G, McCormick TS, Ghannoum MA, Nedorost S. Cutaneous dysbiosis may amplify barrier dysfunction in patients with atopic dermatitis. Front Microbiol 2022; 13:944365. [PMID: 36452925 PMCID: PMC9701744 DOI: 10.3389/fmicb.2022.944365] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 10/13/2022] [Indexed: 09/12/2023] Open
Abstract
Atopic dermatitis (AD) is associated with cutaneous dysbiosis, barrier defects, and immune dysregulation, but the interplay between these factors needs further study. Early-onset barrier dysfunction may facilitate an innate immune response to commensal organisms and, consequently, the development of allergic sensitization. We aimed to compare the cutaneous microbiome in patients with active dermatitis with and without a history of childhood flexural dermatitis (atopic dermatitis). Next-gen Ion-Torrent deep-sequencing identified AD-associated changes in the skin bacterial microbiome ("bacteriome") and fungal microbiome ("mycobiome") of affected skin in swabs from areas of skin affected by dermatitis. Data were analyzed for diversity, abundance, and inter-kingdom correlations. Microbial interactions were assessed in biofilms using metabolic activity (XTT) assay and scanning electron microscopy (SEM), while host-pathogen interactions were determined in cultured primary keratinocytes exposed to biofilms. Increased richness and abundance of Staphylococcus, Lactococcus, and Alternaria were found in atopics. Staphylococcus and Alternaria formed robust mixed-species biofilms (based on XTT and SEM) that were resistant to antifungals/antimicrobials. Furthermore, their biofilm supernatant was capable of influencing keratinocytes biology (pro-inflammatory cytokines and structural proteins), suggesting an additive effect on AD-associated host response. In conclusion, microbial inter-kingdom and host-microbiome interactions may play a critical role in the modulation of atopic dermatitis to a greater extent than in non-atopic adults with allergic contact dermatitis.
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Angulo DA, Alexander B, Rautemaa-Richardson R, Alastruey-Izquierdo A, Hoenigl M, Ibrahim AS, Ghannoum MA, King TR, Azie NE, Walsh TJ. Ibrexafungerp, a Novel Triterpenoid Antifungal in Development for the Treatment of Mold Infections. J Fungi (Basel) 2022; 8:1121. [PMID: 36354888 PMCID: PMC9695964 DOI: 10.3390/jof8111121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/21/2022] [Accepted: 10/22/2022] [Indexed: 12/02/2022] Open
Abstract
Molds are ubiquitous in the environment, and immunocompromised patients are at substantial risk of morbidity and mortality due to their underlying disease and the resistance of pathogenic molds to currently recommended antifungal therapies. This combination of weakened-host defense, with limited antifungal treatment options, and the opportunism of environmental molds renders patients at risk and especially vulnerable to invasive mold infections such as Aspergillus and members of the Order Mucorales. Currently, available antifungal drugs such as azoles and echinocandins, as well as combinations of the same, offer some degree of efficacy in the prevention and treatment of invasive mold infections, but their use is often limited by drug resistance mechanisms, toxicity, drug-drug interactions, and the relative paucity of oral treatment options. Clearly, there is a need for agents that are of a new class that provides adequate tissue penetration, can be administered orally, and have broad-spectrum efficacy against fungal infections, including those caused by invasive mold organisms. Ibrexafungerp, an orally bioavailable glucan synthase inhibitor, is the first in a new class of triterpenoid antifungals and shares a similar target to the well-established echinocandins. Ibrexafungerp has a very favorable pharmacokinetic profile for the treatment of fungal infections with excellent tissue penetration in organs targeted by molds, such as the lungs, liver, and skin. Ibrexafungerp has demonstrated in vitro activity against Aspergillus spp. as well as efficacy in animal models of invasive aspergillosis and mucormycosis. Furthermore, ibrexafungerp is approved for use in the USA for the treatment of women with vulvovaginal candidiasis. Ibrexafungerp is currently being evaluated in clinical trials as monotherapy or in combination with other antifungals for treating invasive fungal infections caused by yeasts and molds. Thus, ibrexafungerp offers promise as a new addition to the clinician's armamentarium against these difficult-to-treat infections.
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Meletiadis J, Andes DR, Lockhart SR, Ghannoum MA, Knapp CC, Ostrosky-Zeichner L, Pfaller MA, Chaturvedi V, Walsh TJ. Multicenter Collaborative Study of the Interaction of Antifungal Combinations against Candida Spp. by Loewe Additivity and Bliss Independence-Based Response Surface Analysis. J Fungi (Basel) 2022; 8:jof8090967. [PMID: 36135692 PMCID: PMC9500786 DOI: 10.3390/jof8090967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/05/2022] [Accepted: 09/07/2022] [Indexed: 11/16/2022] Open
Abstract
Combination antifungal therapy is widely used but not well understood. We analyzed the spectrophotometric readings from a multicenter study conducted by the New York State Department of Health to further characterize the in vitro interactions of the major classes of antifungal agents against Candida spp. Loewe additivity-based fractional inhibitory concentration index (FICi) analysis and Bliss independence-based response surface (BIRS) analysis were used to analyze two-drug inter- and intraclass combinations of triazoles (AZO) (voriconazole, posaconazole), echinocandins (ECH) (caspofungin, micafungin, anidulafungin), and a polyene (amphotericin B) against Candida albicans, C. parapsilosis, and C. glabrata. Although mean FIC indices did not differ statistically significantly from the additivity range of 0.5−4, indicating no significant pharmacodynamic interactions for all of the strain−combinations tested, BIRS analysis showed that significant pharmacodynamic interactions with the sum of percentages of interactions determined with this analysis were strongly associated with the FIC indices (Χ2 646, p < 0.0001). Using a narrower additivity range of 1−2 FIC index analysis, statistically significant pharmacodynamic interactions were also found with FICi and were in agreement with those found with BIRS analysis. All ECH+AB combinations were found to be synergistic against all Candida strains except C. glabrata. For the AZO+AB combinations, synergy was found mostly with the POS+AB combination. All AZO+ECH combinations except POS+CAS were synergistic against all Candida strains although with variable magnitude; significant antagonism was found for the POS+MIF combination against C. albicans. The AZO+AZO combination was additive for all strains except for a C. parapsilosis strain for which antagonism was also observed. The ECH+ECH combinations were synergistic for all Candida strains except C. glabrata for which they were additive; no antagonism was found.
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Grada A, Ghannoum MA, Bunick CG. Sarecycline Demonstrates Clinical Effectiveness against Staphylococcal Infections and Inflammatory Dermatoses: Evidence for Improving Antibiotic Stewardship in Dermatology. Antibiotics (Basel) 2022; 11:antibiotics11060722. [PMID: 35740129 PMCID: PMC9220064 DOI: 10.3390/antibiotics11060722] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/20/2022] [Accepted: 05/24/2022] [Indexed: 02/04/2023] Open
Abstract
Tetracycline class antibiotics are widely used for multiple skin diseases, including acne vulgaris, acne rosacea, cutaneous infections, inflammatory dermatoses, and autoimmune blistering disorders. Concerns about antibiotic resistance and protecting the human/host microbiome beg the question whether broad-spectrum tetracyclines such as doxycycline and minocycline should be prescribed at such a high rate by dermatologists when a narrow-spectrum tetracycline derivative, sarecycline, exists. We evaluated the clinical effectiveness of oral sarecycline against cutaneous staphylococcal infections, eyelid stye, and mucous membrane pemphigoid to determine whether sarecycline is a viable option for clinicians to practice improved antibiotic stewardship. We observed significant improvement in staphylococcal infections and inflammatory dermatoses with courses of oral sarecycline as short as 9 days, with no reported adverse events. These clinical findings are consistent with in vitro microbiological data and anti-inflammatory properties of sarecycline. Our data provides a strong rationale for clinicians to use narrow-spectrum sarecycline rather than broad-spectrum tetracyclines as a first-line agent in treating staphylococcal skin infections and inflammatory skin diseases for which tetracyclines are currently commonly employed. Such advancement in the practice paradigm in dermatology will enhance antibiotic stewardship, reduce risk of antibiotic resistance, protect the human microbiome, and provide patients with precision medicine care.
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Ferrari B, Da Silva AC, Liu KH, Saidakova EV, Korolevskaya LB, Shmagel KV, Shive C, Pacheco Sanchez G, Retuerto M, Sharma AA, Ghneim K, Noel-Romas L, Rodriguez B, Ghannoum MA, Hunt PP, Deeks SG, Burgener AD, Jones DP, Dobre MA, Marconi VC, Sekaly RP, Younes SA. Gut-derived bacterial toxins impair memory CD4+ T cell mitochondrial function in HIV-1 infection. J Clin Invest 2022; 132:e149571. [PMID: 35316209 PMCID: PMC9057623 DOI: 10.1172/jci149571] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 03/16/2022] [Indexed: 11/17/2022] Open
Abstract
People living with HIV (PLWH) who are immune nonresponders (INRs) are at greater risk of comorbidity and mortality than are immune responders (IRs) who restore their CD4+ T cell count after antiretroviral therapy (ART). INRs have low CD4+ T cell counts (<350 c/μL), heightened systemic inflammation, and increased CD4+ T cell cycling (Ki67+). Here, we report the findings that memory CD4+ T cells and plasma samples of INRs from several cohorts are enriched in gut-derived bacterial solutes p-cresol sulfate (PCS) and indoxyl sulfate (IS) that both negatively correlated with CD4+ T cell counts. In vitro PCS or IS blocked CD4+ T cell proliferation, induced apoptosis, and diminished the expression of mitochondrial proteins. Electron microscopy imaging revealed perturbations of mitochondrial networks similar to those found in INRs following incubation of healthy memory CD4+ T cells with PCS. Using bacterial 16S rDNA, INR stool samples were found enriched in proteolytic bacterial genera that metabolize tyrosine and phenylalanine to produce PCS. We propose that toxic solutes from the gut bacterial flora may impair CD4+ T cell recovery during ART and may contribute to CD4+ T cell lymphopenia characteristic of INRs.
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Mohamed A, Asa SL, McCormick T, Al-Shakhshir H, Dasari A, Mauricio R, Salem I, Ocuin LM, Bajor D, Lee RT, Selfridge JE, Kardan A, Lee Z, Avril N, Kopp S, Winter JM, Hardacre JM, Ammori JB, Ghannoum MA. The Role of the Microbiome in Gastroentero-Pancreatic Neuroendocrine Neoplasms (GEP-NENs). Curr Issues Mol Biol 2022; 44:2015-2028. [PMID: 35678665 PMCID: PMC9164086 DOI: 10.3390/cimb44050136] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 04/19/2022] [Accepted: 04/27/2022] [Indexed: 11/16/2022] Open
Abstract
Gut microbiome balance plays a key role in human health and maintains gut barrier integrity. Dysbiosis, referring to impaired gut microbiome, is linked to a variety of diseases, including cancers, through modulation of the inflammatory process. Most studies concentrated on adenocarcinoma of different sites with very limited information on gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). In this study, we have analyzed the gut microbiome (both fungal and bacterial communities) in patients with metastatic GEP-NENs. Fecal samples were collected and compared with matched healthy control samples using logistic regression distances utilizing R package MatchIt (version 4.2.0, Daniel E. Ho, Stanford, California). We examined differences in microbiome profiles between GEP-NENs and control samples using small subunit (SSU) rRNA (16S), ITS1, ITS4 genomic regions for their ability to accurately characterize bacterial and fungal communities. We correlated the results with different behavioral and dietary habits, and tumor features including differentiation, grade, primary site, and therapeutic response. All tests are two-sided and p-values ≤ 0.05 were considered statistically significant. Gut samples of 34 patients (12 males, 22 females, median age 64 years) with metastatic GEP-NENs (22 small bowel, 10 pancreatic, 1 gall bladder, and 1 unknown primary) were analyzed. Twenty-nine patients had well differentiated GEP-neuroendocrine tumors (GEP-NETs), (G1 = 14, G2 = 12, G3 = 3) and five patients had poorly differentiated GEP-neuroendocrine carcinomas (GEP-NECs). Patients with GEP-NENs had significantly decreased bacterial species and increased fungi (notably Candida species, Ascomycota, and species belonging to saccharomycetes) compared to controls. Patients with GEP-NECs had significantly enriched populations of specific bacteria and fungi (such as Enterobacter hormaechei, Bacteroides fragilis and Trichosporon asahii) compared to those with GEP-NETs (p = 0.048, 0.0022 and 0.034, respectively). In addition, higher grade GEP-NETs were associated with significantly higher Bacteroides fragilis (p = 0.022), and Eggerthella lenta (p = 0.00018) species compared to lower grade tumors. There were substantial differences associated with dietary habits and therapeutic responses. This is the first study to analyze the role of the microbiome environment in patients with GEP-NENs. There were significant differences between GEP-NETs and GEP-NECs, supporting the role of the gut microbiome in the pathogenesis of these two distinct entities.
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Gupta AK, Hall DC, Cooper EA, Ghannoum MA. Diagnosing Onychomycosis: What’s New? J Fungi (Basel) 2022; 8:jof8050464. [PMID: 35628720 PMCID: PMC9146047 DOI: 10.3390/jof8050464] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 02/05/2023] Open
Abstract
An overview of the long-established methods of diagnosing onychomycosis (potassium hydroxide testing, fungal culture, and histopathological examination) is provided followed by an outline of other diagnostic methods currently in use or under development. These methods generally use one of two diagnostic techniques: visual identification of infection (fungal elements or onychomycosis signs) or organism identification (typing of fungal genus/species). Visual diagnosis (dermoscopy, optical coherence tomography, confocal microscopy, UV fluorescence excitation) provides clinical evidence of infection, but may be limited by lack of organism information when treatment decisions are needed. The organism identification methods (lateral flow techniques, polymerase chain reaction, MALDI-TOF mass spectroscopy and Raman spectroscopy) seek to provide faster and more reliable identification than standard fungal culture methods. Additionally, artificial intelligence methods are being applied to assist with visual identification, with good success. Despite being considered the ‘gold standard’ for diagnosis, clinicians are generally well aware that the established methods have many limitations for diagnosis. The new techniques seek to augment established methods, but also have advantages and disadvantages relative to their diagnostic use. It remains to be seen which of the newer methods will become more widely used for diagnosis of onychomycosis. Clinicians need to be aware of the limitations of diagnostic utility calculations as well, and look beyond the numbers to assess which techniques will provide the best options for patient assessment and management.
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McCormick TS, Hejal RB, Leal LO, Ghannoum MA. GM-CSF: Orchestrating the Pulmonary Response to Infection. Front Pharmacol 2022; 12:735443. [PMID: 35111042 PMCID: PMC8803133 DOI: 10.3389/fphar.2021.735443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 12/13/2021] [Indexed: 01/18/2023] Open
Abstract
This review summarizes the structure and function of the alveolar unit, comprised of alveolar macrophage and epithelial cell types that work in tandem to respond to infection. Granulocyte-macrophage colony-stimulating factor (GM-CSF) helps to maintain the alveolar epithelium and pulmonary immune system under physiological conditions and plays a critical role in restoring homeostasis under pathologic conditions, including infection. Given the emergence of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and global spread of coronavirus disease 2019 (COVID-19), with subsequent acute respiratory distress syndrome, understanding basic lung physiology in infectious diseases is especially warranted. This review summarizes clinical and preclinical data for GM-CSF in respiratory infections, and the rationale for sargramostim (yeast-derived recombinant human [rhu] GM-CSF) as adjunctive treatment for COVID-19 and other pulmonary infectious diseases.
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16
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Herrada J, Gamal A, Long L, Ghannoum MA. In Vivo Skin Colonization and Decolonization Models for Candida auris. Methods Mol Biol 2022; 2517:269-285. [PMID: 35674962 DOI: 10.1007/978-1-0716-2417-3_22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Candida auris infections present a critical problem to the healthcare system in many parts of the world. This yeast clinically manifests as a disseminated candidiasis which can be life-threating for susceptible individuals, as well as cutaneous and wound infections. Moreover, C. auris can colonize the skin and act as a nidus of infection. Importantly, this emerging yeast unlike other Candida spp. has demonstrated multidrug resistance; thus its eradication can be challenging. Animal models are important to gain insight into the pathogenesis of this infection, as well as play a significant role in drug development. In this chapter, we describe two C. auris animal models: a cutaneous infection guinea pig model and a skin decolonization mouse model.
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17
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Herrada J, Roberts K, Gamal A, Long L, Ghannoum MA. An Immunocompromised Mouse Model of Candida auris Systemic Infection. Methods Mol Biol 2022; 2517:317-328. [PMID: 35674965 PMCID: PMC10617627 DOI: 10.1007/978-1-0716-2417-3_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
With the recent emergence of multidrug-resistant Candida auris, there is an urgent need for new antifungal compounds with novel pharmacodynamic and pharmacokinetic properties that can treat systemic fungal infections caused by this emerging yeast. Historically, testing the efficacy of treatment for disseminated candidiasis was accomplished using a diverse array of in vivo animal models, including mice which offer an advantage both in their similarities to humans and their lower cost of maintenance. However, in order to create effective in vivo models for testing new antifungal compounds designed to treat systemic infections, it is important that these models also mimic several of the relevant predisposing conditions that can lead to disseminated candidiasis. Here, we describe an immunocompromised mouse model of hematogenously disseminated C. auris infection, which may have utility to test the efficacy of candidate antifungal compounds.
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18
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Gamal A, Kadry A, Elshaer M, Ghannoum MA. Novel Antifungals for the Treatment of Vulvovaginal Candidiasis: Where Are We? Infect Dis (Lond) 2022. [DOI: 10.17925/id.2022.1.1.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Vulvovaginal candidiasis (VVC) is a common health-related issue and the second most common cause of vaginitis. Previously, azole antifungals were the mainstay of VVC treatment. Additionally, boric acid and nystatin have been used topically for management of VVC. Despite being effective and well tolerated by most patients, the use of azoles may be limited in some cases. Currently, two new antifungal agents have received US Food and Drug Administration approval for use in the management of VVC. In this article, we briefly review treatment regimens used for the management of VVC over the past decade, the newly approved agents and their possible clinical application, and future treatment considerations.
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Sobel R, Nyirjesy P, Ghannoum MA, Delchev DA, Azie NE, Angulo D, Harriott IA, Borroto-Esoda K, Sobel JD. Efficacy and safety of oral ibrexafungerp for the treatment of acute vulvovaginal candidiasis: a global phase 3, randomised, placebo-controlled superiority study (VANISH 306). BJOG 2021; 129:412-420. [PMID: 34676663 PMCID: PMC9299454 DOI: 10.1111/1471-0528.16972] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 08/30/2021] [Accepted: 09/08/2021] [Indexed: 01/25/2023]
Abstract
Objective To evaluate the efficacy and safety of ibrexafungerp versus placebo for acute vulvovaginal candidiasis (VVC) treatment. Design Global phase 3, randomised, placebo‐controlled superiority study. Setting Study sites in the USA (n = 19) and Bulgaria (n = 18). Population Female patients aged ≥12 years with acute VVC and a vulvovaginal signs and symptoms (VSS) score ≥4 at baseline. Methods Patients were randomly assigned 2:1 to ibrexafungerp (300 mg twice for 1 day) or placebo. Main outcome measures The primary endpoint was the percentage of patients with a clinical cure (VSS = 0) at the test‐of‐cure visit (day 11 ± 3). Secondary endpoints included percentages of patients with mycological eradication, clinical cure and mycological eradication (overall success), clinical improvement (VSS ≤1) at test‐of‐cure visit, and complete resolution of symptoms at follow‐up visit (day 25 ± 4). Results At the test‐of‐cure visit, patients receiving ibrexafungerp had significantly higher rates of clinical cure (63.3% [119/188] versus 44.0% [37/84]; P = 0.007), mycological eradication (58.5% [110/188] versus 29.8% [25/84]; P < 0.001), overall success (46.1% [82/188] versus 28.4% [23/84]; P = 0.022) and clinical improvement (72.3% [136/188] versus 54.8% [46/84]; P = 0.01) versus those receiving placebo. Symptom resolution was sustained and further increased with ibrexafungerp (73.9%) versus placebo (52.4%) at follow‐up (P = 0.001). Ibrexafungerp was generally well tolerated. Adverse events were primarily gastrointestinal and were mild to moderate in severity. Conclusions Ibrexafungerp demonstrated statistical superiority over placebo for the primary and secondary endpoints. Ibrexafungerp is a promising novel, well‐tolerated and effective oral 1‐day treatment for acute VVC. Tweetable abstract Ibrexafungerp is statistically superior to placebo for the treatment of vulvovaginal candidiasis. Ibrexafungerp is statistically superior to placebo for the treatment of vulvovaginal candidiasis. Linked article This article is commented on by KSJ Olah, p. 421–422 in this issue. To view this mini commentary visit https://doi.org/10.1111/1471-0528.17000.
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20
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Schwebke JR, Sobel R, Gersten JK, Sussman SA, Lederman SN, Jacobs MA, Chappell BT, Weinstein DL, Moffett AH, Azie NE, Angulo DA, Harriott IA, Borroto-Esoda K, Ghannoum MA, Nyirjesy P, Sobel JD. Ibrexafungerp versus placebo for vulvovaginal candidiasis treatment: a phase 3, randomized, controlled superiority trial (VANISH 303). Clin Infect Dis 2021; 74:1979-1985. [PMID: 34467969 PMCID: PMC9187327 DOI: 10.1093/cid/ciab750] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Indexed: 01/20/2023] Open
Abstract
Background Current treatment of vulvovaginal candidiasis (VVC) is largely limited to azole therapy. Ibrexafungerp is a first-in-class triterpenoid antifungal with broad-spectrum anti-Candida fungicidal activity. The objective of this study was to evaluate the efficacy and safety of ibrexafungerp compared with placebo in patients with acute VVC. Methods Patients were randomly assigned 2:1 to receive ibrexafungerp (300 mg twice for 1 day) or placebo. The primary endpoint was the percentage of patients with a clinical cure (complete resolution of vulvovaginal signs and symptoms [VSS] = 0) at test-of-cure (day 11 ± 3). Secondary endpoints included the percentage of patients with mycological eradication, overall success (clinical cure and mycological eradication), clinical improvement (VSS ≤ 1) at test-of-cure, and symptom resolution at follow-up (day 25 ± 4). Results Patients receiving ibrexafungerp had significantly higher rates of clinical cure (50.5% [95/188] vs 28.6% [28/98]; P = .001), mycological eradication (49.5% [93/188] vs 19.4% [19/98]; P < .001), and overall success (36.0% [64/178] vs 12.6% [12/95]; P < .001) compared with placebo. Symptom resolution was sustained and further increased with ibrexafungerp compared with placebo (59.6% [112/188] vs 44.9% [44/98]; P = .009) at follow-up. Post hoc analysis showed similar rates of clinical cure and clinical improvement at test-of-cure for Black patients (54.8% [40/73] and 63.4% [47/73], respectively) and patients with a body mass index >35 (54.5% [24/44] and 68.2% [30/44], respectively) compared with overall rates. Ibrexafungerp was well tolerated. Adverse events were primarily gastrointestinal and mild in severity. Conclusions Ibrexafungerp provides a promising safe and efficacious oral treatment that mechanistically differs from current azole treatment options for acute VVC.
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21
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Ghannoum MA, Ford M, Bonomo RA, Gamal A, McCormick TS. A Microbiome-Driven Approach to Combating Depression During the COVID-19 Pandemic. Front Nutr 2021; 8:672390. [PMID: 34504858 PMCID: PMC8421528 DOI: 10.3389/fnut.2021.672390] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 07/30/2021] [Indexed: 12/18/2022] Open
Abstract
The significant stressors brought about and exacerbated by COVID-19 are associated with startling surges in mental health illnesses, specifically those related to depressive disorders. Given the huge impact of depression on society, and an incomplete understanding of impactful therapeutics, we have examined the current literature surrounding the microbiome and gut-brain axis to advance a potential complementary approach to address depression and depressive disorders that have increased during the COVID-19 pandemic. While we understand that the impact of the human gut microbiome on emotional health is a newly emerging field and more research needs to be conducted, the current evidence is extremely promising and suggests at least part of the answer to understanding depression in more depth may lie within the microbiome. As a result of these findings, we propose that a microbiome-based holistic approach, which involves carefully annotating the microbiome and potential modification through diet, probiotics, and lifestyle changes, may address depression. This paper's primary purpose is to shed light on the link between the gut microbiome and depression, including the gut-brain axis and propose a holistic approach to microbiome modification, with the ultimate goal of assisting individuals to manage their battle with depression through diet, probiotics, and lifestyle changes, in addition to offering a semblance of hope during these challenging times.
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22
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Cheng OT, Stein AP, Babajanian E, Hoppe KR, Li S, Jung H, Abrol A, Akkus A, Younesi M, Altawallbeh G, Ghannoum MA, Bonfield T, Akkus O, Zender CA. Heparin-mediated antibiotic delivery from an electrochemically-aligned collagen sheet. Biomed Mater Eng 2021; 32:159-170. [PMID: 33780355 DOI: 10.3233/bme-201133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Implantable medical devices and hardware are prolific in medicine, but hardware associated infections remain a major issue. OBJECTIVE To develop and evaluate a novel, biologic antimicrobial coating for medical implants. METHODS Electrochemically compacted collagen sheets with and without crosslinked heparin were synthesized per a protocol developed by our group. Sheets were incubated in antibiotic solution (gentamicin or moxifloxacin) overnight, and in vitro activity was assessed with five-day diffusion assays against Pseudomonas aeruginosa. Antibiotic release over time from gentamicin-infused sheets was determined using in vitro elution and high performance liquid chromatography (HPLC). RESULTS Collagen-heparin-antibiotic sheets demonstrated larger growth inhibition zones against P. aeruginosa compared to collagen-antibiotic alone sheets. This activity persisted for five days and was not impacted by rinsing sheets prior to evaluation. Rinsed collagen-antibiotic sheets did not produce any inhibition zones. Elution of gentamicin from collagen-heparin-gentamicin sheets was gradual and remained above the minimal inhibitory concentration for gentamicin-sensitive organisms for 29 days. Conversely, collagen-gentamicin sheets eluted their antibiotic load within 24 hours. Overall, heparin-associated sheets demonstrated larger inhibition zones against P. aeruginosa and prolonged elution profile via HPLC. CONCLUSION We developed a novel, local antibiotic delivery system that could be used to coat medical implants/hardware in the future and reduce post-operative infections.
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Chu S, McCormick TS, Lazarus HM, Leal LO, Ghannoum MA. Invasive fungal disease and the immunocompromised host including allogeneic hematopoietic cell transplant recipients: Improved understanding and new strategic approach with sargramostim. Clin Immunol 2021; 228:108731. [PMID: 33892201 DOI: 10.1016/j.clim.2021.108731] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/12/2021] [Accepted: 04/17/2021] [Indexed: 12/17/2022]
Abstract
In hosts with damaged or impaired immune systems such as those undergoing hematopoietic cell transplant (HCT) or intensive chemotherapy, breakthrough fungal infections can be fatal. Risk factors for breakthrough infections include severe neutropenia, use of corticosteroids, extended use of broad-spectrum antibiotics, and intensive care unit admission. An individual's cumulative state of immunosuppression directly contributes to the likelihood of experiencing increased infection risk. Incidence of invasive fungal infection (IFI) after HCT may be up to 5-8%. Early intervention may improve IFI outcomes, although many infections are resistant to standard therapies (voriconazole, caspofungin, micafungin, amphotericin B, posaconazole or itraconazole, as single agents or in combination). We review herein several contributing factors that may contribute to the net state of immunosuppression in recipients of HCT. We also review a new approach for IFI utilizing adjunctive therapy with sargramostim, a yeast-derived recombinant human granulocyte-macrophage colony-stimulating factor (rhu GM-CSF).
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Gamal A, Chu S, McCormick TS, Borroto-Esoda K, Angulo D, Ghannoum MA. Ibrexafungerp, a Novel Oral Triterpenoid Antifungal in Development: Overview of Antifungal Activity Against Candida glabrata. Front Cell Infect Microbiol 2021; 11:642358. [PMID: 33791244 PMCID: PMC8006402 DOI: 10.3389/fcimb.2021.642358] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/05/2021] [Indexed: 12/12/2022] Open
Abstract
Systemic infections caused by Candida species are an important cause of morbidity and mortality among immunocompromised and non-immunocompromised patients. In particular, Candida glabrata is an emerging species within the Candida family that causes infections ranging from superficial to life-threatening systemic disease. Echinocandins and azoles are typically the first-line therapies used to treat infections caused by C. glabrata, however, there is an increasing prevalence of resistance to these antifungal agents in patients. Thus, a need exists for novel therapies that demonstrate high efficacy against C. glabrata. Ibrexafungerp is a first-in-class glucan synthase inhibitor with oral availability developed to address this increasing antifungal resistance. Ibrexafungerp demonstrates broad in vitro activity against wild-type, azole-resistant, and echinocandin-resistant C. glabrata species. Furthermore, ibrexafungerp has shown efficacy in low pH environments, which suggests its potential effectiveness in treating vulvovaginal candidiasis. Additional preclinical and clinical studies are needed to further examine the mechanism(s) of ibrexafungerp, including acting as a promising new agent for treating C. glabrata infections.
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Miyagi M, Wilson R, Saigusa D, Umeda K, Saijo R, Hager CL, Li Y, McCormick T, Ghannoum MA. Indole-3-acetic acid synthesized through the indole-3-pyruvate pathway promotes Candida tropicalis biofilm formation. PLoS One 2020; 15:e0244246. [PMID: 33332404 PMCID: PMC7746184 DOI: 10.1371/journal.pone.0244246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 12/04/2020] [Indexed: 12/26/2022] Open
Abstract
We previously found that the elevated abundance of the fungus Candida tropicalis is positively correlated with the bacteria Escherichia coli and Serratia marcescens in Crohn’s disease patients and the three pathogens, when co-cultured, form a robust mixed-species biofilm. The finding suggests that these three pathogens communicate and promote biofilm formation, possibly through secretion of small signaling molecules. To identify candidate signaling molecules, we carried out a metabolomic analysis of the single-species and triple-species cultures of the three pathogens. This analysis identified 15 metabolites that were highly increased in the triple-species culture. One highly induced metabolite was indole-3-acetic acid (IAA), which has been shown to induce filamentation of certain fungi. We thus tested the effect of IAA on biofilm formation of C. tropicalis and demonstrated that IAA promotes biofilm formation of C. tropicalis. Then, we carried out isotope tracing experiments using 13C-labeled-tryptophan as a precursor to uncover the biosynthesis pathway of IAA in C. tropicalis. The results indicated that C. tropicalis synthesizes IAA through the indole-3-pyruvate pathway. Further studies using inhibitors of the indole-3-pyruvate pathway are warranted to decipher the mechanisms by which IAA influences biofilm formation.
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