Fungal Biofilms and Drug Resistance

Candida species, including the novel opportunistic pathogen Candida dubliniensis, are now emerging as major agents of nosocomial infections. Many such manifestations of infections associated with the formation of Candida biofilms include those occurring on devices such as indwelling intravascular catheters. Fungal biofilm-associated infections are frequently refractory to conventional therapy because of resistance to antimicrobial agents. This resistance could be in part due to the surface-induced upregulation of drug efflux pumps. Biofilm-associated Candida show uniform resistance to a wide spectrum of the currently available conventional antifungal agents, which implies that antimicrobial drugs that specifically target biofilm-associated infections are needed. The novel classes of antifungal agents, the lipid formulation of amphotericins, and the echinocandins have demonstrated unique antifungal activity against the resistant Candida biofilms, providing a breakthrough in the treatment of life-threatening invasive systemic mycoses. The use of drugs effective in combating biofilm-associated infections could lead to major developments in the treatment of fungal implant infections

Oral mucosal injury caused by mammalian target of rapamycin inhibitors: emerging perspectives on pathobiology and impact on clinical practice.

In recent years oral mucosal injury has been increasingly recognized as an important toxicity associated with mammalian target of rapamycin (mTOR) inhibitors, including in patients with breast cancer who are receiving everolimus. This review addresses the state-of-the-science regarding mTOR inhibitor-associated stomatitis (mIAS), and delineates its clinical characteristics and management. Given the clinically impactful pain associated with mIAS, this review also specifically highlights new research focusing on the study of the molecular basis of pain. The incidence of mIAS varies widely (2-78%). As reported across multiple mTOR inhibitor clinical trials, grade 3/4 toxicity occurs in up to 9% of patients. Managing mTOR-associated oral lesions with topical oral, intralesional, and/or systemic steroids can be beneficial, in contrast to the lack of evidence supporting steroid treatment of oral mucositis caused by high-dose chemotherapy or radiation. However, steroid management is not uniformly efficacious in all patients receiving mTOR inhibitors. Furthermore, technology does not presently exist to permit clinicians to predict a priori which of their patients will develop these lesions. There thus remains a strategic need to define the pathobiology of mIAS, the molecular basis of pain, and risk prediction relative to development of the clinical lesion. This knowledge could lead to novel future interventions designed to more effectively prevent mIAS and improve pain management if clinically significant mIAS lesions develop

A Novel Immune Evasion Strategy of Candida albicans: Proteolytic Cleavage of a Salivary Antimicrobial Peptide

Oropharyngeal candidiasis is an opportunistic infection considered to be a harbinger of AIDS. The etiologic agent Candida albicans is a fungal species commonly colonizing human mucosal surfaces. However, under conditions of immune dysfunction, colonizing C. albicans can become an opportunistic pathogen causing superficial or even life-threatening infections. The reasons behind this transition, however, are not clear. In the oral cavity, salivary antimicrobial peptides are considered to be an important part of the host innate defense system in the prevention of microbial colonization. Histatin-5 specifically has exhibited potent activity against C. albicans. Our previous studies have shown histatin-5 levels to be significantly reduced in the saliva of HIV+ individuals, indicating an important role for histatin-5 in keeping C. albicans in its commensal stage. The versatility in the pathogenic potential of C. albicans is the result of its ability to adapt through the regulation of virulence determinants, most notably of which are proteolytic enzymes (Saps), involved in tissue degradation. In this study, we show that C. albicans cells efficiently and rapidly degrade histatin-5, resulting in loss of its anti-candidal potency. In addition, we demonstrate that this cellular activity is due to proteolysis by a member of the secreted aspartic proteases (Sap) family involved in C. albicans pathogenesis. Specifically, the proteolysis was attributed to Sap9, in turn identifying histatin-5 as the first host-specific substrate for that isoenzyme. These findings demonstrate for the first time the ability of a specific C. albicans enzyme to degrade and deactivate a host antimicrobial peptide involved in the protection of the oral mucosa against C. albicans, thereby providing new insights into the factors directing the transition of C. albicans from commensal to pathogen, with important clinical implications for alternative therapy. This report characterizes the first defined mechanism behind the enhanced susceptibility of HIV+ individuals to oral candidiasis since the emergence of HIV

Recognition and Management of Oral Mucosal Injury Caused by Mammalian Target of Rapamycin Inhibitors: A Case Series

The mammalian target of rapamycin inhibitors (mTORIs) everolimus and temsirolimus are approved by the US Food and Drug Administration (FDA) for the treatment of various forms of advanced cancer, and the mTORI sirolimus is approved as an immunosuppressive agent for the prophylaxis of organ rejection in patients receiving renal transplants. The oral lesions associated with mTORI toxicity are distinct from the well-documented chemotherapy- and radiotherapy-induced mucositis, but they may often be misdiagnosed by medical oncologists or transplant physicians, potentially resulting in inappropriate management of this complication. mTORI-associated oral mucosal injury appears to be dose related, and its onset is consistently earlier than conventional mucositis associated with chemotherapy or radiation therapy. Although the lesions appear to resolve within approximately 2 weeks and do not seem to recur as severely with subsequent courses of therapy, the reduction in a patient's quality of life as a result of oral pain that affects the intake of nutritional foods should be taken into consideration. We report three cases that illustrate the complexity involved in the early assessment, referral, and appropriate management of mTORI-associated oral mucosal injury. Corticosteroids appear to be very useful in managing and perhaps preventing these lesions, whereas this approach has never shown efficacy in conventional chemotherapy-related mucositis. Early intervention to reduce the mTORI-associated oral mucosal injury is important to diminish the need for dose alterations of mTORIs and, therefore, to improve patient outcomes

Alternative Therapeutic Approach in the Treatment of Oral Pyogenic Granuloma

Pyogenic granulomas (PGs) in the oral cavity present as an inflammatory hyperplasia usually caused by trauma, hormonal imbalance, chronic irritation, or as the response to a wide variety of drugs. PGs with atypical presentation and behavior may clinically mimic malignant tumors. Thus, histological examination is required to rule out cancer development. Lesions in the oral cavity have been described to be either an isolated entity or present in multiple forms and with multiple recurrences. Conservative surgical excision is the standard choice of treatment in almost every scenario. However, the severity of the lesions and the affected sites often challenge surgical treatment. In this report, we describe the clinical scenario of a recurrent PG, where surgical excision of the lesion was questioned. As an alternative, we describe a noninvasive approach with lesional steroid injections

370 Point-of-Service Salivary Microbiome Analysis in the Prevention and Detection of Oral Premalignant Lesions

OBJECTIVES/GOALS: Our aim is to establish soluble salivary biomarkers indicative of increased risk of oral premalignancy to be used in a point-of-service technology. Our goal is to non-invasively assess risk level for premalignancy by characterizing a molecular signature pattern that can be applied to such a diagnostic tool at routine dental or medical visits. METHODS/STUDY POPULATION: Adult patients 18 years of age and older who are non-smokers and patients of the University of Maryland School of Dentistry Oral Medicine Clinic and have been diagnosed with oral premalignancy (proliferative verrucous leukoplakia) are eligible. Exclusion criteria include history of immunosuppression or immune compromise; use of antifungal, antibiotic, and/or antiviral medications within the past three months; and gross dental disease. Serial unstimulated saliva samples will be collected at baseline or diagnosis of oral premalignancy, 6 months and 12 months. Solubility testing will be completed to determine whether malignant markers such as EGFR/mTOR/PI3K/p53 are soluble in saliva, and patient samples will be analyzed by ELISA and compared to appropriate controls. RESULTS/ANTICIPATED RESULTS: We anticipate demonstrating increased activity of molecular pathways known to be involved in malignant transformation, such as EGFR/mTOR/PI3K/p53, or increased burden of select microbial pathogens to be associated with increased risk of oral premalignancy in the form of proliferative verrucous leukoplakia. Preliminary sensitivity and specificity testing of the identified markers will provide additional insight to the utility of a diagnostic tool with salivary specimen. Therefore, the microbiome and/or molecular profile proposed from these results will serve as a translational application to development of future point-of-service test devices to be used in the prevention and detection of oral premalignant lesions. DISCUSSION/SIGNIFICANCE: Oral cancer is the sixth most common cancer worldwide, and presents challenges in its diagnosis and clinical management. Later diagnosis is associated with poorer patient outcomes—therefore, a molecular and microbiome profile that may be used in a noninvasive diagnostic test technology would prove beneficial to providers and patients