The prevalence of oral lesions in HIV-infected homosexual and bisexual men: three San Francisco epidemiological cohorts

An Appreciation of a Giant in Orofacial Sciences Research-John Greenspan

Professor John S. Greenspan died on March 31, 2023. He was a renowned and accomplished academic, dentist/scientist, pathologist, and administrator who made sustained and significant international impacts on numerous fields over half a century. John was arguably best known for his work with his wife, Dr. Deborah Greenspan, on the oral aspects of AIDS and the role of viruses in oral epithelial and salivary gland lesions. He had a lifelong interest in Sjögren's syndrome, culminating in the leadership of the Sjögren's International Collaborative Clinical Alliance. He was also widely recognized as one of the leading investigators into the understanding of oral mucosal diseases, including recurrent aphthous stomatitis. He and his colleagues' major contributions to HIV research and care included the discovery of the oral lesion "hairy leukoplakia," its etiological association with Epstein-Barr virus, and other oral lesions in the natural history of HIV disease. In recent years, John turned his attention to global oral health inequalities, helping to establish the International Association for Dental Research's Global Oral Health Inequalities Research Network and serving as its first president. He led many organizations with humble authority, knowledge, wit, and wisdom and mentored colleagues from all over the world, especially from lower- and middle-income countries. John leaves a very special legacy based on example and scientific curiosity, and his work has not only made a lasting impact on his colleagues but also translated to abiding benefit for patients.

Evaluation of oral care protocols practice by dentists in Rio de Janeiro towards HIV/AIDS individuals

Background

The aim of this study was to evaluate the dentists’ knowledge and practice regarding HIV positive individuals’ oral care in Rio de Janeiro State.

Methods

Dentists from Rio de Janeiro State (n = 242) answered an electronic questionnaire on biosafety procedures, oral manifestations of AIDS, and knowledge of HIV infection. Collected information was stratified by gender, and data were analyzed using Chi-square and t tests.

Results

From the 14 oral manifestations investigated, oral candidiasis, necrotizing ulcerative gingivitis, and hairy leucoplakia were more associated with HIV, with no differences between the responses from men and women. Above 85% of the participants would be concerned about becoming infected with HIV after a needle/ sharp object injury and more than 80% of them were willing to be tested for HIV. However, significantly more women (98.8%), compared to men (91.3%), said they knew that HIV/ AIDS patients can contaminate dental care professionals, p = 0.007. There was a significant difference in the answers for the questions: “Are there special dental clinics for treatment of HIV/AIDS patients in Brazil?” (p = 0.044), and “Do the negative HIV tests surely indicate that the persons are free of viruses?” (p = 0.005). Significant differences between men and women were also observed regarding use of disposable mask (p = 0.01), and cap (p < 0.0001).

Conclusion

Most dentists who participated in the study presented a good knowledge on the care of HIV/ AIDS individuals, including biosafety protocols and in terms of the oral manifestations commonly associated to AIDS.

T Cell Antifungal Immunity and the Role of C-Type Lectin Receptors. Trends Immunol. 2019;. [PMID: 31813764 PMCID: PMC7427322 DOI: 10.1016/j.it.2019.11.007]

Fungi can cause disease in humans, from mucocutaneous to life-threatening systemic infections. Initiation of antifungal immunity involves fungal recognition by pattern recognition receptors such as C-type lectin receptors (CLRs). These germline-encoded receptors trigger a multitude of innate responses including phagocytosis, fungal killing, and antigen presentation which can also shape the development of adaptive immunity. Recently, studies have shed light on how CLRs directly or indirectly modulate lymphocyte function. Moreover, CLR-mediated recognition of commensal fungi maintains homeostasis and prevents invasion from opportunistic commensals. We present an overview of current knowledge of antifungal T cell immune responses, with emphasis on the role of C-type lectins, and discuss how these receptors modulate these responses at different levels.

CLRs are essential pattern recognition receptors involved in fungal recognition and initiation of protective antifungal immunity.

CLRs promote the differentiation of mammalian T helper cell subsets essential for the control of systemic (Th1) and mucosal (Th17) fungal infections.

CLRs are involved in antigen presentation, the expression of co-stimulatory molecules, and cytokine secretion; therefore, they can regulate lymphocyte function and adaptive immune responses at different levels.

Fungal morphological changes, such as the transition from yeast to hyphae in Candida albicans during tissue invasion, affects recognition by CLRs and impacts on adaptive immune responses.

CLRs recognize the fungal component of the microbiome that can influence T cell responses during infection at intestinal and peripheral sites.

Evaluation of dental students' knowledge and patient care towards HIV/AIDS individuals

PURPOSE

The aim was to evaluate the knowledge of the students of dental students regarding patients care towards HIV positive individuals.

METHODS

Two hundred and eighty-three dental students (pre-clinical, n = 45; clinical, n = 238) answered an electronic questionnaire, approaching biosafety procedures, oral manifestations of AIDS and knowledge of HIV infection. Data were present as an average from findings from students of nine different semesters, grouping them by pre-clinical (1-4) and clinical (5-9) semesters, from two different university campuses. Furthermore, data were analysed using the t test and chi-square test.

RESULTS

Students' mean age was 24 years. Amongst 14 oral manifestations questioned, Kaposi sarcoma, oral candidiasis, necrotizing ulcerative gingivitis and herpes simplex were more associated with HIV. Over 90% of the respondents would be concerned about becoming infected with HIV after a needle stick injury and were willing to be tested for HIV; know that HIV/AIDS patients can contaminate dental care professionals, that needle perforation can transmit HIV, and that medical professionals are more prone to cross-contamination. Regarding the use of physical barrier, almost all participants use disposable mask, goggles, cap and procedure gloves with all patients; the use of disposable lab coat and two pairs of gloves were the least used with all patients.

CONCLUSIONS

Participating students have good knowledge on biosafety in the management of HIV/AIDS patients, as well as on the most commonly associated oral manifestations. However, there is a need for improvement on some topics related to HIV/AIDS, especially regarding less known oral lesions, and HIV diagnostic tests.

Predictors of esophageal candidiasis among patients attending endoscopy unit in a tertiary hospital, Tanzania: a retrospective cross-sectional study

Background

Esophageal candidiasis is a common disease among patients with impaired cell mediated immunity. In the current study, we report esophageal candidiasis among patients with various co-morbidities attending the endoscopic unit at the Bugando Medical Centre.

Methods

This retrospective study was conducted from June to September 2015. All data of the patients who attended the endoscopic unit between 2009 and 2014 were retrieved and analyzed.

Results

A total of 622 patients who underwent oesophagogastroduodenoscopy were analyzed. A slight majority 334/622(53.7%) of patients were female. Out of 622 patients; 35(5.6%) had esophageal candidiasis. Decrease in age (OR 1.1, 95%CI; 1.0–1.1), female sex (OR 3.8, 95%CI; 1.1–13.1), drinking alcohol (OR 17.1, 95%CI; 4.9–58.9), smoking (OR 8.3, 95%CI; 1.7–41.0), antibiotic use (OR 5.7, 95%CI; 2.0–16.4), positive HIV status (OR 10.3, 95%CI; 4.6–6.0) and presence of peptic ulcer disease (OR 13.2, 95%CI; 3.5–49.0) independently predicted esophageal candidiasis.

Conclusion

Patients with a history of drinking alcohol, smoking, use of antibiotics and those with chronic diseases such as peptic ulcers were at high risk of developing esophageal candidiasis. Further studies are needed to identify Candida spp. and their anti-fungal susceptibility for proper management of esophageal candidiasis in HIV and non-HIV individuals.

Autoimmunity and dysmetabolism of human acquired immunodeficiency syndrome

Acquired immunodeficiency syndrome (AIDS) remains ill-defined by lists of symptoms, infections, tumors, and disorders in metabolism and immunity. Low CD4 cell count, severe loss of body weight, pneumocystis pneumonia, and Kaposi's sarcoma are the major disease indicators. Lines of evidence indicate that patients living with AIDS have both immunodeficiency and autoimmunity. Immunodeficiency is attributed to deficits in the skin- and mucosa-defined innate immunity, CD4 T cells and regulatory T cells, presumably relating human immunodeficiency virus (HIV) infection. The autoimmunity in AIDS is evident by: (1) overproduction of autoantibodies, (2) impaired response of CD4 cells and CD8 cells, (3) failure of clinical trials of HIV vaccines, and (4) therapeutic benefits of immunosuppression following solid organ transplantation and bone marrow transplantation in patients at risk of AIDS. Autoantibodies are generated in response to antigens such as debris and molecules de novo released from dead cells, infectious agents, and catabolic events. Disturbances in metabolic homeostasis occur at the interface of immunodeficiency and autoimmunity in the development of AIDS. Optimal treatments favor therapeutics targeting on the regulation of metabolism to restore immune homeostasis.

Hairy leukoplakia; lessons learned: 30-plus years

Well into the fourth decade of the HIV/AIDS pandemic, we can look back on the early years, the initial discoveries, and the broad sweep of the progress of our understanding of the nature, causes, and significance of the oral lesions seen in those infected with the virus. Prominent among these is oral hairy leukoplakia (HL), a previously unknown lesion of the mouth associated with Epstein-Barr virus (EBV) and initially seen only in people with AIDS, in the then-recognized risk groups, or those shown to be HIV positive. Subsequently, it became clear that the distribution of HL extends well beyond the HIV spectrum. In this brief review, we consider the clinical and histological features of HL, discuss how it was discovered, explore its cause, diagnosis, relationship with AIDS, pathogenesis, significance in EBV biology, options for management, and how it changes with HIV/AIDS therapy.

Oral candidiasis among African human immunodeficiency virus-infected individuals: 10 years of systematic review and meta-analysis from sub-Saharan Africa

Oral candidiasis (OC) is the most common opportunistic fungal infection among immunocompromised individuals. This systematic review and meta-analysis reports on the contribution of non-albicans Candida species in causing OC among human immunodeficiency virus (HIV)-infected individuals in sub-Saharan Africa between 2005 and 2015. Thirteen original research articles on oral Candida infection/colonization among HIV-infected African populations were reviewed. The prevalence of OC ranged from 7.6% to 75.3%. Pseudomembranous candidiasis was found to range from 12.1% to 66.7%. The prevalence of non-albicans Candida species causing OC was 33.5% [95% confidence interval (CI) 30.9–36.39%]. Of 458 non-albicans Candida species detected, C. glabrata (23.8%; 109/458) was the most common, followed by C. tropicalis (22%; 101/458) and C. krusei (10.7%; 49/458). The overall fluconazole resistance was 39.3% (95% CI 34.4–44.1%). Candida albicans was significantly more resistant than non-albicans Candida species to fluconazole (44.7% vs 21.9%; p < 0.001). One-quarter of the cases of OC among HIV-infected individuals in sub-Saharan Africa were due to non-albicans Candida species. Candida albicans isolates were more resistant than the non-albicans Candida species to fluconazole and voriconazole. Strengthening the capacity for fungal diagnosis and antifungal susceptibility testing in sub-Saharan Africa is mandatory in order to track the azole resistance trend.

The Aryl Hydrocarbon Receptor Governs Epithelial Cell Invasion during Oropharyngeal Candidiasis

Oropharyngeal candidiasis (OPC), caused predominantly by Candida albicans, is a prevalent infection in patients with advanced AIDS, defects in Th17 immunity, and head and neck cancer. A characteristic feature of OPC is fungal invasion of the oral epithelial cells. One mechanism by which C. albicans hyphae can invade oral epithelial cells is by expressing the Als3 and Ssa1 invasins that interact with the epidermal growth factor receptor (EGFR) on epithelial cells and stimulate endocytosis of the organism. However, the signaling pathways that function downstream of EGFR and mediate C. albicans endocytosis are poorly defined. Here, we report that C. albicans infection activates the aryl hydrocarbon receptor (AhR), leading to activation of Src family kinases (SFKs), which in turn phosphorylate EGFR and induce endocytosis of the fungus. Furthermore, treatment of oral epithelial cells with interferon gamma inhibits fungal endocytosis by inducing the synthesis of kynurenines, which cause prolonged activation of AhR and SFKs, thereby interfering with C. albicans-induced EGFR signaling. Treatment of both immunosuppressed and immunocompetent mice with an AhR inhibitor decreases phosphorylation of SFKs and EGFR in the oral mucosa, reduces fungal invasion, and lessens the severity of OPC. Thus, our data indicate that AhR plays a central role in governing the pathogenic interactions of C. albicans with oral epithelial cells during OPC and suggest that this receptor is a potential therapeutic target.

OPC is caused predominantly by the fungus C. albicans, which can invade the oral epithelium by several mechanisms. One of these mechanisms is induced endocytosis, which is stimulated when fungal invasins bind to epithelial cell receptors such as EGFR. Receptor binding causes rearrangement of epithelial cell microfilaments, leading to the formation of pseudopods that engulf the fungus and pull it into the epithelial cell. We discovered AhR acts via SFKs to phosphorylate EGFR and induce the endocytosis of C. albicans. Our finding that a small molecule inhibitor of AhR ameliorates OPC in mice suggests that a strategy of targeting host cell signaling pathways that govern epithelial cell endocytosis of C. albicans holds promise as a new approach to preventing or treating OPC.

(A1) Identification of Oral Health Care Needs in Children and Adults, Management of Oral Diseases

The workshop considered five questions reviewing the identification of international oral health care needs of children and adults, and the management of oral diseases in resource-poor countries: (1) What is the role of the dental profession in the management of the HIV-infected individual? (2) Identifying health care needs-What are the epidemiology and disparities of HIV-associated oral lesions in children from different continents? (3) How effective is HIV treatment in controlling oral diseases? (4) Could we develop basic inexpensive oral and dental care protocols for economically deprived HIV-infected patients? and (5) What is the best method of arranging resources to meet the oral health care needs of people with HIV disease? The consensus of the workshop participants was that there is a need to re-target research efforts to non-established market economy countries and prioritize research in these regions to children with HIV disease. It will be important to assess commonalities and variations in oral health needs across geographical and cultural boundaries, and research efforts should be centralized in resource-poor countries to support multi-center longitudinal standardized studies. It is essential that oral health research be integrated into other health care research programs, to make these research priorities and public health initiatives feasible.

Oral Lesions of HIV Disease and HAART in Industrialized Countries

The epidemiology of HIV-related oral disease in industrialized nations has evolved following the initial manifestations described in 1982. Studies from both the Americas and Europe report a decreased frequency of HIV-related oral manifestations of 10–50% following the introduction of HAART (highly active antiretroviral therapy). Evidence suggests that HAART plays an important role in controlling the occurrence of oral candidosis. The effect of HAART on reducing the incidence of oral lesions, other than oral candidosis, does not appear as significant, possibly as a result of low lesion prevalence in industrialized countries. In contrast to other oral manifestations of HIV, an increased prevalence of oral warts in patients on HAART has been reported from the USA and the UK. HIV-related salivary gland disease may show a trend of rising prevalence in the USA and Europe. The re-emergence of HIV-related oral disease may be indicative of failing therapy. A range of orofacial iatrogenic consequences of HAART has been reported, and it is often difficult to distinguish between true HIV-related oral disease manifestations and the adverse effects of HAART. A possible association between an increased risk of oral squamous cell carcinoma and HIV infection has been suggested by at least three epidemiological studies, with reference to the lip and tongue. These substantial and intensive research efforts directed toward enhancing knowledge regarding the orofacial consequences of HIV infection in the industrialized nations require dissemination in the wider health care environment.

High Oral Carriage of Non-albicans Candida spp. among HIV-infected individuals

BACKGROUND

Non-albicans Candida (NAC) spp. in immunocompromised patients are linked to invasive infections with narrow treatment choice. This study aimed at comparing the oral colonization of NAC spp. between HIV and non-HIV infected individuals in Mwanza, Tanzania.

METHOD

Oral rinse of 351 HIV-infected and 639 non-HIV infected individuals were collected between March and July 2015. Phenotypic identifications of Candida spp. was done using Candida Chromogenic agar and confirmed by MALDI-TOF MS.

RESULTS

NAC spp. were detected in 36/351 (10.3%) HIV-infected individuals compared to 28/639 (4.4%) of non-HIV infected individuals; P=0.0003. In HIV infected individuals, commonly isolated NAC spp. were Candida tropicalis, 10(2.8%), C. krusei (Issatschenki orientalis) 9(2.6%) and C. glabrata 8(2.3%). While for non-HIV infected individuals C. dubliniensis 8(1.3%) and C. tropicalis 5(0.9%) were commonly detected. As CD4 count/μl decreases by one unit the risk of being colonized by NAC spp. among HIV infected individuals increases by 1% (OR 1.01, 95% CI; 1.001-1.004, P=0.001).

CONCLUSION

The prevalence of NAC spp. is high among HIV-infected individuals with low CD4 count placing them at higher risk of invasive infections. Further studies to investigate the role of NAC spp. in causing invasive infections among immunocompromised patients are recommended.

Efficacy of nystatin for the treatment of oral candidiasis: a systematic review and meta-analysis

Objective

To systematically review and assess the efficacy, different treatment protocols (formulation, dosage, and duration), and safety of nystatin for treating oral candidiasis.

Methods

Four electronic databases were searched for trials published in English till July 1, 2015. Randomized controlled trials comparing nystatin with other antifungal therapies or a placebo were included. Clinical and/or mycological cure was the outcome evaluation. A meta-analysis or descriptive study on the efficacy, treatment protocols, and safety of nystatin was conducted.

Results

The meta-analysis showed that nystatin pastille was significantly superior to placebo in treating denture stomatitis. Nystatin suspension was not superior to fluconazole in treating oral candidiasis in infants, children, or HIV/AIDS patients. The descriptive investigations showed that administration of nystatin suspension and pastilles in combination for 2 weeks might achieve a higher clinical and mycological cure rate, and using the nystatin pastilles alone might have a higher mycological cure rate, when compared with using nystatin suspensions alone. Nystatin pastilles at a dose of 400,000 IU resulted in a significantly higher mycological cure rate than that administrated at a dose of 200,000 IU. Furthermore, treatment with nystatin pastilles for 4 weeks seemed to have better clinical efficacy than treatment for 2 weeks. Descriptive safety assessment showed that poor taste and gastrointestinal adverse reaction are the most common adverse effects of nystatin.

Conclusion

Nystatin pastille was significantly superior to placebo in treating denture stomatitis, while nystatin suspension was not superior to fluconazole in treating oral candidiasis in infants, children, or HIV/AIDS patients. Indirect evidence from a descriptive study demonstrated that administration of nystatin pastille alone or pastille and suspension in combination is more effective than that of suspension alone; prolonged treatment duration for up to 4 weeks can increase the efficacy of nystatin. More well designed and high quality randomized control studies are needed to confirm these findings.

High Accuracy of Common HIV-Related Oral Disease Diagnoses by Non-Oral Health Specialists in the AIDS Clinical Trial Group

Objective

Many studies include oral HIV-related endpoints that may be diagnosed by non-oral-health specialists (non-OHS) like nurses or physicians. Our objective was to assess the accuracy of clinical diagnoses of HIV-related oral lesions made by non-OHS compared to diagnoses made by OHS.

Methods

A5254, a cross-sectional study conducted by the Oral HIV/AIDS Research Alliance within the AIDS Clinical Trial Group, enrolled HIV-1-infected adults participants from six clinical trial units (CTU) in the US (San Francisco, New York, Chapel Hill, Cleveland, Atlanta) and Haiti. CTU examiners (non-OHS) received standardized training on how to perform an oral examination and make clinical diagnoses of specific oral disease endpoints. Diagnoses by calibrated non-OHS were compared to those made by calibrated OHS, and sensitivity and specificity computed.

Results

Among 324 participants, the majority were black (73%), men (66%), and the median CD4+ cell count 138 cells/mm³. The overall frequency of oral mucosal disease diagnosed by OHS was 43% in US sites, and 90% in Haiti. Oral candidiasis (OC) was detected in 153 (47%) by OHS, with erythematous candidiasis (EC) the most common type (39%) followed by pseudomembranous candidiasis (PC; 26%). The highest prevalence of OC (79%) was among participants in Haiti, and among those with CD4+ cell count ≤ 200 cells/mm³ and HIV-1 RNA > 1000 copies/mL (71%). The sensitivity and specificity of OC diagnoses by non-OHS were 90% and 92% (for EC: 81% and 94%; PC: 82% and 95%). Sensitivity and specificity were also high for KS (87% and 94%, respectively), but sensitivity was < 60% for HL and oral warts in all sites combined. The Candida culture confirmation of OC clinical diagnoses (as defined by ≥ 1 colony forming unit per mL of oral/throat rinse) was ≥ 93% for both PC and EC.

Conclusion

Trained non-OHS showed high accuracy of clinical diagnoses of OC in comparison with OHS, suggesting their usefulness in studies in resource-poor settings, but detection of less common lesions may require OHS.

Antifungal effect of Trachyspermum ammi against susceptible and fluconazole-resistant strains of Candida albicans

OBJECTIVE

Trachyspermum ammi (T. ammi) has been known as having many therapeutic properties and its antimicrobial activity has currently received a renewed interest. This study aimed to verify the effectiveness of T. ammi essential oil to inhibit the growth of Candida albicans (C. albicans) strains isolated from HIV(+) patients with oropharyngeal candidiasis (OPC).

MATERIALS AND METHODS

The essential oil was obtained by hydrodistillation in a Clevenger apparatus and analyzed by gas chromatography. Susceptibility tests were expressed as inhibition zone by the disk diffusion method and minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) by the broth microdilution method.

RESULTS

Thymol (63.4%), p-cymene (19%) and γ-terpinen (16.9%) were found as the most abundant constituents. The disk diffusion results revealed that 67% of oral C. albicans isolates were susceptible, 9% susceptible-dose dependent and 24% resistant to fluconazole. In the broth microdilution method, 68% of isolates were susceptible, 5% susceptible-dose dependent and 27% resistant to fluconazole. The increase in concentration led to a significant reduction in yeasts that were growing in exponential phase. In addition, with increasing in T. ammi oil concentration, the time of remaining cells in lag phase was significantly increased.

CONCLUSION

This study showed that all clinical C. albicans isolates were susceptible to T. ammi essential oil, indicating a significant reduction in the yeast growth in exponential phase.

Role of oral candidiasis in TB and HIV co-infection: AIDS Clinical Trial Group Protocol A5253

OBJECTIVE

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.

METHODS

Protocol A5253 was a cross-sectional study designed to improve the diagnosis of pulmonary TB in HIV-infected adults in high TB prevalence countries. Participants received an oral examination to detect oral candidiasis. We estimated the association between TB disease and oral candidiasis using logistic regression, and sensitivity, specificity and predictive values.

RESULTS

Of 454 participants with TB culture results enrolled in African sites, the median age was 33 years, 71% were female and the median CD4 count was 257 cells/mm(3). Fifty-four (12%) had TB disease; the prevalence of oral candidiasis was significantly higher among TB cases (35%) than among non-TB cases (16%, P < 0.001). The odds of having TB was 2.4 times higher among those with oral candidiasis when controlling for CD4 count and antifungals (95%CI 1.2-4.7, P = 0.01). The sensitivity of oral candidiasis as a predictor of TB was 35% (95%CI 22-48) and the specificity 85% (95%CI 81-88).

CONCLUSION

We found a strong association between oral candidiasis and TB disease, independent of CD4 count, suggesting that in resource-limited settings, oral candidiasis may provide clinical evidence for increased risk of TB and contribute to TB case finding.

Structural basis for heterogeneous phenotype of ERG11 dependent Azole resistance in C.albicans clinical isolates

Correlating antifungal Azole drug resistance and mis-sense mutations of ERG11 has been paradoxical in pathogenic yeast Candida albicans. Amino acid substitutions (single or multiple) are frequent on ERG11, a membrane bound enzyme of Ergosterol biosynthesis pathway. Presence or absence of mutations can not sufficiently predict susceptibility. To analyze role of mis-sense mutations on Azole resistance energetically optimized, structurally validated homology model of wild C.albicans ERG11 using eukaryotic template was generated. A Composite Search Approach is proposed to identify vital residues for interaction at 3D active site. Structural analysis of catalytic groove, dynamics of substrate access channels and proximity of Heme prosthetic group characterized ERG11 active site. Several mis-sense mutations of ERG11 reported in C.albicans clinical isolates were selected through a stringent criterion and modeled. ERG11 mutants subsequently subjected to a four tier comparative biophysical analysis. This study indicates (i) critical interactions occur with residues at anterior part of 3D catalytic groove and substitution of these vital residues alters local geometry causing considerable change in catalytic pocket dimension. (ii) Substitutions of vital residues lead to confirmed resistance in clinical isolates that may be resultant to changed geometry of catalytic pocket. (iii)These substitutions also impart significant energetic changes on C.albicans ERG11 and (iv) include detectable dynamic fluctuations on the mutants. (v)Mis-sense mutations on the vital residues of the active site and at the vicinity of Heme prosthetic group are less frequent compared to rest of the enzyme. This large scale mutational study can aid to characterize the mutants in clinical isolates.

Levels of HIV-1 in subgingival biofilm of HIV-infected patients

AIM

The aims of the current study were to compare the levels of HIV-1 in the subgingival biofilm (SHVL) between detectable and undetectable plasmatic HIV-1 viral load (PHVL) in HIV-infected patients as well as to determine the association of SHVL with PHVL and clinical periodontal parameters.

MATERIAL AND METHODS

Forty-one HIV-infected individuals were divided into two groups: detectable (21) and undetectable (20) PHVL. Subgingival biofilm samples were obtained for detection and quantification of HIV-1 by real-time RT-PCR. To estimate the effect of co-variables on the outcome undetectable SHVL, the Generalized Estimation Equation (GEE) was employed.

RESULTS

Detectable SHVL was observed only in the detectable PHVL group and the detection of the HIV-1 was observed in 40% of these individuals. In the bivariate analysis between co-variables from the individual level and the outcome SHVL, significant difference was observed only for the CD4+ T lymphocytes levels (p = 0.017). The multiple logistic model demonstrated that only CD4+ T lymphocytes levels had a significant effect on the outcome undetectable SHVL [OR 8.85 (CI 3.6-9.2), p = 0.002].

CONCLUSION

HIV-1 can be detected and quantified in the subgingival biofilm of HIV-infected individuals, but these findings are not associated with PHVL and periodontal clinical parameters.

Role of autophagy genetic variants for the risk of Candida infections

Candida albicans can cause candidemia in neutropenic and critically ill patients and oropharyngeal candidiasis in human immunodeficiency virus (HIV)-positive patients with low CD4(+) counts. Because all patients at risk do not develop Candida infections, it is possible that a patient's genetic background might play a role in his or her susceptibility to infection. Autophagy mediates pathogen clearance and modulation of inflammation. Our aim was to assess the effect of genetic variations in the ATG16L1 and IRGM autophagy genes on the susceptibility of patients with candidemia and oropharyngeal candidiasis. We assessed genetic variations in the ATG16L1 and IRGM genes in a cohort of candidemia patients of both African and European origin. In addition, we evaluated the effect of these polymorphisms on the susceptibility to oropharyngeal candidiasis of an HIV-positive cohort from Tanzania. Functional studies have been performed to assess the effect of the ATG16L1 and IRGM genetic variants on both in vitro and in vivo cytokine production. The results indicate that ATG16L1 variants modulate production of tumor necrosis factor-alpha, but not other cytokines, while no effects were seen in the presence of IRGM polymorphisms. In addition, no significant associations between the single-nucleotide polymorphisms in the ATG16L1 and IRGM genetic variants and the incidence of candidemia or oropharyngeal candidiasis were identified. Despite moderate effects on the modulation of proinflammatory cytokine production, genetic variation in the autophagy genes ATG16L1 and IRGM has a minor impact on the susceptibility to both mucosal and systemic Candida infections.

UPC2 is universally essential for azole antifungal resistance in Candida albicans

In Candida albicans, the transcription factor Upc2 is central to the regulation of ergosterol biosynthesis. UPC2-activating mutations contribute to azole resistance, whereas disruption increases azole susceptibility. In the present study, we investigated the relationship of UPC2 to fluconazole susceptibility, particularly in azole-resistant strains. In addition to the reduced fluconazole MIC previously observed with UPC2 disruption, we observed a lower minimum fungicidal concentration (MFC) for a upc2Δ/Δ mutant than for its azole-susceptible parent, SC5314. Moreover, the upc2Δ/Δ mutant was unable to grow on a solid medium containing 10 μg/ml fluconazole and exhibited increased susceptibility and a clear zone of inhibition by Etest. Time-kill analysis showed higher fungistatic activity against the upc2Δ/Δ mutant than against SC5314. UPC2 disruption in strains carrying specific resistance mutations also resulted in reduced MICs and MFCs. UPC2 disruption in a highly azole resistant clinical isolate containing multiple resistance mechanisms likewise resulted in a reduced MIC and MFC. This mutant was unable to grow on a solid medium containing 10 μg/ml fluconazole and exhibited increased susceptibility and a clear zone of inhibition by Etest. Time-kill analysis showed increased fungistatic activity against the upc2Δ/Δ mutant in the resistant background. Microarray analysis showed attenuated induction by fluconazole of genes involved in sterol biosynthesis, iron transport, or iron homeostasis in the absence of UPC2. Taken together, these data demonstrate that the UPC2 transcriptional network is universally essential for azole resistance in C. albicans and represents an attractive target for enhancing azole antifungal activity.

Asymptomatic oral yeast carriage and antifungal susceptibility profile of HIV-infected patients in Kunming, Yunnan Province of China

BACKGROUND

Oral Candida colonization and its relation with predisposing factors in HIV-infected patients have received wide concerns during recent decades. In this study, we investigated asymptomatic oral Candida carriage rate, species distribution and antifungal susceptibility of 604 HIV-infected patients and 851 healthy individuals in Kunming, Yunnan Province of China.

METHODS

Mucosal swab sampling was taken from each subject and CHROMagar Candida agar medium and API 20C AUX system were used to identify yeast isolates. In vitro antifungal susceptibility was tested by the broth microdilution method according to the M27-A2 document of the Clinical and Laboratory Standard Institute (CLSI).

RESULTS

The oral yeast colonization rate in HIV-infected patients (49.5%) was higher than that of healthy subjects (20.7%). Candida albicans constituted the most frequent species, accounting for 82.2% of yeast isolates. The remaining species were composed of C. glabrata, C. parapsilosis, C. krusei, C. tropicalis, C. rugosa, C. norvegensis, Pichia ohmeri and Saccharomyces cerevisiae. In HIV-infected patients, asymptomatic oral yeast colonization was associated with low CD4 cell count (<200 cells/mm3) and lack of highly active antiretroviral therapy (HAART). Different Candida species isolated from our samples presented different susceptibility to voriconazole, fluconazole and itraconazole. Amphotericin B had the best inhibiting effect for all isolates.

CONCLUSION

Oral yeast colonization in Han Chinese patients with HIV from Kunming had common and unique features and was associated with CD4 cell number and HARRT. Amphotericin B should be used with first priority in controlling Candida infection in Han Chinese patients from Kunming. Our results provide first hand information on monitoring oral yeasts colonization in HIV-infected patients from Kunming, China.

Factors associated with specific clinical forms of oral candidiasis in HIV-infected Brazilian adults

OBJECTIVE

This study assesses the association among factors related with specific clinical forms of oral candidiasis (OC) in HIV-infected Brazilian adults.

DESIGN

This study was conducted with 590 HIV-infected adults from 1997 to 2004. The OC diagnosis was based in accordance with the EC-Clearinghouse classification. Multivariate logistic regression analyses were performed to measure the association between HAART and OC, with pseudomembranous [PC], erythematous [EC], and angular cheilitis [AC]) adjusted for HIV-related diseases, smoking, alcohol consumption, injecting and non-injecting drug use.

RESULTS

Two hundred and eighteen (37.0%) individuals were undergoing HAART. The prevalence of PC, EC and AC was 21.2%, 15.7% and 8.8%, respectively. Approximately 64% of the individuals with PC and EC, and 76.5% with AC had absolute CD4 levels ≤200cells/mm(3). The results of the multivariate analysis showed that subjects not undergoing HAART had a significantly higher odds ratio for PC [OR 3.67 (95% CI: 1.97-6.80)] and EC [OR 1.88 (95% CI: 1.04-3.39)], and AC [OR 4.56 (95% CI: 1.58-13.19)]. In addition, smoking [OR 2.58 (95% CI: 1.43-4.68)] and pneumocystis pneumonia [OR 1.92 (95% CI: 1.07-3.42)] were associated with PC, while high alcohol consumption [OR 3.40 (95% CI: 1.13-10.18)] and cytomegalovirus infection [OR 2.34 (95% CI: 1.06-5.15)] were associated with EC.

CONCLUSION

The data indicates that the odds of having all clinical forms of OC are higher in HIV-infected adults not receiving HAART.

Proteomic analysis of Mrr1p- and Tac1p-associated differential protein expression in azole-resistant clinical isolates of Candida albicans

Azole resistance in Candida albicans is frequently caused by the overexpression of multi-drug efflux pump genes MDR1, CDR1, and CDR2 due to gain-of-function mutations in the zinc cluster transcription factors Mrr1p and Tac1p. In this study, we performed a comparative proteomic analysis to identify proteins whose expression level is influenced by these transcription factors. Both 2-DE and PMF were used to examine the expression profiles of six pairs of matched C. albicans isolates carrying gain-of-function mutations in either MRR1 or TAC1 resulting in the overexpression of either MDR1 or CDR1 and CDR2. Using this approach, 17 differentially expressed proteins were identified in the MDR1-overexpressing isolates, while 14 were identified in the isolates that overexpress CDR1 and CDR2. Furthermore, we found that the expression of many of these proteins was increased in a wild-type strain of C. albicans after the introduction of a gain-of-function allele of MRR1 or TAC1. Moreover, disruption of MRR1 and TAC1 in isolates carrying gain-of-function mutations resulted in decreased expression of these proteins, confirming their regulation by Mrr1p or Tac1p. Several proteins involved in heat shock and carbohydrate metabolism were differentially expressed in all clinical isolate sets, but these proteins were not dependent upon either Tac1p or Mrr1p.

Gender differences in oral lesions among persons with HIV disease in Southern India

INTRODUCTION

In India, it is estimated that 2.5 million people are currently living with Human Immunodeficiency virus infection (HIV) of which one million are women. Given the occurrence of oral lesions in our population, we studied the patter of these lesions with respect to the role played by gender.

MATERIALS AND METHODS

3729 consecutive patients seen over a period of 10 years (from 1998 to 2008) attending the YRG CARE (Center for AIDS Research and Education), at Chennai, India constituted the study group. The oral lesions were diagnosed and the findings were entered into a database and analysed using the SPSS package SPSS11.

RESULTS

3724 adult patients (71% males 29% females) were recruited in this study. 95% and 92% of males and females respectively acquired the infection through the heterosexual route. 69% of them presented with at least one oral lesion. There was a significant difference in the occurrence of oral candidiasis (OC) (18.8% males 10.3% females, P = 0.00) and oral hairy leukoplakia (OHL) (1.2% males 0.4% females, P = 0.023) between gender. The mean CD4 counts in males (n = 1908) was 284.48 ± 222.45 and in females (n = 1087) it was 394.51 ± 274.56. Males had 2.2 times higher risk of getting OC, 3.1 times higher risk of OHL and over all males had 1.58 times of having any oral lesion compared to females. Multivariate logistic regression that the odds of having OC (OR = 1.7, 95%CI 1.2-2.2, P = 0.001) and OHL (OR = 3.1, 95%CI 1.1-8.9; P = 0.03) were significantly higher for males than for females after controlling for duration of being HIV positive, CD4 count and HAART. 1412 patients had their spouses HIV status also as HIV positive and 769 patients had their spouse HIV status as negative. 858 patients were on HARRT (627 males and 231 females) The partial correlation analysis, done between gender and CD4 counts, when controlling for HAART was r = 0.2028 (P = 0.00).

CONCLUSION

Our study confirms that males had a higher risk of oral lesions, especially OC and OHL, than females. The females in this study had a significantly higher mean CD4 counts than males. This different immunological status of the females compared to males should be taken in to consideration in the evaluation and management of HIV positive patients in our country.

Gain-of-function mutations in UPC2 are a frequent cause of ERG11 upregulation in azole-resistant clinical isolates of Candida albicans

In Candida albicans, Upc2 is a zinc-cluster transcription factor that targets genes, including those of the ergosterol biosynthesis pathway. To date, three documented UPC2 gain-of-function (GOF) mutations have been recovered from fluconazole-resistant clinical isolates that contribute to an increase in ERG11 expression and decreased fluconazole susceptibility. In a group of 63 isolates with reduced susceptibility to fluconazole, we found that 47 overexpressed ERG11 by at least 2-fold over the average expression levels in 3 unrelated fluconazole-susceptible strains. Of those 47 isolates, 29 contained a mutation in UPC2, whereas the remaining 18 isolates did not. Among the isolates containing mutations in UPC2, we recovered eight distinct mutations resulting in putative single amino acid substitutions: G648D, G648S, A643T, A643V, Y642F, G304R, A646V, and W478C. Seven of these resulted in increased ERG11 expression, increased cellular ergosterol, and decreased susceptibility to fluconazole compared to the results for the wild-type strain. Genome-wide transcriptional analysis was performed for the four strongest Upc2 amino acid substitutions (A643V, G648D, G648S, and Y642F). Genes commonly upregulated by all four mutations included those involved in ergosterol biosynthesis, in oxidoreductase activity, the major facilitator efflux pump encoded by the MDR1 gene, and the uncharacterized ATP binding cassette transporter CDR11. These findings demonstrate that gain-of-function mutations in UPC2 are more prevalent among clinical isolates than previously thought and make a significant contribution to azole antifungal resistance, but the findings do not account for ERG11 overexpression in all such isolates of C. albicans.

A Comparative Study of Oral Candidal Carriage and Its Association with CD4 Count between HIV-Positive and Healthy Individuals

Aims and Objectives:

To correlate asymptomatic oral candidal carriage in HIV-positive patients and normal individuals and determine its association with CD4 count.

Material and Methods:

Forty HIV-positive patients and forty healthy individuals were included in this study. Saliva from both groups was collected by the spitting method. The saliva from each individual was incubated aerobically on Sabouraud Dextrose agar with antibiotics at 37°C. The germ tube method was used for differentiation of candidal species, whether the Candida albicans or non- Candida albicans. Surface count method was used to count the number of colonies of candida species. Data were analyzed by chi square and Mann-Whitney test.

Results:

Oral candidal carriage was found in 22 out of 40 (55%) HIV-positive patients. In healthy volunteers, oral candidal carriage was found in 6 out of 40 (15%) individuals ( p value = 0.0002), which is significantly higher. Similarly, density carriage in the HIV-positive patients was found to be significantly higher than that in the HIV-negative group ( p value = 0.002). However, oral yeast carriage was not associated with CD4 count (correlation coefficient r = −0.087).

Conclusion:

Within the limits of the study, we concluded oral candidal carriage rate and density carriage higher in HIV-positive patients than in healthy individuals.

Overview of the oral HIV/AIDS Research Alliance Program

The Oral HIV/AIDS Research Alliance is part of the AIDS Clinical Trials Group, the largest HIV clinical trial organization in the world, and it is funded by the National Institute of Dental and Craniofacial Research, in collaboration with the National Institute of Allergy and Infectious Diseases. The alliance's main objective is to investigate the oral complications associated with HIV/AIDS as the epidemic is evolving-in particular, the effects of potent antiretrovirals on the development of oral mucosal lesions and associated fungal and viral pathogens. Furthermore, oral fluids are being explored for their potential monitoring and diagnostic role with respect to HIV disease and coinfections. This article presents an overview of the alliance, its scientific agenda, and an outline of the novel interventional and noninterventional clinical studies ongoing and developing within the AIDS Clinical Trials Group infrastructure in the United States and internationally.

Management of oropharyngeal and esophageal candidiasis in patients with HIV infection

Mucocutaneous candidiasis is frequently one of the first signs of HIV infection. Over 90% of patients with AIDS will develop oropharyngeal candidiasis at some time during their illness. Although numerous antifungal agents have been developed, azoles, both topical (clotrimazole) and systemic (fluconazole, itraconazole, voriconazole and posaconazole), have replaced older topical antifungals (gentian violet and nystatin) in the management of oropharyngeal candidiasis in these patients. The systemic azoles are generally safe and effective agents in HIV-infected patients with oropharyngeal candidiasis. A constant concern in these patients are relapses, which depend on the degree of immunosuppression and are commonly encountered after topical therapy rather than with systemic azole therapy. In patients with fluconazole-refractory mucosal candidiasis, treatment options now include itraconazole solution, voriconazole, posaconazole and the newer echinocandins (caspofungin, micafungin and anidulafungin). The objective of this article is to review the epidemiology, diagnosis and newer management modalities of oropharyngeal and esophageal candidiasis in HIV-infected individuals.

Optimal management of oropharyngeal and esophageal candidiasis in patients living with HIV infection

Mucocutaneous candidiasis is frequently one of the first signs of human immunodeficiency virus (HIV) infection. Over 90% of patients with AIDS will develop oropharyngeal candidiasis (OPC) at some time during their illness. Although numerous antifungal agents are available, azoles, both topical (clotrimazole) and systemic (fluconazole, itraconazole, voriconazole, posaconazole) have replaced older topical antifungals (gentian violet and nystatin) in the management of oropharyngeal candidiasis in these patients. The systemic azoles, are generally safe and effective agents in HIV-infected patients with oropharyngeal candidiasis. A constant concern in these patients is relapse, which is dependent on the degree of immunosuppression commonly seen after topical therapy, rather than with systemic azole therapy. Candida esophagitis (CE) is also an important concern since it occurs in more than 10% of patients with AIDS and can lead to a decrease in oral intake and associated weight loss. Fluconazole has become the most widely used antifungal in the management of mucosal candidiasis. However, itraconazole and posaconazole have similar clinical response rates as fluconazole and are also effective alternative agents. In patients with fluconazole-refractory mucosal candidiasis, treatment options now include itraconazole solution, voriconazole, posaconazole, and the newer echinocandins (caspofungin, micafungin, and anidulafungin).

The Oral HIV/AIDS Research Alliance: updated case definitions of oral disease endpoints

The Oral HIV/AIDS Research Alliance (OHARA) is part of the AIDS Clinical Trials Group (ACTG), the largest HIV clinical trials organization in the world. Its main objective is to investigate oral complications associated with HIV/AIDS as the epidemic is evolving, in particular, the effects of antiretrovirals on oral mucosal lesion development and associated fungal and viral pathogens. The OHARA infrastructure comprises: the Epidemiologic Research Unit (at the University of California San Francisco), the Medical Mycology Unit (at Case Western Reserve University) and the Virology/Specimen Banking Unit (at the University of North Carolina). The team includes dentists, physicians, virologists, mycologists, immunologists, epidemiologists and statisticians. Observational studies and clinical trials are being implemented at ACTG-affiliated sites in the US and resource-poor countries. Many studies have shared end-points, which include oral diseases known to be associated with HIV/AIDS measured by trained and calibrated ACTG study nurses. In preparation for future protocols, we have updated existing diagnostic criteria of the oral manifestations of HIV published in 1992 and 1993. The proposed case definitions are designed to be used in large-scale epidemiologic studies and clinical trials, in both US and resource-poor settings, where diagnoses may be made by non-dental healthcare providers. The objective of this article is to present updated case definitions for HIV-related oral diseases that will be used to measure standardized clinical end-points in OHARA studies, and that can be used by any investigator outside of OHARA/ACTG conducting clinical research that pertains to these end-points.

Prevalence of oral disease among adults with primary HIV infection

OBJECTIVE

To explore the type and prevalence of oral mucosal lesions among adults with primary HIV infection (PHI) compared with HIV-negative adults at high risk for HIV disease, and in relation to HIV viral load.

METHODS

We conducted standardized oral examinations to identify specific oral mucosal lesions among adults with PHI, both pre-seroconversion and post- seroconversion-recently infected, compared with HIV-negative adults. We compared the group with oral lesions to those without oral lesions with respect to HIV-RNA load and CD4 + T-cell count.

RESULTS

Among 115 adults (predominantly men), pseudomembranous candidiasis was the most common oral lesion among those with PHI, and was found in 4% of the 23 participants in pre-seroconversion and in 9% of 69 participants with post-seroconversion recent infection, compared with none found among 23 HIV negatives. Among those with PHI, the median viral load was higher and the median CD4 + T-cell count lower among the 15 participants with an oral lesion of any type than among the 77 participants without oral lesions (P = 0.02 and 0.04, respectively).

CONCLUSION

This finding suggests that individuals with PHI who have oral lesions may be more likely to transmit HIV because of their higher viral load.

Species distribution and in vitro antifungal susceptibility of oral yeast isolates from Tanzanian HIV-infected patients with primary and recurrent oropharyngeal candidiasis

Background

In Tanzania, little is known on the species distribution and antifungal susceptibility profiles of yeast isolates from HIV-infected patients with primary and recurrent oropharyngeal candidiasis.

Methods

A total of 296 clinical oral yeasts were isolated from 292 HIV-infected patients with oropharyngeal candidiasis at the Muhimbili National Hospital, Dar es Salaam, Tanzania. Identification of the yeasts was performed using standard phenotypic methods. Antifungal susceptibility to fluconazole, itraconazole, miconazole, clotrimazole, amphotericin B and nystatin was assessed using a broth microdilution format according to the guidelines of the Clinical and Laboratory Standard Institute (CLSI; M27-A2).

Results

Candida albicans was the most frequently isolated species from 250 (84.5%) patients followed by C. glabrata from 20 (6.8%) patients, and C. krusei from 10 (3.4%) patients. There was no observed significant difference in species distribution between patients with primary and recurrent oropharyngeal candidiasis, but isolates cultured from patients previously treated were significantly less susceptible to the azole compounds compared to those cultured from antifungal naïve patients.

Conclusion

C. albicans was the most frequently isolated species from patients with oropharyngeal candidiasis. Oral yeast isolates from Tanzania had high level susceptibility to the antifungal agents tested. Recurrent oropharyngeal candidiasis and previous antifungal therapy significantly correlated with reduced susceptibility to azoles antifungal agents.

Oral candidiasis as a marker of HIV disease progression among Zimbabwean women

OBJECTIVES

To estimate oral disease prevalence among Zimbabwean women by HIV serostatus and CD4 cell count and to assess accuracy of oral disease diagnoses made by nurses as compared with an oral surgeon.

METHODS

Standardized oral mucosa examinations were performed by trained nurse-examiners and by an oral surgeon among women recruited in Harare, Zimbabwe.

RESULTS

A total of 461 women (320 HIV-infected, 141 uninfected) were seen by nurses and an oral surgeon within a 2-week period. Oral candidiasis (OC) was the most common lesion diagnosed in nearly one quarter of HIV-infected women, whereas hairy leukoplakia and Kaposi sarcoma were found in <3%. The prevalence of OC diagnosed by nurses or the surgeon was significantly higher among women with a CD4 count <200 cells/mm than in women with a CD4 count from 200 to 499 cells/mm3 or a CD4 count >499 cells/mm3. The sensitivity of nurse examinations compared with examinations by the oral surgeon among HIV-infected women for the diagnosis of OC was 73%, the specificity was 95%, and the kappa-statistic was 0.71.

CONCLUSIONS

OC was the most common lesion in HIV-infected women and was strongly associated with a low CD4 cell count. Interexaminer agreement was good for the diagnosis of OC among HIV-infected women. This study suggests that OC may play a role, in combination with other clinical indicators as a marker of disease progression in resource-poor settings.

Antifungal activity of the plant Dodonaea viscosa var. angustifolia on Candida albicans from HIV-infected patients

was to determine the minimum inhibitory concentration (MIC) and the time taken by Dodonaea viscosa var. angustifolia (PLE) a South African medicinal plant, chlorhexidine gluconate (CHX) and triclosan (TRN) to kill Candida albicans. 41 strains of Candida albicans were investigated, 20 from HIV-positive patients, 20 from HIV-negative subjects and Candida albicans ATCC 90028. The MICs of an acetone extract of PLE, CHX and TRN were measured using a microtitre double dilution technique, and the time taken to kill 99.5% of the strains was determined. The MICs of PLE, CHX and TRN were 6.25-25, 0.008-0.16 and 0.0022-0.009 mg/ml, respectively. PLE killed all the test strains within 30s and CHX 40% of the isolates from HIV-positive patients and 20% of strains from HIV-negative subjects in 1 min. During the same time TRN killed 55% and 35% of isolates from HIV-positive and HIV-negative patients. Dodonaea viscosa var. angustifolia has antifungal properties and is more effective than commercially available mouthrinses.

A gain-of-function mutation in the transcription factor Upc2p causes upregulation of ergosterol biosynthesis genes and increased fluconazole resistance in a clinical Candida albicans isolate

In the pathogenic yeast Candida albicans, the zinc cluster transcription factor Upc2p has been shown to regulate the expression of ERG11 and other genes involved in ergosterol biosynthesis upon exposure to azole antifungals. ERG11 encodes lanosterol demethylase, the target enzyme of this antifungal class. Overexpression of UPC2 reduces azole susceptibility, whereas its disruption results in hypersusceptibility to azoles and reduced accumulation of exogenous sterols. Overexpression of ERG11 leads to the increased production of lanosterol demethylase, which contributes to azole resistance in clinical isolates of C. albicans, but the mechanism for this has yet to be determined. Using genome-wide gene expression profiling, we found UPC2 and other genes involved in ergosterol biosynthesis to be coordinately upregulated with ERG11 in a fluconazole-resistant clinical isolate compared with a matched susceptible isolate from the same patient. Sequence analysis of the UPC2 alleles of these isolates revealed that the resistant isolate contained a single-nucleotide substitution in one UPC2 allele that resulted in a G648D exchange in the encoded protein. Introduction of the mutated allele into a drug-susceptible strain resulted in constitutive upregulation of ERG11 and increased resistance to fluconazole. By comparing the gene expression profiles of the fluconazole-resistant isolate and of strains carrying wild-type and mutated UPC2 alleles, we identified target genes that are controlled by Upc2p. Here we show for the first time that a gain-of-function mutation in UPC2 leads to the increased expression of ERG11 and imparts resistance to fluconazole in clinical isolates of C. albicans.

EBV detection in HIV-related oral plasmablastic lymphoma

OBJECTIVES

Plasmablastic lymphoma (PBL) of the oral cavity is an aggressive neoplasm derived from B cell, considered to be the second more common among human immunodeficiency virus (HIV)-associated malignancies. As Epstein-Barr virus (EBV) infection has been associated with this neoplasm, the aim of the present study was to assess the presence of EBV in 11 cases of oral HIV-related PBL and investigate the controversial issue of the presence of Human herpesvirus-8 (HHV-8) in these tumors.

METHODS

DNA was extracted from nine cases of HIV-associated oral lymphomas, diagnosed as PBL, and genomic material was amplified by polymerase chain reaction to verify the presence of EBV. In situ hybridization (ISH) for EBV was performed in five cases. Immunohistochemical analysis was conducted to confirm previous diagnosis and verify HHV-8 infection.

RESULTS

The 11 cases had diagnosis confirmed by immunohistochemical analysis. Only nine cases presented an adequate amount of DNA for analysis, and EBV was detected in seven of them. The five cases tested for EBV viral infection by ISH showed positive signals. All 11 cases were negative for HHV-8.

CONCLUSION

The presence of EBV in all cases studied favors a direct role of this virus in the development of HIV-related PBL, and this finding could be considered when dealing with HIV patients.

Genome-wide expression and location analyses of the Candida albicans Tac1p regulon

A major mechanism of azole resistance in Candida albicans is overexpression of the genes encoding the ATP binding cassette transporters Cdr1p and Cdr2p due to gain-of-function mutations in Tac1p, a transcription factor of the zinc cluster family. To identify the Tac1p regulon, we analyzed four matched sets of clinical isolates representing the development of CDR1- and CDR2-mediated azole resistance by using gene expression profiling. We identified 31 genes that were consistently up-regulated with CDR1 and CDR2, including TAC1 itself, and 12 consistently down-regulated genes. When a resistant strain deleted for TAC1 was examined similarly, expression of almost all of these genes returned to levels similar to those in the matched azole-susceptible isolate. Using genome-wide location (ChIP-chip) analysis (a procedure combining chromatin immunoprecipitation with hybridization to DNA intergenic microarrays), we found 37 genes whose promoters were bound by Tac1p in vivo, including CDR1 and CDR2. Sequence analysis identified nine new genes whose promoters contain the previously reported Tac1p drug-responsive element (CGGN(4)CGG), including TAC1. In total, there were eight genes whose expression was modulated in the four azole-resistant clinical isolates in a TAC1-dependent manner and whose promoters were bound by Tac1p, qualifying them as direct Tac1p targets: CDR1, CDR2, GPX1 (putative glutathione peroxidase), LCB4 (putative sphingosine kinase), RTA3 (putative phospholipid flippase), and orf19.1887 (putative lipase), as well as IFU5 and orf19.4898 of unknown function. Our results show that Tac1p binds under nonactivating conditions to the promoters of its targets, including to its own promoter. They also suggest roles for Tac1p in regulating lipid metabolism (mobilization and trafficking) and oxidative stress response in C. albicans.