Candidiasis In HIV-infected Patients Research Articles

Oropharyngeal candidiasis in HIV-infected patients under treatment with protease inhibitors

<h2>Abstract</h2><h3>Objective</h3> Oropharyngeal candidiasis decreased when protease inhibitors were included with other antiretrovirals to treat HIV infection. We tested oral yeast isolates of Brazilian HIV-infected individuals receiving antiretroviral therapy for protease secretion and susceptibility to ritonavir and some antifungals. <h3>Study design</h3> We collected oral samples and identified yeasts from 19 HIV-infected patients receiving highly active antiretroviral therapy (HAART) and suspected of having oral candidiasis. Ritonavir and its excipients' effects on the isolated yeasts were tested for protease secretion by Rüchel's technique. The yeasts' susceptibility to amphotericin B (AnB), fluorocitosine (5FC), fluconazole (FZL), ketoconazole (KZL), and itraconazole (IZL) was determined by E-test (AB Biodisk). Chi-squared test determined the statistical differences. <h3>Results</h3> Twenty-five different positive isolates were obtained. Sixty-eight percent were <i>C. albicans</i>. Other isolates included <i>C. famata</i> (16%), <i>C. glabr</i>ata (4%), <i>C. tropicalis</i> (4%), <i>T. capitatum</i> (4%), and 1 isolate not identified. High protease secretion was observed for most of the isolates (20/25). Ritonavir only altered enzyme secretion in 6/20 of the protease-secreting isolates. All isolates were highly sensitive to both AnB and 5FC. Antifungal activity did not change when ritonavir was added to the culture media. Some isolates were highly resistant to studied antifungals (52.2% KZL, 30.4% FZL, and 26% IZL). Resistance significantly decreased when ritonavir was added to the medium with KZL and IZL (<i>P</i> < .5 by chi-squared). A trend to decreased resistance was also observed with FZL but the results were not statistically significant. <h3>Conclusion</h3> <i>Candida</i> continues to be the most prevalent fungus in the oral cavity. Although oral candidal isolates secrete protease, ritonavir does not inhibit all protease-secreting oral yeast isolates. There seems to be a synergistic effect between ritonavir and oral antifungals against fungal resistance.

Azole resistance in Candida spp

The emergence of azole-resistant Candida spp. is a significant problem after long-term treatment of recurrent oropharyngeal candidiasis in HIV-infected patients. Several mechanisms can cause this resistance. An important mechanism of azole resistance is reduced intracellular accumulation of the drug. Among the multidrug efflux transporters, ABC transporters and the major facilitator superfamily are reported to cause the resistance. Erg11p, sterol C14 alfa-demethylase, is a target of azole derivatives. It was reported that ERG11 over-expression had only a modest effect on the development of azole resistance. However, mutations in the ERG11 gene can cause the resistance, probably by reducing binding of azole to the target enzyme. We sequenced the ERG11 gene in a high-level azole resistant C. albicans strain, Darlington, and found that two amino acid substitutions, Y132H and I471T, had been encoded in the Darlington ERG11 gene. To assess the significance of these substitutions, we replaced one of the two copies of ERG11 gene in anazole-susceptible strain of C. albicans with a copy of the Darlington ERG11 and this resulted in a modest increase in azole resistance. Furthermore, to estimate the effect of Y132H and I471T individually, ERG11 genes with either or both mutations were expressed in S. cerevisiae. The I471T substitution, not previously described, conferred azole resistance when overexpressed alone and increased this resistance when added to the Y132H substitution. Alterations in the sterol biosynthetic pathway are another resistance mechanism. Inhibition of 14 alfa-demethylase by azole results not only in ergosterol depletion but also in accumulation of methylated sterol 14 alfa-methylergosta-8, 22(28)-dien-3 beta, 6 alfa-diol. We deleted the ERG3 gene, which encodes a sterol 5, 6-desaturase, in C. albicans, and the deletion resulted in reduced susceptibility of the mutant to azoles.Sterol analysis revealed that erg3 mutant lost both ergosterol and diol when cultured with fluconazole.

Susceptibility of Candida dubliniensis to salivary histatin 3.

Candida dubliniensis is a recently described Candida species associated with oral candidiasis in human immunodeficiency virus (HIV)-infected patients and patients with AIDS. The majority of C. dubliniensis clinical isolates tested to date are susceptible to the commonly used antifungal drugs, including fluconazole, ketoconazole, itraconazole, and amphotericin B. However, the appearance of fluconazole-resistant C. dubliniensis strains in this patient group is increasing. Histatins are a family of basic histidine-rich proteins present in human saliva which have therapeutic potential in the treatment of oral candidiasis. The mechanism of action of histatin is distinct from that of commonly used azole and polyene drugs. Characterization of the antifungal activity of histatin has mainly been carried out using C. albicans but it is also effective in killing C. glabrata and C. krusei. Here we report that C. dubliniensis is also susceptible to killing by histatin 3. The concentration of histatin 3 giving 50% killing (the IC(50) value) ranged from 0.043 to 0.196 mg/ml among different strains of C. dubliniensis. The least-susceptible C. dubliniensis strain, P9224, was found to internalize histatin at a lower rate than the C. albicans reference strain CA132A. The dissociation constant (K(d)) for the least-susceptible strain (C. dubliniensis 9224) was ninefold higher than that for the C. albicans reference strain. These results suggest that histatin 3 may have potential as an effective antifungal agent, particularly in the treatment of oral candidiasis in HIV-infected patients and patients with AIDS in which resistance to the commonly used antifungal drug fluconazole has emerged.

Candidíase oral como marcador de prognóstico em pacientes portadores do HIV

Introdução: A candidíase oral é uma das doenças oportunistas mais fortemente associadas à infecção pelo Vírus da Imunodeficiência Humana (HIV). Vários relatos epidemiológicos enfatizam a prevalência da candidíase em pacientes HIV positivos e ressaltam a sua importância como marcador da progressão da doença e preditivo para o aumento da imunodepressão. Objetivo: Verificar as alterações estomatológicas em pacientes portadores do HIV tratados no Hospital Heliópolis - São Paulo, Brasil e comparar com a literatura. Forma de Estudo: Retrospectivo clínico não-randomizado. Casuística e Método: Foram analisados 431 pacientes HIV+/AIDS (298 homens e 133 mulheres) no Hospital Heliópolis - São Paulo, Brasil, no período de 1995 a 2001. Resultados: A idade média mais comum foi dos 31 aos 40 anos (47,10%); a via de contágio mais comum foi a sexual (71,26%). Dentre as patologias, a candidíase apresentou maior prevalência (29,69%), seguida pela gengivite (16,70%) e queilite angular (14,15%). Conclusões: Concluímos que o exame oral e o diagnóstico precoce da candidíase em pacientes infectados pelo HIV são fundamentais para o tratamento imediato, melhorando a sua qualidade de vida, uma vez que a candidíase é uma lesão bucal muito freqüente nesta população.

CD4 lymphocyte percentage vs CD4 lymphocyte count as an immunological marker of oral candidiasis in HIV-infected patients

CD4 lymphocyte percentage vs CD4 lymphocyte count as an immunological marker of oral candidiasis in HIV-infected patients

Clinical Perspective Oropharyngeal Candidiasis in Patients with HIV: Suggested Guidelines for Therapy

The high frequency of oropharyngeal candidiasis in immunocompromised patients has led many institutions to develop protocols to guide the use of antifungal agents in the treatment of this opportunistic infection. However, few specific recommendations have been made for directing the management of oropharyngeal candidiasis in patients infected with HIV. To meet this need, a panel of experts representing a variety of disciplines met to formulate a consensus and devise a treatment strategy for clinical application. Among other recommendations, the algorithm calls for use of a topical agent for the treatment of initial and recurring oropharyngeal candidiasis in HIV-infected patients, provided there is no esophageal involvement, patients' CD4+ lymphocyte cell count is >50 cells/mm3, and they are currently receiving or expected to receive effective antiretroviral treatment. For episodes of oropharyngeal candidiasis with concurrent esophageal involvement or where patients have a CD4+ cell count of <50 cells/mm3, are not receiving or anticipating highly active antiretroviral therapy (HAART), and have a high viral load, the algorithm suggests a systemic oral azole as the more appropriate treatment choice. Acute treatment of all oropharyngeal candidiasis episodes is preferred. Chronic suppressive antifungal treatment is to be avoided in recognition of the potential for the development of drug-resistant infection.

Frequency of oropharyngeal candidiasis in HIV-infected patients on protease inhibitor therapy

Objective. The purpose of this study was to investigate the effect of HIV-1 protease inhibitors on the frequency of oropharyngeal candidiasis in HIV-infected patients. Study design. A clinical and analytic follow-up was carried out to determine the number of episodes of oropharyngeal candidiasis during HIV-1 protease inhibitor therapy and the relation of this incidence to the CD4 lymphocyte count and circulating neutrophils level. Seventy-five HlV-positive patients were selected, and HIV-1 protease inhibitor therapy was administered to each patient over a minimum of 6 months. These patients did not receive long-term preventive antifungal therapy for oral candidiasis, even as secondary prophylaxis against cryptococcosis. Results were compared with those obtained during the previous 6 months, during which patients had been treated only with reverse transcriptase inhibitors. Results. At least one episode of oropharyngeal candidiasis was seen in 56% (42/75) of patients during reverse transcriptase inhibitor therapy and in only 9.3% (7/75) of patients after the initiation of protease inhibitor therapy. The number of relapses decreased significantly when the 2 follow-up periods were compared ( P < .0001). The CD4 and CD8 lymphocyte counts increased significantly with protease inhibitor therapy ( P < .001 and P < .05, respectively). During reverse transcriptase inhibitor treatment, the probability of the presentation of oropharyngeal candidiasis correlated with falling CD4 counts ( P < .0001). The HIV-1 protease inhibitor therapy was associated with a significant increase in the neutrophil count ( P < .01). The probability of the occurrence of some episode of candidiasis correlated inversely with the circulating neutrophil level ( P < .05). Conclusions. Protease inhibitor therapy decreases the frequency of HIV-related oropharyngeal candidiasis. The mechanism involved is unknown, but it can be speculated that a reduction of the viral load increases the number of intact T helper cells, which in turn enhances the number of circulating polymorphonuclear neutrophils and regulates their function by means of colony-stimulating factors. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:437-41)

In Vivo Expression and Localization of Candida albicans Secreted Aspartyl Proteinases during Oral Candidiasis in HIV-Infected Patients

Isoforms of aspartyl proteinase (Sap), which are encoded by at least nine related SAP genes, have been implicated to be a major virulence factor of the opportunistic yeast Candida albicans in experimental infections. Although it is generally assumed that proteinases are important for infections, detailed information on the pathogenetic role of Saps is still lacking. The same applies to the question whether the genes and corresponding isoforms of the enzyme are expressed during oral infection. For in vivo investigations, parts of the lesional oral epithelium were collected from three HIV-infected patients with oropharyngeal candidiasis. Immunoelectron microscopy was performed (pre- and post-embedding gold labeling with silver enhancement) using an anti-Sap murine monoclonal antibody directed against the gene products Sap1-3. It was possible to demonstrate expression of Sap antigens in each of the three samples of human oral candidiasis. This suggests that at least one of the genes SAP1-3 was expressed at the time of sample collection. Furthermore, a possible role of the enzymes during the interaction of yeast cells and mucosal cells is suggested: the majority of Sap antigens is secreted by those C. albicans cells that adhere directly to the epithelial surface. Sap immunoreactivity can be detected in particular at the site of close contact between C. albicans and epithelial cells, suggesting a pathogenetic role of the Saps in host-fungal interaction. Thus, inhibition of the enzyme might prove to be an important alternative in the prevention and treatment of candidiasis.

Triazole therapy for mucocutaneous candidiasis in HIV-infected patients

Mucocutaneous candidiasis, such as oropharyngeal candidiasis, esophageal candidiasis, and vulvovaginal candidiasis, are common problems in patients with HIV infection. These conditions adversely affect patient quality of life and morbidity status. New oral triazole agents provide improved treatment options for patients with these and other opportunistic fungal infections; however, the development of resistance in some Candida species poses new challenges. This article provides an overview of the diagnosis of mucocutaneous candidiasis, current treatment modalities, concomitant drug interactions, common adverse drug reactions, and the emergence of fungal resistance, and it suggests nursing interventions to maximize patient benefits from antifungal therapy.

The treatment of oropharyngeal candidiasis in HIV-infected patients with oral amphotericin B suspension.

Oropharyngeal candidiasis (OPC) is the most frequent opportunistic infection associated with HIV infection. Therapies such as topical clotrimazole and nystatin, as well as oral azoles, which had previously been effective prior to the advent of HIV, are increasingly only partially effective in OPC in HIV infection. The effectiveness of oral amphotericin B suspension for OPC is described in 17 HIV-infected patients whose response to other therapies had been unsatisfactory. Three patients yielded isolates of Candida albicans with a minimum inhibitory concentration (MIC) to fluconazole of >/=16 microg/mL. Eleven patients received amphotericin B suspension monotherapy. Of the 17 patients, the symptoms of six resolved entirely, seven patients partially responded, and four failed therapy. These data suggest that amphotericin B suspension may be a useful additional therapy for OPC in HIV-infected patients.

A randomized trial of continuous or intermittent therapy with fluconazole for oropharyngeal candidiasis in HIV-infected patients: clinical outcomes and development of fluconazole resistance

Purpose: The effects of continuous or intermittent therapy with fluconazole on the recurrence of and the development of fluconazole resistance are not known. Patients and Methods: We studied human immunodeficiency virus (HIV)-positive patients with CD 4 cell count <350 × 10 6/L and oropharyngeal candidiasis in a prospective, randomized study. After initial treatment, 20 patients (16 of whom completed 3 months of follow-up) received continuous fluconazole at 200 mg/day, and 48 patients (28 of whom completed follow-up) received intermittent therapy at the time of symptomatic relapses. Oral samples were obtained weekly during episodes of infection and quarterly as surveillance cultures. Development of resistance was defined as a fourfold rise in minimum inhibitory concentration (MIC) to at least 16 μg/mL from the initial culture in the same species, the emergence of new, resistant (MIC ≥16 μg/mL) species, or a significant increase in the proportion of resistant isolates. Results: During a mean follow-up of 11 months, median annual relapse rates were lower in patients on continuous therapy (0 episodes/year) than in patients on intermittent therapy (4.1 episodes/year; P <0.001). Sterile cultures were seen in 6 of 16 (38%) patients on continuous therapy compared with 3 of 28 (11%) on intermittent therapy ( P = 0.04). Microbiological resistance developed in 9 of 16 (56%) patients on continuous treatment, compared with 13 of 28 (46%) on intermittent treatment ( P = 0.75). However, despite isolates with increased MICs, 42 of 44 patients responded to fluconazole in doses up to 800 mg/day. Conclusions: In patients with frequent recurrences, continuous suppressive therapy significantly reduced relapses and colonization. Resistance occurred with both continuous and intermittent therapy; however, therapeutic responses were excellent.

Preventing and treating azole-resistant oropharyngeal candidiasis in HIV-infected patients.

Preventing and treating azole-resistant oropharyngeal candidiasis in HIV-infected patients.

New evidence thatCandida albicanspossesses additional ATP-binding cassette MDR-like genes: implications for antifungal azole resistance

Emergence of resistance of Candida albicans to antifungal triazoles is increasingly recognized as an important cause of refractory mucosal candidiasis in HIV-infected patients. Recently, CDR1, which is thought to be analogous to the human MDR-1 P-glycoprotein, has been cloned in C. albicans. It has been proposed that its expression is partially responsible for fluconazole resistance in C. albicans. This gene is characterized by the presence of an ATP binding cassette (ABC) region and is distinct from the BENr gene which does not encode such a functional domain. As the molecular basis for fluconazole resistance appears to be multifactorial, we considered that there may be other ATP binding cassette-containing MDR genes that may potentially contribute to antifungal azole resistance in C. albicans. We therefore sought to identify potential target sequences that may be derived from candidate genes that share homology with the ATP binding cassette region of the human MDR-1 P-glycoprotein. Degenerate oligonucleotide primers based on the known sequence from the ATP binding cassette region of the human MDR-1 P-glycoprotein were used to amplify PCR products within the range of 100 bp in length from C. albicans isolates (3 fluconazole-susceptible and 3 fluconazole-resistant). Sequence analysis of individually subcloned PCR products, derived from the six isolates revealed 34 sequences in total. The results of our study identified 14 clones (with at least one per isolate) with a high degree of homology to the ATP binding cassette of the human MDR-1 P-glycoprotein. The BLAST search did not disclose homology of these new sequences to the C. albicans CDR1 gene, suggesting that C. albicans may possess more than one MDR-like gene. We conclude that C. albicans may possess one or more additional genes encoding ATP binding cassette MDR-like proteins that are distinct from CDR 1 and which could participate in the development of fluconazole resistance.

Correlation between in vitro resistance to fluconazole and clinical outcome of oropharyngeal candidiasis in HIV-infected patients.

Fifty episodes of oropharyngeal candidiasis in HIV-infected patients were analyzed prospectively in order to evaluate the clinical response to fluconazole. The minimum inhibitory concentrations (MICs) of fluconazole for the Candida strains isolated from the pharynx were correlated with the clinical response. Treatment with fluconazole (100 mg/day) was successful in 86% of the cases. A good clinical outcome followed in 97% of the cases when a strain sensitive to fluconazole was isolated. This figure fell to 22% when the strain was resistant to fluconazole (p < 0.001). The rate of post-treatment colonization was high (87%), and selection of non-albicans Candida species occurred in 23% of the cases. In conclusion, fluconazole treatment for oropharyngeal candidiasis of HIV-infected patients was useful in most cases, but less sensitive non-albicans species can be selected. Most treatment failures were associated with increased MICs of fluconazole for the strains isolated before treatment; therefore, susceptibility testing is recommended as an aid in clinical decision-making for the use of the azole group of drugs.

Epidemiology of oral candidiasis in HIV-infected patients: Colonization, infection, treatment, and emergence of fluconazole resistance

purpose: To study the epidemiology of oral candidiasis and the effect of treatment of thrush in human immunodeficiency virus (HIV)-infected patients. patients and methods: We conducted a prospective observational study of 92 patients over 1 year, including a nonblinded, randomized treatment trial of thrush with clotrimazole troches or oral fluconazole. Oral sites were cultured monthly and when thrush occurred. Candida albicans strains were typed by contour-clamped homogeneous electric field (CHEF) electrophoresis. Changes in strains were evaluated over time and in regard to their associations with particular sites, episodes of thrush, relapse after treatment, and colonization of sexual partners. Susceptibility to fluconazole was tested and CHEF analysis was done on these strains to determine the epidemiology of fluconazole resistance. results: Yeasts colonized 84% of patients. C albicans accounted for 81% of all isolates and was separated into 34 distinct strains. Most patients had persistent carriage of 1 or 2 dominant strains of C albicans. Three couples shared strains. Nineteen different C albicans strains caused 82 episodes of thrush in 45 patients. CD4 <200/μL was associated with development of thrush. Clinical cure rates were similar with fluconazole (96%) and clotrimazole (91%), but mycologic cure was better with fluconazole (49%) than clotrimazole (27%). Following mycologic cure, colonization recurred with the same strain 74% of the time. Colonization with Torulopsis glabrata and Saccharomyces cerevisiae increased after treatment with either drug, but these organisms were never a sole cause of thrush. In a subset of 35 patients followed for over 3 months in whom fluconazole susceptiblities were performed, minimum inhibitory concentrations (MICs) to fluconazole increased only in those on fluconazole prophylaxis. Clinical failure of fluconazole was associated with an MIC ≥ 64 μg/mL in 3 patients, and with an MIC of 8 μg/mL in 1 patient. In 2 of these 4 patients, the prior colonizing strain developed fluconazole resistance. In the other 2, new resistant strains were acquired. conclusions: Many different strains of C albicans colonize and cause thrush in patients infected with HIV. Patients are usually persistently colonized with a single strain, and recurrences following treatment are usually due to the same strain. Transmission of strains may occur between couples. Fluconazole and clotrimazole are equally effective in treating thrush, but mycologic cure occurs more often with fluconazole. Fluconazole resistance in C albicans occurs most often in patients who have low CD4 counts and are taking fluconazole prophylactically for recurrent thrush. Fluconazole resistance may occur through acquisition of a new resistant strain or by development of resistance in a previously susceptible strain.

HIV infection of monocyte-derived macrophages in vitro reduces phagocytosis of Candida albicans.

HIV-1 infection of peripheral blood monocyte-derived macrophages (MDMs) is unrelated to the level of CD4 expression on the surface of the cell, is associated with considerable donor variability, causes minimal cytopathology, and results in peak viral antigen production after 2 weeks of infection. Phagocytosis of opsonized Candida albicans by MDMs infected in vitro with several strains of HIV was compared with that of uninfected cells from the same donors; the proportion of MDMs containing the fluorescein isothiocyanate-labeled yeast was determined by flow cytometry and phase contrast microscopy. The intracellular localization of C. albicans was confirmed by confocal microscopy. Using paired MDMs from nine donors, 81% of uninfected and 53% of HIV-infected MDMs phagocytosed C. albicans. In addition, the number of yeast per cell was significantly higher in uninfected MDMs than in HIV-infected cells (mean 6.1 versus 2.5). These findings may partially explain the high incidence of mucocutaneous candidiasis in HIV-infected patients with advanced disease.

Correlation between in vitro susceptibility of Candida albicans and fluconazole-resistant oropharyngeal candidiasis in HIV-infected patients.

Twenty-five patients seen consecutively at an HIV outpatient clinic who had clinical evidence of oropharyngeal candidiasis and two or more oral swabs positive for yeasts on culture were studied retrospectively. For each of the 65 isolates susceptibility to fluconazole was evaluated by the disk diffusion test and determination of the minimal inhibitory concentration (MIC). A correlation was sought between clinical resistance and in vitro susceptibility data. Seven patients were non-responders and 19 were responders (one patient figuring in both groups). Significant differences were observed between the two groups with respect to the median interval after the diagnosis of AIDS (27 months in non-responders and 2 months in responders; p = 0.001), the median CD4+ cell count (6 and 21 cells/mm3 respectively; p = 0.005) and the median number of previous episodes of oropharyngeal candidiasis treated with fluconazole (13 and 2 episodes respectively; p = 0.001). Candida albicans was identified in 64 of 65 cultures. The correlation between MIC values and diameters of inhibition was good (r = 0.85; p < 0.001). The degree of in vitro susceptibility of the isolates to fluconazole showed a significant difference between non-responders and responders (mean inhibition diameters 13 and 36 mm respectively; p < 0.001) with a tentative cut-off value of 25 mm. An advanced stage of HIV infection and previous exposure to fluconazole could be risk factors for the development of fluconazole-resistant oropharyngeal candidiasis. Candida albicans strains with decreased in vitro susceptibility to fluconazole were responsible for the clinical resistance which could be predicted by a simple disk diffusion test.

Maintenance therapy of oropheryngeal candidiasis in HIV-infected patients with fluconazole

Maintenance therapy of oropheryngeal candidiasis in HIV-infected patients with fluconazole