Synergic effects of tactolimus and azole antifungal agents against azole-resistant Candida albican strains. (1/466)

We investigated the effects of combining tacrolimus and azole antifungal agents in azole-resistant strains of Candida albicans by comparing the accumulation of [3H]itraconazole. The CDR1-expressing resistant strain C26 accumulated less itraconazole than the CaMDR-expressing resistant strain C40 or the azole-sensitive strain B2630. A CDR1-expressing Saccharomyces cerevisiae mutant, DSY415, showed a marked reduction in the accumulation of both fluconazole and itraconazole. A CaMDR-expressing S. cerevisiae mutant, DSY416, also showed lower accumulation of fluconazole, but not of itraconazole. The addition of sodium azide, an electron-transport chain inhibitor, increased the intracellular accumulation of itraconazole only in the C26 strain, and not in the C40 or B2630 strains. Addition of tacrolimus, an inhibitor of multidrug resistance proteins, resulted in the highest increase in itraconazole accumulation in the C26 strain. The combination of itraconazole and tacrolimus was synergic in azole-resistant C. albicans strains. In the C26 strain, the MIC of itraconazole decreased from >8 to 0.5 mg/L when combined with tacrolimus. Our results showed that two multidrug resistance phenotypes (encoded by the CDR1 and CaMDR genes) in C. albicans have different substrate specificity for azole antifungal agents and that a combination of tacrolimus and azole antifungal agents is effective against azole-resistant strains of C. albicans.  (+info)

Adhesive and mammalian transglutaminase substrate properties of Candida albicans Hwp1. (2/466)

The pathogenesis of candidiasis involves invasion of host tissues by filamentous forms of the opportunistic yeast Candida albicans. Morphology-specific gene products may confer proinvasive properties. A hypha-specific surface protein, Hwp1, with similarities to mammalian small proline-rich proteins was shown to serve as a substrate for mammalian transglutaminases. Candida albicans strains lacking Hwp1 were unable to form stable attachments to human buccal epithelial cells and had a reduced capacity to cause systemic candidiasis in mice. This represents a paradigm for microbial adhesion that implicates essential host enzymes.  (+info)

In vivo expression and localization of Candida albicans secreted aspartyl proteinases during oral candidiasis in HIV-infected patients. (3/466)

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.  (+info)

Immunocytochemical detection of Candida albicans in formalin fixed, paraffin embedded material. (4/466)

AIM: To assess the ability of the commercially available monoclonal antibody 1B12 (BioGenex, San Ramon, USA) to identify C albicans in formalin fixed, paraffin wax embedded material (FFPE). METHODS: Broth cultures of 20 strains of seven Candida species were resuspended in 4% agarose blocks, fixed in formalin for 24 hours, and embedded in paraffin wax. In addition, 16 blocks of FFPE tissue known to contain periodic acid-Schiff positive fungal hyphae were examined. Antigen retrieval involved microwave treatment of specimens in citrate buffer (0.01 M; pH 6.5) before addition of 1B12 antibody for 24 hours. Bound antibody was subsequently detected using a biotinylated link antibody and a peroxidase conjugated streptavidin. RESULTS: Only C albicans strains were 1B12 positive in the agarose blocks. All FFPE tissue blocks were found to contain 1B12 positive hyphal structures, indicating the presence of C albicans. CONCLUSIONS: The ability to identify candida organisms penetrating the lesional tissue in cases of chronic hyperplastic candidosis will help to clarify the role of individual Candida spp in this important form of oral candidosis.  (+info)

Assessment of therapeutic response of oropharyngeal and esophageal candidiasis in AIDS with use of a new clinical scoring system: studies with D0870. (5/466)

We developed and compared five scoring systems designed to quantitate therapeutic response in cases of oropharyngeal candidiasis. We utilized prospectively collected data on 114 patients treated with several doses of the azole D0870. Patients were infected with fluconazole-susceptible (n = 49) or -resistant organisms (MIC, > or = 16 mg/mL; n = 61). Patients with fluconazole resistance had lower CD4+ cell counts at baseline; more symptoms (P = .0006); a higher frequency of dysgeusia (P = .004), dysphagia (P = .006), and throat pain (P = .0034); and greater oral coverage by plaques of Candida. There was no difference between the two groups in terms of colony-forming units, and any change did not correlate with response to therapy. Resolution of dysphagia (P < .01) and oral pain (P < .01) correlated well with response to therapy, unlike retrosternal pain and throat pain, which were also less frequent. Xerostomia, a "furry" taste, and dysgeusia were frequent nonspecific symptoms. Scoring system C, weighting resolution of a symptom higher than absence of a symptom at baseline, yielded the best correlation with global outcome (r = 0.86) and allows the quantitation of incomplete but clinically beneficial responses to therapy.  (+info)

Evaluating diagnosis and treatment of oral and esophageal candidiasis in Ugandan AIDS patients. (6/466)

A randomized cross-over clinical and endoscopic evaluation of 85 Ugandan patients showed that esophageal candidiasis in AIDS patients with oral candidiasis could be managed without endoscopy and biopsies. Oral lesions, especially when accompanied by esophageal symptoms, were sufficient for diagnosis. Miconazole was more effective than nystatin in treating esophageal candidiasis and could be a valid alternative to more expensive azolic drugs in developing countries.  (+info)

Non-albicans oral candidosis in HIV-positive patients. (7/466)

Specimens from HIV-positive patients with oral candidosis were taken for culture, species identification and azole susceptibility testing, which was correlated with treatment outcome. Of 921 specimens, 95 yielded non-albicans species, mainly from patients with low CD4 lymphocyte counts and extensive previous azole exposure. Most non-albicans isolates were from specimens co-infected with Candida albicans, complicating the interpretation of in-vitro susceptibility results, which accurately predicted antifungal failure when the non-albicans species was isolated alone. Eighty-five non-albicans isolates were resistant to fluconazole in vitro. Of 149 courses of azole therapy prescribed, 115 failed to clear non-albicans candidosis clinically. Culture media that discoloured in the presence of non-albicans colonies might, therefore, guide therapy.  (+info)

In vivo analysis of secreted aspartyl proteinase expression in human oral candidiasis. (8/466)

Secreted aspartyl proteinases are putative virulence factors in Candida infections. Candida albicans possesses at least nine members of a SAP gene family, all of which have been sequenced. Although the expression of the SAP genes has been extensively characterized under laboratory growth conditions, no studies have analyzed in detail the in vivo expression of these proteinases in human oral colonization and infection. We have developed a reliable and sensitive procedure to detect C. albicans mRNA from whole saliva of patients with oral C. albicans infection and those with asymptomatic Candida carriage. The reverse transcription-PCR protocol was used to determine which of the SAP1 to SAP7 genes are expressed by C. albicans during colonization and infection of the oral cavity. SAP2 and the SAP4 to SAP6 subfamily were the predominant proteinase genes expressed in the oral cavities of both Candida carriers and patients with oral candidiasis; SAP4, SAP5, or SAP6 mRNA was detected in all subjects. SAP1 and SAP3 transcripts were observed only in patients with oral candidiasis. SAP7 mRNA expression, which has never been demonstrated under laboratory conditions, was detected in several of the patient samples. All seven SAP genes were simultaneously expressed in some patients with oral candidiasis. This is the first detailed study showing that the SAP gene family is expressed by C. albicans during colonization and infection in humans and that C. albicans infection is associated with the differential expression of individual SAP genes which may be involved in the pathogenesis of oral candidiasis.  (+info)

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