| The incidence of fungal infections has been increasing worldwide, especially deep fimgal infections (DFI). The AIDS epidemic and advances in therapeutic and diagnostic technology contribute to the dramatic rise of invasive fungal infections over the past decade, and their expected boost in coming years. Though great progress have been got in the research and development of new antifungal drugs, Fluconazole (FCZ) and Itraconazole (ICZ) are often used as empirical therapy to control fungal infection. These two drags have been applied to clinical use for about 20 years. There is a growing number of publications describing the shift in the infection pathogen from Candida albicans to non-albicans species and the serious resistance of Candida to these agents, which aggravating the difficulty of treatment. There is limited data in west china hospital of which owing more than 3460 beds.In order to collect the epidemiological data of deep fungal infections and find out the features of pathogenic fungus as well as investigate the susceptibility of Candida species(C.spp) to the two widely used azoles and honokiol(HNK), we conduct the project both from clinical case analysis and the vitro susceptibility of C.spp to the selective drugs to provide theoretic guidance for new antifungal drugs in the clinical practice. Part 1129 cases of deep fungal infections confirmed microbiologically or by biopsy from Sept 2005 to 2006 in the West China hospital affiliated to SiChuan University were retrospectively analyzed. We investigate the major predisposing factor, incidence and risk factors, antifungal therapy and prognosis of fungal infection. Statistics analysis was finished by SPSS 12.0 software(a=0.05, P＜0.05)as the limitation of statistical significance.Results: There was a higher occurrence rate of nosocomial fungal infection in old-aged patients, or those suffering from either malignant tumor, haematological malignancies or acute pancreatitis. The applying of broad-spectrum antibiotics, cortical hormones, immunity inhibitory agents and catherization was predisposing factors to nosocomial infection caused by fungi. Candida species was the main pathogens causing nosocomial fungal infection (90%). Among them, detective rate of Candida albicans was 22%, and other Candida spp was 70%. Cryptococcus is also the main pathogen fungi among community acquired which frequently invaded the nerve system and disseminating all over the body.Part twoSusceptibility testing was performed using microdilution method according to NCCLS-M27.. We also calculated the FICI after studying on HNK to 24 isolates and the unification with the two azoles, and then scanned the ultrastructure of ATCC64550 under transmission electron microscope (TEM).Result: Some isolates (9%) were resistant to FCZ and 15% to ICZ. Cross resistant to azoles existed among 6 isolates. C. albicans isolates were less susceptible to FCZ than other species. 50%(2/4) isolate of C. krusei was not susceptible to azoles. We investigated the clinical background of drug-resistant isolates and found no patient had used systemic antifungal. We found that doctors were lack of the knowledge of using antifungal reasonably. 24 strains of Candida spp was used to evaluate the antifungal activity of HNK according the above method. Results showed that HNK displayed lower antifungal activity with MIC 12.5～100μg/ml. It make no differences in antifungal activity among the four sorts of Candida. we studied its combination effects with FCZ and ICZ either.The assay was carried out in flat-bottomed 96-well microtiter plate with a final concentration of 0.125～64μg/ml for FCZ and 3～400μg/ml for HNK. The combination effects was evaluated by calculating the FIC index. When in combination with the two azoles no synergetic antifungal effects were observed with HNK. The effects of HNK on the ultrastructure of the resistant C. albicans cells was evaluated under TEM. One azole resistant strain with MIC 64μg/ml was used with a final working suspension density at 3×10~6 CFU/ml respectively.The ultrastructural images we got from TEM demonstrated that FCZ and HNK could damage the ultrastructure of the tested isolates. Damages were observed in the formation and integrity of cell wall and cell membrane under TEM such as the density of the cell wall became lower and a light area occurred between the wall and membrane. Also, the plasma membrane became discontinuous, the cytoplasm aggregated and leaked out in some cells. Generally, the damages were more severe compared to the negative control.Conclusions: Candida albicans were the most frequent organisms isolated in West China hospital. Clinical laboratory should identify the isolates to species and do the microbial sensitivity tests. It will be more helpful for clinicians to treat the Candida infection according the microbial sensitivity tests. |
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