| Objective:1.Analyze the clinical characteristics of patients with Candida tropicalis infection,identify the relevant risk factors of patients infected with this bacteria,and provide effective measures and suggestions for the prevention of Candida tropicalis infection.2.To understand the current status and characteristics of Candida tropical’s resistance to various antibacterial drugs,and provide a theoretical basis for the rational use of antibacterial drugs in clinical practice.3.The biofilm formation capacity of Candida tropicalis was clarified,and its effect on drug resistance was analyzed.4.To analyze the expression of genes related to the formation of Candida tropicalis biofilm.Methods:1.From September 2020 to September 2022,clinical isolates of deep body fluid infection of Candida tropicalis from the First Affiliated Hospital of Nanchang University were collected.All strains were identified by the VITEK-II Compact automated microbial analyzer.2.The clinical data of patients with Candida tropicalis infection were collected,the clinical features of patients with Candida tropicalis infection were retrospectively analyzed,and univariate analysis and multivariate conditional logistic regression analysis were used to analyze the clinical features and infection-related risk factors of patients.3.In vitro drug sensitivity test was carried out on 8 antifungal drugs,namely anifengin,micafungin,caspofungin,flucytosine,voriconazole,itraconazole,fluconazole and amphotericin B.4.The biofilm formation of Candida trophida was quantitatively analyzed by crystal violet staining,and the expression of biofilm formation related genes in different states was detected by RT-q PCR.Results:1.The average age of the 51 patients with Candida tropicalis infection was55.49±15.17 years;58.82%(30/51)and 41.18%(21/51)female;Department distribution: mainly from general surgery,accounting for 21.57%;The types of infection of patients were mainly bloodstream infections,accounting for 54.90%.Mechanical ventilation > 7 days,indwelling gastric tube > 7 days,and jejunal nutrition tube are independent risk factors for Candida tropicalis infection.2.Among the 51 strains of Candida tropics,the positive detection rate of biofilm was 98.04%,and only 1 strain(1.96%)did not form biofilm.Among them,biofilms were strongly positive(+++),moderately positive(++),weakly positive(+)and negative(-)accounted for 25.49%,47.06%,25.49% and 1.96%,respectively.3.The overall drug resistance of 51 strains of Candida tropicalis was mainly fluconazole resistance rate of 39.22%,voriconazole resistance rate of 33.33%,itraconazole resistance rate of 21.57%,and amphotericin B resistance rate of 5.88%.There was a statistically significant correlation between the resistance rate of voriconazole and fluconazole and the biofilm formation capacity of the strains(P<0.05).4.The results of gene detection related to biofilm formation showed that the average expression levels of ALS1,ALS2,BCR1,EFG1 and WOR1 genes in Candida trophida in the biofilm state were higher than those in the planktonic state,and the difference was statistically significant(P<0.05).Conclusion:1.Studies have found that 7 days of mechanical >ventilation,7 days of indwelling gastric tube > and jejunal feeding tube are independent risk factors for Candida tropicalis infection,so patients who use mechanical ventilation and indwelling gastric tube and indwelling jejunal nutrition tube should be regarded as the key prevention and control targets of Candida tropicalis infection.2.The 51 strains of Candida tropicalis had varying degrees of resistance to antifungal drugs,mainly to triazole antifungals.3.The biofilm formation ability of 51 strains of Candida tropicalis was strong,and there was a correlation between biofilm formation ability and drug resistance.4.Five genes,ALS1,ALS2,BCR1,EFG1 and WOR1,participated in the biofilm formation process of Candida tropicalis. |
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