Clinical evaluation of chromogenic medium of Candida
[Abstract] Objective: To evaluate the application value of Chromium Candida chromogenic medium in the identification of clinical Candida. METHODS: Seventy-five strains of Candida were identified by Candida chromophore chromogenic medium and API 20C AUX, and the results of the two methods were statistically compared. RESULTS: There were no significant differences in the four clinically common Candida strains, Candida albicans, Candida tropicalis, Candida glabrata, and Candida krusei, which were identified by the two methods. The χ2 test was used, P>0.05. Among them, 5 strains of Candida chromogenic medium were identified as other Candida (the colonies on the medium were only white), and 4 strains of API 20C AUC were identified as other Candida species. The coincidence rate of Chromium Candida chromogenic medium and API 20C AUX identification was 98.5%. Conclusion: The chromogenic medium of Candida can be rapidly isolated and cultured to identify common Candida species. The identification results are accurate and reliable.
[Key words] Candida cerevisiae; chromogenic medium; identification system; clinical application
In recent years, with the use of broad-spectrum antibiotics, adrenocortical hormones, immunosuppressive agents, organ transplantation, malignant tumor radiotherapy and chemotherapy, various invasive procedures, diabetic patients, hematological patients, and low immunity to HIV infection, clinically The infection of Candida has increased year by year. Komajia chromogenic medium is a rapid isolation and culture of Candida albicans on the medium to identify clinical common Candida albicans, Candida tropicalis, Candida glabrata, Candida krusei, timely Clinically provide diagnostic treatment. The clinical application analysis of the chromogenic medium of Candida in the paper is as follows:
1 Materials and methods
1.1 Specimen Sources From January 2009 to May 2010, 142 specimens of suspected fungal infections, such as cervical (or vaginal) secretions, sputum, urine, blood, stools, etc., were collected by the hospital. Seven strains of Candida culture were isolated from the culture medium. Identification reagents: Candida chromogenic medium produced by Zhengzhou Bosai Company, French BioMérieux API 20C AUX, 30 ° C and 37 ° C constant temperature incubator.
1.2 Method 1.2.1 The specimens were inoculated with C. faecalis chromogenic medium, cultured at 37 ° C for 24 to 48 h, colony growth was positive on the medium, and Gram staining confirmed whether there were spores and hyphae. 7 d did not grow negative.
1.2.2 At the same time, the Candida isolated and cultured on the chromogenic medium was formulated into a turbidity of 2 gram units, strictly in accordance with the instructions of API 20C AUX, and incubated at 30 ° C for 48-72 h. The results were read and automatically processed by ATBCIRS software. The code gives the yeast name.
1.2.3 Emerald colonies (about 2 mm in diameter) grown on the chromogenic medium of C. albicans are Candida albicans, blue-gray colonies (about 1.5 mm in diameter) are tropical Candida, light (powder) red edges The fuzzy hairy (4~5 mm in diameter) is Candida krusei, the purple red colony (about 2 mm in diameter) is Candida glabrata, and the white is other Candida.
1.3 Statistical methods SPSS 11.5 was used for statistical analysis. The count data was expressed as the rate (%). The goodness of fit χ2 test was used, and the difference was statistically significant at P<0.05.
2 Results There were no significant differences between Candida albicans, Candida tropicalis, Candida glabrata, and Candida krusei identified by two methods, P>0.05, Candida chromogenic medium and API 20 C AUX identification The overall coincidence rate of clinical common Candida was 98.5%, and the identification results are shown in Table 1. The classification results on the chromogenic medium of Candida can be found in Table 2.
3 Discussion The four clinical common Candida strains identified by two methods—Candida albicans, Candida tropicalis, Candida glabrata, and Candida krusei—have no significant difference, P>0.05. The chromogenic medium of Candida bacterium and API 20 C AUX identified the overall compliance rate of four clinical common Candida species to 98.5%. Chromogenic medium was identified in 47 strains of Candida, 47 strains of Candida albicans (62.7%), 12 strains of Candida tropicalis (16.0%), 7 strains of Candida glabrata (9.3%), and 4 strains of Candida krusei (5.3%). 5 other strains of Candida (6.7%). Four Candida species accounted for 93.3% of the total number of identified plants, indicating that Candida catarrhalis chromogenic medium can identify more than 90% of clinically common Candida species, which can be used for routine yeast identification.
The four most common clinical Candida species accounted for 95.3% of the total number of Candida, while the proportion of Candida in deep fungal infections was as high as 87.5% to 94.5%. Among the four Candida species, Candida albicans was the main infection, Candida albicans It is still the most common pathogen for deep candida infection.
Candida chromogenic medium is a selective identification medium for rapid isolation and identification of Candida by different colors and forms of colonies. It can identify Candida albicans, Candida tropicalis, and smooth at 24 to 72 h. Candida, Candida krusei, but found in practice, for Candida albicans and Candida krusei, because of the obvious color and colony characteristics, can be quickly and accurately identified in 24 ~ 48 h, and smooth rosary The bacteria and tropical Candida require a longer period of time (48-72 h), so that the color of the colonies is fully visible and can be accurately judged. Candida can be identified by API 20C AUC for a very small number of Candida species that cannot be identified on the Cimajia chromogenic medium.
The chromogenic medium of Candida can be used to quickly and accurately identify clinically common yeasts. The specimens can be seen for 24 to 48 hours. The cost of API 20C AUX is relatively high, and the time required for identification is long. After the specimen is cultured for 24 hours, it is identified again for 48-72 hours. Software is also required. The Komajia chromogenic medium not only shortens the identification time, but also the price is cheap. It is simple and accurate, and the identification result is accurate and reliable. It can make a clear judgment for mixed Candida infection and is suitable for large, medium and small laboratories in China. It is especially suitable for use in the basic clinical microbiology laboratory, which not only meets the clinical requirements, but also compensates for the lack of experimental equipment in the microbiology laboratory of the primary hospital.
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