Study of susceptibility of candida species in patients with malignant tumors

Abstract

Objective To evaluate the clinical application of disk diffusion method(ROSCO company of Denmark) for testing the susceptibility of candida species isolated from patients with cancer with the using broth microdilution method ((NCCLS) M27-A of America Committee for clinical laboratory standards) as the gold standard in order to find the better method for clinical laboratory.Methods Antifungal susceptibility (5-flucytosine,amphotericin B,fluconazole and itraconazole) of 78 strains of Candida species were tested both by ROSCO disk diffusion method and ATB FUNGUR2 broth microdilution method.The microdilution method NCCLS as the gold standard.The sensitivity,specificity,positive and negative predictive values of two methods was calculated.Results The Kappa value was reached to 0.89 in term of disk diffusion method for detecting susceptibility of candida to 5-flucytosine,amphotericin B,fluconazole and itraconazole,suggesting that no serious errors was seen in terms of sensitive and resistant another method.Of 78 strains of candida,they had the high susceptibility to 5-flucytosine,amphotericin B,which were 88.20％ and 89.17 ％.The lower susceptibility of 78 strains of candida was fluconazole and itraconazole (56.34％ and 52.12％).Candida glabrata and candida krusei were proved to suspect to four kinds of antifungal agents(90.95％,85.71％).And the lowest positivity was 67.50％ and 41.67％ regarding of candida glabrata and candida krusei.Conclusion The higher consistency was seen in terms of detecting candida susceptibility to antibiotics by disk diffusion method and microdilution method,suggesting disk diffusion method can replace microdilution method.In bur hospital,candida species are susceptibility to amphotericin B at the highest sensitivity and courtyard albicans at lower sensitivity.Antifungal agents works to candida albicans and lower inhibition rate to candida kruse. Key words: Malignant tumor; Candida infection; Disk diffusion method