摘要
Objective:Identification of otomycotic fungi using matrix-assisted laser desorption ionization (MALDI) time of flight (TOF) mass spectroscopy (MS) and to quantify pervasive errors with Bayes rule;values of sensitivity and specificity of culture test and MALDI-TOF-MS method are quantified.Method:Fungi cultured ear discharge samples were identified with culture test and MALDITOF-MS system.Minimum inhibitory concentration (MIC) or MEC (minimum effective concentration) for 6 antifungals were determined by antifungal susceptibility testing in vitro.With Bayes rule,sensitivity and specificity of both MALDI-TOF MS and culture test methods were computed.Results:Cultures yielded 42 fungal isolates which were confirmed as species (specified against each species) belonging to 8 genera,A.niger 22,Candida sp.7,A.fumigatus 3,A.flavus 3,mixed Aspergillus sp.3,Mucor sp.2,Rhizopus sp.1,and Scopulariopsis sp.1;and MALDITOF-MS system also confirmed those isolates.In vitro antifungal susceptibility testing with terms of MIC 50 and MIC 90,isolates fungi were highly susceptible to 6 antifungals;and caspofungin was the most active antifungal.The high value of specificity 84.6%,suggested a limited loss of confidence on the culture test at the absence of an infection,in comparison to MALDI-TOF-MS.Sensitivity of the culture test was 87.5%;this high figure strongly approves the culture test to be the dependable method for the otomycosis diagnosis,when the infection is stable.Conclusion:Based on sensitivity and specificity together the culture test could be done in face of the gold-standardMALDI-TOF-MS system the estimating both methods.
