ObjectiveTo evaluate the accuracy and practicability of matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) in clinical isolates of mycobacteria.MethodsWe collected all tested strains, which were positive for Mycobacterium tuberculosis culture and positive for acid-fast staining, from West China Hospital of Sichuan University from 2014 to 2017, eliminating duplicate strains sent by the same patient at the same time. The traditional method was used with the P-nitrobenzoic acid (PNB)/ 2-Thiophenecarboxylic acid hydrazide (TCH) indicator to initially identify acid-resistant positive strains. Mycobacteria was identified by MALDI-TOF MS; the specificity and sensitivity of the MALDI-TOF MS was analyzed by duplex primer-polymerase chain reaction (Duplex-PCR) method and DNA sequencing method as the "gold standard" for the identification.ResultsA total of 237 anti-acid positive strains were collected; Mycobacterium tuberculosis complex (MTC) and non-tuberculous mycobacteria (NTM) were identified by mycobacterium double primer PCR, and NTM was identified by 16S rRNA gene sequencing. There were 218 cases of MTC and 19 cases of NTM. The results of preliminary identification using the traditional identification method of PNB/TCH indicator showed that there were 209 cases of MTC (with the sensitivity of 95.9%, specificity of 100.0%, positive predictive value of 100.0%, and negative predictive value of 67.9%) and 28 cases of NTM (with the sensitivity of 100.0%, specificity of 95.9%, positive predictive value of 67.9%, and negative predictive value of 100.0%). The results of MALDI-TOF MS method indicated that there were 199 cases of MTC (with the sensitivity of 91.3%, specificity of 100.0%, positive predictive value of 100.0%, and negative predictive value of 50.0%), 32 cases of NTM (with the sensitivity of 68.4%. specificity of 94.0%, positive predictive value of 40.6%, and negative predictive value of 97.1%), and 6 cases of others. There were 168 strains (84.4%) with the identification score>1.9 obtained by MALDI-TOF MS method.ConclusionsMALDI-TOF MS is a better method for identifying mycobacteria, which has the same identification results as the traditional methods, and has low cost and is suitable for routine use in clinical microbiology laboratories.
Objective To summarize the online practice teaching experience in laboratory medicine during the coronavirus disease 2019 (COVID-19) epidemic, and explore a new practice teaching mode of laboratory medicine which can provide a reference for improving the efficiency and quality of laboratory medicine education. Methods From June 8th, 2020 to June 30th, 2020, an online questionnaire survey was conducted in teachers and students who participated in online internship teaching and learning during the COVID-19 epidemic to evaluate the effect of online internship teaching and compare the advantages and disadvantages of online and offline internships. ResultsA total of 65 valid questionnaires were collected from 35 students and 30 teachers. There was no statistically significant difference in the satisfaction scores of intern students between online and offline internships [median (minimum, maximum): 100 (80, 100) vs. 100 (80, 100), P>0.05]. Among the teachers surveyed, 90.0% thought that the pre-teaching preparation for online internship teaching was more complicated and time-consuming, 60.0% thought that the online teaching was more difficult, and 63.3% thought that online internship could not achieve the expected results. Both the teachers and students believed that online and offline internships had their own advantages and disadvantages, and they could learn from each other. Conclusions The present online practice model cannot replace the traditional offline practice. A diversified practice model combining online and offline can help further develop and improve medical laboratory practice teaching.