VITEK2 Compact全自动微生物分析系统对牛乳中葡萄球菌的鉴定效果评价

Assessment of VITEK2 Compact automatic microbial analysis system for Staphylococcus in raw milk

【目的】评价VITEK2 Compact全自动微生物分析系统对牛乳中葡萄球菌属细菌鉴定效果。【方法】对从西宁、白银、西安三地乳样中分离的52株葡萄球菌通过VITEK2 Compact全自动微生物分析系统进行鉴定,并与革兰氏染色、触酶试验、血浆凝固酶试验以及16S r RNA基因序列分析结果进行比对;通过对凝固酶阴性葡萄球菌和凝固酶阳性葡萄球菌在不同麦氏浓度的鉴定,评价该系统的稳定性。【结果】VITEK2 Compact全自动微生物分析系统对葡萄球菌在"属"水平的鉴定结果符合率达96.15%,与血浆凝固酶结果对比,凝固酶阴性葡萄球菌属细菌鉴定结果符合率为92.86%,对凝固酶阳性葡萄球菌属细菌鉴定结果符合率为50%,但对具体种鉴定时,结果符合率仅为44.23%。在稳定性检测的试验中,鉴定符合率为100%,鉴定结果可靠性不随菌液浓度变化而变化。【结论】该系统可用于牛乳中葡萄球菌在"属"水平的鉴定。

[Objective] In order to evaluate the VITEK2 Compact automatic microbial analysis system in identifying Staphylococcus in raw milk. [Methods] We isolated 52 strains of Staphylococcus from milk samples from Xining, Baiyin and Xi＇an, and these strains were identified by VITEK2 Compact. Then, we compared the results obtained from VITEK2 Compact to the results from Gram＇s staining, catalase test, plasma coagulase test and 16 S r RNA gene sequence analysis. Furthermore, the stability of this system was tested by identifying the coagulase negative and positive Staphylococcus at different concentrations. [Results] With 16 S r RNA gene sequence analysis as the reference standard, the coincidence rate of this system reached 96.15% for Staphylococcus at ＂Genus＂ level. With plasma coagulase test as the reference standard, the coincidence rate of this system was 92.86% for the coagulase negative Staphylococcus while 50% for the coagulase positive Staphylococcus. When it came to ＂Species＂ level, the coincidence rate of this system was only 44.23%. In stability test, coincidence rate was 100% and the reliability of appraisal result did not change by bacteria liquid concentration. [Conclusion] In conclusion, VITEK2 Compact automatic microbial analysis system could be used to identify Staphylococcus in milk at ＂Genus＂ level.