两种前处理方法对血培养直接药敏的影响

Effects of two pretreatment methods on direct drug sensitivity of blood culture

目的比较两种血培养直接药敏方法与常规药敏方法结果的一致性,评估两种前处理方法对血培养直接药敏的影响。方法选取上海某三级教学医院2017年9月至2018年5月共241例血培养阳性样本,用分离胶管离心后分别使用直接检测法和TSB肉汤增菌法两种前处理方法获得细菌,并配置菌悬液,选择相应药敏卡进行药敏试验,得到的药敏结果与转种后获得菌落的常规药敏结果进行比较。结果革兰阴性菌分离胶离心后直接检测法和增菌法与标准方法类别一致性分别为98.53%和98.74%(2753/2794、2759/2794),非常重大错误(VME)分别为0.21%和0.18%(6/2794、5/2794),重大错误(ME)分别为0.17%和0.21%(5/2794、6/2794),微小错误(MIE)分别为1.47%和1.25%(30/2840、24/2840)。革兰阳性球菌(除链球菌)分离胶离心后直接检测法和增菌法与标准方法类别一致性为98.46%和99.13%(2048/2080、2061/2080),VME分别为0.34%和0.10%(7/2080、2/2080),ME分别为0.14%和0.19%(3/2080、4/2080),MIE分别为1.06%和0.63%(22/2080、13/2080)。链球菌两种前处理方法与标准法类别一致性为100.00%(140/140)。经过统计学分析,两种前处理方法直接体外药敏试验结果与标准法结果差异无统计学意义(P>0.05)。结论两种前处理直接药敏结果与标准法总符合率均为>98.00%,分离胶离心直接检测法操作简单无需繁琐的增菌过程,可以作为微生物实验室血培养替代直接药敏实验传统纸片法的一种方便又可靠的前处理方法。

Objective To compare the results of two direct drug sensitivity methods in blood culture with those of conventional drug sensitivity methods,and to evaluate the effects of two pretreatment methods on direct drug sensitivity in blood culture.Methods A total of 241 blood culture positive samples from a tertiary teaching hospital in Shanghai from September 2017 to May 2018 were selected.After centrifugation with separation hose,bacteria were obtained by two pretreatment methods respectively,namely direct detection method and TSB broth enrichment.Bacteria suspension was prepared,and corresponding drug sensitivity cards were selected for drug sensitivity test.The drug sensitivity results obtained were compared with the conventional drug sensitivity results of colonies obtained after seed transfer.Results After centrifugation of Gram-negative bacteria isolation gel,categorical agreement(CA)between the direct method and the standard method was 98.53%and 98.74%(2753/2794,2759/2794),very major error(VME)was 0.21%and 0.18%(6/2794,5/2794),major error(ME)was 0.17%and 0.21%(5/2794,6/2794),minor error(MIE)was 1.47%and 1.25%(30/2840,24/2840).After centrifugation of Gram positive cocci(except Streptococcus)isolation gel,CA between the enrichment method and the standard method was 98.46%and 99.13%(2048/2080,2061/2080),VME was 0.34%and 0.10%(7/2080,2/2080),ME was 0.14%and 0.19%(3/2080,4/2080),MIE was 1.06%and 0.63%(22/2080,13/2080).The results of these two methods in Streptococcus were 100.00%(140/140)consistent with the standard method.After statistical analysis,there was no significant difference between the direct in vitro drug sensitivity test results of the two pretreatment methods and the standard method(P>0.05).Conclusion CA between these two methods and the standard method is>98.00%.The separation gel centrifugation direct detection method is simple to operate and does not need cumbersome enrichment process.It can be used as a convenient and reliable pretreatment method for microbial laboratory blood culture to replace the traditional paper method.