Claxton P M, Masterton R G
Central Microbiological Laboratories, Western General Hospital, Edinburgh.
J Clin Pathol. 1994 Sep;47(9):796-8. doi: 10.1136/jcp.47.9.796.
To evaluate rapid organism identification on positive blood culture Bactec NR media (phial types 26, 27, 42 and 17), and to assess the usefulness of these procedures in a diagnostic microbiology laboratory.
Two hundred and sixty, first positive, blood culture bottles from individual patients were tested by rapid identification methods selected on the basis of Gram film organism morphology. Tube coagulase and latex agglutination were applied to presumptive staphylococci; latex agglutination antigen detection methods to suspected pneumococci, Neisseria and Haemophilus sp; and latex agglutination grouping tests for cultures thought to be non-pneumococcal streptococci.
Media type did not influence test performance (p > 0.05 for all comparisons). Misapplication of methods occurred on eight occasions and there were 14 false positive results, nine involving the latex reagents for group C streptococci and pneumococci. The positive predictive values for tube coagulase tests and latex reactions for H influenzae type b, and N meningitidis groups B and C were 100%. The pneumococcal and staphylococcal latex tests gave positive predictive values of 94.1% and 62.5%, respectively, and the corresponding figure for streptococcal grouping reactions was 75.9%. With the exception of staphylococcal latex testing (80%) all investigation negative predictive values were > 90%.
The performance of the staphylococcal latex agglutination method was unsatisfactory and it is not appropriate for use with the media studied. In view of the cross-reactions observed with the tests used to identify group C streptococci and pneumococci, positive findings must be interpreted with caution. In all other regards the protocol evaluated produced rapid, reliable, clinically useful information and, subject to local experience, is recommended to users of Bactec NR media.
评估使用Bactec NR血培养瓶（瓶型26、27、42和17）进行快速微生物鉴定，并评估这些方法在诊断微生物实验室中的实用性。
从个体患者采集的260份首次阳性血培养瓶，根据革兰氏染色涂片上微生物形态选择快速鉴定方法进行检测。对疑似葡萄球菌应用试管凝固酶试验和乳胶凝集试验；对疑似肺炎球菌、奈瑟菌和嗜血杆菌属应用乳胶凝集抗原检测方法；对认为是非肺炎链球菌的培养物应用乳胶凝集分组试验。
培养瓶类型不影响检测性能（所有比较p>0.05）。方法误用发生8次，有14例假阳性结果，9例涉及C组链球菌和肺炎球菌的乳胶试剂。b型流感嗜血杆菌、B群和C群脑膜炎奈瑟菌的试管凝固酶试验和乳胶反应的阳性预测值为100%。肺炎球菌和葡萄球菌乳胶试验的阳性预测值分别为94.1%和62.5%，链球菌分组反应的相应数值为75.9%。除葡萄球菌乳胶检测（80%）外，所有检测的阴性预测值均>90%。
葡萄球菌乳胶凝集法的性能不令人满意，不适用于所研究的培养瓶。鉴于在鉴定C组链球菌和肺炎球菌的试验中观察到交叉反应，阳性结果必须谨慎解释。在其他所有方面，所评估的方案产生了快速、可靠、对临床有用的信息，根据当地经验，推荐给使用Bactec NR培养瓶的用户。
