Church Deirdre L, Baxter Heather, Lloyd Tracie, Larios Oscar, Gregson Daniel B
Division of Microbiology, Calgary Laboratory Services, University of Calgary, Calgary, Alberta, Canada
Departments of Pathology & Laboratory Medicine, University of Calgary, Calgary, Alberta, Canada.
J Clin Microbiol. 2017 Jul;55(7):2137-2142. doi: 10.1128/JCM.00043-17. Epub 2017 Apr 26.
Life-threatening infection in neonates due to group B (GBS) is preventable by screening of near-term pregnant women and treatment at delivery. A total of 295 vaginal-rectal swabs were collected from women attending antepartum clinics in Calgary, Alberta, Canada. GBS colonization was detected by the standard culture method (Strep B Carrot Broth subcultured to blood agar with a neomycin disk) and compared to recovery with Strep Group B Broth (Dalynn Biologicals) subcultured to StrepB chromogenic medium (CM; Bio-Rad Laboratories) and the Fast-Track Diagnostics GBS real-time PCR (quantitative PCR [qPCR]) assay (Phoenix Airmid Biomedical Corp.) performed with broth-enriched samples and the Abbott sp/rt system. A total of 62/295 (21%) women were colonized with GBS; 58 (19.7%) cases were detected by standard culture, while CM and qPCR each found 61 (20.7%) cases. The qPCR and CM were similar in performance, with sensitivities, specificities, and positive and negative predictive values of 98.4 and 98.4%, 99.6 and 99.6%, 98.4 and 98.4%, and 99.6 and 99.6%, respectively, compared to routine culture. Both qPCR and CM would allow more rapid reporting of routine GBS screening results than standard culture. Although the cost per test was similar for standard culture and CM, the routine use of qPCR would cost approximately four times as much as culture-based detection. Laboratories worldwide should consider implementing one of the newer methods for primary GBS testing, depending on the cost limitations of different health care jurisdictions.
通过对近期孕妇进行筛查并在分娩时进行治疗，可预防新生儿因B族链球菌（GBS）感染而危及生命。从加拿大艾伯塔省卡尔加里产前诊所就诊的女性中总共采集了295份阴道直肠拭子。采用标准培养方法（将B族链球菌胡萝卜肉汤接种到含新霉素纸片的血琼脂上进行传代培养）检测GBS定植情况，并与将B族链球菌肉汤（Dalynn Biologicals公司）接种到B族链球菌显色培养基（CM；伯乐公司）上进行传代培养以及对肉汤增菌样本进行快速诊断GBS实时荧光定量聚合酶链反应（qPCR）检测（凤凰航空医学公司）和雅培sp/rt系统的检测结果进行比较。共有62/295（21%）名女性定植有GBS；标准培养法检测出58例（19.7%），而CM和qPCR分别检测出61例（20.7%）。qPCR和CM的性能相似，与常规培养相比，其灵敏度、特异性、阳性预测值和阴性预测值分别为98.4%和98.4%、99.6%和99.6%、98.4%和98.4%、99.6%和99.6%。与标准培养相比，qPCR和CM都能更快地报告常规GBS筛查结果。虽然标准培养和CM的每次检测成本相似，但qPCR的常规使用成本约为基于培养检测的四倍。世界各地的实验室应根据不同医疗保健辖区的成本限制，考虑采用一种较新的主要GBS检测方法。
