不同培养基及B族链球菌增菌肉汤检测B族链球菌效果评价

doi:10.3969/j.issn.1673-8640.2015.09.006

摘要/Abstract

摘要： 目的

通过分析B族链球菌(GBS)检测的阳性检出率和平板选择性能来评价GBS筛查培养基、哥伦比亚血琼脂培养基和GBS增菌肉汤检测结果的可靠性和临床应用的可行性。

方法

收集妊娠晚期35~37周孕妇阴道下端及肛周样本242例、中段尿样本15例,同时直接接种及经GBS增菌肉汤增菌后接种哥伦比亚血平板和GBS筛查平板,观察各培养基上GBS的生长情况。

结果

直接接种后分别培养24 h和48 h,哥伦比亚血琼脂培养基GBS的检出率均为7.39%(19/257);而GBS筛查培养基的检出率为24 h 5.45%(14/257)、48 h 7.39%(19/257)。经GBS增菌肉汤增菌后,无论培养时间是24 h还是48 h,哥伦比亚血琼脂培养基GBS的检出率均为9.73%(25/257);GBS筛查培养基的检出率均为8.95%(23/257)。与直接接种相比,选择性增菌后GBS的检出率明显升高;2种培养基GBS的检出率差异无统计学意义(P>0.05)。

结论

临床样本先经GBS增菌肉汤18~24 h增菌后再接种至GBS筛查培养基或哥伦比亚血琼脂培养基,24 h即可观察生长结果,GBS 菌落易于辨认且提高了阳性检出率。

关键词: B族链球菌, B族链球菌筛查培养基, 哥伦比亚血琼脂培养基, B族链球菌增菌肉汤, 阳性检出率

Abstract: Objective

To evaluate the reliability of Group B Streptococcus(GBS) screening medium, Colombia blood agar medium and GBS enrichment broth detection results and investigate the viability of clinical application by analyzing the positive rate of GBS and the performance of selective plates.

Methods

A total of 242 samples from distal vaginal segment and around crissum and 15 midstream urine samples were collected among 35-37-week pregnant women. The samples were inoculated directly and with one more step of GBS enrichment broth on Colombia blood agar and GBS screening media, respectively, and the growth of GBS in the 2 kinds of media was observed.

Results

As for inoculating directly, the detection rates of GBS in Colombia blood agar medium for 24 h and 48 h were 7.39% (19/257), and the 24 h and 48 h detection rates of GBS in GBS screening medium were 5.45%(14/257) and 7.39%(19/257), respectively. As for inoculating with one more step of GBS enrichment broth, for neither 24 h nor 48 h, the detection rate of GBS in Colombia blood agar medium was 9.73%(25/257), and the detection rate in GBS screening medium was 8.95%(23/257), both of which had an evident increasing comparing with the former one. There was no statistical significance for the detection rate between the 2 kinds of media (P>0.05).

Conclusions

By enriching 18 h-24 h in GBS enrichment broth, followed by inoculating in GBS screening medium or Colombia blood agar medium, the growth of GBS from clinical samples in media could be observed just after 24 h, and this method has simple recognition ability for GBS and can improve GBS positive detection rate.

Key words: Group B Streptococcus, Group B Streptococcus screening medium, Colombia blood agar medium, Group B Streptococcus enrichment broth, Positive detection rate

中图分类号:

R378.1

陆庭嫣, 沈俐, 唐振华. 不同培养基及B族链球菌增菌肉汤检测B族链球菌效果评价[J]. 检验医学, 2015, 30(9): 890-893.

LU Tingyan, SHEN Li, TANG Zhenhua. Evaluation on the efficiency of different media and GBS enrichment broth for GBS detection[J]. Laboratory Medicine, 2015, 30(9): 890-893.

图/表 4

参考文献 11

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培养基种类	质控菌株	24 h结果
GBS增菌肉汤	无乳链球菌NCTC8190	生长
	大肠埃希菌 ATCC 25922	抑制
GBS筛查培养基	无乳链球菌ATCC 12386	粉色至红色菌落
	大肠埃希菌 ATCC 25922	抑制
	金黄色葡萄球菌ATCC 6538	抑制
	白念珠菌ATCC 10231	抑制
哥伦比亚血琼脂培养基	无乳链球菌NCTC8190	生长
	大肠埃希菌 ATCC 25922	生长
	金黄色葡萄球菌ATCC 6538	生长
	白色念珠菌ATCC 10231	生长

培养基种类	质控菌株	24 h结果
GBS增菌肉汤	无乳链球菌NCTC8190	生长
	大肠埃希菌 ATCC 25922	抑制
GBS筛查培养基	无乳链球菌ATCC 12386	粉色至红色菌落
	大肠埃希菌 ATCC 25922	抑制
	金黄色葡萄球菌ATCC 6538	抑制
	白念珠菌ATCC 10231	抑制
哥伦比亚血琼脂培养基	无乳链球菌NCTC8190	生长
	大肠埃希菌 ATCC 25922	生长
	金黄色葡萄球菌ATCC 6538	生长
	白色念珠菌ATCC 10231	生长

方法	培养时间(h)	非目标菌群生长密度(%)
方法	培养时间(h)	0	1	2	3	4
直接接种	24	59.6	11.5	21.3	7.1	0.5
	48	19.1	5.6	37.1	33.1	5.1
GBS增菌肉汤增菌	24	20.9	0	10.2	32.2	36.7
	48	11.1	1.2	13.5	28.7	45.6

方法	培养时间(h)	非目标菌群生长密度(%)
方法	培养时间(h)	0	1	2	3	4
直接接种	24	59.6	11.5	21.3	7.1	0.5
	48	19.1	5.6	37.1	33.1	5.1
GBS增菌肉汤增菌	24	20.9	0	10.2	32.2	36.7
	48	11.1	1.2	13.5	28.7	45.6