Tazi A, Doloy A, Réglier-Poupet H, Hemet M-E, Raymond J, Poyart C
Faculté de Médecine, Paris-5-René Descartes, 15 Rue de l'Ecole-de-Médecine, 75270 Paris Cedex, France.
Pathol Biol (Paris). 2009 May;57(3):225-8. doi: 10.1016/j.patbio.2008.09.002. Epub 2008 Nov 12.
To compare and evaluate the new chromogenic StrepB Select (BioRad) medium to the Granada (bioMérieux) and Columbia horse blood agar plates (CH-BAP) for screening of Group B Streptococcus (GBS) vaginal colonization in pregnant women.
One hundred and ninety vaginal swabs were processed and the three media inoculated. All plates were examined after 18-24h incubation at 37 degrees C and reincubated for an additional 24h. All suspected colonies were identified as GBS by using a commercial Lancefield group-specific latex agglutination test.
GBS were isolated in 32 samples (16.8%) by at least one medium. After 24h of incubation, GBS were recovered on CH-BAP in 16 samples (50%) compared to 28 (87.5%) for StrepB Select, and 27 (84.5%) for Granada. After 48h of incubation, 30 (93.7%) out of the 32 GBS vaginal carriers were positive with CH-BAP, StrepB Select and Granada. Other streptococcal and enterococcal species gave GBS-like colonies on StrepB Select medium implying the use of other tests to confirm GBS identification. We demonstrated that direct agglutination of GBS isolated all media with Pastorex StrepB accurately identified GBS. The two StrepB Select false-negative results corresponded to a very low colonisation rate. Two Granada false-negative results corresponded to non-haemolytic and non-pigmented GBS strains which were correctly identified on StrepB Select. Both selective media inhibit the growth of associated saprophytic flora.
The use of the new StrepB Select chromogenic medium in routine laboratories may therefore markedly facilitate the rapid and accurate detection of GBS in vaginal samples.
比较并评估新型显色培养基StrepB Select（伯乐公司）与格拉纳达培养基（生物梅里埃公司）及哥伦比亚马血琼脂平板（CH - BAP）用于筛查孕妇B族链球菌（GBS）阴道定植情况的效果。
对190份阴道拭子进行处理，并接种于这三种培养基上。所有平板在37℃孵育18 - 24小时后进行检查，然后再额外孵育24小时。使用商业性的兰斯菲尔德群特异性乳胶凝集试验将所有疑似菌落鉴定为GBS。
至少一种培养基从32份样本（16.8%）中分离出GBS。孵育24小时后，CH - BAP上有16份样本（50%）检出GBS，而StrepB Select为28份（87.5%），格拉纳达培养基为27份（84.5%）。孵育48小时后，32例GBS阴道携带者中有30例（93.7%）在CH - BAP、StrepB Select和格拉纳达培养基上呈阳性。其他链球菌和肠球菌在StrepB Select培养基上形成类似GBS的菌落，这意味着需要使用其他试验来确认GBS的鉴定。我们证明，使用Pastorex StrepB对从所有培养基中分离出的GBS进行直接凝集可准确鉴定GBS。StrepB Select的两个假阴性结果对应的定植率非常低。格拉纳达培养基的两个假阴性结果对应的是在StrepB Select上被正确鉴定的非溶血性和无色素GBS菌株。两种选择性培养基均抑制相关腐生菌群的生长。
因此，在常规实验室中使用新型StrepB Select显色培养基可能会显著促进对阴道样本中GBS的快速准确检测。
