School of Health Care Science, Manchester Metropolitan University, Chester Street, Manchester, M1 5GD, United Kingdom.
J Microbiol Methods. 2012 Jul;90(1):65-71. doi: 10.1016/j.mimet.2012.03.015. Epub 2012 Mar 30.
This study aimed to develop a solid culture medium for differential isolation of the probiotic strain Lactobacillus casei Shirota (LcS) and for selective cultivation of lactobacilli present in oral samples. Type strains of lactobacilli and isolates from commercial probiotic products were inoculated onto modified de Man Rogosa Sharpe agar (termed 'LcS Select'), containing bromophenol blue pH indicator, vancomycin and reducing agent L-cysteine hydrochloride for differential colony morphology development. L. casei Shirota cultured on the novel medium produced distinctive colony morphologies, different from other lactobacilli tested. LcS-characteristic colonies were recovered on LcS Select medium from samples of saliva and tongue plaque following a four-week probiotic intervention study. The viable count of presumptive LcS colonies correlated with those isolated on a non-commercial lactitol-LBS-vancomycin agar (LLV) developed for a selective isolation of LcS from faeces. The novel LcS Select medium proved suitable for differential isolation of the probiotic strain L. casei Shirota from oral samples containing mixed microbial populations. It can also be used for selective growth of vancomycin-resistant lactobacilli. There are few available culture media that are sufficiently selective to enable isolation of probiotic strains from mixed populations. LcS Select medium provides a cheaper, yet effective tool in this context.
本研究旨在开发一种固体培养基，用于益生菌菌株干酪乳杆菌 Shirota（LcS）的差异分离，以及口腔样本中乳杆菌的选择性培养。将乳杆菌的模式菌株和商业益生菌产品的分离株接种到改良 de Man Rogosa Sharpe 琼脂（称为“LcS Select”）上，其中含有溴酚蓝 pH 指示剂、万古霉素和还原剂 L-半胱氨酸盐酸盐，以促进差异菌落形态的发展。在新型培养基上培养的干酪乳杆菌 Shirota 产生了独特的菌落形态，与其他测试的乳杆菌不同。在为期四周的益生菌干预研究后，从唾液和舌菌斑样本中回收了具有 LcS 特征的菌落。推定的 LcS 菌落的活菌数与在用于从粪便中选择性分离 LcS 的非商业乳糖-LBS-万古霉素琼脂（LLV）上分离的菌落数相关。新型 LcS Select 培养基证明适合从含有混合微生物群的口腔样本中差异分离益生菌菌株干酪乳杆菌 Shirota。它还可用于万古霉素抗性乳杆菌的选择性生长。很少有可用的培养基具有足够的选择性，可以从混合群体中分离出益生菌菌株。LcS Select 培养基在这种情况下提供了一种更便宜但有效的工具。
