对口腔变异链球菌具有抑制作用的乳杆菌的筛选

Screening of Lactobacillus strains for inhibiting the oral Streptococcus mutant

拟从发酵食品与成人唾液中分离乳杆菌,并筛选出对变异链球菌具有抑制作用的菌株。利用LBS培养基从5种发酵泡菜与20名成人唾液中分离乳杆菌,采用杯碟法检测抑菌活性,通过测定菌株抑制变异链球菌(Streptococcus mutant CICC 35668)菌膜形成的能力与羟磷灰石降解能力来评价其作为潜在口腔益生菌的可能性。共分离获得了2株菌(P6,T4)对变异链球菌的抑菌圈直径为(17.44±0.85)mm与(17.82±0.74)mm,经鉴定均为植物乳杆菌;分离株可以使菌膜中变异链球菌的数量从(8.54±0.05)log cfu降至(6.14±0.17)log cfu与(6.47±0.12)log cfu;培养72 h后,对羟磷灰石的降解能力分别为(0.25±0.01)μg/mL和(0.29±0.02)μg/mL。分离获得的2株对变异链球菌具有较好抑制作用的植物乳杆菌,具有作为口腔益生菌的潜能。

The aim of the study was to isolate the Lactobacillus strains against caries pathogen Streptococcus mutant from human saliva samples and fermented food. The LBS medium was used to isolate the strains from 20 human saliva samples and 5 different pickles. The inhibitory activity of the Lactobacillus isolates was determined by Oxford cup. The effects of the Lactobacillus isolates on the formation of Streptococcus mutant biofilm and the degradation of hydroxyapatite were also determined in the study. The results showed that 2 strains （P6 and T4） that had inhibitory ability were obtained and identified as Lactobacillus plantarum. The diameter of inhabiting zones of P6 and T4 were （17.44±0.85） mm and （17.82±0.74） mm respectively. Compared with single Streptococcus mutant biofilm, the two strains P6 and T4 decreased the number of Streptococcus mutant in the biofitm from （8.54±0.05） log cfu to （6.14±0.17） log cfu and （6.47±0.12） log cfu. Both of the two strains had a significant inhibitory effect on the growth of Streptococcus mutant. At 72 h of incubation, the calcium release from hydroxyapatite caused by P6 and T4 were （0.25±0.01）μg/mL and （0.29±0.02） μg/mL, both of the two strains has a slight degradation ability. The two selected strains significantly reduced the oral carriage of Streptococcus mutant and can be used as potential oral probiotics.