南方医科大学学报 ›› 2016, Vol. 36 ›› Issue (12): 1602-.

• • 上一篇    下一篇

健康新生儿粪便中耐铅菌株的分离鉴定及铅吸附实验

沈薇,俞勤斐,王雨皓,张益多,孟晓静,范宏英   

  • 出版日期:2016-12-20 发布日期:2016-12-20

Isolation, identification and lead adsorption study of lead-resistant Lactobacillus casei strains from feces of healthy newborns

  • Online:2016-12-20 Published:2016-12-20

摘要: 目的分离、鉴定具备重金属铅抗性、铅吸附性的乳酸菌,为成为具有排铅功能的新型保健食品提供新的菌源。方法利用 乳酸菌选择性培养基MRS,从30份健康、足月新生儿粪便分离耐铅菌,通过形态特征,16S rRNA测序,构建系统发育树;利用 《伯杰氏系统细菌学手册》进行生理生化、药敏检测和耐酸耐胆盐试验;进一步通过ICP-OES法检测分离菌对铅离子的吸附能 力。结果分离得到3株可耐受500 mg/L铅离子浓度的干酪乳杆菌,均对青霉素、头孢曲松敏感。耐酸耐胆盐试验显示pH 2.0 人工胃液培养3 h,细菌数保持相同数量级,0.3%的胆盐环境8 h存活率可达62.5%。吸附实验表明对低浓度(1 mg/L)铅离子的 吸附率高达90.4%,对高浓度(50 mg/L)铅离子的吸附率可达86.27%。结论从新生儿粪便中分离到3株具备铅抗性、铅吸附性、 耐酸耐胆盐的干酪乳杆菌,为利用益生菌膳食策略缓解铅中毒效应开辟新的途径和解决方案。

Abstract: Objective To isolate and identify lead-resistant Lactobacillus casei strains with lead adsorption ability from the stool of healthy newborns as a new source of bacteria for developing lead-eliminating food products. Methods MRS was used to isolate lead-resistant bacteria from the feces of 30 healthy and full-term neonates. A phylogenetic tree was constructed based on the morphological characteristics and 16S rRNA sequences of the isolated bacteria. Physiological and biochemical characterizations of the bacteria were performed according to the Berger’s Systematic Bacteriology Handbook, followed by antimicrobial susceptibility test and acid-tolerant bile salt test. The adsorption capacity of Pb2 + of the bacteria was determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results Three strains of Lactobacillus casei were isolated, which were resistant to penicillin and ceftriaxone and could tolerate the exposure to 500 mg/L Pb2+. Acid-tolerant bile salt test showed that the bacteria were resistant to culture in the presence of artificial gastric juice (pH 2.0) for 3 h, and their survival rate reached 62.5% following exposure to 0.3% bile salt for 8 h. The bacteria showed a Pb2+ adsorption rate of 90.4% at a low Pb2 + concentration (1 mg/L) and of 86.27% at a high Pb2 + concentration (50 mg/L). Conclusion Three Lactobacillus casei strains lead adsorption ability were isolated from the feces of newborns. These bacterial strains provide a new solution to alleviate lead poisoning by probiotic dietary.