研究新型乳链菌素混合物和A型乳链菌素对幽门螺杆菌(Hp)体外杀灭作用并评估新型乳链菌素混合物的杀菌效果。

(1)实验选取Hp标准株NCTC 11637和临床株C27、临床株C28三种菌株。将相同浓度下A型乳链菌素和新型乳链菌素混合物以及空白对照组作用于Hp 2 h，培养4 d后分别记录各实验组以及空白对照组的菌群生长情况；(2)采用临界稀释法检测新型乳链菌素混合物对Hp标准株NCTC 11637和临床株的最低抑菌浓度(MIC)以及最低杀菌浓度(MBC)，采用纸片扩散法测定新型乳链菌素混合物的抑菌直径；(3)探究盐酸酸化对新型乳链菌素混合物的影响；(4)用E-test法进行抗生素药敏检测。

(1)相同浓度下，与A型乳链菌素组相比新型乳链菌素混合物组有杀菌作用；(2)新型乳链菌素混合物的MIC在不同的Hp菌株中存在差异，数值在16~32 IU/ml之间，MBC相同为32 IU/ml。新型乳链菌素混合物对Hp标准株NCTC 11647、临床株C27、临床株C28的抑菌直径在3.3 cm~3.8 cm之间；(3)盐酸酸化不影响新型乳链菌素混合物的杀菌作用；(4)新型乳链菌素混合物与四环素有协同杀灭Hp的效果，但与甲硝唑协同效果不明显。

本实验条件下新型乳链菌素混合物对Hp有良好的杀灭作用，且有良好的耐酸性，与四环素有协同杀灭Hp的效果，有望为抗生素协同疗法根治Hp感染提供新的途径。

To study the in vitro killing of Helicobacter pylori by a novel Nisin mixture and type A Nisin and to evaluate the bactericidal efficacy of the novel Nisin mixture.

(1)Three strains of Hp standard strain NCTC 11637, clinical strain C27 and clinical strain C28 were selected in the experiment.The same concentration of type A Nisin, new Nisin mixture and blank control group were applied to H. pylori for two hours, and the growth of bacteria in each experimental group and blank control group was recorded after four days of incubation; (2)The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the new nisin mixture against Hp standard strain NCTC 11637 and clinical strains were detected by critical dilution method, and the antibacterial diameter of the new nisin mixture was determined by disk diffusion method; (3)To investigate the effect of hydrochloric acid acidification on the novel Nisin mixture; (4)Antibiotic drug sensitivity testing was carried out by the E-test method.

(1)At the same concentration, the novel Nisin mixture group had a bactericidal effect compared with the type A Nisin group; (2)The MIC of novel Nisin mixture varied in different H. pylori strains, with values between 16 IU/ml to 32 IU/ml, and the MBC was the same at 32 IU/ml.the inhibitory diameters of novel Nisin mixture against Hp standard strain NCTC 11637, clinical strain C27 and clinical strain C28 ranged from 3.3 cm to 3.8 cm; (3)Hydrochloric acid acidification did not affect the bactericidal effect of novel Nisin mixture; (4)novel Nisin mixture has synergistic effect with tetracycline to kill HP, but the synergistic effect with metronidazole is not obvious.

The novel Nisin mixture has good killing effect on H. pylori under the present experimental conditions and good acid resistance, and it has synergistic effect with tetracycline to kill Hp, which is expected to provide a new way for antibiotic synergistic therapy to eradicate H. pylori infection.