UREA PROTECTS HELICOBACTER-(CAMPYLOBACTER)-PYLORI FROM THE BACTERICIDAL EFFECT OF ACID
UREA PROTECTS HELICOBACTER-(CAMPYLOBACTER)-PYLORI FROM THE BACTERICIDAL EFFECT OF ACID
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DOI：
10.1016/0016-5085(90)90957-3
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发表时间：
1990-09-01
期刊：
影响因子：
29.4
通讯作者：
GUERRANT, RL
中科院分区：
文献类型：
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作者：
MARSHALL, BJ;BARRETT, LJ;GUERRANT, RL
幽门螺杆菌（弯曲杆菌）在胃中的定植在十二指肠溃疡病患者中很常见，十二指肠溃疡病以其高酸分泌而闻名。虽然细菌通常通过培养胃活检标本来分离，但有时可在酸性胃液中发现活微生物。推测脲酶通过产生氨保护H. pylori酸为了验证这一假设，H.幽门螺杆菌，奇异变形杆菌，和尿素酶阴性空肠弯曲菌进行了检查，在存在和不存在尿素。结果表明，在不加尿素的条件下，这三种细菌对酸都是高度敏感的。与此相反，加入5 mmol/L尿素可完全保护H. pylori感染，而不感染奇异变形杆菌和C.空肠的pH值低至1.5。尿素对H. pylori检出率为0.05mmol/L。由此可见，H.幽门螺杆菌使其能够在胃酸中存活。
Colonization of the stomach with Helicobacter (Campylobacter) pylori is common in patients with duodenal ulcer disease, which is known for its high acid secretion. Although the bacterium is usually isolated by culture of a gastric biopsy specimen, viable organisms may sometimes be found in the acidic gastric juice. It was postulated that urease, by generating ammonia, protected H. pylori from acid. To test this hypothesis, the pH susceptibility of H. pylori, Proteus mirabilis, and the urease-negative Campylobacter jejuni was examined in the presence and absence of urea. It was found that without urea the three bacteria were all highly susceptible to acid. In striking contrast, the addition of 5 mmol/L of urea completely protected H. pylori but not P. mirabilis or C. jejuni from pH values as low as 1.5. Furthermore, the protective effect of urea on H. pylori was found with urea concentrations as low as 0.05 mmol/L. It is concluded that the high urease activity of H. pylori enables it to survive in gastric acid.