Urease-positive bacteria other than Helicobacter pylori in human gastric juice and mucosa
Urease-positive bacteria other than Helicobacter pylori in human gastric juice and mucosa
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DOI：
10.1111/j.1572-0241.2006.00698.x
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发表时间：
2006-08-01
影响因子：
9.8
通讯作者：
Biasco, Guido
中科院分区：
文献类型：
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作者：
Brandi, Giovanni;Biavati, Bruno;Biasco, Guido
背景与目的：人类不同生态系统中许多细菌都携带脲酶，但幽门螺杆菌是唯一已知在胃生态系统中表现出脲酶活性的细菌。因此，胃活检的快速尿素酶试验（RUT）和尿素呼气试验（C-UBT）被用来检测幽门螺杆菌感染。本研究的目的是评估胃酸过少受试者的胃液和粘膜中除幽门螺杆菌以外的脲酶阳性细菌的存在情况。方法：对 25 名胃酸过少和 10 名胃酸正常患者的胃液和粘膜中幽门螺杆菌的存在和细菌过度生长进行了分析。上午 8 点进行上消化道内窥镜检查时，从胃窦和胃体采集胃液样本和活检标本。所有样品均使用标准微生物程序进行分析，如需氧/厌氧生长、革兰氏染色、气相色谱、API 测试、96 克隆方法和选择性培养基来寻找特定细菌。此外，使用 CP 测试筛选所有分离菌株的脲酶活性。测试了脲酶阳性菌株在有或没有尿素（10 mM/L）、pH 7、4、3和2的酸性环境中不同时间（0、20、30和60分钟）的生存能力。 结果：6名胃酸过少患者中有10株脲酶阳性非幽门螺杆菌。幽门螺杆菌中，头状葡萄球菌脲酶活性最强。结论：胃酸过少患者体内除幽门螺杆菌外，还存在多种脲酶阳性菌。强烈的脲酶活性可能是疑似幽门螺杆菌感染患者的 RUT 或 UBT 检测出现假阳性结果的原因。
BACKGROUND AND AIM: Many bacteria carry the urease enzyme in different human ecosystems, but Helicobacter pylori is the only known bacterium showing urease activity in gastric ecosystems. For this reason, the rapid urease test (RUT) on gastric biopsies and urea breath test (C-UBT) are used to detect H. pylori infection. The aim of this study was to evaluate the presence of urease-positive bacteria other than H. pylori in gastric juice and mucosa in hypochlorhydric subjects.METHODS: Twenty-five hypochlorhydric and 10 normochlorhydric patients were analyzed for the presence of H. pylori and bacterial overgrowth both in gastric juice and on the mucosa. During upper gastrointestinal endoscopy at 8.00 a.m. gastric juice samples and biopsy specimens were taken from the antrum and corpus. All samples were analyzed using standard microbiological procedures like aerobic/anaerobic growth, gram-staining, gas chromatography, API test, 96-clone method, and selective medium to search for specific bacteria. In addition, all strains isolated were screened for urease activity using the CP-test. Urease positive strains were tested for the capacity to survive in an acid environment with or without urea (10 mM/L), at pH 7, 4, 3, and 2, respectively, at different times (0, 20, 30, and 60 min).RESULTS: Six hypochlorhydric patients had 10 strains of urease-positive non-H. pylori bacteria among which Staphylococcus capitis urealiticum showed the strongest urease activity.CONCLUSIONS: Hypochlorhydric patients present many urease-positive bacteria other than H. pylori. The strong urease activity may be responsible for false positive results at RUT or UBT test in patients with suspected H. pylori infection.