Pseudomonas fluorescens-like bacteria from the stomach: A microbiological and molecular study
Pseudomonas fluorescens-like bacteria from the stomach: A microbiological and molecular study
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DOI：
10.3748/wjg.v19.i7.1056
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发表时间：
2013-02-21
影响因子：
4.3
通讯作者：
Nath, Gopal
中科院分区：
文献类型：
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作者：
Patel, Saurabh Kumar;Pratap, Chandra Bhan;Nath, Gopal
目的：表征需氧生长的产生氧化酶和脲酶的细菌分离株，这些细菌源自酸性消化性疾病患者的胃窦活检标本。方法：对总共 258 个胃窦活检标本进行细菌分离，然后测试氧化酶和脲酶的产生、耐酸性和需氧生长。所选分离株通过分子技术进一步表征，即。使用通用真细菌和 HSP60 基因特异性引物扩增 16S rRNA。对扩增子进行限制性分析和部分测序。使用算术平均的未加权配对方法（UPGMA）根据系统发育的引导测试计算的进化距离生成系统发育树。采用10(-7) mol/L至10(-1) mol/L盐酸对胃窦分离细菌进行耐酸性评估。结果：258份患者胃窦活检标本中，快速脲酶试验179份（69.4%）产脲酶阳性，31%（80/258）产典型幽门螺杆菌（H. pylori）。 pylori）在微需氧环境下孵育5-7天后。过夜孵育后，总共 240 个（93%）胃窦活检产生均匀的半透明小菌落。部分16S rRNA序列显示分离株与假单胞菌属物种有99%的相似性。基于16S rRNA序列的系统发育树表明JQ927226和JQ927227可能与荧光假单胞菌（P. florescens）有关。根据应用于UPGMA系统发育树的HSP60序列，观察到有氧环境中分离的菌株很可能是荧光假单胞菌，并且HSP60序列比16S rRNA序列具有更强的辨别潜力。有趣的是，这种细菌在低pH值下能耐酸数小时。此外，通过靶向荧光假单胞菌特异性保守的推定外膜蛋白基因序列，258 个活检标本的总共 250 个 (96.9%) 基因组 DNA 样本和来自 240 个细菌分离株的 DNA 对 613 bp 扩增子呈阳性。幽门螺杆菌也可以在胃中定植，并可能与发病机制/保护有关。 (C)2013年百事登。版权所有。
AIM: To characterize oxidase- and urease-producing bacterial isolates, grown aerobically, that originated from antral biopsies of patients suffering from acid peptic diseases.METHODS: A total of 258 antral biopsy specimens were subjected to isolation of bacteria followed by tests for oxidase and urease production, acid tolerance and aerobic growth. The selected isolates were further characterized by molecular techniques viz. amplifications for 16S rRNA using universal eubacterial and HSP60 gene specific primers. The amplicons were subjected to restriction analysis and partial sequencing. A phylogenetic tree was generated using unweighted pair group method with arithmetic mean (UPGMA) from evolutionary distance computed with bootstrap test of phylogeny. Assessment of acidity tolerance of bacteria isolated from antrum was performed using hydrochloric acid from 10(-7) mol/L to 10(-1) mol/L.RESULTS: Of the 258 antral biopsy specimens collected from patients, 179 (69.4%) were positive for urease production by rapid urease test and 31% (80/258) yielded typical Helicobacter pylori (H. pylori) after 5-7 d of incubation under a microaerophilic environment. A total of 240 (93%) antral biopsies yielded homogeneous semi-translucent and small colonies after overnight incubation. The partial 16S rRNA sequences revealed that the isolates had 99% similarity with Pseudomonas species. A phylogenetic tree on the basis of 16S rRNA sequences denoted that JQ927226 and JQ927227 were likely to be related to Pseudomonas fluorescens (P. fluorescens). On the basis of HSP60 sequences applied to the UPGMA phylogenetic tree, it was observed that isolated strains in an aerobic environment were likely to be P. fluorescens, and HSP60 sequences had more discriminatory potential rather than 16S rRNA sequences. Interestingly, this bacterium was acid tolerant for hours at low pH. Further, a total of 250 (96.9%) genomic DNA samples of 258 biopsy specimens and DNA from 240 bacterial isolates were positive for the 613 bp amplicons by targeting P. fluorescens-specific conserved putative outer membrane protein gene sequences.CONCLUSION: This study indicates that bacterial isolates from antral biopsies grown aerobically were P. fluorescens, and thus acid-tolerant bacteria other than H. pylori can also colonize the stomach and may be implicated in pathogenesis/protection. (C) 2013 Baishideng. All rights reserved.