Molecular characterization of the stomach microbiota in patients with gastric cancer and in controls

• Published in: Journal of medical microbiology Vol. 58; no. 4; pp. 509 - 516
• Main Authors: Dicksved, Johan, Lindberg, Mathilda, Rosenquist, Magnus, Enroth, Helena, Jansson, Janet K, Engstrand, Lars
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.04.2009; Society for General Microbiology
• Subjects: 54; 58; ABUNDANCE; Actinobacteria; Aged; Aged, 80 and over; Bacteria - classification; Bacteria - genetics; Bacteria - isolation & purification; Biological and medical sciences; CAPACITY; Case-Control Studies; CLONING; Cloning, Molecular; DNA, Bacterial - chemistry; Female; Firmicutes; Fundamental and applied biological sciences. Psychology; GASTRIC ACID; Gene Library; GENES; Helicobacter pylori; Humans; Infectious diseases; INFLAMMATION; LACTOBACILLUS; Male; Medical sciences; MEDICIN; Medicin och hälsovetenskap; MEDICINE; Microbiology; Microbiology in the medical area; Middle Aged; Mikrobiologi inom det medicinska området; MUCOUS MEMBRANES; NEOPLASMS; PATIENTS; Phylogeny; Polymorphism, Restriction Fragment Length; Prevotella; PROLIFERATION; Proteobacteria; RNA, Ribosomal, 16S - genetics; SECRETION; STOMACH; Stomach - microbiology; Stomach Neoplasms - microbiology; STREPTOCOCCUS; Tumors; Veillonella; Human; Stomach; Microbiology; Digestive system; Digestive diseases; Microflora; Malignant tumor; Stomach cancer; Cancer; Gastric disease
• ISSN: 0022-2615; 1473-5644; 1473-5644
• DOI: 10.1099/jmm.0.007302-0

1 Department of Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden 2 Swedish Institute for Infectious Disease Control, 171 82 Solna, Sweden 3 Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77 Stockholm, Sweden 4 Department of Oncology, Radiology and Clinical Immunology, Uppsala University Hospital, 751 85 Uppsala, Sweden 5 Department of Clinical Microbiology, Unilabs AB, Kärnsjukhuset, Skövde, Sweden 6 Lawrence Berkeley National Laboratory, Division of Earth Sciences, Berkeley, CA, USA Correspondence Lars Engstrand lars.engstrand{at}smi.ki.se Received October 13, 2008 Accepted December 11, 2008 Persistent infection of the gastric mucosa by Helicobacter pylori can initiate an inflammatory cascade that progresses into atrophic gastritis, a condition associated with reduced capacity for secretion of gastric acid and an increased risk of developing gastric cancer. The role of H. pylori as an initiator of inflammation is evident but the mechanism for development into gastric cancer has not yet been proven. A reduced capacity for gastric acid secretion allows survival and proliferation of other microbes that normally are killed by the acidic environment. It has been postulated that some of these species may be involved in the development of gastric cancer; however, their identities are poorly defined. In this study, the gastric microbiota from ten patients with gastric cancer was characterized and compared with that from five dyspeptic controls using the molecular profiling approach terminal restriction fragment length polymorphism (T-RFLP), in combination with 16S rRNA gene cloning and sequencing. T-RFLP analysis revealed a complex bacterial community in the cancer patients that was not significantly different from that in the controls. Sequencing of 140 clones revealed 102 phylotypes, with representatives from five bacterial phyla ( Firmicutes , Bacteroidetes , Proteobacteria , Actinobacteria and Fusobacteria ). The data revealed a relatively low abundance of H. pylori and showed that the gastric cancer microbiota was instead dominated by different species of the genera Streptococcus , Lactobacillus , Veillonella and Prevotella . The respective role of these species in development of gastric cancer remains to be determined. Abbreviations: T-RFLP, terminal restriction fragment length polymorphism; TRF, terminal restriction fragment. The GenBank/EMBL/DDBJ accession numbers for the unique sequences generated in this study are FJ268879–FJ268953.