Draft Genome Sequences of Eight Enterohepatic Helicobacter Species Isolated from Both Laboratory and Wild Rodents

The draft genome sequences of eight enterohepatic Helicobacter species, H. muridarum, H. trogontum, H. typhlonius, and five unnamed helicobacters, are presented here. Using laboratory mice pervasively infected with helicobacters, we characterized the presence of known virulence factors.National Institutes of Health (U.S.) (grant R01CA067529)National Institutes of Health (U.S.) (grant R01OD011141)National Institutes of Health (U.S.) (grant P01CA26731)National Institutes of Health (U.S.) (grant P30ES002109

Draft Genome Sequences of Six Enterohepatic Helicobacter Species Isolated from Humans and One from Rhesus Macaques

Draft genome sequences of seven enterohepatic Helicobacter species, H. bilis, H. canadensis, H. canis, H. cinaedi, H. winghamensis, H. pullorum, and H. macacae, are presented. These isolates were obtained from clinical patients and a nonhuman primate. Due to potential zoonotic risks, we characterized antibiotic resistance markers and Helicobacter virulence factors.National Institutes of Health (U.S.) (Department of Health and Human Services, under grant U54HG003067)National Human Genome Research Institute (U.S.)National Institutes of Health (U.S.) (Department of Health and Human Services, under grant R01CA067529)National Institutes of Health (U.S.) (Department of Health and Human Services, under grant R01OD011141)National Institutes of Health (U.S.) (Department of Health and Human Services, under grant P01CA26731)National Institutes of Health (U.S.) (Department of Health and Human Services, under grant P30ES002109

Draft Genome Sequences of Five Novel Polyketide Synthetase-Containing Mouse

We report herein the draft genomes of five novel Escherichia coli strains isolated from surveillance and experimental mice housed at MIT and the Whitehead Institute and describe their genomic characteristics in context with the polyketide synthetase (PKS)-containing pathogenic E. coli strains NC101, IHE3034, and A192PP.National Institutes of Health (U.S.) (P30-ES002109)National Institutes of Health (U.S.) (T32OD010978)National Institutes of Health (U.S.) (R010D0111141

Whole-Genome Sequences and Classification of

In collaboration with the CDC’s Streptococcus Laboratory, we report here the whole-genome sequences of seven Streptococcus agalactiae bacteria isolated from laboratory-reared Long-Evans rats. Four of the S. agalactiae isolates were associated with morbidity accompanied by endocarditis, metritis, and fatal septicemia, providing an opportunity for comparative genomic analysis of this opportunistic pathogen.United States. National Institutes of Health (T32-OD010978)United States. National Institutes of Health (P30-ES002109

Isolation of a Campylobacter lanienae-like Bacterium from Laboratory Chinchillas (Chinchilla laniger)

Routine necropsies of 27 asymptomatic juvenile chinchillas revealed a high prevalence of gastric ulcers with microscopic lymphoplasmacytic gastroenteritis and typhlocolitis. Polymerase chain reaction (PCR) analysis using Campylobacter genus-specific partial 16S rRNA primers revealed the presence of Campylobacter spp. DNA in the faeces of 12 of 27 animals (44.4%). Species-specific partial 16S rRNA PCR and sequencing confirmed that these animals were colonized with Campylobacter lanienae, a gram-negative, microaerophilic bacterium that was first identified on routine faecal screening of slaughterhouse employees and subsequently isolated from faeces of livestock. Campylobacter lanienae was isolated from the faeces of six PCR-positive animals and identified with species-specific PCR and full 16S rRNA sequencing. Phylogenetic analysis showed that these isolates clustered with C. lanienae strain NCTC 13004. PCR analysis of DNA extracted from gastrointestinal tissues revealed the presence of C. lanienae DNA in the caecum and colon of these chinchillas. Gastrointestinal lesions were scored and compared between C. lanienae-positive and C. lanienae-negative animals. There was no correlation between colonization status and lesion severity in the stomach, liver, duodenum, or colon. Possible routes of C. lanienae infection in chinchillas could include waterborne transmission and faecal–oral transmission from wild mice and rats or livestock. Based on these findings, the authors conclude that C. lanienae colonizes the lower bowel of chinchillas in the absence of clinical disease. This is the first report of C. lanienae in any rodent species. Campylobacter lanienae isolates from different mammalian species demonstrate heterogeneity by 16S rRNA sequence comparison. Analysis using rpoB suggests that isolates and clones currently identified as C. lanienae may represent multiple species or subspecies.Ruth L. Kirschstein National Research Service AwardNational Institutes of Health (U.S.) (Grant R01-OD011141)National Institutes of Health (U.S.) (Grant T32-OD007036)National Institutes of Health (U.S.) (Grant P30-ES02109

Bipolar lophotrichous Helicobacter suis combine extended and wrapped flagella bundles to exhibit multiple modes of motility

The swimming strategies of unipolar flagellated bacteria are well known but little is known about how bipolar bacteria swim. Here we examine the motility of Helicobacter suis, a bipolar gastric-ulcer-causing bacterium that infects pigs and humans. Phase-contrast microscopy of unlabeled bacteria reveals flagella bundles in two conformations, extended away from the body (E) or flipped backwards and wrapped (W) around the body. We captured videos of the transition between these two states and observed three different swimming modes in broth: with one bundle rotating wrapped around the body and the other extended (EW), both extended (EE), and both wrapped (WW). Only EW and WW modes were seen in porcine gastric mucin. The EW mode displayed ballistic trajectories while the other two displayed superdiffusive random walk trajectories with slower swimming speeds. Separation into these two categories was also observed by tracking the mean square displacement of thousands of trajectories at lower magnification. Using the Method of Regularized Stokeslets we numerically calculate the swimming dynamics of these three different swimming modes and obtain good qualitative agreement with the measurements, including the decreased speed of the less frequent modes. Our results suggest that the extended bundle dominates the swimming dynamics

MyD88 signalling in colonic mononuclear phagocytes drives colitis in IL-10-deficient mice

Commensal bacterial sensing by Toll-like receptors is critical for maintaining intestinal homeostasis, but can lead to colitis in the absence of interleukin-10. Although Toll-like receptors are expressed in multiple cell types in the colon, the cell type(s) responsible for the development of colitis are currently unknown. Here we generated mice that are selectively deficient in MyD88 in various cellular compartments in an interleukin-10[superscript −/−] setting. Although epithelial expression of MyD88 was dispensable, MyD88 expression in the mononuclear phagocyte compartment was required for colitis development. Specifically, phenotypically distinct populations of colonic mononuclear phagocytes expressed high levels of interleukin-1β, interleukin-23 and interleukin-6, and promoted T-helper 17 responses in the absence of interleukin-10. Thus, gut bacterial sensing through MyD88 in mononuclear phagocytes drives inflammatory bowel disease when unopposed by interleukin-10.Howard Hughes Medical InstituteNational Institutes of Health (U.S.) (NIH grant DK071754)National Institutes of Health (U.S.) (NIH grant AI046688)National Institutes of Health (U.S.) (NIH grant AI055502)National Institutes of Health (U.S.) (NIH grant RO1OD011141)National Institutes of Health (U.S.) (Training grant)National Cancer Institute (U.S.) (Irvington Fellowship

Lamellipodin-Deficient Mice: A Model of Rectal Carcinoma

During a survey of clinical rectal prolapse (RP) cases in the mouse population at MIT animal research facilities, a high incidence of RP in the lamellipodin knock-out strain, C57BL/6-Raph1[superscript tm1Fbg] (Lpd[superscript -/-]) was documented. Upon further investigation, the Lpd[superscript -/-] colony was found to be infected with multiple endemic enterohepatic Helicobacter species (EHS). Lpd[superscript -/-] mice, a transgenic mouse strain produced at MIT, have not previously shown a distinct immune phenotype and are not highly susceptible to other opportunistic infections. Predominantly male Lpd[superscript -/-] mice with RP exhibited lesions consistent with invasive rectal carcinoma concomitant to clinically evident RP. Multiple inflammatory cytokines, CD11b+Gr1+ myeloid-derived suppressor cell (MDSC) populations, and epithelial cells positive for a DNA damage biomarker, H2AX, were elevated in affected tissue, supporting their role in the neoplastic process. An evaluation of Lpd[superscript -/-] mice with RP compared to EHS-infected, but clinically normal (CN) Lpd[superscript -/-] animals indicated that all of these mice exhibit some degree of lower bowel inflammation; however, mice with prolapses had significantly higher degree of focal lesions at the colo-rectal junction. When Helicobacter spp. infections were eliminated in Lpd[superscript -/-] mice by embryo transfer rederivation, the disease phenotype was abrogated, implicating EHS as a contributing factor in the development of rectal carcinoma. Here we describe lesions in Lpd[superscript -/-] male mice consistent with a focal inflammation-induced neoplastic transformation and propose this strain as a mouse model of rectal carcinoma.United States. National Institutes of Health (T32-OD010978)United States. National Institutes of Health (R01-OD011141)United States. National Institutes of Health (P30-ES002109)Massachusetts Institute of Technology. Ludwig Center for Molecular Oncology (U54- CA114462)National Cancer Institute (U.S.) (P30-CA14051

Enterohepatic Helicobacter in ulcerative colitis:Potential pathogenic entities?

Background: Changes in bacterial populations termed "dysbiosis" are thought central to ulcerative colitis (UC) pathogenesis. In particular, the possibility that novel Helicobacter organisms play a role in human UC has been debated but not comprehensively investigated. The aim of this study was to develop a molecular approach to investigate the presence of Helicobacter organisms in adults with and without UC.Methodology/Principal Findings: A dual molecular approach to detect Helicobacter was developed. Oligonucleotide probes against the genus Helicobacter were designed and optimised alongside a validation of published H. pylori probes. A comprehensive evaluation of Helicobacter genus and H. pylori PCR primers was also undertaken. The combined approach was then assessed in a range of gastrointestinal samples prior to assessment of a UC cohort. Archival colonic samples were available from 106 individuals for FISH analysis (57 with UC and 49 non-IBD controls). A further 118 individuals were collected prospectively for dual FISH and PCR analysis (86 UC and 32 non-IBD controls). An additional 27 non-IBD controls were available for PCR analysis. All Helicobacter PCR-positive samples were sequenced. The association between Helicobacter and each study group was statistically analysed using the Pearson Chi Squared 2 tailed test. Helicobacter genus PCR positivity was significantly higher in UC than controls (32 of 77 versus 11 of 59, p = 0.004). Sequence analysis indicated enterohepatic Helicobacter species prevalence was significantly higher in the UC group compared to the control group (30 of 77 versus 2 of 59, p&lt;0.0001). PCR and FISH results were concordant in 74 (67.9%) of subjects. The majority of discordant results were attributable to a higher positivity rate with FISH than PCR.Conclusions/Significance: Helicobacter organisms warrant consideration as potential pathogenic entities in UC. Isolation of these organisms from colonic tissue is needed to enable interrogation of pathogenicity against established criteria.</p

Mist1 Expressing Gastric Stem Cells Maintain the Normal and Neoplastic Gastric Epithelium and Are Supported by a Perivascular Stem Cell Niche

The regulation and stem cell origin of normal and neoplastic gastric glands are uncertain. Here, we show that Mist1 expression marks quiescent stem cells in the gastric corpus isthmus. Mist1+ stem cells serve as a cell-of-origin for intestinal-type cancer with the combination of Kras and Apc mutation and for diffuse-type cancer with the loss of E-cadherin. Diffuse-type cancer development is dependent on inflammation mediated by Cxcl12+ endothelial cells and Cxcr4+ gastric innate lymphoid cells (ILCs). These cells form the perivascular gastric stem cell niche, and Wnt5a produced from ILCs activates RhoA to inhibit anoikis in the E-cadherin-depleted cells. Targeting Cxcr4, ILCs, or Wnt5a inhibits diffuse-type gastric carcinogenesis, providing targets within the neoplastic gastric stem cell niche