Variability in the Occupancy of O157 Integration Sites by Shiga Toxin-Encoding Prophages.

O157:H7 strains often produce Shiga toxins encoded by genes on lambdoid bacteriophages that insert into multiple loci as prophages. O157 strains were classified into distinct clades that vary in virulence. Herein, we used PCR assays to examine Shiga toxin (Stx) prophage occupancy in , , , and among 346 O157 strains representing nine clades.

Metatranscriptome of human faecal microbial communities in a cohort of adult men.

The gut microbiome is intimately related to human health, but it is not yet known which functional activities are driven by specific microorganisms' ecological configurations or transcription. We report a large-scale investigation of 372 human faecal metatranscriptomes and 929 metagenomes from a subset of 308 men in the Health Professionals Follow-Up Study. We identified a metatranscriptomic 'core' universally transcribed over time and across participants, often by different microorganisms.

Stability of the human faecal microbiome in a cohort of adult men.

Characterizing the stability of the gut microbiome is important to exploit it as a therapeutic target and diagnostic biomarker. We metagenomically and metatranscriptomically sequenced the faecal microbiomes of 308 participants in the Health Professionals Follow-Up Study. Participants provided four stool samples-one pair collected 24-72 h apart and a second pair ~6 months later.

Fluoride Depletes Acidogenic Taxa in Oral but Not Gut Microbial Communities in Mice.

Fluoridation of drinking water and dental products prevents dental caries primarily by inhibiting energy harvest in oral cariogenic bacteria (such as and ), thus leading to their depletion. However, the extent to which oral and gut microbial communities are affected by host fluoride exposure has been underexplored. In this study, we modeled human fluoride exposures to municipal water and dental products by treating mice with low or high levels of fluoride over a 12-week period.

Correlation between in vivo biofilm formation and virulence gene expression in Escherichia coli O104:H4.

The emergence of novel pathogens poses a major public health threat causing widespread epidemics in susceptible populations. The Escherichia coli O104:H4 strain implicated in a 2011 outbreak in northern Germany caused the highest frequency of hemolytic uremic syndrome (HUS) and death ever recorded in a single E. coli outbreak.

Shiga toxin 2 overexpression in Escherichia coli O157:H7 strains associated with severe human disease.

Variation in disease severity among Escherichia coli O157:H7 infections may result from differential expression of Shiga toxin 2 (Stx2). Eleven strains belonging to four prominent phylogenetic clades, including clade 8 strains representative of the 2006 U.S.

Increased adherence and expression of virulence genes in a lineage of Escherichia coli O157:H7 commonly associated with human infections.

Background: Enterohemorrhagic Escherichia coli (EHEC) O157:H7, a food and waterborne pathogen, can be classified into nine phylogenetically distinct lineages, as determined by single nucleotide polymorphism genotyping. One lineage (clade 8) was found to be associated with hemolytic uremic syndrome (HUS), which can lead to kidney failure and death in some cases, particularly young children. Another lineage (clade 2) differs considerably in gene content and is phylogenetically distinct from clade 8, but caused significantly fewer cases of HUS in a prior study.

Differences in adherence and virulence gene expression between two outbreak strains of enterohaemorrhagic Escherichia coli O157 : H7.

The Escherichia coli O157 : H7 TW14359 strain was implicated in a multi-state outbreak in North America in 2006, which resulted in high rates of severe disease. Similarly, the O157 : H7 RIMD0509952 (Sakai) strain caused the largest O157 : H7 outbreak to date. Both strains were shown to represent divergent phylogenetic lineages.

Genomic diversity of pathogenic Escherichia coli of the EHEC 2 clonal complex.

Background: Evolutionary analyses of enterohemorrhagic Escherichia coli (EHEC) have identified two distantly related clonal groups: EHEC 1, including serotype O157:H7 and its inferred ancestor O55:H7; and EHEC 2, comprised of several serogroups (O26, O111, O118, etc.). These two clonal groups differ in their virulence and global distribution.