Invasive properties, adhesion patterns and phylogroup profiles among Escherichia coli strains isolated from children with inflammatory bowel disease.

Background: A great deal of evidence indicates a link between Escherichia coli (E. coli) and Crohn's disease in adult patients, but there is lack of information on the association of these bacilli with inflammatory bowel disease (IBD) among children.

Objectives: The study was carried out to determine the distribution of phylogenetic group, the adherence patterns and invasive properties of E.

Association of untypeable enteropathogenic Escherichia coli (EPEC) strains with persistent diarrhea in children from the region of lower Silesia in Poland.

Enteropathogenic Escherichia coli strains (EPEC) carrying the eae gene encoding intimin are divided into typical strains producing bundle forming pili, encoded by the bfpA gene, and atypical strains lacking the gene. In the study typical and atypical EPEC that did not agglutinated with EPEC polyvalent antisera but carrying virulence factors characteristic to other pathogenic E. coli i.

Cytotoxic T-lymphocyte escape mutations identified by HLA association favor those which escape and revert rapidly.

Identifying human immunodeficiency virus (HIV) immune escape mutations has implications for understanding the impact of host immunity on pathogen evolution and guiding the choice of vaccine antigens. One means of identifying cytotoxic-T-lymphocyte (CTL) escape mutations is to search for statistical associations between mutations and host human leukocyte antigen (HLA) class I alleles at the population level. The impact of evolutionary rates on the strength of such associations is not well defined.

Phylogenetic analysis consistent with a clinical history of sexual transmission of HIV-1 from a single donor reveals transmission of highly distinct variants.

Background: To combat the pandemic of human immunodeficiency virus 1 (HIV-1), a successful vaccine will need to cope with the variability of transmissible viruses. Human hosts infected with HIV-1 potentially harbour many viral variants but very little is known about viruses that are likely to be transmitted, or even if there are viral characteristics that predict enhanced transmission in vivo. We show for the first time that genetic divergence consistent with a single transmission event in vivo can represent several years of pre-transmission evolution.

Characterization of genes associated with internalization of enteroaggregative Escherichia coli.

On animal models enteroaggregative Escherichia coli (EAEC) can cause mild, but significant mucosal damage, suggesting the invasive capability of these strains. In the study we investigated the ability of typical, aggR-positive and atypical, aggR-negative EAEC isolates to enter intestinal epithelial Int407 cells in relation to the distribution of genes encoding the putative invasins described among pathogenic E. coli categories.

Modelling the evolution and spread of HIV immune escape mutants.

During infection with human immunodeficiency virus (HIV), immune pressure from cytotoxic T-lymphocytes (CTLs) selects for viral mutants that confer escape from CTL recognition. These escape variants can be transmitted between individuals where, depending upon their cost to viral fitness and the CTL responses made by the recipient, they may revert. The rates of within-host evolution and their concordant impact upon the rate of spread of escape mutants at the population level are uncertain.

Ancient urbanization predicts genetic resistance to tuberculosis.

A link between urban living and disease is seen in recent and historical records, but the presence of this association in prehistory has been difficult to assess. If the transition to urban living does result in an increase in disease-based mortality, we might expect to see evidence of increased disease resistance in longer-term urbanized populations, as the result of natural selection. To test this, we determined the frequency of an allele (SLC11A1 1729 + 55del4) associated with natural resistance to intracellular pathogens such as tuberculosis and leprosy.

Adaptation of HIV-1 to human leukocyte antigen class I.

The rapid and extensive spread of the human immunodeficiency virus (HIV) epidemic provides a rare opportunity to witness host-pathogen co-evolution involving humans. A focal point is the interaction between genes encoding human leukocyte antigen (HLA) and those encoding HIV proteins. HLA molecules present fragments (epitopes) of HIV proteins on the surface of infected cells to enable immune recognition and killing by CD8(+) T cells; particular HLA molecules, such as HLA-B*57, HLA-B*27 and HLA-B*51, are more likely to mediate successful control of HIV infection.