Shiga-Toxin-Producing Strains of Escherichia coli O104:H4 and a Strain of O157:H7, Which Can Cause Human Hemolytic Uremic Syndrome, Differ in Biofilm Formation in the Presence of CO2 and in Their Ability to Grow in a Novel Cell Culture Medium.

One pathogen that commonly causes gastrointestinal illnesses from the consumption of contaminated food is Escherichia coli O157:H7. In 2011 in Germany, however, there was a prominent outbreak of bloody diarrhea with a high incidence of hemolytic uremic syndrome (HUS) caused by an atypical, more virulent E. coli O104:H4 strain. To facilitate the identification of this lesser-known, atypical E. coli O104:H4 strain, we wanted to identify phenotypic differences between it and a strain of O157:H7 in different media and culture conditions. We found that E. coli O104:H4 strains produced considerably more biofilm than the strain of O157:H7 at 37 °C (p = 0.0470-0.0182) Biofilm production was significantly enhanced by the presence of 5% CO2 (p = 0.0348-0.0320). In our study on the innate immune response to the E. coli strains, we used HEK293 cells that express Toll-like receptors (TLRs) 2 or 4. We found that E. coli O104:H4 strains had the ability to grow in a novel HEK293 cell culture medium, while the E. coli O157:H7 strain could not. Thus, we uncovered previously unknown phenotypic properties of E. coli O104:H4 to further differentiate this pathogen from E. coli O157:H7.

Evidence of Ebola Virus Replication and High Concentration in Semen of a Patient During Recovery.

In one patient over time, we found that concentration of Ebola virus RNA in semen during recovery is remarkably higher than blood at peak illness. Virus in semen is replication-competent with no change in viral genome over time. Presence of sense RNA suggests replication in cells present in semen.

Detection of Ebola Virus RNA Through Aerosol Sampling of Animal Biosafety Level 4 Rooms Housing Challenged Nonhuman Primates.

Ebola virus disease is a serious illness of humans and nonhuman primates (NHPs). Direct contact has been shown to be the primary source of Ebola (EBOV) transmission. We used a high-volume air sampler to determine whether EBOV could be detected during 3 independent studies with EBOV-challenged NHPs. Viral RNA was recovered during days 9 and 10 of Study I and days 7 and 8 of Study III. Viral RNA levels were below limits of detection during all other collections. The results demonstrate that the biosafety level 4 (BSL-4) suit protects workers from aerosols in a BSL-4 environment using proper engineering and administrative controls.