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BACKGROUND: In December 2006, we investigated an outbreak of Salmonella serotype Tennessee in a neonatal intensive care unit (NICU) that coincided with a nationwide Salmonella Tennessee outbreak associated with contaminated peanut butter. METHODS: Salmonellosis was defined as isolation of Salmonella Tennessee from any clinical specimen or more than 1 episode of bloody stool within a 24-hour period. We conducted a cohort study among 13 NICU infants, reviewed medical records, cultured stool from infants and staff, collected environmental samples, and examined infection control practices. RESULTS: Ten of the 13 infants had salmonellosis (77%). No medical or dietary risk factors were identified. The proportion of days in which the NICU census exceeded its 11-bed design capacity was higher in December compared with the previous 11 months (41.9% vs 0.3%; P < .001). Hand sinks did not meet operational standards. Salmonella Tennessee was isolated from 9 of the 13 infants, 2 of 40 staff members, and 6 of 42 environmental samples; all isolates matched the pulsed-field gel electrophoresis pattern of the nationwide Salmonella Tennessee outbreak. CONCLUSIONS: Although the source of Salmonella Tennessee was not identified, the high census and limited access to sinks likely facilitated transmission to the NICU infants. Infection control interventions, including halting new NICU admissions, interrupted further transmission. [ABSTRACT FROM AUTHOR]

Background: In 2008, children playing on a soccer field in Colorado were sickened with a strain of Shiga toxin-producing Escherichia coli (STEC) O157:H7, which was ultimately linked to feces from wild Rocky Mountain elk. We addressed whether wild cervids were a potential source of STEC infections in humans and whether STEC was ubiquitous throughout wild cervid populations in Colorado., Methodology/principal Findings: We collected 483 fecal samples from Rocky Mountain elk and mule deer in urban and non-urban areas. Samples testing positive for STEC were higher in urban (11.0%) than non-urban (1.6%) areas. Elk fecal samples in urban areas had a much higher probability of containing STEC, which increased in both urban and non-urban areas as maximum daily temperature increased. Of the STEC-positive samples, 25% contained stx1 strains, 34.3% contained stx2, and 13% contained both stx1 and stx2. Additionally, eaeA genes were detected in 54.1% of the positive samples. Serotypes O103, and O146 were found in elk and deer feces, which also have the potential to cause human illness., Conclusions/significance: The high incidence of stx2 strains combined with eaeA and E-hyl genes that we found in wild cervid feces is associated with severe human disease, such as hemolytic uremic syndrome. This is of concern because there is a very close physical interface between elk and humans in urban areas that we sampled. In addition, we found a strong relationship between ambient temperature and incidence of STEC in elk feces, suggesting a higher incidence of STEC in elk feces in public areas on warmer days, which in turn may increase the likelihood that people will come in contact with infected feces. These concerns also have implications to other urban areas where high densities of coexisting wild cervids and humans interact on a regular basis.

Thietanes were used in the past as mimics for an unstable oxetane intermediate formed during the repair of mutagenic (6-4) lesions. The thietane derivatives were found to be not repaired, raising the question of how well thietanes are cleaved by single electron donation compared to oxetanes. We have prepared two flavin-containing oxetane and thietane model compounds for the (6-4) photolyase catalyzed repair process and we show that both are efficiently cleaved by a reduced and deprotonated flavin. Thietanes are therefore excellent models. The lack of their repair can be attributed to lack of binding.

PNA:DNA strands were prepared containing a flavin electron donor and a thymine dimer acceptor, which gives a strand break upon single electron reduction. With these constructs, it was confirmed that an excess electron transfer through the base stack can be efficient in an interstrand fashion. The effect of an increased distance, a changed sequence, and stacking was explored.