Metabolic interplay between Proteus mirabilis and Enterococcus faecalis facilitates polymicrobial biofilm formation and invasive disease

Polymicrobial biofilms play an important role in the development and pathogenesis of CAUTI. Proteus mirabilis and Enterococcus faecalis are common CAUTI pathogens that persistently co-colonize the catheterized urinary tract and form biofilms with increased biomass and antibiotic resistance. In this study, we uncover the metabolic interplay that drives biofilm enhancement and examine the contribution to CAUTI severity. Through compositional and proteomic biofilm analyses, we determined that the increase in biofilm biomass stems from an increase in the protein fraction of the polymicrobial biofilm matrix. We further observed an enrichment in proteins associated with ornithine and arginine metabolism in polymicrobial biofilms compared to single-species biofilms. We show that L-ornithine secretion by E. faecalis promotes arginine biosynthesis in P. mirabilis, and that disruption of this metabolic interplay abrogates the biofilm enhancement we see in vitro and leads to significant decreases in infection severity and dissemination in a murine CAUTI model.

The impact of television public service announcements on the rate of bystander CPR

OBJECTIVE

To determine whether televised public service announcements (PSAs) demonstrating the fundamentals of CPR were effective in increasing the rate of layperson bystander-initiated CPR.

METHODS

Two 30-second PSAs were shown 597 times from September 8, 1996, through April 12, 1997. In each, CPR was given to one member of an older couple by the other in the home. The authors measured rates of bystander CPR in communities that were exposed to the PSA and in communities that were not exposed in two time periods, a before-airing period, January 1, 1993, through September 7, 1996, and a during-airing period, September 8, 1996, through April 12, 1997. A case was defined as a patient with a nontraumatic cardiac arrest that occurred before arrival of EMS personnel, and for whom CPR was initiated by EMS personnel or lay bystanders.

RESULTS

There were 1,786 cardiac arrests in the "before" period and 289 in the "during" period. The rate of bystander CPR increased from 43% to 55% (p<0.05) in the intervention community and remained the same in the comparison community (33%).

CONCLUSION

Airing of the PSA was accompanied by an increase in the rate of bystander CPR, though the increase may be attributable to a secular trend.

Neurotactin, a membrane-anchored chemokine upregulated in brain inflammation

Chemokines are small secreted proteins that stimulate the directional migration of leukocytes and mediate inflammation. During screening of a murine choroid plexus complementary DNA library, we identified a new chemokine, designated neurotactin. Unlike other chemokines, neurotactin has a unique cysteine pattern, Cys-X-X-X-Cys, and is predicted to be a type 1 membrane protein. Full-length recombinant neurotactin is localized on the surface of transfected 293 cells. Recombinant neurotactin containing the chemokine domain is chemotactic for neutrophils both in vitro and in vivo. Neurotactin messenger RNA is predominantly expressed in normal murine brain and its protein expression in activated brain microglia is upregulated in mice with experimental autoimmune encephalomyelitis, as well as in mice treated with lipopolysaccharide. Distinct from all other chemokine genes, the neurotactin gene is localized to human chromosome 16q. Consequently we propose that neurotactin represents a new delta-chemokine family and that it may play a role in brain inflammation processes.