Specificity of catecholamine-induced growth in Escherichia coli O157:H7, Salmonella enterica and Yersinia enterocolitica

The present study demonstrates that catecholamine responsiveness in Yersinia enterocolitica, a bacterial pathogen whose infectious spectrum is principally limited to the gut, is limited to norepinephrine and dopamine, and not epinephrine; this behavior contrasts with observations for two pathogens with a wider extra-gastrointestinal spectrum, Escherichia coli O157:H7 and Salmonella enterica, which respond to all three catecholamines. Epinephrine showed lower potency than norepinephrine and dopamine in inducing growth of E. coli and S. enterica, and was a potent antagonist of norepinephrine and dopamine growth responsiveness in Y. enterocolitica. Given that only norepinephrine and dopamine and not epinephrine containing neurons are found with the enteric nervous system, our results suggest that certain of the more exclusive enteric pathogens may have developed response systems preferentially for those neuroendocrine hormones that are produced by the enteric nervous system as host-derived signals by which to sense the environment and initiate pathogenic processes

Microbial endocrinology: how stress influences susceptability to infection

Microbial endocrinology: how stress influences susceptability to infectio

Increased blood levels of IgG reactive with secreted Streptococcus pyogenes proteins in chronic plaque psoriasis.

A pathogenic role for Streptococcus pyogenes infections in chronic plaque psoriasis is suspected but poorly defined. We separated cellular and supernatant proteins from S pyogenes cultures by high-resolution two-dimensional gel electrophoresis, and used immunoblotting to demonstrate the diversity of serum or plasma IgGs that react with elements of the proteome of this bacterium. We have shown that a substantial proportion of IgG-reactive proteins from cultured S pyogenes are secreted. The total secreted protein fraction, including diverse IgG-binding elements, was subsequently used in an ELISA to measure blood titers of reactive IgG. This ELISA showed that blood samples from patients with chronic plaque psoriasis contained significantly higher titers of reactive IgG than samples from age- and sex-matched healthy controls (p = 0.0009). In contrast, neither a standard assay measuring antistreptolysin O titers nor ELISAs measuring titers of IgG reactive with protein fractions from Staphylococcus aureus and Staphylococcus epidermidis, were able to distinguish between blood samples from the two groups. These findings justify the hypothesis that S pyogenes infections are more important in the pathogenesis of chronic plaque psoriasis than has previously been recognised, and indicate the need for further controlled therapeutic trials of antibacterial measures in this common skin disease