Clostridium septicum aortitis: A kiss of the devil.

BACKGROUND: Clostridium septicum aortitis is a lethal infection. C. septicum has a strong association with an underlying malignancy, most commonly in the colon. AIM: Early identification methods and management strategies of C. Septicum infection. MATERIALS AND METHODS: We present a 64-year-old man with aortic aneurysm and C. septicum bacteremia with unknown malignancy who passed away on the fourth day of hospitalization despite emergent endovascular intervention. Computed tomography showed periaortic gas which is the hallmark of infection. DISCUSSION: This case report highlights the need of prompt surgical treatment and its different modalities along with the early use of appropriate antibiotics due to the rapid spread of infection associated with high fatality. The authors also discuss the association of C. septicum aortitis with underlying occult malignancies. CONCLUSION: Delay in identification and treatment of C. Septicum is associated with very high mortality rates.

Determination and application of empirically derived detergent phase boundaries to effectively crystallize membrane proteins.

Elucidating the structures of membrane proteins is essential to our understanding of disease states and a critical component in the rational design of drugs. Structural characterization of a membrane protein begins with its detergent solubilization from the lipid bilayer and its purification within a functionally stable protein-detergent complex (PDC). Crystallization of the PDC typically occurs by changing the solution environment to decrease solubility and promote interactions between exposed hydrophilic surface residues. As membrane proteins have been observed to form crystals close to the phase separation boundaries of the detergent used to form the PDC, knowledge of these boundaries under different chemical conditions provides a foundation to rationally design crystallization screens. We have carried out dye-based detergent phase partitioning studies using different combinations of 10 polyethylene glycols (PEG), 11 salts, and 11 detergents to generate a significant amount of chemically diverse phase boundary data. The resulting curves were used to guide the formulation of a 1536-cocktail crystallization screen for membrane proteins. We are making both the experimentally derived phase boundary data and the 1536 membrane screen available through the high-throughput crystallization facility located at the Hauptman-Woodward Institute. The phase boundary data have been packaged into an interactive Excel spreadsheet that allows investigators to formulate grid screens near a given phase boundary for a particular detergent. The 1536 membrane screen has been applied to 12 membrane proteins of unknown structures supplied by the structural genomics and structural biology communities, with crystallization leads for 10/12 samples and verification of one crystal using X-ray diffraction.