Vibriosis, not cholera: toxigenic Vibrio cholerae non-O1, non-O139 infections in the United States, 1984-2014.

Toxigenic strains of Vibrio cholerae serogroups O1 and O139 have caused cholera epidemics, but other serogroups - such as O75 or O141 - can also produce cholera toxin and cause severe watery diarrhoea similar to cholera. We describe 31 years of surveillance for toxigenic non-O1, non-O139 infections in the United States and map these infections to the state where the exposure probably originated. While serogroups O75 and O141 are closely related pathogens, they differ in how and where they infect people. Oysters were the main vehicle for O75 infection. The vehicles for O141 infection include oysters, clams, and freshwater in lakes and rivers. The patients infected with serogroup O75 who had food traceback information available ate raw oysters from Florida. Patients infected with O141 ate oysters from Florida and clams from New Jersey, and those who only reported being exposed to freshwater were exposed in Arizona, Michigan, Missouri, and Texas. Improving the safety of oysters, specifically, should help prevent future illnesses from these toxigenic strains and similar pathogenic Vibrio species. Post-harvest processing of raw oysters, such as individual quick freezing, heat-cool pasteurization, and high hydrostatic pressurization, should be considered.

Large-scale expression, refolding, and purification of the catalytic domain of human macrophage metalloelastase (MMP-12) in Escherichia coli.

We have cloned, overexpressed, and purified the catalytic domain (residues Gly106 to Asn268) of human macrophage metalloelastase (MMP-12) in Escherichia coli. This construct represents a truncated form of the enzyme, lacking the N-terminal propeptide domain and the C-terminal hemopexin-like domain. The overexpressed protein was localized exclusively to insoluble inclusion bodies, in which it was present as both an intact form and an N-terminally truncated form. Inclusion bodies were solubilized in an 8 M guanidine-HCl buffer and purified by gel filtration chromatography under denaturing conditions. Partial refolding of the protein by dialysis into a 3 M urea buffer caused selective degradation of the truncated form of the protein, while the intact catalytic domain was unaffected by proteolysis. An SP-Sepharose chromatography step purified the protein to homogeneity and served also to complete the refolding. The purified protein was homogeneous by mass spectrometry and had an activity similar to that of the recombinant enzyme purified from mammalian cells. The protein was both soluble and monodisperse at a concentration of 9 mg/ml. This purification procedure enables the production of 23 mg of protein per liter of E. coli culture and is amenable to large-scale protein production for structural studies.