ABSTRACT
Five laboratory-acquired brucellosis (LAB) cases that occurred in the United States between 2008 and 2011 are presented. The Centers for Disease Control and Prevention (CDC) reviewed the recommendations published in 2008 and the published literature to identify strategies to further prevent LAB. The improved prevention strategies are described.
Subject(s)
Brucellosis/diagnosis , Brucellosis/prevention & control , Infection Control/methods , Occupational Exposure , Adult , Child , Female , Health Personnel , Humans , Male , Middle Aged , United StatesABSTRACT
Seven diazotrophs that grow well under Mo-deficient, N(2)-fixing conditions were isolated from a variety of environments. These isolates fall in the gamma subdivision of the class Proteobacteria and have genes that encode the Mo nitrogenase (nitrogenase 1) and the V nitrogenase (nitrogenase 2). Four of the isolates also harbor genes that encode the iron-only nitrogenase (nitrogenase 3).
Subject(s)
Environmental Microbiology , Gammaproteobacteria/isolation & purification , Genes, Bacterial , Nitrogen Fixation/genetics , Nitrogenase/genetics , Amino Acid Sequence , Gammaproteobacteria/genetics , Gammaproteobacteria/growth & development , Gammaproteobacteria/metabolism , Iron/chemistry , Molecular Sequence Data , Molybdenum/chemistry , Nitrogenase/chemistry , Nitrogenase/metabolism , Phylogeny , RNA, Ribosomal, 16S/genetics , Water MicrobiologyABSTRACT
Oxygen free radicals present a serious potential threat to microbial survival, through their ability to inflict indiscriminate damage on proteins and DNA. Superoxide dismutase (SOD, EC 1.15.1.1), among other oxygen-metabolizing enzymes, is essential to prevent these toxic molecules from accumulating in the bacterial cytosol during aerobic metabolism. The gene sodA, encoding manganese-containing SOD ([Mn]-SOD), has been cloned from a virulent strain of Haemophilus influenzae type b using degenerate oligonucleotides encoding regions of the gene conserved across different bacterial species. The gene product has been identified as [MN]-SOD by its similarity at key amino acid residues to known examples of the enzyme, by expression of enzymatically active protein from cloned DNA expressed in Escherichia coli, and by demonstration that an in-frame deletion in the gene abolishes this activity. In contrast to the situation in E. coli, this [Mn]-SOD is the only active SOD detected in H. influenzae. In further contrast to E. coli, [Mn]-SOD gene expression in H. influenzae has been found to be only partially repressed under anaerobic conditions. When expressed in E. coli the gene is regulated by Fur and Fnr, and the promoter region, identified experimentally, has been found to contain nucleotide sequence motifs similar to the Fur- and Fnr-binding sequences of E. coli, suggesting the involvement of analogues of these aerobiosis-responsive activators in H. influenzae gene expression.
