Human beta defensin 2 (HBD‐2), the most recently discovered human defensin, has been considered to work as a host defense substance against microbial infection. Using Escherichia coli ATCC 25922, we investigated how some cations and anions influenced the antimicrobial activity of HBD‐2. This activity, measured in 10 mm phosphate buffer at a concentration of 20 μg/ml, reduced significantly in the presence of 100 and 150 mm sodium or potassium chloride. The reduction was not significantly different when the total amounts of sodium and potassium ions were equal. The kind and the valence of anions (chlorine and sulfate ions) did not affect the bactericidal activity as long as the concentrations of sodium ions were equal. Divalent ions (calcium and magnesium ions) added to 10 mm of Tris buffer significantly inactivated HBD‐2 at much lower concentrations (more than or equal to 0.01 mm and 0.05 mm, respectively) than the monovalent ions did. These findings suggest that HBD‐2 kills the bacteria through at least two phases, which are affected independently by either monovalent or divalent ions and unaffected by anions.

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Defensins comprise a family of cationic antimicrobial peptides that is characterized by the conserved 6 cysteine residues. They are expressed in the epithelial cells of various organs and are identified as key elements in the host defense system at the mucosal surface. We isolated a novel mouse ␤-defensin gene from the bacterial artificial chromosome DNA containing the mouse ␤-defensin-3 gene. The full-length cDNA was cloned from skeletal muscle cDNA and called mouse ␤-defensin-6 (mBD-6). The predicted peptide conserved the 6-cysteine motif and had 59% amino acid sequence identity with mouse ␤-defensin-3 and 59% identity with mouse ␤-defensin-4. We demonstrated the expression of mBD-6 in skeletal muscle in addition to the esophagus, tongue, and trachea. In animal models of endotoxemia, mBD-6 expression was also induced in the lung. mBD-6 showed potent antimicrobial activity against Escherichia coli and would play an important role in host defense in the esophagus, airways, and skeletal muscle. mBD-6 is the first reported ␤-defensin predominantly expressed in skeletal muscle. This unique tissue specificity suggests some novel physiological roles of this peptide family.

Human cytomegalovirus (HCMV) open reading frame (ORF) UL11 locates within a polymorphic region of the viral genome identified previously by a restriction-fragment-length-polymorphism. We report here that ORF UL11 encodes a polymorphic protein expressed on the surface of HCMV-infected cells. First, we determined the nucleotide sequence of ORF UL11 from ten strains and compared it among the strains. Out of 205 amino acids consisting of the predicted N-terminal region beside the putative transmembrane stretch in strain AD169, 88 residues were divergent on more than one strain. In contrast, the predicted C-terminal side including the putative transmembrane domain was identical at the amino acid sequence level. In addition, the number and location of predicted cysteine residues were also conserved. Next, we screened a cDNA library from HCMV-infected cells and obtained a cDNA clone containing the full-length ORF UL11. Finally, we identified the gene product of UL11 on the surface of HCMV-infected cells by FACS analysis with polyclonal antibodies generated against a glutathione S-transferase/UL11 fusion protein. The fusion protein contained a region within the N-terminal side next to the predicted transmembrane stretch. These results indicate that the N-terminal side of UL11 protein containing variable amino acid residues protrudes from the infected cell surface.

The Verigene Gram-positive blood culture test (BC-GP) and the Verigene Gram-negative blood culture test (BC-GN) identify representative Gram-positive bacteria, Gram-negative bacteria and their antimicrobial resistance by detecting resistance genes within 3 h. Significant benefits are anticipated due to their rapidity and accuracy, however, their clinical utility is unproven in clinical studies. We performed a clinical trial between July 2014 and December 2014 for hospitalized bacteremia patients. During the intervention period (N = 88), Verigene BC-GP and BC-GN was used along with conventional microbiological diagnostic methods, while comparing the clinical data and outcomes with those during the control period (N = 147) (UMIN registration ID: UMIN000014399). The median duration between the initiation of blood culture incubation and the reporting time of the Verigene system results was 21.7 h (IQR 18.2-26.8) and the results were found in 88% of the cases by the next day after blood cultures were obtained without discordance. The hospital-onset infection rate was higher in the control period (24% vs. 44%, p = 0.002), however, no differences were seen in co-morbidities and severity between the control and intervention periods. During the intervention period, the time of appropriate antimicrobial agents' initiation was significantly earlier than that in the control period (p = 0.001) and most cases (90%; 79/88) were treated with antimicrobial agents with in-vitro susceptibility for causative bacteria the day after the blood culture was obtained. The costs for antimicrobial agents were lower in the intervention period (3618 yen vs. 8505 yen, p = 0.001). The 30-day mortality was lower in the intervention period (3% vs. 13%, p = 0.019).