Pilot randomized experimental study evaluating isopropyl alcohol and ultraviolet-C radiation in the disinfection of healthcare workers' smartphones.

BACKGROUND: Smartphones in medical settings pose infection risks due to harbouring pathogenic bacteria. AIM: This pilot study assessed the effectiveness duration of sanitization methods, focusing on 70% isopropyl alcohol wipes and ultraviolet-C (UVC) boxes, aiming to obtain preliminary data on the reduction in total bacterial load 3 h post-sanitization. METHODS: A randomized monocentric trial with two intervention arms (wipes and UVC boxes) was designed. As participants, healthcare workers from three wards at Fondazione Policlinico Universitario 'A. Gemelli' IRCCS Hospital were recruited, stratified by ward, and block randomized within each ward to control confounders. FINDINGS: Seventy-one healthcare workers, mostly nurses (62%) were included in the study. Initial bacterial load reduction was significant with both disinfection techniques, but after 3 h both methods showed increased bacterial levels, with wipes displaying potentially higher residual efficacy (P=0.056). To adequately size a trial (89% power, significance level 0.05) for assessing the residual efficacy of alcohol-impregnated wipes compared with UVC boxes at 3 h post-sanitization, 503 professionals per group were required. CONCLUSION: This study highlights the necessity for guidelines on hospital smartphone sanitization and educational initiatives for healthcare workers and patients. Further studies, adequately sized, are necessary to determine optimal sanitization intervals and assess pathogen transmission risks.

Biochemical characterization of a hepatitis C virus RNA-dependent RNA polymerase mutant lacking the C-terminal hydrophobic sequence.

The RNA-dependent RNA polymerase activity of hepatitis C virus is carried out by the NS5B protein. The full-length protein was previously purified as a non-fusion protein from insect cells infected with a recombinant baculovirus. The characterization is now described of a C-terminal hydrophobic domain deletion mutant of NS5B purified from E. coli. In addition to increased solubility, deletion of this sequence also positively affected the polymerase enzymatic activity. The efficiency of nucleotide polymerization of both the full-length and the C-terminal truncated enzymes were compared on homopolymeric template-primer couples as well as on RNA templates with heteropolymeric sequences. The largest difference in the polymerase activity was observed on the latter. On all the templates, the increased activity could be ascribed, at least in part, to enhanced template turnover of the deletion mutant with respect to the full-length enzyme. The elongation rates of the two enzyme forms were compared under single processive cycle conditions. Under these conditions, both the full-length and the deletion mutant were able to incorporate about 700 nt/min.

Crystal structure of the RNA-dependent RNA polymerase of hepatitis C virus.

We report the crystal structure of the RNA-dependent RNA polymerase of hepatitis C virus, a major human pathogen, to 2.8-A resolution. This enzyme is a key target for developing specific antiviral therapy. The structure of the catalytic domain contains 531 residues folded in the characteristic fingers, palm, and thumb subdomains. The fingers subdomain contains a region, the "fingertips," that shares the same fold with reverse transcriptases. Superposition to the available structures of the latter shows that residues from the palm and fingertips are structurally equivalent. In addition, it shows that the hepatitis C virus polymerase was crystallized in a closed fingers conformation, similar to HIV-1 reverse transcriptase in ternary complex with DNA and dTTP [Huang H., Chopra, R., Verdine, G. L. & Harrison, S. C. (1998) Science 282, 1669-1675]. This superposition reveals the majority of the amino acid residues of the hepatitis C virus enzyme that are likely to be implicated in binding to the replicating RNA molecule and to the incoming NTP. It also suggests a rearrangement of the thumb domain as well as a possible concerted movement of thumb and fingertips during translocation of the RNA template-primer in successive polymerization rounds.