Nonthermal plasma air disinfection for the inactivation of airborne microorganisms in an experimental chamber and indoor air.

AIMS: Airborne transmission of diseases presents a serious threat to human health, so effective air disinfection technology to eliminate microorganisms in indoor air is very important. This study evaluated the effectiveness of a non-thermal plasma (NTP) air disinfector in both laboratory experiments and real environments. METHODS AND RESULTS: An experimental chamber was artificially polluted with a bioaerosol containing bacteria or viruses. Additionally, classroom environments with and without people present were used in field tests. Airborne microbial and particle concentrations were quantified. A 3.0 log10 reduction in the initial load was achieved when a virus-containing aerosol was disinfected for 60 min and a bacteria-containing aerosol was disinfected for 90 min. In the field test, when no people were present in the room, NTP disinfection decreased the airborne microbial and particle concentrations (P < 0.05). When people were present in the room, their constant activity continuously contaminated the indoor air, but all airborne indicators decreased (P < 0.05) except for planktonic bacteria (P = 0.094). CONCLUSIONS: NTP effectively inactivated microorganisms and particles in indoor air.

Establishment of a novel target-based real-time quantitative PCR method for Acinetobacter baumannii detection.

Biofilm formation is a well-known pathogenic mechanism in infections caused by Acinetobacter baumannii. Recently, a biofilm synthesis-associated gene has been found in A. baumannii ATCC19606. Bioinformatic analysis showed 2 transmembrane structures and an hmsS superfamily domain, which was related to biofilm formation. What is more, high homology sequences of the bfs gene were only present in A. baumannii spp., and the similarities of nucleotide sequences of the bfs gene from A. baumannii strains ATCC17978, ACICU, S1, AB307-0294, and AB0057 compared with the reported sequence of bfs (GenBank accession No.: NZ_GG704572) were all above 95%. The distribution and conservation of the bfs gene from clinically derived A. baumannii strains were verified through conventional polymerase chain reaction (PCR). After this, we established a bfs gene-based real-time quantitative PCR assay to detect A. baumannii. Species specificity and sensitivity assays were designed and validated. By using this method, all the A. baumannii strains separated from clinical samples were identified and showed good accordance with the results from biochemical identification. This study is the first report of developing a bfs gene-based quantitative polymerase chain reaction for rapid, stable, and specific detection of A. baumannii. This method can be applied to clinical laboratory diagnosis, and detection of A. baumannii present on medical instruments.