Investigation of the disinfection efficiency of commercial hydrogen peroxide, chlorine dioxide, and chlorine disinfectant on different surfaces.

OBJECTIVE: The disinfection efficiency of disinfectants differs in specific conditions. This study aimed to investigate the disinfection efficiency of commercial hydrogen peroxide, chlorine dioxide, and chlorine disinfectant on real field surfaces and provide data for precise disinfection. METHODS: Simulated field disinfection and field disinfection methods were conducted to quantitatively evaluate the disinfection efficiency of hydrogen peroxide, chlorine dioxide, and sodium dichloroisocyanurate. The log10 reduction of biological indicators, Escherichia coli (ATCC 8099) and Staphylococcus aureus (ATCC 6538), was calculated. Next, the reduction in natural bacteria on the surfaces of a food production and processing workshop and a biosafety laboratory was determined. RESULTS: The 3 commercial disinfectants evaluated were effective against E coli and S aureus, with a reduction of more than 3.00 log10 colony-forming units/mL tested for an exposure time of 15 minutes with 3.5% hydrogen peroxide, 100 mg/L chlorine dioxide, and 250 mg/L sodium dichloroisocyanurate. The natural load in the food production and processing workshop decreased by more than 90% using 10.5% hydrogen peroxide with an exposure time of 30 minutes. The same disinfection level in the biosafety level 2 laboratory was achieved by 500 mg/L chlorine dioxide at an exposure time of 60 minutes and 450 mg/L sodium dichloroisocyanurate at 60 minutes. CLINICAL RELEVANCE: This study provides a reference for precise disinfection of surfaces in the food industry and biosafety laboratories.

Enzymatic reporting of peste des petits ruminants virus genes ligating two specific probes on nanoparticles.

An alternative strategy for the detection of nucleic acid derived from peste des petits ruminants virus was developed omitting amplification. The assay is based on two probes complementary to the target sequences, one conjugated to magnetic microparticles the second to gold nanoparticles labeled with horseradish peroxidase. In the presence of target gene the two particles ligate via the probes and the complex can be magnetically separated. Applying substrate and chromogen a color reaction results for a positive case. Under optimized conditions, the approach had a linear detection range from 10 fM to 1 µM for ssDNA corresponding to an RNA low detection limit of 17.6 ng/µl. The quick performance (45 min) and not requiring expensive instrumentations offer a new way of detecting nucleic acids for the clinical diagnosis in our case for peste des petits ruminants virus.

Bactericidal efficacy of mobile ultraviolet-C disinfection devices in reducing contamination in biosafety laboratories.

INTRODUCTION: Biosafety research requires a wide range of microorganisms and thorough disinfection to prevent laboratory infection is often required. Ultraviolet-C (UV-C) exposure reduces bacterial and viral concentrations. Therefore, in this study, we aimed to evaluate the efficacy of a mobile UV-C device as a non-contact disinfection strategy. METHODOLOGY: The bactericidal efficacy of the UV-C device was determined based on log10 decreases in the relative abundances of bacterial indicators, including Escherichia coli, Staphylococcus aureus, Staphylococcus albus, and Pseudomonas aeruginosa at 0.5 and 1.0 m after irradiation for 30, 60, and 90 min. Next, the reduction of natural bacteria in air and on surface as a result of the UV-C device exposure in the laboratory were determined. RESULTS: Exposure to the UV-C disinfection device resulted in mean log10 decreases in microbial contamination of 3.55 and 5.85 following irradiation for 30 and 90 min, respectively, at a distance of 0.5 m. Further, P. aeruginosa and E. coli were the most and least sensitive to UV-C exposure, respectively. The bacterial load in air decreased by 65.53% after 60 min of irradiation, while those on surfaces decreased by 44.19% and 78.23% after 30 and 60 min of irradiation, respectively. CONCLUSIONS: The UV-C device effectively reduced bacterial load after irradiation for over 60 min. Further studies are encouraged to determine the effectiveness of the UV-C disinfection device in frequently occupied institutions, such as primary medical, health, and nursery, and its efficiency in infection control.

Complete genome sequence of a highly pathogenic porcine reproductive and respiratory syndrome virus variant isolated from a backyard piglet.

The highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) isolates have showed accelerating evolution under the great immune pressure in China in recent years. Here, we report the complete genome sequence of the HP-PRRSV variant GX1001 isolated from a vaccinated backyard piglet.

Complete genome sequence of a porcine reproductive and respiratory syndrome virus variant with a new deletion in the 5' untranslated region.

The GX1002 strain is a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) characterized by a continuous 2-nucleotide deletion at positions 119 and 120 in the 5' untranslated region. This differs from prevalent HP-PRRSVs in China, which have a deletion of only 1 nucleotide at position 119. Here we report the complete genome sequence of the GX1002 strain.

Recombinant adenovirus expressing F and H fusion proteins of peste des petits ruminants virus induces both humoral and cell-mediated immune responses in goats.

Peste des petits ruminants (PPR) is an acute and contagious disease of some small ruminants caused by peste des petits ruminants virus (PPRV). Fusion (F) protein and hemagglutinin (H) protein are two glycoproteins of PPRV that might induce a protective immune response. In this study, three replication-defective recombinant adenoviruses were constructed and the immunogenicity was evaluated in goats (the natural host). The recombinant adenoviruses (rAds) expressing F, H, and F-H fusion protein were named rAd-F, rAd-H, and rAd-F-H, respectively. In vitro, the proteins expressed in AAV-293 cells infected with different rAds were identified by Western blotting and immunofluorescence. The results showed that the proteins could be expressed in vitro. Three groups of goats (6 goats per group) were inoculated subcutaneously twice at 3-week intervals with the rAds. As negative controls, two additional groups were inoculated with wild-type adenovirus (wtAd) or PBS. In vivo, goats immunized with the rAds developed PPRV-specific virus neutralizing antibody (VNA) by 3 weeks after primary immunization. Moreover, the seroconversions were maintained for approximately 21 weeks after primary immunization. Stronger lymphocyte proliferation responses were induced in goats immunized with the three rAds than in the negative controls (P<0.05). Notably, goats inoculated with rAd-F-H developed significantly higher VNA titers (P<0.05) and stronger cell-mediated immune responses than did goats inoculated with rAd-F or rAd-H alone. The results suggest that the three rAds might be attractive candidate differentiating infected from vaccinated animals (DIVA) vaccines for preventing PPRV infection. Notably, the rAd-F-H expressing F-H fusion protein is likely the most potent candidate of the rAds.