Abstract: Aquaculture is part of the crucial industry that supplies food, especially for the global human population that is gradually increasing annually. Innovations of culture techniques have been improved throughout the years but aquaculture is regularly susceptible to bacterial and viral diseases. Numerous factors could contribute to occurrence of disease and usually they are from environmental or human stressors on the cultured animals. Synthetic chemicals in commercial treatments may yield fast results however, the side effects are usually unknown until it has taken effect. Therefore, biological control methods to treat diseases in aquaculture are preferred. This mini review provides an overview of different potential biocontrol practices for treatment of bacterial and viral diseases. Bacteriophage causes death of pathogenic bacteria by killing the cell and continue to multiply until all targeted pathogenic bacteria are eliminated. Probiotic, prebiotic, synbiotic, biofloc, and immunostimulants are beneficial products from the respective organisms that are effective in inhibiting pathogens. Vaccines introduce inactivated pathogen into the body to stimulate the immune system, while genetic modifications involve alteration and selection of disease resistant genetics.

Abstract: An air washer-type humidifier has two useful functions: humidification, and air purification, and it applies to large indoor spaces. In this study, the efficacy of an air washer-type humidifier fed with 24 L of weakly acidic electrolyzed water（WAEW) at pH 5.0 and 30 mg/L in disinfecting attached bacteria and airborne microorganisms was studied in a 480 ^m3 indoor space. The humidifier was operated at a shower volume of 9.0 L/min of WAEW and at an air flow rate of 29 ^m3/min. Volatilization of gaseous hypochlorous acid（HOCl_(g)) proceeded according to first-order kinetics during the 60 min of operation. Fresh WAEW was supplied to the humidifier every 60 min, and the HOCl_(g) concentration in the indoor space was maintained within the range of 25–52 ppb for at least 180 min of operation. The number of viable bacterial cells on wet agar plates placed on the floor at a distance of 5–20 m away from the humidifier decreased by 2.0–3.0 log after 30 min of operation, and no viable cells were detected after 60 min of operation. A logarithmic reduction of more than 2.7 was achieved within 15 min against bacteria-attached plates placed at a 1.5 m-height position where the outlet airflow from the humidifier was directly exposed. This indicates that the disinfection efficacy of HOCl_(g) volatilized from the humidifier depends on the rate of outlet airflow reaching the bacteria-attached plates. The number of viable airborne microorganisms decreased by approximately 54% after 180 min of operation. This study demonstrated that an air-washer-type humidifier can spread HOCl_(g) evenly throughout a large indoor space and is effective in disinfecting attached bacteria and airborne microorganisms.

Abstract: This study searched for volatile organic compounds (VOCs）having antibacterial and antiviral efficacy. The antibacterial efficacy of volatilized components was evaluated and (2E,4E）-2,4-hexadienal, α- angelica lactone, 2-cyclohexen-1-one and 2-cyclopenten-1-one were found to inhibit the formation of colonies of Staphylococcus aureus and Escherichia coli. Evaluating the antimicrobial efficacy of the surfaces to which each VOC adhered to, these four compounds were revealed to have antibacterial efficacy (antibacterial activity value (A-value）against S. aureus; ≧2.63, A-value against Klebsiella pneumoniae; >5.07, A-value against E. coli; ≧2.17）. Furthermore, (2E,4E）-2,4-hexadienal and α-angelica lactone were found to have antiviral efficacy against Influenza A virus (H1N1）and Feline calicivirus on the cotton cloths to which it adheres to (antiviral activity value (R-value）against Influenza A virus; >2.94, R-value against Feline calicivirus; ≧2.31）. Using these components, it might be possible to develop antimicrobial products that exhibit antibacterial and antiviral efficacy.

Abstract: Plasmid-mediated antibiotic-resistant bacteria’s transmission is fatal and a major threat to public health. This study aimed to clarify the presence of plasmid-mediated quinolone resistance（PMQR）genes in extended-spectrum β-lactamase（ESBL）-producing or/and mcr-harbouring colistin（COL）-resistant Escherichia coli（ESBL-COL-EC）isolates from Vietnamese and Japanese chicken meat. Resistance towards ciprofloxacin（CIP）was examined in 308 ESBL-COL-EC isolates; CIP-resistant ESBL-COL-EC isolates were examined for the PMQR gene. Approximately, 71.1% and 38.1% of ESBL-COL-EC and ESBLproducing E. coli isolates from Vietnamese and Japanese chicken meat were CIP-resistant, respectively. Multiplex PCR led PMQR detection showed that 35.2% of CIP-resistant ESBL-COL-EC isolates from Vietnamese food contained PMQR gene, whereas CIP-resistant ESBL-COL-EC isolates from Japanese chicken meat did not. Conjugation assays showed that the transmission of qnrS gene carried by E. coli to Salmonella. In conclusion, ESBL-COL-EC isolates from Vietnamese food are associated with a high frequency of fluoroquinolone resistance and a high distribution of the qnrS gene.