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Background Human-use probiotics have recently been associated with clinical infections and antibiotic resistance transfer, raising public concern over their safety. However, despite their extensive application in aquaculture and animal husbandry, the safety of animal-use probiotics remains poorly described. Methods We evaluated the safety of 92 animal-use probiotics from China. The pattern of spread of pathogens from probiotics and the consequent public health implications were also examined by conducting in-field genomic surveillance at 2 farms. Results A total of 123 probiotic Bacillus species isolates were obtained from 92 brands of probiotics, of which 45 isolates were resistant to antibiotics. Notably, 33.7% of probiotic products were contaminated with life-threatening pathogens such as Klebsiella pneumoniae. Genomic surveillance at a chicken farm identified an anthrax toxin–positive Bacillus cereus strain in a probiotic product used as a feed supplement, which was transferred into the groundwater and to a nearby fish farm. Following up retrospective analysis of the surveillance data during 2015–2018 in 3 provinces retrieved 2 B. cereus strains from human with intestinal anthrax symptoms and confirmed the transmission of B. cereus from farm to human. Surveillance of anthrax toxin revealed that cya was detected in 8 of 31 farms. Conclusions This study provides the first national safety survey of animal-use probiotics in China and confirms the spillover effects of probiotics from the farms to human. These results suggest that the large-scale application of pathogen-containing probiotics leads to the transfer of pathogens, with worrisome implications for public health. Good Manufacturing Practice should be implemented during the production of all probiotics. Animal-use probiotic products are frequently contaminated with viable pathogenic bacteria. This study revealed that virulent probiotic organisms and contaminating pathogens were colonized with farm animals and shed into the environment, which facilitated the transfer of pathogens to humans. [ABSTRACT FROM AUTHOR]

A semiconductor manufacturing system that involves a large number of items and many steps can be modelled through conservation laws for a continuous density variable on a production process. In this paper, the basic hyperbolic partial differential equation (PDE) models for multiple re-entrant manufacturing systems are proposed. However, through numerical examples, the basic continuum models do not perform well for small-scale multiple re-entrant systems, so a new state equation taking into account the re-entrant degree of the product is introduced to improve the basic continuum models. The applicability of the modified continuum model is illustrated through a numerical example. Based on the modified continuous model, this paper studies the optimal control problems for multiple re-entrant manufacturing systems. The gradient of the cost function with respect to the influx is solved by the adjoint approach, and then the optimal influx is computed by the steepest descent method. Finally, numerical examples on optimal influx profiles for steps in demand rate, linear demand rate and periodically varying demand rate are given. The relationships among influx, outflux and demand are also discussed in detail. [ABSTRACT FROM AUTHOR]

This article aims to understand the changes in the detection rates of H5, H7, and H9 subtypes of avian influenza viruses (AIVs) in the live poultry markets (LPMs) in Nanchang City, Jiangxi Province, before and after the outbreak of the COVID-19. From 2019 to 2020, we monitored the LPM and collected specimens, using real-time reverse transcription polymerase chain reaction technology to detect the nucleic acid of type A AIV in the samples. The H5, H7, and H9 subtypes of influenza viruses were further classified for positive results. We analyzed 1,959 samples before and after the outbreak and found that the positive rates of avian influenza A virus (39.69%) and H9 subtype (30.66%) after the outbreak were significantly higher than before the outbreak (26.84% and 20.90%, respectively; P < 0.001). In various LPMs, the positive rate of H9 subtypes has increased significantly (P ≤ 0.001). Positive rates of the H9 subtype in duck, fecal, daub, and sewage samples, but not chicken samples, have increased to varying degrees. This study shows that additional measures are needed to strengthen the control of AIVs now that LPMs have reopened after the relaxing of COVID-19-related restrictions.