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A strain of Bacillus subtilis (B. subtilis) BYS2 was previously isolated from Mount Tai, which is located in Tai’an City in the Shandong Province of China. The strain was then stored in the Environmental Microbiology Laboratory at Shandong Agricultural University. To evaluate the effect of the bacterium preparation in broiler production, we fed the bacterium (106 CFU/g) to 1-day-old broilers and continued this feeding for 6 weeks to analyze its effect on growth and immune performance. We found that the average weight of the bacterium-fed group increased by 17.19% at weeks 5 compared to the control group (P

Bacillus subtilis BYS2 is a strain with a broad inhibitory spectrum against pathogenic bacteria. In the current study, we report the complete genome sequence of Bacillus subtilis BYS2. The chromosome of BYS2 (4,030,791 bp; G+C content, 43.88%) contained 3,914 protein-encoding genes, with 86 tRNAs, 30 rRNAs, and 5 noncoding RNAs (ncRNAs).

Different samples were collected from three swine farms in China to investigate the spread of antibiotic-resistant Escherichia coli. A total of 130 E. coli isolates were obtained from feces, air, river water, silt, and soil samples and characterized. The susceptibility of the E. coli isolates to 19 antibiotics was tested. The results revealed that the resistance rates of the E. coli isolates against 9 antibiotics were high. The minimum inhibitory concentration (MIC) values of ciprofloxacin, ofloxacin, and nalidixic acid were mainly in the ranges of 2–64, 8–64, and 8–64 μg/ml. The plasmid-mediated quinolone resistance (PMQR) genes qnr, aac(6′)-Ib-cr, qepA, and oqxAB were detected by polymerase chain reaction (PCR), and the similarity of E. coli from different samples was identified by pulsed-field gel electrophoresis (PFGE). The detection rates of the qnrA, qnrB, qnrS, aac(6′)-Ib-cr, qepA, and oqxAB genes in the E. coli isolates from three swine farms were in the range of 10.87–23.08%, 13.04–20.51%, 40.00–43.48%, 30.43–38.46%, 6.52–12.82%, and 7.69–17.39%, respectively. The PFGE result showed that 49% (49/100) of isolates originating from air, river water, soil, and silt samples had ≥85% similarity to fecal-obtained isolates, and 40.82% (20/49) of them shared the same PMQR genes with fecal-obtained isolates. This indicated that E. coli carrying PMQR genes and originating from feces in swine farms could spread to the external environment, which could be a potential threat to the public environment and human health.

Escherichia coli is a common bacterium in the air; it can affect the health of humans and animals. The carrying status of five primary virulence factor genes in E. coli (i.e., STa, STb, LTa, stx1, and stx2/stx2e) in various animal houses and their spread to the outside environment were investigated by comparing the air inside animal houses with that outside the houses. Multiplex polymerase chain reaction detection of the five genes was performed on samples from five chicken houses, and 117 E. coli isolates were obtained. From five swine houses, 120 were obtained, and from six cow houses, 143 were obtained. Results reveal that E. coli virulence genes derived from animal houses can be propagated via gas exchange from the inside to the outside and, depending on weather conditions, across some distance, resulting in biological pollution and the spread of pathogenic microorganisms. This study of the transmission of environmental microbial aerosols in animal houses has great significance in public health and epidemiology.

Bacteria and fungi are primary constituents of airborne microbes in fine particulate matter and harmful to health. To evaluate the environmental quality of different poultry houses in Shandong Province, China, the airborne aerobic bacteria, airborne fungi, and airborne Escherichia coli were collected by the Andersen-6 air microorganism sampler. The fine particulate matter was collected by a ZR-3920 ambient air particulate matter sampler, and bacterial and fungal diversities and relative abundances analyzed using high-throughput sequencing. Results showed that the concentrations of airborne aerobic bacteria, airborne fungi, and airborne Escherichia coli in poultry houses were 0.167 to 4.484 × 104 CFU/m3, 0.236 to 4.735 × 103 CFU/m3, and 0 to 33.0 CFU/m3, respectively. 11.4 to 34.3% of aerobic bacteria and 16.8 to 37.5% of fungi were distributed at levels 5 and 6 (0.6 to 2.1 μm, the particle sizes similar to fine particulate matter) in the Andersen sampler. The concentration of fine particulate matter in the poultry houses was 114 to 230 μg/m3, which was higher than the safety value 10 specified by WHO. In fine particulate matter, the main bacteria at phylum level were Firmicutes, Bacteroidetes, and Proteobacteria, whereas the dominant phylum of fungus was Ascomycota and Basidiomycota. Importantly, the relative abundances of Escherichia and Corynebacterium in the broiler houses were greater than those in layer houses. However, the percentages of Aspergillus and Penicillium were 13.5 and 0.56%, with a relatively high level in the layer houses. Altogether, results revealed that the ambient air quality in the poultry houses sampled had a relatively high abundance of conditional pathogenic bacteria and concentration of fine particulate matter, which could threaten the health of animals and workers in those environments.

// Mengjiao Guo 1,2 , Wenhao Yang 1 , Fahao Wu 1 , Guangen Hao 1 , Rong Li 1 , Xinyu Wang 1 , Liangmeng Wei 1,2 and Tongjie Chai 1 1 College of Animal Science and Veterinary Medicine, Sino-German Cooperative Research Centre for Zoonosis of Animal Origin of Shandong Province, Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Tai’an, Shandong, China 2 Collaborative Innovation Center for the Origin and Control of Emerging Infectious Diseases, Taishan Medical University, Taian City, China Correspondence to: Liangmeng Wei, email: // Tongjie Chai, email: // Keywords : enterohemorrhagic Escherichia coli, pathogenicity, innate immunity, cytokines, rabbits, Immunology and Microbiology Section, Immune response, Immunity Received : July 26, 2017 Accepted : September 03, 2017 Published : September 16, 2017 Abstract The major virulence factor of enterohemorrhagic Escherichia coli in infections is its ability to cause attaching and effacinglesions in enterocytes, as well as to produce Shiga toxins. To clarify the pathogenic mechanism and host innate immune responses of enterohemorrhagic Escherichia coli in rabbits, experimental infections with TS and MY strains were conducted. Among the results, although the MY strain’s pathogenicity was stronger than the TS, typical symptoms were observed in both groups of bacterial-infected rabbits. Pathological changes in the heart, liver, and spleen of rabbits infected with the MY strain were more severe than those infected with theTS strain, pro-inflammatory cytokines IL-1β, IL-6, IL-8, IFN-γ, and TNF-α were induced by both strains, and α- and β-defensin were significantly upregulated at 3 d postinfection. Moreover, in the spleen, the MY strain induced greater expressions of α- and β-defensins than did the TS strain. However, in the liver, the TS strain induced greater expressions of α- and β-defensins than did the MY strain. Most likely, different replications of the MY and TS strains in the liver and spleen induced different host immune responses. Altogether, the findings provide new insights into the occurrence and development of enterohemorrhagic Escherichia coli -mediated diseases in rabbits.

Aspergillus fumigatus is a ubiquitous pathogen in poultry farms, causing aspergillosis in chickens. To study the pathogenicity of A. fumigatus, 14-days-old chickens were infected with fungal conidia (2 × 107 CFU/mL) via thoracic intra-air sacs inoculation. The clinical symptoms, gross and histopathological lesions, and fungal load in the lungs were examined. Additionally, the mRNAs of Toll like receptors (TLR) and pro-inflammatory cytokines were evaluated by quantitative PCR to explore the immune responses induced by A. fumigatus. The results showed that overt depression, ruffled feathers, and dyspnea were observed in the infected chickens as early as 3 days post infection (dpi). Eleven out of 25 infected chickens died from 5 to 9 dpi, and A. fumigatus could also be reisolated from the infected lung. Histopathological examination revealed obvious airsacculitis and pneumonia, characterized by inflammatory cell infiltration (heterophils and macrophages), and granulomatous lesions in the lung. The mRNA expressions of TLR1 and TLR2 were upregulated in the lung and spleen, and most pro-inflammatory cytokines including IL-1β, Cxcl-8, TNF-α, IL-12, and IFN-γ were increased in both the lung and spleen during the tested period, suggesting that the innate immune responses were triggered by A. fumigatus infection, and these cytokines participated in the inflammatory responses against A. fumigatus. These results indicate that A. fumigatus infection by thoracic intra-air sacs inoculation can cause severe respiratory damage in chickens, activate TLR1 and TLR2 mediated immune responses, and elicit large expression of pro-inflammatory cytokines such as IL-1β, Cxcl-8, and IFN-γ. These data will help further understanding of the pathogenesis and immune responses of A. fumigatus infection in the chicken.

Poultry-emitted air pollutants, including microbial aerosols and particulate matter, have raised concerns due to their potential negative effects on human health and the environment. High concentrations of microbial aerosols can also significantly affect duck production performance, leading to immunosuppression and increased disease susceptibility. We determined the concentrations, distributions, and biological components of the microbial aerosols and particulate matter in a duck house environment. The concentration ranges of the bacteria, fungi, Gram-negative bacteria, Escherichia coli, and endotoxin in the duck houses were 3.3 to 5.2 × 104 CFU/m3, 3.8 to 11.9 × 103 CFU/m3, 2.1 to 3.6 × 103 CFU/m3, 1.3 to 2.7 × 102 CFU/m3, and 0.65 to 2.2 × 103 EU/m3, respectively. We also found the endotoxin levels were higher than the standard that can cause pneumonia (2,000 EU/m3). The concentration ranges of the PM2.5 and PM10 samples were 1.1 to 1.6 × 102μg/m3 and 1.2 to 1.9 × 102μg/m3, respectively. At the phylum level, the top 5 bacteria identified in the PM2.5 fraction were Actinobacteria, Firmicutes, Proteobacteria, Bacteroidetes, and Fusobacteria, with Actinobacteria (50.55%) as the most abundant. At the genus level, 293 bacterial groups were identified. Actinobacteria (39.01%) was the most abundant phylum, followed by Firmicutes (5.44%) and Proteobacteria (4.56%). The bacterial distributions that differed between the PM2.5 and PM10 samples were Lactobacillales, Bacilli, Firmicutes, and Bacteroidetes; the fungi that differed were Microbotryomycetes, Sporidiobolales, Agaricomycetes, and Polyporates. Microbial allergens and pathogens were also identified. Corynebacterium had a relative abundance of more than 30% in the PM2.5 and PM10 distributions. Aspergillus was the main fungal allergen and opportunistic pathogen, with a relative abundance of 10%. In conclusion, our research supports that the microbial composition in the duck house environment poses a potential threat to the health of both the ducks and the duck house workers.

The polymerase acidic (PA) protein is the third subunit of the influenza A virus polymerase. In recent years, studies have shown that PA plays an important role in overcoming the host species barrier and host adaptation of the avian influenza virus (AIV). The objective of this study was to elucidate the role of the PA subunit on the replication and airborne transmission of the H9N2 subtype AIV. By reverse genetics, a reassortant rSD01-PA was derived from the H9N2 subtype AIV A/Chicken/Shandong/01/2008 (SD01) by introducing the PA gene from the pandemic influenza A H1N1 virus A/swine/Shandong/07/2011 (SD07). Specific pathogen-free (SPF) chickens and guinea pigs were selected as the animal models for replication and aerosol transmission studies. Results show that rSD01-PA lost the ability of airborne transmission among SPF chickens because of the single substitution of the PA gene. However, rSD01-PA could infect guinea pigs through direct contact, while the parental strain SD01 could not, even though the infection of rSD01-PA could not be achieved through aerosol. In summary, our results indicate that the protein encoded by the PA gene plays a key role in replication and airborne transmission of the H9N2 subtype AIV.

Antibiotic-resistant bacteria (ARB) present a global public health problem. Microorganisms are the main cause of hospital-acquired infections, and the biological contamination of hospital environments can cause the outbreak of a series of infectious diseases. Therefore, it is very important to understand the spread of antibiotic-resistant bacteria in hospital environments. This study examines the concentrations of aerobic bacteria and E. coli in ward environments and the airborne transmission of bacterial drug resistance. The results show that the three wards examined have an average aerobic bacterial concentration of 132 CFU∙m−3 and an average inhalable aerobic bacterial concentration of 73 CFU∙m−3, with no significant difference (P > 0.05) among the three wards. All isolated E. coli showed multi-drug resistance to not only third-generation cephalosporin antibiotics, but also quinolones, aminoglycosides, and sulfonamides. Furthermore, 51 airborne E. coli strains isolated from the air in the three wards and the corridor were screened for ESBLs, and 12 (23.53%) were ESBL-positive. The drug-resistance gene of the 12 ESBL-positive strains was mainly TEM gene, and the detection rate was 66.67% (8/12). According to a homology analysis with PFGE, 100% homologous E. coli from the ward at 5 m and 10 m outside the ward in the corridor shared the same drug-resistance spectrum, which further proves that airborne E. coli carrying a drug-resistance gene spreads out of the ward through gas exchange. This leads to biological pollution inside, outside, and around the ward, which poses a direct threat to the health of patients, healthcare workers, and surrounding residents. It is also the main reason for the antibiotic resistance in the hospital environment. More attention should be paid to comprehensive hygiene management in the surrounding environment of hospitals. Keywords: Microbial aerosol, Escherichia coli, PFGE, Drug-resistant genes, Public health, Environmental biological pollution

Particulate matter (PM) pollution poses a huge public health threat, and exposure to haze pollution for short or long periods of time cause health problems. In this study, 16S rDNA and ITS high-throughput sequencing were used to analyze the microbial components of fine particulate matter (PM2.5) collected between December 20th and December 27th of 2016 during a severe haze in Tai'an, China. Although most inhalable microorganisms are not pathogenic to humans, we detected the presence of some types of bacteria that cause respiratory inflammation (such as Pseudomonas and Corynebacterium), allergic reactions (such as Alternaria), and lung inflammation (such as Nesterenkonia). Acute and chronic haze PM2.5 exposure experiments were conducted using BALB/c mice to gain insight about the harm these microbes may have on human health. Results indicate that acute exposure to haze PM2.5 can cause pathological lung damage, decrease the expressions of oxidative stress indicators T-AOC, SOD, and GSH-PX, increase the expression of MDA, and induce apoptosis. Furthermore, chronic exposure was found to cause more damage. Toll-like receptors can be used identify molecular patterns associated with microbial pathogens. The expression of TLR2 and TLR4 were increased in both single- and repeated-exposure groups, but they were significantly increased in the repeated-exposure group (P

Galectin-1, as a typical animal galactose-binding protein, it is found on the cell surface and in the extracellular matrix. Cloning the full-length coding sequence of galectin-1 from the spleens of Cherry Valley ducks revealed that the coding sequence of duck galectin-1 (duGal-1) comprises 405 bp, encoding 134 amino acids. Homologic analysis revealed its amino acid sequence is most identical to that of Anas platyrhynchos (98.8%) followed by Gallus gallus. Quantitative real-time PCR analysis indicated that duGal-1 mRNA is broadly expressed in healthy Cherry Valley duck tissues, primarily in the heart and trachea but minimally in the lung and skin. Meanwhile, the duGal-1 expression is slightly upregulated in the infected liver and spleen. Furthermore, the expression levels of ISGs (Mx, PKR, OAS) and some cytokines such as IFN-α, IL-1β, IL-2, are up-regulated to varying degrees after overexpression the duGal-1, In contrast, Knockdown of duGal-1 found that the expression levels of ISGs and some inflammatory cytokines were down-regulated. Antiviral assay showed that duGal-1 could inhibit viral replications early during infection. This is the first study of the cloning, tissue distribution, and antiviral immune responses of duGal-1, and findings imply it is involved in the early stages of antiviral innate immune responses to duck plague virus infections in ducks.

The dissemination of extended spectrum beta-lactamases (ESBL) genes through gene transfer attracts wide attention. Bentonite is widely used as a feed additive in an animal-breeding environment. In order to obtain a better understanding of the effect of bentonite on Escherichia coli carrying ESBL gene, proteomic analysis was carried out to screen the key proteins. The results showed that a total of 31 proteins were differentially expressed, including 21 up-regulated proteins and 10 down-regulated proteins. These proteins were involved in biosynthetic process, metabolic process, stress response, transport, anaerobic respiration, proteolysis, hydrolase, protein folding, transcription, salvage, and other. The transcriptional level of four genes (mipA, gntY, tldD, and arcA) was in consensus with proteomic results. This study revealed the differentially expressed proteins involved when E. coli was incubated under bentonite and PBS condition, which implied the possibility that bentonite may promote the transfer of ESBL gene between E. coli.

The aim of this study was to detect severe fever with thrombocytopenia syndrome virus (SFTSV) infection using polymerase chain reaction (PCR) amplification in adult Haemaphysalis concinna ticks. A total of 72 adult H. concinna ticks were obtained from 35 goats, three adult H. concinna ticks (4.17 %) collected from two goats were found to be infected with SFTSV via PCR assay. Sequence analysis showed that the partial segment M glycoprotein gene of SFTSV was about 500 bases long by polymerase chain reaction (PCR) amplification and that the PCR products from the samples had an identical sequence (KP714259). With regard to the phylogenetic analysis, the Nei-Gojobri (Kimura 2-parameter) method was used to construct the phylogenetic trees. Phylogenetic analysis indicated that the obtained sequence closely resembled SFTSV strain from Zhejiang Province (KC189856) and belonged to the same clade. The similarity of these strains was up to 96.62 % (only differing by 17 bases). In addition, phylogenetic analysis also indicated that the sequence obtained from adult H. concinna ticks was most closely related to the sequence isolated from Haemaphysalis longicornis (KF781498) with 97.22 % similarity (differing only by 4 bases) and belonged to the same clade.

The worldwide circulation of H9N2 avian influenza virus in poultry, the greater than 2.3 % positive rate for anti-H9 antibodies in poultry-exposed workers, and several reports of human infection indicate that H9N2 virus is a potential threat to human health. Here, we found three mutations that conferred high virulence to H9N2 virus in mice after four passages. The PB2-E627K substitution rapidly appeared at the second passage and played a decisive role in virulence. Polymerase complexes possessing PB2-E627K displayed 16.1-fold higher viral polymerase activity when compared to the wild-type virus, which may account for enhanced virulence of this virus. The other two substitutions (HA-N313D and HA-N496S) enhanced binding to both α2,3-linked and α2,6-linked sialic acid receptors; however, the HA-N313D and N496S substitutions alone decreased the virulence of mouse-adapted virus. Furthermore, this mouse-adapted virus was still not transmissible among guinea pigs by direct contact (0/3 pairs). Our findings show that adaption in mice enhanced the viral polymerase activity and receptor-binding ability, which resulted in a virulent phenotype in mice but not a transmissible phenotype in guinea pigs, indicating that host factors play an important role in adaptive evolution of influenza in new hosts.

The objective of this study is to evaluate the effects of chromic chloride (CrCl3) on chick embryo fibroblast (CEF) viability. The cells were incubated with CrCl3 (0.02, 0.1, 0.5, 2.5, 12.5, and 62.5 μM), and the viability was determined using MTT assay, morphological detection and flow cytometry. The results show that lower concentrations of CrCl3 (0.02, 0.1, and 0.5 μM) did not damage CEF viability. At 0.1 μM, CrCl3 can increase CEF viability (P

The major virulence factor of enterohemorrhagic Escherichia coli in infections is its ability to cause attaching and effacing lesions in enterocytes, as well as to produce Shiga toxins. To clarify the pathogenic mechanism and host innate immune responses of enterohemorrhagic Escherichia coli in rabbits, experimental infections with TS and MY strains were conducted. Among the results, although the MY strain’s pathogenicity was stronger than the TS, typical symptoms were observed in both groups of bacterial-infected rabbits. Pathological changes in the heart, liver, and spleen of rabbits infected with the MY strain were more severe than those infected with the TS strain, pro-inflammatory cytokines IL-1β, IL-6, IL-8, IFN-γ, and TNF-α were induced by both strains, and α- and β-defensin were significantly upregulated at 3 d postinfection. Moreover, in the spleen, the MY strain induced greater expressions of α- and β-defensins than did the TS strain. However, in the liver, the TS strain induced greater expressions of α- and β-defensins than did the MY strain. Most likely, different replications of the MY and TS strains in the liver and spleen induced different host immune responses. Altogether, the findings provide new insights into the occurrence and development of enterohemorrhagic Escherichia coli-mediated diseases in rabbits.

To evaluate the environmental quality of different poultry houses, the concentrations and compositions of microbial aerosols and PM2.5 were measured. Results showed that the concentrations of airborne bacteria, airborne fungi and airborne Escherichia coli in poultry houses were 0.167-4.484 × 104 CFU/m3, 0.236-4.735 × 103 CFU/m3, and 0-33.0 CFU/m3, respectively. Distributions of bacteria and fungi at levels 5 and 6 of the Andersen sampler were 11.4%-34.3% and 16.8%-37.5%, respectively. Conditional pathogenic bacteria including Klebsiella pneumoniae, Staphylococcus epidermidis, Enterococcus and Aerococcus viridans, were detected at the aforementioned level, in particle sizes similar to PM2.5 and with PM2.5 concentrations in poultry houses of 114-230 μg/m3 . In PM2.5, the chief bacteria genera were Faecalibacterium, Bacteroides, and Escherichia, whereas the dominant genus of fungus was Aspergillus. Importantly, the relative abundances of Escherichia and Corynebacterium in broiler houses were 3.1% and 1.94%, respectively, which were greater than those in layer houses. However, the percentages of Aspergillus and Penicillium were 13.5% and 0.56%, with a relatively high level in layer houses . Altogether, results revealed that the ambient air quality in poultry houses had a relatively high abundance of conditional pathogenic bacteria and concentration of PM2.5, which could threaten the health of animals and workers.

Microbial aerosol whose species and concentrations are closely related to human health is ubiquitous. The effect of microbes on human and animal health and production performance is, in many cases, caused by the spreading of air. Samples in this experiment were from a live poultry market (LPM) in Tai’an, China, collected three times a day (8 am, 14 pm, and 20 pm) over three consecutive days each month for 11 months (Original sampling plan was a year, the government due to the environmental protection, the was LPM closed). The main indicators of the test were concentrations of cultural airborne bacteria, airborne fungi, and Gram-negative bacteria. At the same time the species of Gram-negative bacteria and the concentration of endotoxin were tested. Temperature and humidity were recorded in the process of each sampling. The results showed that the diurnal variation of the concentration of bacteria, fungi, and Gram-negative bacteria is higher in the morning and evening, but lower at noon. The concentrations of airborne bacteria and Gram-negative bacteria increased in earlier months and decreased in later months, with the peak appearing in the autumn. The concentration of fungi showed a decrease first and then tended to stabilize, with the peak occurring in the spring. The concentration peak of endotoxin occurred in the summer. Endotoxin levels were significantly correlated with humidity (r = 0.90, p < 0.01). Most bacteria were distributed at the third and fourth stages (2.1–4.7 μm) in the ANDERSEN-6 sampler. The dominant species of Gram-negative bacteria during the four seasons were Pseudomonas aeruginosa, Acinetobacter, Klebsiella pneumoniae, and Salmonella. In China, people have a habit of eating fresh poultry, LPM distribution is widespread, stream of people and traffic flow are large, easily caused the spread of bacteria and viruses, so the LPM microbial aerosol research have significant public health implications.

Probiotics such as Lactobacillus and Bifidobacterium have been successfully used to promote growth and prevent diseases. Previous reports have demonstrated that Bacillus subtilis (B. subtilis) was a potential probiotic for animals. In this research, 180 B. subtilis were isolated from the soil, identified and investigated in vitro. Furthermore, five B. subtilis were selected and mixed to investigate their effect on growth performance, immune response, intestine microbiota and disease resistance in rabbits. Rabbits with a diet of 106 CFU g-1 mixed B. subtilis exhibited the best growth performance, and higher serum IgG and IgA than controls (P < 0.05). Moreover, dairy with B. subtilis can promote the balance of intestinal flora. The major pro-inflammatory factor and β-defensin were up-regulated compared with the controls. After 7 weeks of feeding, the survival rate of the rabbits fed with B. subtilis was significantly higher than those in the control groups post-infected with Escherichia coli. At the same time, this study detected higher expression of β-defensin and reduced bacteria contents of the heart and cecal contents from the diet mixed with B. subtilis compared with the control groups. In conclusion, dietary supplementation with B. subtilis for rabbits could improve growth performance, serum immunoglobulin, intestinal homeostasis and immune organ index, and enhance innate immune response as well as disease resistance. These findings showed that the induction of β-defensin by B. subtilis might be an interesting new therapeutic strategy to strengthen innate defence mechanisms.

To further investigate the airborne infection mechanism of Marek's disease virus (MDV), a MDV aerosol infection model was established, and the generation, transmission and infectiosity of MDV aerosols were monitored in this study. Two positive/negative pressure isolators, in which SPF chickens were raised, were connected with a closed conduit. Two repetitive trials, Trial 1 (T1) and Trial 2 (T2) were carried out for objective assessment. Air samples were collected using the AGI-30 sampler. Viral DNA in air samples and feather follicle samples were detected using real-time quantitative PCR (QRT-PCR). MDV in air and blood samples was detected by indirect immunofluorescence assay (IFA). In chickens of isolator A (MDV inoculation group), MDV was detected in feather follicles in 100% of the tested chickens at 6 days post inoculation (dpi) in both trials; and MDV was isolated from blood samples at 9-10 dpi. MDV DNA was detected in air samples from isolator A at 12 dpi in T1 and 14 dpi in T2 and concentration of aerosolized MDV DNA was peaked at 3.84 × 10(6)copies/m(3) air at 40 dpi in T1, and 6.17 × 10(5)copies/m(3) air at 38 dpi in T2, respectively. Infectious MDV (cell culture) was isolated from isolator A at 17 in T1 and 19 dpi in T2, respectively. MDV aerosol in Isolator B was almost same as isolator A. Viremia was detected in isolator B at 26-30 dpi. The incidence of viremia in isolator B reached 70% at 3 months post inoculation. These results demonstrated that infected chicken could discharge virus, the MDV could form aerosols and infect neighboring chickens. Understanding the mechanism of generation and infection of MDV aerosols is helpful to prevent and control MD.

The study was conducted to investigate drug resistance, OXA-type carbapenemases-encoding genes and genetic diversity in airborne Acinetobacter baumannii (A. baumannii) in burn wards. Airborne A. baumannii were collected in burn wards and their corridors using Andersen 6-stage air sampler from January to June 2011. The isolates susceptibility to 13 commonly used antibiotics was examined according to the CLSI guidelines; OXA-type carbapenemases-encoding genes and molecular diversity of isolates were analyzed, respectively. A total of 16 non-repetitive A. baumannii were isolated, with 10 strains having a resistance rate of greater than 50% against the 13 antibiotics. The resistance rate against ceftriaxone, cyclophosvnamide, ciprofloxacin, and imipenem was 93.75% (15/16), but no isolate observed to be resistant to cefoperazone/sulbactam. Resistance gene analyses showed that all 16 isolates carried OXA-51, and 15 isolates carried OXA-23 except No.15; but OXA-24 and OXA-58 resistance genes not detected. The isolates were classified into 13 genotypes (A-M) according to repetitive extragenic palindromic sequence PCR (REP-PCR) results and only six isolates had a homology ≥90%. In conclusion, airborne A. baumannii in the burn wards had multidrug resistance and complex molecular diversity, and OXA-23 and OXA-51 were dominant mechanisms for resisting carbapenems.

The dissemination of drug-resistant bacteria from animal farms to aquatic environments can pose a potential threat to public health. In this study, antimicrobial resistance, resistance genes, and genetic similarity of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli of different origins (chicken feces and upstream and downstream river waters) were analyzed to track the spread of drug-resistant bacteria of animals. The results showed that a total of 29 ESBL-producing E. coli were obtained from 258 samples, and isolation rates of the ESBL-producing E. coli from chicken feces and upstream and downstream waters were 10.7% (16/150), 3.7% (1/27), and 14.8% (12/81), respectively. The ESBL-producing E. coli from upstream water was resistant to 7 antibiotics, but isolates from feces and downstream water had a higher resistance rate. In 29 ESBL-producing E. coli, the most common gene was CTX-M and the SHV gene was not detected. Five ESBL-producing isolates from downstream water showed >90% similarity with the fecal isolates, while the only one isolate from upstream water had .

H9N2 avian influenza virus has been circulating widely in birds, with occasional infection among humans. Poultry workers are considered to be at high risk of infection with avian influenza due to their frequent exposure to chickens, but the frequency of H9N2 avian influenza virus infections among them is still indistinct. This study was carried out in order to identify the seroprevalence of H9N2 avian influenza virus among poultry workers in Shandong, China. During the period from December 2011 to February 2012, a total of 482 subjects took part in this study, including 382 poultry workers and 100 healthy residents without occupational poultry exposure. Serum samples were collected and tested for the presence of antibodies against H9N2 avian influenza virus by hemagglutination inhibition (HI) and microneutralization (MN) assays. Nine subjects (9/382 = 2.3 %) were positive for antibodies against H9N2 avian influenza virus among poultry workers by either HI or MN assays using ≥40 cut-off, while none of the 100 healthy residents were seropositive. In conclusion, our study identified H9N2 avian influenza infections among poultry workers in Shandong, China, and continuous surveillance of H9N2 avian influenza virus infection in humans should be carried out to evaluate the threat to public health.

This study aimed to determine the transmission characteristics of H9N2 avian influenza viruses (AIVs) derived from the air. Eight H9N2 AIVs were isolated from chicken houses between 2009 and 2010. We analyzed the phylogenic and pathogenic traits of these isolates. What is more, transmission characteristics in guinea pigs of two airborne isolates were determined in experimental conditions. Phylogenetic analyses indicated that the homologies of HA and NA genes of eight isolates were 95.4-99.7% and 86.6-99.8% respectively. They were able to duplicate in lung tissues of guinea pigs without prior adaptation. Two airborne isolates could both transmit among guinea pigs by direct contact. No infection was detected in aerosol contact animals while H9N2 AIV aerosols were detected in the air of isolators. Aerosol infection dose experiment showed that aerosol median infective dose (ID(50)) of H9N2 AIV to guinea pigs was 3.58×10(6)copies, demonstrating that the aerosols could infect guinea pigs at certain concentrations in experimental condition. In conclusion, H9N2 AIV aerosols were infectious to mammals, suggesting that urgent attention will need to be paid to its transmission.

Mitochondrial antiviral-signaling protein (MAVS), an adaptor protein of retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs)-mediated signal pathway, is involved in innate immunity. In this study, Cherry Valley duck MAVS (duMAVS) was cloned from the spleen and analyzed. duMAVS was determined to have a caspase activation and recruitment domain at N-terminal, followed by a proline-rich domain and a transmembrane domain at C-terminal. Quantitative real-time PCR indicated that duMAVS was expressed in all tissues tested across a broad expression spectrum. The expression of duMAVS was significantly upregulated after infection with duck Tembusu virus (DTMUV). Overexpression of duMAVS could drive the activation of interferon (IFN)-β, nuclear factor-κB, interferon regulatory factor 7, and many downstream factors (such as Mx, PKR, OAS, and IL-8) in duck embryo fibroblast cells. What is more, RNA interference further confirmed that duMAVS was an important adaptor for IFN-β activation. The antiviral assay showed that duMAVS could suppress the various viral replications (DTMUV, novel reovirus, and duck plague virus) at early stages of infection. Overall, these results showed that the main signal pathway mediated by duMAVS and it had a broad-spectrum antiviral ability. This research will be helpful to better understanding the innate immune system of ducks.

Given the promising results of applying Bacillus subtilis (B.subtilis) as a probiotic in both humans and animals, the aim of this study was to systematically investigate the effects of B. subtilis on growth performance, immune response and disease resistance in Cherry Valley ducks. At 28 d post-hatch (dph), ducks fed a diet with B. subtilis weighed significantly more, had higher relative immune organ weights (e.g., bursa of Fabricius, thymus, and spleen), and exhibited greater villus heights, villus height to crypt depth ratios (duodenum and jejunum), and shallower crypt depths in the duodenum than controls fed a normal diet (p < 0.05). Moreover, the major pro-inflammatory factors and antiviral proteins, as measured in the thymus and the spleen, were higher at 28 dph in ducks fed probiotics than those of 14 dph. After 28 d of feeding, the ducks were challenged with Escherichia coli (E. coli) and novel duck reovirus (NDRV), and ducks fed B. subtilis achieved survival rates of 43.3 and 100%, respectively, which were significantly greater than the control group's 20 and 83.3%. Altogether, diets with B. subtilis can improve Cherry Valley ducks' growth performance, innate immune response, and resistance against E. coli and NDRV.