Pasteurella multocida causes fowl cholera which is an economically important disease in poultry industries around the world. In this study, we analyzed the capsular genotype, lipopolysaccharide (LPS) genotype, virulence-associated genes (VAGs) patterns, antimicrobial resistance and genetic diversity in a total of 9 P. multocida isolates from poultry with fowl cholera between 2014 and 2019 in Korea. When combining the capsular types with the LPS genotypes, two isolates of the 9 isolates were A:L3, and the others were non-typeable (NT): L3. Of the 23 VAGs, all the isolates harbored ptfA, fimA, hsf-1, hsf-2, pfhA, exbB, exbD, tonB, hgbA, hgbB, fur, sodA, sodC, pmHAS, ompA, ompH, oma87, plpB, psl, and nanH, whereas toxA gene was not detected in any of the 9 isolates. In addition, among the 11 antimicrobials, most of the isolates except for one isolate resistant to florfenicol, exhibited susceptibility to all the antimicrobials. Multi-locus sequence typing (MLST) analysis revealed 5 different sequence types (ST): ST8, ST351, ST352, ST353, and ST368. The ST351, ST352, ST353, and ST368 were identified for the first time in this study, and ST352 and ST353 isolates were largely prevalent nationwide. These STs isolates should be monitored continuously because in some cases, ST352 and ST353 isolates demonstrated high mortality rates. Although only limited numbers of isolates have been analyzed, our findings provide overall characteristics and epidemiological information of the P. multocida strains recently prevalent in Korea.

Virulent Escherichia coli strains have commonly been associated with diarrheal illness in humans and animals. Typical enteropathogenic Escherichia coli (EPEC) with intimin gene (eaeA) and E. coli adherence factor plasmid, or atypical EPEC with only eaeA have been implicated in human cases. In the present study, we investigated the prevalence of virulence-associated genes including eaeA in the E. coli strains isolated from cloacal specimens of 184 chicken flocks in 7 provinces in Korea between 2009 and 2010. When 7 virulence genes (VT1, VT2, LT, and ST for enterotoxigenic E. coli; eaeA and bfpA for enteropathogenic E. coli; and aggR for enteroaggregative E. coli) were screened by multiplex PCR, a total of 30 E. coli strains carrying only the eaeA gene were detected from 184 flocks that were identified as atypical enteropathogenic Escherichia coli (aEPEC). The aEPEC strains were analyzed by eae subtyping, phylogenetic grouping PCR, and serotyping. Twelve (40%) of 30 aEPEC strains possessed an eae-β subtype, followed by θ (30%), ε (16.7%), and β1 (13.3%). Eight (26.7%) of 30 aEPEC strains were designated into the phylogenetic group A. Two (6.7%) and 3 (10%) aEPEC strains were classified into the phylogenetic group B2 and D, respectively. A total of 15 (50%) aEPEC strains were serotyped to groups O24, O25, O26, O71, O80, O103, and O157, and the remaining strains were nontypeable. In analyzing the genetic diversity among the 30 aEPEC isolates by the pulsed-field gel electrophoresis method with XbaI-digestion, the pulsed-field gel electrophoresis profiling produced 20 different patterns, but isolates within the same group did not show clear geographic or breed relationships. Our data indicate that healthy chickens may constitute an important natural reservoir of aEPEC strains, and suggest that transmission to humans could not be excluded.

The aims of this study were to determine if the chicken embryo lethality assay and the presence of 9 virulence-associated genes of Escherichia coli were correlated and to discover which virulence genes contributed most to embryo lethality. We examined 58 E. coli strains isolated from visceral organs of chickens with colibacillosis for the presence of 9 virulence genes (fimC, tsh, fyuA, irp2, iucD, cvi/cva, iss, astA, and vat) by PCR. The gene FimC (type I fimbriae) was detected with the highest prevalence in 93.1% of the isolates, followed by iucD (67.24%), iss (58.62%), tsh (34.48%), cvi/cva (34.48%), fyuA (32.76%), astA (31.0%), irp2 (27.59%), and vat (17.24%). The embryo mortality ranged from 5 to 100%; however, most of the isolates were moderately or highly virulent. High positive correlations were observed between the presence of virulence genes and chicken embryo lethality. In addition, presence of the iucD (aerobactin) gene was the trait that best contributed to embryo mortality by using the multivariate model. These results suggest that expression frequency of these 9 virulence genes is associated with embryo mortality, and the gene that best predicted embryo mortality was iucD.

The present study reports on layer chickens with colibacillosis in 2 commercial egg-producing farms (referred to as farm A and farm B, which were managed by the same owner and were about 1 km apart) in the middle region of the Korean peninsula. The 2 flocks were infected at the initiation of egg laying. They were characterized by no previous clinical signs but sudden mortality (2.7-4.0%), with severe lesions of septicemia and fibrinous polyserositis. Escherichia coli was isolated from the lesions of the infected birds. Serotyping tests identified isolates that belonged to somatic groups O1 (12/17), O46 (2/17), O78 (1/17), and O84 (1/17) or that were unidentified (1/17). Thirteen of 17 E. coli isolates (76.4%) obtained from 11 birds in the 2 flocks showed similar pulsed-field gel electrophoresis patterns that were arbitrarily designated as pattern A. The isolates had high frequencies of putative virulence genes including 100% [fimC (type 1 fimbriae), iucD (aerobactin synthesis), and iss (increased serum survival)], 94.1% [cva/cvi (structural genes of colicin V operon) and vat (vacuolating autotransporter toxin)], 88.2% [irp2, iron-repressible protein (yersinia bactin) synthesis, and fyuA, ferric yersinia uptake], and 82.3% [tsh (temperature-sensitive hemagglutinin)]; astA (encoding a heat-stable cytotoxin associated with enteroaggregative E. coli) was not associated with the enteric disorder. These data suggest that all chickens with colibacillosis on farms A and B were likely infected by E. coli strains that are highly pathogenic in avian species.

Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) has been associated with morbidity and mortality in broiler chickens worldwide. The present study described purulent arthritis of broilers infected with Salmonella Enteritidis and investigated antibiograms and genetic characteristics of Salmonella Enteritidis isolates from epidemiologically related properties such as a hatchery and breeder farm in an attempt to elucidate the source of contamination. Clinical disease and mortality were observed in the affected broiler flock. Mortality was 5.8% until 12 d of age. The birds typically showed lameness with moderately swollen hock joints and footpads. The most prevalent lesions were severely purulent arthritis with polyserositis. Histopathology revealed moderate to severe inflammation in the synovial membrane of leg joints and visceral organs. When the antimicrobial susceptibility test was performed against 7 isolates of Salmonella Enteritidis from broilers, and relevant hatchery and breeder farms by the disk diffusion method using 18 antimicrobial agents, isolates from broiler and breeder farms had the same antibiogram characterized by multiple drug resistance to ampicillin, ceftiofur, cephalothin, gentamycin, nalidixic acid, streptomycin, sulfisoxazole, and tetracycline, whereas isolates from the hatchery were differently resistant to only nalidixic acid. Through the genetic analysis with pulsed-field gel electrophoresis using the restriction enzyme XbaI, Salmonella Enteritidis isolates from both broiler and breeder farms also showed the same PFGE pattern compared with the hatchery isolates resistant to nalidixic acid. As a result, the same PFGE profiles and antibiogram patterns among isolates from broilers and breeder farms provided direct evidence of vertical Salmonella Enteritidis transmission from the contaminated breeder farm to commercial broiler.

Salmonella enterica serovar Gallinarum (Salmonella Gallinarum) is the causative agent of fowl typhoid (FT), a severe systemic disease of chickens that results in high mortality. Since 1992, FT has become one of the most serious bacterial diseases in poultry in Korea. The purpose of this study was to investigate the prevalence of FT during 2000 to 2008 and characterize the phenotype and genetic diversity of Salmonella Gallinarum isolates before and after adopting national-wide vaccination with a live attenuated strain (SG 9R) in 2001. For 9 yr, a total of 983 farms were affected with FT outbreaks, and after reaching a peak in 2002 (206 farms affected), the prevalence of the disease gradually declined, whereas magnitude sales of the vaccine increased every year. According to the analysis based on the chicken breeds (n=521 farms), the incidence of FT in commercial broilers, Baeksemi (a mixed breed of male meat-type breeder and female commercial layer), commercial layers, native chickens, and broiler breeders was 47.7, 28.4, 17.2, 5.1, and 1.3%, respectively. Of the affected broilers, over 90% birds were under 2 wk of age, indicating it was possible that they were infected with Salmonella Gallinarum via vertical transmission. In the phenotypic analysis, Salmonella Gallinarum strains (n=142) isolated during 2001 to 2007 showed the same pattern in the majority of the biochemical tests such as carbohydrate fermentation and amino acid decarboxylation. Interestingly, all of the strains could not ferment rhamnose, but SG 9R could, making rhamnose a potential biomarker to distinguish the vaccine strain. In analyzing the genetic diversity by the pulsed field gel electrophoresis method with XbaI digestion, we examined a total 68 isolates of Salmonella Gallinarum obtained in 5 provinces in Korea (2001 to 2007). The pulsed field gel electrophoresis profiling produced 7 different patterns, but isolates within the same group did not show clear geographic or breed relationships. In conclusion, there were close epidemiological linkages between prevalence of FT and the sales volume of the live FT vaccine in Korea. In addition, a low phenotypic and genetic heterogeneity was observed among Korean Salmonella Gallinarum isolates and the live vaccine strain (SG 9R).

Korean wild magpies (Pica pica sericea) were intranasally inoculated with highly pathogenic avian influenza (A/Chicken/Korea/ES/03 virus) (H5N1), which was classified as clade 2.5. We estimated viral replication, death after infection, and histology and immunohistochemistry. This species was highly susceptible to severe infection; 100% of birds died within 5 to 8 d. The virus was detected from oropharyngeal (1 to 5 d postinfection) and cloacal (3 to 5 d postinfection) swabs from infected magpies. At necropsy, the prominent lesions were coalescing necrosis of the pancreas with enlargement of livers and spleens. Microscopically, pancreas, brain, heart, adrenal gland, and kidney were most consistently affected with necrotic and inflammatory changes, and viral antigen was frequently demonstrated in the parenchyma of these organs. As a result, Korean wild magpies were very susceptible to avian influenza (H5N1) virus.

The live attenuated vaccine against duck viral hepatitis currently available in Korea requires special freezers for storage and transportation with extra costs involved. The development of a lyophilization stabilizer for live attenuated duck viral hepatitis virus (DHV) vaccines, therefore, has been highly recommended for the wider application of the vaccines. Four conventional vaccine stabilizer formulations containing a disaccharide, such as lactose, trehalose, or sucrose, and new formulations containing sorbitol were tested for their efficacy in stabilizing a new attenuated DHV type 3 vaccine candidate under different storage temperatures, 4 and 37 degrees C. The vaccine virus and each stabilizer formulation were combined and submitted to lyophilization and the viability of the virus was measured in 7-d-old specific-pathogen-free chicken embryos by determining the 50% egg lethal dose. Stabilizer formulations containing 2, 4, or 8% sorbitol preserved the viability of the vaccine virus much better than the other stabilizer formulations and 2% sorbitol was the optimal concentration in a standard stabilizing buffer, phosphate glutamate gelatin (0.0038 M KH2PO4, 0.0071 M K2HPO4, 0.0049 M monosodium L-glutamate, and 0.5% gelatin). The results demonstrate that the stabilizer formulation containing 2% sorbitol and 0.5% gelatin can be used for convenient storage and transportation of live DHV vaccines.

Park, S.; Kim, Y. H.; Yoon, Y.; shin, J. W.; Kang, M. S.; Shin, J. W. Author Information

A 73-year-old man was admitted with dyspnoea and facial oedema. He was previously healthy with a smoking history of 40 pack-years. A CT scan of the chest showed a peribronchial soft tissue mass in the central portion of the right upper lobe and conglomerated enlarged multiple lymph nodes in the right hilar, subcarinal, paratracheal and prevascular areas with superior vena cava (SVC) obstruction (fig 1A). A …

The application of an immune algorithm for the optimal switching search problem to achieve loss minimisation and loading balance among feeders and main transformers is presented. This algorithm prevents the possibility of stagnation in the iteration process and achieves fast convergence for global optimisation. The efficiency of the immune algorithm to solve the problem is verified by comparing the computing time of the conventional binary integer programming for decision making of the switching operation. An interactive best-compromise method is also applied to solve the multiobjective distribution-feeder reconfiguration. Quantitative measures can be supplied to aid the decision-making process. A Taipower distribution system with 18 feeders is selected for computer simulation to demonstrate the effectiveness of the proposed methodology for solving the optimal-switching operation of distribution systems to minimise the power loss and simultaneously enhance the loading balance.

The unbounded fairness problem of WFQ induced by handovers in cellular packet switched networks is investigated and a new strategy for guaranteed bounded fairness is proposed. The simulation results show that the proposed scheme maintains bounded fairness, while in WFQ an increase in unfairness from a handover is cumulative, allowing a new flow to monopolise a wireless link in proportion to the increase.

In this paper, one of the geographic information management system(GIS) is applied to perform the automated mapping and facility management (AM/FM) of power distribution systems for contingency load transfer. Three phase load flow analysis is used to calculate the current flows of line switches by retrieving the network topology and facility attributes which have been stored in the AM/FM database. The current flows solved are then stored in the database as the attributes of line switches for load transfer analysis. When a system contingency such as fault or overload occurs, the load transfer is then executed to find the switches to be operated by the heuristic search method while subjected to the system operation rules. By the proposed method, the network topology can be easily updated and displayed in the computers by connectivity trace routine according to the switching operations. Since all the system facilities are stored in the AM/FM database according to the actual spatial coordinates, it provides practical information for the system operators and crews to allocate and operate the switches easily. To demonstrate the effectiveness of the integrated AM/FM system with application programs for distribution operation, a distribution system of Taiwan Power Company(Taipower) in Kaohsiung downtown area is selected for case study. It is found that contingency load transfer for distribution system operation can be enhanced 'significantly with the application of AM/FM systems to determine the switches to be operated and the corresponding spatial locations of the switches. The impact of load transfer to the system voltage profile and the feeder loading can also be analyzed to provide valuable information for the system operators.

In this paper, an automated mapping and facility management (AM/FM) system is integrated with the emergency switching operation routine which is based on the field expertise experience of distribution systems. Since the voluminous data and combinatorial characteristic of switching problems of distribution systems, the sophisticated man-machine interface and rule-based methodology provide high benefit of reality. The database construction and feeder connectivity tracing in the AM/FM database and heuristic rules for the interfeeder switching operations are proposed. A practical distribution system of downtown area is tested to identify the efficiency of the proposed method. In case a system fault occurs, the contingency switching process by retrieving the related facility information in the AM/FM database will providing a very effective tool for the distribution operators by providing not only the switching process to be executed but also the spatial location of system facility to be operated.<>

By treatment with detergent and NaCl, particulate (1----3)-beta-D-glucan synthase (EC 2.4.1.34) from Hansenula anomala or Neurospora crassa was dissociated into a "soluble fraction" and a "membrane fraction." Each fraction alone was almost inactive, but enzymatic activity could be reconstituted by mixing the two fractions and adding GTP or one of its analogs. Based on their lability to heat and to incubation with trypsin, the activity in both fractions is proteinaceous. The active component in the soluble fraction appears to bind guanosine 5'-[gamma-thio]triphosphate (GTP[gamma S]), since it was specifically protected by this nucleotide against heat inactivation and against inactivation in the presence of EDTA. Furthermore, precipitation of the soluble component with ammonium sulfate in the presence of GTP[gamma S] gave rise to a fraction that was highly active in the absence of added nucleotide, indicating either tight binding or covalent interaction between GTP[gamma S] and the soluble component. The membrane fraction probably contains the catalytic moiety, because it was partially protected against heat inactivation by the substrate, UDP-glucose. Soluble fractions that stimulated membrane fractions from H. anomala and N. crassa were obtained from several other fungi, including Saccharomyces cerevisiae. We propose that the soluble fraction contains a GTP-binding protein that modulates the biosynthesis of (1----3)-beta-D-glucan of fungal cell walls and probably has a major role in the regulation of cell wall morphogenesis.

The indolizidine alkaloid, swainsonine, was previously shown to be a potent inhibitor of lysosomal and jack bean alpha-mannosidase (Dorling, Huxtable, Colegate 1980 Biochem J 191: 649-651). We examined the effects of various concentrations of this alkaloid on a number of commercially available glycosidases and found swainsonine to be quite specific for alpha-mannosidase (50% inhibition at 1-5 x 10(-7) molar). Optimum inhibition was observed after a 2-minute preincubation of enzyme and inhibitor. Lineweaver-Burk plots of substrate concentration versus velocity in the presence of various amounts of swainsonine showed considerable curvature at high substrate concentrations, suggesting that swainsonine may be a competitive inhibitor that binds tightly to the enzyme and is only slowly removed. Periodate oxidation of swainsonine completely destroyed its inhibitory activity.