Molecular and genomic features of Mycobacterium bovis strain 1595 isolated from Korean cattle

The aim of this study was to investigate the molecular characteristics and to conduct a comparative genomic analysis of Mycobacterium (M.) bovis strain 1595 isolated from a native Korean cow. Molecular typing showed that M. bovis 1595 has spoligotype SB0140 with mycobacterial interspersed repetitive units-variable number of tandem repeats typing of 4-2-5-3-2-7-5-5-4-3-4-3-4-3, representing the most common type of M. bovis in Korea. The complete genome sequence of strain 1595 was determined by single-molecule real-time technology, which showed a genome of 4351712 bp in size with a 65.64% G + C content and 4358 protein-coding genes. Comparative genomic analysis with the genomes of Mycobacterium tuberculosis complex strains revealed that all genomes are similar in size and G + C content. Phylogenetic analysis revealed all strains were within a 0.1% average nucleotide identity value, and MUMmer analysis illustrated that all genomes showed positive collinearity with strain 1595. A sequence comparison based on BLASTP analysis showed that M. bovis AF2122/97 was the strain with the greatest number of completely matched proteins to M. bovis 1595. This genome sequence analysis will serve as a valuable reference for improving understanding of the virulence and epidemiologic traits among M. bovis isolates in Korea.

Phylogeographical characterization of H5N8 viruses isolated from poultry and wild birds during 2014–2016 in South Korea

During 2014–2016 HPAI outbreak in South Korea, H5N8 viruses have been mostly isolated in western areas of the country, which provide wintering habitats for wild birds and have a high density of poultry. Analysis of a total of 101 Korean isolates revealed that primitive H5N8 viruses (C0 group) have evolved into multiple genetic subgroups appearing from various epidemiological sources, namely, the viruses circulating in poultry farms (C1 and C5) and those reintroduced by migratory birds in late 2014 (C2 and C4). No C3 groups were detected. The results may explain the possible reasons of the recent long-term persistence of H5N8 viruses in South Korea, and help to develop the effective measures in controlling HPAI viruses.

Biological Property of Recombinant Hemagglutinin-Neuraminidase Protein of Avian Paramyxovirus Type 6 Expressed by Recombinant Baculovirus

Hemagglutination inhibition (HI) test employing whole virus antigen is a prescribed serological test for serotyping, diagnosis and surveillance for avian paramyxoviruses (APMVs). For use as alternative to the virus antigen, hemagglutinin-neuraminidase (HN) protein gene of the wild duck isolate APMV-6/WB12-163FS of APMV serotype 6 (APMV-6) was amplified, cloned and expressed in Spodoptera frugiperda insect cells. The HN gene of 1,842 bps in length showed nucleotide and amino acid homology of 93.4% and 97.1%, respectively with that of APMV-6 prototype strain. Putative sialic acid binding motif and potential N-linked glycosylation sites were conserved. In Western blot analysis, the expressed protein had a molecular mass of 66 kDa and reacted specifically with antiserum to APMV-6. In addition, the recombinant HN protein showed biological properties such as hemagglutination (HA) and elution. The recombinant HN protein produced from infected cells showed high HA titers (approximately 2(13) HA unit/ml). The HA activity of the recombinant HN protein was inhibited by antisera to APMV-6. In cross HA inhibition test, the recombinant HN protein had the highest titers with antisera to homologous APMV serotype, although there was weak cross reaction with some of antisera to other APMV serotypes. Our results indicated that recombinant APMV-6 HN protein would have the potential as alternative to the APMV-6 antigen in HI assays.

Pathogenicity of H5N8 virus in chickens from Korea in 2014

In 2014, two genetically distinct H5N8 highly pathogenic avian influenza (HPAI) viruses were isolated from poultry and wild birds in Korea. The intravenous pathogenicity indices for the two representative viruses were both 3.0. Mortality of chickens intranasally inoculated with the two H5N8 viruses was 100% with a mean death times of 2.5 and 4.5 days. Mortality rates of the contact groups for the two H5N8 viruses were 33.3% and 66.6%. Our study showed that transmissibility of the novel H5N8 viruses was different from that of previously identified H5N1 HPAI viruses, possibly due to genetic changes.

Changes of characterization of Salmonella Typhimurium isolate following sequential exposures to porcine neutrophil / 대한수의학회지

To develop a live vaccine candidate using an attenuated strain of Salmonella Typhimurium (ST), biochemical properties, plasmid profile, PFGE patterns and pathogenic analysis of the ST isolate were carried out after sequential passage of the ST isolate in porcine neutrophils. By the passage, the ability of the neutrophil-adapted isolate to utilize d-xylose was lost, while the ability of the strain to ferment trehalose was delayed after 2 or more days of the culture. Also, changes including deletion of the gene fragments were observed in PFGE analysis of the neutrophil-adapted isolates. Two plasmids, 105kb and 50kb, were cured in the strain passaged over 15 times in porcine neutrophils. The 50% of lethal dose (LD50) of the parent strain was changed from 1 x 10(5) LD50 to 6 x 10(6) LD50 by the passage in intraperitoneal injection of the strains into mice. These results suggested that bacterial genotypic and phenotypic responses might be globally altered depending on the inside environment of neutrophils.

Isolation, characterization, and evaluation of Bacillus thuringiensis isolated from cow milk / 대한수의학회지

Probiotics colonize the intestines and exert an antibacterial effect on pathogens. Therefore, probiotics could be used as a preventive agent against lethal infections. To isolate probiotic microorganisms, 116 bacterial strains were isolated from healthy cow's milk and were subjected to Gram-stain, morphology and biochemical analyses, Vitek analysis, and 16S rRNA analysis. One of the strains identified as Bacillus (B.) thuringiensis 87 was found to grow very well at pH 4.0~7.0 and to be resistant to high concentrations of bile salts (0.3~0.9% w/v). B. thuringiensis was susceptible to the antibiotics used in the treatment of bovine mastitis, yet it exhibited an antimicrobial effect against Staphylococcus (S.) aureus 305. Moreover, it protected mice from experimental lethal infections of E. coli O55, Salmonella typhimurium 01D, and S. aureus 305 through a significant induction of interferon-gamma, even at four-week post-administration of B. thuringiensis. Although oral administration of B. thuringiensis 87 did not provide significant protection against these lethal challenges, these results suggest that B. thuringiensis 87 could be a feasible candidate as a probiotic strain.

A novel mycotoxin purification system using magnetic nanoparticles for the recovery of aflatoxin B1 and zearalenone from feed

In this study, we developed a novel tool for purifying two mycotoxins, aflatoxin B1 (AFB1) and zearalenone (ZEN), in feed. This system utilized monoclonal antibodies (mAbs) against AFB1 and ZEN, and magnetic nanoparticles (MNPs). Among ten MNPs with different diameters and functional groups, a 100-nm diameter MNP (fMA) conjugated to an amine group (-NH2) was found to be optimum for coupling with mAbs. The optimal mAb concentrations for coupling to the fMA along with mycotoxin purification capacities of the fMA-mAb conjugates (fMA-AFB1 and fMA-ZEN) were determined. A comparison of mean recovery rates (from corn and product X feed) between the fMA-mAb conjugates and immunoaffinity columns (IAC-AFB1 and IAC-ZEN) showed that the rate for fMA-AFB1 (90~92% and 81~88%) was higher (p > 0.05) than that of IAC-AFB1 (81~84% and 72~78%) for AFB1 (5, 10, 15 ng/mL), and the rate for fMA-ZEN (99~100% and 92~94%) was significantly higher (p 30 min). This study suggests that the novel purification system we developed would be a useful tool for monitoring and regulating mycotoxin contamination in feed, and replace IAC methods.

Prevalence and antimicrobial susceptibility of Brachyspira species in pigs in Korea / 대한수의학회지

The purpose of this study was to investigate the prevalence of Brachyspira species and antimicrobial susceptibility of Brachyspira (B.) hyodysenteriae isolates in Korea. A total of fifty-five Brachyspira species were isolated; five (1.0%) beta-hemolytic Brachyspira species and 50 (10.4%) weak hemolytic Brachyspira species from 116 different diarrheic pig samples and 367 apparently normal pig samples. In farm level, beta hemolytic and weak hemolytic Brachyspira species were detected in 7.4% (5/68) and 19.1% (13/68) of tested pig farms, respectively. By phenotypic and genotypic characterization, all beta hemolytic Brachyspira isolates was classified as group I (B. hyodysenteriae), whereas weak hemolytic Brachyspira species isolates were group III (B. innocens or B. murdochii). B. hyodysenteriae isolates showed high level of minimum inhibition concentrations to macrolide antimicrobials. This study shows that the prevalence of pathogenic B. hyodysenteriae in pigs is low but antimicrobial resistance of the pathogens is high in Korea. This is the first report of the prevalence of Brachyspira group III and antimicrobial susceptibility of B. hyodysenteriae in pigs in Korea. Our results could provide basic data for the management and treatment guidelines of Brachyspira infection.

Modular Cementless Total Hip Arthroplasty with Subtrochanteric Shortening Osteotomy in Patients with High Hip Dislocation

PURPOSE: The purpose of this study was to report on the results of performing modular cementless total hip arthroplasty with a simultaneous subtrochanteric shortening osteotomy in patients with high hip dislocation. MATERIALS AND METHODS: We evaluated 23 patients (24 hips) with high hip dislocation and who had undergone total hip arthroplasty using a proximally modular cementless stem in combination with a subtrochanteric shortening osteotomy in order to place the acetabular cup at the level of the anatomic hip center between May 1996 and June 2008. There were 6 males and 17 females with a mean age of 44 years. The mean duration of follow-up was 5.6 years. RESULTS: The mean Harris hip score improved from 53 points preoperatively to 88 points at the time of final follow-up (P<0.001), and there were good or excellent results in 21 hips (87.5%). There was one instance of isolated loosening of the acetabular component. With the exception of one hip requiring revision surgery at 12 years postoperatively because of polyethylene wear and cup loosening, all the remaining components were well-fixed at the time of the last follow-up. A total of 4 hips (17%) had complications during follow-up; one dislocation, two transient femoral nerve palsies and one nonunion of the subtrochanteric osteotomy site. CONCLUSION: Modular cementless total hip arthroplasty with a subtrochanteric shortening osteotomy in patients with high hip dislocation was associated with excellent clinical outcomes while it minimized additional fixation of the osteotomy site.

A multiplex real-time PCR for differential detection and quantification of Salmonella spp., Salmonella enterica serovar Typhimurium and Enteritidis in meats

Salmonella (S.) Typhimurium and S. Enteritidis are the major causative agents of food-borne illnesses worldwide. Currently, a rapid detection system using multiplex real-time polymerase chain reaction (PCR) has been applied for other food-borne pathogens such as Escherichia coli, Staphylococcus aureus and Streptococcus spp. A multiplex real-time PCR was developed for the simultaneous detection of Salmonella spp., especially S. Typhimurium and S. Enteritidis, in beef and pork. For the specific and sensitive multiplex real-time PCR, three representative primers and probes were designed based on sequence data from Genbank. Among the three DNA extraction methods (boiling, alkaline lysis, and QIAamp DNA Mini Kit), the QIAamp DNA Mini Kit was the most sensitive in this study. The optimized multiplex real-time PCR was applied to artificially inoculated beef or pork. The detection sensitivity of the multiplex real-time PCR was increased. The specificity of the multiplex real-time PCR assay, using 128 pure-cultured bacteria including 110 Salmonella isolates and 18 non-Salmonella isolates, was 100%, 100% and 99.1% for Salmonella spp., S. Typhimurium and S. Enteritidis, respectively. The sensitivity was 100%, 100% and 91.7% for Salmonella spp., S. Typhimurium and S. Enteritidis, respectively. The multiplex real-time PCR assay developed in this study could detect up to 0.54 +/- 0.09 and 0.65 +/- 0.07 log10 CFU/ml for S. Typhimurium and S. Enteritidis for beef, 1.45 +/- 0.21 and 1.65 +/- 0.07 log10 CFU/ml for S. Typhimurium and S. Enteritidis for pork, respectively, with all conditions optimized. Our results indicated that the multiplex real-time PCR assay developed in this study could sensitively detect Salmonella spp. and specifically differentiate S. Typhimurium from S. Enteritidis in meats.

A study on epidemiological characteristics and control methods of EHEC infection in Korea / 한국역학회지

E. coli is a bacterium that is commonly found in the gut of humans and warm-blooded animals. Most strains of E. coli are harmless. But some strains such as Enterohaemorrhagic E. coli(EHEC), can cause severe food borne disease. It is transmitted to humans primarily through consumption of contaminated foods, such as raw or undercooked ground meat. There is no widely agreed definition of when a shiga-toxin producing E. coli is considered to be an EHEC. But in Korea, the word "EHEC", "STEC", "VTEC" are often used as same meaning, which refer to the E.coli those producing shiga-toxin. We suggest the term STEC refers to those E. coli produce one or more shiga-toxins(stx), and the term EHEC refers only to STEC that cause a clinical illness. EHEC infection were designated as the class 1 notifiable disease in Korea in 2000. Although EHEC/STEC cases were not common in Korea, the number of STEC infection cases reported has increased since 2001. From 2001 to 2004, the number of STEC infection cases in Korea were 11, 8, 52, 118 respectively. These cases included 17 due to E. coli O157, 136 due to E. coli, serogroup non-O157, and 15 due to E. coli that were not serogrouped. The most common serotype implicated is E. coli O91 without virulent factor and clinical symptoms. But those cases involve in one epidemic in primary school in 2004. STEC infections in Korea occur in all age groups, with the highest frequencies in children less than 5 years old. Healthy cattle are the main animal reservoir for STEC and they harbor the organism as part of the bowel flora. The proportion of STEC in E. coli in animal feces was examined by using stool samples from 283 Korean beef cattle on 27 farms, 169 milk cattle on 28 frams, 455 swine on 50 farms. As determined by culture and toxin assay, the proportion of STEC was 25.8%(16 STEC/62 E. coli) in milk cattle, 18.8%(19 STEC/101 E.coli) in Korean beef cattle, 14.0%(25 STEC/178 E. coli) in swine. Effective surveillance of EHEC/STEC in humans is essential in order to protect the public health. EHEC infection is notifiable in many countries including USA, Japan, and Belgium, Finland, Italy, Netherlands, and the United Kingdom(UK), have sentinel systems. England, Wales, and Scotland have comprehensive national laboratory reporting schemes for STEC. And there has been an increase in the number of reported cases and outbreaks during the past decades in many countries Prevention of STEC infection requires control measures at all stages of surveillace, investigations and special pathogen tracing such as PulseNet.

Adenomyoma of the small intestine: a rare cause of intussusception in an infant

No abstract available.

A clinical study of 5-year survival rate of stomach cancer according to postoperative anticancer chemotherapy / 대한암학회지

No abstract available.

A clinical study of blunt abdominal trauma sustained from motor-vehicle accident

No abstract available.