• Korean Journal of Veterinary Research
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• v.41 no.2
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• pp.177-188
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• 2001

Mastitis is one of the most significant cause of economic loss to the dairy industry. Especially, Staphylococcus aureus is a major contagious mastitis-causing pathogen in dairy cattle. Because of its high transmission rate and resistance to antibiotic therapy, staphylococcal mastitis presents a constant threat to the dairy industry. Staphylococcal enterotoxin C(SEC) produced by S aureus has been known as one of superantigens which are able to stimulate a large proportion of T lymphocytes independently of their antigenic specificity. In this experiment, we have conducted preliminary studies with mice and lactating cows to evaluate the immunogenicity and safety of the experimental vaccine consists of SEC mutant antigen on controlling the bovine mastitis associated with S aureus infections. The average value of somatic cell counts in quarter milk, isolation rate of S aureus were consistently decreased in SEC-SER vaccinated groups, whereas antibody titers were highly increased in SEC-SER vaccinated groups. Peripheral blood were also collected from the lactating cows to determine the proportion of leukocyte subpopulation associated with humoral immunity(HI) and cell mediated immunity(CMI). Proportion of leukocyte subpopulation expressing $BoCD2^+$(total T lymphocyte), $BoCD4^+$(T helper cell), $BoCD8^+$(T cytotoxic/suppressor cell) and NonT/NonB lymphocyte which are involved in CMI in SEC-SER vaccinated groups were decreased for the initial stage after first vaccination and then increased from ten weeks after first vaccination maintaining elevated level till 14 weeks after vaccination. In contrast, proportion of monocyte, MHC class II and B lymphocyte which are associated with the production of primary immune response in SEC-SER vaccinated groups were increased for the initial period and then decreased from ten weeks after first vaccination. We present evidence that vaccination of SEC-SER mutant antigen in lactating cows induced a significant proliferation of bovine T lymphocytes. These results suggest that SEC-SER mutant antigen used in this experiment might be one of potential immunogen in developing innovative vaccine against bovine IMI associated with S aureus. Additional challenge trials should be carried out to evaluate substantial protection against S aureus under the commercial farm conditions.

• Journal of Food Hygiene and Safety
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• v.38 no.4
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• pp.193-201
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• 2023

Antimicrobials in human medicine are classified by The World Health Organization (WHO) into three groups: critically important antimicrobials (CIA), highly important antimicrobials (HIA), and important antimicrobials (IA). CIA are antibiotic classes that satisfy two main criteria: that they are the sole or the only available limited therapeutic option to effectively treat severe bacterial infections in humans (Criterion 1), and infections where bacteria are transmitted to humans from non-human sources or have the potential to acquire resistance genes from non-human sources (Criterion 2). WHO emphasizes the need for cautious and responsible use of the CIA to mitigate risk and safeguard human health. Specific antimicrobials within the CIA with a high priority for management are reclassified as "highest priority critically important antimicrobials (HP-CIA)" and include the 3^rd generation of cephalosporins and the next generation of macrolides, quinolones, glycopeptides, and polymyxins. The CIA list is the scientific basis for risk assessment and risk management policies that warrant using antimicrobials to reduce antimicrobial resistance in several countries. In addition, the CIA list ensures food safety in the food industry, including for the popular food chain companies McDonald's and KFC. The continuous update of the CIA list reflects the advancement in research and emerging future challenges. Thus, active and deliberate evaluation of antimicrobial resistance and the construction of a list that reflects the specific circumstances of a country are essential to safeguarding food security.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.221-229
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• 2023

Extracted from the metropolitan area, the Paldang Lake, which supplies approximately 8 million tons of water, has achieved a BOD (Biochemical Oxygen Demand) of 1.1 mg/L as a result of water quality preservation policies. However, concerning the COD (Chemical Oxygen Demand) component that encompasses refractory organic matter, there has been an observable upward trend in concentration. The introduction of refractory organic matter into the water source of Paldang Lake brings potential increments in BOD, generates off-putting tastes and odors in tap water, increases THM (Trihalomethane) formation, and triggers algae proliferation. Moreover, if residual hazardous refractory pollutants persist in aquatic environments, they may induce endocrine disruption and phenomena such as antibiotic resistance. In this study, a monitoring campaign was executed to discern the concentration of refractory organic matter emissions from point and non-point sources within Paldang Lake and its upstream region, with the aim of managing refractory organic matter in Paldang Lake. By comparing refractory organic matter emission concentrations across monitored areas, the elimination efficiency at wastewater treatment plants was assessed. Additionally, employing the Pearson correlation correlation analysis technique, correlations among refractory organic matter indices, antecedent wet days, and antecedent dry days were explored. The concentrations of refractory organic matter in rivers and Paldang Lake exhibited a similar pattern. Wastewater treatment plant effluents exhibited higher concentrations compared to rivers and Paldang Lake. The assessment of refractory organic matter removal at wastewater treatment plants indicated a removal efficiency of 65.73%. However, no significant correlation emerged between refractory organic matter emission concentration and antecedent wet days or priory antecedent dry days. This absence of correlation is attributed to data scarcity, underscoring the need for long-term monitoring and data accumulation.

• Journal of Yeungnam Medical Science
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• v.27 no.2
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• pp.113-121
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• 2010

Background and purpose : Patients with acute leukemia experience prolonged periods of neutropenia due to their disease or its treatment. For this reason, they often develop serious infectious complications. Although antibiotic therapy has improved in recent years, the fatality rate from infection remains high. For the control of infection, protected environment was developed. But because of economic issue, most of chemotherapy with acute myeloid leukemia have conducted in non-protected environment. So this study compared the rate of complete remission, days with neutropenia, rate of fever, rate of positive culture, rate of overt infection and use of antibacterial and antifungal agents with patients within non-protected environment and protected environment, retrospectively, Patients with acute myeloid leukemia during first remission induction chemotherapy were eligible for this study, Methods : Retrospective analysis was conducted between patients in non-protected (25 patients) and protected environment (14 patients) with acute myeloid leukemia during remission induction chemotherapy Results : Rate of overt infection, rate of fever, rate of positive culture and rate of use of antibiotics were significantly high in patients within non-protected environment compared with patients within protected environment. There were no differences in rate of complete remission and days of neutropenia Conclusions : This study suggests protected environment for patients with acute myeloid leukemia during remission induction chemotherapy could reduce rate of overt infection, and rate of use of antibiotics.

• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.183-191
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• 2018

The study was conducted to investigate the effect of dietary supplementation of Lactobacillus, medicinal plants extract, and essential oil on laying performance, cecal microflora, relative organic weight, leucocyte profiles in laying hens against Salmonella gallinarum. A total of 100 Hy-Line Brown laying hens of 65 weeks of age were assigned into 5 dietary treatments supplemented with no antibiotic (negative control), antibiotic (positive control), Lactobacillus 0.1% (LB), medicinal plants extract 100 ppm (MPE), herb extract 100 ppm (EO). After 7 days of treatment, the 20 hens in each treatment group were divided into challenge group (n=10) and non-challenge group (n=10) for oral administration of Salmonella gallinarums, and were maintained in the same dietary treatments for two additional weeks. Laying hens were selected 20 by each treatment, splitting up into oral Salmonella group and nontreated group. The feeding trial lasted for one weeks and Salmonella gallinarum was orally administered for two weeks. Egg production, egg weight, egg mass, and feed conversion ratio were calculated and cecal microflora, relative organ, and blood were collected at the end of experiment. Compared with the control, laying hens fed Lactobacillus, medical plant extract, and essential oil were not observed to change of laying performance. Salmonella count increased significantly when Salmonella gallinarum was orally administered (P<0.05) but coliform bacteria and Lactobacillus counts were not affected. The relative organs weight was not different in hens with oral administration of Salmonella gallinarum and also in hens fed Lactobacillus, medical plant extract, and essential oil. H/L ratio was not significantly different, but total leucocyte level was somewhat increased in the treatment with oral administration of Salmonella gallinarum and more leucocyte increased in laying hens fed Lactobacillus, medical plant extract, and essential oil than control.

• Korean Journal of Poultry Science
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• v.33 no.1
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• pp.33-39
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• 2006

This study was conducted to investigate the feeding effect of $bio-silverlite^{(R)}$ on growth performance, organ phenomenon and cecum microflora in broiler chicks. The $bio-silverlite^{(R)}$ was made by an ion exchange between illite and $silver(Ag^+)$. There were four treatment groups: negative control group(non-treatment), antibiotic supplement group (positive control), 0.5% $bio-silverlite^{(R)}$ supplment group and 1.5% $bio-silverlite^{(R)}$ supplement group. Total 200 birds was assigned for this five replication tests, allocating 10 birds into each treatment. Experimental diets were formulated on isocalories and isonitrogen for the whole experimental period. Body weight gain was higher in antibiotic supplementation (+C) and $bio-silverlite^{(R)}$ supplement groups(S 0.5% and 51.5%) than the negative control group(-C), and feed efficiency was significantly enhanced with increase of the level of $bio-silverlite^{(R)}$ supplement. The length of small intestine was longer in +C than in -C and $bio-silverlite^{(R)}$ supplement groups (P<0.05), and the weight of small intestine was proportional to the level of $bio-silverlite^{(R)}$ supplement. Crop weight was lower in $bio-silverlite^{(R)}$ supplement group than in -C and +C groups (P<0.05), and the cecum weight was heavier in $bio-silverlite^{(R)}$ supplementation group. Intestinal villi height was longer in 51.5% group at 3 weeks and 6 weeks of age than in -C and +C groups. With the respect of the formation of intestinal microflora, TBC and CBC was not affected by age and feed additive. However, the number of LAB was slightly higher in $bio-silverlite^{(R)}$ supplement group than in -C and +C groups.

• Korean journal of applied entomology
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• v.24 no.2 s.63
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• pp.51-60
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• 1985

This paper was performed to study the nature of varietal resistance of some Korean-new rice cultivars to the brown planthopper (BPH), Nilaparvata lugens ($ST{\AA}L$). The rice cultivars tested were Cheongcheong, Gaya, Hangangchal, Samgang, Nampoong and Yeongpoong which have been reported as having resistant genes for the BPH. The check varieties were Jinheung, Sangpoong and Chucheong for susceptible and IR-36 for resistant. The factors studied were referred to the seedling responses, preference in feeding and oviposition of BPH, antibiosis (nymphal development, adult emergence and sex ratio, adult body weight, population build-up, feeding amount and amylase activity), and chemical composition (inorganic components, chlorophyll contents, cell wall components, amino acids and esterase isozymes) of leaf- sheath and/or roots of rice plants. In conclusion, the natures of varietal resistance of rice cultivars to the BPH were not only correlated with the resistant reaction of rice plant, but also they were related with the non preference in feeding and oviposition and those resistant cultivars had the antibiotic effects to the insects. Their antibiotic effects of rice cultivars to the BPH would be related with some of the chemical components of rice plants, such as the contents of magnesium oxide (MgO), and chlorophyll and the different esterase isozymes.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.384-397
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• 2018

The aim of this study is to screen the strains of Bacillus spp. possessing safety, probiotic activity, and so on, which can be utilized as probiotic resource for using the feed and supplement food of companion animal. About 300 isolates were isolated from traditional Korean sauces, four isolates that did not have or produce the six kinds of B. cereus type vomiting and diarrhea toxin genes, ${\beta}$-hemolytic, and three kinds of carcinogenic enzymes were selected. Antibiotic gene retention, cell surface hydrophobicity, antibiotic sensitivity, and glucose utilization were analyzed for four isolates, and finally SRCM 100731 was selected. SRCM 100731 was named as Bacillus amyloliquefaciens SRCM 100731 16S rRNA sequencing analysis, and carried out optimization of cell growth for industrial applications such as pet food and feed. The effects of 14 different components on cell growth were investigated and three significant positive factors, molasses, sodium chloride, and potassium chloride were selected as the main factors based on a Plackett-Burman design. In order to find out optimal concentration on each constituent, we carried out central composite design. The predicted optimized concentrations were 7% molasses, 1.1% sodium chloride, 0.5% potassium chloride. Finally, an overall about 7-fold increase in dry cell weight yield ($12.6625{\pm}0.0658g/L$) was achieved using the optimized medium compared with the non-optimized medium ($1.8273{\pm}0.0214g/L$). This research is expected to be highly utilized in the growing pet industry by establishing optimal cultivation conditions for industrial application as well as screening Bacillus amyloliquefaciens SRCM 100731 as probiotic resource for companion animal.

• Journal of Preventive Medicine and Public Health
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• v.33 no.3
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• pp.285-298
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• 2000

Objectives : To investigate the positive rate of Helicobacter pylori in patients with dyspepsia; medical compliance and related factors; the eradication rate a year after screening and related factors; the relationship between the eradication of Helicobacter pylori and the improvement of symptoms; and the estimated cost of three alternative approaches to treat Helicobacter pylori in the community. Methods : A total of 510 subjects with dyspeptic symptoms were selected and given the serological test in March 1998. The subjects were all adults over 30 years of age residing in Kyongju city. Results : Of the 510 selected subjects, 375 (73.5%) subjects proved positive for Helicobacter pylori on serological testing. Of these 304 (81.1%) who consented to an endoscopic examination, underwent a Campylobacter-like organism (CLO) test. Of these 304 subjects, 204 (67.1%), who had positive CLO test results, were given the triple therapy - tripotassium dicitrato bismuthate, amoxicillin, and metronidazole. To determine the eradication rate of Helicobacter pylori, 181 (88.1%) out of the 204 subjects who were given the triple therapy completed a follow-up urea breath test one year later. Of these, the Helicobacter pylori of 87(48.1%) subjects was eradicated. Among the 122 subjects who were medication compliant, the Helicobacter pylori eradication rate was 57.4% (70 subjects), while the eradication rates was only 28.8% (17subjects) in the non-compliant group. The Helicobacter pylori eradication was significantly related to compliance (p<0.01), but not to other characteristics and habits. The symptom improvement rate tended to be higher 62.1%), in the Helicobacter pylori eradicated group than in the non-eradicated group (59.6%). Conclusions : When the advantages and disadvantages of each alternative treatment were considered in the light of cost, antibiotic tolerance and the number of patients to be treated, alternative II was favorable in terms of cost. Alternative III was favorable in terms of the number of patients to be treated, antibiotic tolerance and early detection of gastric cancer. Further long-term research analyzing the cost-benefit and cost-effectiveness of each treatment will be needed as supporting material in creating new policies.