• The Korean Journal of Gastroenterology
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• v.72 no.5
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• pp.237-244
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• 2018

While the prevalence of Helicobacter pylori (H. pylori) infection is decreasing in Korea, the incidence of gastric cancer remains high, emphasizing the importance of H. pylori eradication. A new treatment strategy is needed as the eradication rate with standard triple therapy, which is currently the standard first-line regimen for H. pylori infection, has decreased below the optimum level. The major cause of eradication failure is increased antibiotic resistance. Sequential, concurrent, and hybrid therapies that include clarithromycin produce higher eradication rates than conventional standard triple therapy. However, the effectiveness of these treatments is limited in regions where the resistance rate to various antibiotics is high. Bismuth quadruple therapy is another alternative therapy, but again the eradication rate is not sufficiently high. Tailored therapy based on individual characteristics, including antibiotic susceptibility, may be ideal, but there are several limitations for clinical application and further research is needed. New potassium-competitive acid blocker-based therapies could emerge as effective alternatives in the near future. A consensus is needed to establish a strategy for applying new eradication therapies in Korea.

• Journal of Food Hygiene and Safety
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• v.35 no.2
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• pp.103-108
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• 2020

Recently, consumer demand for safe but minimally processed food has rapidly increased. For this reason, many food processing industries are applying hurdle technology to enhance food safety, extend shelf life, and make foods appear minimally processed. Meanwhile, studies have shown that a treatment (stress) meant to inactivate foodborne pathogens may trigger adaptation mechanisms and could even offer cross protection against subsequent treatments. Also, certain routine farm practices such as antibiotic and herbicide use could result in the development of antibiotic-resistant pathogens. Such bacteria may be tolerant to food processing-associated stress and be more likely to remain viable in processed foods. In this review, we discuss the correlation between food processing-associated stress and antibiotic resistance. We also discuss molecular mechanisms such as the use of sigma factors, SOS response pathways and efflux pumps as means of cross protection against antimicrobial compounds and other food processing-associated stresses.

• Journal of Microbiology and Biotechnology
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• v.33 no.3
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• pp.329-338
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• 2023

Enterohemorrhagic Escherichia coli (EHEC) is a foodborne pathogen that produces attaching and effacing lesions on the large intestine and causes hemorrhagic colitis. It is primarily transmitted through the consumption of contaminated meat or fresh produce. Similar to other bacterial pathogens, antibiotic resistance is of concern for EHEC. Furthermore, since the production of Shiga toxin by this pathogen is enhanced after antibiotic treatment, alternative agents that control EHEC are necessary. This study aimed to discover alternative treatments that target virulence factors and reduce EHEC toxicity. The locus of enterocyte effacement (LEE) is essential for EHEC attachment to host cells and virulence, and most of the LEE genes are positively regulated by the transcriptional regulator, Ler. GrlA protein, a transcriptional activator of ler, is thus a potential target for virulence inhibitors of EHEC. To identify the GrlA inhibitors, an in vivo high-throughput screening (HTS) system consisting of a GrlA-expressing plasmid and a reporter plasmid was constructed. Since the reporter luminescence gene was fused to the ler promoter, the bioluminescence would decrease if inhibitors affected the GrlA. By screening 8,201 compounds from the Korea Chemical Bank, we identified a novel GrlA inhibitor named Grlactin [3-[(2,4-dichlorophenoxy)methyl]-4-(3-methylbut-2-en-1-yl)-4,5-dihydro-1,2,4-oxadiazol-5-one], which suppresses the expression of LEE genes. Grlactin significantly diminished the adhesion of EHEC strain EDL933 to human epithelial cells without inhibiting bacterial growth. These findings suggest that the developed screening system was effective at identifying GrlA inhibitors, and Grlactin has potential for use as a novel anti-adhesion agent for EHEC while reducing the incidence of resistance.

• Journal of Oral Medicine and Pain
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• v.47 no.1
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• pp.52-61
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• 2022

Purpose: Most cases of oral and maxillofacial infections are usually easily treated by proper diagnosis, elimination of causative factors, and antibiotic therapy. However, the emergence and the increase of multidrug-resistant bacteria make treatment challenging. "ESKAPE" pathogens are the most common opportunistic organisms in nosocomial infections and have resistant to commonly used antibiotics. There are many medical reviews of ESKAPE pathogens, but few in dentistry. This study focuses on oral and maxillofacial infection especially with ESKAPE pathogens. The purpose of this study is to prepare feasible data about tracing and treatment of infection related to pathogens that may be beneficial to clinicians. Methods: A total of 154 patients with oral and maxillofacial infections were reviewed by analyzing retrospectively hospitalized data in the Department of Oral and Maxillofacial surgery, Chosun University Hospital, Korea, past 5 years from January 2014 to December 2018. Based on the medical records and microbiological tests, the results were divided into two groups: infections with ESKAPE pathogens and other bacteria. Results: A total of 22 species were isolated from 154 patients. The proportion of ESKAPE pathogens among all bacterial isolates collected from infected patients was 39.6%. Causative factors, especially in post-operative infection, showed a statistically significant correlation to ESKAPE infections (29 cases). And average of treatment period in ESKAPE group was longer than non-ESKAPE groups. Overall, Klebsiella pneumoniae (60.7%) was the most frequently isolated ESKAPE pathogen. And high antibiotic resistance rates had been detected in the ESKAPE during the five-year period. Conclusions: Infections with ESKAPE pathogens are now a problem that can no longer be overlooked in Dentistry. Based on results of this study, ESKAPE pathogens were highly associated with post-operative or opportunistic infections. Clinicians should be careful about these antibiotic resistant pathogens and use appropriate antibiotics to patients while having dental treatments.

• Korean Journal of Poultry Science
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• v.44 no.2
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• pp.113-122
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• 2017

This study was conducted to investigate the effect of dietary supplementation with Lactobacillus, medicinal plant extracts, and plant extracts on growth performance, cecal microflora, relative organ weight, and lymphocyte profile in broiler chickens. One hundred broilers (5 wk old) were used and divided into five (treatment) ${\times}$ two (challenged Salmonella) groups containing 10 broilers. The treatments were as follows: no antibiotics group (NC), antibiotics group (PC), 0.1% lactic acid bacteria group (LB), 100 ppm medicinal plant extract group (MPE), and 100 ppm herb extract group (HE). A basal diet was formulated as 3,100 kcal/kg ME and 20% CP based on corn and soybean meal. Broilers were fed with the experimental diets with no challenge for 1 wk and with challenge of SG for 2 wk. SG were added in water as $1.0{\times}10^6cfu/L$. Final body weight and weight gain were significantly decreased following challenge with SG (P<0.05). However, with the addition of antibiotic alternatives, growth performance was improved and reduction of performance following challenge with SG was lowed compared with that of the NC treatment (P<0.05). Coliform bacteria and Salmonella but not lactic acid bacteria increased with the addition of antibiotic alternatives (P<0.05). Lactobacillus increased significantly with the addition of lactic acid bacteria compared with the NC and PC treatments (P<0.05). The weight of liver, spleen, and bursa of Fabricius increased with addition of antibiotic alternatives (P<0.05). WBC was highly reduced at 4 days after challenge with SG, but was normally maintained thereafter. There was no significant difference in coliform bacteria, Salmonella, organ weights, or WBC with the addition of antibiotic alternatives. Finally, Lactobacillus, medicinal plant extract, and herb extract can be used as antibiotic alternatives; but one alternative completely can't alternate as antibiotics. Therefore, further studies are needed to investigate the synergistic effects of two or more antibiotic alternatives.

• Journal of Animal Science and Technology
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• v.45 no.4
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• pp.537-542
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• 2003

Sixty [(Duroc${\times}$Yorkshire)${\times}$Landrace] pigs (7.63$\pm$0.41kg average body weight and 25-d average age) were used in a 20-d growth assay to determine the effect of dietary recombinant human lactoferricin culture (RHLC) supplementation on growth performance, digestibility and plasma IgG concentration in weaning pigs. Dietary treatments included 1) Negative control (NC : without antibiotic), 2) Positive control (PC : NC diet + 0.1% chlortetracycline), 3) RHLC0.3 (NC diet + 0.3% RHLC), 4) RHLC0.5 (NC diet + 0.5% RHLC). No differences were found among treatments in average daily gain (P>0.05). ADFI of pigs fed RHLC0.3 diet was higher than that of pigs fed PC diet (P<0.05). However, pigs fed RHLC0.5 diet had improved gain/feed compared to pigs fed PC diet. Pigs fed PC and RHLC diets showed significantly increased dry matter digestibility compared to pigs fed NC diet (P<0.05). There was no significant difference in plasma IgG concentrations (P>0.05). The supplementation of RHLC in starter pig diets appears to be an alternative to antibiotics.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.8-14
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• 2001

To investigate the effects of waste sludge from antibiotic fermentation on the growth of young radish and chemical properties of soil, five levels of fertilizer, control (recommended fertilizer, $N-P_2O_5-K_2O=160-59-104$ kg/ha), AS(control + sludge 1,000 kg/ha), AC(control + conventional compost 1,000 kg/ha), SNS(control - subtracting 30% N of sludge + sludge 1,000 kg/ha) and SNC(control - subtracting 30% N of conventional compost + conventional compost 1,000 kg/ha) were applied and radish was grown twice with same treatments on May and August in 1998. Germination rate and early growth of young radish grown with AS and SNS were lower than those grown in control and with AC, SNC. This negative effects by adding the sludge in the early growth seemed to be caused by damage of ammonia gas released during degradation of the sludge in soil. However, yield of young radish showed no significant difference among all the treatments including the AS and SNS at the 1st and 2nd experiment, and these suggested that the latter half of growth of young radish was accelerated by adding the sludge. Contents of T-N in young radish and inorganic N in soil showed a tendency to increase by adding the sludge while antibiotic substance, cephalosporin-C, was not detected in plant material and soils after harvest of young radish in both experiments. Consequently, waste sludge from antibiotic fermentation, which contains high levels of organic matter and nitrogen could be used as an useful resource in agriculture.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.10
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• pp.1451-1456
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• 2012

A total of 144 ((Duroc${\times}$Yorkshire)${\times}$Landrace)) pigs with an average initial BW of $28.85{\pm}0.63$ kg were used in this 6-wk growth trial. Pigs were randomly allotted to 1 of 4 treatments in a completely random block design. Each dietary treatment consisted of 9 replicate pens, with 4 pigs per replicate. Dietary treatments included: i) NC (basal diet), ii) PC (NC+apramycin 0.5 g/kg), iii) BPT1 (NC+bacteriophage 0.25 g/kg) and iv) BPT2 (NC+bacteriophage 0.5 g/kg). The inclusion of antibiotics and bacteriophages did not affect the (p>0.05) ADG, ADFI and G:F compared with the basal diet. Dietary antibiotics and bacteriophages supplementation led to a higher (p<0.05) DM digestibility than the NC treatment. Pigs fed the bacteriophage supplemented diet increased (p<0.05) the N digestibility compared with those fed NC treatment. Supplementation of antibiotics led to a higher (p<0.05) energy digestibility than the NC treatment. No difference (p>0.05) was observed in the RBC, WBC, lymphocyte concentration and fecal moisture among treatments. Pigs fed PC and BPT2 treatments reduced (p<0.05) the E. coli concentration compared with those fed NC treatment. The inclusion of BPT2 treatment led to a higher (p<0.05) lactobacillus concentration compared with NC and PC treatment. Dietary antibiotic and bacteriophage supplementation reduced (p<0.05) the Salmonella concentration compared with NC treatment. In conclusion, our study suggested that bacteriophage at the level of 0.5 g/kg could be used as an antibiotics alternative for growing pigs.

• Journal of agriculture & life science
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• v.46 no.4
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• pp.119-127
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• 2012

To investigate the influence of multi-probiotic, fermented ginseng byproduct and fermented sulfone on the performance, intestinal microflora and immunity of broiler, a five weeks trial was conducted with 340, 1-d-old $Ross{\times}Ross$ broiler. All broilers were divided into five different groups having 68 birds in each treatment, and they were assigned as control, antibiotic avilamycin (AB), multi-probiotic (MP), fermented sulfone (FS) and fermented ginseng byproduct (FGB). Each artificial or naturally derived probiotic was inoculated 0.1% level with the basal diet, and all diets were provided to birds for five weeks. Weight gain and feed intake were measured weekly basis, and blood, spleen and feces were collectedand used for the physiological properties of broiler chickens. All performances and cholesterol profiles were not significantly differed but numerically lower level of neutral fat and LDL was found in multi-probiotics and FGB treatments respectively. The salmonella spp and E. coli numbers in the ileum were high in control in relation to those of other treatments and were significantly decreased in antibiotics treatments (p<0.05). In addition, Lactobacillus spp. showed significantly higher proliferation in MP as compared to that of others (p<0.05). Fecal ammonia and $CO_2$ gas emission was significantly decreased in MP, FGB and FS, respectively (p<0.05), but significantly increased proliferation of spleen was determined in MP group in comparison of other treatments (p<0.05). Therefore, the results indicates that multi-probiotics would be valuable feed additives to improve the salmonella, E. coli and Lactobacillus proliferation, and manure gas emission of broiler chickens, but further study related to the production of manure gas emission of MP is necessary.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.8
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• pp.1202-1208
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• 2009

Synbiotics is the term used for a mixture of probiotics (live microbial feed additives that beneficially affects the host animal) and prebiotics (non-digestible food ingredients that beneficially affect the organism). This study investigated the effect of probiotics from anaerobic microflora with prebiotics on growth performance, nutrient digestibility, noxious gas emission and fecal microbial population in weaning pigs. 150 pigs with an initial BW of 6.80${\pm}$0.32 kg (20 d of age) were randomly assigned to 5 dietary treatments as follows: i) US, basal diet+0.15% antibiotics (0.05% oxytetracycline 200 and 0.10% tiamulin 38 g), ii) BS, basal diet+0.2% synbiotics (probiotics from bacteria), iii) YS, basal diet+0.2% synbiotics (probiotics from yeast), iv) MS, basal diet+0.2% synbiotics (probiotics from mold), v) CS, basal diet+0.2% synbiotics (from compounds of bacteria, yeast and mold). The probiotics were contained in $10^{9}$ cfu/ml, $10^{5}$ cfu/ml and $10^{3}$ tfu/ml of bacteria, yeast and molds, respectively. The same prebiotics (mannan oligosaccharide, lactose, sodium acetate and ammonium citrate) was used for all the synbiotics. Pigs were housed individually for a 16-day experimental period. Growth performance showed no significant difference between antibiotic treatments and synbiotics-added treatments. The BS treatment showed higher (p<0.05) dry matter (DM) and nitrogen digestibility while ether extract and crude fiber digestibility were not affected by the dietary treatment. Also, the BS treatment decreased (p<0.05) fecal ammonia and amine gas emissions. Hydrogen sulfide concentration was also decreased (p<0.05) in BS, YS and MS treatments compared to other treatments. Moreover, all the synbioticsadded treatments increased fecal acetic acid concentration while the CS treatment had lower propionic acid concentration than the US treatment (p<0.05) gas emissions but decreased in fecal propionate gas emissions. Total fecal bacteria and Escherichia coli populations did not differ significantly among the treatments, while the Shigella counts were decreased (p<0.05) in synbiotics-included treatment. Fecal bacteria population was higher in the YS treatment than other treatments (p<0.05). The BS treatment had higher yeast concentration than YS, MS and CS treatments, while US treatment had higher mold concentrations than MS treatment (p<0.05). Therefore, the results of the present study suggest that synbiotics are as effective as antibiotics on growth performance, nutrient digestibility and fecal microflora composition in weaning pigs. Additionally, synbiotics from anaerobic microflora can decrease fecal noxious gas emission and synbiotics can substitute for antibiotics in weaning pigs.