• Natural Product Sciences
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• v.24 no.4
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• pp.225-228
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• 2018

By activity-guided fractionation, gliotoxin was isolated as an antibacterial metabolite of the fungus Penicillium decumbens which was derived from the jellyfish Nemopilema nomurai. Gliotoxin was further evaluated for antibacterial activity against several piscine and human MDR (multidrug resistance) pathogens. Gliotoxin showed significant antibacterial activity against Gram-positive piscine pathogens such as Streptococcus iniae FP5228, Streptococcus iniae FP3187, Streptococcus parauberis FP3287, Streptococcus parauberis SPOF3K, S. parauberis KSP28, and Lactococcus garvieae FP5245. Gliotoxin showed strong activity especially against S. parauberis SPOF3K and S. iniae FP5228, which are resistant to oxytetracycline. It is noteworthy that gliotoxin effectively suppressed streptococci which are the major pathogens for piscine infection and mortality in aquaculture industry. Gliotoxin also showed strong antibacterial activity against multidrug- resistant human pathogens (MDR) including Enterococcus faecium 5270 and MRSA (methicillin-resistant Staphylococcus aureus) 3089.

• Journal of Korean Foot and Ankle Society
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• v.13 no.2
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• pp.146-149
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• 2009

Purpose: Foot infections are common complications in patients with diabetes. The patients are usually immune-compromised; therefore the pathogens could be resistant to narrow spectrum antibiotics. Those drugs, however, are categorized as specially managed antibiotics, and access are difficult without confirming of the pathogens. Our aim was to analyze the common pathogens in diabetic foot infection and figure out the proper antibiotics. Materials and Methods: We studied 68 patients treated with diabetic foot infection. The pathogens which caused the infection and their sensitivity to initial antibiotics were analyzed. We also investigated the change of the antibiotics after the confirming of the culture result and average time to get the result. Results: Among the 68 patients, 56 (82%) received cephalosporin and beta-lactam antibiotics. Only 12 (18%) who were confirmed the drug resistant pathogens from previous culture, were treated with broad spectrum antibiotics such as vancomycin and tazoperan. Average culture study time was 6 days. Methicillin-resistant staphylococcus aureus (MRSA) was cultured in 19 patients (28%), Methicillin-resistant coagulase negative staphylococcus (MRCNS) in 11 patietns (17%), pseudomonas in 11 patients (17%). Total 44 (65%) including 3 of other antibiotics resistant pathogen needed broad spectrum antibiotics. Thirty two patients (47%) were resistant to initial antibiotics.irt follow up culture, 2 MRSA and 2 MRCNS were found. The antibiotics resistant pathogens were confirmed in 48 (71%) patients at last. Conclusion: Diabetic patients with foot infection need proper antibiotics from initial treatment. The proper broad spectrum antibiotics should assigned to the patients from the first time without the confirming of the culture results.

• 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.

• Journal of Environmental Health Sciences
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• v.38 no.5
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• pp.415-423
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• 2012

Objectives: This study was performed in order to evaluate antibiotic resistance and analyze the multiple antibiotic resistance of food-borne pathogens isolated from indoor air and an air cleaner at a lunch room in a child care center. Methods: An antibiotic test of food-borne pathogens, including four Staphylococcus aureus and 23 Bacillus cereus was conducted through the disk diffusion method from Clinical and Laboratory Standard Institute. Results: All Staph. aureus was resistant to Ampicillin and Penicillin, while B. cereus was also resistant to Ampicillin, Cefepime and Penicillin. All isolates showed Vancomycin susceptibility but three out of four Staph. aureus and all B. cereus were resistant to Oxacillin. Staph. aureus and B. cereus presented two or more multiple antibiotic resistances. Conclusions: The results indicated that food-borne pathogens isolated from indoor air and an air cleaner at a lunch room in a child care center showed multiple antibiotic resistances. The repeated control of indoor environment quality is required and continuous surveillance of antibiotic resistant strains is demanded.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.5
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• pp.659-664
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• 2010

The present study was to investigate the effect of the transition from conventional to organic dairy farming on the antimicrobial resistant pattern of pathogens in milk. A farm with tie-stall management, with an average herd size of 20 milking cows, was selected based on the owner' willingness to accept, for at least 6 months, the highly restricted protocol developed in this study. Comparisons of bacterial isolates and antimicrobial susceptibilities before changing to an organic farm system (BEFORE) and for 6 months after (AFTER) operating the experimental organic farm system were performed by Fisher's Exact Chi-square tests. Significant levels were defined at p<0.05. During the AFTER period, average frequency of antibiotic treatment was decreased from more than 3 cases/month to less than 1 case/month during which the antibiotic use was authorized only by the veterinarian. In total, 92 and 70 quarter milk samples from 24 and 18 cows during BEFORE and AFTER, respectively, were included in the study. Overall, isolates ranged from a non-resistant level for cephazolin to a very high resistant level to streptomycin (64.71% to 95.45%). Percentages of antimicrobial resistant isolates during BEFORE were significantly higher than during AFTER for ampicillin (43.48% and 5.88%, respectively) and streptomycin (95.45% and 64.71%, respectively). In conclusion, percentages of antimicrobial resistant isolates were decreased after 6 months of operating as an organic farm system.

• Journal of Veterinary Clinics
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• v.21 no.2
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• pp.133-139
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• 2004

Bacterial pathogens were isolated from 36 dogs with respiratory signs, that were submitted to Veterinary Clinics in Jeju, including Veterinary Medical Teaching Hospital in Cheju National University. Of 36 isolates, 16 (44.4%) bacterial pathogens were Gram-positive and 20 (55.6%) were Gram-negative. Gram-positive bacteria identified with API Staph were 12 S. intermedius (33.3%), 2 S. aureus (5.6%), 1 S. haemolyticum (2.8%), and 1 S. xylosus (2.8%). Gram-negative organisms identified with API 20E or API NE included 8 Bordetella bronchiseptica (22.2%), 6 Escherichia coli (16.7%), 4 Pasteurella spp. (11.1%), 1 Enterobacter intermedius (2.8%), and 1 Oligella ureolytica (2.8%). Both Staphylococcus spp. isolates and Gram-negative pathogens were resistant to one or more antibiotics, including ampicillin (AM), amoxicillin/clavulanic acid (AMC), chloramphenicol (C), cefazolin (CZ), erythromycin (E), gentamicin (GM), kanamycin (K), lincomycin (L), oxacillin (OX), trimethoprim/sulfamethoxazole (SXT), and tetracycline (TE). All Staphylococcus spp. were susceptible to AMC, OX and VA, while many isolates were highly resistant to L (87.5%), E (68.8%), P (62.5%), and AM (56.3%). Antibiotic-resistant patterns of staphylococcal isolates were shown ranges from single to 9-resistant patterns. Resistant rates to antibiotics of Gram-negative bacteria were usually higher than those of Staphylococcus spp. in this study. Most Gram-negative bacteria were highly resistant to L (90.0%), AM (85.0%), E (85.0%), P (85.0%), OX (80.0%), and CZ (75.0%). B. bronchiseptica isolates showed 5 to 8 antibiotics-resistant patterns and Pasteurella spp., 2 to 8-resistant patterns. In particular, all 6 E. coli isolates were resistant to more than 9 different kinds of antibiotics, including one strain resistant to all antibiotics tested.

• The Plant Pathology Journal
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• v.38 no.1
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• pp.25-32
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• 2022

Plant pathogens pose major threats on agriculture and horticulture, causing significant economic loss worldwide. Due to the continuous and excessive use of synthetic pesticides, emergence of pesticide resistant pathogens has become more frequent. Thus, there is a growing needs for environmentally-friendly and selective antimicrobial agents with a novel mode of action, which may be used in combination with conventional pesticides to delay development of pesticide resistance. In this study, we evaluated the potentials of lichen substances as novel biopesticides against eight bacterial and twelve fungal plant pathogens that have historically caused significant phytopathological problems in South Korea. Eight lichen substances of diverse chemical origins were extracted from axenic culture or dried specimen, and further purified for comparative analysis of their antimicrobial properties. Usnic acid and vulpinic acid exhibited strong antibacterial activities against Clavibacter michiganensis subsp. michiganensis. In addition, usnic acid and vulpinic acid were highly effective in the growth inhibition of fungal pathogens, such as Diaporthe eres, D. actinidiae, and Sclerotinia sclerotiorum. Intriguingly, the growth of Rhizoctonia solani was specifically inhibited by lecanoric acid, indicating that lichen substances exhibit some degrees of selectivity to plant pathogens. These results suggested that lichen substance can be used as a selective biopesticide for controlling plant disease of agricultural and horticultural significance, minimizing possible emergence of pesticide resistant pathogens in fields.

• Natural Product Sciences
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• v.23 no.4
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• pp.286-290
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• 2017

Multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa are highly dangerous nosocomial pathogens, cause the symptoms of skin infections, pressure sores, sepsis, blood stream and wound infections. Unfortunately, these pathogens are immune to the most common antibiotics, such as, carbapenem, aminoglycoside and fluoroquinolone. Therefore, it is imperative that new and effective antibiotics be developed. In the present study, the antimicrobial effects of Aloe vera MAP (modified Aloe polysaccharide) on Staphylococcus aureus and Bacillus subtilis, Escherichia coli and Enterobacter aerogenes, and clinical Pseudomonas aeruginosa and clinical Acinetobacter baumannii were comprehensibly investigated. Prior to the growth inhibition effect measurement and antibiotic disc diffusion assay on gram-positive and gram-negative bacteria and selected multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii, antimicrobial resistance screening was performed for the multidrug-resistant bacteria obtained from clinical isolates. The results for showed the Aloe vera MAP had a concentration-dependent effect on all of examined bacteria, particularly on Pseudomonas aeruginosa. Anti-inflammatory and anti-oxidant experiments were also performed dose dependently effects to confirm the beneficial physiological effects of Aloe vera MAP.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.816-823
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• 2022

The rapid spread of superbugs leads to the escalation of infectious diseases, which threatens public health. Endolysins derived from bacteriophages are spotlighted as promising alternative antibiotics against multi-drug resistant bacteria. In this study, we isolated and characterized the novel Salmonella typhimurium phage PBST08. Bioinformatics analysis of the PBST08 genome revealed putative endolysin ST01 with a lysozyme-like domain. Since the lytic activity of the purified ST01 was minor, probably owing to the outer membrane, which blocks accessibility to peptidoglycan, antimicrobial peptide cecropin A (CecA) was fused to the N-terminus of ST01 to disrupt the outer membrane. The resulting CecA::ST01 has been shown to have increased bactericidal activity against gram-negative pathogens including Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, Escherichia coli, and Enterobacter cloacae and the most affected target was A. baumannii. In the presence of 0.25 µM CecA::ST01, A. baumannii ATCC 17978 strain was completely killed and CCARM 12026 strain was wiped out by 0.5 µM CecA::ST01, which is a clinical isolate of A. baumannii and resistant to multiple drugs including carbapenem. Moreover, the larvae of Galleria mellonella could be rescued up to 58% or 49% by the administration of CecA::ST01 upon infection by A. baumannii 17978 or CCARM 12026 strain. Finally, the antibacterial activity of CecA::ST01 was verified using 31 strains of five gram-negative pathogens by evaluation of minimal inhibitory concentration. Thus, the results indicate that a fusion of antimicrobial peptide to endolysin can enhance antibacterial activity and the spectrum of endolysin where multi-drug resistant gram-negative pathogens can be efficiently controlled.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.68.1-68
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• 2003

When plants are infected by plant pathogens, typical disease symptom termed lesion, appears in compatible interaction. Whereas, in incompatible interactions, only small speck of lesions are visible on the leaf surfaces. Hypersensitive response (HR) of plant which is the result of infection by incompatible pathogens, is a well known defense response inducing rapid cell death resulting in complete resistance. However, some rice mutants show spontaneous disease symptoms during the growth stages without interaction with pathogens. We investigated the spontaneous cell death mutant called Blast Lesion Mimic(BLM) generated by EMS mutation, on the relationship with the hypersensitive response as well as resistant characteristics. Accumulation of phenolic compounds were detected around the lesions as lesions develop on leaf surface. Activation of PR gene was detected before the lesion appeared, and that result indicates the defense-related response are started earlier than lesion formation. The BLM mutant showed resistant response to inoculation of Magnaporthe grisea KJ201 with which the wild type Hwacheong is totally susceptible. Informations on the formation of spontaneous lesions and detail analysis of lesion mimic mutants and related genes are very limited to date. It is really important to understand the phenomenon of the defense-related lesion formation for developing resistant cultivar for rice blast pathogens