• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.6
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• pp.800-806
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• 2016

In total, 151 Escherichia coli isolates from Ruditapes philippinarum in Gomso Bay were analyzed for their susceptibility to 18 different antimicrobial agents and for genes associated with virulence. For virulence genes, each strain of the isolates was positive for the enterotoxigenic E. coli (ETEC)-specific heat-stable toxin (estA), enteroinvasive E. coli (EIEC)-specific invasion-associated locus (iaa) gene and enteropathogenic E. coli (EPEC)-specific attaching and effacing (eae) gene. According to a disk diffusion susceptibility test, resistance to ampicillin was most prevalent (23.2%), followed by resistance to amoxicillin (22.5%), ticarcillin (20.5%), tetracycline (18.5%), nalidixic acid (12.6%), ciprofloxacin (10.6%), streptomycin (9.9%), and chloramphenicol (6.6%). More than 35.8% of the isolates were resistant to at least one antimicrobial agent, and 19.9% were resistant to four or more classes of antimicrobials; these were consequently defined as multidrug resistant. Minimum inhibitory concentration (MIC) ranges for the antimicrobial resistance of the 15 different antimicrobial agents of 54 E. coli strains were confirmed by varying the concentrations from $32-2,048{\mu}g/mL$. Overall, these results not only provide novel insights into the necessity for seawater and R. philippinarum sanitation in Gomso Bay but they also help to reduce the risk of contamination by antimicrobial-resistant bacteria.

• YAKHAK HOEJI
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• v.34 no.1
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• pp.54-63
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• 1990

These studies were made to assess the present stage of resistance of Shigella species to antibiotics and to find characteristics of R-plasmid of these bacteria. From 1986 to 1988, 125 strains of Shigella species were isolated from patients specimens collected in Chung Cheong-do Hospital, Kyunghee Medical Center, city an provincial health & environmental institutes. These specimens were tested for resistance to 12 kinds of antimicrobial agents by agar dilution method. Using Muller-Hinton agar for the assay of drug resistance and Trypticane Soy Broth as propagating medium for conjugation. All the strains (100%) were resistant to one or more antibiotics. Drug resistance patterns of isolated strains were found as the highest resistance to ampicillin (98%) in 1986, to tetracycline (98%) in 1987, to tetracycline (100%) in 1988, all strains were sensitive to gentamicin, amikacin, tobramycin. Chronologically, resistance decreased gradually as it was shown in relation to kanamycin, rifampicin in 1986, 1987 and 1988, (4%, 2%) (4%, 2%) (0%, 0%) respectively. But, resistance was increased year by year as it was shown in relation to tetracycline, nalidixic acid, streptomycin in 1986, 1987, 1988 (89%, 19%, 45%) (98%, 46%, 71%) and (100%, 58%, 88%). The resistance in correlation to more than 5 drugs, which was 13 strains among 47 strains in 1986, 38 strains among 87 strains in 1987, 23 strains among 26 strains in 1988, was increased gradually. In the transfer test of drug resistance by conjugation methods, the rate which was 3 strains (50%) in 1986, 8 strains (62%) in 1987, 3 strains (100%) in 1988, was increased gradually. When the donor strains were conjugated with the recipient strains, the conjugation rate was high in the multiple resistant strains. The relationships of transferring patterns of drug resistance and molecular weight of R-plasmid were variable. However, only a plasmid which has more than 35 Mgd was transferred.

• Korean Journal of Veterinary Service
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• v.34 no.4
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• pp.353-359
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• 2011

Fowl cholera is a contagious acute and chronic disease caused by Pasteurella multocida in both domesticated and wild birds. Acute fowl cholera in both chickens and wild birds has recently been documented in Korea, but the chronic form has not been reported in Korea until now. This study describes the first outbreak of chronic fowl cholera in 13-week-old Arbor Acre broiler breeder chickens submitted to the College of Veterinary Medicine, Kyungpook National University in April 2006. The clinical signs of the affected flock of 9,621 chickens were lameness caused by swollen hock joints, diarrhea, ruffled feathers, and an average weekly mortality of 1.0%. At necropsy, purulent or caseous exudates were found in the hock and wing joints, humerus, and eyes, and severe pneumonia and pericarditis were discovered. Eleven bacterial isolates obtained from the liver, joint, infraorbital sinus and sternal bursa of the submitted chickens were all identified as Pasteurella multocida based on their physiological and biochemical characteristics. Five isolates were examined for antimicrobial susceptibility against 21 different antimicrobial agents including ampicillin. All were resistant to kanamycin, neomycin, and streptomycin, and some were resistant to gentamicin. The tested isolates were all susceptible to the other 17 antimicrobial agents. All 11 isolates were capsular serogroup A based on multiplex polymerase chain reaction. In addition, two of five isolates used in the antimicrobial susceptibility test were identified as somatic serotype 1 by an agar gel diffusion precipitin test, while the others were non-typable.

• Korean Journal of Veterinary Service
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• v.34 no.3
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• pp.217-226
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• 2011

Salmonella spp. is of increasing public health concern as causative pathogens of food poisoning. The aim of this study was to investigate the serotypes and antimicrobial resistance pattern of Salmonella spp. isolated from duck farms in Daegu-Gyeongbuk province. Also, S. Enteritidis and S. Typhimurium isolates were further examined for plasmid analysis, phage typing and pulsed-field gel electrophoresis (PFGE). A total of 34 Salmonella spp. (16.4%) were isolated from duck farms and ten serotypes were identified. The predominant serotypes were S. Typhimurium (23.5%) S. Fyris (17.6%) and S. Haardt (11.8%), S. Agona and S. Enteritidis (respectively 8.8%). Of 34 Salmonella isolates, 15 (44.1%) isolates were resistant to at least one antimicrobial agent and multiple resistance (resistance to more than 4 drugs) was observed in 9 strains (26.5%). The high resistance was found to streptomycin (32.4%), tetracycline (29.4%), ampicillin, kanamycin and nalidixic acid (respectively, 26.5%), all Salmonella isolates were susceptible to cefoxitin, cefotaxime, gentamicin, amikacin and ciprofloxacin. All S. Enteritidis and S. Typhimurium isolates were found to contain only one plasmid (ca. 54 or 55kb, respectively). Among the S. Enteritidis isolates, two phage types were found, PT32a and PT1c, respectively, one isolates did not react with any of the phages used. Whereas, all S. Typhimurium isolates were RDNC (reacts but does not conform). PFGE showed to be a useful typing method better than plasmid analysis and phage typing for discrimination of isolates especially, S. Typhimurium isolates. Our results indicated that the serotypes of Salmonella isolates are widely distributed in duck farms, further epidemiological studies should be carried out.

• Korean Journal of Veterinary Service
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• v.37 no.4
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• pp.233-240
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• 2014

Salmonella spp. are one of the most common bacteria that causes heavy losses in swine industry and have implications for public health. In this study, the correlation between Salmonella seroprev-alence on farms and the isolation rate from slaughtered pigs was analyzed and the antimicrobial resistance of the isolated Salmonella spp. was investigated. A total of 3,001 serum samples for ELISA were collected from 17 farms during two consecutive years (2012-2013). The mean values of ELISA OD% for each 8 age groups were as follows; gilt 27.83 (n=472), sow 23.75 (n=367), 150 days (d) of pig 16.53 (n=278), 130 d 11.87 (n=366), 100 d 9.46 (n=378), 20 d 9.17 (n=394), 70 d 6.56 (n=382), 40 d 3.72 (n=364). From July 2013 to January 2014, a total of 53 (8.0%) Salmonella strains were isolated from 665 slaughtered pigs shipped from those 17 farms. The mean values of ELISA OD% for each age groups serum samples that were collected in the second half of 2013 showed a positive correlation at 100 d (0.61, P<0.05), 130 d (0.45, P<0.1) with the isolation rate of Salmonella spp. in the slaughtered pigs. All the isolates were identified by a real-time PCR and tested for antimicrobial susceptibility. As a result, the predominant serovar was S. Typhimurium (52.8%) and there were 15 strains showing their own antimicrobial resistance pattern. All strains were susceptible to amoxicillin, cefepime, ciprofloxacin and some of them were resistant to streptomycin and tetracycline (60%), ampicillin (53.3%), chloramphenicol (33.3%), respectively.

• Korean Journal of Veterinary Service
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• v.36 no.2
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• pp.73-78
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• 2013

This study was conducted to investigate antibiotic resistance among Salmonella Typhimurium isolates from diseased pigs in Gyeongbuk province during the period 1998~2011. One hundred forty one isolates were tested for antibiotic resistance using the standard disk diffusion method and were examined for presence of resistance gene by PCR method. S. Typhimurium showed high drug resistance rates to tetracycline (95.7%), streptomycin (93.6%), ampicillin (86.5%), cephalothin (80.1%), gentamicin (79.4%), and trimethoprim/sulfamethoxazole (72.3%). Resistance gene, blaTEM, blaPSE1, tetA, tetB, tetG, sul1, sul2, aadA, strA, grm, and temA were detected among the antibiotic resistance isolates and temB, tetC, aadB gene were not detected. One hundred twenty one (89.6%) tetA, two (1.5%) tetB and one (0.7%) tetG gene were detected in the 135 tetracycline resistant isolates. Two (1.6%) temA gene were detected in one hundred twenty two ampicillin resistance isolates and temB was not detected.

• Korean Journal of Microbiology
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• v.5 no.2
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• pp.97-101
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• 1967

Up to the present time, there are only three methods by which we can obtain bacteria free crown gall tissue. According to some papers related to this field, the first method is based on the works of Braun(53') who maintained infected plants at 46-47'c for several days. But the method has a problem that very few plants can tolerate this temperature. The second method is based on the well known observation that old tumors appear to be bacteria free at least 1 or 2% of the explants. Also this method is known to us as laborious and time consuming. The third method is the one we were using that was attempting to kill the bacteria with bacteriacidal agent such as Antibiotics. In fact., it is reported that almost complete control of crown gall of tomato was obtained by Blanchard('51) when plants were grown in a nutrient containing Aureomycin(20${\mu}g$/ml) following needle puncture with the gall bacteria. We have been engaged in making the experiment by applying solution of Penicillin, Streptomycin and of Chloramphenicol(Succinate free) to find the strong bacteriacidal agent through the method of disc plate, and to confirm the effect of antimicrobial action through the method of plant tissue culture system without possible injury to the host plant. The result of this report is the fact the strongest bacteriacidal agent among the above three Antibiotics was Chloramphenicol(Succinate free 1000 p.p.m). and that there happened no injury to the tissue cultures in a White's 10X media containing 1000 p.p.m. of Chloramphenicol.

• Journal of Embryo Transfer
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• v.28 no.4
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• pp.337-342
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• 2013

Salmonellosis is one of the life-threating diseases of goat in Bangladesh. Therefore, the present study was designed to study the prevalence of Salmonellosis, and isolation and characterizations of the Salmonella spp. from apparently healthy and diarrheic goat. A total of 47 faces samples were collected from selected place and cultured onto different prescribed medium to isolate it. In this study, 12.76% (6/47) samples were found to be positive for Salmonella spp. During culture on SS agar medium, all of the Salmonella isolates produced round, smooth, opaque, translucent and black color colonies on SS agar media. All of the isolated Salmonella spp. fermented dextrose, maltose and mannitol with production of acid and gas but did not ferment sucrose and lactose. However, these isolates had showed Indole and Voges-Proskauer test negative, Methyl-Red test positive. All of these isolates were subjected to rapid plate agglutination test with polyvalent "O" (Poly 'O') and polyvalent "H" (poly 'H') antisera where positive agglutination were observed. They were highly sensitive to ciprofloxacin, spiramycin and gentamycin; moderately sensitive to oxytetracyline, streptomycin and amoxicillin; less sensitive to sulphamethoxazole and resistant to penicillin-G. Based on the present findings, it may be concluded that the investigated Salmonella spp. from goats might be S. typhimurium, S. enteritidis, S. brandenburg, S. salford, S. newbrunswick, S. newport or S. dublin. Further study will be needed, therefore it requires further characterization using other serological and molecular techniques.

• Journal of Dairy Science and Biotechnology
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• v.29 no.2
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• pp.81-85
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• 2011

Recently, antimicrobial resistance of microorganisms has been a major concern of its relation to food safety and national health, therefore, customer's needs to organic animal food is still increasing. In this study, we reviewed the usage of antimicrobials in animal farms and antimicrobial resistance of microorganisms isolated from organic dairy farm environments. The isolates from dairy farms were Acinetobacter sp., A. lwoffi, A. johnsonii, A. towneri, Aerococcus viridans, Aeromonas media, A. veronii, Bacillus pseudofirmus, B. pumilus, B. licheniformis, Corynebacterium glutamicum, Escherichia coli, Enterococcus faecium, Lysinibacillus fusiformis, Paenibacillus illinoisensis, Staphylococcus epidermidis, S. hominis, Streptococcus equinus, S. lutetiensis, and Saccharomyces cerevisiae. Indicator microorganisms isolated from organic dairy farms were tested for susceptibility to 20 types of antimicrobials. E. coli (ATCC 25922) isolated from dairy farm fence showed resistance to 8 types of antimicrobials, such as oxacillin, penicillin, vancomycin, etc., and E. faecium isolated from feces showed resistance to 9 types of antimicrobials, such as cephalothin, oxacillin, streptomycin, etc., respectively. However, these results showed less antimicrobial resistance compare with customary dairy farm.

• Korean Journal of Veterinary Research
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• v.25 no.1
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• pp.53-59
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• 1985

A group of 80 Holstein calves, many with clinical signs of infectious bovine keratoconjunctivitis in summer seasons, was assembled for bacteriologic and ophthalmologic studies at an integrated dairy farm. Observations were started from 1980 to 1984 but bacteriological study was only carried out from thor spring in 1981 and continued during the Autumn in 1981. Corneal lesions and drugs sensitivity were also observed and the results obtained were as follows: 1. Occurrences of IBK-affected cattle during the 5 years were predominent to calves in summer. 2. Among 142 eyes from 80 cattle, 53 isolates of Moraxella bovis(37.3%) were isolated from 37 cattle(46.3%). The prevalence of the infection for clinical eyes were higher than nonclinical eyes calves. 3. Miscellaneous organisms were found from age groups of 5 months to 9 months old. It were 8 hemolytic Neisseria spp., 3 Fungi, Mycoplasma sp. and 1 Pseudomonas sp., but 9 samples were unknown. 4. Prevalence of infection with M. bovis in bilateral clinical eyes were higher than unilateral eyes. 5. Incidence of corneal lesion was predominent in early stage as a watery tears(21.0%) and late stage as a leukomas of corneal opacity(22.8%). 6. The number of isolations of M. bovis and incidence of IBK varied from year to year; Higher incidence of IBK clinical signs were showed in calves from 5 months to 10 months old and the number of isolations of M. bovis was declined in order 8 months(100.0%), 4 months(75.0%), 5 months(66.6%) and 8 months(66.6%) old calves. 7. Chloramphenicol, Nitrofurantoin and Cephalothin were highly sensitive against M. bovis isolates and then Tetracycline, Neomycin, Erythromycin and Kanamycin were intermediate but low sensitive to Streptomycin, Colistin and Penicillin.