• Korean Journal of Veterinary Research
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• 제39권2호
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• pp.376-382
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• 1999

A methicillin-resistant Staphylococcus aureus (MRSA) isolate was recovered from a 9-month-old female Shih-Tzu dog with canine distemper virus infection. We performed in vitro antimicrobial susceptibility test to determine the most effective antimicrobial drug against the isolate and thus, to emphasize its potential clinical importance in animal practices. Isolate was confirmed MRSA by oxacillin agar screening test. The isolate was fully resistant to all $\beta$-lactam antibiotics and was susceptible to glycopeptides. Of the other antibiotics, mupirocin, TMP/SMZ (trimethoprim-sulfamethoxazole), and chloramphenicol showed inhibitory effect at the concentration of 4x MIC. The MICs ranged 0.25->$128{\mu}g/ml$, and MBCs ranged 0.5->$128{\mu}g/ml$. The combined TMP/SMZ with cefamandole or novobiocin showed synergistic effect, whereas the combination of novobiocin plus cefamandole or teicoplanin resulted in antagonistic effects. Although MRSA in animals so far has been reported in the geographically limited countries, at least theoretically, it could be occurred in the future more frequently through either human or animal origin. The use of this combination may be of value in this situation. As with all antimicrobial agents, inappropriate or unnecessarily prolonged therapy may contribute to the emergence of resistance strains and loss of efficacy.

• Biomedical Science Letters
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• 제11권4호
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• pp.447-453
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• 2005

A total of 108 strains of MRSA (Methicillin-resistant Staphylococcus aureus) clinical isolates was collected from $121^{st}$ general hospital (U.S. military hospital), Korean healthcare facility from January to March in 2005 and Wonju Christian hospital in 1999. Antimicrobial susceptibility test by Vitek System and MIC test using oxacillin and cephalothin stripes by E-test were executed. PCR based detection of mecA gene was performed on the all of MRSA clinical isolates, too. MRSA clinical isolates were characterized with antimicrobial resistance patterns, PCR based detection of mecA gene and validation of the multiplex PCR strategy of SCCmec among clinical isolates.

• Korean Journal of Veterinary Research
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• 제44권1호
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• pp.151-157
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• 2004

Samples of milk were collected from 425 halves of 216 dairy goats in Chonnam province over a period of January through August 2003. Bacterial isolation was carried out on those samples, and their antimicrobial susceptibility was tested. Bacteria were isolated from 166 milk samples (39.1%), either singly (74.7%) or in combination (25.3%). Of the 220 isolates, Staphylococcus spp. was the most prevalent (82.6%), followed by Streptococcus spp. (2.7%), Corynebacterium spp. (1.8%), Enterococcus spp. (1.8%), and Pasteurella spp. (1.8%). Of the 11 species identified from the 182 isolates of Staphylococcus spp., the most frequent species identified were S. epidermidis (28.6%) followed by S. chromogens (14.8%), S. haemolyticus (12.6%), S. aureus (12.1%), S. capitis (8.2%), S. lentus (8.2%), S. hyicus (4.4%), S. simulans (4.4%), S. caprae (2.8%), S. hominis (2.8%) and S. warneri (1.1%). Antimicrobial sensitivity test revealed that most isolates were highly susceptible to 11 antimicrobial agents (96.4 ~ 80.9%), while most isolates were resistant to penicillin.

• Korean Journal of Veterinary Research
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• 제47권1호
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• pp.67-75
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• 2007

Environmental mastitis has increased particularly in well-managed or low somatic cell countherds that have successfully controled contagious pathogens. Major pathogens of environmental mastitisare Escherichia coli (E. coli) and Streptococcus uberis. The present study was conducted to investigate1,865 quaters of 241 Korean dairy farms from 2001 to 2004. Prevalence of major gram-negative bacteriaisolated from mastitis milk were E. coli (22.7%) and Enterobacter spp. (16.3%) in coliforms and Pseudomoassp. (10.3%) and Serratia spp. (7.9%) in non-coliforms. The results on antibiotic susceptibility by agardifusion test against these pathogens were 86.7% in piperaciliin, 94.6% in cefepime, 85.5% in amikacin,87.7% in gentamicin and so on. In contrast, the susceptibility against ampicillin (41.9%), cephalothin (9.9%),streptomycin (39.9%) and tetracycline (46.7%) appeared to be below 50%. Gram-negative bacteria showed(96.8%). Acording to year, distribution of high $256{\sim}64{\mu}g/ml$ on cephalothin get increased, but the othersare diferent. These findings demonstrate that major gram-negative bacteria were E. coli and Enterobacterspp. isolates, and often encountered the diverse antibiotic resistant patterns.

• The Journal of the Korean dental association
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• 제52권7호
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• pp.425-431
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• 2014

Objectives : The purpose of our study was to evaluate penicillin as a still drug of choice for severe endodontic infection, by analyzing the antimicrobial susceptibilities from endodontic infections with swelling to figure out appropriate antibiotics as empirical treatment. Materials and methods : This study involved 18 patients who attended for emergency treatment because of facial or periapical swelling associated with root canal infections. Identification and antimicrobial susceptibility test of each pathogen were performed by Vitek2 Systems (bioM$\acute{e}$rieux, Marcy l'Etoile, France). Results : The most frequent bacteria was Streptococcus spp.(77%), and the resistance against penicillin was 35% in overall patients, followed by clindamycin and erythromycin (17%), which was much higher than previous studies. Conclusions : In our study, the higher resistance made penicillin alone not to be chosen as the first antibiotic drug for severe endodontic infections. Combinations with other drug, penicillin with wider spectrum of activity, or changing to other antibiotics was considered while remembering the increased risk of resistant microorganism.

• Korean Journal of Veterinary Service
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• 제33권1호
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• pp.51-57
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• 2010

Salmonella Typhimurium is a virulent pathogen for human and animal. We studied serotypes, biochemical characteristics, and antimicrobial resistance of S. Typhimurium isolated from diseased pigs in Gyeongbuk province over 1998 to 2008. One hundred sixteen isolates were identified as S. Typhimurium by biochemical characteristics and serotypes from 90 farms. The biochemical characteristics of S. Typhimurium isolates was production of $H_2S$, indole-negative, fermentation of mannitol, dulcitol, sorbitol, inositol, rhamnose, and maltose, and ornithine decarboxylase. At antimicrobial susceptibility test, the majority of isolates were highly susceptible to amoxicillin/clavulanic acid, cefepime, ciprofloxacin, while were highly resistant streptomycin, cephalothin, enrofloxacin, nalidixic acid, apramycin, chloramphenicol, tetracycline. The isolates were divided into 65 resistant patterns and 47 of the isolates were shown as a DT104 ASSSuT resistant phenotype.

• The Korean Journal of Food And Nutrition
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• 제27권2호
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• pp.213-218
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• 2014

The enterotoxin production and antimicrobial susceptibility on hemolytic strains from stools of diarrheal pigs was investigated in this study. Through morphological observation, gyrB nucleotide sequence, and API kit analysis, the selected potential pathogenic strain BY06 was identified as Bacillus cereus. Because the characteristic of enterotoxin symptoms were widely caused by Bacillus cereus strains, a PCR test was carried out in order to check the enterotoxin genes (hblA) in this strain. According to the results, this strain was an enterotoxin positive strain containing the hblA gene. The minimum inhibitory concentrations of 10 different antimicrobial agents were screened by the agar dilution test, indicating that this strain was resistant to penicillin G and intermediate to erythromycin; however, it susceptible to cephalothin, vancomycin, clindamycin, fusidic acid, gentamicin, ciprofloxacin, tetracycline and rifampin. These results suggest that the B. cereus BY06 isolated from pig feces has a potential risk of producing enterotoxin and is resistant to penicillin G, but susceptible to various antimicrobial agents.

• Korean Journal of Veterinary Research
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• 제34권3호
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• pp.593-599
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• 1994

This study was carried out to investigate the necrotic enteritis of chicken in Korea. Epidemiological, pathological and microbiological examination were done on 12 naturally occurred cases of necrotic enteritis of chicken. And the susceptibility of isolated bacteria to antimicrobial agents was also examined. The results obtained were as follows; 1. The Clostridium perfringens infection, necrotic enteritis of chicken, occurred in the chickens mainly raised in floor pens. Necrotic enteritis of chicken was occurred coincidently with coccidiosis and Gumboro disease frequently. And several cases were recurred at 2-3 weeks after recovery. 2. Clinical signs of the infected chickens were depression, decreased appetite, reluctance to move, diarrhea, ruffled feathers and acute death within several hours. 3. The characteristic biochemical properties of isolates were 2-band hemolysis, no motility, positive reaction of reverse CAMP test and the formation of LV precipitate in egg yolk medium. 4. Gross lesions of the infected chickens were distention of intestine with gas, thickened mucosa and formation of thick pseudomembrane in intestine. Livers were friable with yellowish brown color and, in some case, showed demarcated necrotic foci. 5. Histopathological findings of the infected chickens were severe necrosis of the intestinal mucosa and attachment of numerous large bacilli to the mucosal surface of necrotic villi. In liver, necrosis of liver tissue and numerous large bacilli in the necrotic foci were also observed. 6. In susceptibility test to antimicrobial agents, 12 isolates of Clostridium perfringens were highly sensitive to ampicillin, baytril, cephalothin and penicillin.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제49권6호
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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.

• Korean Journal of Veterinary Research
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• 제47권1호
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• pp.33-41
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• 2007

Streptococcus spp. comprising Streptococcus (S.) uberis S. dysgalactiae strains is major causeof bovine mastitis from particularly well-managed or low somatic cell count herds that have successfullycontrolled contagious pathogens. In this study, antimicrobial susceptibility and genetic characteristics of S.uberis isolated from clinical or subclinical mastitis milk at 2003 were investigated. Eighty seven isolatesof Streptococus spp. were identified by the conventional biochemical methods. The antimicrobialsusceptibility by disk diffusion method was determined for 46 S. uberis, 11 S. bovis, 10 S. oralis, 6 S.uberis and 14 other Streptococcus spp.. Overall, the tested strains were susceptible to tetracycline (11.5%),amikacin (14.9%), streptomycin (16.1%), neomycin (26.4%), kanamycin (35.6%), gentamicin (65.2%),oxacillin (70.1%), ampicillin (75.9%), chloramphenicol (78.2%), and cephalothin (97.7%). Additionally, S.uberis strains were susceptible to pencillin G (97.8%), but resistant to erythromycin (76.0%) by minimalinhibitory concentration test. The multiple-drug resistance rate of isolated bacteria to 4 more thanamplification fingerprinting patterns amplifed with primer 8.6d showed that 3 to 8 number of distinguishableDNA fragments ranged from 180 bp to 1,20 bp. Thirty seven isolates of S. uberis strains were subtypedinto 8 distinct patterns. Each subtype revealed a typical pattern of antimicrobial susceptibilities. Thesefindings demonstrate that S. uberis isolates were mastitis pathogens of diverse serotypes, and oftenencountered the diverse resistant patterns.