• Korean Journal of Veterinary Service
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• v.21 no.2
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• pp.141-148
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• 1998

Eighteen strains of Clostpidium perfringens were isolated from the piglets with hemorrhagic enteritis. The characteristics of the outbreaks, clinical signs and lesions were examined. The biochemical properties, type of toxins and susceptibility to antimicrobial agents against the isolates were investigated. 1. The incidence of diarrhea was appeared in 97(22.4%) of 432 piglets examined. 2. The isolation rate of Cl perfingens from the 97 diarrheal faeces were 18.5%(18 strains) 3. The population of Cl perfingens in feces were ranged $10^{8-9}$cfu/g in 5(32.5%) and $10^{3-7}$cfu/g in 13(67.4%) of 18 samples. 4. The toxin type of the 18 isolates investigated by mouse inoculation test was all type C strains of Cl perfringens. 5. As a results of antimicrobial susceptibility test, 18 isolates were higly susceptible to cephalothin, tetracycline and penicillin.

• Korean Journal of Veterinary Service
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• v.33 no.3
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• pp.255-261
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• 2010

At the present study, it was aimed to explore the states of antimicrobial resistant Staphylococcus aureus isolates from 320 pigs and cattle carcass (160 pigs and 160 cattle) slaughtered in Busan province from March 2008 to November 2009. Among 320 samples, 26 of Staphylococcus aureus were isolated from pigs (10.6%) and cattle (5.6%). In antimicrobial susceptibility test, all of the isolates were demonstrated susceptibility to oxacillin, cefoxitin, cephalothin, vancomycin, rifampin and linezolid. But the isolates were showed resistance other antibiotics in order of penicillin (92.3%), gentamicin (76.9%), tetracycline (69.2%), erythromycin (65.4%), and clindamycin (61.5%). In case of enterotoxin production, 7.7% of 2 strains produced enterotoxin A.

• Korean Journal of Veterinary Research
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• v.27 no.1
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• pp.61-68
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• 1987

This study was conducted to determine the microorganisms inhabitating in cow genitalia and their antimicrobial drug susceptibility. During the period between July, 1985 and February, 1986, a total of 111 cow genitalia, 58 from Korean native and 53 from dairy cow, were sampled at three abattoirs. Gross pathological examination and bacterial isolation and identification were performed from the genital samples. In addition antimicrobial drug susceptibility test for the microorganisms isolated, some synergistic activity among drugs were examined on the major organism isolated from the cases of endometritis and pyometra. The results are summerized as follows: 1. Among the bacteria isolated from the genitalia, Staphylococcus spp., C. pyogenes, E. coli, Proteus spp., Streptococcus spp., Bacillus spp. were most frequently isolated whereas the genera of Pasteurella, Pseudomonas, Klebsiella and Yersina were detected far less frequently. 2. In Korean native cow the genera of Straphylococcus and Steptococcus were more isolated than dairy cow while in dairy cow the genera of Corynebacterium, Proteus, Escherichia were more of ten isolated than Korean native cow. 3. From cow genital organs showing lesions of endometritis and prometra, C. pyogenes was most frequently isolated, the isolation rate being 60 percent, and follow by Staphylococcus spp., Proteus spp., E. coli and Pasteurella spp. in the order. 4. Antimicrobial drug susceptibility test conducted on the major organisms isolated showed that all the isolates were susceptible to gentamicin, cephalosporin and sulfisoxazole, but resistant to tetracycline and penicillin. 5. Twenty-nine isolates of C. pyogenes were submitted to the synergistic activity test of cephalosporin, kanamycin and streptomycin with penicillin. Synergists were demonstrated in 90 percent, 31 percent and 27 percent of isolates examined by the combined use of penicillin and cephalosporin, penicillin and kanamycin, penicillin and streptomycin, respectively. About 10 percent of the isolates were found to be indifferent by the synergism test.

• Journal of Veterinary Clinics
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• v.40 no.6
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• pp.393-398
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• 2023

We identified mastitis-causing pathogens using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) in an organic dairy farm and evaluated the effects of antimicrobial restriction on antimicrobial susceptibility. A total of 43 Holstein cows without any clinical sign of mastitis were used in this study, and 172 quarter milk samples were cultured on blood agar plates for 24 hours at 37℃. Subsequently, bacterial species were identified and antimicrobial susceptibility tests were performed. The subclinical mastitis infection rates in the cows and quarters were 58.1% (25/43) and 25.6% (44/172), respectively. In the species identification, Staphylococcus aureus (40.9%) was the most prominent isolate, followed by S. chromogenes (22.7%), S. epidermis (18.2%), S. simulans (11.4%), S. haemolyticus (2.3%), S. muscae (2.3%), and S. xylosus (2.3%). In the antimicrobial susceptibility test, all isolates were 100% susceptible to 24 of 28 antibiotics, except for benzylpenicillin, cefalotin, cefpodoxime, and trimethoprim/sulfamethoxazole. The resistance rates of S. aureus, S. chromogenes, and S. muscae isolates to trimethoprim/sulfamethoxazole were 27.8%, 10%, and 100%, respectively, and the resistance rates of S. epidermis and S. xylosus to benzylpenicillin were 50% and 100%, respectively. S. chromogenes, S. epidermis, S. simulans, S. haemolyticus, and S. xylosus were resistant to cefalotin and cefpodoxime. In conclusion, restrictions on antimicrobial use for organic dairy farm certification have resulted in a high Staphylococcus spp. infection rate. Therefore, our study indicates the importance of mastitis management strategies implemented by farmers together with veterinary practitioners, even if mastitis does not appear clinically in organic dairy farms.

• Korean Journal of Veterinary Research
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• v.52 no.3
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• pp.177-181
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• 2012

Actinobacillus (A.) pleuropneumoniae is the causative agent of pleuropneumonia which is one of the most important respiratory diseases in pigs worldwide. A total of 32 A. pleuropneumoniae isolates from diseased pigs during 2008 to 2010 were serotyped by polymerase chain reaction method. The susceptibility of the isolates to 13 antimicrobial agents were determined by disk diffusion test. In all the 32 isolates examined in this study, serotype 5 (16 isolates: 50%), 1 (7 isolates: 21.9%), 2 (5 isolates: 15.6%) and 12 (1 isolate: 3.1%) were found. Of all tested antimicrobial agents, resistance to oxytetracycline was found in 96.9% of isolates, followed by resistance to amikacin (81.2%), neomycin (68.7%), kanamycin (53.1%), penicillin (50.0%), gentamicin (43.7%), florfenicol (25.0%), ampicillin (18.7%), colistin (9.4%), trimethoprim/sulfamethoxazole, ceftiofur (8.3%), amoxicillin/clavulanic acid (3.1%) and enrofloxacin (0%). Oxytetracycline or florfenicol-resistant isolates were examined for the presence of resistance gene. Among the 31 oxytetracycline-resistant isolates, tetB, tetH and tetO genes were detected in 22 (71%), 8 (26%) and 1 (3%) isolates, respectively. The floR genes were detected in 8 (100%) of the 8 florfenicol-resistant A. pleuropneumoniae isolates.

• Korean Journal of Veterinary Research
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• v.39 no.6
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• pp.1091-1098
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• 1999

Antimicrobial susceptibility, plasmid profiles and distribution of toxA gene were investigated in Pasteurella multocida isolated from pneumonic lung lesions of swine. The bacteria were highly susceptible to norfloxacin, cabenicillin, enrofloxacin and chloramphenicol, but resistant to colistin, sulfamethoxawle/trimethoprime, bacitracin, streptomycin. Sixty percentage of the isolates was resistant more than 2 drugs used in this experiment and 21 strains (23.6%) were resistant more than 5 drugs. This phenomenon meant that they had highly multi-drugs resistance. In the analysis of plasmid profiles, nineteen strains (47.5%) of 40 P multocida isolates harbored plasmids, ranging from 53.3kb to 2.49kb in size and the plasmid profiles could be classified into 5 groups. However, there was no relationship between the size and the profile of plasmid and the resistance pattern of antimicrobial agents. Thirty strains of 39 P multocida isolates (77%) investigated by PCR harbored toxA gene. This result suggested involvement of the ToxA protein expressed from the gene in pneumonic pasteurellosis of swine.

• International Journal of Oral Biology
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• v.36 no.4
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• pp.163-166
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• 2011

Oral viridans streptococci are recognized as one of the etiological agents of a variety of infectious diseases such as dental caries and infective endocarditis. Although antimicrobial susceptibility tests for these fastidious bacterial species are now established and standardized, a comparison between the broth microdilution and broth macrodilution tests has not previously been performed. This comparison was performed in the present study using the tests adopted by the Clinical and Laboratory Standards Institute (CLSI) and seven clinical isolates of oral viridans streptococcal strains. A modified broth macrodilution susceptibility test method was also included in this analysis, in which the media was not supplemented with horse blood. The susceptibility interpretation category agreements were measured at 83% (broth microdilution versus broth macrodilution) and 71% (broth microdilution versus modified broth macrodilution). The interpretation category agreement between the broth macrodilution and modified broth macrodilution tests was also 83%. These data indicate that the interpretation of antibiotic susceptibility test results for oral viridans streptococci are influenced by the methods used.

• Korean Journal of Veterinary Service
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• v.31 no.3
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• pp.339-345
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• 2008

This survey was carried out to investigate the infection rate of Riemerella anatipestifer from domestic ducks by isolation. A total of 145 samples (nasal swabs and carcasses) were collected from farms to examine the biochemical properties and antimicrobial susceptibility test from November 2006 to February 2008. Riemerella anatipestifer was isolated from 13 of 145 sample and isolation rate was higher in the ducks below 25 days (76%, 10/13 isolates) than those over 26 days (23%, 3/13). However, there was no significant difference in isolation rate between region. The biochemical properties of isolate were Gram negative (-), non-fermentative rod that grows fastidiously on routine media. In the test of antimicrobial drug susceptibility the isolates were susceptible to tetracycline(100%), enrofloxacin (77%), ampicillin (70%).

• YAKHAK HOEJI
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• v.36 no.5
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• pp.433-439
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• 1992

For the synthesis of tuberin derivatives, N-(disubstituted styryl) carboxamides, the series of cinnamic acids were transformed through chlorides, azides to isocyanates. And then isocyanates were reduced separately by Dibal and Grignard reagent. As a result of antimicrobial susceptibility test, N-(3,4-dichlorostyryl) formamide and N-(3,4-dichlorostyrl) acetamide showed comparatively large activity against some bacteria that is, MIC was respectively 50 ppm, $6.25{\sim}50\;ppm$. MIC of other derivatives was similiar to that of tuberin, about 100.

• Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.221-227
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• 2013

In total, 131 Escherichia coli isolates from surface seawater of the Gomso Bay, of Korea, were analyzed for their susceptibility to 22 different antimicrobials and for genes associated with antimicrobial resistance and virulence. According to the disk diffusion susceptibility test, the resistance to tetracycline was most prevalent (33.6%), followed by that to ampicillin (22.1%), ticarcillin (22.1%), and trimethoprim (16.8%). More than 46.6% of the isolates were resistant to at least one antimicrobial, and 22.9% were resistant to three or more classes of antimicrobials; these were consequently defined as multidrug resistant. We further found that 29 ampicillin-resistant isolates possessed genes encoding TEM-type (93.1%) and SHV-type (6.9%) ${\beta}$-lactamases. Among the 44 tetracycline-resistant isolates, tetA and tetC were found in 35 (79.5%) and 19 (43.2%), respectively, whereas tetB was detected in only three isolates (6.8%). With regard to virulence genes, merely 0.8% (n = 1) and 2.3% (n = 3) of the isolates were positive for the enteroaggregative E. coli-associated plasmid (pCVD432) gene and the enteropathogenic E. coli-specific attaching and effacing (eae) gene, respectively. Overall, these results not only provide novel insight into the necessity for seawater sanitation in Gomso Bay, but they help reduce the risk of contamination of antimicrobial-resistant bacteria.