• Microbiology and Biotechnology Letters
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• v.27 no.1
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• pp.23-27
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• 1999

The development and industrial application of intestinal anaerbic bacteria is highly important in the munufacture of foodstuffs and medical products. We have conducted studies, screening anaerobic intestinal bacteria for acid and bile tolerance and for pathogens suppression in the intestine of swine. One such study was taxonomic in nature and dealt with the isolate's biochemical responses. The results indicated that the BSA-131 strian ioslated. which suppressed various pathogens (13 typical strains), were identified as Lactobacillus reuterii. The strain, which named L. reuterii BSA-131, was able to tolerate acid condition down to pH2 and could also tolerate bile at 5%. The strain exhibited resistance to a range of antibiotics including, cephalexin, erythromycin, flumequine, furazolidine, gentamycin, penicillin G, norfloxacin, spectinomycin, tetracycline, tiamuline, neomycin, chloramphenicol, kanamycin etc.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.872-880
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• 2003

Three vectors, pSG1, 2, and 3, which facilitate in vivo expression technology (IVET) in Gram-negative bacteria, were developed. Vectors pSG1and 2 are derivatives of ColE1, and pSG3 is a derivative of an R6K replicon. These vectors contain oriT sites that allow mobilization when the RK2 Tra functions are provided in trans. These vectors contain promoterless lacZ (pl-lacZ) and promoterless aph (pl-aph) transcriptionally fused together, which allow qualitative and quantitative measurements of the expression of genes in the genome of bacterial cells. pSG1 and 3 contain gentamicin-resistance genes, and pSG2 carries a streptomycin-/spectinomycin-resistance gene, allowing for selection of recombinants generated by a single crossover between a library fragment cloned into a pSG vector and the identical region in the genome of a bacterial species from which the library fragment originated. These vectors were successfully applied to the generation of random fusions at high rates in the genomes of four representative Gram-negative bacteria. In addition, the expression level of ${\beta}-galactosidase$ and the degree of resistance to kanamycin in cells with fusions generated by these vectors were found to be linearly correlated, proving that these vectors can be used for IVET.

• Korean Journal of Veterinary Research
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• v.57 no.3
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• pp.201-204
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• 2017

A Gram-negative, catalase- and oxidase-positive, coccus-shaped bacterium was isolated from a rabbit with keratoconjunctivitis. Colonies of the isolate were round, smooth, and exhibited hemolytic activity on 5% sheep blood agar. Scanning electron microscopy revealed 0.4 to $0.5{\mu}m$ diameter oval cocci. Partial 16S rRNA gene (1446 bp) sequence analysis demonstrated the isolate had significant homology with the Moraxella cuniculi CCUG2154 strain isolated from a rabbit in Germany in 1973. Our isolate was designated as APQAB1701. Antibiotic susceptibility tests demonstrated that APQAB1701 was sensitive to 24 antibiotics; 3 of the antibiotics (nalidixic acid, spectinomycin, and colistin) had minimal inhibitory concentrations ${\geq}32{\mu}g/mL$ against the isolate.

• Korean Journal of Veterinary Service
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• v.30 no.1
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• pp.1-12
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• 2007

A liquid chromatographic method has been developed for the analysis of aminoglycoside antibiotics (AMGs) using Heptafluorobutyric acid (HFBA) as a ion-pairing reagent. AMGs (amikacin, apramycin, dihydrostreptomycin, gentamicin, hygrosin B, kanamycin, neomycin, spectinomycin and tobramycin) were formed by reaction with HFBA as ion-pairing reagent. HFBA was attached to corresponding amino group of AMGs. These AMGs compounds were separated and detected by electrospray ionization mass spectrometry (ESI-MS). The experimental conditions for separation of AMGs were optimized and validated. A simple liquid chromatographic method for the determination of AMGs was demonstrated.

• Korean Journal of Veterinary Service
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• v.37 no.3
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• pp.165-171
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• 2014

This study was conducted to investigate the species-specific gene detection, capsular serogroup and antimicrobial resistance pattern of Pasteurella multocida isolated from pneumonic lung lesion of swine in Gyeongbuk province. P. multocida isolates were typed for capsular serogroups by polymerase chain reaction. Of the 32 strains, 28 (87.5%) were typed serotype A, 3 (9.3%) were typed serotype D, and 1 strain was unknown (3.1%), respectively. In antimicrobial agents resistance test, almost of strains were susceptible to amoxicillin (100%), enrofloxacin (96.9%), ampicillin (93.8%), florfenicol (90.6%), chloramphenicol (90.6%) and were resistant to streptomycin (71.9%), spectinomycin (56.3%). All strains were resistant to clindamycin, erythromycin and lincomycin.

• Journal of Food Hygiene and Safety
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• v.22 no.2
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• pp.116-119
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• 2007

The antimicrobial susceptibility and antibiotic resistance patterns of 67 eae positive Escherichia coli strains isolated from pigs were investigated by disc diffusion method. Sixty-seven E. coli isolated from pigs showed susceptibility to Ceftiofur (98.5%), Lincomycin+Spectinomycin (74.6%), Danofloxacin (73.1%), Enrofloxacin (64.2%), and Neomycin (41.8%). However, the multiple resistance patterns were also seen in eae+E. coli isolates. Neomycin+Tylosin+Penicillin+Tetracycline, Tylosin+Penicillin+Tetracycline, and Neomycin+Tylosin+Danofloxacin+Penicillin+Tetracycline+Enrofloxacinwere the most prevalent patterns of multiple antibiotic resistance.

• Journal of Microbiology and Biotechnology
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• v.24 no.7
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• pp.1008-1013
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• 2014

The use of antimicrobial agents for additives or therapeutics is strongly associated with a prevalence of antimicrobial resistance in commensal Enterobacteriaceae. We aimed to characterize integrons in Enterobacteriaceae isolates obtained from chicken cecums in Korea. Moreover, the correlation between integron gene cassettes and antimicrobial resistance was also investigated. A total of 90 isolates the belonged to Enterobacteriaceae were recovered from chickens grown at Gyeongsang and Chungcheong provinces in Korea. Antimicrobial susceptibility tests were performed by the disk diffusion method. PCR and DNA sequencing were also performed to characterize the gene cassette arrays of the integrons. Of the 90 Enterobacteriaceae isolates tested, 39 (43.3%) and 10 (11.1%) isolates carried class 1 and 2 integrons, respectively. Whereas the class 2 integron did not contain gene cassettes, the class 1 integrons carried seven different gene cassette arrays. The class 1 integrons harbored genes encoding resistant determinants to aminoglycosides (aadA1, aadA2, and aadA5), trimethoprim (dfrA1, dfrA12, dfrA17, and dfrA32), lincosamides (linF), and erythromycin (ereA). Moreover, the presence of a class 1 integron was significantly related to a high resistance rate of antimicrobial agents, such as spectinomycin and trimethoprim. We confirmed that diverse class 1 integrons were widely distributed in Enterobacteriaceae isolates from chickens and directly contributed to the resistance to diverse antimicrobial agents in Korea.

• Korean Journal of Veterinary Service
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• v.34 no.3
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• pp.209-216
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• 2011

This study carried out to investigate the pathogenic Streptococcus spp. isolated from respiratory tract of Thoroughbred in Jeju province. The specimens were collected from nasal mucosa using a culture swab from 113 Thoroughbred horses. Suspected colonies were selected onto blood and MacConkey agar plate, and identified by standard biochemical properties using Vitek 2 system and PCR method. In this study, we isolated S. equi (n=6), S. zooepidemicus (n=31), S. equisimilis (n=5), S. dysgalactiae (n=2), S. agalctiae (n=1), non identified ${\beta}$-hemolytic Streptococcus spp. (n=1) from Thoroughbred horses. In antimicrobial susceptibility test, it showed a high sensibility in the most of antimicrobial except for neomycin, streptomycin, spectinomycin, erythromycin and clindamycin. These results will provide the basic information to establish control measures for the treatment and prevention of respiratory disease by pathogenic Streptococcus spp. in Thoroughbred horses in Korea.

• Journal of Veterinary Clinics
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• v.28 no.4
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• pp.348-351
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• 2011

The purpose of this study was to determine the distribution of gram-negative bacteria isolated from companion animals with sepsis, and to investigate the antimicrobial susceptibility patterns of the isolates. Bacterial pathogens were isolated from specimens of dogs and cats submitted to National Veterinary Research and Quarantine Service between 2008 and 2009. A total of 44 gram-negative pathogens were isolated from necropsied organs. The most common isolates were E. coli (n = 33), K. pneumoniae (n = 4) and B. bronchiseptica (n = 4). Most of gram-negative isolates were susceptible to ceftiofur (68.2%), colistin (84.1%), florfenicol (84.1%) and spectinomycin (61.4%). Most of those were resistant to ampicillin (77.3%), erythromycin (86.4%), flumequine (65.9%), lincomycin (97.7%), oxytetracycline (61.4%), penicillin (100%), streptomycin (63.6%), spiramycin (97.7%), sulfamethoxazole (90.9%), tylosin (97.7%) and tiamulin (100%). In conclusion, colistin and florfenicol could be useful against sepsis due to gram-negative bacteria.

• Korean Journal of Veterinary Research
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• v.44 no.1
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• pp.89-98
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• 2004

This study was carried out to investigate the serotype, and antimicrobial susceptibility and analyze the plasmid profile for the 145 isolates of L. monocytogenes isolated from livestock products and these product processing plants in Gyeongnam, Korea. All of L. monocytogenes strains belonged to serotype 1/2b (57.9%), 1/2a (20.0%), 4b (11.4%), 1/2c, 3b, 4c (each 2.9%) and 4d (0.7%). Serotype 1/2b, 1/2a, 4b from each source were found predominantly. Serotype 1/2b was predominantly higher than other serotype, and there was no significant difference between serotypes isolated from livestock products and product processing plants. 4b was major serotype isolated from raw milk and pork, and serotypes isolated from beef, chickens and slaughterhouse were 1/2b and 1/2a. The susceptibility of 145 strains of L. monocytogenes to 14 antibiotics commonly used in veterinary and human therapy was determined by disk diffusion method. All of L. monocytogenes strains were susceptible to amikacin, ampicillin, cephalothin, chloramphenicol, gentamicin, kanamycin, neomycin and penicillin. L. monocytogenes strains had the highest resistance with colistin (100%), oxytetracycline (44.8%), tetracycline (43.4%) followed by erythromycin (2.8%), spectinomycin (1.4%) and streptomycin (0.7%). Tetracycline resistance, and serotype distribution of the isolates from sample sources were significantly different. Resistance to at least one antibiotic was observed in all of them and 7 different resistant profiles were recorded. The most common resistance pattern were CL-OTC-TC (colistin-oxytetracycline-tetracycline) (42.8%). Among all tested isolates, two different plasmid profiles were observed. Of the 97 examined strains, 14 (14.4%) contained either the 8 and 11 kb plasmid or the 11 kb.