• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.33-33
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• 2003

There prevalence of $\beta$-lactamases bacteria in animals has been increased since 1990s [1]. The resistance in E coli which is mediated by $\beta$-lactamases hydrolyze the $\beta$-lactam ring eventually inactivate the antibiotics [2]. Generally, $\beta$-lactamases can be classified into four main groups and eight subgroups according to their functional and structural characteristics [3]. The detection of $\beta$-lactam antibiotic-resistant bacteria by DNA chip has been described [4]. The chip has a specific probe DNAs that contained the $\beta$-lactam antibiotic-resistant genes which was labeled by multiplex PCR reaction with a mixture of primer sets that were designed to amplify specific gene. Here we report the susceptibility of enteropathogenic E. coli isolated from pigs in Korea using the DNA chip in detecting $\beta$-lactam antibiotic-resistant genes. (omitted)

• Fisheries and Aquatic Sciences
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• v.19 no.10
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• pp.45.1-45.5
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• 2016

As a novel strategy to remove ${\beta}$-lactam antibiotic residues from fish tissues, utilization of ${\beta}$-lactamase, enzyme that normally degrades ${\beta}$-lactam structure-containing drugs, was explored. The enzyme (TEM-52) selectively degraded ${\beta}$-lactam antibiotics but was completely inactive against tetracycline-, quinolone-, macrolide-, or aminoglycoside-structured antibacterials. After simultaneous administration of the enzyme with cefazolin (a ${\beta}$-lactam antibiotic) to the carp, significantly lowered tissue cefazolin levels were observed. It was confirmed that the enzyme successfully reached the general circulation after intraperitoneal administration, as the carp serum obtained after enzyme injection could also degrade cefazolin ex vivo. These results suggest that antibiotics-degrading enzymes can be good candidates for antibiotic residue depuration.

• Korean Journal of Veterinary Service
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• v.30 no.4
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• pp.505-510
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• 2007

This study was conducted to detect ${\beta}$-lactam antibiotic-resistant genes in the 400 E coli isolates from porcine fecal samples in Korea by a DNA chip. The DNA chip contains the specific probe DNAs of the ${\beta}$-lactam antibiotic-resistant genes that had been labeled with a mixture of primer set designed to amplify specific genes (PSE, OXA, FOX, MEN, CMY, TEM, SHV, OXY and AmpC) using a multiplex polymerase chain reaction (PCR). Of 400 isolates 339 contained at least one ${\beta}$-lactamases gene. Resistance to ${\beta}$-lactamases was mediated mainly by AmpC (n = 339, 100%), and followed by TEM (n = 200, 59.0%), CMY (n = 101, 29.8%), PSE (n = 30, 8.9%) and both OXA and SHV genes (n = 20, 5.9%), while the FOX, MEN and OXY genes were not detected. The other sixty-one did not contain any ${\beta}$-lactamase genes even though they were resistant to antimicrobial drugs. In conclusion, the DNA chip system can be used as a rapid and reliable method for detecting of ${\beta}$-lactamases genes, which will help veterinarians select the antibiotics for monitoring and treating of animal diseases.

• Biomolecules & Therapeutics
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• v.31 no.2
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• pp.141-147
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• 2023

Antibiotic resistance has emerged as a global threat to modern healthcare systems and has nullified many commonly used antibiotics. β-Lactam antibiotics are among the most successful and occupy approximately two-thirds of the prescription antibiotic market. They inhibit the synthesis of the peptidoglycan layer in the bacterial cell wall by mimicking the D-Ala-D-Ala in the pentapeptide crosslinking neighboring glycan chains. To date, various β-lactam antibiotics have been developed to increase the spectrum of activity and evade drug resistance. This review emphasizes the three-dimensional structural characteristics of β-lactam antibiotics regarding the overall scaffold, working mechanism, chemical diversity, and hydrolysis mechanism by β-lactamases. The structural insight into various β-lactams will provide an in-depth understanding of the antibacterial efficacy and susceptibility to drug resistance in multidrug-resistant bacteria and help to develop better β-lactam antibiotics and inhibitors.

• Proceedings of the PSK Conference
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• 2003.10a
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• pp.85-87
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• 2003

$\beta$-Lactams are historically and clinically representative antibiotics used for therapeutic purposes. In early days, penicillin (penam antibiotic) and cephalosporin (cephem antibiotic) were found in culture broth of two different filamentous fungi, Penicillium chrysogenum and Acremonium chrysogenum. Since 1970, a variety of $\beta$-lactam structures have been discovered from bacterial cultures including Streptomyces species, which are known as cephamycin, cephabacin (cephem antibiotics), clavulanic acid (oxopenam antibiotic), thienamycin (carbapenem antibiotic), and sulfazecin (monobactam antibiotic). (omitted)

• Korean Journal of Clinical Pharmacy
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• v.20 no.2
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• pp.145-150
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• 2010

In order to investigate the antibiotic prescription pattern for upper respiratory infections (URI), the prescription sheets for outpatients from July 2008 to June 2009 were collected from 7 community pharmacies in Ulsan City, and the prescription pattern of Pediatric and ENT physicians was analyzed. The antibiotic prescription rates of Pediatric and ENT physicians were 63.8% and 61.7%, respectively. It was also observed that the oral antibiotic prescription was 95.6% in Pediatrics and 97.6% in ENT. The most favorable antibiotics by Pediatric physicians were penicillins (21.5%) penicillin-clavulanate (36.4%) and cephalosporins (16.5%), macrolides (11.6%), quinolones (3.5%), and nifuroxazide (3.5%). In case of ENT, the commonly prescribed antibiotics were also penicillin-clavulanate (47.6%), cephalosporins (31.6%), macrolides (11.9%) and sulfonamide (1.3%). The antibiotic combination rate was 7.6% in Peditrics and 1.9% in ENT, among antibiotic prescriptions. The combination of more than two oral antibiotics was examined as 66.8% in Pediatrics and 44.2% in ENT. The common oral antibiotic combination in Pediatrics was prescriptions of two ${\beta}$-lactam antibiotics (54.3%). Among them 83% was the combination of amoxicillin-clavulanate (7:1) and amoxicillin, which could be judged as antibiotic overuse. The next highly prescribed oral antibiotic combination was ${\beta}$-lactam/macrolide antibiotic combination probably for URI (11.3%) and ${\beta}$-lactam/nifuroxazide combination (10.0%) presumably for acute diarrhea. Comparatively the oral antibiotic combination prescribed by ENT physicians was negligible except one physician. In conclusion, the antibiotic over-prescription rate by antibiotic combination was much higher in Pediatrics than ENT, even though both clinical departments showed nealy the similar antibiotic prescription rates.

• Korean Journal of Veterinary Research
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• v.43 no.1
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• pp.113-120
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• 2003

The antimicrobial effect of ${\beta}$-lactam antibiotics, which had ${\beta}$-lactamase inhibitor activity, on Staphylococcus aureus isolated from mastitis was investigated in this study. Out of 166 isolates, 99 isolates (59.6%) produced ${\beta}$-lactamase, and 98 isolates of 99 were ${\beta}$-lactamase positive in above $12.5{\mu}g/m{\ell}$ MIC of penicillin. In the providence distribution, ${\beta}$-lactamase production rate of 4 providence, Gangwon, Gyeonggi, Chungcheong, and Jeolla was 100%, 65.7%, 58.8%, and 50.0%, respectively. Antibiotic activities of ${\beta}$-lactam antibiotics against lactamase positive isolates also were investigated. Antimicrobial effects of ampicillin/sulbactam or amoxicillin/clavulanic acid treated group were better than ampicillin or amoxicillin treated group. In antimicrobial effects on intracellular S aureus, there was no difference 1 hour and 4 hour treatment in control, ampicillin, and amoxicillin group, but in 18 hours treatment, ampicillin/sulbactam or amoxicillin/clavulanic acid had a better effect than ampicillin or amoxicillin (p<0.05).

• YAKHAK HOEJI
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• v.30 no.5
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• pp.232-237
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• 1986

A series of modified poly(acrylic acid)'s containing different levels of 6-aminopenicillanic acid (6-APA), 7-aminocephalosporanic acid (7-ACA) and 6-[D-(-)-$\alpha$-aminophenyl acetamido] penicillanic acid (ampicillin) as pendant groups were prepared. Antibiotic activities of the newly prepared drugs were examined against the various gram-positive and gram-negative bacteria. It was found that ampicillin modified composition posses antibiotic activities against the gram-negative as well as the gram-positive bacteria.

• Applied Biological Chemistry
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• v.40 no.1
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• pp.23-29
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• 1997

To develop novel cephem antibiotics, We have synthesized a new compound, named YH-487, by attaching the thiol and aminothiazole residue to $C_3$ and $C_7$ position of 7-ACA, respectively. Several characteristics such as structure, antibiotic spectrum, action mechanism, stability against ${\beta}-lactamase$ and synergistic effect were investigated. Anti-bactericidal activity of YH-487 against gram-positive and gram-negative bacteria were superior to that of the other cephem antibiotics. We have examined the action mechanisms of YH-487 using penicillin binding protein (PBP) assay, and found that the bactericidal activity was obtained by inhibiting PBP-1A, PBP-1B and PBP-3. YH-487 showed synergistic effect with gentamicin, tobramycin, and amikacin against Pseudomonas aeruginosa. In addition, YH-487 was effective against Enterobacter cloacae in combination with amikacin. Based on the above observations, YH-487 was classified as a novel third-generation ${\beta}-lactam$ antibiotics.

• Biomedical Science Letters
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• v.11 no.3
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• pp.389-396
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• 2005

Resent studies have reported increased isolation of extended-spectrum $\beta-lactamase$ (ESBL) producing strains at several hospital in Korea. We studied to investigate the isolation rates of ESBL strains from clinical isolates of Klebsiella pneumoniae and to characterize differences in types using analyses of genotyping and antibiotic susceptibility test. Antibiotic susceptibility test with confirmation of ESBL by double disk synergy test was performed on the 54 ESBL strains of Klebsiella pneumoniae from a hospital in Busan. Transfer of resistant gene in ESBL strains resistant to 3rd generated antibiotics was confirmed by transconjugation test using E. coli $RG176^{nal(r)}$. blaTEM, blaSHV, blaCTX-M genes were detected by PCR. ESBL producing strains had 100% of resistant rate to ampicillin, azteronam, cefazolin, cefepime and ceftriaxone ($\beta-lactam$ antibiotics). Forty strains of bla TEM$(74\%)$, 41 strains of bla SHV $(76\%)$, 23 strains of bla CTX-M $(43\%)$ were found, respectively. The strains had one or more genes. They had high resistant rates to $\beta-lactam$ antibiotics including cephalosporin. The resistant rates of strains with multiple resistant genes were higher than those of strains with single resistant gene.