• Korean Journal of Veterinary Service
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• v.22 no.2
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• pp.105-111
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• 1999

This survey was carried out to detect the residual antibiotics in muscles of slaughter cattle from slaughter houses in Seoul from 1991 to 1998 using by EEC-4-plate method. The results were summarized as follows ; 1. Residual materials were detected in 402 samples(3.12%) by EEC-4-plate method. The detection ratios were highest in 1995 (9.51%), autumn (39.8%), Kyeonggi province (54.2%), Holestain(60.4%) and male(50.7%). 2. Residual antibiotics for 18 samples were classified as TCs(72.2%), sulfonamides(38.8% ) and $\beta$-lactams(5.5%) by HPLC 3. The residual concentration of oxytetracycline, sulfonamide and $\beta$-lactams were 0.34~15.93ppm, 0.17~1.18ppm and 0.06ppm, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.2
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• pp.158-167
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• 2015

A lateral flow immunoassay kit based on antigen-antibody interactions was developed to detect residues of beta-lactams, quinolones, tetracyclines, and sulfonamides in farmed fish. Group-specific antibodies showing cross-reactivity with other antibiotics in the same group were produced in rabbits. The rabbits were immunized eight times to obtain the maximum titers. Antibodies were extracted from the antisera collected from the immunized rabbits and produced group-specific reactions with antibiotics from the four groups. A kit was prepared that optimize conditions for the antigen-antibody reaction, using colloidal gold conjugated antibodies, and was designed to detect the four groups of antibiotics simultaneously. The kit enabled the detection of antibiotics in the four groups at below maximum residue limits (MRLs), which were $200{\mu}g/kg$ for tetracyclines, $100{\mu}g/kg$ for sulfonamides, $50{\mu}g/kg$ for beta-lactams, and $100{\mu}g/kg$ for quinolones. The cross-reactivity of the antibodies ranged from 10-80% for the sulfonamides, 20-100% for tetracyclines, 38-100% for quinolones, and 20-100% for the beta-lactams, confirming that the antibodies were group specific. The test kit was used 30 times to examine spiked antibiotics at the limits of detection (LODs) and all produced positive results, indicating high sensitivity. The LODs for the assay ranged from 4-20 ng/mL for beta-lactams, 25-50 ng/mL for sulfonamides, 20-100 ng/mL for tetracyclines, and 30-80 ng/mL for quinolones, and there were no false negative reactions at above these LODs. In addition, all of the LODs of the developed kit were correlated with high-performance liquid chromatography (HPLC) data. Our lateral flow immunoassay kit can simultaneously detect antibiotic residues from a large number of fish samples rapidly, strengthening the safety of domestic farmed and imported fish.

• 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.

• Analytical Science and Technology
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• v.23 no.2
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• pp.119-127
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• 2010

An effective method for the simultaneous analysis of ${\beta}$-lactams from surface water was established. After solid-phase extraction with HLB (Hydrophilic Lipohilic Balance) cartridge at pH 2, seven ${\beta}$-lactams (amoxicillin, ampicillin, penicillin G, cefaclor, cefadroxil, cefatrizine and cephradine) were determined using LC/ESI-MS/MS. In this newly established method, correlation coefficients ($r^2$) of calibration curves for seven ${\beta}$-lactams in blank surface water appeared to be 0.9911~0.9995 in the concentration range of 0.01~1.0 ng/mL. The limits of detection (LODs) and the limits of quantificaiton (LOQs) in spiked surface water were shown to be 0.0003~0.0234 ng/mL and 0.0046~0.0778 ng/mL, respectively. The developed method is believed to serve as a rapid and reliable method for the qualitative and quantitative analysis of residual ${\beta}$-lactam antibiotics from aquatic environment.

• Korean Journal of Veterinary Service
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• v.22 no.1
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• pp.93-101
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• 1999

This test process on screening method for the detection of residual antibiotics in milk is simple, economic, sensitive to residual antibiotics and was given approval international organs. Thus, this study was carried out the comparison of Disk assay method and TTC-II method for sensitivity and minimum detectable range of antibiotics in raw milk. The results of this study was summarized as follows ; 1. The number of samples requested for treatment of mastitis was 198 samples. Comparison or analytical results among the methods of TTC-II, disk assay and Delve sp was that TTC-II 37 samples(18.6% ), Disk assay 125samples(63.1%), Delve SP 130 samples(65.7% ) reacted positively. Conformity rate of Delve SP and Disk assay was 70%. 2. Detectable limits of disk assay method in some antibiotics were more sensitive than those of official method(0.05-0.0025ppm in the $\beta$-lactams, 1ppm in two aminoglycoside, 0.2 ppm in one tetracycline, similar in one macrolide) 3. For sensitivity of residual sulfonamides TTC-II was much more sensitive than disk assay. Detectable limits of sulfamethazine and sulfadimethoxine were 30 to 50ppm levels. 4. The best medium preservation period is 1-2 days. 5. Concentration of brome cresol purple related to resistance for B stearothermophilus culture was 24ppm/ml. These results show that disk assay method for screening detection of antibiotics residuces in milk is worthy of use.

• 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 Laboratory Science
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• v.38 no.3
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• pp.166-172
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• 2006

Metallo-${\beta}$-lactamase (MBL) can hydrolyze all ${\beta}$-lactams except monobactams and frequently coexists with various antibiotic resistance genes such as aminoglycoside resistance, sulfonamide resistance gene, etc. Therefore, the effective antibiotics against infections by these bacteria are markedly limited or can't even be found. We tried to search in-vitro antimicrobial combinations with synergistic effects for a VIM-2 type MBL producing Pseudomonas aeruginosa, isolated from clinical specimen. On the selection of antibiotic combinations with synergistic effects, we performed a one disk synergy test, modified Pestel's method, in agar without aztreonam (AZT). The bacteriostatic synergistic effects of this tests were scored as $S_1$ (by susceptibility pattern in agar without antibiotics), $S_2$ (by the change of susceptibility in agar with or without antibiotics) and $S_3$ ($S_1$ + $S_2$) and was classified into weak (1 point), moderate (2 points) and strong (3 points) by $S_3$ score. Subsequently, we carried out the time-killing curve for the antibiotic combinations with the strong synergistic bacteriostatic effect. One VIM-2 type MBL producing P. aeruginosa confirmed by the PCR showed all resistance against all ${\beta}$-lactams except AZT, aminoglycoside and ciprofloxacin. In the one disk synergy test, this isolate showed a strong bacteriostatic synergistic effect for the antibiotic combination of AZT and piperacillin-tazobactam (PIP-TZP) or AZT and amikacin (AN). On the time-killing curve after six hours of incubation, the colony forming units (CFUs/mL) of this bacteria in the medium broth with both combination antibiotics were decreased to 1/18.7, 1/17.1 of the least CFUs of each single antibiotics. The triple antibiotic combination therapy including AZT, PIP-TZP and AN was shown to be significantly synergistic after 8 hrs of exposure. In a VIM-2 MBL producing P. aeruginosa with susceptibility for AZT, the triple antibiotic combination therapy including AZT, PIP-TZP and AN may be considered as an alternative antibiotics modality against the infection by some MBL type. But the antimicrobial combination therapy for many more MBL producing isolates is essential to know as soon as possible for the selection of effective treatment against the infection by this bacteria.

• Journal of Yeungnam Medical Science
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• v.27 no.1
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• pp.8-17
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• 2010

It is important to select appropriate antimicrobials for the treatment of infection according to the results of antimicrobial susceptibility tests (ASTs), yet the clinical isolates are sometimes susceptible to antibiotics that are clinically ineffective or this is due to technical error of the ASTs. So, interpretive reading of ASTs is needed and especially for the ${\beta}$-lactams for treating $Enterobacteriacae$. This review describes the interpretive reading of ASTs according to natural antimicrobial resistance and the mechanisms of mechanisms, with giving special attention to the antibiotics phenotypes for $Enterobacteriacae$. Further, as all the diffent tissues have a different antimicrobial concentration for identical antimicrobials, more information is needed on the antimicrobial tissue distribution for the appropriate treatment of infection. (ED note: I hope you send me the paper.)

• Bulletin of the Korean Chemical Society
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• v.12 no.1
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• pp.75-79
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• 1991

A series of compounds, N-(2-substituted-1-carboxy)vinylazetidinones were successfully synthesized in order to test the hypothesis that biological activities of ${\beta}$-lactam antibiotics could be attributed to the smooth flow of electrons after a nucleophilic attack at the carbonyl carbon in the ${\beta}$-lactam ring. After introduction of aminothiazolylacetamido group at 3-position of the azetidinones, their biological activities were evaluated. Their low activities led to the conclusion that the smooth electron flow in ${\beta}$-lactams in not the sufficient source for the biological activities.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.2
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• pp.133-139
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• 2014

Veterinary antibiotics (VAs) in animal compost and organic fertilizer can have adverse effect on ecosystem and eventually human health. The main purpose of this research was to evaluate feasibility of Charm II system for monitoring residuals of VAs in animal compost and organic fertilizer. Four different VAs (Tetracyclines: TCs, Sulfonamides: SAs, Macrolides: MLs, and ${\beta}$-lactams: ${\beta}$-LTs) were analyzed and total of 100 samples were monitored. Results reveled that SAs in animal compost showed the highest detection frequency (64%) with exceeded concentration of criteria. However, very low detection frequency (0-12%) for ${\beta}$-LTs was observed in animal compost and organic fertilizer. Depending on physicochemical properties of each VAs, detection frequency of VAs was determined. In conclusion, charm II system can be utilized to screen if residual of VAs is in animal compost and organic fertilizer. Also, more research is necessary to establish standard method for analysis of VAs in complex matrix and to minimize adverse effect of VAs from source to environment.