• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.555-558
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• 2023

Staphylococcus aureus is a prominent multidrug-resistant pathogen known for its resistance to a variety of antibiotics. To combat this, a wide range of antibiotics, including quinolones, is utilized. While the efficacy of quinolones against S. aureus has been established, the rise in quinolone-resistant strains, particularly in methicillin-resistant S. aureus (MRSA), has necessitated a shift in their usage patterns. Genomic sequencing plays a crucial role as it offers insights into the genetic mechanisms of resistance. Thus, we report the complete genome sequence of an oxolinic acid-resistant strain of S. aureus isolated from sweet potato leaves, a crop commonly cultivated in Korea.

• Bulletin of the Korean Chemical Society
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• v.21 no.9
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• pp.849-854
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• 2000

The protonation and divalent cation complexation equilibria of several quinolone antibiotics such as nalidixic acid (NAL),flumequine (FLU), oxolinic acid (OXO), ofloxacin (OFL), norfloxacin (NOR) and enoxacin (ENO) have been examined by potentiome tric titration and spectrophotometric method. The antibacterial activity of these drugs depends upon the pH and the concentration of metal cations such as Mg2+ , Ca2+ in solu-tion. The apparent ionization constants of NAL, FLU, OXO, OFL, NOR and ENO in aqueous solution were found to be 6.33, 6.51, 6.72, 7.18, 7.26, and 7.53, respectively. In aqueous solution, NAL, FLU and OXO were found to be present mainly as two chemical species : molecularand anionic; but OFL, NOR and ENO were present mainly as three chemical species : anionic, neutral zwitterionic and cationic form, in equilibrium. The pKa1 and pKa2are found to be 6.10 and 8.28 for OFL; 6.23 and 8.55 for NOR; 6.32 and8.62 for ENO, respec-tively. The complex formation constants between OFL, NOR or FLU and some divalent cations are measured at pH 7.5. The 1 : 1 complexes are formed mainly by ion-dipole interaction. FLU has somewhat larger Kf values than OFL and NOR because its molecular size is small and the FLU is present asanionic form at pH 7.5.

• Journal of fish pathology
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• v.18 no.3
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• pp.269-276
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• 2005

The concentrations of quinolones (oxolinic acid; OXA, norlloxacin: NRF & ciprofloxacin: CPF) after oral administration of single doses (20 mg/kg B.W.) were investigated in carp (Cyprinus carpio) kept in freshwater at 20-23$^{\circ}C$. The distribution of the drug was studied after treatment. At points timed, from 1 h to 96 hrs after administration, blood (B), liver (L), kidney (K) and muscle (M) from 5 individuals in each group were collected for analyse with microbiological bioassay method. The peak concentrations were measured at 8 h (L), 12 h (B and K) and 24 h (M) after administration regardless of treated drugs. Considerably high concentrations of CPF (13.8-19.6${\mu}g/m{\ell}$) NRF (11.8-16.9${\mu}g/m{\ell}$) and OXA (10.8-13.9 ${\mu}g/m{\ell}$) were revealed during the 24 h. At the last time point of the experiment (96 h), concentrations of all three quinolones were: OXA, 2.3-6.3 ${\mu}g/m{\ell}$ ; NRF, 3.1-4.5 ${\mu}g/m{\ell}$ ; CPF, 3.0-5.5${\mu}g/m{\ell}$ in samples. The concentrations decreased subsequently, indicating a first rapid redistribution, followed by a slow phase of elimination. The steady state was observed in blood (12-36 h), liver (12-96 h) and muscle (36-96 h) after the initiation of treatment with OXA. Concerning the compartmental concentrations, (L, K. and M/B concentration ratio), the fluctuation of the ratio was founded at different time points, among drugs. For CPF, highest tissue ratios were prolonged in the order of L>K>M (0.65-1.2/0.82-0.93/1.0-1.7) during the experiments. On the other hand, NRF presented L>K>M (0.65-1.3/0.86-1.0) till 24 h, but L>M>K (0.89-1.26) at 36-96 h. OXA showed L>K>M (0.95-2.1) at 1-8 h, M>K>L (0.51-1.0) at 12-36 hand M>L>K (1.0-2.3) at 48-96 h, respectively.

• Journal of fish pathology
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• v.23 no.1
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• pp.37-45
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• 2010

In this study, we carried out research on the level of single and multi-drug resistance of bacteria isolated from cultured flounder Paralichthys olivaceus. One hundred sixty one bacteria were isolated from cultured olive flounder Paralichthys olivaceus in Korea and the isolates consisted of Edwardsiella tarda (n=32), Vibrio ichthyoenteri (n=37), Vibrio spp. (n=54), Streptococcus parauberis (n=28) and Streptococcus spp. (n=10). These E. tarda isolates were highly resistant in the order of tetracycline (84.4%) and oxolinic acid (71.9%). V. ichthyoenteri and Vibrio spp. showed resistance ampicillin (94.6% and 81.5%) and tetracycline (56.8% and 42.6%). S. parauberis isolates were resistant ampicillin (57.1%), tetracycline (57.1%) and erythromycin (35.7%). Of the isolates, 84.4% of E. tarda, 73.0% of V. ichthyoenteri, 57.4% of Vibrio spp., 42.8% of S. parauberis and 70.0% of Streptococcus spp. isolates exhibited multi-drug resistance against more than two antibiotics.

• Research in Plant Disease
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• v.18 no.3
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• pp.240-244
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• 2012

Burkholderia gladioli pv. alliicola CH1 showed typical soft rot symptoms at higher than $20^{\circ}C$ but very weak soft rot symptoms at temperature under $10^{\circ}C$. Among the nine agro-chemicals, oxolinic acid WP, streptomycin + copper hydroxide WP and streptomycin WP were found to be effective for the inhibition of the pathogen in vitro. The results of scanning electron microscopic investigation showed that onion bulbs was macerated by infection of B. gladioli pv. alliicola CH1. B. gladioli pv. alliicola CH1 was able to produce polygalacturonase but did not produce pectin lyase and carboxymethylcellulase. In analysis of the polygalacturonase activity of the isolated pectin-degradation enzymes from B. gladioli pv. alliicola CH1 total protein, three activity bands 45 kDa, 35 kDa, and 29 kDa were detected by the direct (or in-gel) activity staining on SDS-PAGE.

• Journal of fish pathology
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• v.19 no.3
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• pp.267-276
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• 2006

Seventy-five streptococci were isolated from diseased olive flounder, Paralichthys olivaceus in Jeju. Their drug susceptibility and transferable multiple drug resistance were characterized. All isolates were resistant to flumequine (AR) and oxolinic acid (OA) and 26 isolates (34.7%) showed 4～6 multiple resistance of ampicillin (ABPC), AR, doxycycline (DOXY), erythromycin (EM), norfloxacin(NOR), OA and oxytetracycline (OTC) in various combinations. pST9 of a transferable R plasmid was detected from a multiple drug resistance strain, Streptococcus sp., ST9 originated from diseased flounder in Jeju, previously. We performed DNA hybridization to know the distribution of plasmid with the same DNA structure as pST9 in streptococci. Thirteen out of 60 isolates analyzed were positive in colony DNA hybridization and the part of bacteria isolated from raw meal was also hybridized with pST9. It suggested that raw meal is one of the origin of the resistance plasmid and R plasmid with DNA structure differing from pST9 is also involving in multiple drug resistance of the streptococci. In conjugation experiment, we found transferable R plasmid carrying OTC, DOXY and/or EM resistance determinant in the 13 resistance strains. all of the streptococci carrying the transferable R plasmid were similar in RAPD patterns. However, pST -type R plasmid was rare in S. iniae most frequently appearing in flounder farm.

• Research in Plant Disease
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• v.24 no.1
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• pp.41-51
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• 2018

Since fire blight disease on apple and pear was produced in Korea in 2015, there were no registered chemicals to control against this disease. Instead, several antibacterial chemicals that were registered for other bacterial diseases such as soft rot and bacterial spot have been authorized by Rural Development Administration (RDA). However, these chemicals are not tested efficacy for fire blight disease except damage by those treatments on apple and pear in Korea. Thus, we evaluated efficiency using in vitro and in planta assays of antibacterial chemicals such as antibiotics and copper compounds including kasugamycin, oxytetracycline, oxolinic acid and streptomycin, and copper hydroxide, copper sulfate, oxine copper and tribasic copper sulfate, respectively. We also tested two kinds of biological agents. As expected, significant antibacterial effect was observed in vitro test of both antibiotics and copper-based chemicals. In planta test based on disease severity including ooze and water-soaked formation on immature pears, bacterial populations on blooms, and blight lesion formation in artificially inoculated shoots, kasugamycin, oxytetracycline and streptomycin have been shown the most efficiency among tested antibiotics. Four copper-based chemicals tested in this study, control effects are little bit lower than agricultural antibiotics but they seem to be available to use in terms of winter season. Biocontrol agents were also shown possibility to treat in eco-friendly farms. In addition, there are no antibiotic resistance genes in Korean isolates against antibiotics, which were selected for suppression of fire blight in this study.

• Journal of Food Hygiene and Safety
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• v.35 no.5
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• pp.447-451
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• 2020

For this study, we conducted a simultaneous multiresidue analysis of veterinary drugs in cultured fishery products in Chungnam Province in 2018. A total of 115 fishery product samples were obtained from fish farms and fishery production sites located in the province. In all, 29 residual veterinary drugs in the samples were analyzed using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. As a result, veterinary drug residues were only detected in a small number of the 106 samples (92.2%), and the detection rate was 7.8% (9 of 115 samples). The amounts were also below maximum residual limit (MRL) for fishery products, although one sample exceeded the MRL allowed by the Ministry of Food and Drug Safety and was detected in loach. The nine residual veterinary drugs were detected in 8 samples: loach, eel, catfish, freshwater bream, flatfish, rockfish and shrimp. The detected veterinary drugs were oxolinic acid, enrofloxacin, ciprofloxacin, sulfadiazine, flumequine and oxytetracycline. The most frequently detected antibiotic was oxolinic acid, and enrofloxacin exceeded the MRL in loach sample. Residues of most veterinary drugs were either not detected or were below the MRL, and while the status of fishery products is seen as safe overall, current surveillance efforts over veterinary drugs should be continued.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.206-212
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• 1998

This study was undertaken to explore the applicability of glutathione S-transferase (GST) activity as a predictable indicator to monitor chemical pollution in shells and fishes utilized for food. There were some variations in the basal level of GST activity depending on species tested. Ark shells, Anadara satowi, showed the highest normal enzyme activity, followed by catfish and marine mussels, Mytilus coruscus. White clams, Meretrix lusoria, Israeli carp and catfish had lower activity. When A. satowi was exposed to 3-methyl-cholanthrene (3-MC), a prototypic polycyclic aromatic hydrocarbon for 1 week, GST activity decreased by about 30%. This reduction in GST activity induced by 3-MC did not recover until two weeks after the cessation of exposure. GST activity increased in response to 3-MC in most of the other species studied. The GST elevation in M. coruscus attained its maxinum of about 200% at the termination of 3-MC exposure maintaining this level up to 2 weeks, and declined gradually thereafter. 3-MC also induced GST activity in lsraeli carp in a similar fashion to M. coruscus. Phenobarbital induced GST activity both in M. coruscus and lsraeil carp. Other chemicals. such as clofibrate, butylated hydroxyanisole. hexachlorobenzene, and oxolinic acid did not change the enzyme activity significantly in most speciel. Phenol depressed GST activity only in lsraeli carp. These results suggest that the basal level of GST activity is somewhat variable and that the direction of change in response to chemicals seems to be related to its normal activity. The change in enzyme activity can be a preditable indicator of some environmental chemicals such as PAHs and phenol.

• Korean Journal of Plant Resources
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• v.36 no.1
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• pp.100-106
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• 2023

In order to control the fire blight disease, all plants within the radius of the diseased orchard were removed in the early stage of the outbreak, or antibiotics control was performed for prevention. Since the beginning of antibiotics use on plants, the potential for development of resistance to antibiotics by the plant pathogen and unintended detrimental effects on the fruit trees and environment has become a problem. The purpose of this study is to determine the degree of phytotoxicity to fruit trees caused by excessive spraying of the fire blight disease disinfectant and to establish basic data for safe disinfectant guide. We analyzed whether damage to the fruit tree and the maximum residual limit of fruit was exceeded when three kinds of the fire blight disease disinfectants were continuously sprayed in excess of the number of safe use during the growing season. There was no phytotoxicity in apple 'Fuji' and pear 'Niitaka', and oxolinic acid was detected beyond the limit of quantitation in 'Fuji' grown without a bag, and the other disinfectants were detected below the maximum residue limit. When these disinfectants are continuously sprayed in excess of the number of safe, phytotoxicity may remain on the fruit. Therefore, it is necessary to observe the prescribed dilution factor and observe the safe frequency and the timing of use.