• Korean Journal of Veterinary Service
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• v.23 no.1
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• pp.19-28
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• 2000

There are several main antibacterial susceptibility tests, such as agar dilution method, broth dilution method and disk diffusion technique. Especially, for minimal inhibitory concentration (MIC) test, agar dilution method has been widely used. But that method is so complicated and bothering that it's difficult to treat a large amount of strains. On the other hand, modified broth dilution method(add 1% glucose and 0.018% phenol red as a pH indicator to broth) is fast and easy to perform. Most of all, it can visualize the result by color. The MICs of 22 antibiotics Including penicillins, aminoglycosides, cephalothin, chloramphenicol, lincomycin, ceftiofur, vancomycin and quinolones, erythromycin, colistin. sul-fadimethoxine, trimethoprim for arcanobacterium pyogenes 14 strains, actinobacillus pleuropneu-moniae 41 strains and pasteurella multocida 37 strains, which were collected from porcine during 1996 ∼ 1999, were determined by modified broth dilution method. Actinobacillus pleuropneumoniae was highly susceptible to all kinds of quinolones such as ciprofloxacin, enrofloxacin and norfloxacin and to all aminoglycosides, like gentamicin, apramycin, kanamycin and ampicillin, cephalothin and ceftiofur. But It was quite resistant to solfadimethoxin, colistin and vancomycin. Pasteurella multocida was found to have high susceptibility to ampicillin, cephalothin, chlorampenicol and gentamicin but had mid-degree susceptibility to other aminoglycosides. In addition, it was susceptible to norfloxacin and nalidixic acid, but not to newer fluoroquinolone like ciprofloxacin and enrofloxacin and it was resistant to colistin and kanamycin. Arcanobacterium pyogenes was highly susceptible to most of quinolones such as cipoofloxacin, enrofloxacin and norfloxacin and gentamicin and penicillin G. But it also obtained high resistance against the early quinolone, nalidixic acid and aminoglycosides such as amikacin, apramycin and kanamycin and erythromycin, chlorampenicol, tetracyclin and vancomycin.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.623-628
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• 2010

The distribution of fluoroquinolones was investigated in the carp (Cyprinus carpio) and eel (Anguilla japonica) after an oral dose of 20 mg/kg body weight/day for 35 days. Blood samples were collected at 5 and 10 hours and 1, 2, 3, 5, 7, 9, 13, 20, 30, and 35 days after treatment. The fluoroquinolone concentrations were determined high- performance liquid chromatography with an ultraviolet detector. The recovery rates of fluoroquinolones in the fish samples ranged from 91.4-96.6, 91.2-96.5, and 90.4-98.6% for concentrations of 0.1, 0.5, and $1.0\;{\mu}g/g$, respectively. In the blood of carp, ciprofloxacin, enrofloxacin, norfloxacin, and sarafloxacin reached maximums level of 11.03, 9.37, 9.10, and $9.81\;{\mu}g/g$ 10 hours, 1 day, 10 hours, and 10 hours after treatment, respectively. In the eel blood, these reached maximum levels of 12.65, 11.18, 11.91, and $8.74\;{\mu}g/g$ all at 10 hours. Carp sample concentrations of ciprofloxacin, enrofloxacin, norfloxacin, and sarafloxacin were not measurable 20, 30, 20, and 20 days after treatment, respectively, in all experiments (

• Journal of Veterinary Science
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• v.22 no.6
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• pp.78.1-78.10
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• 2021

Background: Recurrent subclinical mastitis (RScM) due to resistant bacteria has low clinical and bacteriological cure rates, often requiring the culling of cows. The sequential intramammary administration of enrofloxacin hydrochloride-dihydrate (enro-C) followed by ceftiofur HCl may be useful for treating these cases. Objectives: This study assessed the bacteriological and clinical cure-efficacies of the sequentially intramammary administration of enro-C, followed by ceftiofur HCl to treat RScM in Holstein/Friesian cows. Methods: This trial was conducted in a herd with a high prevalence of RScM, and 20 Holstein/Friesian cows were included: 45% suffering subclinical mastitis and 38.9% of the mammary quarters affected. Twenty-nine bacterial isolates in vitro resistant to enro-C were obtained (coagulase-negative Staphylococcus spp, 55.2%; Staphylococcus aureus, 27.6%; Escherichia coli, 6.9%; Streptococcus uberis, 6.9%; Corynebacterium bovis, 3.4%). Polymerase chain reaction-isolated the following genes linked to enro-C resistance: chromosomal (gyrA) and plasmid (aac(6')-lb-cr). The treatments were as follows: twice-daily intramammary infusions of enro-C (300 mg/10 mL) for 5 days. Cows clinically considered treatment failures were also treated with intramammary ceftiofur (125 mg/10 mL, twice daily for 5 days. The clinical and bacteriological cure rates were carried out when completing each treatment phase and at 14 and 21 days, aided by a California mastitis test, somatic cell count, and failure to identify the initially causative bacteria. Results: Enro-C achieved 65% clinical and bacteriological cure rates, and 100% cure rates were obtained after the rescue treatment with ceftiofur HCl. Conclusions: Outstanding clinical and bacteriological cure rates in cows affected by RScM were achieved with the consecutive intramammary infusions of enro-C, followed by ceftiofur HCl.

• Journal of Veterinary Science
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• v.25 no.1
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• pp.6.1-6.11
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• 2024

Background: Chronic bovine mastitis is linked to biofilm-producing Staphylococcus aureus (bp-Sa) or Staphylococcus coagulase-negative (bp-Scn). Objectives: Bp-Sa and bp-Scn were treated with intramammary preparations of either enrofloxacin HCl·2H₂O-dimethyl-sulfoxide-chitosan (enro-C/DMSO/chitosan) or enro-C alone. Their potential to inhibit and degrade biofilm formation in vitro was also assessed. Methods: Milk samples were obtained from the affected quarters in a herd. Phenotypical and genotypical identifications as biofilm-producing Staphylococcus species were carried out. Enro-C/DMSO/chitosan and enro-C alone were assessed to determine their in vitro efficacy in interfering with biofilm formation and their bactericidal effects. A prolonged eight-day treatment with a twice-daily intramammary insertion of 10 mL of enro-C/DMSO/chitosan or enro-C alone was set to evaluate the clinical and bacteriological cures on day 10 in 15 cows per group and the biofilm-inhibiting ability. Results: Fifty-seven percent of the isolates were identified as Staphylococcus spp., of which 50% were bp-Sa, 46% bp-Scn, and 4% Staphylococcus pseudintermedius. One hundred percent of the S. aureus isolated and 77% of Staphylococcus coagulase-negative were biofilm producers. In both groups, the icaA and icaD biofilm-producing genes were identified. The experimental preparation could inhibit biofilm formation, degrade mature biofilms, and have well-defined microbicidal effects on planktonic and biofilm bacteria. The respective clinical and bacteriological cure rates were 100% and 80% for enro-C/DMSO/chitosan and 41.7% and 25% for enro-C alone. Conclusions: Enro-C/DMSO/chitosan eliminates bp-Sa and bp-Scn from cases of chronic bovine mastitis.

• Korean Journal of Environmental Agriculture
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• v.35 no.3
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• pp.166-174
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• 2016

BACKGROUND: The current study developed a monitoring method of 6 veterinary antibiotics (amoxicillin, ampicillin, enrofloxacin, tetracycline, chlortetracycline, oxytetracycline) in agricultural soils using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive electrospray ionization mode.METHODS AND RESULTS: Sample preparation was carried out using acidic acetonitrile and citrate salts followed by purification with dispersive solid phase extraction (d-SPE). Separation on Eclipse Plus C₁₈ column was conducted in gradient of the mobile phase, 0.1% formic acid and 5 mM ammonium formate in methanol (A) and 0.1% formic acid and 5 mM ammonium formate in distilled water (B). The linearity of the matrix-matched calibrations expressed as the coefficient of determination was good with R²≥0.9900. The limit of quantifications (LOQs) ranged from 0.5 to 10 μg/kg for all analytes. Analysis of 51 agricultural soil samples taken in the Republic of Korea revealed concentrations less than 1.9 μg/kg for enrofloxacin, 75.5 μg/kg for chlortetracycline.CONCLUSION: The method was successfully applied to monitor 6 veterinary antibiotics from 51 field incurred agricultural soil samples in 17 provincial areas throughout the Republic of Korea. The developed method was simple, easy, and versatile and can be used for monitoring various veterinary antibiotics in soil.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.636-643
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• 2009

Residual fluoroquinolone levels in animal foods retailed in Korea were monitored according to the method outlined in Korea Food Code using HPLC-FLD and HPLC-ESI-MS/MS for confirmation. The optimum ion transitions were $360{\rightarrow}316$, 342 m/z for enrofloxacin, $332{\rightarrow}314$, 288 m/z for ciprofloxacin, $320{\rightarrow}301$, 230 m/z for norfloxacin, $334{\rightarrow}315$, 290 m/z for pefloxacin, $362{\rightarrow}318$, 261, 334 m/z for ofloxacin, and $262{\rightarrow}201$, 126 m/z for flumequin. Enrofloxacin, ciprofloxacin and norfloxacin residues were found in 12 out of 388 samples. These antibiotics were only found in chicken samples, while no residues were found in beef, pork, milk and egg samples. Using this monitoring method, detection rates of 3.1, 1.3, and 0.3% were obtained for enrofloxacin, ciprofloxacin and norfloxacin, respectively. The levels of enrofloxacin, ciprofloxacin and norfloxacin detected in food samples ranged from 0.01 to 0.73 mg/kg in 12 samples, 0.01-0.03 mg/kg in 5 samples, and 0.12 mg/kg in only a sample, respectively.

• Journal of Veterinary Clinics
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• v.34 no.5
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• pp.381-383
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• 2017

A two-year-old intact male Labrador retriever was presented with generalized erythema, pustule and pruritus. A skin screening test revealed that there were no fleas but bacteria and dermatophytes were present. Blood testing revealed no remarkable findings. The patient was prescribed systemic medication of enrofloxacin 30 mg/kg once a day and itraconazole 10 mg/kg once a day and topical medication of 2% chlorhexidine shampoo twice a week for 2 weeks. Two weeks after the prescription, aerobic culture confirmed that the bacteria were Leclercia Adecarboxylata and Pseudomonas putida was sensitive to enrofloxacin. Therefore, more medicine was prescribed for 4 weeks to alleviate clinical signs. After six weeks of medication, clinical signs were alleviated and skin screening test revealed no remarkable findings. Bacterial and fungal skin infections are common in dogs. However, there are no reports of Leclercia Adecarboxylata infection even in gastrointestinal tract in veterinary medicine. This is the first report of Leclercia Adecarboxylata infection in dogs. This report proved that Leclercia Adecarboxylata can cause skin problem in dogs.

• Korean Journal of Veterinary Service
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• v.40 no.1
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• pp.41-46
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• 2017

The purpose of this study was to investigated the fluoroquinolone (FQ) resistance and presence of gyrA and grlA gene in 87 Staphylococcus pseudintermedius isolates obtained from clinical samples of dogs and cats. Also, the profiles of FQ resistance compared with methicillin resistant S. pseudintermedius (MRSP) isolates. FQ resistance was observed for enrofloxacin (41.4%), ciprofloxacin (39.1%), norfloxacin (36.8%), ofloxacin and levofloxacin (32.2%, respectively), and moxifloxacin (31.0%). Thirty-eight (43.7%) of 87 S. pseudintermedius isolates were resistant to more than one FQ. Twenty-six (64.5%) of 38 FQ resistant isolates were resistant to all the six FQ tested. Of 38 FQ resistant isolates, gyrA gene was detected in all isolates but grlA gene was not found. Moreover, 19 MRSP isolates were resistant to enrofloxacin (63.2%), ciprofloxacin (57.9%), norfloxacin (52.6%), and ofloxacin, levofloxacin and moxifloxacin (47.4%, respectively). FQ resistance were highly prevalence in S. pseudintermedius isolates from dogs and cats. Our results emphasize the prudent use of antimicrobial agents to companion animals is necessary for prevent antimicrobial resistance.

• Journal of Life Science
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• v.23 no.9
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• pp.1133-1139
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• 2013

During the collection of boar semen, bacterial contamination usually occurs. The contamination has deleterious effects both on semen quality and on sow fertility. The majority of contaminants are gram-negative bacteria, especially Serratia marcescens. In this study, we developed a PCR assay for the identification of S. marcescens targeting the luxS gene (GenBank no. EF164926). S. marcescens yielded a specific 306 bp PCR product. However, no amplification was observed in the other strains tested. The detection limit of PCR was $50pg/{\mu}l$ of template DNA of S. marcescens. The antimicrobial susceptibility patterns of S. marcescens isolated from boar semen were tested using the disk diffusion method. Gentamicin, ceftiofur, florfenicol, and neomycin showed high sensitivity in this test. The minimum inhibitory concentration (MIC) was also determined by the broth microdilution method. The $MIC_{90}$ values of ceftiofur, enrofloxacin, gentamicin, and neomycin were 8, 8, 8, and $16{\mu}g/ml$, respectively. These results indicate that PCR amplification of the luxS gene is a reliable and effective method for the identification of S. marcescens and that ceftiofur, enrofloxacin, gentamicin, and neomycin are effective semen extenders for controlling S. marcescens.

• Journal of the Korean Electrochemical Society
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• v.13 no.1
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• pp.63-69
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• 2010

Electrochemical behavior of fluoroquinolone antibacterial agents on carbon paste electrode (CPE) were investigated by cyclic voltammetry and square wave adsorptive stripping voltammetry. The fluoroquinolone antibacterial agents tested in this study were Enrofloxacin (ENR), Norfloxacin (NOR), Ciprofloxacin (CIP), Ofloxacin (OFL) and Levofloxacin (LEV). In acetate buffer at pH 4.5, the oxidation peak potentials of the fluoroquinolone antibacterial agents of ENR, NOR, CIP, OFL, and LEV were 0.952 V, 1.052 V, 1.055 V, 0.983 V, and 0.990 V (vs. Ag/AgCl), respectively. And their oxidation peak currents from square wave adsorptive stripping voltammograms are proportional to the concentration of each antibacterial agent over the range from $0.2\;{\mu}M$ to $1\;{\mu}M$.