• Korean Journal of Veterinary Service
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• v.29 no.2
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• pp.111-122
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• 2006

A direct, accurate and sensitive chromatographic analytical method for quantitative determination of four fluoroquinolones (norfloxacin, cirprofloxacin, danofloxacin and enrofloxacin) in chicken, pork and beef edible muscle is proposed in the present study. The developed method was successfully applied to the determination of enrofloxacin, as the main component of commercially available veterinary drugs. The samples were homogenized and the antimicrobials were added, then they were extracted twice with dichloromethane. Fluoroquinolone antibiotics were separated on an agilent $250x4mm,\;C_{18},\;5{\mu}m$, analytical column, at $25^{\circ}C$. The mobile phase consisted of a mixture of DW : acetonitrile : triethylamine(80:19:1%, v/v, pH 3.0) leading to retention times less than 14 min. at a flow rate 0.5 ml/min. These fluoroquinolones were detected by liquid chromatography with fluorescence at 290 nm excitation and 465 nm emission. The limits of quantification in each edible muscle (chicken, pork, and beef) were 0.32-6.54 ng/g. Using 0.5 g of each sample, average recovery rates at fortification levels of 0.05, 0.1 and 0.2 ${\mu}g/ml$ ranged 70.14-71.71% for NFX, 71.87-73.89% for CFX, 82.16-92.35% for DFX, and 90.13-98.12 for EFX This is a simple and economic method to quantify the presence of NFX, CFX, EFX and DFX in edible muscle of animal origin.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3275-3279
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• 2014

A mass balance method for purity assessment of thermolabile organic reference materials was established by combining several techniques, including liquid chromatography with UV/VIS detector (LC-UV), Karl-Fischer (K-F) Coulometry, and thermal gravimetric analysis (TGA). This method was applied to three fluoroquinolones like enrofloxacin, norfloxacin and ciprofloxacin. LC-UV was used to analyze structurally related organic impurities based on UV/VIS absorbance spectra obtained in combination with LC separation. For all three organic reference materials, the UV/VIS spectra of the separated impurities were similar to that of the major component of the corresponding materials. This indicates that the impurities are structurally related to the respective reference material sharing common chromophores. Impurities could be quantified by comparing their absorbances at the wavelength of maximum absorbance (${\lambda}_{max}$). The water contents of the reference materials were measured by K-F Coulometry by an oven-drying method. The total inorganic impurities contents were assayed from ash residues in TGA analysis with using air as a reagent gas. The final purities estimated from results of those analytical techniques were assigned as ($99.91{\pm}0.06$), ($97.09{\pm}0.17$) and ($91.85{\pm}0.17$)% (kg/kg) for enrofloxacin, norfloxacin and ciprofloxacin, respectively. The assigned final purities would be applied to the reference materials which will be used as calibrators for the certification of those compounds in matrix CRMs as starting points for the traceability of their certified values to SI units.

• Korean Journal of Veterinary Service
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• v.30 no.1
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• pp.13-21
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• 2007

An atmospheric pressure chemical ionization (APcI) LC/MS/MS method was developed for the simultaneous analysis of fluoroquinolones (norfloxacin, ciprofloxacin, enrofloxacin, danofloxacin) residues in eggs. The spiked and blank samples were extracted from whole eggs using 50mM phosphate buffer (pH 7.4). The extract was cleaned up by passage though $Oasis^{(R)}$ MAX extraction cartridge for solid-phase extraction followed by elution with 4% formic acid in methanol. The extract of sample was separated on a Waters $Atlantis^{TM}$ $dC_{18}$ reversed-phase column ($4.6{\times}150mm,\;5{\mu}m$) and analyzed by APcI positive mode mass spectrometry. The mobile phase consists of aqueous 0.2% nonafluoropentanoic acid (NFPA) and methanol. Multiple reaction monitoring (MRM) using the precursor to product ion combinations of m/z $320\;{\dashrightarrow}\;302,\;332\;{\dashrightarrow}\;314,\;360\;{\dashrightarrow}\;342$ and m/z $358\;{\dashrightarrow}\;340$ were used to quantify norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENR) and danofloxacin (DAN), respectively. The limits of quantification (LOQ) were 7.8ppb for NOR, 8.5ppb for CIP, 8.9ppb for ENR, and 4.8ppb for DAN. Average recoveries of fortified sample at levels of 0.025 to 0.1 ppm were estimated 71.29% for NOR, 75.27% for CIP, 85.51% for ENR and 81.22% for DAN. These results could be applied for the confirmation and quantification in eggs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.59-65
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• 2006

Fluoroquinolones are the most common group of antibacterial agents currently used in the Korean aquaculture industry, and use of these agents has been increasing steadily. High performance liquid chromatography (HPLC) with fluorescence detection was used for the simultaneous determination of five fluoroquinolones in fish and shellfish: ofloxacin (OFL), pefloxacin (PEF), norfloxacin (NOR), ciprofloxacin (CIP), and enrofloxacin (ENRO). Fish and shellfish muscle was homogenized, and protein, lipid, and low molecular weight pigments were then excluded from the homogenate. The final eluates were analyzed by HPLC equipped with a Shiseido UG-120 type C18 reverse-phase column ($4.6{\times}250 mm$, $5{\mu}m$) and a fluorescence detector (excitation at 280 nm, emission at 450 nm). The mobile phase was 0.1 M phosphoric acid and acetonitrile solution (91:9, v/v) and tetrahydrofuran (THF) was added to it at a rate of 5 mL per a liter of the mobile phase. Adequate chromatography separation was obtained using the above method. Average recoveries of fortified samples at levels from 0.05 to 0.5 mg/kg were $72.3{\pm}2.5-84.5{\pm}1.2%$ for OFL, $82.7{\pm}3.3- 109.3{\pm}7.5%$ for NOR, $85.3{\pm}6.6-116.0{\pm}7.9%$ for PEF, $76.0{\pm}4.3-109.3{\pm}12.4%$ for CIP, and $78.7{\pm}5.9-100.0{\pm}9.8%$ for ENRO. The limit of detection of OFL was $5{\mu}g/L$, the others were $1{\mu}g/L$. We concluded that the new analytical method was suitable for the determination of fluoroquinolones in fish and shellfish.

• Journal of Veterinary Clinics
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• v.11 no.2
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• pp.507-516
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• 1994

The purposes of this investigations were survey of the occurred bacterial diseases, development of new animal health drug, guidance to formers on the treatment and control methods of diseases. Some series of investigations have been carried out by microbiological, pathological and serological examinations. The results could be summarized as follows. 1. A total of 953 cases of outbreaked swine diseases have been diagnosed in Clinical pathology laboratories, Bayer Vet Res Institute during 8 years (from 1986 to 1993). The high incidence diseases were colibacillosis, pleuropneumonia, streptococcal infection and pasteurellosis in decreasing order. 2. Pleuropneumonia caused by Actinobacillus pleuropneumoniae was the most important respiratory diseases and pasteurellosis by Pasteurella multocide could be confirmed in several cases. 3. Actinobacillus pleuropneumoniae 50 strains were isolated and identified by biochemical and serological tests. In serotyping test, 22 isolated strains were serotype 5, 21 strains as serotype 2, each 2 strains as serotype 3 and 7 by the coagglutination test. 4. Colibacillosis and edema discase caused by Escherichia coli has been the most predominant outbreaked disease in this investigations. The 100 isolates of E coli strains were sensitive to amikacin, colistin, enrofloxacin, gentamycin and trimethoprim -sulfamethoxazole. 5. Swine erysipelas caused by Erysipelothrix rhusiopathiae was confirmed 25 cases as acute septicemic forms. Isolates of E rhusiopathiae were highly sensitive to ampicillin, cephalothin, enrofloxcin, penicillin and tetracycline. 6. The 49 cases of hemorrhagic and necrotic enteritis in piglets were observed and 13 strains of Clostridium perfringens could be isolated and confirmed by biological and serological test. Isolates of Clostridium perfringens type C were highly sensitive to ampicillin, cephalothin, enrofloxacin, penicillin and trimethoprim- sulfamethoxazole. 7. The 14 strains of Streptococcus suis type II could be isolated from meningitis of piplets. 8. Polyserositis caused by Haemophilus parasuis and salmonellosis were observed and confirmed. Also Corynebacterial infections and several parasitosis have been also observed in this investigations.

• Journal of Veterinary Clinics
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• v.30 no.4
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• pp.305-309
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• 2013

Pyometra is a diestrual, chronic disease process with acute manifestations in the adult, ovary-intact bitch. Serosal inclusion cysts develop during postpartum involution as mesothelium becomes trapped during rapid uterine contraction. A 10-year-old golden retriever bitch presented with lethargy, anorexia, tachypnea, abdominal distention, and abnormal vaginal discharge. Radiographic, ultrasound, and laboratory examinations were performed. On ultrasound examination, the uterus was distended by fluid containing echogenic "snow storm" particles; cystic structures containing anechoic fluid were found adjacent to the body of the uterus. Leukocytosis, neutrophilia, and anemia were diagnosed by a complete blood cell count. The initial diagnosis was pyometra, and an ovariohysterectomy was performed. Macroscopically, the uterine body and horns were expanded and partially adhered to the abdominal wall; numerous cysts containing clear fluid protruded over the entire surface of the uterus. Escherichia coli that was sensitive to enrofloxacin, was cultured from the lumen of the uterus. Histopathological assessment confirmed a final diagnosis of pyometra and serosal inclusion cysts of the uterus.

• Korean Journal of Veterinary Research
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• v.52 no.2
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• pp.133-139
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• 2012

Antimicrobial resistance is one of the most concerns in pig industry. Escherichia (E.) coli have been used for the indicator to monitor the antimicrobial resistance. In this study, 321 E. coli from diarrheic and non-diarrheic piglets were tested for antimicrobial resistance and frequency of $Bla_{TEM}$. In non-diarrheic piglets, they were resistant to oxytetracycline (93%), streptomycin (92%) and sulfadiazine (90%) but susceptible to ceftiofur (99%), colistin (97%), and enrofloxacin (82%). The isolates from diarrheic piglets were resistant to enrofloxacin (72.9%), ceftiofur (17.6%), and colistin (11.3%), whereas the resistance was 1%, 18% and 3% in case of non-diarrheic piglets, respectively. The resistance for amoxicillin/clavulanic acid (54.1%) and ceftiofur (22%) was high in isolates from post-weaning piglets. The resistance for colistin was 15.2% in nursery piglets. Seventy-three percent of isolates from diarrheic piglets showed high multidrug resistance profile (more than 13 antimicrobials) compared to those from non-diarrheic pigs in which 71% of isolates showed moderate multidrug resistance profile (7 to 12 antimicrobials). The frequency of $Bla_{TEM}$ in E. coli from non-diarrheic and diarrheic piglets was 57% and 69%, respectively. The results might provide the basic knowledge to establish the strategies for treatment and reduce antibiotic resistance of E. coli in piglets.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.868-872
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• 2007

The microbiological and chemical identification of antibiotic residues was attempted for livestock and seafood products including pork (n=34), beef (n=34), chicken (n=32), flatfish (n=37), armorclad rockfish (n=36), and sea bream (n=27). The meat (n=100) and seafood (n=100) samples were collected from 9 markets in 5 major Korean cities. Antibiotic substances were identified from the classes of tetracyclines, macrolides, penicillins, aminoglycosides, polyethers, peptides, sulfonamides, quinolones, chlorampenicols, and novobiocins using a microbiological assay, the Charm II test and high performance liquid chromatography (HPLC) with ultra violet (UV) and fluorescence detectors. The results showed that 2 tetracyclines (oxytetracycline and tetracycline) and 3 quinolones (ciprofloxacin, norfloxacin, and enrofloxacin) were detected in 4 samples of flatfish among all 100 seafood samples tested. No antibiotic residues were detected in the 100 livestock product samples tested. The amounts (min-max, mg/kg) of the residual antibiotics were as follows; tetracycline 0.78-0.85, oxytetracycline 0.49-0.74, ciprofloxacin 0.09-0.83, norfloxacin 0.01-0.21, enrofloxacin 0.12-2.98. These data indicate that the total detection rate of antibiotics in livestock and seafood products was approximately 2%.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.521-526
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• 2010

A high-performance liquid chromatography (HPLC) method was established for the determination of fluoroquinolones in milk. Protein was removed by using trichloroacetic acid in order to increase a mean recovery of milk. The extracts were using $Strata^{TM}$-X solid-phase extraction cartridge. The analytes were detected by HPLC on a $C_{18}$ column. HPLC method with fluorescence detection system (Ex: 278 nm, Em: 456 nm) provided a high degree of sensitivity in detecting fluoroquinolones. The limits of quantitation (LOQ) and mean recoveries of fluoroquinolones were 40 ${\mu}g$/kg and 73.6-95.2% (ofloxacin), 10 ${\mu}g$/kg and 77.3-91.9% (norfloxacin), 20 ${\mu}g$/kg and 91.6-94.3% (ciprofloxacin), 10 ${\mu}g$/kg and 81.0-87.8% (enrofloxacin), 10 ${\mu}g$/kg and 71.3-81.0% (sarafloxacin), 10 ${\mu}g$/kg and 89.4-90.8% (orbifloxacin), 2 ${\mu}g$/kg and 69.4-85.5% (danofloxacin).

• Journal of Veterinary Clinics
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• v.27 no.1
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• pp.6-10
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• 2010

Bacterial pathogens were isolated from dogs with urinary tract infection (UTI) in local animal hospitals between August 2003 and December 2009. Bacteria were isolated from urine of 47 dogs. The isolated pathogens were Escherichia coli (n = 27), Streptococcus spp. (n = 7), Staphylococcus spp. (n = 5), Enterobacter spp. (n = 3), Proteus spp. (n = 2), other species were 3 strains, respectively. E. coli were susceptible to imimpenem, polymyxin B, amikacin, cephalosporins, aztreonam, amoxicillin clavulate, cephalosporins, tricarcillin, and amoxicillin clavulate, while were resistant bacitracin, erythromycin, lincomycin, oxacillin, penicillin, and novobiocin. Streptococcus spp. were susceptible to bacitracin, imimpenem, and trimethoprime-sulfa, while were highly resistant amikacin, cefotaxim, cefoxitin, cloxacillin, gentamicin, lincomycin, oxacillin, penicillin, streptomycin, and tobramycin. Staphylococcus spp. were susceptible to cefoxitin, doxycycline, enrofloxacin, imimpenem, and tobramycin, but were resistant aztreonam and tetracycline.