• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.288-294
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• 2014

Penicillin and its salts, including the benzatine, procaine, and sodium salts, have been widely used in human and veterinary medicine. Owing to their low toxicity, they currently form the most important group of antibiotics. However, overdose and abuse of these antibiotics may lead to potential risk in human health. Therefore, this study was conducted to validate the analysis method established by the Korea Food Code in 2012 and to monitor the levels of benzylpenicillin residues in products with reference to the maximum residue level (MRL). Of the 232 product samples tested, benzylpenicillin was detected in 11 livestock products and 2 marine products. Benzylpenicillin concentrations were found to be lower than the MRL in 12 products; however, the concentration of benzylpenicillin was found to be greater than the MRL in 1 pork product. The limit of quantification (LOQ) for benzylpenicillin was found to be 0.001-0.002 mg/kg, with an average recovery of 90.4-115.3%. Calibrations showed good linearity of 0.995 over a range of 0.002-0.05 mg/kg.

• Journal of Veterinary Clinics
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• v.40 no.6
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• pp.393-398
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• 2023

We identified mastitis-causing pathogens using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) in an organic dairy farm and evaluated the effects of antimicrobial restriction on antimicrobial susceptibility. A total of 43 Holstein cows without any clinical sign of mastitis were used in this study, and 172 quarter milk samples were cultured on blood agar plates for 24 hours at 37℃. Subsequently, bacterial species were identified and antimicrobial susceptibility tests were performed. The subclinical mastitis infection rates in the cows and quarters were 58.1% (25/43) and 25.6% (44/172), respectively. In the species identification, Staphylococcus aureus (40.9%) was the most prominent isolate, followed by S. chromogenes (22.7%), S. epidermis (18.2%), S. simulans (11.4%), S. haemolyticus (2.3%), S. muscae (2.3%), and S. xylosus (2.3%). In the antimicrobial susceptibility test, all isolates were 100% susceptible to 24 of 28 antibiotics, except for benzylpenicillin, cefalotin, cefpodoxime, and trimethoprim/sulfamethoxazole. The resistance rates of S. aureus, S. chromogenes, and S. muscae isolates to trimethoprim/sulfamethoxazole were 27.8%, 10%, and 100%, respectively, and the resistance rates of S. epidermis and S. xylosus to benzylpenicillin were 50% and 100%, respectively. S. chromogenes, S. epidermis, S. simulans, S. haemolyticus, and S. xylosus were resistant to cefalotin and cefpodoxime. In conclusion, restrictions on antimicrobial use for organic dairy farm certification have resulted in a high Staphylococcus spp. infection rate. Therefore, our study indicates the importance of mastitis management strategies implemented by farmers together with veterinary practitioners, even if mastitis does not appear clinically in organic dairy farms.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3315-3322
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• 2015

Staphylococcus aureus is the major causative organism of nasocomial infection being the important pathogen in the clinic. Appearance of staphylococcus aureus resistant to methicillin (MRSA) is becoming a big problem in clinics and dynamics all over the world acquiring antibiotic resistance with virulence factors as its feature differentiated from other pathogenic bacteria fast. This research intended to compare and analyze the correlation of antibiotics resistance between strains with toxin genes and distribution of toxin genes of MRSA 101 strains acquired from clinical specimen in one general hospital (enterotoxin(se), toxic shock syndrome toxin-1(tst), exfoliative toxin(et), Panton Valentine leukocidin(pvl)). seg gene, isolated the most among toxin genes, was detected in 59 strains (58.4%) and more than two toxin genes were detected in 70 strains (69.3%). As a combination possessing toxin genes, it was detected in 19 strains (18.8%) as seb, sec, seg, sei, tst and the second frequent combination was sec, seg, sei shown in 11 strains (10.9%). 19 strains (18.8%) with combinations of toxin genes same with seb, sec, seg, sei, tst had 100% resistance Ampicillin, Benzylpenicillin, Ciprofloxacin, Clindamycin, Gentamicin, Erythromycin, Telithromycin, Tetracycline antibiotics. Strains with many toxin genes showed high correlation of antibiotic resistance. Afterwards, effective therapy and thorough infection management should be preceded not to spread the resistance of MRSA strain.

• Journal of Veterinary Clinics
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• v.3 no.1
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• pp.243-253
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• 1986

In recent years much attention has been paid to swine respiratory infection caused by Haemophilus(H.) Pleuropneumoniae with rapid expansion of pork industry in Korea. The organism may cause an acute respiratory infection with high morbidity and mortality, or it may also cause chronic persistent infection, resulting in loss of body weight. The present study was performed to observe the etiologic situation of H. Pleuropneumoniae infection by evaluating bacteriological, serological examinations with the lungs and sera collected from slaughtered pigs in Daegu city, respectively. In addition, antibiotic susceptibility test was carried out against the isolated strains of H. Pleuropneumoniae. The results obtained are summarized as follows : 1. Only 10 strains of H. Pleuropneumoniae were isolated from the 120 cases of swine lungs examined, and biological and biochemical characteristics of the isolates were identical with that of standard strains(serovar 1 to 6). 2. Out of 336 swine sera examined, 108(32.1%) were shown to be positive against H. Pleuropneumoniae by latex agglutination test. 3. Antibiotic susceptibility test revealed that 10 isolates of H. Pleuropneumoniae were sensitive to 16 kinds of antibiotic such as ampicillin, benzylpenicillin, piperacillin, cephalothin, cefazolin, cefamandol, cefoperagon, lactomoxycefa, tetracycline, minocycline, chloramphenicol, gentamicin, kanamycin, amikacin, colistin and nalidixic acid, whereas cloxacillin, erythromycin, kitasamycin, lincomycin, oleand-amycin, and bacitracin were resistent.

• Journal of Pharmaceutical Investigation
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• v.35 no.2
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• pp.111-116
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• 2005

The unstirred water layer (UWL), which has been known to exist in the boundary of the intestinal lumen and intestinal wall, often behaves as an absorption barrier especially for lipophilic drugs. The intestinal absorption of drugs is often characterized using Caco-2 cell monolayers grown on Transwell polycarbonate membranes. The permeability $(P_{app})$ of drugs across the cell monolayer might be influenced by the agitation of the donor compartment, since the width of UWL on the surface of the cell monolayer would be reduced by the agitation. In this study, the effect of agitation of the donor compartment with 60 rpm on the permeability was measured for 12 drugs with a wide range of lipophilicity and permeability. The $P_{app}$ of mannitol, tributylmethyl ammonium, cimetidine, ranitidine, hydrocortisone, benzylpenicillin and loxoprofen was not influenced by the agitation, while the $P_{app}$ of theophylline, propranolol, YH439, phenylpropanolamine and testosterone was increased by the agitation. There was a significant correlation between the increase of $P_{app}$ by agitation and the lipophilicity for the compounds having $P_{app}>2{\times}10^{-5}$ cm/sec. No correlation was observed for the difference in $P_{app}$ by agitation and the molecular weight, or lipophilicity of the drugs. Therefore, the agitation rate of the donor compartment in the Caco-2 cell monolayer study should be carefully controlled in order to estimate $P_{app}$ reproducibly especially for lipophilic drugs.

• Analytical Science and Technology
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• v.25 no.4
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• pp.257-264
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• 2012

Penicillins belong to the ${\beta}$-lactam class of antibiotics, and are frequently used in human and veterinary medicine. Despite the positive effects of these drugs, improper use of penicillins poses a potential health risk to consumers. This study has been undertaken to determinate multi-residues of penicillins, including amoxicillin, ampicillin, oxacillin, bezylpenicillin, cloxacillin, dicloxacillin, and nafcillin, using liquid chromatographic tandem mass spectrometer (LC-MS/MS). The developed method was validated for specificity, precision, recovery, and linearity in livestock and marine products. The analytes were extracted with 80% acetonitrile and clean-up by a single reversed-phase solid-phase extraction step. Six penicillins presented recoveries higher than 76% with the exception of Amoxicillin. Relative standard deviations (RSDs) were not more than 10%. The method was applied to 225 real samples. Benzylpenicillin was detected in 12 livestock products and 7 marine products. Amoxicillin, ampicillin, cloxacilllin, dicloxacillin, nafcillin and oxacillin were not detected. The detected levels were 0.001~0.009 mg/kg in livestock products excluding eggs and milk. In marine products, the detected levels were under 0.03 mg/kg. They were under the MRL levels. As monitoring results, it is identified to be safe but it is considered that safety management of antibiotics should continue by monitoring.