• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.4
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• pp.528-533
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• 2008

Staphylococcus aureus is a pathogene of major concern in livestock products. This study was conducted to test imported and domestic meat sold by retail stores for the presence S. aureus. In addition, the antibiotic susceptibility of any S. aureus found was also evaluated. The overall isolation rate of S. aureus was 20.2% (13.9% in pork and 33.8% in beef) in retail meats. The percentage of imported meats found to contain S. aureus (33.3% in pork and 40.4% in beef) was higher than that of domestic meat (13.0% in pork and 14.7% in beef). In addition, the detection rate of S. aureus was higher in raw material meat than in ready to cook packaged meat. When the antibiotic susceptibility of S. aureus isolated from the meat products was evaluated, ampicillin was found to be the highest (76.5%), followed by penicillin (75.3%), tetracycline (27.1%) and erythromycin (21.2%). Penicillin and tetracycline resistant were detected in 55.6% and 13.3% of the beef isolates, respectively, and 97.5% and 42.5% of the pork isolates, respectively. The tetracycline and erythromycin resistant plasmids of the isolated strain were transferred into S. aureus DPRMM2429 by the filter mating method and the frequencies of transfer was found to be $1.1{\times}10^{-5}{\sim}1.9{\times}10^{-9}$ and $1.2{\times}10^{-5}{\sim}4.0{\times}10^{-8}$ respectively.

• Pediatric Infection and Vaccine
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• v.7 no.2
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• pp.225-232
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• 2000

Purpose : The use antimicrobial agents is one of the important strategies for the treatment and prophylaxis of microbial infections. But injudicious abuse and misuse of antimicrobial agents is problem to add an extra weight on medical fee, increase of resistant bacteria and side effects according to the antibiotic use. This study was performed to establish the pertinent use of antimicrobial agent in Chonbuk National University Hospital(CNUH). Characteristics of antibiotics use was analysis by reviewing the medical records of patients admitted to CNUH during the period of May 1998. Methods : One thousand eight hundred and thirty three patients were enrolled in this study(medical division 1,014 cases, surgical division 819 cases). Medical records were retrospectively reviewed to classify the rate of antibiotics use, name of antibiotics used, appropriateness of antibiotics use. Results : The overall rate of antibiotic usage in CNUH was 67.2%(1,231/1,833), showing higher rate in surgical division(89.6%) compare to that of medical division(49.0%). Among 1,231 patients to whom antimicrobial agents were given, only 125(10.2%) were treated with single antimicrobial agents. 311(25.3%) were treated with two antimicrobial agents, and 795(64.5%) patients received 3 or more antibiotics. ${\beta}$-lactams(56.4%) were most frequently used followed by aminoglycosides(35.3%), the others(4.9%) and quinolons(3.4%). Amoxicillin-clavulanate was the mostly commonly used antibiotics followed by amoxicillin and unasyn. Prophylactic use of antibiotics was carried in seven hundred six patients(57.4%), mostly in surgical division, which can be considered somewhat inappropriate in the initiation time and duration of antibiotic use. Conclusion : Importance of monotherapy and appropriate prophylactic antibiotic use should be emphasized. Strategies of antibiotics use, such as restriction of drug use, continuous monitoring system, flow sheet system should be considered to reduce antibiotics use and establish the appropriate use of antibiotics as well as inhibiting the occurrence of resistant strains.

• Journal of Veterinary Clinics
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• v.31 no.3
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• pp.194-198
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• 2014

Methicillin-resistant staphylococci (MRS) are emerging as important pathogens in humans and animals worldwide. The aim of this study was to investigate the prevalence of MRS in the racehorse population and in horse-related personnel in Korea. A total of 195 horses and 18 humans (eight veterinarians, three veterinary hospital staff, and seven horse-handlers) from racehorse farms in Korea were included in the study. The samples were collected from nasal cavities using bacterial transport medium and were cultivated on tryptic soy agar with 5% sheep blood for 3 days at $37^{\circ}C$ to confirm the presence of Staphylococcus spp. Presumptive Staphylococcus spp. isolates were identified by 16S ribosomal RNA gene analysis. The coagulase test and oxacillin susceptibility tests were performed using the tube dilution and disk diffusion methods, respectively. The presence of the mecA gene was determined using a polymerase chain reaction assay. Of the 195 horses, 29 (15.6%) yielded 29 MRS isolates. Twelve (66.7%) of the 18 horse-related personnel yielded 12 MRS isolates. All of the MRS isolates from horses or horse-related personnel were identified as methicillin-resistant coagulase-negative staphylococci (MRCNS). The result of this study suggest that the prevalence of MRS increased with the duration of antibiotic use (p = 0.002). This study also provides evidence for the zoonotic transmission of MRCNS between horses and humans, although further investigations are needed.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.456-464
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• 2005

Antimicrobial drug-resistance is natural response to antimicrobial stress based on selection, which weakens chemotherapy effect. Introduction of large numbers of chemotherapeutic agents to clinical practice has generated strains of microorganisms that survive and multiply in vivo with high-drug concentrations. Methicillin-resistant Staphylococcus aureus (MRSA), bacteria found in normal daily life, can be easily ingested through milk vegetables, and meats, etc. MRSA emerged in many port of the world, increasing complex clinical problems. Therefore, new agents are needed to treat MRSA. Glycyrrhiza uralensis was extracted using 80% MeOH to investigate its antimicrobial activity against MRSA stains KCCM 11812, 40510, and 40512 through bacterial measurement, disc diffusion, and O.D. methods, MIC values, MRSA gene expression investigation, and scanning electron microscope observation. Results revealed MecA, Mecl, MecRI, and FemA were the most highly manifested MRSA genes. Methanolic extract of G. uralensis significantly inhibited MRSA and thus could be used in development of antibacteria.

• Pediatric Infection and Vaccine
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• v.22 no.1
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• pp.16-22
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• 2015

Purpose: The aim of this study was to identify the factors influencing the spontaneous decolonization period of vancomycin resistant enterococcus (VRE) species in pediatric patients. Methods: The medical records of patients presenting positive VRE cultures between January 2005 and November 2010 at a tertiary hospital in Seoul, Korea, were reviewed retrospectively. The subjects were divided into two groups according to the average number of days for decolonization (325 days). Clinical characteristics were compared between shorter VRE colonization patients (<325 days, n=41) and prolonged VRE colonization patients (>325 days, n=110). Results: There were 151 patients who had more than 1 year of follow up period or confirmed of VRE decolonization among patients who were identified with VRE. The average age at the time of initial VRE colonization was significantly younger in shorter decolonization group than in prolonged decolonization group (44.9 months vs 40.9 months, P =0.040). The prolonged decolonization group received more vancomycin treatments after VRE colonization in comparison with patients in shorter decolonization group (7.0% vs 27.2%, P =0.008). Conclusion: For the duration of VRE colonization, it was found that the initial age of acquiring VRE and use of antibiotics were important factors. Antibiotics should be used properly and precisely in order to treat infectious diseases and to control the colonization of antibiotic resistant bacteria.

• Food Science of Animal Resources
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• v.26 no.1
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• pp.106-112
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• 2006

Fifty four acid-resistant and bile-resistant isolates of lactic acid bacteria were initially isolated from the faces of Korea native cattle and Holstein using MRS agar and LAPT agar, and ten strains with superior activity against bile salt were finally selected LS1, LS15, and LL6 isolates showed survival of 66.5%, 82.6% and 80.7% against the simulated stomach liquid(pH 2.5), respectively. LL6 and LL7 isolates had the highest inhibitory activities against the pathogenic bacteria such as Salmonella typhimurium, Staphylococcus aureus, and Clostridium perfringens. By using API 50 CHL kit LS1, LS2 and LM1 isolates were identified as a L. fermentum. LL6 and LL7 isolates as a L. acidophilus, and LS3 isolate as a L. plantarum. The other four isolates belong to genus Lactobacillus. All the isolates tested were sensitive to some antibiotics such as ampicillin, amoxicillin and erythromycin, but resistant to colistin and ciprofloxacin. LB1, LL6 and LL7 isolates were resistant to gentamicin and neomycin. Especially, the LL6 isolate showed the highest resistance to both of the simulated stomach liquid and bile salt, in addition to the highest inhibitory activities against Sal. typhimurium, Staph. aureus and Cl. perfringens.

• KSBB Journal
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• v.14 no.4
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• pp.460-464
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• 1999

Methicillin-resistant Staphyloccus aureus (MRSA) has been known to be resistant to many kinds of antibiotics and causes a problem of nosnocomial infection since the third generation of cephalosporines has been introduced in the 1980s. As antibiotic sensitivity tests which have been routinely used to detect MRSA in the laboratory depend on the culture conditions such as, pH, temperature, and time, etc., it is difficult to decide in the case of borderline- or low-level of MRSA. Therefore it would be necessary to develope a new method based on the molecular biological technique to overcome these problems. In this study, we extracted DNA from S. aureus and performed polymerase chain reaction (PCR) to amplify mec A gene, encoding penicillin-binding protein 2' (PBP-2'), which is known to confer bacteria resistance to the bacteriostatic action of methicillin. The results were compares with those of minimal inhibitory concentration (MIC) test. When MIC test with oxacillin was performed on the 120 isolates of S. aureus from each patient's specimens, 64 of them were MRSA and 56 of them were methicillin-sensitive Staphylococcus aureus (MSSA). In pus specimen, more precisely, 61.9% (26/42) of MRSA was detected, and 44.2% (19/43), 60% (9/15) and 50% (10/20) of MRSA were detected in sputum, body fluid, and other specimen respectively. When 40 isolates of MRSA and MSSA were tested by PCR method and compares with the results of MIC method, different results were obtained from 1 isolate of MRSA (2.5%) and in 2 isolates of MSSA (5%) suggesting that PCR method should be performed at the same time for more accurate clinical test of MRSA.

• Korean Journal of Veterinary Service
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• v.43 no.2
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• pp.79-88
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• 2020

The aim of this study was to investigate the prevalence of CTX-M β-lactamase and plasmid-mediated quinolone resistance (PMQR) genes, and the pattern of antibiotic resistance in cefotaxime-resistant gramnegative bacteria. A total 126 gram-negative bacteria were isolated from hospitalized dogs and cats between 2018 and 2019. The most predominant isolates were E. coli (n=41), followed by Pseudomonas aeruginosa (n=25), Proteus mirabilis (n=14), Klebsiella pneumoniae (n=9), Sphingomonas paucimobilis (n=7), and Enterobacter cloacae and Serratia marcescens (respectively, n=5). Cefotaxime-resistant isolates were identified in 26.2% (33 isolates) of 126 gram-negative bacteria. CTX-M type β-lactamase were found in 15 isolates (10 E. coli, 1 Ent, cloacae and 4 K. pneumoniae, respectively). Among the CTX-M producing gram-negative bacteria, CTX-M-1 and CTX-M-9 were detected in 10 (66.7%) and 5 (33.3%) isolates, respectively. While, CTX-M-2 and CTX-M-8 were not found. PMQR genes were detected in 12 (36.4%) isolates (4 E. coli, 2 Ent, cloacae and 6 K. pneumoniae, respectively), and the predominant PMQR gene was aac(6')-lb-cr (n=9), followed by qnrB (n=8) and qnrS (n=1) alone or in combination. qnrA and qepA were not found. Additionally, 9 (60%) of 12 PMQR positive isolates were co-existence with CTX-M-1 or CTX-M-9. CTX-M or PMQR producing isolates showed highly resistance to penicillins (100%), cephalosporins (100~66.7%), monobactams (72.2%), and non-β-lactam antibiotics (94.4~61.1%) such as quinolones, trimethoprim/sulfamethoxazole, tetracycline and gentamicin. These findings showed CTX-M-1, CTX-M-9, aac(6')-lb-cr and qnrB were highly prevalent in cefotaxime-resistant Enterobacteriaceae isolates from companion animals in our region. Moreover, PMQR genes were closely associated with CTX-M type β-lactamase.

• Korean Journal of Veterinary Research
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• v.54 no.2
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• pp.91-99
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• 2014

An antimicrobial susceptibility test was conducted to compare the resistance rates among Campylobacter spp. isolates from dogs (n = 50) raised under diverse conditions and humans (n = 50). More than 60% of Campylobacter (C.) jejuni from dogs and humans showed resistance to nalidixic acid, enrofloxacin and ciprofloxacin. C. jejuni isolates from humans showed higher resistance to tetracycline (83.3%) and ampicillin (91.3%) than those from dogs. None of the C. jejuni or Campylobacter coli isolates from humans or dogs were resistant to erythromycin. Overall, 85% of Campylobacter spp. isolates showed a multidrug resistant phenotype. Nucleotide sequencing analysis of the gryA gene showed that 100% of $NA^R/CIP^R$ C. jejuni isolates from dogs and humans had the Thr-$86^{th}$-Ile mutation, which is associated with fluoroquinolone resistance. flaA PCR restriction fragment length polymorphism (RFLP) typing to differentiate the isolates below the species level revealed 12 different clusters out of 73 strains. The human isolates belonged to eight different RFLP clusters, while five clusters contained dog and human isolates.

• Natural Product Sciences
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• v.20 no.1
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• pp.39-43
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• 2014

Papenfussiella kuromo (PK) is a marine plant and an abundant ecological resource for the future; it is found in almost 80% of the terrestrial biosphere. The aim of this study was to investigate the antibacterial activity of PK against methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant pathogen. The minimum inhibitory concentrations (MICs) of PK hexane fraction (PKH) against 7 strains of MRSA ranged from 1.0 to 2.0 mg/mL. In the checkerboard dilution method, a synergistic effect of the PKH and the antibiotics (oxacillin and norfloxacin) was seen. PKH markedly reduced the MIC of each of the 4 antibiotics against MRSA. The time-kill assay showed that the synergistic activity of PKH and an antibiotic reduced the bacterial counts below the lowest detectable limit after 24 h. These findings suggest that PKH has antibacterial activity, and may be important baseline data in future extensive studies of living marine resources as a source of compounds active against MRSA.