• Korean Journal of Veterinary Service
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• v.44 no.1
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• pp.21-26
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• 2021

The aim of this study was to investigate the antimicrobial resistance among Pseudomonas (P.) aeruginosa isolated from dogs and cats. A total of 45 (6.2%) P. aeruginosa was isolated from 710 dogs and 21 cats with clinical signs. Resistance to one or more of the antimicrobials tested was observed in 26 (57.8%) P. aeruginosa. Resistance to cefepime was the most frequent (44.4%), followed by ofloxacin (22.2%), levofloxacin (17.8%), norfloxacin (8.9%), ciprofloxacin (6.7%), ceftazidime, aztreonam, colistin, polymixin B and gentamicin (4.4%, respectively), while resistance to piperacillin/tazobactam, imipenem, tobramycin and amikacin was 2.2%, respectively. All isolates were susceptibility to doripenem and meropenem. Antimicrobial susceptibility testing should be a crucial step in selection of appropriate antimicrobial therapy in veterinary medicine. Also, the prudent use of antimicrobials and continuous monitoring for companion animals are required.

• Biomedical Science Letters
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• v.18 no.3
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• pp.299-306
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• 2012

Recently, the prevalence of 16S rRNA methylase conferring high-level resistance to aminoglycosides has been increasing in Gram-negative bacilli globally. We determined the prevalence and genotype of these methylase-producing bacteria, and characterized the co-resistance to ${\beta}$-lactam antibiotics and quinolone in Gram-negative clinical isolates collected in 2010 at a hospital in Korea. Among 65 amikacin-resistant isolates screened from 864 Gram-negative bacilli (GNB), 16S rRNA methylase genes were detected from 49 isolates, including Acinetobacter baumannii (43), Klebsiella pneumoniae (2), Proteus mirabilis (2) and Serratia marcescens (1), Empedobacter brevis (1). All of the 16S rRNA methylase genotype was armA and no variant sequences of amplified PCR products for armA were noted. The 16S rRNA methylase producing bacteria showed much higher resistance to aminoglycoside for Enterobacteriaceae and glucose non-fermenting (NF)-GNB and to imipenem for glucose NF-GNB, than the non-producing isolates. All of the 16S rRNA methylase producing Enterobacteriaceae had the extended-spectrum-${\beta}$-lactamase. In addition, two K. pneumoniae concurrently produced both plasmid-mediated AmpC ${\beta}$-lactamase and qnrB gene. All of the amikacin-resistant A. baumannii (43) co-harbored armA 16S rRNA methylase and $bla_{OXA-23}$ carbapenemase. In conclusion, 16S rRNA methylase producing bacteria were very prevalent among GNB in South Korea, and were commonly associated with co-resistance, including carbapenem and quinolone.

• Food Science of Animal Resources
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• v.40 no.4
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• pp.578-587
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• 2020

Clostridioides (Clostridium) difficile is a Gram (+), anaerobic, spore forming, rod shaped bacterium that can produce toxin. The objective of this study is to reveal the presence of C. difficile in meat products, to analyze the ribotype diversity by PCR and to evaluate the antibiotic susceptibility of isolated strains. The organism was isolated in 22 out of 319 (6.9%) examined meat product samples and 9 out of 22 (40.9%) isolates were identified as RT027 and all isolates had the ability of toxin production. In terms of antibiotic susceptibility, all isolates were susceptive to amoxicillin-clavulanic acid, tetracycline and vancomycin and 21 (95.4%) isolates to metronidazole. On the other hand, imipenem and cefotaxim resistance was observed in all. In conclusion, the results of this comprehensive study conducted in Turkey deduced the presence of C. difficile in different meat products. Therefore, these products can be evaluated as a potential contamination source of C. difficile from animals to humans especially for elders, youngsters, long terms wide spectrum antibiotic used and immuno-suppressed individuals.

• Tuberculosis and Respiratory Diseases
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• v.69 no.3
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• pp.201-206
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• 2010

Nontuberculous mycobacterial (NTM) diseases are increasing worldwide. However NTM lung disease in organ transplant recipients has been rarely reported. Here, we report 2 cases of NTM lung disease in heart transplant recipients. A 37-year-old man, who had undergone a heart transplant one year previous, was admitted to hospital due to a cough. Chest CT scan showed multiple centrilobular nodules in both lower lungs. In his sputum, M. abscessus was repeatedly identified by rpoB gene analysis. The patient improved after treatment with clarithromycin, imipenem, and amikacin. An additional patient, a 53-year-old woman who had undergone a heart transplant 4 years prior and who suffered from bronchiectasis, was admitted because of purulent sputum. The patient's chest CT scan revealed aggravated bronchiectasis; M. intracellulare was isolated repeatedly in her sputum. Treatment was successfully completed with clarithromycin, ethambutol, and ciprofloxacin. NTM lung disease should be considered as a potential opportunistic infection in organ transplant recipients.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.238-238
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• 1996

각종 동물 및 인체 신장 유래 DHP-I에 의한 DA-1131, imipenem(IPM) 및 meropenem(MEPM)의 속도 상수를 측정한 결과, DA-1131은 동물종에 관계없이 가장 안정성이 큰 결과를 나타내었고, 인체 DHP-I에 대한 Vmax/Km 값이 IPM의 21.9%로 관찰되어 IPM보다 하위 기질인 것으로 확인되었다. DA-1131, IPM/CS 및 MEPM/CS의 20mg/kg투여 후의 혈중농도 반감기(T$_{1}$2/)는 각각 11.4분, 8.9분, 10.3분이었으며, 1$\mu\textrm{g}$/$m\ell$ 이상의 혈중농도룰 유지하는 시간은 66.6 분, 55.9 분, 63.1 분이었다. DA-1131, DA-l131/CS, IPM/CS, MEPM 및 MEPM/CS의 40 mg/kg 투여 후 24시간 동안의 뇨중 배설율은 57.9 %, 61.3%, 22.6 %, 11.3% 및 65.9%이었으며, 각 약물을 40 mg/kg 투여 15분 후 DA-ll3l의 폐중 농도는 11.2$\mu\textrm{g}$/g으로 DA-l131/CS, IPM/CS 및 MEPM/CS와 비슷한 결과를 나타내었으며 T/P ratio도 DA-1131, DA-l131/CS, IPM/CS 와 MEPM/CS 투여군에서 거의 동일한 것으로 확인되었다. 신장중 농도는 DA-1131 과 DA-l131/CS의 경우 29.l$\mu\textrm{g}$/g 및 34.2$\mu\textrm{g}$/g으로 큰 차이를 나타내지 않았으나, IPM/CS, MEPM 및 MEPM/CS 투여군에 비하여는 높은 결과로 나타났고 T/P ratio도 DA-1131과 DA-l131/CS 투여군이 IPM/CS, MEPM 및 MEPM/CS 투여군보다 놓은 것으로 확인되었다.

• Childhood Kidney Diseases
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• v.10 no.2
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• pp.182-191
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• 2006

Purpose : We studied the degree of changes in antibiotic sensitivity toward causative organisms, prevalence and clinical manifestations of extended-spectrum $\beta$-lactamase(ESBL)-producers of urinary tract infection(UTI) for a period of three years. This serves to provide useful information in selecting adequate drugs for the treatment of UTI. Methods : We recruited 137 patients who grew more than $10^5$ CFU/mL in their urine culture among 250 patients who visited and were admitted to Handong University's Sunlin Hospital for UTI treatment from January 2003 to December 2005. We retrospectively analyzed the data from the medical records. Results : The common pathogenic organisms were Escherichia coli(65.0%), Klepsiella pneumoniae(14.0%), Enterococcus faecalis(5.8%) and Proteus vulgaris(2.9%) in consecutive order. The prevalence of ESBL-producers among isolated E. coli and K. pneumoniae was 4.5%(4 cases) and 14.3%(2 cases), respectively. The antibiotic sensitivity rates of E. coli were relatively high to amikacin(100%), imipenem(100%), ceftriaxone(95.5%) and tobramycin(91.4%) while relatively low to TMP/SMZ(55.4%), ampicillin/sulbactam(29.4%) and ampicillin(24.2%). Conclusion : The use of ampicillin, ampicillin/sulbactam and TMP/SMZ, which have been the first choices in the treatment of UTI, should be reconsidered due to the low sensitivity rates towards these antibiotics. Due to the high incidence and antibiotic tolerance of ESBL that might have risen from the development of new antibiotics and increased antibiotic use, it is necessary to consider changing the standard antibiotics that have been used in the treatment of UTI.

• Clinical and Experimental Pediatrics
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• v.54 no.2
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• pp.79-85
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• 2011

Purpose: We studied the differences in the antibiotic susceptibilities of the microorganisms that causeing urinary tract infections (UTI) in children to obtain useful information on appropriate drug selection for childhood UTI. Methods: We retrospectively analyzed the antibiotic susceptibilities of 429 microorganisms isolated from 900 patients diagnosed with UTI in the Department of Pediatrics, Chungbuk National University Hospital, from 2003 to 2008. Results: The most common causative microorganisms for UTI were Escherichia coli (81.4%), Klebsiella pneumoniae (8.4%), Enterobacter spp. (1.7%), and Proteus spp. (0.4%). E. coli showed relatively high susceptibility as compared to imipenem (100%), amikacin (97.7%), aztreonam (97.9%), cefepime (97.7%), and ceftriaxone (97.1%), while it showed relatively low susceptibility to gentamicin (GM) (79.0%), trimethoprim/sulfamethoxazole (TMP/SMX) (68.7%), ampicillin/sulbactam (33.0%), and ampicillin (AMP) (28.6%). There were no significant differences in the image findings for causative microorganisms. Conclusion: Gram-negative organisms showed high susceptibility to amikacin and third-generation cephalosporins, and low susceptibility to AMP, GM, and TMP/SMX. Therefore, the use of AMP or TMP/SMX as the first choice in empirical and prophylactic treatment of childhood UTI in Korea should be reconsidered and investigated further.

• Journal of Microbiology and Biotechnology
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• v.25 no.7
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• pp.1154-1162
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• 2015

The emergence of carbapenem resistance among Pseudomonas aeruginosa is an increasing problem in many parts of the world. In particular, metallo-$\beta$-lactamases (MBLs) and AmpC $\beta$lactamases are responsible for high-level resistance to carbapenem and cephalosporin. We studied the diversity and frequency of $\beta$-lactamases and characterized chromosomal AmpC $\beta$lactamase from carbapenem-resistant P. aeruginosa isolates. Sixty-one carbapenem-resistant P. aeruginosa isolates were collected from patients in a tertiary hospital in Daejeon, Korea, from January 2011 to June 2014. Minimum inhibitory concentrations (MICs) of four antimicrobial agents were determined using the agar-dilution method. Polymerase chain reaction and sequencing were used to identify the various $\beta$-lactamase genes, class 1 integrons, and chromosomally encoded and plasmid-mediated ampC genes. In addition, the epidemiological relationship was investigated by multilocus sequence typing. Among 61 carbapenem-resistant P. aeruginosa isolates, 25 isolates (41.0%) were MBL producers. Additionally, 30 isolates producing PDC (Pseudomonas-derived cephalosporinase)-2 were highly resistant to ceftazidime (MIC₅₀ = $256{\mu}g/ml$) and cefepime (MIC₅₀ = $256{\mu}g/ml$). Of all the PDC variants, 25 isolates harboring MBL genes showed high levels of cephalosporin and carbapenem resistance, whereas 36 isolates that did not harbor MBL genes revealed relatively low-level resistance (ceftazidime, p < 0.001; cefepime, p < 0.001; imipenem, p = 0.003; meropenem, p < 0.001). The coexistence of MBLs and AmpC $\beta$-lactamases suggests that these may be important contributing factors for cephalosporin and carbapenem resistance. Therefore, efficient detection and intervention to control drug resistance are necessary to prevent the emergence of P. aeruginosa possessing this combination of $\beta$-lactamases.

• YAKHAK HOEJI
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• v.41 no.2
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• pp.233-240
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• 1997

The in vitro antibacterial activity of DWP20418 (1R, 5S, 6S)-6-[1-(R)-Hydroxyethyl)-l-methyl-2-[(2S,4S)-2-(piperazinylcarbonyl)-1-(R)-hydroxyethyl)pyrrolidine-4-thio]carb apen-2-em-3-carboxylic acid), a new carbapenem antibiotic, was compared with those of imipenem (IPM) and meropenem (MEPM). DWP20418 was comparable or slightly more superior to MEPM against gram-positive bacteria, and it showed more potent activity to IPM against gram-negative bacteria. DWP20418 was particularly active against MRSA, and its $MIC_{90}$ of methicillin-susceptible S. aureus, low methicillin-resistant S. aureus and high methicillin-resistant S. aureus were 0.391, 25 and 50 ${\mu}g/ml$, respectively. With a view of $MIC_{90}$, DWP20418 was comparable than the other carbapenems against P. aeruginosa and E. coli isolates. The activity of DWP20418 was not affected in the presence of $Mg^{2+},\;Ca^{2+}$ or horse serum. But inoculum size and alterations in pH of medium affected its antibacterial activity. DWP20418 showed rapidly bactericidal activity within 1h, and regrowth was not observed even incubation of 24hrs at the concentrations near the MIC.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.564-572
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• 2016

In this study, we isolated and characterized Escherichia coli from mussels and inland pollution sources in or in proximity to the Changseon area on the southern coast of Korea in 2014. A total of 147 strains of E. coli were isolated from 54 mussels and 32 pollution-source samples. The susceptibility of the isolates to 24 antimicrobial agents was analyzed. The resistance of E. coli isolates to rifampin was highest at 100%, followed by cephalothin (98.6%), tetracycline (91.8%), amikacin (81.0%), ampicillin (79.6%), cefazolin (79.6%), streptomycin (73.5%), piperacillin (70.7%), gentamicin (37.4%), cefoxitin (35.4%), cefamandole (34.7%), tobramycin (29.9%), amoxicillin/clavulanic acid (24.5%), nalidixic acid (21.8%), trimethoprim (19.0%), chloramphenicol (17.7%), cefotaxime (12.9%), trimethoprim (10.9%), ceftazidime (10.2%), aztreonam (7.5%), imipenem (2.7%), cefepime (2.0%), and cefotetan (0.0%). In addition, the antimicrobial resistance of E. coli isolates from inland pollution sources was slightly greater than or similar to that of isolates from mussels.