• Journal of Yeungnam Medical Science
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• v.10 no.1
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• pp.135-143
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• 1993

The susceptibilities of 45 clinical isolates of bacteroides frogilis to cefaclor, ciproflxacin and imipenem were determined by new method, E-test (AB Bidisk, Solna, Sweden) and were compared with those from conventional agar dilution method by using brain heart infusion, Mueller-Hinton and Wilkins Chalgren agar plates. And the susceptibility of 60 clinical isolates of Bacteroides fragilis group (B. fragilis 45 strains, B. distasonis 6 strains, B. ovatus 5 strains, B. thetaiotaomicron 4 strains) to 5 quinolones (ciprofloxacin, enoxacin, norfloxacin, ofloxacin, pefloxacin) were determined by in vitro agar dilution method. Compared with agar dilution MICs for B. fragilis 45 strains, 90.3% of E-test MICs were within ${\pm}$1 dilution of the agar dilutions, and 98.4% were within 2 dilutions. And there were little effect of different medium bases to determine MICs except Mueller-Hinton agar. On Mueller-Hinton agar, B. fragilis showed have or no growth activity. In vitro susceptibility of B. fragjlis group to quinolones, most of the test strains showed resistant patterns to quinolones except ofloxacin and there was little difference of susceptibility patterns between species of B. fragilis group.

• Journal of Veterinary Clinics
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• v.21 no.1
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• pp.15-19
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• 2004

The emergence of bacterial resistance to antibiotics during therapy is a matter of great problem in clinical medicine. This may be because many veterinarians have used inappropriate antibiotics without bacteriological culture. Therefore, the purpose of this study is to determine isolation of anaerobic bacteria as pathogens from veterinary clinical specimens as well as susceptibility pattern for choosing antibiotics. Various anaerobic bacteria were isolated from clinical specimens of dogs, cats, rabbits at Veterinary Medical Teaching Hospital of Seoul National University from May 2001 to October 2002. The total number of isolated anaerobic bacteria was 13 isolates; Bacteroides spp. (3 isolates), Fusobacterium spp. (2 isolates), Peptostreptococcus spp. (2 isolates), Porphyromonas gingivalis (2 isolates), Prevotella spp. (3 isolates), and Propionibacterium acnes (1 isolate). For evaluating the antibiotic susceptibility patterns of the isolates disk diffusion method was used. All isolates were susceptable to all tested antibiotics except only one Fusobacterium varium was resistant to norfloxacin.

• Journal of Food Hygiene and Safety
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• v.23 no.4
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• pp.324-329
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• 2008

An analytical method for the simultaneous determination of nine quinolones (QNs) namely, marbofloxacin, norfloxacin(IS), ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, and flumequine in flatfish and egg was developed and validated using liquid chromatography with fluorescence detection (LC-FD). The samples were extracted using a traditional liquid-liquid extraction process; deproteinization was accomplished by the addition of trichloroacetic acid and acetonitrile (ACN), and defatting was performed with hexane. Chromatographic separation was achieved on a reverse phase C8 column with gradient elution using a mobile phase of 200 mM ammonium acetate buffer (pH 4.5) and ACN. The proposed method was validated according to the CODEX guideline. Mean recoveries of QNs from flatfish and egg were 89.6-106.5% with relative standard deviations (RSDs) below 15% at three different concentrations of 50, 100 and $500{\mu}g/kg$. Linearity was obtained with a correlation coefficient ($r^2$) of 0.9989-1.0000. The LOD for the investigated QNs was $1-16{\mu}g/kg$ depending on flatfish and egg. The present method can be applied simultaneously to determine QNs in muscle of flatfish and egg.

• Korean Journal of Veterinary Research
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• v.40 no.4
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• pp.763-767
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• 2000

This study was performed to isolate and identify bacteria from uterus with pyometra and examine their susceptibility to antimicrobial agents. Uterus of 16 bitches with pyometra were surgically removed by ovariohysteroctomy and then bacteria were isolated and identified. Also, susceptibility test to 15 antimicrobial agents was performed. Out of 16 bitches, 11 strains of Escherichia coli, 2 strains of Serratia marcescens, and 1 strain of Staphylococcus aureus and Salmonella spp. were identified. In antimicrobial susceptibility test, the majority of isolates were susceptible to enrofloxacin, norfloxacin, chloramphenicol, nalidixic acid, gentamicin, trimethprim-sulfamethazole, tetracycline, and moderately susceptible to carbenicillin, amikacin, ampicillin, neomycin, but resistant to vancomycin, streptomycin, bacitracin and colistin. In conclusion, E coli was the most common bacteria isolated from bitches with pyometra and those susceptible antimicrobial agents could be recommended to medical therapy of pyometra.

• Journal of Embryo Transfer
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• v.25 no.4
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• pp.267-272
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• 2010

The present study was to investigate the source of contamination during semen processing for in vitro uses. In the present study, frozen semen was prepared from liquid semen in our laboratory for in vitro fertilization (IVF) experiments due to lack of fresh semen. Antibiotics were added in the frozen semen extender (kanamycin and gentamicin) and in vitro culture (IVC) medium (gentamicin) for further inhibiting growth of microorganisms. Nevertheless, proliferations of microorganisms were observed in IVC culture drop during culturing of IVF embryos using frozen semen. Randomly 3 samples were taken from the liquid semen, frozen semen and egg yolk. Contaminated IVC medium, frozen-thawed semen, liquid semen and egg yolk were cultured in de Man, Rogosa and Sharpe (MRS) agar medium. Whitish colonies were detected in contaminated IVC drop, frozen-thawed semen samples and egg yolk but no colonies were formed in liquid semen samples. Gram-negative and rod-shaped identical bacteria were found in both frozen-thawed semen sample and contaminated IVC drop and egg yolk samples. Enterobacter cloacae were confirmed by API 20E kit according to manufacturer's instruction with identification value (% ID) 94.3% and T index 0.88. Antibiotic susceptibility tests were done according to Clinical and Laboratory Standards Institute (CLSI) by using ampicillin, amikacin, cephalothin, gentamicin, kanamycin, tetracycline, oxytetracycline, sulfamethoxazole trimethoprim, norfloxacin and ciprofloxacin test. Among them Enterobacter cloacae were resistant to ampicillin, amikacin, cephalothin, gentamicin, kanamycin but susceptible to tetracycline, oxytetracycline, sulfamethoxazole trimethoprim, norfloxacin and ciprofloxacin. From these findings it could be suggested that this contamination sources might be from egg yolk.

• Journal of the Korean Chemical Society
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• v.52 no.1
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• pp.30-35
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• 2008

purpose of the study was to synthesize new series of 5-cyano substituted pyrimidine analogues with different substitutions at N1 and 6 positions and to evaluate them for antibacterial and antifungal activities. The desired compounds were synthesized by tertiary condensation of ethylcyanoacetate, substituted thioureas and suitable aldehyde in presence of potassium carbonate using MORE technique. The antibacterial and antifungal activities were evaluated by cup plate method in the concentration of 25 mg. The zone of inhibition was measured in mm. All the compounds have shown significant antibacterial and antifungal activities. The maximum activity was shown by P1 and P5 against S.aureus and E.coli respectively, while P6 has shown significant activity against all types of microorganisms. The compound P8 has been found to be significantly effective against C. albicans. Norfloxacin and griseofulvin were used as standards to compare the activites of synthesized compounds. It is concluded that analogues containing p-hydroxy, p-methoxy substituted phenyl moiety at 6 position have been found to be more potent against gram-positive microorganisms, while analogues lacking these substituents on phenyl moiety possessed gram-negative activity. The compounds having p-dimethylamino substituent on phenyl moiety at 6 positions have shown moderate activity. Further, only fluorine containing analogue at N1 position was found to possess appreciable antifungal activity. This suggests that electron donating substituent on aryl moiety as well as electron withdrawing substituent at N1 plays important role in determining potency of the compounds.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.3
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• pp.294-300
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• 2019

To investigate the inhibition effect on pathogenic microbes and the antimicrobial resistance of probiotics, a total of 140 probiotics were isolated from 35 kinds of Korean commercially available Kimchi. Of those, L. plantarum was identified from 53 strains (37.9%), E. faecium from 27 strains (19.3%), and L. rhamnosus from 7 strains (5.0%) using 16S rRNA gene sequencing. Sixty nine strains (49.3%) showed overall antimicrobial activity against pathogenic microbes, namely S. Typhi, S. Enteritidis, E. coli O157:H7, S. flexneri, NAG Vibrio, Listeria monocytogenesis, Y. enterocolitica, S. aureus, S. pyogenes, G. vaginalis, C. albicans, and P. acne. The proportions of L. plantarum, E. faecium, and L. rhamnosus strains to pathogenic microbes were 75.5%, 40.7%, and 28.6%, respectively. In addition, a resistance test with 18 antimicrobial agents using a disk diffusion assay revealed a resistance incidence of 98.6% for nalidixic acid, 83.6% for streptomycin, 75.7% for gentamicin 73.6% for vancomycin, 72.1% for norfloxacin, and 67.9% for ciprofloxacin. In conclusion, L. plantarum, L. sakei, and E. faecium strains with various antimicrobial activities and broad antibiotic resistance are useful for treating diarrhea in long-term inpatients and for the alternative use for treating Candida species female vaginitis.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.671-676
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• 1998

Five hundred and seventy clinical strains of Pseudomonas aeruginosa were isolated from August 1993 to August 1994 in Korea and screened for their resistance to ciprofloxacin, norfloxacin, and ofloxacin. Among these, two P. aeruginosa strains (PA150 and PA300) were selected based on their strong resistance (MICs > 50mcg/ml) to all three quinolones. The susceptible strain as well as two resistant strains had proton gradient-dependent efflux system. Efflux system in PA300 showed different specificities to ofloxacin and ciprofloxacin while PA150 had less permeability for ofloxacin. Ofloxacin had a less inhibitory action on DNA synthesis in permeabilized cells of PA150 and PA300 than 1771M. When quinolone resistance determining region (QRDR) in gyrA was sequenced, PA300 had one missense mutation, Asn 116Tyr, which was newly reported in this work. The results showed that PA150 became ofloxacin resistant by reduced ofloxacin accumulation due to the existence of efflux system and low permeability, while resistance of PA300 was due to the efflux system and a mutation in QRDR of gyrA -the target site of quinolone.

• Korean Journal of Veterinary Research
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• v.49 no.3
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• pp.195-200
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• 2009

Avian pathogenic Escherichia coli (APEC) is an important bacterial pathogen of chickens and causes colibacillosis such as airsacculitis, perihepatitis, omphalitis, peritonitis, salpingitis, and pericarditis. As the transfer of antibiotic resistance from animal to humans can be possible, surveillance on antibiotic resistance of APEC is very important. A total 34 APEC isolates from diseased chickens during the period from 2007 to 2009 were obtained. The susceptibility of the isolates to 13 antibiotics was determined by disc diffusion assay. Resistance to erythromycin was found in 97.1% of APEC isolated, followed by resistance to tetracycline (85.3%), doxycycline (82.3%), ampicillin (73.5%), sulfisoxazole (67.6%), enrofloxacin (67.6%), ciprofloxacin (64.7%), norfloxacin (61.7%) trimethoprim/sulfamethoxazole (52.9%), gentamycin (26.5%), amoxicillin (8.8%), colistin (5.9%), and amikacin (2.9%). The blaTEM genes were detected in 25 (100%) of the 25 ampicillin-resistant APEC isolates. Among the 29 tetracycline-resistant APEC isolates, tetA and tetB genes were detected in 18 (62.1%) and 9 (31%) isolates, respectively. Twenty six (76.5%) isolates were multiresistant to at least 6 antibiotics and seven (20.1%) isolates were multiresistant to at least 10 antibiotics. This results indicated that multiple antibiotic-resistant APEC is widespread in chicken flocks in Korea.

• Biomolecules & Therapeutics
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• v.6 no.1
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• pp.63-72
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• 1998

-4-Quinolone antibiotics (pefloxacin, ciprofloxacin, norfoxacin, ofloxacin and enoxacin) were tested for mutagenicity in Salmonella typhimurium TA98, TA100, TA1535, TA1537, TA1538 and TA102, for chromosomal aberrations in cultured Chinese hamster lung (CHL) cells, and for wing somatic mutations and recombinations (wing spot) in Drosophila. Five 4-quinolones did not show any mutagenicity in Salmonella typhimurium TA98, TA100, TA1535, TA1537 and TA1538. However, they were mutagenic inSalmonella typhimurium TA102 with and without metabolic activation in both plate incorporation method and preincubation method. Ciprofloxacin induced structural chromosome aberrations in CHL cells both with and without metabolic activation, and the frequencies were 6% and up to 28%, respectively. Pefloxacin showed equivocal evidence, however, norfloxacin, ofloxacin and enoxacin did not induce the structural chromosome aberrations both in the presence and absence of metabolic activation. In the wing spot assay in Drosophila, ofloxacin increased the frequency of small single spots significantly in a dose-dependent manner but there was no dose-dependent increase of single or twin spots in the others.