• The Korean Journal of Food And Nutrition
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• v.13 no.6
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• pp.611-618
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• 2000

For the purpose of the isolation of microorganisms which have the capability of nitrification, we isolated the microorganisms in 6 samples collected from the stream of Kyonggi area. 60 strains were isolated. The selected strain were identified as a Aeromonas hydrophila based on the data obtained from the morphological, biochemical and cultural characteristics defined experiments. Among them Aeromonas hydrophila (AH-1), (AH-3) , (AH-4), (AH-6) showed the highest nitrification capability. All isolates were resistant to amoxillin, ampicillin, cephalothin and ticarcillin. Optimum culture conditions of isolates were 37$^{\circ}C$ and 1${\times}$10$\^$8/ cells/ml for 4 hours in the nitrate medium.

• Korean Journal of Veterinary Research
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• v.50 no.4
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• pp.279-284
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• 2010

Combination therapy of antibiotics is leading to improved efficacy or safety profiles with decrease emergence of bacterial resistance. Because of this benefit, many of antibacterial combinations have been used in veterinary practice for the past few decades. The purpose of this study was to examine the in vitro activity of an amoxicillin alone and in combination with other antibiotics against pathogenic bacteria of fish origin. Based on the fractional inhibitory concentration (FIC) index (FIC $$\leq_-$$ 0.5), a synergistic interaction was shown in combination of florfenicol with amoxicillin or cefuroxime. The combination of florfenicol and amoxillin showed higher antibacterial activity than that of florfenicol and cefuroxime. Ratio of amoxicillin and florfenicol in combination was 1 : 1, which showed the antibacterial activity against bacterial isolates of fish as compared with other ratios. A synergetic effect of the combination (amoxicillin and florfenicol) was further confirmed in the time-kill curve study. The study showed a better in vitro antibacterial activity of a 1 : 1 combination of amoxicillin and florfenicol than the individual antibacterial against bacterial isolates of fish. In conclusion, the combination of florfenicol and amoxicillin may serve as a potential antibacterial therapy in fishes infected pathogenic bacteria.

• Clinical and Experimental Pediatrics
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• v.48 no.1
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• pp.40-47
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• 2005

Purpose : S. pneumoniae is one of major pathogens of community-acquired respiratory infections. The rate of antibiotic resistance to this organism has increased, and resistance to multiple antimicrobial agents in a single strain of S. pneumoniae may compromise the efficacy of empiric antimicrobial treatment commonly used for respiratory infections. We did this study to find out the penicillin resistant distributions and oral antibiotics susceptibility patterns against S. pneumoniae, isolated from pediatric patients with community-acquired respiratory infections in Korea. Methods : One hundred fifty six pneumococcal isolates obtained from pediatric patients with community-acquired respiratory infections such as acute otitis media(AOM), sinusitis and pneumonia between May 2000 to June 2003. And MICs of penicillin and oral antibiotics(amoxicillin, amoxicillin-clavulanate, cefaclor) were performed by broth microdilution methods according to the NCCLS(2003a). Results : Seventy eight percent of the isolates were resistant to penicillin. The isolates, collected from AOM patients showed the highest penicillin resistance(92.7%). The resistant rates of amoxicillin (16.7%) and amoxicillin-clavulanate(9.6%), based on susceptibility breakpoints established by the NCCLS, were markedly lower than these of penicillin. But, the resistant rate of cefaclor was very high, above 95%. Conclusion : We concluded that pneumococci isolated from study cases may be one of the world's highest penicillin resistant rates. But, amoxicillin and amoxicillin-clavulanate can be used as a first-line antibiotics. Finally, we hope that a continuous surveillance study to monitor resistant patterns of pneumococcal respiratory infections will be needed for the standard guidelines of empiric antibiotic treatment.

• Clinical and Experimental Pediatrics
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• v.49 no.7
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• pp.777-783
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• 2006

Purpose : Urinary tract infection(UTI) is one of the most frequent infections in children. E. coli is the most frequent etiological micropathogen in pediatric community UTI, and E. coli has developed resistance to many antibiotics, highlighting the need for regular surveys of this organism resistant patterns in the community. The aim of this study was to determine the oral antibiotic susceptibility patterns of E. coli, isolated from pediatric patients with uncomplicated community acquired UTI. Methods : E. coli isolates, obtained from pediatric patients with uncomplicated community acquired UTI between October in 2004 to September in 2005. And minimal inhibitory concentrations(MICs) of oral aminopenicillins and beta-lactamase inhibnitors(ampicillin, amoxacillin, ampicillin-sulbactam), oral cephalosporins(cefaclor, cefixime) and sulfa drug(trimethoprime-sulfamethoxazole) were performed according to the National Committee for Clinical Laboratory Standards(NCCLS) guide line. Results : Total 211 organisms were isolated from pediatric out-patients with community UTI. E. coli was the most common organism(89 percent), followed by E. fecalis, Proteus species, S. aureus, M. morganii, and P. aeruginosa. The resistant rates of aminopenicillins and beta-lactamase inhibitors, cefaclor and sulfa drug to E. coli were very high. But, the resistant rate of cefixime was markedly low, and ESBL strains were isolated with small rates. Conclusion : Our study results suggest that aminopenicillins, cefaclor and sulfa drug may not be useful as first line empirical antibiotics to treat pediatric patients with community UTI in Korea. But, 3rd generation cephalosporin such as cefixime can be used as effective second line antibiotics after primary treatment failure, also may be useful as an empirical first line antibiotic. Finally, we conclude that a continuous surveillance study to monitor susceptibility patterns of E. coli in community UTI will be needed for the standard guide lines of empirical oral antibiotic treatment.