• Pediatric Infection and Vaccine
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• v.10 no.2
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• pp.208-214
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• 2003

Purpose : We performed a retrospective study on bacterial meningitis in children, pertaining to the causative organisms, bacterial resistance to antibiotics and the effect of recent introduction of Haemophilus influenzae type b(Hib) vaccine. Methods : We analysed the forty-three cases of bacterial meningitis which had been treated at the Inha University Hospital from June 1996 to June 2003. Results : Nineteen cases(44.2%) of them were infants younger than 2 months of age, and 29 cases(67.5%) younger than 1 year of age. The common causative organisms under 2 months of age were group B streptococcus(GBS)(47.4%), E. coli(21.1%), and Klebsiella pneumoniae(21.1%). In the age group beyond 2 months of age, S. pneumoniae were seen in 50 %, H. influenzae in 16.7% and N. meningitidis in 16.7%. All of the five cases of Hib meningitis had not been vaccinated for Hib. There has been no Hib meningitis cases since 2001. Overall fatality rate was 4.5%, and complication occurred in 39%. Complications was significantly less frequent in patients resumed to be treated within 48 hours after onset compared to after 48 hours after onset. Penicillin resistance of S. pneumoniae and GBS isolated among bacterial meningitis cases was high. Conclusion : Timing of treatment after the onset of the disease appeared the most important factor for prognosis of bacterial meningitis. The cases of H. influenzae meningitis have decreased probably due to Hib vaccination.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.38-45
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• 2010

The study performed to identify the type of ESBL against strains which are producing extendedspectrum ${\beta}$-lactamases and isolated from sewage in Suyeong sewage disposal plant, Busan Environmental Corporation. By the standard activated sludge method, Suyeong sewage disposal plant purify living and lavatory sewage gathering from the northeast Busan and the facility purify total 550,000 tons of living sewage disposal a day. 14 strains were isolated by double disk synergy test and the third generation cepha-antibiotics test. Indole, methyl-red, Voges-Proskauer, Simmon's citrate, decarboxylasedihydrolase and sugar-fermentation tests identified as Klebsiella pneumoniae (n=4) and Escherichia coli (n=10). Plasmid-mediated transmission test against isolated 14 strains proved 11 strains transmitted resistance to recipient E. coli J53 (sodium $azide^R$, $ceftazidime^S$). 9 strains of conjugant were expressed ESBL genes transferred from parental strain but 2 conjugants did not expressed. The type of ESBL from each strain was determined by isoelectric focusing points, DNA and amino acids sequencing. The results indicated that the types of ESBL transmitted to recipient E. coli J53 were TEM-1, the parental TEM type and SHV-12 type.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.326-332
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• 2008

Various bacteria were isolated from Korean soil samples based on their capability inhibiting the growth of MRSA strains. Among them, strain YK5 with the highest activity was a Gram positive sporulative bacillus with motility. It did not produce indole and no acid was formed from mannitol by the bacterium. The 16S rRNA sequence of the strain showed $95{\sim}98%$ homology with those of Paenibacillus spp.. The bacterial isolate shared the highest homology with that of P. elgii (98%), but was named as Paenibacillus incheonensis YK5 due to differences in physiological properties. Butanol extract of the P. incheonensis YK5 culture grown in SST medium at $37^{\circ}C$ for 96 hr showed a broad antimicrobial activity against Gram-positive (MRSA and Streptococcus pneumoniae) and negative (Pseudomonas aeruginosa, Salmonella spp., Shigella spp., Escherichia coli, Klebsiella pneumoniae) pathogenic bacteria and fungi (Cryptococcus neoformans and Trichophyton). The antimicrobial activity in the crude extract was stable in a broad range of temperature and pH, $20{\sim}100^{\circ}C$ and $3.0{\sim}6.0$, respectively. Therefore, the antimicrobial activity of P. incheonesis YK5 had potential as a novel antibiotics for pathogens including 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.

• Pediatric Infection and Vaccine
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• v.28 no.2
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• pp.82-91
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• 2021

Background: The purpose of this study was to investigate the association between antibiotic use and the antimicrobial resistance of gram-negative bacteria isolated from blood cultures in a pediatric population. Methods: From January 2014 to June 2018, the antibiotic resistance pattern of Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa obtained from bacteremic patients aged ≤18 years hospitalized at Asan Medical Center Children's Hospital was analyzed and the parenteral antibiotic consumption data were retrieved. Results: During the study period, the blood culture was positive for K. pneumoniae (6.4%; 105/1,628), E. coli (5.6%; 91/1,628), P. aeruginosa (3.3%; 54/1,628), and A. baumannii (2.5%; 41/1,628), and the extended-spectrum antibiotic resistance rate of gram-negative bacteria was consistently high. The overall resistance rate of E. coli and K. pneumoniae to extendedspectrum cephalosporin was 49.3% and 54.4%, respectively. Carbapenem-resistant E. coli was first detected in 2014; its overall resistance rate to carbapenem was 5.3%. There was a linear correlation between the usage of 3rd generation cephalosporin and the resistance of A. baumannii (r²=0.96, P=0.004) and carbapenem usage and the resistance of K. pneumoniae (r²=0.79, P=0.045). Conclusions: A positive linear correlation was observed between antibiotic resistance and the corresponding antibiotic usage in 3rd generation cephalosporin resistant A. baumannii and carbapenem resistant K. pneumoniae. The judicious use of antibiotics in healthcare settings is important to minimize selection for extended-spectrum β-lactamase (ESBL) and carbapenem resistance in gram-negative bacteria.

• KSBB Journal
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• v.19 no.4
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• pp.315-320
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• 2004

We examined the culture conditions and degrading characteristics of styrene dimer (endocrine disrupter) using microorganism. The isolated microbe were consisted of 3 kinds of strain. The strains were identified to Pseudomonas sp. and Klebsiella pneumoniae by API 20E kit, but one was not identified. Single strain was not grown on the C-medium containing styrene dimer. However the complex strain YH3 could grow and we confirmed it by the broth color and O.D$_{660nm}$ (optical density 660 nm). The optimal culture conditions of complex strain YH3 were 35$^{\circ}C$, 1,000 ppm (v/v) of styrene dimer and pH 7.0, respectively. In tolerance test against the organic solvents, the complex strain YH3 could grow above log P=3.1, and could degrade ethyl benzene and 2,4-D, one kind of herbicide. As a result of TLC (Thin Layer Chromatography) analysis, we confirmed that the metabolite of styrene dimer was created by YH3 after 5th day, but not at control samples.

• Journal of Microbiology and Biotechnology
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• v.30 no.2
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• pp.271-278
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• 2020

Glycerol dehydrogenase (GlyDH) catalyzes the oxidation of glycerol to dihydroxyacetone (DHA), which is the first step in the glycerol metabolism pathway. GlyDH has attracted great interest for its potential industrial applications, since DHA is a precursor for the synthesis of many commercially valuable chemicals and various drugs. In this study, GlyDH from Klebsiella pneumoniae (KpGlyDH) was overexpressed in E. coli and purified to homogeneity for biochemical and molecular characterization. KpGlyDH exhibits an exclusive preference for NAD⁺ over NADP⁺. The enzymatic activity of KpGlyDH is maximal at pH 8.6 and pH 10.0. Of the three common polyol substrates, KpGlyDH showed the highest k_cat/K_m value for glycerol, which is three times higher than for racemic 2,3-butanediol and 32 times higher than for ethylene glycol. The k_cat value for glycerol oxidation is notably high at 87.1 ± 11.3 sec^-1. KpGlyDH was shown to exist in an equilibrium between two different oligomeric states, octamer and hexadecamer, by size-exclusion chromatography analysis. KpGlyDH is structurally thermostable, with a T_m of 83.4℃, in thermal denaturation experiment using circular dichroism spectroscopy. The biochemical and biophysical characteristics of KpGlyDH revealed in this study should provide the basis for future research on its glycerol metabolism and possible use in industrial applications.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.82-87
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• 1991

Xanthomonns curnpestris M12, Xunthornonas sp. M28, Acinetuhucter Iwofz GI, and Klebsiella pneumoniae L25, Pseudomonas rnaltophiliu N246 were screened to increase the ability for crude oil utilization. All of these could utilize hexadecane and octane with the exception of N246 strain for only octane biodegradation. Thus N246, M12, and M28, strains were specially examined for octane oxidation. Octane biodegradation by three strains showed the optimal conditions at $30^{\circ}C$, pH 7.0~9.0, and 0.2~0.3% octane concentration as a substrate. It was found that P. multofihila N246 and X. curnpestns M12 had plasmid and the cured plasmid from N246 strain lost octane uitilization. Therefore, it was confirmed that certain genes for octane utilization were Iocated on OCT plasmid in N246 strain. The size of OCT plasmid in N246 strain was 118 kb. The N246 strain was resistant to ampicillin.

• Journal of Ginseng Research
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• v.23 no.2 s.54
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• pp.67-73
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• 1999

This study carried out to scanning and select the antimicrobial pharmaceuticals which were suppress the rottening of fresh ginseng. We are isolated 20 kinds of microorganisms from rotten ginseng. In these of the microorganisms, five bacteria, fresh ginseng root-rottening, are identified to Pseudomonas putida, Pseudomonas putida biotype A, Bacillus spp, Enterobacter cloacae, and Klebsiella pneumoniae. Particularly. Bacillus spp was rapidly rotted the ginseng root, compared with the others. The antimicrobial activity were tested with 19 kinds of water extracts, and 34 kinds of essential oils. The water extract of Terminaliae Fructus, and Schiandra chinensis are strongly inhibited the growth of bacteria causing the ginseng root-rottening. And 5 kind of essential oils are inhibited bacteria. It was regarded that the water extract of Terminaliae Fructus has weekly water insoluble and polar antimicrobial components.

• The Korean Journal of Mycology
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• v.23 no.2 s.73
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• pp.176-189
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• 1995

For the development of antibiotics from Korean mushrooms, the biological activities of extracts from 98 species of mushrooms and from 25 mushrooms were tested against 9 different Gram-negative bacteria and 8 fungi, respectively. Fruiting bodies of each mushrooms were extracted with petroleum ether (P), 80% ethanol (E), and distilled water (H) in that order. P, E, or H extracts from 20 mushroom samples exhibited the antibacterial activity against 8 different Gram-negative bacteria containing Klebsiella pneumoniae, selectively. Among the mushroom extracts with antibiotic activity, E extracts of Boletus umbriniporus, Armillariella tabescens, Rhodophyllus sinuatus, and Suillus luteus showed various antibiotic activities against several bacteria. E extracts of Abortiporus biennis, Phellinus gilvus, and Polyporus dispansus are highly active against Salmonella typhi and their minimum inhibitory concentration (MIC) was all $10\;{\mu}g/ml$. E extract of Armillariella tabescens showed the antifungal activity against Trichopyton mentagrophytes, and its MIC was $300\;{\mu}g/ml$.