• 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.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.17 no.1
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• pp.1-15
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• 1979

Mycoplasma pneumoniae strain CL-s attached to broth-covered surfaces was examined sequentially during growth from single cells for morphologic and ultrastructural changes using several different electron microscopic techniques. Changes in morphology revealed both round and spindle shapes and observation of cell transitions suggested some type of morphological cycle. The round to-ovoid cells observed in the early stages of growth appeared to be viable, and morphologically and ultrastructurally different from the spherical fors which were produced during the latter stage of growth. The spindle segments were detected appeared to be structurally the same as the terminal cored structure seen in thin sections and may be a growing point or an attachment site of the cell. A tubular structure was observed in the core of the terminal structure and a microtubule-like element appeared to bridge between some spindle segments. A matrix sunstance was observed around single cells as well in the intercellular space of the colonies prepared by critical point metrical triple-layered cytoplasmic mermbranes, surfaces, of which appeared to be structurally different each other, were observed in young cells, whereas symmetrical and thicker membranes were seen in older cells. Small bodies were found in 4d or older cultures and did not appear to contain any internal structures or an easily detectable unit membrane.

• Clinical and Experimental Pediatrics
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• v.50 no.2
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• pp.157-162
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• 2007

Purpose : The purpose of this study was to analyze the epidemiology, causative organism, clinical manifestation and prognosis of bacterial meningitis for children after the introduction of Haemophilus influenzae type b (Hib) vaccine in Daejeon and Chungcheong area. Methods : We analyzed retrospectively 53 medical records who had been diagnosed with bacterial meningitis at 10 general or university hospitals in Daejeon and Chungcheong area. All patients aged 1 month-14 years admitted between January 2001 through December 2005. Results : During the 5-year study period, 40 of all cases were positive for bacterial growth. Of the 40 cases that were CSF culture-proven bacterial meningitis, Streptococcus peumoniae was the most common bacteria for 17 (32.1%) of all cases, followed by H. influenzae for 10 (18.9%), Neisseria meningitidis for 3 (5.7%). In this study, the most common clinical manifestation is fever, accompanied by all cases. CSF leukocyte count was more than $100/mm^3$ in 45 (84.1%) cases. CSF glucose concentration was less than 50 mg/dL in 42 (79.2%) cases and protein concentration was more than 45 mg/dL in 49 (92.5%) cases. 45 of all cases made a recovery after treatment and were discharged. Most common complication after treatment is subdural effusion (19.0%) and hearing disturbance (9.4%). Conclusion : The most common organism of culture-proven bacterial meningitis in the children beyond neonatal period was S. pneumoniae. Continued surveillance studies were demanded to know the altered incidence of bacterial meningitis, because we expect the incidence of S. pneumoniae meninigitis will be on the decrease after more active innoculation of pneumococcal protein conjugate vaccine.

• Korean Journal of Veterinary Research
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• v.42 no.1
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• pp.45-54
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• 2002

The study was carried out to characterize the pharmacokinetics after intravenous (iv, 20 mg/kg) and oral (p.o. 100 mg/kg) administration as oxytetracycline (OTC) and tiamulin (TIA) mixture in swine and to determine interaction between OTC and TIA against various pig pathogenic bacteria. The antibacterial effects of OTC in combination with TIA in vitro showed synergistic effect against Salmonella typhimurium 1925, Pasteurella multocida Type A, P. multocida Type D, Krebsiella Pneumoniae 2001, K. Pneumoniae 1560, K. Pneumoniae 2208, Haemophillus pleuropneumonia S 2, and H. pleuropneumonia S 5, but against additive effect E. coli K88ab and S. choleraesuis on the basis of fractional inhibitory concentration (FIC) index. On the while, after i.v. and p.o. administration of OTC and TIA mixture, each OTC and TIA concentrations in plasma were fitted to an open two-compartment model. After i.v. administration of OTC-TIA mixture, the mean distribution half-life ($T_{1/2{\alpha}}$) of OTC and TIA in plasma showed 0.29 h and 0.17 h, and the mean elimination half-life ($T_{1/2{\beta}}$) of those was 4.36 h and 6.64 h, respectively. The mean volume of distribution at steady state ($Vd_{ss}$) of OTC and TIA was $0.85{\ell}/kg$ and $2.44{\ell}/kg$, respectively. After oral administration of OTC and TIA mixture, the mean maximal absorption concentrations ($C_{max}$) of OTC and TIA were $0.60{\mu}g/m{\ell}$ at 1.07 h ($T_{max}$) and $1.68{\mu}g/m{\ell}$ at 1.85 h ($T_{max}$), respectively. The mean elimination half-life ($T_{1/2{\beta}}$) of those showed 6.84 h and 6.36 h. In conclusion, we could suggest in this study that the combination of OTC and TIA may be recommended for the antibacterial therapy against polymicrobial infections, and both OTC and TIA showed large distribution to tissues and high $C_{max}$ after p.o. administration.

• Journal of Microbiology
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• v.43 no.4
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• pp.337-344
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• 2005

Although pneumococcus is one of the most frequently encountered opportunistic pathogen in the world, the mechanisms responsible for its infectiveness have not yet been fully understood. In this paper, we have attempted to characterize the effects of pneumococcal transformation on the pathogenesis of the organism. We constructed three transformation-deficient pneumococcal strains, which were designated as Nos. 1d, 2d, and 22d. The construction of these altered strains was achieved via the insertion of the inactivated gene, comE, to strains 1, 2 and 22. We then conducted a comparison between the virulence of the transformation-deficient strains and that of the wild-type strains, via an evaluation of the ability of each strain to adhere to endothelial cells, and also assessed psaA mRNA expression, and the survival of hosts after bacterial challenge. Compared to what was observed with the wild-type strains, our results indicated that the ability of all of the transformation-deficient strains to adhere to the ECV304 cells had been significantly reduced (p < 0.05), the expression of psaA mRNA was reduced significantly (p < 0.05) in strains 2d and 22d, and the median survival time of mice infected with strains Id and 2d was increased significantly after intraperitoneal bacterial challenge (p < 0.05). The results of our study also clearly indicated that transformation exerts significant effects on the virulence characteristics of S. pneumoniae, although the degree to which this effect is noted appears to depend primarily on the genetic background of the bacteria.

• Pediatric Infection and Vaccine
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• v.13 no.2
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• pp.124-129
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• 2006

Purpose : We investigated the causative organisms of bacterial meningitis by age distribution from 1996 to 2005. Methods : Retrospective data were obtained from the medical records with diagnosis of bacterial meningitis or neonatal meningitis from 1996 through 2005. A case was defined by isolation of organism or detection of its antigen by latex agglutination from cerebrospinal fluid. Results : A total of 46 cases(27 neonates and 19 children) were identified. 15 of 27 episodes(55.6%) of neonatal meningitis had a concomitant-positive blood culture. Group B streptococci were the most common bacterial causes of neonatal meningitis(44.4%). Nine of 12 episodes(75.0%) were late-onset infections in neonatal meningitis caused by group B streptococci. 16 of 19 children(84.2%) with bacterial meningitis beyond the neonatal period were younger than 5 years of age(median age, 23 months). Of 19 cases, 8 infections were with Streptococcus pneumoniae, 8 were with Haemophilus influenzae and 3 were with Neisseria meningitidis. Since 2001 there was no case of meningococcal meningitis in this study. Conclusion : In neonates group B streptococci are the most common causative organisms of bacterial meningitis, especially late-onset infections. In infants and young children, the predominant causes of bacterial meningitis are H. influenzae and S. pneumoniae; meningitis caused by the former are likely to decrease after the introduction of the conjugate vaccine for H. influenzae type b.

• Clinical and Experimental Pediatrics
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• v.50 no.1
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• pp.33-39
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• 2007

Purpose : In spite of medical advances, empyema is a serious complication of pneumonia in children. Vaccination practices and antibiotic prescribing practices promote the change of clinical manifestations of empyema and causative organisms. So we made a nationwide clinical observation of 122 cases of empyema in children from 32 hospitals during the 5 year period from September 1999 to August 2004. Methods : Demographic data, and clinical information on the course and management of empyema patients were collected retrospectively from medical records in secondary and tertiary hospitals in Korea. Results : One hundred twenty two patients were enrolled from 35 hospitals. The most frequent age group was 1-3 years, accounting for 48 percent of all cases. The male to female sex ratio was 1.2:1. The main symptoms were cough, fever, respiratory difficulty, lethargy and chest pain in order of frequency. Hematologic findings on admission revealed decreased hemoglobin levels ($10.4{\pm}1.6g/dL$) and increased leukocyte counts ($16,234.3{\pm}10,601.8/{\mu}L$). Pleural fluid obtained from patients showed high leukocyte counts ($30,365.8{\pm}64,073.0/{\mu}L$), high protein levels ($522.3{\pm}1582.3g/dL$), and low glucose levels ($88.1{\pm}523.5mg/dL$). Findings from pleural fluid cultures were positive in 80 cases(65.6 percent). The most common causative agent was Streptococcus pneumoniae. The majority of patients were treated with antibiotics and closed drainage. Some patients needed open drainage (16.4 percent) or decortication (3.3 percent). The mean duration of hospitalization was $28.6{\pm}15.3days$. Conclusion : We analyzed childhood empyema patients during a period of 5 years in Korean children. The most frequent age group was 1-3 years and the most common causative agent was Streptococcus pneumoniaeiae. The majority of patients were treated with antibiotics and close drainage.

• Fashion & Textile Research Journal
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• v.5 no.4
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• pp.395-398
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• 2003

In this study, we measured the antibacterial activities, deodorization, UV cut ability, whiteness and SEM, according to the size($5{\mu}m$, $15{\mu}m$) of $TiO_2$, concentration(3%, 5%, 10%) and dipping temperature($50^{\circ}C$, $70^{\circ}C$) with using anatase type of $TiO_2$ photocatalyst. Photocatalyst is the substance which carries out functions, such as decomposition, removal, deodorization, antibacterial, etc. of a contaminant, in a place with light based on an oxidation-reduction reaction. The results of this study were as follow. Antibacterial activities are increased with increasing of the $TiO_2$'s concentration, and $TiO_2$ has high antibacterial activities for Staphylococcus aureus but it has low antibacterial activities for Klebsiella pneumoniae. The deodorization and UV cut ability is very good, therefore be able to get good effects with using only 3% of $TiO_2$. Every effects are increased by using small size of $TiO_2$ and high dipping temperature.

• Clinical and Experimental Pediatrics
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• v.46 no.4
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• pp.345-350
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• 2003

Purpose : Bacterial meningitis is a serious infection of childhood associated with a significant morbidity and mortality. Repeated cerebrospinal fluid(CSF) examination is a useful prognostic indicator and a delayed sterilization is associated with a higher incidence of neurologic abnormalities. In this study we tried to determine the prognostic value of repeated CSF latex agglutination testing. Methods : We retrospectively evaluated 19 patients admitted to Ewha Womans University Mokdong Hospital for bacterial meningitis from January 1997 to June 2002. Bacterial meningitis was confirmed by a positive CSF culture and a positive CSF latex agglutination test. Repeated CSF examinations were done at three, seven, 14, 21 and 28 days after antibiotics therapy. Neuroradiologic studies were performed. Results : The mean age was $10.6{\pm}12.3months$(range; two to 33 months). The male to female ratio was 2.8 : 1. The causative organisms were Haemophilus influenzae type b 57.9%, Group B Streptococcus 21.1%, Streptococcus pneumoniae 15.7% and Escherichia coli 5.3%. Three days after the initiation of antibiotics therapy, repeated CSF latex agglutination tests persisted as positive in nine (47.4%) out of 19 cases, but all CSF cultures became negative. In those cases with negative latex agglutination tests three days after antibiotics therapy, neuroradiologic findings were completely normal. But, in cases with positive latex agglutination tests three days after antibiotics therapy, neuroradiologic abnormalities such as cerebral infarction, encephalomalasia occurred in 44.4%. Conclusion : Repeated CSF latex agglutination testing was valuable as a prognostic factor in bacterial meningitis. Neuroradiologic abnormalities may occur in cases with delayed clearance of CSF latex agglutination tests more often than in cases with negative latex agglutination tests three days after antibiotics therapy.