• Pediatric Infection and Vaccine
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• v.17 no.1
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• pp.30-35
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• 2010

Purpose : We investigated the causative organism and its antibiotic susceptibility of community acquired urinary tract infection (UTI) in children at a secondary hospital to test the adequacy of the current guidelines. Methods : Children diagnosed with UTI at the Department of Pediatrics, Kwandong University MyMyongji Hospital by pyuria and bacterial growth of greater than $1.0{\times}10^5CFU/mL$ on clean catch midstream urine from January 2005 to December 2008 were studied retrospectively. The epidemiologic data, causative organism, and the antibiotic susceptibility were analyzed. Results : Sixty two children were diagnosed with sixty four cases of UTI's. Two bacteria were isolated in one case and thus data on 65 urine cultures were analyzed. The male:female ratio was 1.6:1 and 78.1% were less than 12 months of age. Escherichia coli was the predominant cause consisting of 53 cases (82.8%) of the cases. K. pneumoniae (5), Enterobacter (4), Enterococcus (1), $\beta$-streptococcus (1), Diphtheroides (1) were isolated. The antibiotic resistance of E. coli were as follows; ampicillin 69.8%, cefotaxime 1.9%, gentamicin 15.1%, amikacin 0.0%, levofloxacin 1.9%, and trimethoprim/sulfamethoxazole 26.4 %. Only one case of the E. coli was extended spectrum $\beta$-lactamase (ESBL) positive. Conclusion : Compared to prior reports from other tertiary hospitals in Korea, E. coli was the predominant cause in childhood UTI and the rate of ESBL positivity was low. The antibiotic resistance was also different compared to prior reports. We conclude that a difference in the cause and antibiotic resistance of childhood UTI exists between centers and this should be taken into consideration when prescribing antibiotics for childhood UTIs.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.361-369
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• 2000

Enterococcus is a normal inhabitant of the human oral cavity, the vagina, and the gastrointestinal tract. Four isolates of Enterococcus in this study were identified as E. durans. These bacteria were characterized and the interaction of these bacteria with the important oral bacteria as like S. mutans and S. oralis was studied as follows. 1. The carbohydrate fermentation test and biochemical test showed similar results in 4 isolates. 2. The susceptibility test against erythromycin, penicillin, tobramycin, ampicillin, teicoplanin, ciprofloxacin, vancomycin, gentamicin, kanamycin, and streptomycin showed to be susceptible in all four isolates. 3. The optical density of absorbance at 550 nm was 1.405 in the culture of S. mutans in disposable cuvette, whereas being 0.855, 0.867, 0.797, and 1.083 in the combined culture of S. mutans and each E. durans. 4. The mean weight of produced artificial plaque on the wires in the beaker was $1566{\pm}103mg$ in culture of S. mutans only, whereas being reduced to $44{\pm}5mg,\;41{\pm}12mg,\;34{\pm}7mg,\;and\;38{\pm}12mg$ in the combined culture of S. mutans and each E. durans. The viable cells were $2.0\times10^9$ per ml in the culture of S. mutans wheras being $2.0\times10^7\;to\;6.0\times10^7$ per ml in the combined culture S. mutans and E. durans. 5. The viable cells were $2.1\times10^8$ per ml in the culture of S. oralis, wheras being $1.4\times10^7\;to\;7.0\times10^7$ per ml in the combined culture of S. oralis and E. durans. 6. Plasmid of about 60 kb was isolated in three isolates of E. durans. These results suggested that E. durans isolated from the oral cavity inhibited the replication of S. mutans and formation of artificial plaque, while inhibiting the replication of S. oralis a little.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.4
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• pp.528-533
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• 2008

Staphylococcus aureus is a pathogene of major concern in livestock products. This study was conducted to test imported and domestic meat sold by retail stores for the presence S. aureus. In addition, the antibiotic susceptibility of any S. aureus found was also evaluated. The overall isolation rate of S. aureus was 20.2% (13.9% in pork and 33.8% in beef) in retail meats. The percentage of imported meats found to contain S. aureus (33.3% in pork and 40.4% in beef) was higher than that of domestic meat (13.0% in pork and 14.7% in beef). In addition, the detection rate of S. aureus was higher in raw material meat than in ready to cook packaged meat. When the antibiotic susceptibility of S. aureus isolated from the meat products was evaluated, ampicillin was found to be the highest (76.5%), followed by penicillin (75.3%), tetracycline (27.1%) and erythromycin (21.2%). Penicillin and tetracycline resistant were detected in 55.6% and 13.3% of the beef isolates, respectively, and 97.5% and 42.5% of the pork isolates, respectively. The tetracycline and erythromycin resistant plasmids of the isolated strain were transferred into S. aureus DPRMM2429 by the filter mating method and the frequencies of transfer was found to be $1.1{\times}10^{-5}{\sim}1.9{\times}10^{-9}$ and $1.2{\times}10^{-5}{\sim}4.0{\times}10^{-8}$ respectively.

• Biomedical Science Letters
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• v.3 no.1
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• pp.55-67
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• 1997

Considering many problems caused by the abuse of antibiotics recently, the appearance of antibiotic resistance bacteria is believed to help the cure of patients greatly. From Jan. 1st, 1996 to Dec. 31, 1996, 6135 strains were examined after being asked of and seperated from the clinical pathology departments of general hospitals, and the isolation frequency of identified bacteria and the susceptibility of antibiotics showed the following result. 1. The isolation frequency of strains was Escherichia coli, 1134 strains (18.4%), Pseudomonas aeruginosa, 856 strains (13.9%), coagulase negative Staphylococcus, 793 strains (12.89%), Staphylococcus aureus, 555 strains (9.02%), B. cepacia, 421 strains (6.84%), Enterobacter cloacae, 366 strains (5.95%), Enterobacter faecalis (4.86%), and Klebsiella pneumonia, 220 strains (3.85%). 2. The isolation rate of specimen was urine, 1, 969 strains, wound 1, 104 strains, sputum 701 strains, blood 643 strains, vaginal swab, 342 strains, and eye discharge, 192 strains, 40% of urine strains were E. coli 18％ of wound strains were B. cepacia, 43.7％ of sputum were P. aeruginosa, and in blood strains there were Enterobacter cloacae (25.8%), coagulase negative Staphylococcus (19.6%), and P. aeruginosa (8.7%). 3. The result of antibiotics susceptibility showed that, among gram negative bacilli, P. aeruginoas had resistance in almost all antibiotics except ceftazidme imipenem. But B. cepacia, the same glucose non-fermentation gram negative bacilli had more than 90％ of sensitivity in aztreonam, ceftazidime, ciproflxacin, piperacillin, trimethoprim/sulfa and had resistance in the others. Enterococcus faecalis showed more than 85% of sensitivity in penicillin-G, ampicillin, ciprofloxacin. 4. In the case of specimen antibiotics susceptibility, Enterobacter cloacae was lower in specimen isolated from blood than in those isolated from others and p. aeruginosa was low in specimen isolated from urine, which showed that there was difference in specimen antibiotics susceptibility. The result of this study shows that there happen many resisitances in antibiotics used frequently and some countermeasure is necessary because many bacteria began to show new resistance. Also it is desirable that the choice of antibiotics for infection diagnosis and its cure should be made after the inspection of antibiotics.

• Analytical Science and Technology
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• v.25 no.4
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• pp.257-264
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• 2012

Penicillins belong to the ${\beta}$-lactam class of antibiotics, and are frequently used in human and veterinary medicine. Despite the positive effects of these drugs, improper use of penicillins poses a potential health risk to consumers. This study has been undertaken to determinate multi-residues of penicillins, including amoxicillin, ampicillin, oxacillin, bezylpenicillin, cloxacillin, dicloxacillin, and nafcillin, using liquid chromatographic tandem mass spectrometer (LC-MS/MS). The developed method was validated for specificity, precision, recovery, and linearity in livestock and marine products. The analytes were extracted with 80% acetonitrile and clean-up by a single reversed-phase solid-phase extraction step. Six penicillins presented recoveries higher than 76% with the exception of Amoxicillin. Relative standard deviations (RSDs) were not more than 10%. The method was applied to 225 real samples. Benzylpenicillin was detected in 12 livestock products and 7 marine products. Amoxicillin, ampicillin, cloxacilllin, dicloxacillin, nafcillin and oxacillin were not detected. The detected levels were 0.001~0.009 mg/kg in livestock products excluding eggs and milk. In marine products, the detected levels were under 0.03 mg/kg. They were under the MRL levels. As monitoring results, it is identified to be safe but it is considered that safety management of antibiotics should continue by monitoring.

• Pediatric Infection and Vaccine
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• v.7 no.2
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• pp.233-239
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• 2000

Purpose : A great deal of youngsters suffer from otitis media, for which antimicrobials are frequently prescribed. Increased antimicrobial resistance forces physicians to judiciously use antimicrobial agents in treating patients with acute otitis media. There have however been few references with regard to otitis media in Korean children, and authors proceeded investigation to look for the causative agents of otitis media in Korean children and their antimicrobial susceptibility. Methods : The study included 65 patients younger than 15 years old who had been cared at the department of pediatrics and otolaryngology in Hanyang University Hospital from July 1994 to June 1999, and diagnosed of otitis media with otorrhea which contained microorganisms isolated in otorrhea culture. The medical records were reviewed for demographic data, isolated organisms and their antimicrobial susceptibility. Results : Among 65 patients, 37(57%) were boys and 28(43%) girls. Distribution of the patients was reciprocal to the age of the patients; 27 patients(41.5%) were younger than 1 year old, 24(36.9%) were 1 to 3 years old with the average of 2.9 years of age. Staphylococus aureus was isolated in 32 patients(49.2%), Streptococcus pneumoniae in 19 patients(29.2%) Haemophilus influenzae in 9 patients(13.8%), Streptococcus oralis in 3 patients(4.6%), Moraxella catarrhalis in 1 patient(1.5%). The isolated microorganisms were not different whether patients had cleft lip/palate or not. The antibiotic resistance rates of S. aureus were ${\geq}90%$ to erythromycin, imipenem, cephalothin, and clindamycin, 86.2% to oxacillin, 25% to chloramphenicol, 12.5% to trimethoprim/sulfamethoxazole(TMP/SMX), and 0% to vancomycin and teicoplanin. The antibiotic resistance rates of S. pneumoniae were 71.4% to penicillin and greater than 60% to erythromycin, tetracycline, TMP/SMX, 7.1% to chloramphenicol, and 0% to vancomycin and teicoplanin. The antibiotic resistance rates of H. influenzae were 55% to ampicillin and TMP/SMX, and 0% to chloramphenicol, ceftriaxone, aztreonam, imipenem and ciprofloxacin. Conclusion : With otorrhea culture, the causative organisms of otitis media appear to be S. aureus, S. pneumoniae and H. influenzae. The high antibiotic resistance rates of the isolated organisms should affect the choice of antibiotics in treating patients with otitis media. Prospective investigations utilizing tympanocentesis in microbiologic studies are needed.

• Pediatric Infection and Vaccine
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• v.7 no.2
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• pp.211-217
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• 2000

Purpose : Salmonellosis including typhoid fever is still prevalent in Korea. Recently it has been reported that the incidence of salmonella gastroenteritis is increasing with a reduction of typhoid fever. We studied the clinical and laboratory features of salmonellosis. Methods : We evaluated the clinical records of 83 patients with salmonellosis who had been confirmed by stool culture from 1994 to 1999. Results : Annual incidence of salmonellosis showed an increasing tendency during recent 4 years. Seasonally, summer(45.8%) was the most prevalent, followed by fall(32.5%). Male to female ratio was 1.4 : 1. In age distribution, 64 cases(77.1%) were under 5 year-old, and 18 cases(21.7%) were younger than 1 year-old. Clinical features included diarrhea(96.4%), fever(91.6%), vomiting(49.4%), bloody stool(42.1%), abdominal pain(40.1%) and tenesmus(12.0%). In serogroups, there was no group A and group B, group C, group D(including 2 cases of S.typhi) and group E were in 41.0%(34 cases), 3.6%(3 csaes), 51.8%(43cases) and 3.6%(3 cases), respectively. In Widal test, 5 cases(13.5%) and 1 case(2.7%) of group B, C and E(total 37 cases) were observed the O titer above 1 : 80 and 1 : 320, respectively. However, in 36 cases of group D, 19 cases(52.7%) and 9 cases(25.0%) were above the O titer 1 : 80 and 1 : 320, respectively. Antibiotics resistant rates to ampicillin, trimethoprim/sulfamethoxazole and chloramphenicol were 23.2%, 10.1% and 51.4%, respectively. Conclusion : Salmonellosis has become a common cause of gastroenteritis in children, especially under the pre-school age. Isolation of salmonella is neccessary for accurate diagnosis of gastroenteritis and typhoid fever. A careful attention of the use of antibiotics is needed to reduce the muilti-drug resistant strains.

• Neonatal Medicine
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• v.16 no.2
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• pp.172-181
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• 2009

Purpose: To identify trends in causative bacterial organisms for neonatal sepsis and antimicrobial susceptibilities over 10 years in one neonatal intensive care unit. Methods: We retrospectively reviewed the cases of culture-proven neonatal sepsis between January 1998 and December 2007. The 10-year period was divided into two phases (phase I, 1998-2002; phase II, 2003-2007) to distinguish the differences during the entire period. Results: Total 350 episodes of neonatal sepsis were identified in 315 neonates. The common pathogens of early-onset sepsis were S. epidermidis, S. aureus, P. aeruginosa, and E. cloacae in phase I, and S. epidermidis and E. cloacae in phase II. In cases of late-onset sepsis, coagulase negative Staphylococcus, S. aureus, and K. pneumoniae were isolated frequently in both phases. The incidence of sepsis caused by multi-drug resistant organisms decreased with strict infection control. Gram positive organisms showed 0-20% susceptibility to penicillin, ampicillin, and cefotaxime in both phases. Sensitivity to amikacin for Enterobacter spp. increased, whereas P. aeruginosa showed decreased sensitivity in phase II. Between 50% and 60% of other gram negative bacteria, except P. aeruginosa, were susceptible to cefotaxime in phase II in contrast to phase I. Greater than 80% of gram negative bacteria were sensitive to imipenem except P. aeruginosa and ciprofloxacin in both phases. Conclusion: The trend in causative microorganisms and antimicrobial susceptibilities can be used as a guideline for selection of appropriate antibiotics. A particular attention should be paid to infection control, especially to reduce sepsis caused by multi-drug resistant organisms.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.286-294
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• 2004

Between 1997 and 1998 in Korea, 56 isolates of Escherichia coli were obtained from pig suffering diarrhea. Among those, 38 isolates that showed the hemolytic activity, antimicrobial resistance, and toxin production were studied. Among 38 isolates, thirty-six isolates $(94.7\%)$ were resistant to tetracycline, 27 isolates $(71.0\%)$ were resistant to ampicillin, 26 isolates $(68.4\%)$ were resistant to chloramphenicol, and 21 isolates $(55.2\%)$ were resistant to trimethoprim, while none was resistant to aztreonam, amikacin, and norfloxacin. Among these iso­lates, 21 isolates $(55.3\%)$ were multiple drug resistant to at least four different class antimicrobial agents. Extended spectrum $\beta-lactamase$ producing isolates were not detected in the double disk synergy test. In these hemolytic Escherichia coli, heat-stable enterotoxin $(89.5\%)$ was the most prevalent toxin, followed by vero­toxins $(47.4\%),$ and then heat-labile enterotoxin $(31.6\%).$ Except 8 isolates $(21.0\%)$ which produced ST only, 12 isolates $(31.6\%)$ produced ST and LT, 13 isolates $(34.2\%)$ produced ST, VT, and VTe, and 5 isolates $(13.2\%)$ produced VT and VTe. However, none produced all 4 types of toxin, simultaneously. The predominant serotype could not be determined by the agglutination method. Sixteen isolates $(42.1\%)$ were strongly adhered to T-24 bladder cell and 17 isolates $(44.7\%)$ were to Caco-2 intestinal cell. Especially, 11 strains $(28.9\%)$ were evaluated as strongly adhesive to both T-24 cells and Caco-2 cells. Genes for toxin and the antimicrobial resistance were transferred to clinical isolates of Escherichia coli from human urine by the filter mating method. Results suggest the possibility that antimicrobial resistance and toxin can be transferred from animals to humans by direct con­tact of resistant bacteria as well as gene transfer, although there was no correlation between toxin production, adherent activity, and antimicrobial resistance among hemolytic E. coli isolated from pig suffering diarrhea.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.295-301
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• 2004

Recently, the rapid increase and global spread of extended-spectrum $\beta-lactamase$ producing clinical isolates has become a serious problem. The incidence of extended-spectrum $\beta-lactamase$ producing clinical isolates of Escherichia coli in Korea and susceptibility to antimicrobial agents were investigated. Total 233 isolates of E. coli were obtained from urine from hospitalized patients in Guro hospital, Korea University in 2001. One hun­dred and eighty four isolates $(78.9\%)$ were resistant to ampicillin, 80 isolates $(34.3\%)$ were resistant to ceph­alothin, 93 isolates $(39.9\%)$ were resistant to gentamicin, and 64 isolates $(27.5\%)$ were resistant to norfloxacin. Among 233 isolates, 17 isolates $(7.3\%)$ were positive as determined by the double disk synergy test. When min­imal inhibitory concentrations were assayed with additional 6 antimicrobial agents, 13 isolates $(76.5\%)$ were multi-drug resistant to at least four different class antimicrobial agents. Extended-spectrum $\beta-lactamase$ were characterized with isoelectric focusing gel electrophoresis and DNA sequencing. They were TEM-1 in 5 iso­lates, TEM-15 in 1 isolate, TEM-20 in 1 isolate, TEM-52 in 4 isolates, TEM-1 and AmpC in 2 isolates, TEM-1 and OXA-30 in 1 isolate, TEM-1 and OXA-33 in 1 isolate, TEM-1, CTX-M-3, and AmpC in 1 isolate, but SHV was not detected. Antimicrobial resistance genes were transferred to animal isolate of E. coli (CCARM No. 1203) by the filter mating method. Extended spectrum $\beta-lactamase$ producers studied in the current study have low correlation to each other as determined by random amplified polymorphic DNA and pulsed field gel elec­trophoresis. This is a contradictory result from the general hypothesis that extended-spectrum $\beta-lactamase$ pro­ducers in one hospital is a result from a clonal spread.