• Clinical and Experimental Pediatrics
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• v.54 no.2
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• pp.79-85
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• 2011

Purpose: We studied the differences in the antibiotic susceptibilities of the microorganisms that causeing urinary tract infections (UTI) in children to obtain useful information on appropriate drug selection for childhood UTI. Methods: We retrospectively analyzed the antibiotic susceptibilities of 429 microorganisms isolated from 900 patients diagnosed with UTI in the Department of Pediatrics, Chungbuk National University Hospital, from 2003 to 2008. Results: The most common causative microorganisms for UTI were Escherichia coli (81.4%), Klebsiella pneumoniae (8.4%), Enterobacter spp. (1.7%), and Proteus spp. (0.4%). E. coli showed relatively high susceptibility as compared to imipenem (100%), amikacin (97.7%), aztreonam (97.9%), cefepime (97.7%), and ceftriaxone (97.1%), while it showed relatively low susceptibility to gentamicin (GM) (79.0%), trimethoprim/sulfamethoxazole (TMP/SMX) (68.7%), ampicillin/sulbactam (33.0%), and ampicillin (AMP) (28.6%). There were no significant differences in the image findings for causative microorganisms. Conclusion: Gram-negative organisms showed high susceptibility to amikacin and third-generation cephalosporins, and low susceptibility to AMP, GM, and TMP/SMX. Therefore, the use of AMP or TMP/SMX as the first choice in empirical and prophylactic treatment of childhood UTI in Korea should be reconsidered and investigated further.

• Journal of Microbiology and Biotechnology
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• v.16 no.6
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• pp.889-895
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• 2006

To investigate the antibiotic-resistant patterns and the gene types of extended-spectrum $\beta$-lactamase (ESBL)-producing Klebsiella pneumoniae, we collected 226 Klebsiella pneumoniae strains from three general hospitals with more than 500 beds in Busan, Korea from September 2004 to October 2005, The minimum inhibitory concentration (MIC) of antibiotics was measured using the Gram-negative susceptibility (GNS) cards of Vitek (Vitek system, Hazelwood Inc., MO, U.S.A.). Of the 226 K, pneumoniae isolates, 65 ESBL-producing K. pneumoniae strains were detected by the Vitek system and confirmed by the double-disk synergy test. TEM (Temoniera) type, SHV (sulfhydryl variable) type, and CTX-M (cefotaxime) type genes were detected by polymerase chain reaction. All 65 K. pneumoniae strains were resistant to ampicillin, cefazolin, cefepime, ceftriaxone, and aztreonam, and 83.0% of the organisms were resistant to ampicillin/sulbactam, 66.1% to tobramycin, 67.6% to piperacillin/tazobactam, 61.5% to ciprofloxacin, and 47.6% to trimethoprim/sulfamethoxazole, and 43.0% to gentamicin. TEM-type ESBLs (TEM-1 type, -52 type) were found in 64.6% (42 of 65) of the isolates, SHV-type ESBLs (SHV-2a type, -12 type, -28 type) in 70.7% (46 of 65) of isolates, and CTX-M-type ESBLS (CTX-M-15 type) in 45% (29 of 65) of isolates. Of the 65 ESBL-producing K. pneumoniae strains, two strains were found to harbor blaSHV-28, which were detected in Korea for the first time. Therefore, more investigation and research on SHV-28 are needed in order to prevent the ESBL type-producing K. pneumoniae from spreading resistance to oxyimino cephalosporin antibiotics.

• Journal of Applied Biological Chemistry
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• v.58 no.3
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• pp.227-232
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• 2015

A microarray study has been employed to understand changes of gene expression in E. coli KD43162 resistant to ampicillin, ampicillin-sulbactam, piperacillin, piperacillin-tazobactam, cefazolin, cefepime, aztreonam, imipenem, meropenem, gentamicin, tobramycin, ciprofloxacin, levofloxacin, moxifloxacin, fosfomycin, and trimethoprim-sulfamethoxazole except for amikacin using disk diffusion assay. Using Sodium dodecyl sulphate-polyacrylamide gel electrophoresis and MALDI-TOF MS analyses, 36 kDa of outer membrane proteins (OMPs) was found to be deleted in the multidrug resistant E. coli KD 43162. Microarray analysis was used to determine up- and down-regulated genes in relation to multidrug resistant E. coli KD43162. Among the up-regulated genes, these genes were corresponded to express the proteins as penicillin-binding proteins (PBPs), tartronate semialdehyde reductase, ethanolamine utilization protein, shikimate kinase I, allantoinase, predicted SAM-dependent methyltransferase, L-glutamine: D-fructose-6-phosphate aminotransferase (GFAT), phospho-glucosamine mutase, predicted N-acetylmannosamine kinase, and predicted N-acetylmannosamine-6-P epimerase. Up-regulation of PBPs, one of primary target sites of antibiotics, might be responsible for the multidrug resistance in E. coli with increasing amount of target sites. Up-regulation of GFAT enzyme may be related to the up-regulation of PBPs because GFAT produces N-acetylglucosamine, a precursor of peptidoglycans. One of GFAT inhibitors, azaserine, showed a potent inhibition on the growth of E. coli KD43162. In conclusion, up-regulation of PBPs and GFATs with the loss of 36 kDa OMP refers the multidrug resistance in E. coli KD 43162.

• Korean Journal of Veterinary Service
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• v.37 no.1
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• pp.19-27
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• 2014

This study was conducted to investigate the antimicrobial resistance, presence of ${\beta}$-lactamase genes and integrons in 83 ESBL-producing Escherichia coli isolated from Nakdong river and Geumho river in Daegu. Among the ${\beta}$-lactam antimicrobials, all isolates were resistant to ampicillin, cephalothin, cefamandole and cefotaxime, followed by piperacillin (98.8%), ampicillin/sulbactam (86.7%), aztreonam (60.2%) and cefepime (59.0%), whereas resistance to piperacillin/tazobacram, ticarcillin/clavulanic acid and cefoxitin was less than 30%. Many of the ESBL-producing Escherichia coli were also resistant to non-${\beta}$-lactams antimicrobials such as nalidixic acid (83.1%), sulfonamides (72.3%), ciprofloxacin (62.7%) and gentamicin (38.6%). All isolates showed resistance to seven or more antimicrobial agents. The most frequently detected gene was $bla_{TEM+CTX-M}$ (49.4%), followed by $bla_{CTX-M}$ (27.7%), $bla_{TEM}$ (6.0%) and $bla_{OXA}$ (1.2%). But $bla_{SHV}$ was not found. Class 1 integrons were found in 61.4% (51 isolates) of isolates, however, class 2 and 3 integrons were not detected. The results showed water from Nakdong river and Geumho river is contaminated with ESBL-producing E. coli isolates. These results suggest the need for further investigation of antibiotic resistant bacteria to prevent public health impacts in the water environment.

• Tuberculosis and Respiratory Diseases
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• v.76 no.2
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• pp.80-83
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• 2014

Patients with acquired immunodeficiency syndrome (AIDS) are at higher risks of bacterial pneumonia than the general population, and the pathogen is the most commonly involved Streptococcus pneumoniae. We hereby report a case of pneumococcal pneumonia associated with leptomeningitis, osteomyelitis and epidural abscess in a patient with AIDS. He is being successfully treated with ampicillin/sulbactam and clindamycin. And because the pneumococcal infection is usually associated with morbidity and mortality rates in the setting of AIDS, we should consider for pneumococcal vaccinations among the AIDS populations.

• Journal of Veterinary Clinics
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• v.34 no.1
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• pp.23-26
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• 2017

Otitis externa (OE) is an inflammatory disease of the externa auditory meatus that occurs commonly in dogs. Antimicrobial susceptibility tests should be performed in case of chronic OE for successful treatment. In this study, identification and antimicrobial susceptibility test of bacteria isolated from dogs with chronic OE was performed. From 60 dogs with chronic OE, 60 bacterial species were identified. The most frequently identified species were Staphylococcus spp. (51%), followed by Pseudomonas spp. (15%) and Enterococcus spp. (14%). A single bacterial infection and multiple bacterial infections were observed in 67.5% and 32.5%, respectively. Staphylococcus spp. was susceptible to imipenum. Pseudomonas spp. was found to be susceptible to amikacin, cefepime, imipenum and piperacillin-tazobactam. Enterococcus spp. was susceptible to ampicillin-sulbactam, imipenum and piperacillin-tazobactam. Imipenum was highly susceptible antibiotic against both Gram-positive and negative bacteria whereas aztreonam and vancomycin were highly resistant. These results could suggest the optimal choice of antimicrobial agents for canine OE treatment.

• Clinical and Experimental Pediatrics
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• v.48 no.7
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• pp.760-765
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• 2005

Purpose : We studied the changes in antibiotic sensitivity to the causative organisms of urinary tract infection(UTI), in order to provide useful information on the choice of adequate drugs in the treatment of UTI. Methods : We retrospectively analyzed the major causative organisms and their antibiotic sensitivities in 69 patients diagnosed with UTI in the Department of Pediatrics, Samsung Cheil Hospital from 2002 to 2003. Results : The frequency of UTI was the highest in infants younger than 1 year of age(88.4 percent). The male to female ratio was 3.05 : 1. Escherichia coli was the most frequent organism(78.3 percent), followed by Klebsiella(11.6 percent), Pseudomonas(2.9 percent), Proteus(2.9 percent), Enterobacter, Morganelle, and Enterococcus(1.4 percent) in descending order. Antibiotic sensitivity of gram negative organisms was above 90 percent against imipenem, amikacin, 80 percent against aztreonam, cefepime, ceftriaxone, 50-70 percent against gentamicin, trimethoprime-sulfamethoxazole (TMP/SMX), and 23 percent against ampicillin(23.4 percent). Conclusion : Antibiotict sensitivity of gram negative organisms was high to amikacin and third generation cephalosporins but low to ampicillin, gentamicin and TMP/SMX. The use of ampicillin or TMP/SMX, as the first choice of the empiric and prophylactic treatment for UTI, should be reconsidered and investigated further.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.285-295
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• 2014

This study was conducted to survey the epidemiological characteristics and the isolated strains for pathogenic E. coli which was the major causative organisms for food poisoning occurred at school food services in the Gyeonggi-do area during the past three years. We investigated 19 accidents of food-borne disease outbreaks by pathogenic E. coli at school food services from 2010 to 2012. Food-borne disease outbreaks by pathogenic E. coli were usually occurred at direct management type (18 accidents, 95%) and high schools. For the seasonal factors, 13 accidents (65%) were occurred in June to September, especially the end of August and September after the summer holidays. The first patients were occurred on Wednesday (7 accidents, 37%) and Thursday (7 accidents, 37%), and they were mainly reported on Thursday (7 accidents, 37%) and Friday (5 accidents, 26%). The exposure of risk was estimated in Monday (4 accidents, 21%), Tuesday (7 accidents, 37%) and Wednesday (4 accidents, 21%), and kimchi (5 accidents, 50%) was estimated as the food of the high risk responsible for the outbreaks. 98 isolates of pathogenic E. coli consisted of PEC (50%), ETEC (34%), EAEC (15%), and EHEC (1%). The antibiotic resistance of pathogenic E. coli showed in the descending order of ampicilline (40%), nalidixic acid (37%), trimethoprim/sulfamethoxazole (24%), and tetracycline (19%). The antibiotics of second and third generation cephalosporins, cabarpenem, aminoglycosides, and second generation quinolones had antimicrobial susceptibilities and cefalotin, ampicillin/sulbactam and chloramphenicol showed medium resistance at 29%, 25%, and 6% respectively, and 70% of isolates were resistant to more than one antibiotic. By the PFGE analysis, they were classified into nine major groups and 31 profiles with 57% pattern similarity. It was very difficult to find the correlation of antimicrobial susceptibilities and genotype in the small scale-food poisoning, but the similarity of antimicrobial resistance and PFGE patterns in the large scale-food poisoning enabled the outbreaks to estimate the same pathotype of E. coli derived from identical origins.

• Pediatric Infection and Vaccine
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• v.6 no.2
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• pp.194-202
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• 1999

Background : Group B ${\beta}$-hemolytic Streptococcus(GBS) has been the major pathogen of neonatal sepsis in western country. In contrast, GBS has played little role in neonatal sepsis in Korea. But recently, neonatal GBS infections are encountered more frequently. It is important to characterize the clinical and epidemiological features of GBS infection in Korean children. Methods: We reviewed retrospectively the medical records of twenty-seven infants and children with GBS infection experienced at the Seoul National University Children's Hospital during 14 year-period from June, 1985 to June, 1999. Fourteen strains isolated from blood and cerebrospinal fluid were serotyped. Minimum inhibitory concentrations of 10 strains were determined by agar dilution method for penicillin, ampicillin, ampicillin with sulbactam, cefarolin, cefuroxime, and cefuiaxone. Results: The numbers of cases with GBS infection increased in 1990s. Among twenty seven cases, twenty-five cases were under three months of age and both of two cases with underlying disease occurred at three years of age. All neonatal infections were late-onset type and meningitis predominated. Serotypes were III(6 strain), Ib(4), Ia(l) and V(2). All of the strain were susceptible to all of the antibiotics tested. Conclusion: GBS infections in infants were increasingly recognized. GBS should be considered as an etiological agent of neonatal sepsis or meningitis in Korea. Maternal screening and prophylactic antibiotic therapy may be considered.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.9-14
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• 2010

In this study, lactic acid bacteria with high angiotensin converting enzyme inhibitor activity were isolated from Korean fermented food, such as kimchi and salted seafood. The strain HLJ59, isolated from salted shrimp showed the highest angiotensin converting enzyme inhibitor activity in DeMan Rogosa Sharpe broth. Optimum growth temperature of Lactobacillus brevis HLJ59 was at $34^{\circ}C$. Acid treatment at pH 3.0 for 1.5 h decreased cell viability from $9.9{\times}10^8$ CFU/ml to $3.11{\times}10^4$ CFU/ml. The bile extract concentration of 0.3%, 0.5%, and 1.0% in MRS broth did not inhibit the growth of HLJ59. Isolated strain HLJ59 showed more sensibility to amikacin, gentamycin, neomycin, streptomycin, kanamycin, cefmetazole, cephalothin, ampicillin, ticarcillin, sulbactam+ampicillin, amoxicillin+clavulanic acid (AMC), tetracycline, and sulfamethoxazole+trime thoprim (SXT) as compare to other 7 different antibiotics. However, it showed more resistance to cefoxatin, ceftnaxone, penicillin, ciprofloxacin, nalidixic acid, lincomycin, and chloramphenicol.