• Pediatric Infection and Vaccine
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• v.27 no.1
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• pp.35-44
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• 2020

Purpose: This study aimed to investigate the clinical features of recurrent urinary tract infection (UTI) in children with vesicoureteral reflux (VUR) and to compare the causative uropathogen and antibiotic susceptibility between the first and recurrent UTI episodes. Methods: We retrospectively reviewed the medical records of children with VUR who had recurrent UTI. Group 1 included patients in whom the same pathogen caused the first and recurrent UTI episodes. Group 2 included patients in whom different pathogens caused the first and recurrent UTI episodes. Results: During a 13-year study period (2005-2018), 77 children with VUR experienced at least one episode of UTI. Among these, 47 patients (61.0%) had recurrent UTI. Of the children with recurrent UTI, 19 (40.4%) were in group 1 and 28 (59.6%) were in group 2. Escherichia coli was the most commonly isolated uropathogen (n=37; 39.4%) in both episodes of recurrent UTIs, followed by Klebsiella pneumoniae (n=18; 19.1%), Enterococcus faecalis (n=14; 14.9%), and Enterobacter aerogenes (n=7; 7.4%). Although the difference was not significant, the rate of resistance to the antibiotics ceftazidime, piperacillin/tazobactam, and trimethoprim-sulfamethoxazole increased in patients with the second episode of E. coli recurrence in group 1, and that to cefotaxime, ceftazidime, piperacillin/tazobactam, and meropenem increased in children with the second episode of E. aerogenes recurrence in group 1. Conclusions: When selecting empirical antibiotics for recurrent UTI in children with VUR, it is important to consider that the pathogen and antimicrobial susceptibility of the previous UTI are not always the same in recurrent UTIs.

• Biomedical Science Letters
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• v.10 no.4
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• pp.501-506
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• 2004

Extended spectrum β-lactamase (ESBL) generated Enterobacteriaceae including Escherichia coli is responsible for resisting antibiotics, which is clinical problem. This study was performed to investigate the isolation rates of 111 strains having positive of VITEK ESBL test 111 ESBL-strains in each month and season and statistically to determine their patterns of antibiotic test. One hundred eleven ESBL-strains were collected among 1,688 strains of E. coli isolated from various clinical specimen of one general hospital in Busan during 2002 to 2003. Month rates of ESBL-strains were 0％ to 13.3％, while the seasonal rates were highest at autumns during two years. The resistance to ampicillin, cefazolin, azteronam, ceftriaxone, and cefepime were 100％ in 2002. In ampicillin and cefazolin the resistances were 100％ during the two years. There were significant differences of cefoxitin and piperacillin/tazobactam between the two years but not significant between specimens. Four groups were divided according to the pattern of resistance and then the highest group had 93∼100％ of the resistance to 8 drugs but not resistant to imipenem.

• Korean Journal of Clinical Laboratory Science
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• v.41 no.2
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• pp.47-51
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• 2009

A case of recurrent urinary tract infection by cysteine-requiring Escherichia coli in a 5-years-old child with congenital vesicoureteral reflux is described. This bacterium was not grown on MacConkey agar plate for overnight culture, and after 48hrs, tiny colonies were observed. These colonies were not identified by VITEK2 and Walkaway 96i without cysteine supplementation. The isolate was susceptible for cefotetan, ciprofloxacin and imipenem, and resistant for piperacillin/tazobactam, cephalothin, cefotaxime, ceftazidime, amikacin, gentamicin, and tobramycin.

• Tuberculosis and Respiratory Diseases
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• v.62 no.6
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• pp.506-515
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• 2007

Background: Nosocomial pneumonia in an intensive care unit (ICU) is associated with a high mortality rate. Diagnosing a respiratory tract infection in critically ill patients is still difficult but detailed information for the pathogens is needed to establish an adequate antimicrobial treatment. This study examined the causative organisms and their antimicrobial resistance using bronchoalveolar lavage (BAL) from patients suspected of having pneumonia in the ICU. Methods: From January 2004 to June 2006, ICU patients with diffuse lung infiltration were prospectively enrolled. The BAL was used to diagnose the respiratory infection, with 104 > or = organisms considered a positive result. The most common organisms and their antimicrobial resistances were analyzed from the quantitative BAL cultures in the burn ICU and non-burn ICU. Results: A total 72 patients were included, 35 (M 29, F 6) in the burn ICU and 37 (M 26, F 11) in the non-burn ICU. 27 patients (77.1%) in the burn ICU and 22 patients (59.5%) in the non-burn ICU met the criteria for a positive BAL culture. The major pathogens were Staphylococcus aureus, Acinetobacter species and Pseudomonas aeruginosa. All strains (100%) of Staphylococcus aureus isolated from BAL (9 cases) were methicillin-resistant (MRSA) in the burn ICU, but 5 strains (71.4%, 7 cases) were MRSA in the non-burn ICU. Regarding Pseudomonas aeruginosa, the rate of resistance to amikacin, ciprofloxacin, cefepime, imipenem, ceftazidime, piperacillin/tazobactam in the burn and non-burn ICU ranged from 45.5% to 90% and 25% to 50%, respectively. In addition, the rate of resistance of Acinetobacter species to the above drugs in the burn and non-burn ICU ranged from 81.8% to 100% and 62.5% to 100%, respectively. Conclusions: These results are expected to provide useful guidelines for choosing the effective empirical antimicrobial therapy in patients with lung infiltrations in the burn and non-burn ICU.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.2
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• pp.82-87
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• 2016

Enterotoxigenic Bacteroides fragilis (ETBF) produces enterotoxins known to be a virulence factor. Three isotypes of the B. fragilis toxin (BFT) gene have been identified: bft-1, bft-2, and bft-3. We investigated the presence of bft isotypes in clinical B. fragilis isolates and the antimicrobial resistance of BFT-negative and BFT-positive isolates. Overall, 537 B. fragilis isolates were collected from extraintestinal specimens over 8 years (2006~2013) from a university hospital in Korea. Samples were analyzed by multiplex PCR to identify the bft gene isotypes. Additionally, the antimicrobial susceptibility of 107 B. fragilis isolates (74 BFT-negative and 33 BFT-positive) was examined by the CLSI agar dilution method. PCR revealed a total bft gene detection rate of 30%, while 33% and 29% of blood and other extraintestinal isolates contained the gene, respectively. Among ETBF isolates, the most common isotype was bft-1 gene, followed by bft-2 and bft-3 (bft-1 77%, bft-2 14%, bft-3 9%). Resistance rates (%) for BFT-negative and positive isolates differed in response to various antimicrobial agents, with 3%, 5%, 1% and 38% of BFT-negative isolates and 3%, 6%, 3% an 42% of BFT-positive isolates being resistant to piperacillin-tazobactam, cefoxitin, imipenem, and clindamycin, respectively. Interestingly, neither BFT-negative nor positive isolates showed antimicrobial resistance to chloramphenicol and metronidazole. Overall, the proportion of ETBF from blood was similar to that of other extraintestinal sites and the bft-1 gene was the predominant isotype. Higher antimicrobial resistance rates were found in BFT-positive isolates than BFT-negative isolates, but these differences were not statistically significant.

• Pediatric Infection and Vaccine
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• v.24 no.2
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• pp.71-78
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• 2017

Purpose: The aim of this study was to identify the pathogens of blood stream infection (BSI) in children with hemato-oncologic disorders, to analyze susceptibility patterns of microorganisms to guide empirical antimicrobial therapy, and to compare temporal trends of the pathogen and antimicrobial susceptibility with those of previous studies. Methods: We retrospectively analyzed the medical records of children with hemato-oncologic disorders whose blood culture grew pathogens at the Seoul National University Children's Hospital between 2011 and 2015. Results: A total of 167 patients developed 221 episodes of bacteremia. Among 229 pathogens, gram-negative bacteria (GNB) accounted for 69.0% (64.0% in 2002 to 2005, 63.4% in 2006 to 2010); gram-positive bacteria (GPB) accounted for 28.8% (31.3% in 2002 to 2005, 34.6% in 2006 to 2010); and fungus accounted for 2.2%. Among GNB, Klebsiella species (53.2%, 84/158) and Escherichia coli (19.6%, 31/158) were common. Staphylococcus aureus (48.5%, 32/66) and viridans streptococci (21.2%, 14/66) were frequently isolated among GPB. The susceptibilities of oxacillin and vancomycin in GPB were 54.8% and 96.9% (51.5% and 95.5% in 2002 to 2005; 34.1% and 90.5% in 2006 to 2010), respectively, whereas in GNB, the susceptibilities of cefotaxime, piperacillin/tazobactam, and imipenem were 73.2%, 77.2%, and 92.6% (75.9%, 82.8%, and 93.4% in 2002 to 2005; 62.8%, 82.9%, 93.8% and in 2006 to 2010), respectively. There were no significant differences in the proportion of etiologic agents or the antimicrobial susceptibilities between the current study and that of the previous two studies from 2002 to 2010. Overall fatality rate was 13.1%. Conclusions: GNB predominated in BSI among children with hemato-oncologic disorders. The etiology of bacteremia and antimicrobial susceptibility were comparable to those of the previous studies. Thus, piperacillin/tazobactam can be used as the initial empirical antimicrobial agent in febrile neutropenia.

• Journal of Korean Society of Health-System Pharmacists
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• v.35 no.4
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• pp.391-399
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• 2018

Background : The Antimicrobial Stewardship Program promotes interdisciplinary interventions and targeted recommendations for the proper utilization of antibiotics. In particular, the aim of the program is to avoid indiscriminate use of broad-spectrum antibiotics based on the documented literature on the significant impact of unsystematic usage of antibiotics on the distribution of antibiotic-resistant microorganisms. To improve the care process for pneumonia treatment using antimicrobial agents, institution-level guidelines were established and disseminated at the Seoul National University Bundang Hospital in April 2016. In this study, we evaluated changes in the physicians'antibiotic prescribing patterns both before-and after-the implementation of the guidelines. Methods : The electronic medical records of inpatients who were prescribed with one or more antibiotics in May 2014 (Group A) and May 2016 (Group B) were reviewed. Data on demographic characteristics, clinical outcomes, and antibiotic prescriptions were collected and the prescription records were compared both before- and after- the implementation of the guidelines. Results : A total of 180 patients were included in the study: 77 patients in group A and 103 patients in group B. The baseline characteristics of the patients were not significantly different between the two groups. Community-acquired pneumonia was the most common diagnosis in both the groups and the difference was not significant (68.8% vs. 67.9%; p=0.67). The type of antibiotic prescriptions used for empirical treatment was not different between the two groups. The most commonly prescribed empirical antibiotics were cephalosporins, with no significant difference (p=0.31). One of the most inappropriately used antibiotics was piperacillin/tazobactam and the rate of prescription was similar in both the groups (p=0.68). The rates of appropriate empirical selection of antibiotics remained unaltered between the two groups (67.5% vs. 71.8%; p=0.53). Conclusions : Implementation of the guidelines only exhibited no significant effect on the antibiotic prescribing patterns of physicians for the treatment of pneumonia. To improve the adequate use of empiric antibiotics, more active interventions and closer monitoring of the feedbacks should be additionally considered and evaluated in future studies.

• 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 Clinical Laboratory Science
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• v.38 no.1
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• pp.22-25
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• 2006

Ochrobactrum anthropi, previously known as Achromobacter species biotypes 1 and 2 (CDC groups Vd-1, Vd-2), belong to the groups of non-Enterobacteriaceae- nonfermentative Gram negative bacilli. Achromobacter is not presently a recognized genus. Achromobacter xylosoxidans has been transferred to genus Alcaligenes as A. xylosoxidans subsp. xylosoxidans, and "Achromobacter" sp. group Vd has been named Ochrobactrum anthropi. O. anthropi was isolated from a blood culture. Organisms were identified as O. anthropi by use of the biochemical test and the VITEK 2(bioMerieux, USA). The Organism was susceptible only to colistin, imipenem, meropenem, and tetracycline, but were resistant to amikacin, aztreonam, cefepime, ceftazidime, cefpirome, ciprofloxacin, gentamicin, isepamcin, netilmicin, pefloxacin, piperacillin, piperacillin/tazobactam, ticarcillin, ticarcillin/clavulanic acid, tobramycin, and trimethoprim/sulfamethoxazole. We report the clinical and microbiologic characteristics of O. anthropi infection in the patient. This is the first case of O. anthropi infection after using a plant as medicine at Chosun University Hospital.

• Archives of Plastic Surgery
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• v.33 no.3
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• pp.330-334
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• 2006

Polymicrobial nature of diabetic foot infection has been well documented in the literature. Initial antibiotic therapy of diabetic foot infection is usually empiric until reliable culture data is shown. This study was carried out to determine the common bacteriological flora of diabetic foot infection and antimicrobial sensitivity pattern in order to enhance possible empiric treatment. The specimens were obtained from wounds of 207 cases of diabetic foot ulcer, and the bacteriological isolation, and antimicrobial susceptibility tests of the isolates were carried out by standard microbiological methods. Staphylococcus aureus was the most common isolate, with 46.2% of recover rate among total bacterial isolated cases. Among gram-negative organisms, Pseudomonas aeruginosa was most common. Gram-positive organisms showed significant susceptibility to clindamycin, trimethoprim/sulfamethoxazole, and levofloxacin, besides vancomycin. Cefoperazone, piperacillin/tazobactam, and amikacin in addition to imipenem were most effective agents compared to gram-negative organisms. Diabetic foot infection requires use of combined antimicrobial therapy for initial management. Our results indicate that the most effective antibiotic combination for diabetic foot infection of Korean patients is clindamycin plus cefoperazone.