• Pediatric Infection and Vaccine
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• v.4 no.1
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• pp.79-89
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• 1997

Purpose : Neonatal bacterial meningitis is the disease which clinical manifestations are nonspecific and several neurologic complications may occur. We studied neonatal bacterial meningitis, particularly in treatment and prognosis according to causative organisms -gram positive and gram negative bacteria- to assist in treatment of neonatal bacterial meningitis. Methods : We analysed twenty-four cases retrospectively who had been admitted in NICU or pediatric ward in Chung-ang Gil hospital from Jan. 1991 to Jun. 1996, and who had proven causative organisms in culture or latex agglutination[n test in CSF. Results : 1) The ratio of male to female was 2.4: 1. The mean birth weight and gestational age in cases with gram positive bacterial meningitis were $2.91{\pm}0.79kg$ and $38.4{\pm}2.74$ weeks and those in cases with yam negative bacterial meningitis were $3.30{\pm}0.90kg$ and $37.7{\pm}3.33$weeks respectively. There was no significant difference between the two groups. 2) The perinatal predisposing factors were pematurity, mecoinium staining amnionic fluid, matemal diabetes and pregnancy-induced hypertension, etc. The clinical manifestations Were fever, seizure, poor oral intake and fontanel bulging, etc. There were eleven cases with early onset bacterial meningitis(four cases by gram positive bacteria, seven cases by gram negative bacteria), and thirteen cases with late onset bacterial meningitis(seven cases by gram positive bacteria, six cases by gram negative bacteria). There was no significant difference between the two groups in terms of onset. 3) There were eleven cases with yam positive bacterial meningitis and they were coagulase-negative staphylococci(three cases), group B streptococci(three cases), Staphylococcus aureus(two cases), Streptococcus viridans(two cases), and enterococci(one case). And there were thirteen cases with gram negative bacterial menir gitis and they were Escherichia coli(seven cases), Klevsiella pneumoniae(three cases), Pseudomonas aeruginosa(one case), Acinetobactor(one case) and Enterobacter(one case). 4) The initial CSF WBC counts in cases with yam negative bacterial meningitis were significantly higher than those in cases with gram positive bacterial meningitis but the CSF protein and glucose levels were no significant difference in the two groups statistically. 5) The number of cases with abnormal findings in brain ultrasonography was seven in gram positive bacterial meningitis and ten in gram negative bacterial meningitis. 6) There were relatively high sensitivity to penicillin derivatives, the first generation cephalosporin and vancomycin in gram positive bacteria and to the third generation cephalosporin and amikacin in gram negative bacteria. 7) The mortality rate was 20.8%(5 cases were expired or discharged hopelessly). There was no significant difference between the two groups in prognosis. Conclusions : We recommend active treatment in noenatal bacterial meningitis to improve prognosis because the prognosis is poor.

• Pediatric Infection and Vaccine
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• v.19 no.3
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• pp.131-140
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• 2012

Purpose : This study was performed to identify the etiologic agents and antimicrobial susceptibility patterns of organisms responsible for bloodstream infections in pediatric cancer patients for guidance in empiric antimicrobial therapy. Methods : A 5-year retrospective study of pediatric hemato-oncologic patients with bacteremia in Seoul National University Children's Hospital, from 2006 to 2010 was conducted. Results : A total of 246 pathogens were isolated, of which 63.4% (n=156) were gram-negative, bacteria 34.6% (n=85) were gram-positive bacteria, and 2.0% (n=5) were fungi. The most common pathogens were Klebsiella spp. (n=61, 24.8%) followed by Escherichia coli (n=31, 12.6%), coagulase-negative staphylococci (n=23, 9.3%), and Staphylococcus aureus (n=22, 8.9 %). Resistance rates of gram-positive bacteria to penicillin, oxacillin, and vancomycin were 85.7%, 65.9%, and 9.5%, respectively. Resistance rates of gram-negative bacteria to cefotaxime, piperacillin/tazobactam, imipenem, gentamicin, and amikacin were 37.2%, 17.1%, 6.2%, 32.2%, and 13.7%, respectively. Overall fatality rate was 12.7%. Gram-negative bacteremia was more often associated with shock (48.4% vs. 11.9%, P<0.01) and had higher fatality rate than gram-positive bacteremia (12.1% vs. 3.0%, P=0.03). Neutropenic patients were more often associated with shock than non-neutropenic patients (39.6 % vs. 22.0%, P=0.04). Conclusion : This study revealed that gram-negative bacteria were still dominant organisms of bloodstream infections in children with hemato-oncologic diseases, and patients with gram-negative bacteremia showed fatal course more frequently than those with gram-positive bacteremia.

• Clinical and Experimental Pediatrics
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• v.45 no.6
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• pp.719-726
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• 2002

Purpose : Neonates in neonatal intensive care units(NICU) have a high risk of acquiring nosocomial infection because of their impaired host defence mechanism and invasive procedures. Nosocomial infection result in considerable morbidity and mortality among neonates. This study was carried out to survey both the epidemiology of nosocomial infection in our NICU and the annual trends of pathogens. Methods : We retrospectively reviewed culture proven nosocomial infection which occurred in our NICU from January 1995 to December 1999. The data included clinical characteristics, site of infection, pathogens, and mortality. Results : Nosocomial infection rates was 9.0 per 100 NICU admissions during the five-year period. Major sites of infection were bloodstream(32.3%), skin(18.4%), endotracheal tube(17.2%), and catheter(10.6%). The most common pathogen was S. aureus(29.9%). and the others were coagulase- negative staphylococci(CONS)(14.8%), Enterobacter(12.4%), and Candida(9.0%). During the five-year period, nosocomial infection rates increased from 9.5 to 11.6 per 100 admissions with the increase of CONS, Candida, Klebsiella, and Acinetobacter baumannii. The infection rate of S. aureus decreased. Multiple episodes of nosocomial infection occurred in 26.1% of all nosocomial infections. Overall bloodstream infection rates were 3.6 per 100 NICU admissions during five years. CONS(29.1%) and S. aureus(27.1%) were the two most common pathogens. Increasing rates of bloodstream infection by CONS, Candida, Klebsiella, and Acinetobacter baumannii were observed. Bloodstream infection related mortality was 11.9%. Conclusion : The predominant pathogens of nosocomial infection in NICU were S. aureus and CONS. Bloodstream infection, the most frequent nosocomial infection, should be a major focus of surveillance and prevention efforts in NICU.

• Tuberculosis and Respiratory Diseases
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• v.49 no.1
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• pp.72-81
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• 2000

Backgrounds : Authors evaluated the quantitative culture of bronchoalveolar lavage fluid(BALF) in patients who were being treated with antimicrobial agents and the characteristics of isolated microorganism. Method : A prospective study was done with 25 patients under mechanical ventilation and antimicrobial treatment in ICU and NCU of Yongdong Severance Hospital from Apr. to Sep. 1999. Patients were classified into two groups: control group (n=5) and patients with VAP (n=20). The threshold of quantitative culture of BAL fluid in the diagnosis of VAP was $10^4$ cfu/ml. Results : 1) In gram staining of BALF, one patient in the control group and four in the VAP group showed positive results. Quantitative culture of BALF showed no organisms in the patients in the control group and in 9 VAP patients. Therefore the overall sensitivity was 43.8%. 2) Frequency of isolated organisms cultured above diagnostic threshold was in the following order: E. cloaclae, S. aureus, K. pneumoniae, and A. baumani. S. aureus and Staphylococcus coagulase(-) were a11 resistant to oxacillin. Seven out of 10 isolated G (-) organisms were suspected to be organisms producing extended spectrum $\beta$-lactamase (ESBL). 3) The concurrence between gram staining of sputum aspiration and that of BALF was only in 1 case. And the concurrence of culture results was observed in 3 cases. Conclusion : The sensitivity of gram staining and quantitative culture of BALF from patients under antibiotic therapy and the concordance rate between conventional tracheal aspiration and BAL were low, facts which were important in interpretation the data. Since the frequency of drug resistance organisms was not different from that of foreign data, antibiotics must be prudently selected and used.

• Childhood Kidney Diseases
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• v.2 no.2
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• pp.95-103
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• 1998

Purpose : To find and solve the common problems of peritoneal dialysis(PD) by analysing the clinical data of pediatric PD performed in Korea. Methods : 264 cases of CAPD and acute PD had been performed from Nov.1987 to Oct. 1997 in 17 institutions of pediatric nephrology in Korea. Results : CAPD was performed in 114 cases. The mean age of the patients was $10.5{\pm}6.6$ years and male to female ratio was 1.4:1. The original renal diseases of ESRD were proven in 92 cases($80\%$). The common renal disease of ESRD were FSGS($17\%$), reflux nephropathy ($11\%$), chronic glomerulonephritis($9.6\%$). Mean duration of CAPD was $20{\pm}16.9$ months. Peritonitis was the most common complication and incidence was one episode/18.2 patient-months. Other complications were exit site infection in 10 cases, obstruction in 7 cases, leakage of dialysate in 6 cases. The most common etiologic organism of peritonitis was staphylococcus aureus and the next was staphylococcus coagulase(-). Acute PD was performed in 150 cases. Most common underlying causes were congenital heart disease, hemolytic uremic syndrome, sepsis and dehydration. The mean duration was $10.3{\pm}11.3$ days. The most common complication was peritonitis($20.6\%$). The most common etiologic organism was staphylococcus aureus and coagulase(-), acinetobactor and pseudomonas. Conclusion : Reflux nephropathy should be emphasized in early diagnosis and treatment to prevent ESRD. Incidence of congenital anomaly($7\%$) as a original disease of ESRD was relatively low in Korea. Growth status was not significantly improved after CAPD. In acute PD, the incidence of peritonitis was rapidly increased at 2weeks after beginning of dialysis.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.4
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• pp.407-412
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• 2017

The aim of this study was to shorten the time required for subculture and bacterial identification and obtain a simple and rapid identification method for new test methods for bloodstream infections. The following results were obtained using a mass spectrometer. In Vitek 2, 208 (81.8%) cases were well-identified and 45 isolates were not identified in blood cultures. Among 208 cases, 146 (57.5%) were Gram positive bacteria and 108 (42.5%) were Gram negative bacteria. In total, 233 were identified to the species level and 21 were identified to the genus level. The identification error was found to be Propionibacterium acnes as Clostridium bifermentans. The accuracy of Enterobacteriaceae, glucose non-fermentative bacilli (GNFB), and staphylococci were 81/83 (97.6%), 12/15 (80.0%), and 72/85 (84.7%), respectively. The concordance rate of Vitek 2 and Vitek MS by the direct method was 81.8% and 45 isolates were not identified. Most of the unidentified bacteria were Gram positive bacteria (N=37). The Gram positive bacteria were streptococci (14), coagulase-negative staphylococci (CNS) (11), enterococci (3), Staphylococcus aureus (2), Micrococcus spp. (2), Bacillus spp. (2) and Actinomyces odontolyticus, Finegoldia magna, and Peptostreptococcus spp. The results reporting time was reduced to 24~72 hours compared to the conventional method. The rate of identification of the aerobic and anaerobic cultures was similar, but the use of an anaerobic culture did not require a dissolution process, which could shorten the sample preparation time. These results suggest that the method of direct identification in blood cultures is very useful for the treatment of patients. In further studies, it might be necessary to further improve the method for identifying streptococci and CNS, which were lacking in accuracy in this study.

• Childhood Kidney Diseases
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• v.12 no.2
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• pp.213-220
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• 2008

Purpose : This study aims to verify the effectiveness of initial empirical antibiotic choice recommended by the International Society for Peritoneal Dialysis(ISPD) guide among Korean children. Methods : We have collected data on peritonitis from January 2001 to December 2007 in Samsung Medical Center. Results : Of the 42 patients, 48 episodes of peritonitis had occurred in 21 patients. The rate of peritonitis was one episode over 35.3 patient-months. Mean dialysis duration before peritonitis was 18.06$\pm$15.81 months. Gram-positive organisms accounted for 58.3% of all episodes. Of the gram-positive organisms, the most common pathogen was Staphylococcus aureus(29.2%), the next common pathogens were Coagulase negative staphylococcus(14.6%) and Streptococcus species(6.3%). 35.7% of gram-positive pathogens were resistant to 1st cephalosporin. However, in patients younger than 4 years old, 50% of gram-positive pathogens were resistant to 1st generation cephalosporin. 10 episodes of peritonitis were methicillin-resistant and were treated by vancomycin. Of the gram-negative organisms, E. coli was the most common (8.3%). 64.8% of all pathogens were sensitive to cephalothin or ceftazidime. Conclusion : The empirical therapy with 1st generation cephalosporin and ceftazidime can be also effective to peritoneal dialysis associated peritonitis in Korean children. However, in patients younger than 4 years old, glycopeptide should be considered as the first empirical therapy in Korean children.

• 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.

• Pediatric Infection and Vaccine
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• v.28 no.3
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• pp.133-143
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• 2021

Purpose: This study aimed to determine the incidence of central line-associated bloodstream infection (CLABSI) in the neonatal intensive care unit (NICU), evaluate the patients' clinical characteristics, and identify the etiologic agents for guidance in prevention and treatment. Methods: A retrospective chart review study of infants classified as having CLABSI was conducted at the NICU of Seoul National University Bundang Hospital from January 2016 to December 2020. Results: Of the 45 infants, 53 had CLABSIs within a follow-up period of 18,622 catheter days. The incidence of CLABSIs was 2.85 per 1,000 catheter days. The most common catheter type was a peripherally inserted central catheter (n=47, 81%). A total of 57 pathogens were isolated, of which 57.9% (n=33) were Gram-positive bacteria, 36.8% (n=21) were Gram-negative bacteria, and 5.3% (n=3) were Candida spp. The most common pathogens were Staphylococcus aureus (n=12, 21%) and coagulase-negative staphylococci (n=12, 21%), followed by Klebsiella aerogenes (n=8, 14%). The median duration of bacteremia was 2 days, and 19 episodes showed bacteremia for 3 days or more. The mortality rate of infants within 14 days of CLABSI was 13.3% (n=6). Conclusions: This study analyzed the incidence of CLABSI and the distribution of pathogens in the NICU. Continuous monitoring of CLABSI based on active surveillance serves as guidance for empiric antibiotic use and also serves as a tool to assess the necessity for implementation of prevention strategies and their impact.

• Pediatric Infection and Vaccine
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• v.9 no.2
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• pp.163-174
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• 2002

Background : To delineate the changes in the causative agents of neonatal sepsis and their antimicrobial susceptibilities in the neonatal intensive care unit and nursery of Hanyang University Hospital during the past 10 years. Methods : Hospital records of 15,144 patients hospitalized at the NICU and nursery of Hanyang University Hospital from 1989 to 1998 were reviewed and neonates diagnosed of neonatal sepsis were sorted and included in the study. The study period was divided into Period A(the first 5 years) and Period B(the second 5 years) to analyse causative agents and their antimicrobial susceptibilities. Results : Neonatal sepsis was diagnosed in 170 patients(1.1%{Period A 1.2%, Period B 1.0%}) among the total of 15,144 inpatients. Two hundred isolates(Period A 109 isolates, Period B 91 isolates) were identified in 186 blood cultures(Period A 99 cultures, Period B 87 cultures) from 170 patients(Period A 91 patients, Period B 79 patients). The average age at the onset of the disease, when the initial blood culture was drawn, was 12.3 days old(Period A 8.8 days, Period B 16.3 days), and the proportion of the early onset disease was 34.7% in Period A and 23.0% in Period B, indicating that neonatal sepsis developed earlier during Period A. Among the isolated organisms including Gram positive bacteria[132(66.0%)], Gram negative bacteria [60(30.0%)], and fungi[8(4.0%)], coagulase negative Staphylococcus(CNS) was the most common organism(69/34.5%), followed by Staphylococcus aureus(36/18.0%), Klebsiella pneumoniae(17/8.5%), Enterococcus(12/6.0%), Enterobacter cloacae(8/4.0%), Escherichia coli(6/3.0%), and Pseudomonas aeruginosae(5/2.5%). The isolated fungi were Candida parapsilosis, Candida albicans, and Trichosporon pullulans. CNS, S. aureus and Acinetobacter baumannii were isolated more frequently in Period A compared to Period B. Antimicrobial susceptibilities of CNS and S. aureus to methicillin and the first generation cephalo sporins were decreased in Period B compare to Period A, those to aminoglycosides were increased in Period B, and vancomycin resistant strains were not identified. K. pneumoniae, Enterococcus, E. coli, and P. aeruginosa were isolated less frequently in Period B, compared to Period A. For K. pneumoniae, antimicrobial susceptibilities to the first generation cephalosporins were low in both Periods A and B, those to tobramycin and gentamicin were increased in Period B, and those to amikacin, ceftriaxone, and trimethoprim-sulfamethoxazole were high in both Periods A and B. Antimicrobial susceptibilities of Enterococcous to ampicillin, penicillin, and the first generation cephalosporins were decreased in Period B, but vancomycin resistant strains were not identified. Conclusion : The occurrence rate of neonatal sepsis during the past 10 years in the NICU and nursery of the Hanyang University hospital was 1.1%, and the most common causitive agents were CNS and S. aureus, to which the antimicrobial susceptibilities to the first line drugs decreased in the later half of the study period with no vancomycin resistant isolates identified. Group B Streptococcus known to be the most common agent causing neonatal sepsis was not identified, and K. pneumoniae was isolated more commonly during the later half of the study period without decreased antimicrobial susceptibilities.