• Journal of the Korean Society of Radiology
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• v.14 no.6
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• pp.833-839
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• 2020

Globally, infection prevention and social awareness have been greatly changed by the severe acute respiratory syndrome coronavirus, and as a result, the infection control guidelines and procedures for patients with high exposure to hospital-acquired infection are further strengthened and management and monitoring are more thorough. In order to prevent infection, sterilization should be carried out with the highest priority, and we will find a sterilization method that is low in cost, easy to install, and easy to operate, to present appropriate sterilization effects. In this study, the UV sterilizer was used to contaminate the caries bacteria with an output of 4 W and irradiation time of 60, 150, and 300 sec, and the laser was irradiated with outputs of 0.8 and 1.5 W at wavelengths of 266 and 355 nm, respectively. Ultraviolet sterilizer showed safety in infection prevention at over 150 sec, and laser showed safety in prevention at 1.5 W, 0.8 W, and 266 nm. As a result, the higher the output and the wavelength closer to 253.7 nm, the better the sterilization effect.

• Tuberculosis and Respiratory Diseases
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• v.52 no.3
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• pp.207-218
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• 2002

Background : Intensive care units (ICUs) are generally considered epicenters of antibiotic resistance and the principal sources of multi-resistant bacteria outbreaks. The antibiotic resistance in newly opened intensive care unit that has no microbial colonization on and around the devices was investigated. Materials and Methods : The authors analyzed the antibiotic resistance patterns for common hospital acquired-pneumonia pathogens in the ICUs(Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter spp.) at the newly opened ICU of Hanyang University Medical Center, Kuri Hospital during 6 years(1995-2000). Results : 1) Regarding Staphylococcus aureus, the resistance rate to methicillin was 15% at 1995, 21% at 1996, 20% at 1997, 23% at 1998, 22% at 1999, 55% at 2000. 2) Regarding Pseudomonas aeruginosa, the resistance rate to $3^{rd}$ cephalosporin was 50% at 1995, 50% at 1996, 78% at 1997, 40% at 1998, 77% at 1999, 39% at 2000. Imipenam was 0% at 1995, 27% at 1996, 65% at 1997, 12% at 1998, 16% at 1999, 12% at 2000. Ciprofloxacin was 0% at 1996, 56% at 1997, 36% at 1998, 57% at 1999, 58% at 2000. Tobramycin was 7% at 1995, 10% at 1996, 67% at 1997, 36% at 1998, 65% at 1999, 12% at 2000. Gentamycin was 14% at 1995, 36% at 1996, 67% at 1997, 36% at 1998, 65% at 1999, 12% at 2000. Amikacin was 14% at 1995, 30% at 1996, 61% at 1997, 16% at 1998, 39% at 1999, 18% at 2000. 3) Regarding Acinetobacter spp., the resistance rate to $3^{rd}$ cephalosporin was 92% at 1996, 89% at 1997, 88% at 1998,84% at 1999, 77% at 2000. Imipenem was 50% at 1996, 48% at 1997, 45% at 1998, 49% at 1999, 50% at 2000. Ciprofloxacin was 0% at 1996, 48% at 1997, 33% at 1998, 27% at 1999, 71% at 2000. Tobramycin was 67% at 1995, 100% at 1996, 89% at 1997, 95% at 1998, 87% at 1999, 77% at 2000. Gentamycin was 67% at 1995, 100% at 1996, 89% at 1997, 95% at 1998, 87% at 1999, 83% at 2000. Amikacin was 33% at 1995, 83% at 1996, 82% at 1997, 88% at 1998, 75% at 1999, 69% at 2000. Conclusion : The S.aureus resistance to methicillin, the Pseudomonas aeruginosa resistance to ciprofloxacin, and the Acinetobacter spp. resistance to ciprofloxacin have rapidly increased during 6 years. There is a need to pay speicial attention when using the the antibiotics for the above pathogens. This data may be useful in antibiotic therapy in newly opened intensive care units.

• Clinical and Experimental Pediatrics
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• v.46 no.3
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• pp.265-270
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• 2003

Purpose : To characterize the infants under 3 months of age with urinary tract infections(UTIs), and especially patients with bacteremia or meningitis Methods : Hospital records of all the infants under 3 months of age discharged from our hospital for 69 consecutive months with the diagnosis of initial episode of UTI were reviewed. UTI was defined when patients had fever with pyuria, and had urine culture results of ${\geq}10^5$ colony forming units/mL from a bag specimen. Patients with previously known urologic abnormality or immunodeficiency were excluded. Nosocomial infections were also excluded from the study. Results : The male:female ratio was 35 : 6. Of the urine cultures, 40(97.6%) yielded single pathogen, one yielded two pathogens. Escherichia coli was the predominant isolate from the urine. Five patients(12%) also had bacteremia. Pathogens isolated from the blood cultures were E. coli(4) and Enterococcus faecalis(1). No patient had culture-positive meningitis or cerebrospinal fluid pleocytosis. Clinical or laboratory findings between patients with and without bacteremia were not different significantly. The rate of vesicoureteral reflux(VUR) was 44%. The sensitivity of ultrasound for detection of VUR was 38%; specificity was 50%. Conclusion : Clinical and laboratory data were not helpful for identifying patients with bacteremia at the time of presentation. Consequently, blood cultures need to be obtained from all febrile infants under 3 months of age with UTIs. A large-scale study including the indication of lumbar puncture for infants with a febrile UTI and study of evaluation and treatment of infants under 3 months of age with UTIs are required.

• Neonatal Medicine
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• v.15 no.1
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• pp.61-66
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• 2008

Purpose : The purpose of this study was to describe the epidemiologic features of febrile illnesses in newborns and to predict the risk of serious infections in this population. Methods : A retrospective study was conducted on 123 full-term infants <30 days of age with an axillary temperature >38$^{\circ}C$ who were hospitalized between 2000 and 2006. Neonates with prenatal risk factors, congenital anomalies, antibiotic administration prior to admission to the hospital, or suspected hospital-acquired infections were excluded. We evaluated the symptoms, physical examination findings, laboratory data, and clinical course between the high- and low-risk groups for serious infections. Results : The high-risk group included 30 infants with the following diagnoses in order of frequency: aseptic meningitis, urinary tract infection, bacterial meningitis, infectious enteritis, sepsis concomitant with disseminated intravascular coagulopathy, bacteremia, pneumonia, cellulitis, and omphalitis. Leukocytosis and thrombocytopenia were statistically different between the two groups. Factors, such as moaning signs, seizures, body temperature, and pulse rate were statistically significant. Conclusion : Unlike previous studies, we included newborns with clinical bacterial infections and aseptic meningitis as the high-risk group. Leukocytosis, thrombocytopenia, moaning signs, seizures, and changes in vital signs were considered useful predictors for identifying febrile neonates at high-risk for serious infections in spite of a difference in the definition of serious infection.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.194-198
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• 2015

Enterococcus faecalis is a Gram-positive and facultative anaerobic bacterium that causes many hospital-acquired infections. Novel E. faecalis specific bacteriophage (phage) ECP3 that had been isolated from thirty-four environmental samples and characterized phenotypically and genotypically. ECP3 phage belongs to the family Myoviridae with contractile tail and lysed E. faecalis specifically but other bacteria including Enterococcus faecium. The genome was double-stranded linear DNA and its size was 145,518 bp comprising of 220 open reading frames. The GC content was 35.9%. The genome sequence showed 97% identity in 90% coverage region with Myoviridae phage PhiEF24C. ECP3 is the first E. faecalis-specific Myoviridae phage isolated in Korea which can be a promising antimicrobial agent against E. faecalis infections.

• Journal of Life Science
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• v.25 no.1
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• pp.29-36
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• 2015

Prodigiosin, a member of natural red pigment family, is produced by Serratia marcescens, and characterized by a common pyrrolylpyrromethane skeleton. This pigment has been reported with the effects of anticancer, immunosuppressant, antifungal, and algicidal activities. Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital infections. In this study, anti-MRSA properties of prodigiosin isolated from Serratia sp. PDGS 120915 were investigated. We identified and purified prodigiosin using high performance liquid chromatography (HPLC) and evaluated anti-MRSA activity. Purified prodigiosin inhibited the growth of MRSA. The minimum inhibitory concentrations (MICs) of prodigiosin were determined to $32{\mu}g/ml$ against the MRSA strains. Fractional inhibitory concentration (FIC) indices of ampicillin and penicillin were indicated synergistic effects of prodigiosin on MRSA.

• Korean Journal of Microbiology
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• v.49 no.3
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• pp.245-252
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• 2013

Pseudomonas aeruginosa and Acinetobacter baumannii are significant opportunistic pathogens in hospitals and are resistant to most antibiotics. Multidrug-resistant P. aeruginosa (MDRPA) and A. baumannii (MDRAB) cause severe human nosocomial infections and are more difficult to treat than methicillin-resistant Staphylococcus aureus (MRSA). Bifidobacteria are among of the most beneficial probiotics and have been widely studied for their antimicrobial activities. The present study explored the antimicrobial activity of Bifidobacterium sp. isolated from healthy Koreans against MDRPA and MDRAB. The antimicrobial activity of the isolates against MDRPA and MDRAB, which are resistant to ciprofloxacin, tobramycin, gentamicin, meropenem, and ceftazidime, was determined by modified broth microdilution methods using absorbance. Among all tested bifidobacteria isolates (nine B. adolescentis, three B. longum, and two B. pseudocatenulatum), the culture supernatant of B. pseudocatenulatum SPM1309 showed a strong growth inhibitory effect against MDRPA and MDRAB. No change in the turbidity of the mixture was observed during incubation, and its inhibitory effect occurred through bacteriostastic action. Moreover, the antibacterial activity was observed in the fraction with molecular weights <10 kDa of bifidobacteria culture supernatant, and the active fraction was heat-stable because it maintained its activity when heated at $70^{\circ}C$ for 10 min. The results suggest that this Bifidobacterium strain could have potential applications for alternative therapy in MDRPA and MDRAB infections.

• Pediatric Infection and Vaccine
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• v.16 no.2
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• pp.150-161
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• 2009

Purpose : Staphylococcus aureus causes a variety of infections, ranging from benign skin infections to fatal invasive infections. Recently, methicillin-resistant S. aureus (MRSA) infections have emerged in patients who do not have established risk factors. This study was conducted to characterize S. aureus infections in children with an emphasis on communityassociated MRSA infections at a tertiary care pediatric facility during a 3-year period. Methods : Four hundred twenty-nine cases of S. aureus infections diagnosed at the Seoul National University Children's Hospital between January 2004 and December 2006 were retrospectively reviewed. The cases were classified as hospitalonset (HO) or community-onset (CO), healthcare-associated (HA), or community-associated (CA) infections. Results : Among the 206 cases <1 year of age, 72%, 7%, and 21% were HO-HA, CO-HA, and CA infections, respectively, as compared to 48%, 28%, and 24% among the 223 cases >1 year of age. The proportion of CO-HA infections among HA infections (8.6% vs. 37.1%, P<0.001) and the proportion of HA infections among the CO infections (24.5% vs. 54.3%, P <0.001) were greater in older children than in infants. Overall, 57% of the isolates were methicillin-resistant. Twenty-nine (30%) of 96 CA strains were MRSA, and the most common site of CA-MRSA infection was the skin and soft tissues (26 cases). Conclusion : The methicillin resistance rate of S. aureus from CA infections was high and CA-MRSA was most often associated with skin and soft tissue infections.

• Pediatric Infection and Vaccine
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• v.17 no.2
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• pp.83-90
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• 2010

Purpose : Although the incidence of polymicrobial bloodstream infection (PBSI) has increased, only a few studies have so far focused on children. Therefore, in an effort to prevent more serious situations in pediatric patients, we analyzed the clinical features, organisms, and laboratory results of PBSI. Methods : We performed a retrospective review of the case records of 97 patients with polymicrobial bloodstream infection in the Severance hospital, from 2001 to 2008. Using t-test and chi-square test, we analyzed the underlying medical conditions, clinical characteristics, organisms, and laboratory results of those patients. Results : Annual incidence of polymicrobial bloodstream infection increased from 1.4 % in 2001 to 10.9% in 2008 in pediatric patients. Immunocompromised hemato-oncological malignancy was found in 31 (31.9%) patients, and was the most common underlying medical condition; cardiovascular disease was found in 15 patients (15.4%), neurologic disease in 10 patients (10.3%), and so on. Gram positive organisms were recovered in 143 cases and gram negative organisms were recovered in 101 cases of PBSI. Staphylococcus epidermidis was the most common organism. Factors affecting mortality included underlying medical disease, immune status, nosocomial infection, and central catheter-related infection, for which the rate of mortality showed a greater increase (P<0.05). Conclusion : Due to the close connection between PBSI and fatal conditions or high mortality, it requires more aggressive management. Compared with previous studies, we discovered that immunocompromised hemato-oncological malignancy was the most common underlying medical condition and that frequency of gram-positive bacteria and fungus isolated has increased.

• Tuberculosis and Respiratory Diseases
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• v.60 no.2
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• pp.228-234
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• 2006

Background : Acinetobacter baumannii is an important pathogen associated with nosocomial infections in intensive care units, and is responsible for nosocomial pneumonia, UTI, bacteremia, etc. The main concern is that this pathogen is often resistant to many antimicrobial agents, particularly to carbapenem. This study compared the clinical those of ICU admitted patients with the carbapenem resistant A. baumannii isolated from the sputum with characteristics of patients with carbapenem sensitive A. baumannii. Methods : A total of 49 patients with A. baumannii from a sputum culture who were admitted to the ICU from January to December 2003 were enrolled in this study. This study evaluated the demographic variables, mortality, APACHE II score, comorbidity, antibiotics used, hospital and ICU stay, Clinical Pulmonary Infection Score, and mechanical ventilation. A retrospective analysis was made by a review of the patients' medical records. Results : Carbapenem sensitive and resistant A. baumannii was isolated from 23 patients and 26 patients respectively. Univariate analysis revealed renal disease, the use of carbapenem and aminoglycoside to be statistically significant factors for carbapenem resistance. Multivariate analysis revealed carbapenem use(p=0.024; OR, 8.17; CI 1.32 to 50.68) to be positively associated with carbapenem resistance, and aminoglycoside use(p=0.026; OR, 0.18; CI, 0.04 to 0.82) to be negatively associated with carbapenem resistance. There was no significant difference in mortality between the carbapenem sensitive and resistant group(30 vs 42%. P=0.39). Conclusion : The occurrence of carbapenem resistant A. baumannii is positively associated with carbapenem use and negatively associated with aminoglycoside use. Carbapenem resistance in the sputum culture did not affect the mortality rate.