• Journal of Veterinary Science
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• v.21 no.4
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• pp.54.1-54.11
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• 2020

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of severe infections in humans and animals worldwide. Studies elucidating the population structure, staphylococcal cassette chromosome mec types, resistance phenotypes, and virulence gene profiles of animal-associated MRSA are needed to understand spread and transmission. Objectives: The objective of this study was to determine 1) clonal complexes and spa types, 2) resistance phenotypes, and 3) virulence/resistance gene profiles of MRSA isolated from animals in Switzerland. Methods: We analyzed 31 presumptive MRSA isolates collected from clinical infections in horses, dogs, cattle, sheep, and pigs, which had tested positive in the Staphaurex Latex Agglutination Test. The isolates were characterized by spa typing and DNA microarray profiling. In addition, we performed antimicrobial susceptibility testing using the VITEK 2 Compact system. Results: Characterization of the 31 presumptive MRSA isolates revealed 3 methicillinresistant Staphylococcus pseudintermedius isolates, which were able to grow on MRSA2 Brilliance agar. Of the 28 MRSA isolates, the majority was assigned to CC398 (86%), but CC8 (11%) and CC1 (4%) were also detected. The predominant spa type was t011 (n = 23), followed by t009 (n = 2), t034 (n = 1), t008 (n = 1), and t127 (n = 1). Conclusions: The results of this study extend the current body of knowledge on the population structure, resistance phenotypes, and virulence and resistance gene profiles of MRSA from livestock and companion animals.

• Pediatric Infection and Vaccine
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• v.18 no.1
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• pp.31-39
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• 2011

Purpose : This study was performed for the purpose of finding causative organisms and clinical features of septic arthritis or acute osteomyelitis in children. Methods : The study involved a retrospective review of the medical records of 63 microbiologically confirmed cases of acute pyogenic arthritis and osteomyelitis. All of the cases were brought about by community-associated infections and managed at the Seoul National University Children's Hospital or Seoul National University Bundang Hospital from June 2003 to July 2009. Results : The median age of all cases was 60 months and there were 35 males and 28 females. Major involved joints included the hip joint (15 cases), knee joint (7 cases), shoulder joint (4 cases), and elbow joint (4 cases). Also, major involved bones included the femur (20 cases), tibia (13 cases), humerus (7 cases), and radius (7 cases). Staphylococcus aureus was the most commonly identified causative organism, accounting for 49 cases (77.8%). Of the 49 isolates of S. aureus, methicillin-resistant S. aureus (MRSA) accounted for 8 cases (16.3%). Group B streptococcus spp. (GBS) and Salmonella spp. accounted for 3 cases, respectively. Nafcillin or cefazolin was often prescribed as an initial empirical antibiotic. There were 9 cases that were managed by a regimen that included vancomycin as the first choice. Fifty four cases (85.7%) recovered without any complications. Methicillin-sensitive S. aureus (MSSA), responsible for 41 cases, caused chronic complications in 3 cases. Of 8 cases caused by MRSA, 1 case showed chronic complication. There were no fatal cases. Conclusion : S. aureus remains the most common organism causing acute pyogenic arthritis and osteomyelitis of childhood acquired in the community. The high prevalence of methicillin resistance among S. aureus should be considered carefully in the selection of initial empirical antibiotics.

• Pediatric Infection and Vaccine
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• v.26 no.1
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• pp.11-21
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• 2019

Purpose: We aimed to investigate the epidemiological characteristics of Staphylococcus aureus bacteremia in Korean children. Methods: We retrospectively collected and analyzed data from the medical records of the patients with S. aureus bacteremia ${\leq}18years$ of age in Gil Medical Center from 2002 to 2016. Results: A total of 212 SAB cases were detected. The annual incidence of SAB from 2002 to 2016 ranged from 0.77 to 1.95 per 1,000 patients hospitalized. The neonate group (<28 days of age) and the pediatric group (28-18 years of age) were 51.4% (n=109) and 48.6% (n=103), respectively. According to the origin of infection, there were 93 cases (43.9%) of community-associated (CA)-SAB and 119 cases (56.1%) of healthcare-associated (HA)-SAB. The rates of HA-SAB among the neonate group and among the pediatric group were 64.2% and 47.6%, respectively (P=0.015). There was no difference in complications between CA-SAB and HA-SAB, but mortality was higher in HA-SAB. The proportion of methicillin-resistance S. aureus (MRSA) was the highest in neonates (88.1%), decreased with age, and was 36.4%-37.5% among children aged ${\geq}5years$. The MRSA proportion was 72.2%, showing no consistent trend over the period. Conclusions: The annual incidence of SAB and the proportion of MRSA in SAB remained constant in the recent 15 years in children. Judicious decision of antimicrobial agents for treatment considering the patient's age and the origin of infection is necessary.

• Journal of Chest Surgery
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• v.31 no.11
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• pp.1063-1069
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• 1998

Background: Multi-loculated empyema makes treatment difficult, and more so when thoracentesis or chest tube drainage fails. Materials and methods: From December 1991 to December 1997, we performed closed rib resectional drainage for 18 cases of loculated empyema on the fibrinopurulent or early chronic phase. Results: Surgery was performed on patients with loculated empyema complaining of persistent symptoms due to failure of treatment by thoracentesis(8 cases) or chest tube drainage(10 cases). Predisposing factors of empyema were pneumonia in 13 cases, clotted hemothorax in 3 cases, cholecystectomy, and tuberculous pleurisy in 1 case. Causal organisms were cultured in 8 cases(42.1%), and methicillin-resistant staphylococcus aureus was found in 3 cases, pseudomonas aeruginosa in 2 cases, and enterococcus aerogens, α-hemolytic streptococcus, and acinetobacter baumannii were found in 1 case. Size of loculations was various, and computed chest tomogram showed multiple loculations of empyema numbering 1∼4(mean 1.78±1.00). Operating time was relatively short, about 55∼140 mins(mean 102.8±30.8). All toxic symptoms including fever disappeared postopratively and general conditions improved very quickly in all patients. Length of chest tube indwelling time and hospital stay after surgery were 3∼42 days(mean 11.4±11.5) and 6∼36 days(mean 12.9±8.1), respectively. Complications of prolonged drainage occurred in 2 cases and no death occurred. There were no recurrences and chest x-rays taken 3∼6 months after surgery showed normal findings in 14 cases and slight pleural thickening in 4 cases. Conclusions: Closed rib resectional drainage requires very simple techniques and has excellent outcomes and little complications, therefore, we think that it is the choice of operation for patients with loculated empyema on the fibrinopurulent or early chronic phase.

• Clinical and Experimental Pediatrics
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• v.49 no.12
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• pp.1287-1295
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• 2006

Purpose : The importance of staphylococcal infections in NICU has been emphasized in terms of increased resistant strains and increased incidence of morbidity and mortality. In this study, we inrestignted the clinical characteristics and risk factors for staphylococcal infections, and looked into sensitivity trends of antibiotics in the era of a high rate of methicillin-resistant staphylococcus aureus (MRSA) in our society. Methods : This study included 240 neonates with positive blood, urine and other sites cultures for staphylococci who were admitted to NICU of Hanil General Hospital and Kyunghee University Hospital from January 2000 to December 2004. The analyses included clinical characteristics of staphylococcal infections and the relationship of incidence rate among various factors, including invasive procedures. Results : For 5 years, 3,593 patients were hospitalized in the NICU and 7,481 specimens were cultured from blood, urine, and other sites. During the study period, staphylococci were isolated from 240 patients, of whom 88 patients had MRSA, 41 patients methcillin sensitive staphylococcus aureus (MSSA), 63 patients S. epidermidis, 48 patients coagulase-negative staphylococcus (CNS) except S. epidermidis infections. The risk factors associated with staphylococcal infections were less than 37 weeks of gestational age, less than 7 on a 5 minutes Apgar score, receiving TPN, applied mechanical ventilation, use of central venous catheters and other tubes. The sensitivity to vancomycin was 100 percent. A relatively high sensitivity against teicoplanin, trimethoprim-sulfamethoxazole, chloramphenicol, clindamycin and low sensitivity against gentamicin and erythromycin were shown. Conclusion : To reduce staphylococcal infections in NICU, we need to monitor and manage premature neonates from the beginning of the birth process and to avoid as many invasive procedures as possible in NICU. Considering MRSA, control of preceding factors and early use of appropriate antibiotics is expected to reduce the morbidity and mortality caused by MRSA infections.

• Tuberculosis and Respiratory Diseases
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• v.42 no.1
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• pp.67-75
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• 1995

Background: Although we gain new knowledge, the problem of pneumonia will not be eliminated. We should understand who is at risk, why these people develop this problem, what causes the pneumonia, and how to manage and prevent respiratory infection. To clarify the alterations of the etiologies of bacterial pneumonia we analysed the recent causative organisms and evaluated the therapeutic implications. Methods: A retrospective four-year study of bacterial pneumonia was conducted in Soon Chun Hyang University Hospital. 190 episodes of bacterial pneumonia was investigated. Results: 1) The causative organisms were isolated in 173 cases on the sputum culture: 154 cases (89%) were gram negative bacilli and 19 cases(11%) were gram positive cocci. The major organisms were Pseudomonas species 49 cases(28%), Klebsiella pneumoniae 29 cases(17%), Enterobacter species 25 cases(14%), and Acinetobacter species 20 cases(12%) in decreasing order. Pseudomonas species(13 cases, 34%) were frequently found in nosocomial pneumonia. 2) The causative organisms were isolated in 16 cases on the blood culture: 7 cases(43%) were gram negative bacilli and 9 cases(57%) were gram positive cocci. The major organisms were Staphylococcus aureus(6 cases, 38%), Pseudomonas species(3 cases, 19%) in decreasing order. 3) In the susceptibility test of causative organisms to antimicrobial drugs, Pseudomonas was susceptible to amikacin, ciprofloxacin, aztreonam, ceftazidime(more than 50%) and resistant to piperacillin, gentamicin, carbenicillin(more than 60%). Klebsiella was susceptible to chloramphenicol, gentamicin, cefotetan(more than 70%) and resistant to carbenicillin, ampicillin(more than 70%). Staphylococcus was susceptible to methicillin(64%), and Streptococcus pneumoniae was susceptible to oxacillin(94%). 4) The response rate after antibiotics therapy was 81% and the mortality rate was 19%. Conclusion: As considering the changes of causative organisms and antibiotic resistance, it behooves us to exercise caution in dispending antibiotics in order to maximize their continued efficacy and to do appropiate antibiotics therapy based on cultures and susceptibility test.

• Journal of Yeungnam Medical Science
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• v.16 no.2
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• pp.347-356
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• 1999

Background: Exit site/tunnel infection causes considerable morbidity and technique failure in CAPD patients. We presently use a unique revision method for the treatment of refractory ESI/TI in CAPD patients and mupirocin prophylaxis for high risk patients. Materials and Methods: We reviewed 139 CAPD patients about the ESI/TI from October 1993 to February 1999 at Yeungnam University Hospital. At the beginning of the ESI. we usually started medications with rifampicin and ciprofloxacin and then changed the antibiotics according to the sensitivity test. If the ESI had persisted and there were TI symptoms (purulent discharge, abscess lesion around exit site). we performed catheter revision(external cuff shaving, disinfection around tunnel and new exit site on opposit direction) with a combination of proper antibiotics. We applied local mupirocin ointment at the exit site three times per week to the 34 patients who had the risk of ESI starting from October 1998. Results: The total follow-up was 2401 patient months(pt. mon). ESI occurred on 105 occasions in 36 out of 139 patients, and peritonitis occurred on 112 occasions in 67 out of 139 patients. The total number of incidences of ESI and peritonitis was 1 per 23.0 pt. mon and 1 per 2l.6 pt.mon. The most common organism responsible for ESI was Staphylococcus aureus (26 of 54 isolated cases, 48%), followed by the Methicillin resistant S. aureus(MRSA) (13 cases, 24%). Seven patients(5: MRSA. 2: Pseudomonas) had to be treated with a revision to control infection. Three patients experienced ESI relapse after revision. One of them improved with antibiotics, while another needed a second revision and the remaining required catheter removal due to persistent MRSA infection with re-insertion at the same time. But, there was no more ESI in these 3 patients who were received management to relapse (The mean duration: 14.0 months). The rates of ESI were significantly reduced after using mupirocin than before(1 per 12.7 vs 34.0 pt.mon, P<0.01). Conclusions: In summary, revision technique can be regarded as an effective method for refractory ESI/TI before catheter removal. Also local mupirocin ointment can play a significant role in the prevention of ESI.

• Clinical and Experimental Pediatrics
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• v.53 no.2
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• pp.173-177
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• 2010

Purpose : Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen that causes nosocomial infection in NICU. It contributes to neonatal morbidity and mortality with variable complications. This study was conducted to identify the risk factors associated with complicated MRSA bacteremia in neonates. Methods : We reviewed the medical records of 44 neonates with positive blood culture for MRSA who were admitted to the NICU of Pusan National University Hospital from January 2002 to December 2007. We compared various factors of the complicated and uncomplicated MRSA bacteremia cases. Results : Of the 44 neonates, 31 were male and 13, female. The mean gestational age and birth weight were $33.2{\pm}4.9$ weeks and $1,859.9{\pm}962.2g$, respectively. Twenty-one of infants were treated with a mechanical ventilator during a mean of $8.8{\pm}13.8$ days. There were 13 cases of complicated and 31 cases of uncomplicated MRSA bacteremia. Between the 2 groups, we compared the following variables: gestational age, birth weight, ventilator use, umbilical catheter use and central catheter insertion, $O_2$ inhalation, first oral feeding day after birth, underlying disease, transfusion, and initial vancomycin use. The underlying disease and transfusion were the risk factors related to complicated MRSA bacteremia. Conclusion : Complicated MRSA bacteremia is related to underlying disease and transfusion. Since this was a retrospective study with a small sample size, it offered limited capacity to compare complicated and uncomplicated MRSA bacteremia. A prospective study with a larger population is needed to determine the exact characteristics of MRSA bacteremia in NICU.

• Pediatric Infection and Vaccine
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• v.12 no.1
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• pp.67-74
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• 2005

Purpose : The incidence of mortality associated with respiratory difficulties is decreasing nowadays contributed to the development of neonatology. However, complications associated with mechanical ventilator are increasing. This study is to determine clinical manifestations, diagnositc availability of the endotracheal tip culture in patients with Ventilator-Associated Pneumonia(VAP) in neonatal intensive care unit(NICU). Methods : A retrospective analysis of 50 neonates who were admitted to the NICU of Kangnam Sacred Heart Hospital and had given mechanical ventilator from 1 January 2000 to 30 June 2003. VAP group defined as neonates who had pneumonia with mechanical ventilation longer than 48 hours. They were classified into VAP group(n=13) and control group (n=37) and the prevalence, microorganisms cultured from the endotracheal tube tip and risk factors were investigated. Results : The prevalence of VAP was 26.0%(n=13) and the most dominant microorganism cultured in our NICU was methicillin-resistant coagulase negative staphylococcus(MR-CNS) in 4 cases. Other microorganisms were Pseudomonas, Enterobacter, methicillin-resistant Staphylococcus aureus(MRSA) and Klebsiella. Gestational age, birth weight, Apgar score, respiratory distress syndrome, retinopathy of prematurity, bronchopulmonary dysplasia, sepsis, renal failure, pulmonary hemorrhage, pneumothorax were not different significantly between two groups except intraventricular hemorrhage(P<0.001) and patent ductus arteriosus(P<0.05). Duration of hospital stay and mortality rate were also not different significantly. Conclusion : VAP occurred at a significant rate among mechanically ventilated NICU patients. Despite of limitation of encotracheal tip culture, the most common microorganism was MR-CNS. We should be aware of occurrence of VAP in NICU neonate who were with mechanical ventilator and should treat with great care.

• Journal of Chest Surgery
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• v.39 no.2 s.259
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• pp.134-139
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• 2006

Background: Complications after surgery for esophageal cancer are various and not rare. Among them, pulmonary complication is well known as one of the most important insults which has negative influence on the postoperative course and results in mortality. So we attempted to analyze the factors which may have relation to postoperative pulmonary complication. Material and Method: The retrospective study was undertaken in 87 patients who underwent curative surgery for esophageal cancer from Jan. 1996 to Aug. 2005. We divided them into two groups, patients with pulmonary complication (group A, n=28), without pulmonary complication (group B, n=59). Statistical analysis was performed with Fisher's exact test. Result: The postoperative pulmonary complication developed in 28 patients ($32\%$). There was no difference between two groups in past medical history, preoperative pulmonary function, surgery time, anastomosis method, pathologic stage, and trial of neoadjuvant therapy. Age and incidence of cervical anastomosis were significantly higher in group A (p=0.001, p=0.023). The rate of routine postoperative ventilator care was significantly higher in group S (p=0.007). Chest tube indwelling time and hospital stay were significantly longer in group A (p=0.011, p=0.001). There were 6 postoperative deaths ($6.8\%$) and 5 deaths were related to pulmonary complication. Pneumonia was the most common cause of death and MRSA (methicillin resistant staphylococcus aureus) was the most common organism in sputum culture. Conclusion: Pulmonary complication after esophageal cancer surgery was the most important cause of death. Pulmonary complication was closely related to patient's age and cervical anastomosis. We think postoperative routine ventilator care is helpful for prevention of pulmonary complications, especially MRSA pneumonia, and reducing mortality.