• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.131-137
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• 2021

This study aimed at isolating lactic acid bacteria with anti-MRSA (methicillin-resistant Staphylococcus aureus) bacteriocin activity from fermented shrimp. We selected three strains, named Weissella sp. S1, S2, and S3, using analysis based on 16S rRNA gene sequences. All strains showed appropriate growth in an MRS medium containing 5% (w/v) NaCl and showed antibacterial activities against Bacillus cereus, Escherichia coli, Staphylococcus aureus, and MRSA. The strains exhibited similar growth rates at 0-5% NaCl, with approximate reduction in growth rate observed at 9% NaCl. Weissella sp. S1, S2, and S3 exhibited maximum growth rates at pH 7, 9, and 8, respectively. The crude bacteriocin was prepared from Weissella sp. S3 and subjected to characterization. The remaining activities after 30 min of exposure at each temperature were 100%, beyond 75%, and 49% at 4℃ and 37℃, 50℃ and 70℃, and 100℃, respectively. The remaining activities after 24 h of exposure at each pH were 100%, 75%, and 49% at pH 3 and 5, 7 and 9, and 10, respectively. Use of 50% (v/v) ethanol or isopropanol treatment did not diminish the antibacterial activity of the bacteriocin, while the 50% (v/v) hexane treatment reduced the activity by 51%. The molecular weight of the bacteriocin was nearly 6 kDa that was quantified using tricine-SDS-PAGE. Our findings suggest that Weissella sp. S3 may be considered a probiotic and useful source of antimicrobial substances in the development of bio-preservatives for food or in MRSA treatment.

• Clinics in Orthopedic Surgery
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• v.10 no.4
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• pp.427-432
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• 2018

Background: The purpose of this study was to evaluate the usefulness of sonication technique for microbiological diagnosis and the sterility of the recycled autoclaved femoral components from infected total knee arthroplasty (TKA) using a sonication method. Methods: Nineteen femoral implants explanted from patients with infected TKA were sterilized with a standard autoclave method. Standard culture of the fluid before and after sonication of the sterilized implants was performed to detect pathogenic microorganisms. Additional experiments were performed to evaluate the sterility of the recycled implant by inducing artificial biofilm formation. Methicillin-resistant Staphylococcus aureus (MRSA) was inoculated into 10 implants and sterilization in a standard autoclave was performed, and then the fluid was cultured before and after sonication. Results: Two of the 19 sterilized implants were positive for growth of bacteria after sonication, whereas no growth was detected in the cultured fluid from the sterilized implants before sonication. The bacteria were Staphylococcus species in all two cases. In one of 10 implants inoculated with MRSA, the culture was positive for growth of bacteria both before and after sonication. However, Staphylococcus epidermidis was cultured from both occasions and thus this implant was thought to be contaminated. Conclusions: We found sonication for identification of pathogens could be helpful, but this finding should be interpreted carefully because of the possibility of contamination. Sterilization of an infected femoral implant with an autoclave method could be a good method for using the temporary articulating antibiotic spacer in two-stage revision arthroplasty.

• Archives of Plastic Surgery
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• v.48 no.2
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• pp.165-174
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• 2021

Background In recent years, implant-based breast reconstruction has been performed because of its simplicity, short operation time, and rapid recovery of patients. Several studies have reported treatment methods for implant surgery-related infection, which is a serious complication. The aim of this study was to introduce our strategy for salvaging infected implants and to evaluate its effectiveness. Methods The authors performed a retrospective study of 145 cases from 132 patients who underwent implant-based breast reconstruction from January 2012 to December 2018. Empirical antibiotics were immediately administered to patients with suspected infections. The patients then underwent salvage treatment including appropriate antibiotics, ultrasonography-guided aspiration, debridement, antibiotic lavage, and implant exchange through a multidisciplinary approach. Patient demographics, operative data, duration until drain removal, adjuvant treatment, and complications were analyzed. Results The total infection rate was 5.5% (8/145). A longer indwelling catheter period and adjuvant treatment were significantly associated with infection. The salvage treatment showed a success rate of 87.5% (7/8). Seven patients who received early aggressive salvage treatment recovered from infection. One patient with methicillin-resistant Staphylococcus aureus, who received salvage treatment 11 days after symptom onset, did not respond to drainage and antibiotic treatment. That patient subsequently underwent explantation. Conclusions In implant-based breast reconstruction, prevention of infection is of the utmost importance. However, if an infection is suspected, proactive empirical antibiotic therapy and collaboration with the necessary departments are required. Through a multidisciplinary approach and proactive early management, swift and appropriate salvage should be performed.

• Biomedical Science Letters
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• v.27 no.4
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• pp.323-328
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• 2021

Naegleria fowleri is a free-living amoeba causing primary amoebic encephalitis. In this study, we analyzed how the N-aceytlglucosamine (GlcNAc) and D-galactose affected the interaction between Naegleria fowleri and methicillin-resistant Staphylococcus aureus (MRSA) or Escherichia coli O157:H7, and the interaction with bacteria when monosaccharides were treated with N. fowleri for a longer pre-incubation time. When GlcNAc was treated with N. fowleri for 1 hr, the E. coli association was almost the same as that of the control not treated with GlcNAc until the concentration of GlcNAc was 25 mM. However, the E. coli association was reduced by approximately 91% with 100 mM GlcNAc. E. coli invasion into N. fowleri showed statistical significance only in the group treated with 100 mM GlcNAc. The interaction when treated with galactose showed a very different pattern in the 50 mM galactose group than when treated with GlcNAc. In the MRSA interaction, a statistically significant decrease in association (76.3% by GlcNAc and 88.7% by galactose) and invasion (3.6% by GlcNAc and 9.3% by galactose) was shown by the concentration of two 100 mM monosaccharides. The group treated with monosaccharides at the same time showed almost no difference in all interactions from the group treated with monosaccharides at the same time. Taken together, it suggested that the effect of monosaccharides on the interaction of several Gram-negative or positive bacteria and the evidence that the interaction could be enhanced by longer pre-incubation time.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.4
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• pp.321-331
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• 2021

Vancomycin, an antibiotic used occasionally as a last line of treatment for methicillin-resistant Staphylococcus aureus, is reportedly associated with nephrotoxicity. This study aimed at evaluating the protective effects of lutein against vancomycin-induced acute renal injury. Peroxisome proliferator-activated receptor gamma (PPARγ) and its associated role in renoprotection by lutein was also examined. Male BALB/c mice were divided into six treatment groups: control with normal saline, lutein (200 mg/kg), vancomycin (250 mg/kg), vancomycin (500 mg/kg), vancomycin (250 mg/kg) with lutein, and vancomycin (500 mg/kg) with lutein groups; they were euthanized after 7 days of treatment. Thereafter, samples of blood, urine, and kidney tissue of the mice were analyzed, followed by the determination of levels of N-acetyl-β-D-glucosaminidase (NAG) in the urine, renal creatine kinase; protein carbonyl, malondialdehyde, and caspase-3 in the kidney; and the expression of PPARγ, nuclear factor erythroid 2-related factor 2 (Nrf2), and nuclear factor-kappaB (NF-κB) in renal tissue. Results showed that the levels of protein carbonyl and malondialdehyde, and the activity of NAG, creatine kinase and caspase-3, were significantly increased in the vancomycin-treatment groups. Moreover, the levels of Nrf2 significantly decreased, while NF-κB expression increased. Lutein ameliorated these effects, and significantly increased PPARγ expression. Furthermore, it attenuated vancomycin-induced histological alterations such as, tissue necrosis and hypertrophy. Therefore, we conclude that lutein protects against vancomycin-induced renal injury by potentially upregulating PPARγ/Nrf2 expression in the renal tissues, and consequently downregulating the pathways: inflammation by NF-κB and apoptosis by caspase-3.

• 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.