• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.301-310
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• 2010

Bacillus subtilis strains produce a broad spectrum of bioactive peptides. The lipopeptide surfactin belongs to one well-known class, which includes amphiphilic membrane-active biosurfactants and peptide antibiotics. Both the srfA promoter and the ComP-ComA signal transduction system are an important part of the factor that results in the production of surfactin. Bs-M49, obtained by means of low-energy ion implantation in wild-type Bs-916, produced significantly lower levels of surfactin, and had no obvious effects against R. solani. Occasionally, we found strain Bs-M49 decreased spore formation and the development of competence. Blast comparison of the sequences from Bs-916 and M49 indicate that there is no difference in the srfA operon promoter PsrfA, but there are differences in the coding sequence of the comA gene. These differences result in three missense mutations within the M49 ComA protein. RT-PCR analyses results showed that the expression levels of selected genes involved in competence and sporulation in both the wild-type Bs-916 and mutant M49 strains were significantly different. When we integrated the comA ORF into the chromosome of M49 at the amyE locus, M49 restored hemolytic activity and antifungal activity. Then, HPLC analyses results also showed the comA-complemented strain had a similar ability to produce surf actin with wild-type strain Bs-916. These data suggested that the mutation of three key amino acids in ComA greatly affected the biological activity of Bacillus subtilis. ComA protein 3D structure prediction and motif search prediction indicated that ComA has two obvious motifs common to response regulator proteins, which are the N-terminal response regulator receiver motif and the C-terminal helix-turn-helix motif. The three residues in the ComA N-terminal portion may be involved in phosphorylation activation mechanism. These structural prediction results implicate that three mutated residues in the ComA protein may play an important role in the formation of a salt-bridge to the phosphoryl group keeping active conformation to subsequent regulation of the expression of downstream genes.

• Journal of Korean Neurosurgical Society
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• v.50 no.4
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• pp.332-340
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• 2011

Objective : Pyogenic spondylitis often results in acute neurological deterioration requiring adequate surgical intervention and appropriate antibiotic treatment. The purpose of this study was to conduct an analysis of the clinical effect of continuous irrigation via laminotomy in a series of patients with pyogenic spondylitis in thoracic and lumbar spine. Methods : The authors conducted a retrospective investigation of 31 consecutive patients with pyogenic thoracic and lumbar spondylitis who underwent continuous irrigation through laminotomy from 2004 to 2008. The study included 22 men and 9 women, ranging in age from 38 to 78 years (mean 58.1 years). The average follow-up duration was 13.4 months (range, 8-34 months). We performed debridement and abscess removal after simple laminotomy, and then washed out epidural and disc space using a continuous irrigation system. Broad spectrum antibiotics were administered empirically and changed according to the subsequent culture result. Clinical outcomes were based on the low back outcome scale (LBOS), visual analogue scale (VAS) score, and Frankel grade at the last follow-up. Radiological assessment involved plain radiographs, including functional views. Results : Common predisposing factors included local injection for pain therapy, diabetes mellitus, chronic renal failure, and liver cirrhosis. Causative microorganisms were identified in 22 cases (70.9%) : Staphylococcus aureus and Streptococcus spp. were the main organisms. After surgery, LBOS, VAS score, and Frankel grade showed significant improvement in most patients. Spinal stability was maintained during the follow-up period, making secondary reconstructive surgery unnecessary for all patients, except one. Conclusion : Simple laminotomy with continuous irrigation by insertion of a catheter into intervertebral disc space or epidural space was minimally invasive and effective in the treatment of pyogenic spondylitis. This procedure could be a beneficial treatment option in patients with thoracolumbar spondylitis combined with minimal or moderate destructive change of vertebrae.

• Journal of Yeungnam Medical Science
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• v.16 no.2
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• pp.219-227
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• 1999

Background: In contrast to a healthy person, patients who have acute lower respiratory tract infection with underlying pulmonary diseases have various pathogens, a rapidly progressive downhill course, and a poor response to prior antimicrobial therapy. Broad spectrum antibacterial therapy is needed for full evaluation. Materials and Methods: To evaluate the efficacy and safety of cefpirome, we administered 1gm cefpirome, twice a day to 30 patients, who had signs and symptoms of acute lower respiratory infection regardless of their underlying disease, except to those who had an allergic history to antibiotics or severe systemic diseases. Results: The results were as follows: 1) Among 30 cases, 21 cases(70.0%) showed excellent improvement, and 7 cases(23.3%) showed good improvement in their symptoms and signs of acute lower respiratory infection. 2) In 14 cases with isolated pathogens, we observed bacteriologic eradication in 11 cases(78. 6%). 3) Significant side effects were not found. Conclusion: Above results suggest that cefpirome was effective as a monotherapy in patients with acute lower respiratory infection, especially on those with an underlying chronic obstructive pulmonary disease(COPD).

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.391-400
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• 2011

Pneumonia is an infection of the lungs and respiratory system and can be classified by a variety of factors such as infectious agents, etiology, infection area, and other criteria. From a 46-year-old male, who was suspected of being infected with atypical pathogen pneumonia and underwent such tests as serological testing, examination of sputum, urine examination, parasite examination, bronchoscopy, needle biopsy and so on, no significant abnormality was found. This patient also showed no specific symptoms like auscultatory abnormalities, high fever, nonproductive cough, muscle stiffness, sputum production, dyspnea. Prescription of broad-spectrum oral antibiotics and ant-parasitic didn't seem to be effective against bacterial and atypical pathogen. The patient's condition alternately repeated between natural cure and recurrence. The average healing process during which scarring, nodule recurrence and disappearance on the lungs happened was about 20 days. Chest radiography and chest high resolution computerized tomographic scans(HRCT scan) was performed to depict parenchymal aberrations and demarcate the extent and distribution of atypical pathogen pneumonia. As a result, chest radiography did not show the specific symptoms, whereas areas of opacity (seen as white) which represent consolidation were revealed in chest HRCT scan. This indicates that only chest radiography is not that useful for early diagnosis of atypical pathogen pneumonia in patients, since it can't show exactly what the symptom is because of the barriers such as diaphragm, liver, and spine. Therefore, it is desirable that chest HRCT should be used in the diagnosis to compare with the results of chest radiography. Here, report with literature investigations the case of recurrent atypical pathogen pneumonia.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.255-262
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• 2010

Strain BCNU 2001 was isolated from soil samples collected from Tea-baek Mountain area. The biochemical characteristics and 16S ribosomal RNA gene sequences of the isolate revealed that the strain belonged to the Pseudomonas aeruginosa. The supernatants had an antimicrobial effect on various kind of bacteria and fungi. Especially BCNU 2001 was able to greatly inhibit the growth of Micrococcus luteus, Proteus mirabilis, Proteus vulgaris, and Aspergillus niger, and its inhibition zone was measured as 18.5 mm against Micrococcus luteus, 19.0mm against Proteus mirabilis, 17.0mm against Proteus vulgaris, and 13.5 mm against Aspergillus niger, respectively. Hexane and dichloromethane extracts of BCNU 2001 exhibited significant activity against bacteria, and dichloromethane and ethylacetate extracts showed significant activity against fungi. Pseudomonas strain BCNU 2001 was also determined to have antimicrobial peptide against various microorganisms including Gram positive bacteria, Gram negative bacteria and fungi. The obtained results may provide preliminary support for the usefulness of Pseudomonas strain BCNU 2001.

• Tuberculosis and Respiratory Diseases
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• v.69 no.6
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• pp.469-473
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• 2010

Nocardia farcinia, an aerobic, gram-positive bacilli actinomycetes of the genus Nocardia, is an uncommon pathogen found in humans. The most common Nocardia infection sites are the lung, central nervous system, and skin. Even though hematogenous dissemination can occur, isolation of the organism from blood cultures is very rare. We report a case of Nocardia infection that was isolated on blood cultures. A 59-year-old male with a medical history that includes a liver transplantation 6-years prior due to hepatocellular carcinoma secondary to chronic hepatitis B, developed pneumonia and was transferred to Severance Hospital. At the time of admission, the patient's initial exam showed hypothermia, tachypnea, and hypotension. His chest radiograph showed severe pneumonia and a large abscess on left upper lobe. Under the presumptive diagnosis of bacterial pneumonia or other opportunistic infection, we started broad spectrum antibiotics. However, he developed Nocardia sepsis, rapidly deteriorated, and subsequently died.

• Journal of Life Science
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• v.29 no.1
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• pp.84-89
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• 2019

Previous screening of novel antibacterial agents revealed that some bacterial isolates exhibited antibiotic activity against both gram-positive and gram-negative bacteria and that they showed antibacterial activity, even against methicillin-resistant Staphylococcus aureus (MRSA). Among these isolates, one bacterial strain, BCNU 1204, was identified as Pseudomonas aeruginosa using phenetic and phylogenetic analysis, based on 16S ribosomal RNA gene sequences. The maximum productivities of antimicrobial substances of BCNU 1204 were obtained after being cultured at $35^{\circ}C$ and pH 7.0 for 4 d in King's medium B (KMB). Dichloromethane (DCM) and ethylacetate (EA) extracts of P. aeruginosa BCNU 1204 exhibited strong antimicrobial activity, particularly against gram-positive bacteria. The EA extracts exhibited broad-spectrum activity against antibiotic resistant strains. Fraction 5-2, was obtained by recycling preparative liquid chromatography (LC) and preparative thin-layer chromatography (TLC) and was identified as phenazine-1-carboxylic acid belonging to phenazines using gas chromatography and mass spectrometry (GC/MS). Its minimum inhibitory concentration (MIC) values were $25{\mu}g/ml$, $50{\mu}g/ml$, ${\geq}25{\mu}g/ml$, and ${\geq}50{\mu}g/ml$ for MRSA CCARM 3089, 3090, 3091, and 3095 strains, respectively. P. aeruginosa BCNU 1204 may be a potential resource for the development of anti-MRSA antibiotics. Additional research is required to identify the active substance from P. aeruginosa BCNU 1204.

• Journal of Veterinary Science
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• v.24 no.3
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• pp.44.1-44.17
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• 2023

Background: Antibiotic resistance is a significant public health concern around the globe. Antimicrobial peptides exhibit broad-spectrum and efficient antibacterial activity with an added advantage of low drug resistance. The higher water content and 3D network structure of the hydrogels are beneficial for maintaining antimicrobial peptide activity and help to prevent degradation. The antimicrobial peptide released from hydrogels also hasten the local wound healing by promoting epithelial tissue regeneration and granulation tissue formation. Objective: This study aimed at developing sodium alginate based hydrogel loaded with a novel antimicrobial peptide Chol-37(F34-R) and to investigate the characteristics in vitro and in vivo as an alternative antibacterial wound dressing to treat infectious wounds. Methods: Hydrogels were developed and optimized by varying the concentrations of crosslinkers and subjected to various characterization tests like cross-sectional morphology, swelling index, percent water contents, water retention ratio, drug release and antibacterial activity in vitro, and Pseudomonas aeruginosa infected wound mice model in vivo. Results: The results indicated that the hydrogel C proved superior in terms of cross-sectional morphology having uniformly sized interconnected pores, a good swelling index, with the capacity to retain a higher quantity of water. Furthermore, the optimized hydrogel has been found to exert a significant antimicrobial activity against bacteria and was also found to prevent bacterial infiltration into the wound site due to forming an impermeable barrier between the wound bed and external environment. The optimized hydrogel was found to significantly hasten skin regeneration in animal models when compared to other treatments in addition to strong inhibitory effect on the release of pro-inflammatory cytokines (interleukin-1β and tumor necrosis factor-α). Conclusions: Our results suggest that sodium alginate -based hydrogels loaded with Chol-37(F34-R) hold the potential to be used as an alternative to conventional antibiotics in treating infectious skin wounds.

• Pediatric Infection and Vaccine
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• v.30 no.1
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• pp.47-54
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• 2023

With the widespread use of broad-spectrum antibiotics in clinical practice, the emergence of multidrug-resistant (MDR) gram-negative bacteria has become a global problem. The MDR Pseudomonas aeruginosa infection is especially difficult to treat and increases mortality in critically ill patients. Ceftolozane-tazobactam (Zerbaxa^TM) is a fifth-generation cephalosporin and beta-lactamase inhibitor that has proved to be effective for treating complicated urinary tract infections and complicated intra-abdominal infections caused by MDR P. aeruginosa. Herein, we report the first case of pediatric hematologic cancer in Korea that was successfully treated for MDR P. aeruginosa bacteremia with Ceftolozane-tazobactam.

• Clinical and Experimental Pediatrics
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• v.45 no.7
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• pp.847-854
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• 2002

Purpose : Long term hospitalized infants in neonatal intensive care units(NICUs) are prone to systemic infection. It is important to differentiate systemic candidiasis from systemic bacterial infection early in the course. Thus, in this study, we have compared clinical characteristics of systemic candidiasis and systemic bacterial infection, in premature low birth weight infants. Methods : Retrospective chart review of the medical records of 20 patients with systemic candidiasis and 23 patients with systemic bacterial infection was performed. Results : Among the risk factors of systemic candidiasis, total parenteral nutrition(TPN), the use of broad spectrum antibiotics, central catheter insertion, endotracheal intubation and the use of H2 blockers were more frequent in neonates with systemic candidiasis than neonates with systemic bacterial infection. Apnea with bradycardia developed more frequently in neonates with systemic candidiasis compared with systemic bacterial infection(75% vs 39%). In laboratory findings at symptom onset, seven cases(35%) of systemic candidal infections and two cases(9%) of systemic bacterial infections showed leukopenia and thrombocytopenia(P=0.03). Blood was the most frequent isolation site of candida and bacteria. Conclusion : In neonates with systemic candidiasis, apnea with bradycardia, pneumonia and thrombocytopenia were prone to develop more frequently. The use of TPN, antibiotics and central catheters was strongly associated with systemic candidiasis. Empirical treatment with antifungal agent should be considered in critically ill neonates with above findings.