• 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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5644-5651
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• 2014

Propolis is an extremely safe natural antimicrobial substance that has been reported to have powerful antibacterial efficacy. The aim of this study was to evaluate the inhibitory effects of propolis against Candida albicans (C. albicans). Propolis was collected from the honey bee Apis mellifera. The strain of C. albicans was cultivated overnight in liquid media incubated at $37^{\circ}C$. The antimicrobial activity was investigated using phosphate buffered saline (PBS), 3% sodium hypochlorite (NaOCl), 0.1% chorhexidine (CHX), and propolis extracts ($5{\mu}l/ml$, $10{\mu}l/ml$). C. albicans were sensitive to 3% NaOCl, 0.1% CHX, and propolis ($5{\mu}l/ml$, $10{\mu}l/ml$) with zones of inhibition of 15, 14.5, 16, and 17 mm, respectively. The CFU of PBS, 3% NaOCl, 0.1% CHX, $5{\mu}l/ml$ and $10{\mu}l/ml$ of propolis led a 1, 7, 7, 5 and 7-log reduction. Among the groups tested, C. albicans was most sensitive to $10{\mu}l/ml$ of propolis, which showed the largest inhibition zones. Therefore, propolis can be a new antimicrobial therapy for oral mucosa disease in traditional medicine.

• Korean Journal of Veterinary Research
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• v.40 no.4
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• pp.763-767
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• 2000

This study was performed to isolate and identify bacteria from uterus with pyometra and examine their susceptibility to antimicrobial agents. Uterus of 16 bitches with pyometra were surgically removed by ovariohysteroctomy and then bacteria were isolated and identified. Also, susceptibility test to 15 antimicrobial agents was performed. Out of 16 bitches, 11 strains of Escherichia coli, 2 strains of Serratia marcescens, and 1 strain of Staphylococcus aureus and Salmonella spp. were identified. In antimicrobial susceptibility test, the majority of isolates were susceptible to enrofloxacin, norfloxacin, chloramphenicol, nalidixic acid, gentamicin, trimethprim-sulfamethazole, tetracycline, and moderately susceptible to carbenicillin, amikacin, ampicillin, neomycin, but resistant to vancomycin, streptomycin, bacitracin and colistin. In conclusion, E coli was the most common bacteria isolated from bitches with pyometra and those susceptible antimicrobial agents could be recommended to medical therapy of pyometra.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.4
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• pp.239-248
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• 2022

The taxonomy of bacteria in the field of clinical microbiology is in a state of constant flux. A large-scale revamping of the classification and nomenclature of anaerobic bacteria has taken place over the past few decades, mainly due to advances in molecular techniques such as 16S rRNA and whole genome sequencing (WGS). New genera and species have been added, and existing genera and species have been reclassified or renamed. A major role of the clinical microbiological laboratories (CMLs) is the accurate identification (ID) and appropriate antimicrobial susceptibility testing (AST) for clinically important bacteria, and rapid reporting and communication of the same to the clinician. Taxonomic changes in anaerobic bacteria could potentially affect the choice of appropriate antimicrobial agents and the antimicrobial breakpoints to use. Furthermore, current taxonomy is important to prevent treatment failures of emerging pathogenic anaerobes with antimicrobial resistance. Therefore, CMLs should periodically update themselves on the changes in the taxonomy of anaerobic bacteria and suitably inform clinicians of these changes for optimum patient care. This article presents an update on the taxonomy of clinically important anaerobic bacteria, together with the previous names or synonyms. This taxonomy update can help guide antimicrobial therapy for anaerobic bacterial infections and prevent treatment failure and can be a useful tool for both CMLs and clinicians.

• Tuberculosis and Respiratory Diseases
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• v.59 no.5
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• pp.522-529
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• 2005

Background : Several national societies have published guidelines for empirical antimicrobial therapy in patients with severe community-acquired pneumonia (SCAP). This study investigated the etiologies of SCAP in the Asan Medical Center and assessed the relationship between the initial empirical antimicrobial regimen and 30 day mortality rate. Method : retrospective analysis was performed on patients with SCAP admitted to the ICU between March 2002 and February 2004 in the Asan Medical Center. The basic demographic data, bacteriologic study results and initial antimicrobial regimen were examined for all patients. The clinical outcomes including the ICU length of stay, the ICU mortality rate, and 30 days mortality rates were assessed by the initial antimicrobial regimen. Results : One hundred sixteen consecutive patients were admitted to the ICU (mean age 66.5 years, 81.9 % male, 30 days mortality 28.4 %). The microbiologic diagnosis was established in 58 patients (50 %). The most common pathogens were S. pneumoniae (n=12), P. aeruginosae (n=9), K. pneumonia (n=9) and S. aureus (n=8). The initial empirical antimicrobial regimens were classified as: ${\beta}$-lactam plus macrolide; ${\beta}$-lactam plus fluoroquinolone; anti-Pseudomonal ${\beta}$-lactam plus fluoroquinolone; Aminoglycoside combination regimen; ${\beta}$-lactam plus clindamycin; and ${\beta}$-lactam alone. There were no statistical significant differences in the 30-day mortality rate according to the initial antimicrobial regimen (p = 0.682). Multivariate analysis revealed that acute renal failure, acute respiratory distress syndrome and K. pneumonae were independent risk factors related to the 30 day mortality rate. Conclusion : S. pneumoniae, P. aeruginosae, K. pneumonia and S. aureus were the most common causative pathogens in patients with SCAP and K. pneumoniae was an independent risk factor for 30 day mortality. The initial antimicrobial regimen was not associated with the 30-day mortality.

• Tuberculosis and Respiratory Diseases
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• v.67 no.4
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• pp.281-302
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• 2009

The successful treatment of community-acquired pneumonia requires appropriate, empirical antimicrobial therapy. The etiology and antimicrobial susceptibility of major pneumonia pathogens can differ by country. Therefore, the ideal treatment guidelines for community-acquired pneumonia should be based on the studies performed in each country. We developed a treatment guideline for community-acquired pneumonia for immunocompetent adults in Korea. This guideline was developed by the joint committee of the Korean Society for Chemotherapy, the Korean Society of Infectious Diseases, and the Korean Academy of Tuberculosis and Respiratory diseases.

• Tuberculosis and Respiratory Diseases
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• v.51 no.1
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• pp.17-24
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• 2001

Background : Community-acquired pneumonia(CAP) remains a leading cause of morbidity and mortality worldwide. Recently, the evolution of drug-resistant microorganisms has become a serious problem in CAP management. Specific antimicrobial therapy is the cornerstone of CAP management. However, obtaining an accurate etiologic diagnosis clinically is not easy and empirical antimicrobial treatment is usually administered prior to the correct microbiologic diagnosis. In this study, the clinical usefulness of empirical CAP treatment was investigated. Methods : A total 35 cases were studied prospectively over a 16-month period in Mokpo Catholic Hospital from Dec. 1995 to Mar. 1997. The microbiologic diagnosis was made by sputum, blood culture, a specific serum antibody test and an immunologic study. Results : The causative organisms were isolated in 10 (30%) out of 33 cases: 8 cases and 1 case on the sputum culture and blood culture respectively, and 1 case by an indirect hemagglutinin test. 12 cases had underlying diseases: pulmonary tuberculosis 4, alcoholism 4, diabetes mellitus 3, and liver cirrhosis 1. Antimicrobial treatment was given empirically and all cases recovered. Conclusion : A definite microbiologic diagnosis before commencing the appropriate treatment in CAP is not straightforward. Empirical therapy according to a clinical assessment is important and helpful. However, every effort to make the correct etiologic diagnosis should be taken.

• Tuberculosis and Respiratory Diseases
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• v.67 no.3
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• pp.212-220
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• 2009

Background: Ventilator-associated pneumonia caused by multi-drug resistant Acinetobacter baumannii has been increasing and growing as a threat in intensive care units. Limited therapeutic options have forced clinicians to choose colistin with or without combination of other antibiotics. We tried to compare the effectiveness between colistin monotherapy and combination therapy based on in vitro synergistic tests. Methods: From January 2006 to December 2007 in medical ICU of a tertiary care hospital in Korea, We reviewed the medical records of patients treated with intravenous colistin due to ventilator-associated pneumonia caused by multi-drug resistant Acinetobacter baumannii. Results: A total of 41 patients were analyzed. 22 patients had been treated with colistin monotherapy and 19 patients with colistin and combination antibiotics that were found to have in vitro synergistic effects. Baseline characteristics were similar in both groups but the mean duration of colistin administration was significantly longer in the combination group (19.1${\pm}$11.2 days vs. 12.3${\pm}$6.8 days, p=0.042). There were no significant differences in outcome variables between the two groups. Conclusion: Combination treatment based on the in vitro antimicrobial synergy test did not show better outcomes compared with colistin monotherapy in VAP caused by multi-drug resistant A. baumannii.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.1
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• pp.6-10
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• 2015

Photodynamic therapy (PDT) apply photosensitizers and light. The purpose of this study was to evaluate the in vitro efficacy of PDT using blue LED (light emitting diode) with photofrin and radachlorin for Propionibacterium acnes. The colony forming units method was used to assess the antibacterial activity. Suspension (1 mL) containing P. acnes at $1{\times}10^5CFU/mL$ were prepared and then 2 fold serial diluted to $12.5{\mu}g/mL$ from $50{\mu}g/mL$ concentration of photofrin and radachlorin. After 60 minutes incubation, light was irradiated for 10 to 30 minutes using the following light source of wavelength 460 nm, each energy density 36, 72 and $108J/cm^2$. Bacterial growth was evaluated after 72 hours incubation in a Phenylethanol Blood Agar (PEBA) culture. In addition, flow cytometric analysis were performed to measure the live cell after PDT. Also transmission electron microscopy (TEM) was employed to evaluate the effect of pathogens by PDT. The PDT Group was perfectly killed to all kind of photosensitizers dose of $12.5{\mu}g/mL$ with irradiation of 10 minutes. Also other Groups were killed to all kind of photosensitizers dose of $6.25{\mu}g/mL$ with irradiation time of 20 and 30 minutes. The flow cytometry showed a lower number of viable bacteria in the PDT group compared to the control group. The images of the TEM results were showed in cytoplasmic membrane damage and partially deformed to cell morphologies. These results suggest that radachlorin and photofrin combine blue LED PDT can be effectively treated when was proved treatment for acnes therapy.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.5
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• pp.490-496
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• 2000

We have conducted a retrospective study of 224 patients with the diagnosis of oral and maxillofacial infection who had been treated between 1988 and 1999 at Gyeong-Sang National University Hospital. This study was aimed to furnish the data of oral and maxillofacial infection and to aid diagnosis and treatment. The most common fascial space involved, as determined by clinical, radiologic, and operative findings, were the submandibular space(39.4%). The most frequent cause of oral and maxillofacial infection was odontogenic 68.8%. In the odontogenic cause, dental caries was the most common cause. Two-hundred three patients required surgical drainage of the abscess. Seventeen patients needed tracheostomy for airway control. The overall mortality was 0.9% despite aggressive anti-microbial therapy and early surgical intervention. All other patients had an uneventful recovery without major complication except osteomyelitis case(6.0%). The combination of early radiologic diagnosis, effective antimicrobial therapy, and intensive surgical management contributed to the good prognosis.