• 제목/요약/키워드: Antimicrobial test

검색결과 803건 처리시간 0.023초

오죽 잎 용매분획물의 항산화 및 항균 활성 (Antioxidant and antimicrobial activity of solvent fractions from black bamboo leaves)

  • 배현경;정신교
    • 한국식품저장유통학회지
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    • 제21권4호
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    • pp.560-564
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    • 2014
  • 오죽 잎의 메탄올 조추출물을 극성에 따라 용매분획하고 분획물의 항산화 활성과 항산화 활성, S. aureus 균주에 대한 항균활성을 조사하고 활성성분을 HPLC를 이용하여 정량하였다. 용매분획물 중에서 ethyl acetate 분획물의 DPPH radical 소거 활성, FRAP활성이 모두 가장 강하였으며, 총페놀성 화합물의 함량도 가장 높았다. S. aureus 균주에 대한 항균활성 역시 ethyl acetate 분획물이 모든 시험 농도에서 가장 높은 활성을 보였다. Ethyl acetate 분획물 중에서 caffeic acid, ferulic acid, quercetin, kaempferol 성분을 분리하여 정량하였으며 이 중 kaempferol의 함량이 가장 높았다. 오죽 잎의 ethyl acetate 분획물은 천연 식품보존료로서 활용이 가능할 것으로 보인다.

Modified Pharmacokinetic/Pharmacodynamic model for electrically activated silver-titanium implant system

  • Tan, Zhuo;Orndorff, Paul E.;Shirwaiker, Rohan A.
    • Biomaterials and Biomechanics in Bioengineering
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    • 제2권3호
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    • pp.127-141
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    • 2015
  • Silver-based systems activated by low intensity direct current continue to be investigated as an alternative antimicrobial for infection prophylaxis and treatment. However there has been limited research on the quantitative characterization of the antimicrobial efficacy of such systems. The objective of this study was to develop a semi-mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model providing the quantitative relationship between the critical system parameters and the degree of antimicrobial efficacy. First, time-kill curves were experimentally established for a strain of Staphylococcus aureus in a nutrientrich fluid environment over 48 hours. Based on these curves, a modified PK/PD model was developed with two components: a growing silver-susceptible bacterial population and a depreciating bactericidal process. The test of goodness-of-fit showed that the model was robust and had good predictability ($R^2>0.7$). The model demonstrated that the current intensity was positively correlated to the initial killing rate and the bactericidal fatigue rate of the system while the anode surface area was negatively correlated to the fatigue rate. The model also allowed the determination of the effective range of these two parameters within which the system has significant antimicrobial efficacy. In conclusion, the modified PK/PD model successfully described bacterial growth and killing kinetics when the bacteria were exposed to the electrically activated silver-titanium implant system. This modeling approach as well as the model itself can also potentially contribute to the development of optimal design strategies for other similar antimicrobial systems.

The Evolving Epidemiology of Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Strains Isolated from Adults in Crete, Greece, 2009-2016

  • Maraki, Sofia;Mavromanolaki, Viktoria Eirini;Stafylaki, Dimitra;Hamilos, George;Samonis, George
    • Infection and chemotherapy
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    • 제50권4호
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    • pp.328-339
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    • 2018
  • Background: Pneumococcal disease is a major cause of morbidity and mortality worldwide, especially in patients with comorbidities and advanced age. This study evaluated trends in epidemiology of adult pneumococcal disease in Crete, Greece, by identifying serotype distribution and antimicrobial resistance of consecutive Streptococcus pneumoniae strains isolated from adults during an 8-year time period (2009-2016) and the indirect effect of the infant pneumococcal higher-valent conjugate vaccines 10-valent pneumococcal conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13). Materials and Methods: Antimicrobial susceptibility was performed by E-test and serotyping by Quellung reaction. Multidrug resistance (MDR) was defined as non-susceptibility to penicillin (PNSP) combined with resistance to ${\geq}2$ non-${\beta}$-lactam antimicrobials. Results: A total of 135 S. pneumoniae strains were isolated from adults during the study period. Twenty-one serotypes were identified with 17F, 15A, 3, 19A, and 11A, being the most common. The coverage rates of PCV10, and PCV13 were 17.8% and 37.8%, respectively. PCV13 serotypes decreased significantly from 68.4% in 2009 to 8.3% in 2016 (P = 0.002). The most important emerging non-PCV13 serotypes were 17F, 15A, and 11A, with 15A being strongly associated with antimicrobial resistance and MDR. Among all study isolates, penicillin-resistant and MDR strains represented 7.4% and 14.1%, respectively. Predominant PNSP serotypes were 19A (21.7%), 11A (17.4%), and 15A (17.4%). Erythromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, and levofloxacin resistant rates were 30.4%, 15.6%, 16.3%, 16.3%, and 1.5%, respectively. Conclusion: Although pneumococcal disease continues to be a health burden in adults in Crete, our study reveals a herd protection effect of the infant pneumococcal higher-valent conjugate vaccination. Surveillance of changes in serotype distribution and antimicrobial resistance among pneumococcal isolates are necessary to guide optimal prevention and treatment strategies.

Molecular characteristics of Escherichia coli from bulk tank milk in Korea

  • Yoon, Sunghyun;Lee, Young Ju
    • Journal of Veterinary Science
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    • 제23권1호
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    • pp.9.1-9.11
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    • 2022
  • Background: Escherichia coli, which causes subclinical or clinical mastitis in cattle, is responsible for transmitting antimicrobial resistance via human consumption of raw milk or raw milk products. Objectives: The objective of this study was to investigate the molecular characteristics of 183 E. coli from bulk tank milk of five different dairy factories in Korea. Methods: The molecular characteristics of E. coli such as serogroup, virulence, antimicrobial resistance, and integron genes were detected using polymerase chain reaction and antimicrobial susceptibility were tested using the disk diffusion test. Results: In the distribution of phylogenetic groups, group D was the most prevalent (59.6%) and followed by group B1 (25.1%). The most predominant serogroup was O173 (15.3%), and a total of 46 different serotypes were detected. The virulence gene found most often was fimH (73.2%), and stx1, fimH, incC, fyuA, and iutA genes were significantly higher in isolates of phylogenetic group B1 compared to phylogenetic groups A, B2, and D (p < 0.05). Among 64 E. coli isolates that showed resistance to at least one antimicrobial, the highest resistance rate was observed for tetracyclines (37.5%). All 18 integron-positive E. coli carried the integron class I (int1) gene, and three different gene cassette arrangements, dfrA12+aadA2 (2 isolates), aac(6')-Ib3+aac(6')-Ib-cr+aadA4 (2 isolates), and dfrA17+aadA5 (1 isolate) were detected. Conclusions: These data suggest that the E. coli from bulk tank milk can be an indicator for dissemination of antimicrobial resistance and virulence factors via cross-contamination.

Diagnosis of Subclinical Mastitis-Causing Pathogens Using MALDI-TOF Mass Spectrometry in a Certified Organic Dairy Farm in Korea

  • Sung Jae Kim;Hyun-Tae Kim;Yo-Han Kim
    • 한국임상수의학회지
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    • 제40권6호
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    • pp.393-398
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    • 2023
  • We identified mastitis-causing pathogens using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) in an organic dairy farm and evaluated the effects of antimicrobial restriction on antimicrobial susceptibility. A total of 43 Holstein cows without any clinical sign of mastitis were used in this study, and 172 quarter milk samples were cultured on blood agar plates for 24 hours at 37℃. Subsequently, bacterial species were identified and antimicrobial susceptibility tests were performed. The subclinical mastitis infection rates in the cows and quarters were 58.1% (25/43) and 25.6% (44/172), respectively. In the species identification, Staphylococcus aureus (40.9%) was the most prominent isolate, followed by S. chromogenes (22.7%), S. epidermis (18.2%), S. simulans (11.4%), S. haemolyticus (2.3%), S. muscae (2.3%), and S. xylosus (2.3%). In the antimicrobial susceptibility test, all isolates were 100% susceptible to 24 of 28 antibiotics, except for benzylpenicillin, cefalotin, cefpodoxime, and trimethoprim/sulfamethoxazole. The resistance rates of S. aureus, S. chromogenes, and S. muscae isolates to trimethoprim/sulfamethoxazole were 27.8%, 10%, and 100%, respectively, and the resistance rates of S. epidermis and S. xylosus to benzylpenicillin were 50% and 100%, respectively. S. chromogenes, S. epidermis, S. simulans, S. haemolyticus, and S. xylosus were resistant to cefalotin and cefpodoxime. In conclusion, restrictions on antimicrobial use for organic dairy farm certification have resulted in a high Staphylococcus spp. infection rate. Therefore, our study indicates the importance of mastitis management strategies implemented by farmers together with veterinary practitioners, even if mastitis does not appear clinically in organic dairy farms.

돼지 폐렴병소에서 분리한 Pasteurella multocida의 특성 및 항생제 감수성 양상 (Characteristics and Antimicrobial Susceptibility Patterns of Pasteurella multocida Isolated from Pneumonic Lung Lesions of Swine)

  • 손준형;최성균;조길재
    • 생명과학회지
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    • 제19권5호
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    • pp.615-619
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    • 2009
  • 영남지방 5개 농장에서 사육중인 돼지 251두의 폐렴병소로부터 P. multocida를 분리한 결과 91주의 P. multocida가 분리되어 분리율은 36.3%로 나타났다. 생화학적 특성을 조사한 후 PCR로 최종 확인한 결과 P. multocida species-specific 유전자 460 bp의 특이 증폭산물을 관찰하였다. 분리균 91주의 P. multocida에 대한 약제 감수성 검사 결과 amikacin (91.2%), cephalothin (87.9%), cefoxitin (84.6%), florofenicol (93.4%), norfloxacin (65.9%), ofloxacin (80.2%) 등의 약제에 비교적 높은 감수성을 나타내었다. 또한 대부분의 분리주는 5종 이상의 약제에 대해 다재 내성 양상을 나타내었다.

심한 근관 감염에서의 항생제 선택 (Antimicrobial choice of severe endodontic infection)

  • 조주연;하정홍;진명욱;김영경;김성교
    • 대한치과의사협회지
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    • 제52권7호
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    • pp.425-431
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    • 2014
  • Objectives : The purpose of our study was to evaluate penicillin as a still drug of choice for severe endodontic infection, by analyzing the antimicrobial susceptibilities from endodontic infections with swelling to figure out appropriate antibiotics as empirical treatment. Materials and methods : This study involved 18 patients who attended for emergency treatment because of facial or periapical swelling associated with root canal infections. Identification and antimicrobial susceptibility test of each pathogen were performed by Vitek2 Systems (bioM$\acute{e}$rieux, Marcy l'Etoile, France). Results : The most frequent bacteria was Streptococcus spp.(77%), and the resistance against penicillin was 35% in overall patients, followed by clindamycin and erythromycin (17%), which was much higher than previous studies. Conclusions : In our study, the higher resistance made penicillin alone not to be chosen as the first antibiotic drug for severe endodontic infections. Combinations with other drug, penicillin with wider spectrum of activity, or changing to other antibiotics was considered while remembering the increased risk of resistant microorganism.

Reuse of Oyster Shell Waste as Antimicrobial Water Treatment Agent by Silver Ion Exchange

  • Jo, Myung-Chan;Byeong-II Noh;Shin, Choon-Hwan
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • 제4권3호
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    • pp.185-193
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    • 2000
  • A water treatment agent with antimicrobial activity(Ag-Os) was created by exchanging silver ion($Ag^{+}$) on calcined oyster shell powder. The desorption of the exchanged silver ion was negligible, thereby indicating a stable antimicrobial water treatment agent. The sterilization effect of Ag-Os on underwater microorganisms was then investigated. An MIC (Minimum Inhibitory Concentration) test result indicated that Ag-Os had an excellent sterilization effect on G-germs, such as Escherichia coli and Pseudomonas aeruginosa. Most germs were annihilated with an Ag-Os concentration of 200 ppm and contact time of 60 minutes. The sterilization effect was mainly dependent on the contact time. The zeta potential of the Ag-Os powder adsorbed on sand was measured relative to the concentration of exchanged silver ion. As the concentration of the exchanged silver ion increased, the surface charge density of the anions on the surface of the Ag-Os powder adsorbed on sand also increased. Accordingly, this result indicated that a higher silver ion than ion exchange capacity was present on the particle surface due to adsorption. Consequently, this increased concentration of exchanged silver ion would appear to significantly enhance the sterilization power.

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산수유 헥산 추출물의 항균효과 및 세포독성 (Screening of Cytotoxicity and Antimicrobial Effects of Hexane Extracts from Cornis fructus)

  • 천현자;최원형;이정호;양현옥;백승화
    • 동의생리병리학회지
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    • 제17권2호
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    • pp.476-480
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    • 2003
  • Cornis fructus was extracted by successive extraction and then fractionated with hexane extract to get active fractions. This study was performed to determine the cytotoxic effect of hexane extract from Cornis fructus on NIH 3T3 fibroblasts and cancer cell lines using MTT assay. Hexane extract showed cytotoxic effect against A549, B16 melanoma and MDA-MB-231. Futher fractionation with hexane extract was performed to obtain effective fraction, fraction 3 showed the cytotoxic effect against A549 and MDA-MB-231. In antimicrobial test of each fraction of hexane extract, fraction 5 showed antimicrobial activities against P. putida and P. aeruginosa.

Antimicrobial Activity of Methyl Gallate isolated from the Leaves of Glochidion superbum Against Hospital Isolates of Methicillin Resistant Staphylococcus aureus

  • Ahmed, Mohammed Dahiru;Taher, Muhammad;Maimusa, Alhaji Hamusu;Rezali, Mohamad Fazlin;Mahmud, Mohammed Imad Al-deen Mustafa
    • Natural Product Sciences
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    • 제23권1호
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    • pp.5-8
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    • 2017
  • An antimicrobial compound has been isolated from the leaves of Glochidion superbum. The compound was determined as methyl 3, 4, 5-trihydroxybenzoate (methyl gallate), based on ultraviolet (UV), infrared (IR), nuclear magnetic resonance (NMR) and mass spectroscopy (MS) analysis. The isolated compound exhibited potent antimicrobial activity against three clinical isolates of methicillin resistant Staphylococcus aureus (MRSA) by qualitative agar disc diffusion method and quantitative broth dilution method. Agar disc diffusion was done in a dose-dependent manner for each bacterial isolate at disc potencies of 25, 50, 100, and $150{\mu}g/disc$. The zones of inhibition were on average equal to 12.27, 14.20, 15.43, and 24.17 mm respectively. The inhibition zones were compared with that of vancomycin disc at $30{\mu}g$ as a reference standard. The MIC and MBC values were $50{\mu}g/ml$ and $100{\mu}g/ml$ respectively. The results of anti MRSA activity were analyzed using one-way ANOVA with Turkey's HSD and Duncan test. In conclusion, methyl gallate which was isolated from G. superbum showed the inhibition activity against methicillin resistant S. aureus.