Antibacterial Activity of Zinc Oxide Nanoparticles in Self- Curing Acrylic Resin Against Streptococcus mutans

ABSTRACT: Antibacterial activity of zinc oxide nanoparticles in self-curing acrylic resin against Streptococcus mutans. The main objective of this study was to investigate whether nanoparticles of zinc oxide (ZnO) in self-curing acrylic resin, hav e antimicrobial properties against Streptococcus mutans, one of the microorganisms involved in the development of caries. Self- cured acrylic resin samples were prepared by incorporating ZnO nanoparticles at different concentrations based on the minimum inhibitory concentration (MIC) for Streptococcus mutans ATCC 25175. Antibacterial activity against a biofilm was evaluated in samples that were aged in artificial saliva for different times using spectral confocal laser microscopy and scanning electron microscopy. Kruskal-Wallis test using IBM SPSS Statistics version 23.0 software (SPSS Inc. ®, Chicago, IL, United States) were used, establishing the value of p <0.05 for statistical significance. The volume of the total biomass that formed in the samples aged for one day was significantly lower than the volume of the total biomass that was formed in those aged for additional days (p <0.001). Electron microscopy analysis revealed high porosity surfaces in all samples. Bacterial clusters wer e located next to large pores and irregular surfaces, while smooth surfaces had defined and linear organization cocci or simple chains. Considering the limitations of this study, the results suggest that the antibacterial activity of ZnO nanoparticles add ed to self-curing acrylic (ALIKE) is effective, mainly in fresh 1-day samples, independent of their concentration, and in samples with 16 MIC aged for 14 days, indicating it does not lose its antibacterial activity despite setting for more days. In addition, the ZnO nanoparticles added to ALIKE have the ability to inhibit the formation of biofilms, although they do not minimize the number of viable bacteria.

RESUMEN: El objetivo principal de este estudio fue investigar si nanopartículas de óxido de zinc (ZnO), incorporadas a acrílico acrilico de autocurado, tienen propiedades antimicrobianas contra Streptococcus mutans, uno de los microorganismos implicados en el desarrollo de caries. Se prepararon muestras de resina acrílica autopolimerizada mediante la incorporación de nanopartículas de ZnO a diferentes concentraciones basadas en la concentración mínima inhibitoria (MIC) para Streptococcus mutans ATCC 25175. Se evaluó la actividad antibacteriana contra una biopelícula en muestras envejecidas en saliva artificial para diferentes tiempos utilizando espectros microscopía láser confocal y microscopía electrónica de barrido. Se utilizó la prueba de Kruskal-Wallis utilizando el software IBM SPSS Statistics versión 23.0 (SPSS Inc. ®, Chicago, IL, Estados Unidos), estableciendo el valor de p <0,05 para la significancia estadística. El volumen de la biomasa total que se formó en las muestras envejecidas durante un día fue significativamente menor que el volumen de la biomasa total que se formó en las envejecidas durante días adicionales (p <0,001). El análisis de microscopía electrónica reveló superficies de alta porosidad en todas las muestras. Los cúmulos bacterianos se ubicaron junto a poros grandes y superficies irregulares, mientras que las superficies lisas tenían cocos o cadenas simples de organización lineal y definida. Considerando las limitaciones de este estudio, los resultados sugieren que la actividad antibacteriana de las nanopartículas de ZnO agregadas al acrílico autopolimerizable (ALIKE) es efectiva, principalmente en muestras frescas de 1 día, independientemente de su concentración, y en muestras con 16 MIC envejecidas para 14 días, lo que indica que no pierde su actividad antibacteriana a pesar de estar fraguada durante más días. Además, las nanopartículas de ZnO añadidas a ALIKE tienen la capacidad de inhibir la formación de biopelículas, aunque no minimizan el número de bacterias viables.

Phytochemicals with antifungal properties: Cure from nature

Aims@#The exploration of natural products with innovative uses is dynamic and expanding rapidly. Medicinal plants have fascinated many researchers that subsequently lead to research publications highlighting plant extracts with wide range of secondary metabolites such as flavonoids, alkaloids, glycosides, quinones, terpenoids, tannins and saponins that exhibit antimicrobial activities and disease control. The concentration of these bioactive compounds in each plant species varies based on the pathosystem and environmental conditions. This study aims to uncover the various types of phytochemicals with antifungal properties.@*Methodology and results@#Seven categories of plant-based antifungal compounds were reviewed, which are terpenoids, saponins, phenolic compounds, coumarins, alkaloids, essential oils and peptides, with examples and structures of some available compounds. The mechanism of action of each category of phytochemical was discussed. Also, the impact of some compounds was explained and elaborated. @*Conclusion, significance and impact of study@#It is of a great importance to explore natural plant fighters against fungal infection. Those active plant components do not only have antifungal properties, but they also help in the healing process and some even exhibit anticancer activities. The development and knowledge of antifungal activities from plant extracts have the potential for applications in antifungal therapy. Since the exact description of how antifungal compounds function in the human body is still unclear more studies are required to unveil phytochemicals’ properties and to elucidate their effects on living cells.

Antimicrobial susceptibility profile of historical and recent Brazilian pig isolates of Pasteurella multocida / Perfil de suscetibilidade a antimicrobianos de isolados históricos e contemporâneos de Pasteurella multocida de suínos no Brasil

Pasteurella (P.) multocida is the causative agent of pneumonic pasteurellosis in swine, which is commonly associated with the final stages of enzootic pneumonia or porcine respiratory disease complex. Although this syndrome is one of the most common and important diseases of pigs, data on antimicrobial susceptibility of P. multocida isolates are uncommon in Brazil. Therefore, the present study was carried out to determine and to compare antimicrobial susceptibility profile of Brazilian P. multocida isolated from pigs with lesions of pneumonia or pleuritis during two-time periods. Historical isolates (period of 1981 to 1997; n=44) and recent isolates (period of 2011 to 2012; n=50) were used to determine the MIC of amoxicillin, enrofloxacin, florfenicol and tetracycline by microbroth dilution. Florfenicol had the lowest level of resistance for both historical and recent isolates (0% and 6%, respectively), while tetracycline had the highest (20.5% and 34%, respectively). Multi-drug resistance (MDR) to amoxicillin/florfenicol/tetracycline was observed in 6% of recent isolates. There was a significant increase (p˂0.05) in resistance for amoxicillin and enrofloxacin in recent isolates compared with historic isolates (3.8% and 18%, respectively), most likely due to the selective pressure of antimicrobial usage to treat and prevent P. multocida infections. The results of this study showed an increase of isolates resistant to important drugs used in treatment of P. multocida infections in pigs, demonstrating the need for the implementation of rational use of antimicrobials in Brazilian swine industry.(AU)

Pasteurella (P.) multocida é o agente da pasteurelose pneumônica em suínos, a qual é comumente associada com o estágio final da pneumonia enzoótica suína ou complexo das doenças respiratórias dos suínos. Apesar de ser uma das doenças mais comuns e importantes na suinocultura, dados sobre suscetibilidade antimicrobiana de isolados de P. multocida são raros no Brasil. Dessa forma, o presente estudo foi realizado para determinar e comparar o perfil de suscetibilidade de isolados de P. multocida de suínos com lesões de pneumonia ou pleurite no Brasil durante dois períodos. Isolados históricos (período de 1981 a 1997; n=44) e contemporâneos (período de 2011 a 2012; n=50) foram usados para determinar a concentração inibitória mínima (CIM) de amoxicilina, enrofloxacina, florfenicol e tetraciclina através do teste de microdiluição em caldo. Florfenicol apresentou o menor nível de resistência para ambos os isolados históricos e contemporâneos (0% e 6%, respectivamente), enquanto que tetraciclina apresentou o maior nível de resistência (20.5% e 34%, respectivamente). Resistência a múltiplos antimicrobianos (amoxicilina, florfenicol e tetraciclina) foi observada em 6% dos isolados recentes. Foi observado aumento significativo (p˂0.05) na resistência a amoxicilina e enrofloxacina em isolados recentes comparado com isolados históricos (3.8% e 18%, respectivamente), provavelmente devido à pressão de seleção de antimicrobianos usados no tratamento e prevenção de infecções causadas por P. multocida. Os resultados deste trabalho demostraram o aumento de isolados resistentes a importantes drogas utilizadas no tratamento de infecções causadas por P. multocida em suínos, evidenciando a necessidade da implementação do uso racional de antimicrobianos na suinocultura brasileira.(AU)

Antimicrobial Activities of Daucus Carota Seeds on Selected Pathogenic Micro-organisms

Background: The antibacterial/antifungal toxicity of Daucus carota (carrot) seeds was evaluated using selected multi-drug resistant bacteria and yeast of clinical origin. Methods: The active constituents of the Daucus carota seeds were extracted using conventional Plant Tissue Homogenization method using cold distilled water, Ethanol and Methanol as solvents. Varying concentrations (5-250 mg/ml) of the three extracts were assayed for antimicrobial activity against the selected isolates- Salmonella typhi, Staphylococcus aureus, Escherichia coli, Klebseilla pneumoniae and Candida albicans; the agar well diffusion method was used. The antibiogram profile of the organisms was also obtained through disc diffusion method. Results: Similar activity was observed in the methanolic and ethanolic extracts while cold distilled water showed no activity on any of the isolates. The antibiotic susceptibility results showed that the isolates used are highly multi-drug resistant. Ofloxacin exhibited the most pronounced activity against all the isolates. Gentamicin and erythromycin both showed activity on Escherichia coli and Salmonella typhi. Lower concentrations of both extracts presented no inhibitory effects on the test organisms, thus resulting in high MIC values recorded for both extracts. Also, the extracts showed no bactericidal action against the isolates.  Conclusions: Observations from this research therefore affirm that Daucus carota seeds possess antimicrobial properties that may be explored as a source of future antimicrobial compounds.

In vitro evaluation of Schima wallichii (DC.)Korth.fruit for potential antibacterial activity.

Schima wallichii (DC.) Korth. is a large evergreen and well known tree of Sikkim Himalayan region. The bark of this plant is traditionally used as antipyretic, antiseptic, anthelmintic, wound healing agent. In the present study an attempt has taken to investigate for potential antibacterial activity by taking different extracts of fruits of Schima wallichii (DC.) Korth. against Gram-positive bacteria (Staphylococcus aureus NCTC 8530 and Bacillus liherfernis 10341) and Gram-negative bacteria (Escherichia coli HD10; Salmonella paratyphi A2 and Vibrio cholera 64). Antibacterial activity of Schima wallichii (DC.) Korth. fruit extracts (benzene, acetone and aqueous) were assayed by the disc diffusion method. Among all the extracts, acetone extract was found most active against Escherichia coli HD10 and Bacillus liherfernis 10341 but this extract have no effect in case of Vibrio cholera 64. The MIC (Minimum Inhibitory Concentrations) of the extract was found 100 μg/ml for Escherichia coli HD10 and 150 μg/ml for Bacillus liherfernis 10341. The study promises an interesting future for designing a potentially active antibacterial agent from Schima wallichii (DC.) Korth. fruit.

Avaliação da atividade antimicrobiana da planta Tradescantia pallida Munt (Taboquinha Roxa) / Evaluation of antimicrobial activity of the Tradescantia pallida Munt plant (Taboquinha Roxa)

RESUMO O objetivo deste estudo foi pesquisar o efeito antimicrobiano in vitro do extrato hidroalcóolico das folhas Tradescantia pallida Munt conhecida como Taboquinha roxa. Foram realizados testes em meio sólido, onde não observou qualquer halo de inibição, e o método de microdiluição, em que os resultados foram expressivos, com determinação da Concentração Inibitória Mínima (CIM) e Concentração Bactericida Mínima (CBM), com resultados em diferentes concentrações. Foram utilizadas cepas padrão de bactérias Gram positivas e Gram negativas. De acordo com os resultados, sugere-se que essa planta apresenta um potencial antimicrobiano.

ABSTRACT The aim of this study was to investigate the in vitro antimicrobial effect of the hydroalcoholic extract of the Tradescantia pallida Munt leaves,known as Taboquinha roxa. The tests were both conducted on solid mean, where it was not observed any zone of inhibition, and by the micro dilution method, in which the results of the Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) were significant and related with the different concentrations. Standard strains of bacteria type Gram positive and Gram negative were employed. According to the results, this plant has an antimicrobial potential.

Obtaining the essential oil of Syzygium aromaticum, identification of eugenol and its effect on Streptococcus mutans / Obtención del aceite esencial de Syzygium aromaticum, identificación del eugenol y su efecto sobre Streptococus mutans

Dental caries is a disease which affects the human oral cavity. Currently, the search for active principles of plants with antimicrobial effect seems promising for dental therapy. In this article the activity of the essential oil of Syzygium aromaticum (clove) was evaluated with an emphasis on its antimicrobial properties. The oil was obtained by hydrodistillation, characterized by thin layer chromatography and chemical tests. The main compound was identified in the oil obtained from the flower buds and its antibacterial activity against plank¬tonic cells Streptcoccus mutans ATCC700611 was assessed by performing serial dilutions, from 15 up to 1000 ug/mL, compared with 0.12 percent chlorhexidine and dimethylsulfoxide. MIC was also determined. Subsequently, UFC was analyzed and compared with CMR Test Ivoclar Vivadent. The efficiency in obtaining the oil was 2.20 percent. By using the CCD technique, a fraction was revealed by UV light, corresponding to eugenol. It had a good response for triterpenoids and flavonoids. It showed greater antimicrobial activity at concentrations of 1000, 500 and 250ug/ ml. The MIC and MBC of the oil was 125 to 250ug/mL, respectively. Eugenol was found as an active principle in the oil obtained. Currently, the impact of using plant extracts has favored the evaluation of alternative, effective and biocompatible antibacterial agents for the formulations of oral hygiene products applied to the prevention or treatment of oral diseases.

La caries dental es una enfermedad que afecta la cavidad oral en los humanos. Actualmente la búsqueda de principios activos de plantas con efecto antimicrobiano representa una promesa en la terapia Odontológica. El presente trabajo, evaluó la actividad, del aceite esencial de Syzygium aromaticum (clavo) con énfasis en su propiedad antimicrobiana. El aceite fue obtenido por hidrodestilación, caracterizado por cromatografía en capa delgada y pruebas químicas. Se iden¬tificó el compuesto principal en el aceite obtenido de los botones florales y se evaluó su actividad antibacteriana contra células plantónicas de Streptcoccus mutans ATCC (700611) realizándose diluciones seriadas; desde 15 hasta 1000ug/mL, comparándose con clorhexidina al 0.12 por ciento y dimetilsulfóxido, además se determinó la CMI. Posteriormente, se analizó las UFC, comparándose con el Test CMR® Ivoclar Vivadent. La eficiencia en la obtención del aceite fue de 2.20 por ciento. Por la técnica de CCD se identificó una fracción al revelado UV, corres¬pondiente al eugenol. Presentó respuesta positiva para flavonoides y triterpenos. Mostró mayor actividad antimicrobiana a las concentraciones de 1000, 500 y 250 ug/mL. La CMI y CMB del aceite, resultó a 125 y 250 ug/mL respectivamente. Se comprobó la presencia del eugenol como principio activo en el aceite obtenido. Actualmente la proyección del uso de extractos de plantas ha favorecido la evaluación de agentes antibacterianos alternos, eficaces y biocompatibles para su empleo en las formulaciones de productos de higiene bucal aplicados a la prevención o tratamiento de enfermedades orales.

Evaluation of anti-resistant activity of Auklandia(Saussurea lappa) root against some human pathogens

Objective:The antimicrobial activity of the ethanol extract of the Auklandia (Saussurea lappa) root plant was investigated to verify its medicinal use in the treatment of microbial infections. Methods:The antimicrobial activity of the ethanol extract was tested against clinical isolates of some multidrug-resistant bacteria using the agar well diffusion method. Commercial antibiotics were used as positive reference standards to determine the sensitivity of the clinical isolates. Results:The extracts showed significant inhibitory activity against clinical isolates of methicillin resistant Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, Extended Spectrum Beta-Lactemase, Acinetobacter baumannii. The minimum inhibitory concentration values obtained using the agar dilution test ranged from 2.0 μg/μL-12.0 μg/μL. In the contrary the water extract showed no activity at all against the tested isolates. Furthermore, the results obtained by examining anti-resistant activity of the plant ethanolic extract showed that at higher concentration of the plant extract (12 μg) all tested bacteria isolates were inhibited with variable inhibition zones similar to those obtained when we applied lower extract concentration using the well diffusion assay. Conclusion:The results demonstrated that the crude ethanolic extract of the Auklandia (Saussurea lappa) root plant has a wide spectrum of activity suggesting that it may be useful in the treatment of infections caused by the above clinical isolates (human pathogens).

Preliminary study on inhibitory effects of sub-MIC matrine alone or in combination with erythromycin On Staphylococcus epidermidis biofilm / 中华微生物学和免疫学杂志

Objective To observe the inhibitory effects of sub-MIC matrine alone and in combination with erythromycin on Staphylococcus epidermidis biofilms and their influences on morphological changes of the biofilms.Methods Minimum inhibitory concentrations (MIC) of matrine and erythromycin against Staphylococcus epidermidis were determined by the serial dilution method,antibacterial activity of matrine combined with erythromycin against planktonic S.epidermidis was evaluated by the checkerboard method.S.epidermidis biofilms were constructed in vitro,XTT reduction assay was used to evaluate influences of sub-MIC matrine alone and in combination with erythromycin on metabolism and adhesion of S.epidermidis biofilms,and scanning electronic microscope(SEM) was applied to observe the morphological and the structural changes of the biofilms.Results The MIC of erythromycin to S.epidermidis was 7.8125 μg/ml,while the MIC of matrine was greater than 1000 μg/ml,besides,a synergistic effect between erythronmycin and matrine on planktonic S.epidermidis was shown (FIC＜0.5).The sub-MIC matrine had no significant inhibitory effect on adhesion of S.epidermidis,and also the combination of the two agents was better than was used alone.However,the sub-MIC matrine had inhibitory effects on metabolism and morphology of S.epidermidis biofilms,and the combination of the two agents was weaker than was used alone.Conclusion Both the sub-MIC matrine and erythromycin had a significant inhibitory effect on S.epidermidis biofilm formation.Combination of the two agents showed synergistic effects on plankton and adhesion of S.epidermidis,but showed no synergistic effect on metabolism and morphology of the biofilms.

Screening antimicrobial activity of various extracts of Urtica dioica

Urtica dioica or stinging nettle is traditionally used as an herbal medicine in Western Asia. The current study represents the investigation of antimicrobial activity of U. dioica from nine crude extracts that were prepared using different organic solvents, obtained from two extraction methods: the Soxhlet extractor (Method I), which included the use of four solvents with ethyl acetate and hexane, or the sequential partitions (Method II) with a five solvent system (butanol). The antibacterial and antifungal activities of crude extracts were tested against 28 bacteria, three yeast strains and seven fungal isolates by the disc diffusion and broth dilution methods. Amoxicillin was used as positive control for bacteria strains, vancomycin for Streptococcus sp., miconazole nitrate (30µg/mL) as positive control for fungi and yeast, and pure methanol (v/v) as negative control. The disc diffusion assay was used to determine the sensitivity of the samples, whilst the broth dilution method was used for the determination of the minimal inhibition concentration (MIC). The ethyl acetate and hexane extract from extraction method I (EA I and HE I) exhibited highest inhibition against some pathogenic bacteria such as Bacillus cereus, MRSA and Vibrio parahaemolyticus. A selection of extracts that showed some activity was further tested for the MIC and minimal bactericidal concentrations (MBC). MIC values of Bacillus subtilis and Methicillin-resistant Staphylococcus aureus (MRSA) using butanol extract of extraction method II (BE II) were 8.33 and 16.33mg/mL, respectively; while the MIC value using ethyl acetate extract of extraction method II (EAE II) for Vibrio parahaemolyticus was 0.13mg/mL. Our study showed that 47.06% of extracts inhibited Gram-negative (8 out of 17), and 63.63% of extracts also inhibited Gram-positive bacteria (7 out of 11); besides, statistically the frequency of antimicrobial activity was 13.45% (35 out of 342) which in this among 21.71% belongs to antimicrobial activity extracts from extraction method I (33 out of 152 of crude extracts) and 6.82% from extraction method II (13 out of 190 of crude extracts). However, crude extracts from method I exhibited better antimicrobial activity against the Gram-positive bacteria than the Gram-negative bacteria. The positive results on medicinal plants screening for antibacterial activity constitutes primary information for further phytochemical and pharmacological studies. Therefore, the extracts could be suitable as antimicrobial agents in pharmaceutical and food industry.

Urtica dioica u ortiga se utiliza tradicionalmente como medicina herbaria en el oeste de Asia. En esta investigación se estudia la actividad antimicrobiana de nueve extractos crudos de U. dioica, los cuales fueron preparados utilizando diferentes disolventes orgánicos y obtenidos a partir de dos métodos de extracción: el extractor Soxhlet (Método I), que incluía el uso de cuatro disolventes con acetato de etilo y hexano, y las particiones secuenciales (Método II) con un sistema de cinco disolventes (butanol). Las actividades antibacterianas y antifúngicas de extractos crudos fueron ensayados contra 28 bacterias, tres cepas de levadura y siete cepas fúngicas por la difusión en disco y el método de dilución en caldo. La amoxicilina se utilizó como control positivo para cepas de bacterias, vancomicina para Streptococcus sp., nitrato de miconazol (30μg/mL) como control positivo para los hongos y levaduras, y el metanol puro (v / v) como control negativo. El ensayo de difusión en disco se utilizó para determinar la sensibilidad de las muestras, mientras que el método de dilución en caldo se utilizó para la determinación de la concentración de inhibición mínima (CIM). El acetato de etilo y el extracto de hexano del método de extracción I (AE I y EH I) mostraron mayor inhibición contra algunas bacterias patógenas tales como Bacillus cereus, MRSA y Vibrio parahaemolyticus. Una selección de extractos que mostraron algún tipo de actividad se probó para el CIM y las concentraciones mínimas bactericidas (CMB). Los valores de CIM de Bacillus subtilis y de Staphylococcus aureus resistentes a la meticilina (MRSA) usando extracto de butanol mediante el método de extracción II (EB II) fueron: 8.33 y 16.33mg/ mL, respectivamente; mientras que el valor de MIC con el uso del extracto de acetato de etilo por el Método de extracción II (EAE II) para Vibrio parahaemolyticus fue 0.13mg/mL. Nuestro estudio mostró que el 47.06% de los extractos inhibieron bacterias Gram-negativas (8 de 17), y el 63,63% de los extractos también inhibieron bacterias Gram-positivas (7 de 11), además que estadísticamente la frecuencia de la actividad antimicrobiana fue de 13.45% (35 de 342), que de este porcentaje un 21.71% pertenece alos extractos de actividad antimicrobiana con el método de extracción I (33 de 152 de los extractos crudos) y un 6.82% del método de extracción II (13 de 190 de los extractos crudos). Sin embargo, los extractos crudos del método I exhibieron una mejor actividad antimicrobiana contra las bacterias Gram-positivas que las Gram-negativas. Los resultados positivos en la detección de plantas medicinales para la actividad antibacteriana constituye información primaria para la realización de nuevos estudios fitoquímicos y farmacológicos. Por lo tanto, los extractos podrían ser adecuados como agentes antimicrobianos en la industria farmacéutica y de alimentos.

Evaluation of Malawian Vernonia glabra (Steetz)Vatke leaf and Securidaca longepedunculata (Fresen) root extracts for antimicrobial activities.

The aqueous, ethanol and acetone crude extracts and dichloromethane, hexane, ethyl acetate and nbutanol fractions of the Securidaca longepedunculata roots and Vernonia glabra leaves were studied for their antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans using agar well diffusion method. The phytochemical presents, as well as the minimum inhibitory concentration (MIC) and minimum bacteriacidal/fungicidal concentration (MBC/MFC) of the extracts were also determined using standard methods. Results obtained indicated that Vernonia glabra leaves acetone extracts had excellent antimicrobial activity against E. coli, P. aeruginosa and ethanol extracts against S. aureus. The n-butanol fractions had the best activity against E. coli and S. aureus, dichloromethane fraction against P. aeruginosa and ethyl acetate fraction against C. albicans. For S. longepedunculate root ethanol extracts showed best activity against E. coli, acetone extract against P. aeruginosa and aqueous extract against C. albicans. The n-butanol fractions had best activity against E. coli, P. aeruginosa and C. albicans. These results verified the claims by traditional healers in Malawi that the plants extracts treats bacteria related ailments such as diarrhoea and could be a potential source for development of phytomedicine.

An analysis on 200 randomized clinical isolates of Mycobacterium in Sichuan / 中华微生物学和免疫学杂志

Objective To find out the resistant situation and drug of Mycobacteria patients in Sichuan and offer foundation for clinical.Methods Two hundred randomized clinical isolates of Mycobacterium were determined by Roche drug sensitivity and minimum inhibitory concentration (MIC) method.Results Of the 200 clinical isolates,192 stains were Mycobacterium tuberculosis(MTB) (96.0％),8 strains (4.0％) were non-tuberculosis mycobacterium(NTM).Of the 192 MTB strains,108( 57.3％ ) sensitive strains and 84 (43.7％)stains were resistant to one or more than one drugs.Among these 84 resistant strains 23 were multi-drug resistant ( MDR,12.0％ ),4 were extensively drug resistant( XDR,2.1％ ).The anti-TB drug resistance rates were:SM(16.7％),INH(20.8％),RFP(17.2％),EMB(10.9％),PI(16.1％),LFX(8.8％),AMK ( 16.7％ ),CPM ( 6.2％ ),PTA ( 33.3％ ),respectively.Conclusion The resistance rate of tuberculosis keeps at a high level in Sichuan,especially the resistance rate of multiple (≥4) drug,we should oar attention.

Biological and physicochemical stability of ceftazidime and aminophylline on glucose parenteral solution

Ceftazidime is a broad spectrum antibiotic administered mainly by the parenteral route, and it is especially effective against Pseudomonas aeruginosa. The period of time in which serum levels exceed the Minimum Inhibitory Concentration (MIC) is an important pharmacodynamic parameter for its efficacy. One of the forms to extend this period is to administer the antibiotic by continuous infusion, after prior dilution in a Parenteral Solution (PS). The present work assessed the stability of ceftazidime in 5% glucose PS for 24 hours, combined or not with aminophylline, through High Performance Liquid Chromatography (HPLC). The physicochemical evaluation was accompanied by in vitro antimicrobial activity compared MIC test in the 24-hour period. Escherichia coli and Pseudomonas aeruginosa were the microorganisms chosen for the MIC comparison. The HPLC analysis confirmed ceftazidime and aminophylline individual stability on PS, while the MIC values were slightly higher than the mean described in the literature. When both drugs were associated in the same PS, the ceftazidime concentration by HPLC decreased 25% after 24 hours. Not only did the MIC values show high loss of antibiotic activity within the same period, but also altered MIC values immediately after the preparation, which was not detected by HPLC. Our results indicate that this drug combination is not compatible, even if used right away, and that PS might not be the best vehicle for ceftazidime, emphasizing the importance of the MIC evaluation for drug interactions.

Ceftazidima é um antimicrobiano administrado por via parenteral, que apresenta amplo espectro de ação, principalmente contra Pseudomonas aeruginosa. O tempo em que a concentração sérica de ceftazidima permanece acima da concentração mínima inibitória (MIC) é um importante parâmetro farmacodinâmico para a determinação da eficácia antimicrobiana e pode ser potencializado através da utilização de infusão contínua em soluções parenterais (PS). Este artigo visa a avaliar a estabilidade da ceftazidima em solução de glicose 5%, na presença e na ausência do fármaco aminofilina, através de cromatografia líquida de alta eficiência HPLC e MIC durante o período de 24 horas. Os microorganismos selecionados para a determinação do MIC foram Escherichia coli e Pseudomonas aeruginosa. Os ensaios em cromatógrafo líquido confirmaram a estabilidade dos fármacos ceftazidima e aminofilina quando são individualmente associados em PS, enquanto os valores de MIC ficaram maiores que os valores encontrados na literatura. Quando ambos os fármacos foram associados na mesma solução parenteral a concentração de ceftazidima obtida por HPLC diminuiu 25% depois de 24 horas. Os valores de MIC mostraram maior decaimento da atividade antimicrobiana neste mesmo período e também valores de MIC alterados nas soluções preparadas no tempo zero, decaimento este que não foi detectado em HPLC. Os resultados indicaram incompatibilidade na associação dos fármacos em PS, enfatizando a importância dos resultados de MIC para interações de fármacos.

Antimicrobial activities of the rhizome extract of Zingiber zerumbet Linn

Objective: To investigate antimicrobial effects of ethanolic extract of Zingiber zerumbet (Z. zerumbet) (L.) Smith and its chloroform and petroleum ether soluble fractions against pathogenic bacteria and fungi. Methods: The fresh rhizomes of Zingiber zerumbet were extracted in cold with ethanol (4.0 L) after concentration. The crude ethanol extract was fractionated by petroleum ether and chloroform to form a suspension of ethanol extract (15.0 g), petroleum ether fraction (6.6 g) and chloroform soluble fraction (5.0 g). The crude ethanol extract and its petroleum ether and chloroform fractions were evaluated for antibacterial and antifungal activity against thirteen pathogenic bacteria and three fungi by the disc diffusion method. Commercially available kanamycin (30 μg/disc) was used as standard disc and blank discs impregnated with the respective solvents were used as negative control. Results: At a concentration of 400 μg/disc, all the samples showed mild to moderate antibacterial and antifungal activity and produced the zone of inhibition ranging from 6 mm to 10 mm. Among the tested samples, the crude ethanol extract showed the highest activity against Vibrio parahemolyticus (V. parahemolyticus). The minimum inhibitory concentration (MIC) of the crude ethanol extract and its fractions were within the value of 128-256 μg/mL against two Gram positive and four Gram negative bacteria and all the samples showed the lowest MIC value against V. parahemolyticus (128 μg/mL). Conclusions: It can be concluded that, potent antibacterial and antifungal phytochemicals are present in ethanol extract of Z. zerumbet (L).

Antimicrobial efficacy of fruit extracts of two piper species against selected bacterial and oral fungal pathogens

Aim: To assess the antimicrobial efficacy of five solvent extracts of two Piper species commonly used in diet and traditional medicine, P. cubeba and P. longum, against selected bacterial and oral fungal pathogens i.e. Streptococcus mutans, Staphylococcus aureus, Candida albicans and Saccharomyces cerevisiae. Methods: The antimicrobial activity of five extracts of cubeb berries and Indian long pepper fruits was determined by the agar well diffusion method. The minimum inhibitory concentration (MIC) for the acetonic, methanolic and ethanolic extracts was determined by the modified agar well diffusion method. Results: Of the 5 fruit extracts evaluated, acetone, ethanol and methanol extracts of both the Piper spp. were found to have variable antimicrobial activities against all the four oral pathogens. The acetonic fruit extract of P. cubeba was the most effective against both the yeasts with the highest zone of inhibition (15.31 mm) against C. albicans followed by the methanolic (12.31 mm) and ethanolic (11.94 mm) extracts. C. albicans was found to be most sensitive pathogen, which survived up to 6.25 mg/mL in the acetonic extract (MIC = 12.5 mg/mL) followed by the methanolic and ethanolic extracts (MIC = 25 mg/mL). The acetonic, methanolic and ethanolic extracts of P. longum fruits showed almost equal inhibition zones of both yeasts, ranging between 10.64 and 14 mm. C. albicans survived up to 12.5 mg/mL (MIC= 25 mg/mL) while S.cerevisiae survived up to 25 mg/mL (MIC = 50 mg/mL). Conclusions: The crude extracts obtained from the fruits of the two Piper spp. may be used to treat oral fungal species, especially C. albicans, as they produced larger inhibition zones than antifungal drugs often used to treat these pathogens.

Fungal Profile and Susceptibility Pattern in Cases of Keratomycosis

The present study was undertaken to find out various fungi causing keratomycosis and to determine the antifungal susceptibility profile of these isolates. One hundred corneal scrapings from patients with corneal ulcers were subjected to KOH wet mount preparation. Thirty samples which were positive for fungal elements on direct microscopic examination were cultured on Sabouraud's dextrose agar medium(SDA).The isolates were identified and were subjected to drug susceptibility tests for ketoconazole and fluconazole by tube dilution method. Incidence of fungal corneal ulcers was maximum in the age group of 20-49 years (56.67%). Agriculturists constituted the largest group (53.33%), history of trauma was present in 90% of the patients. Aspergillus species were the commonest isolates (70%) followed by candida (20%), alternaria (6.70%) and penicillium (3.30%). MIC of ketoconazole varied from 0.5mg/ml to 10 mg/ml. MIC of fluconazole varied from 0.5 - 10 mg/ml and 19 isolates of fungi did not show any sensitivity to fluconazole upto concentration of 10 mg/ml which was the upper limit of the test system. As agricultural activity and related ocular trauma were principal causes of mycotic keratitis, KOH wet mount preparation is an essential tool in the diagnosis of these infections. It is a very simple and sensitive method. Susceptibility pattern to antifungal drugs was determined to optimize therapeutic response in eye infections.

Antimicrobial resistance of bacteria strains producing extend spectrum β-lactamase in clinic / 中国康复理论与实践

@#ObjectiveTo investigate the resistance character and trend of bacteria strains producing extend spectrum β-lactamase (ESBLs) in clinic.MethodsThe ESBLs-producting K. pneumoniae and E.coli producing ESBLs isolated from Apr 2001 to Mar 2004 in our hospital were screened and confirmed according to NCCLs method.ResultsK. pneumoniae and E.coli with the ESBLs phenotype were increased in recent 3 years with the resistance rate and Gm(MIC) also higher than that not producing ESBLs.ConclusionThe dection of bacteria strains producing ESBLs will be enhanced in order to provide reasonable treatment information.

Analyses on drug resistance phenotype of multi-drug resistant Pseudomonas aeruginosa and on antibacterial activity of combined antimicrobial agents / 解放军医学杂志

Objctive To investigate the zymogenic state and drug resistance of multi-drug resistant Pseudomonas aeruginosa (MDRP) for providing a laboratory basis of combined use of drugs against MDRP in clinical practice. Methods All isolates were isolated by routine procedures and identified by VITEK-2 automatic bacterial identification instrument. Following the CLSI instruction, doubling dilution in agar plates was performed for MIC detection. Results MDRP were 22.77% ( 86.96% for sputum) from 101 strains Pseudomonas aeruginosa, which were isolated from clinical specimens. Positive rates of MDRP producing metallo-?-lactmases were 91.3%, positive rates for producing induced Ampc and plasmid Ampc ?-lactamase were 52.17% and 21.74%, respectively. The ratio between Meropenem and Imipenem higher then 1 was 34.78%. The bacterial inhibitory rates of Polymyxin B and Imipenem were zero, that of Amikaein and Ceftaxidime were 4.35%, that of Ciprofloxacin and Cefoperazone/sulbactam were 43.48%, that of Pazufioxacin and Piperacillin/Tazobactam were 21.74% and 26.07%, and that of Meropenem was 47.83%. The combined use of Cefoperazone/sulbactam, Cefpirome, Piperacillin/Tazobactam with Amikacin resulted in bacteriostatic rate of 65.2%, 47.8%, 43.5%, respectively. Conclusoins MDRP is main micro-organism found in respiratory tract specimens. Drug resistance of MDRP is related to multiple drug-resistant mechanisms. Clinicians should first select enzyme inhibitory-drug (Cefoperazone/sulbactam or Piperacillin/Tazohaetam) with Amikacin or Polymyxin B to treat clinical MORP infection, and re-adjust the type of antibiotics rationally according to patients' symptoms, phenotype of the drug-resistant pathogen, the results of drug susceptibility test, and the effect on the patients.

IN VITRO ANTIBACTERIAL ACTIVITIES OF FOUR ANTIBACTERIAL AGENTS TO NEISSERIA GONORRHEAE / 重庆医科大学学报

In vitro susceptibilities of 38 strains of gonococcus to 4 antibacterial agents wers tested by the agar double dilution method.Beta-lactamase of the bacteria was also tested.The rusults showed that in 38 strains of gonococcus 21.1% were penicillin resistant, 7.9% were PPNG strains, 7.9%were spectinomycin resistant,all of them were susceptible to both ofloxalin and norfloxacin.The MIC50 and MIC90 of ofloxacin and norfloxacin were very low.It was indicated thaat much attention should be paid to the resistance of gorcccccus to penicillin and spectinomycin. Ofloxacin and norfloxacin should be recommended in treatment of gonorrhea