BACTERIOLOGIE MEDICALE TECHNIQUES USUELLES PDF

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This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Pteleopsis hylodendron Combretaceae is used in Cameroon and West Africa folk medicine for the treatment of various microbial infections measles, chickenpox, and sexually transmitted diseases.

The antibacterial properties of the methanolic extract and fractions from stem bark of Pteleopsis hylodendron were tested against three Gram-positive bacteria and eight Gram-negative bacteria using Agar-well diffusion and Broth microdilution methods.

In addition, the crude extract and some fractions showed good antioxidant potential with inhibition values ranging from These results provide promising baseline information medicwle the potential use of this plant as well as some of the fractions in the treatment of infectious diseases and oxidative stress. Since the successive introduction of various antibiotics into therapeutics, the sensitivity of pathogenic microorganisms changed a lot so that the proportion of antibiotically resistant strains is currently important tedhniques 1 ], what involves an increase in seriousness of infectious diseases as gastroenteritis GE which are a problem of public health on a worldwide scale but especially in Africa [ 2 ].

Diarrhea, its main characteristic is a major cause of morbidity and mortality among children in developing countries. Moreover, therapy with synthetic antibiotics is not always possible because of their high cost as well as toxicity due to their extended use. To overcome this problem, people in developing countries use preparations obtained from plants following folk tradition for their primary health care because of low cost with little or no undesirable side effects [ 4 ].

The plants represent a potential and almost inexhaustible source of new anti-infective compounds [ 5 ] and many of them are used to treat GE effectively [ 6 ]. The genus Pteleopsis is represented in Africa by ten species but only P. The aqueous decoction of the stem bark of P. Phytochemical, antimicrobial, toxicity and antioxidant works have been previously reported of this plant [ 910 ].

In the same logic, we have analysed the stem bark of Pteleopsis hylodendron and report here the antibacterial activity on pathogenic bacteria of the gastro-intestinal tract and antioxidant activity of the crude extract and fractions. The stem bark of P. Five bacterial strains and six isolates known to be pathogenic of the gastro-intestinal tract were used in this work.

The bacterial cell suspension was prepared at 1. The air-dried and powdered stem bark of Pteleopsis hylodendron 2. Results were evaluated by measuring the inhibition zones around each well.

Bactériologie médicale, techniques usuelles + Agenda – EM|consulte

The assay was done in triplicate and the mean diameters recorded as inhibition zones. A two-fold serial dilution of the crude extract MIC values are recorded as the lowest concentration of the substance that completely inhibited bacterial growth that is, the solution in the well remained clear after incubation with INT.

MBCs were defined as the lowest concentration yielding negative subcultures. The experiments were performed in triplicate. Amoxicillin, ciprofloxacin and gentamicin at the concentration ranging between and 0. The free radical scavenging activity of the extract and fractions on the stable radical DPPH were estimated by usyelles method of Mensor et al.

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L-Ascorbic acid was used as positive control. The percentage of DPPH radical scavenging activity was calculated using the following formula: In bavteriologie assay antioxidant capacity is determined by measuring the inhibition of the volatile organic compounds and the meedicale diene hydroperoxides arising from linoleic acid oxidation [ 16 ].

Chloroform was completely evaporated using a vacuum evaporator. Same procedure was repeated with L-Ascorbic acid used as a standard control and a blank. Antioxidative capacity of the extract was compared with those of ascorbic acid and blank. Chemical tests were carried out on the methanolic extract and fractions using standard procedures to identify the constituents alkaloids, anthocyanins, anthraquinones, coumarins, flavonoids, glycosides, phenols, polyphenols, saponins, tannins, triterpenes, and sterols as described by Brunetton [ 17 ].

Phytochemical screening revealed the presence of medicinally active constituents. The differences in the composition between crude extract and fractions and between fractions were noted. Except F Aall other substances contained at least one chemical group.

Alkaloids, anthocyanins, anthraquinones, flavonoids, glycosides, phenols, polyphenols, saponins, and tannins were present in crude extract while coumarins, sterols, and triterpenes were absent. It is the same for F G and F H alkaloids, anthocyanins, anthraquinones, flavonoids, bqcteriologie, polyphenols, and tannins ; F I and F J flavonoids, glycosides, phenols, polyphenols, saponins, and tannins.

The results of the antibacterial activity by the Agar-well diffusion method are presented in Table 1. At the three concentrations of the methanolic extract tested, ID ranged from 0.

Chemotherapy Research and Practice

No activity was recorded at 2. In view of the results obtained by diffusion method, MIC and MBC values of the crude extract and fractions were established and the results are shown in Tables 2 and 3.

The important activity on S. On the contrary, F E and F F saw their activity increasing significantly. Indeed, on five of the eleven bacteria E. According to Marmonier [ 18 ], plant extract and fractions exerted two types of activities: Methanolic extract and fractions of P. The results are presented in Tables 4 and 5. Activity increased in a concentration-dependant manner compared to L-ascorbic acid positive antioxidant control.

Phytochemical screening of the methanolic extract and fractions of P. Other investigators [ 1920 ] have reported the presence of these components in the Combretaceae family to which belongs the studied plant. However, Ngounou et al. This difference can be attributed to the difference in the geographical region, soil composition, and age of the plant [ 17 ].

The antimicrobial activities of Pteleopsis species were reported [ 1923 ]. Generally, the methanolic extract and some fractions of the stem bark of P. These broad spectra of action could be related to their chemical components [ 24 ]. Among these compounds, tannins induce an important antimicrobial activity because they have an ability to inactivate microbial adhesions, enzymes, cell envelope transport proteins, and so forth, [ 25 ].

Due to their ability to bind to proteins and metals, tannins also inhibit the growth of microorganisms through substrate and metal ion deprivation [ 26 ].

However, differences in chemical composition recorded between the crude extract and some fractions may explain their different degree of antimicrobial properties.

Also, the amount of the active components in the crude extract may be diluted and fractionation may have increased their concentrations, thus the activities in the fractions [ 27 ].

MIC values obtained from the extract by micro-dilution method revealed that S. It was reported [ 29 ] that S. This may suggest that the mode of action of the extract was not related to the cell wall composition. This may suggest that this microbe required high concentrations of the substance tested and synergic effect of chemical compounds as extract.

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This may suggest these compounds which also present in the methanolic extract do not have a detectable antibacterial activity. However, alkaloids were reported to possess antibacterial activities [ 30 ]. Differences in activity between these fractions could be related to the absence of anthocyanins in F F and anthraquinones in F E. Generally, it is difficult at the sight of results of the phytochemical screening to attribute the activities recorded to a chemical compounds group.

As L-ascorbic acid, the methanolic extract and some fractions showed great antioxidant potentials. This particularly high activity could be attributed to the presence of phenolic compounds [ 31 ]. The antioxidant activity of phenolic compounds is mainly due to their redox properties, which can play an important role in neutralizing free radicals, quenching singlet and triplet oxygen species, or decomposing peroxides [ 32 ]. Numerous studies have suggested flavonoids, anthraquinones, anthocyanins and tannins [ 3334 ] for antioxidant activity.

Previous phytochemical investigations on this plant have reported the presence of ellagic acid derivatives as antioxidant source [ 22 ]. These results provide promising baseline information for the potential use of this plant as well as some of the fractions in the treatment of GE and oxidative stress. F E and F F by their high antibacterial activity could be the base of development of new antibacterial agents with broad spectra.

Their purification and pharmacological and toxicity studies are essential. Chemotherapy Research and Practice. Abstract Pteleopsis hylodendron Combretaceae is used in Cameroon and West Africa folk medicine for the treatment of various microbial infections measles, chickenpox, and sexually transmitted diseases.

Introduction Since the successive introduction of various antibiotics into therapeutics, the sensitivity of pathogenic microorganisms changed a lot so that the proportion of antibiotically resistant strains is currently important [ 1 ], what involves an increase in seriousness of infectious diseases as gastroenteritis GE which are a problem of public health on a worldwide scale but especially in Africa [ 2 ].

Material and Methods 2. Plant Material The stem bark of P. Microorganisms Five bacterial strains and six isolates known to be pathogenic of the gastro-intestinal tract were used in this work. Extraction and Fractionation The air-dried and powdered stem bark of Pteleopsis hylodendron 2. Phytochemical Screening Chemical tests were carried out on the methanolic extract and fractions using standard procedures to identify the constituents alkaloids, anthocyanins, anthraquinones, coumarins, flavonoids, glycosides, phenols, polyphenols, saponins, tannins, triterpenes, and sterols as described by Brunetton [ 17 ].

Phytochemical Screening Phytochemical screening revealed the presence of medicinally active constituents. Antibacterial Activity The results of the antibacterial activity by the Agar-well diffusion method are presented in Table 1.

ID mm of the methanolic extract of P. Antioxidant potential of the crude extract and fractions of P. Antioxidant potential of the crude extract of P. View at Google Scholar J. View at Google Scholar E. View at Google Scholar B. View at Google Scholar C. View at Google Scholar H. De Groot, and L. View at Google Scholar F. View at Google Scholar G.

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