Antimicrobial drug resistance of Staphylococcus aureus in dairy products.

OBJECTIVE: To evaluate the prevalence of multidrug resistant Staphylococcus aureus (S. aureus) in dairy products. METHODS: Isolation and identification of S. aureus were performed in 3 dairy-based food products. The isolates were tested for their susceptibility to 5 different common antimicrobial drugs. RESULTS: Of 50 samples examined, 5 (10%) were contaminated with S. aureus. Subsequently, the 5 isolates were subjected to antimicrobial resistance pattern using five antibiotic discs (methicillin, vancomycin, kanamycin, chloramphenicol and tetracycline). Sample 29 showed resistance to methicillin and vancomycin. Sample 18 showed intermediate response to tetracycline. The other samples were susceptible to all the antibiotics tested. CONCLUSIONS: The results provide preliminary data on sources of food contamination which may act as vehicles for the transmission of antimicrobial-resistant Staphylococcus. Therefore, it enables us to develop preventive strategies to avoid the emergence of new strains of resistant S. aureus.

Extraction, isolation and characterization of bioactive compounds from plants' extracts.

Natural products from medicinal plants, either as pure compounds or as standardized extracts, provide unlimited opportunities for new drug leads because of the unmatched availability of chemical diversity. Due to an increasing demand for chemical diversity in screening programs, seeking therapeutic drugs from natural products, interest particularly in edible plants has grown throughout the world. Botanicals and herbal preparations for medicinal usage contain various types of bioactive compounds. The focus of this paper is on the analytical methodologies, which include the extraction, isolation and characterization of active ingredients in botanicals and herbal preparations. The common problems and key challenges in the extraction, isolation and characterization of active ingredients in botanicals and herbal preparations are discussed. As extraction is the most important step in the analysis of constituents present in botanicals and herbal preparations, the strengths and weaknesses of different extraction techniques are discussed. The analysis of bioactive compounds present in the plant extracts involving the applications of common phytochemical screening assays, chromatographic techniques such as HPLC and, TLC as well as non-chromatographic techniques such as immunoassay and Fourier Transform Infra Red (FTIR) are discussed.

Antimicrobial Activity of Emilia sonchifolia DC., Tridax procumbens L. and Vernonia cinerea L. of Asteracea Family: Potential as Food Preservatives.

Chemical preservatives have been used in the food industry for many years. However, with increased health concerns, consumers prefer additive-free products or food preservatives based on natural products. This study evaluated antimicrobial activities of extracts from Emilia sonchifolia L. (Common name: lilac tassel flower), Tridax procumbens L. (Common name: tridax daisy) and Vernonia cinerea L. (Common name: Sahadevi), belonging to the Asteracea family, to explore their potential for use against general food spoilage and human pathogens so that new food preservatives may be developed. Three methanol extracts of these plants were tested in vitro against 20 bacterial species, 3 yeast species, and 12 filamentous fungi by the agar diffusion and broth dilution methods. The V. cinerea extract was found to be most effective against all of the tested organisms and the methanol fraction showed the most significant (p < 0.05) antimicrobial activity among all the soluble fractions tested. The minimum inhibitory concentrations (MICs) of extracts determined by the broth dilution method ranged from 1.56 to 100.00mg/mL. The MIC of methanol fraction was the lowest in comparison to the other four extracts. The study findings indicate that bioactive natural products from these plants may be isolated for further testing as leads in the development of new pharmaceuticals in food preservation as well as natural plant-based medicine.

Antimicrobial Activity of Emilia sonchifolia DC., Tridax procumbens L. and Vernonia cinerea L. of Asteracea Family: Potential as Food Preservatives

Chemical preservatives have been used in the food industry for many years. However, with increased health concerns, consumers prefer additive-free products or food preservatives based on natural products. This study evaluated antimicrobial activities of extracts from Emilia sonchifolia L. (Common name: lilac tassel flower), Tridax procumbens L. (Common name: tridax daisy) and Vernonia cinerea L. (Common name: Sahadevi), belonging to the Asteracea family, to explore their potential for use against general food spoilage and human pathogens so that new food preservatives may be developed. Three methanol extracts of these plants were tested in vitro against 20 bacterial species, 3 yeast species, and 12 filamentous fungi by the agar diffusion and broth dilution methods. The V. cinerea extract was found to be most effective against all of the tested organisms and the methanol fraction showed the most significant (p < 0.05) antimicrobial activity among all the soluble fractions tested. The minimum inhibitory concentrations (MICs) of extracts determined by the broth dilution method ranged from 1.56 to 100.00mg/mL. The MIC of methanol fraction was the lowest in comparison to the other four extracts. The study findings indicate that bioactive natural products from these plants may be isolated for further testing as leads in the development of new pharmaceuticals in food preservation as well as natural plant-based medicine.

Antimicrobial activities of Psophocarpus tetragonolobus (L.) DC extracts.

Consecutive chloroform, ethanol, and ethyl acetate partitions of extracts from winged bean [Psophocarpus tetragonolobus (L.) DC] root, stem, leaf, and pod extracts were tested for their antimicrobial activity against 19 microbial species, including 11 bacterial pathogens, four yeasts, and four molds using the disk diffusion assay technique. The pod extract was found to be most effective against all of the tested organisms, followed by the stem, root, and leaf extracts, and the ethanol fraction showed the most significant (p < 0.05) antimicrobial activity against all of the tests among three soluble fractions of extract, followed by the ethyl acetate and chloroform fractions. The minimum inhibitory concentrations (MICs) of extracts determined by the broth dilution method ranged from 1.25 to 10.0 mg/mL. The MIC of ethanol fraction of pod extracts was the lowest by comparison with the other two extracts. The MIC for fungi was at or below 2.5 mg/mL and for bacteria was at or above 2.5 mg/mL.