Microbiological Testing of Probiotic Preparations.

Probiotic microorganisms that are potentially beneficial to the health of the host are commercially available in a great variety of products. Not all microorganism strains present in products have proven beneficial to the health properties. These products include not only foodstuffs but also dietary supplements, food for special medical purposes, medicinal products, as well as cosmetics and medical devices. These products contain from one to a dozen bacterial strains of the same or different species and sometimes also fungal strains. Since the pro-health effects of probiotics depend on a specific strain, the number of its cells in a dose, and the lack of pathogenic microorganisms, it is extremely important to control the quality of probiotics. Depending on the classification of a given product, its form, and its content of microorganisms, the correct determination of the number of microorganisms and their identification is crucial. This article describes the culture-dependent and culture-independent methods for testing the contents of probiotic microorganisms, in addition to biochemical and genetic methods of identification. The microbiological purity requirements for various product categories are also presented. Due to numerous reports on the low quality of probiotic products available on the market, it is important to standardise research methods for this group of products and to increase the frequency of inspections of these products.

Are Probiotic Really Safe for Humans?

Probiotic bacteria have been used as a health-promoting factor for a very long time. Nowadays, products containing probiotic bacteria are becoming more and more popular on the market. The term probiotics refers to the products belonging to the following groups: probiotic drugs (medicinal products - live biotherapeutic products for human use), medical devices, probiotic foods (e.g. foods, food ingredients, dietary supplements or food for special medical purposes), directly fed microorganisms (for animal use) and designer probiotics (genetically modified probiotics). Safety assessment of bacterial strains used as probiotics should be carefully studied. Even though probiotic bacteria have the generally recognized as safe (GRAS status), there are several reports about side effects triggered by the presence of these organisms. Microorganisms used as probiotics may cause systemic infections, stimulate the immune system, disturb metabolism and participate in horizontal gene transfer.

Assessment of the Microbiological Status of Probiotic Products.

The aim of this study was to perform the microbiological analysis of quality of 25 probiotic products, available on the Polish market. Analysis of bacterial viability in probiotic products showed that not all of these preparations possess a suitable number of bacteria. Moreover, some of the tested probiotic products contained bacterial strains other than those declared by the manufacturer. All tested strains recovered from probiotic products were found to be resistant to metronidazole and susceptible to nitrofurantoin. The susceptibility to other antibiotics was strain specific. Probiotic products should be subject to regular and thorough inspection by appropriate institutions.

Antibacterial activity of selected commercial products for mouth washing and disinfection, assessed in accordance with PN-EN 1040.

BACKGROUND: Currently, there is a wide range of products for mouth washing on the Polish market. They have different qualitative and quantitative compositions, and they differ particularly in the concentration of active substances. In antisepsis and disinfection, the significant reduction in number of cells of microorganisms in a particular environment is very crucial. The chemical agents should provide a significant decrease in number of microorganisms in a relatively short time. The purpose of this study was to examine the bactericidal activity of selected herbal products used for treatment of inflammation, and disinfection and washing of the mouth, having antibacterial activity as declared by the manufacturers. MATERIAL AND METHODS: The study included 28 products for mouth washing and disinfection available in Poland. Bactericidal activity was studied using a quantitative suspension test according to the standard PN-EN 1040. RESULTS: Only 1 of 4 tested herbal products, registered as medicinal products, showed satisfactory antibacterial activity when they were used according to the manufacturer's recommendations. A total of 13 preparations (48%) complied with the standard requirements against all tested strains. Up to 19% of products showed no bactericidal activity against bacterial strains, and up to 33% were only effective against certain microorganisms. CONCLUSIONS: The informational literature accompanying most antiseptics should be corrected by the manufacturers, providing information about antimicrobial activity consistent with the requirements of applicable standards. The information on the packaging or in the leaflets for antiseptic products should be corrected by the manufacturers to include accurate information on antimicrobial activity.

[Evaluation of biocidal properties of silver nanoparticles against cariogenic bacteria]. / Ocena bakteriobójczej aktywnosci koloidalnego roztworu nanoczastek srebra w stosunku do bakterii próchnicotwórczych.

INTRODUCTION: Antimicrobial properties of silver nanoparticles (SNP's) have been recentl well evaluated, and now are being considered as excellent candidates for therapeutic purposes. It is confirmed, that various solutions of colloidal SNP's possess significant antibacterial properties against such species as: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa even at low concentrations, although there have been so far only a few researches evaluating antimicrobial activity of SNP's against cariogenic bacteria: Streptococcus mutans, Streptococcus salivarius and Streptococcus mitis responsible for initiation of dental carries. Tooth decay is infectious disease an worldwide, which may occur in patients of every age. Nanotechnology creates a new approach of designing of medical devices preventing or reducing bacterial colonization. METHODS: Colloidal silver solution (CSS) of concentration 350 ppm was used in this research. Nanoparticles size, shape and solution stability were evaluated. 16 strains of cariogenic bacteria, 4 isolates of each species: S. mutans, S. salivarius, S. sanguinis and S, mitis were obtained from plaque swabs of 7 patients treated for dental carries at Department of Conservative Dentistry, Medical University of Warsaw. MIC and MBC values for CSS's were evaluated. RESULTS: CSS used in this research is of good stability. No agglomeration or coalescence was observed during 24 hours of experiment. Silver nanoparticles were of round shape and had mean size of 67 nm. MIC values were: 12-25 ppm for S. salivarius, 25 ppm for S. sanguinis, 50-100 ppm for S. mitis and 50 ppm for S. mutans, while MBC values after 1 hour of bacterial contact with nanoparticles were 200-350 ppm for all cariogenic bacterial species. After 24 hours of contact MBC values were: 25-50 ppm for S. salivarius and S. sanguinis, 100-200 ppm for S. mitis and 200 ppmfor S. mutans. CONCLUSIONS: Antimicrobial properties of CSS depend on nanoparticles concentration and interaction time with bacteria. The susceptibility of cariogenic oral streptococci to silver nanoparticles is diversified. Sufficient concentration which inhibited all cariogenic bacteria in our research was 200 ppm after long (24 hours) period of silver nanoparticles interaction with bacteria.

[Estimation of activity of pharmakopeal disinfectants and antiseptics against Gram-negative and Gram-positive bacteria isolated from clinical specimens, drugs and environment]. / Wrazliwosc wybranych szczepów bakterii Gram-ujemnych i Gram-dodatnich izolowanych z materialu klinicznego, leków i srodowiska, na farmakopealne zwiazki dezynfekcyjne i antyseptyczne.

The MIC of nine different disinfectants and antiseptics were determined for the Gram-negative and Gram-positive bacteria. Strains originated from clinical specimens, drugs and environment. A sensitivity was determined against chlorhexidinum digluconate (Gram-negative: 0,625-80 mg/L, Gram-positive: 0,3-10 mg/L), benzalconium chloride (Gram-negative: 2,5-1280 mg/L, Gram-positive: 1,25-20 mg/L), salicilic acid (Gram-negative and Gram-positive: 400-1600 mg/L), benzoic acid (Gram-negative: 800-1600 mg/L, Gram-positive: 400-1 600 mg/L), boric acid (Gram-negative: 800-12 800 mg/L, Gram-positive: 1 600-6400 mg/L), chloramine B (Gram-negative: 1600-6400 mg/L, Gram-positive:800- 6400 mg/L), jodine (Gram-negative: 200-1600 mg/L, Gram-positive: 200-1600 mg/L), etacridine lactate (Gram-negative: 40 do > 20480 mg/L, Gram-positive: 40-1280 mg/L) and resorcine (Gram-negative: 1600-6400 mg/L, Gram-positive: 800-6400 mg/L). Diversified values of MIC for different strains were obtained, especially in the case of benzalconium chloride, etacridine lactate, chlorhexidinum digluconate, boric acid and iodine. Strains isolated from environment were usually more susceptible to examined compounds than clinical strains. The biggest diversification of sensitivity was observed among strains originated from drugs where besides sensitive appeared strains characterizing by very high MIC values of some substances, eg. boric acid.

Analysis of phenoxymethylpenicillin potassium by capillary electrophoresis.

The application of capillary electrophoresis for separation of penicillin V and its impurities was investigated. The phosphate-borate buffer supplemented with sodium dodecyl sulfate (SDS) 20.0 g/L (69 mM) and pentanesulfonic acid sodium salt (PS) 2.2 g/L (12.5 mM) adjusted to pH 6.3, and current voltage 15 kV seem to provide optimal conditions for this aim. The resolution between penicillin V and each impurity was very good. The statistical analysis of phenoxymethylpenicillin V assay showed no significant differences between the results obtained by CE and HPLC methods.

Application of capillary electrophoresis to the determination of various benzylpenicillin salts.

The application of capillary electrophoresis for separation of benzylpenicillin, procaine, benzathine and clemizole was investigated. Phosphate-borate buffer supplemented with sodium dodecyl sulphate 14.4 g/l and electrophoresis voltage 18 kV seem to provide optimal conditions for micellar electrokinetic chromatographic assay of penicillin salts. This method is selective and precise. The results obtained from CE method recovery assay (above 98% for all but procaine-97% substances) and from determination of benzylpenicillin by CE compared with HPLC results, confirmed good accuracy.