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Bacterial Samples (bacterial + sample)
Selected AbstractsAn in-vitro investigation of the antibacterial effect of nisin in root canals and canal wall radicular dentineINTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2004S. R. Turner Abstract Aim, To determine whether nisin, a bacteriocin, would be effective at killing Enterococcus faecalis and Streptococcus gordonii cells in solution and within the root canal system. Methodology, Bacterial isolates of E. faecalis and S. gordonii were grown from glycerol stocks in closed tubes containing BHY broth at 37 °C. The minimum bactericidal concentration (MBC) of nisin for both bacterial species was determined by a microdilution method. Extracted human teeth were decoronated to produce roots of equal length with a single canal and divided into six groups of 10 roots. The canals were prepared to a master apical size 30 file using 0.04 taper Ni-Ti rotary instruments. Bacterial samples of each species were inoculated into three groups of prepared roots and incubated in closed tubes at 37 °C for 21 days. The root canals in each group were then medicated with water (control), calcium hydroxide powder mixed with sterile water [Ca(OH)2], or nisin and incubated for a further 7 days. Rotary Ni-Ti files were used to take radicular dentine samples from the walls of each canal which were then incubated in BHY broth for 24 h. Optical density (OD600) readings were taken as a measure of bacterial growth. Results, The MBC of nisin for E. faecalis and S. gordonii was 70 and 20 mg mL,1 respectively. Calcium hydroxide and nisin medication eradicated infection within the root canal while cells remained viable in the control group. Mean optical density (OD600) readings from canal wall dentine shavings infected with E. faecalis were 1.32 ± 0.98, 0.73 ± 0.27 and 0.69 ± 0.38 for the control, Ca(OH)2 and nisin samples respectively. Corresponding mean readings for S. gordonii were 1.19 ± 0.18, 0.73 ± 0.15 and 0.60 ± 0.29. The Ca(OH)2 and nisin group readings were significantly (P < 0.01) lower than the control for each species as tested by Student's t -test and Mann,Whitney U statistical analysis. Values for Ca(OH)2 and nisin were not significantly (P > 0.01) different. Conclusion, Nisin was effective at eradicating E. faecalis and S. gordonii cells in pure culture and was comparable with Ca(OH)2 in the elimination of these species from within the root canal system. [source] Critical aspects of analysis of Micrococcus luteus, Neisseria cinerea, and Pseudomonas fluorescens by means of capillary electrophoresisELECTROPHORESIS, Issue 18-19 2004Verena Hoerr Abstract Within the frame of our study we investigated Microccocus luteus, Neisseria cinerea, and Pseudomonas fluorescens by means of capillary zone electrophoresis (CZE). They form chains and clusters on a different scale, which can be reflected in the electropherograms. A low buffer concentration of Tris-borate and Na2 EDTA containing a polymeric matrix of 0.0125% poly(ethylene) oxide (PEO) was used. Key factors were the standardization and optimization of CE conditions, buffer solution, and pretreatment of bacterial samples, which are not transferable to different bacterial strains, in general. The different compositions of the cell wall of on the one hand Gram-positive (M. luteus) and Gram-negative (N. cinerea) cocci and on the other hand Gram-negative, rod-shaped bacteria (P.fluorescens), are probably responsible for the different pretreatment conditions. [source] Amplification of low quantity bacterial RNA for microarray studies: time-course analysis of Leptospirillum ferrooxidans under nitrogen-fixing conditions,ENVIRONMENTAL MICROBIOLOGY, Issue 6 2006Mercedes Moreno-Paz Summary We have developed a method for the amplification of low quantity total bacterial RNA for DNA microarrays analysis. Current methods are based on the linear amplification by the in vitro transcription from the T7 promoter, similar to that used for eukaryotic mRNA amplification. For the incorporation of T7 promoter, the prokaryotic RNA must be enzymatically modified for the incorporation of a polyA tail at the 3, end to emulate the eukaryotic mRNA. The method we describe and validate herein avoids this step by the direct and random incorporation of the T7 promoter. From 500 ng of total bacterial RNA, we obtained 130,150 µg of antisense RNA, such products being good substrate for fluorescent labelling and DNA microarray analysis. The method was validated with bacterial samples from which it is very difficult to obtain sufficient amounts and quality of total RNA for global gene expression analysis. This is critical for low cell density growing microorganisms, environmental samples, or many extremophiles where the composition of the cultural media severely affects the RNA yield, like in the case of the acidophile and iron oxidizer Gram-negative bacterium Leptospirillum ferrooxidans. We further validated our amplification method in parallel experiments with non-amplified RNA by following the expression of the L. ferrooxidans nif regulon along the time-course of growth. [source] Pyrolysis mass spectrometry for distinguishing potential hoax materials from bioterror agents,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 16 2006Jon G. Wilkes Pyrolysis mass spectrometry (PyMS) was investigated as a rapid tool to distinguish potential bioterror hoax materials from samples containing pathogenic bacteria. A pyrolysis time-of-flight (TOF) mass spectrometer equipped with an alternative ionization technique, metastable atom bombardment (MAB), was used to produce sample spectra. These spectra were analyzed by principal component and discriminant analysis for pattern recognition. Materials investigated were two strains of Vibrio parahaemolyticus, one of which produced the tdh toxin, two Salmonella enterica serotypes, a biological mosquito control product containing spores of Bacillus thuringiensis, and several white to off-white powders (which could be used as hoax materials), such as flour, corn starch, methyl cellulose, and xanthan gum. PyMS distinguished bacterial samples from hoax materials. Furthermore, pattern analysis differentiated Vibrios from Salmonellae, Salmonella enterica Anatum from S. enterica Heidelberg, and the two V. parahaemolyticus strains from each other. The B. thuringiensis mixture was distinguished from other bacteria and powders, suggesting that PyMS with pattern recognition may differentiate samples containing pathogens, including Bacillus spp., from nonbiological agents and that it can be a rapid method for detection of bacteria. MS data acquisition took only 7 min for each sample. Published in 2006 by John Wiley & Sons, Ltd. [source] The Diagnostic Utility of an Electronic Nose: Rhinologic ApplicationsTHE LARYNGOSCOPE, Issue 9 2002Erica R. Thaler MD Abstract Objective/Hypothesis The thesis explores the applicability of electronic nose technology in medical decision-making. Specifically, the studies undertaken in the thesis were designed to test the ability of the electronic nose to assist in diagnostic questions encountered in the field of rhinology. Study Design Three separate studies were undertaken. All involved analysis of specimens by the electronic nose, obtained either in vitro or in vivo: known matched sets of cerebrospinal fluid and serum, bacterial samples from known plated specimens, and culture swabs taken from patients suspected of having rhinosinusitis who also had a matched standard bacterial culture taken from the same site. The goal of analysis was to determine whether the electronic nose was able to identify or categorize specimens or groups of specimens. Methods Each specimen was tested using the organic semiconductor-based Cyranose 320 electronic nose. Data from the 32-element sensor array were subjected to principal-component analysis to depict differences in odorant patterns. Distinction of specimens was identified by calculation of Mahalanobis distance. Results The electronic nose was able to distinguish serum from cerebrospinal fluid in pure isolates as well as in isolates collected on small cottonoid pledgets at amounts of 0.2 mL or greater. It was also able to distinguish between control swabs and bacterial samples as well as among bacterial samples collected in vitro. Preliminary work suggests that it may be able to distinguish between presence and absence of bacterial infection in specimens collected on nasal swabs. Conclusions The electronic nose is able to distinguish reliably between cerebrospinal fluid and serum sampled in small amounts, may be able to identify presence and type of bacterial pathogen in vitro, and is able to identify presence or absence of bacteria on nasal swabs. Because this information is available immediately, the electronic nose may be a powerful new technology for diagnostic use, not only for rhinologic purposes but in many other aspects of medicine as well. [source] Clinical and microbiological analysis of subjects treated with Brånemark or AstraTech implants: a 7-year follow-up studyCLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2008S. Renvert Abstract Aims: To assess the impact of different implant systems on the clinical conditions and the microbiota at implants, and whether the presence of bacteria at tooth sites was predictive of the presence at implant sites. Materials and methods: Subjects with either AstraTech or Brånemark in function for 7 years were enrolled. Sub-gingival bacterial samples at tooth and implant sites were collected with sterile endodontic paper points, and analyzed by the checkerboard DNA,DNA hybridization method (40 species). Results: Fifty-four subjects, 27 supplied with AstraTech (n=132 implants) and 27 with Brånemark (n=102) implants, were studied. Test tooth sites had significantly less evidence of bleeding on probing (P<0.001) and presence of plaque (P<0.001) than implant test sites. Implant sites presented with deeper probing pocket depth than tooth sites (mean difference: 1.1 mm, standard error of differences: 0.08, 95% confidence intervals (CI): 0.9,1.3, P<0.001). Tannerella forsythia (P<0.05), Capnocytophaga sputigena (P<0.05), Actinomyces israelii (P<0.05) and Lactobacillus acidophilus (P<0.05) were found at higher levels at tooth surfaces. No differences in bacterial load for any species were found between the two implant systems. The odds of being present/absent at tooth and implants sites were only significant for Staphylococcus aureus [odds ratio (OR): 5.2 : 1, 95% CI: 1.4,18.9, P<0.01]. Conclusions: After 7 years in function, implants presented with deeper probing depths than teeth. S. aureus was commonly present at both teeth and implants sites. S. aureus at tooth sites was predictive of also being present at implant sites. [source] | |||||||||||||