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PubMed2006

Microbial colonization patterns predict the outcomes of surgical treatment of intrabony defects.

AIM: To explore the impact of bacterial load and microbial colonization patterns on the clinical outcomes of periodontal surgery at deep intrabony defects. MATERIALS AND METHODS: One hundred and twenty-two patients with advanced chronic periodontitis and at least one intrabony defect of >3 mm were recruited in 10 centres. Before recruitment, the infection control phase of periodontal therapy was completed. After surgical access and debridement, the regenerative material was applied in the test subjects, and omitted in the controls. At baseline and 1 year following the interventions, clinical attachment levels (CAL), pocket probing depths (PPD), recession (REC), full-mouth plaque scores and full-mouth bleeding scores were assessed. Microbial colonization of the defect-associated pocket was assessed using a DNA-DNA checkerboard analysis. RESULTS: Total bacterial load and counts of red complex bacteria were negatively associated with CAL gains 1 year following treatment. The probability of achieving above median CAL gains (>3 mm) was significantly decreased by higher total bacterial counts, higher red complex and T. forsythensis counts immediately before surgery. CONCLUSIONS: Presence of high bacterial load and specific periodontal pathogen complexes in deep periodontal pockets associated with intrabony defects had a significant negative impact on the 1 year outcome of surgical/regenerative treatment.

Alveolar Bone Loss↗
PubMed1992

Relationship between bacterial counts, microbial vitality and the accumulation of supragingival dental plaque in humans.

Comparisons between plaque index (PlI) and bacterial counts have been made already; however, these did not take into account the area used for plaque sampling. The objective of the present study was to determine the correlation between the PlI score, the number of bacteria and the bacterial plaque vitality when dental plaque was repeatedly sampled from the same area in each subject during early plaque accumulation. Between intervals of optimal oral hygiene, 10 participants refrained from all oral hygiene measures for periods of 1, 2, 3, 4 and 5 days. The PlI was recorded on the vestibular surface of all first premolars as local PlI:LS. For statistical reasons, the scores of the independent variable LS were added for each subject giving LS* values ranging from 0 to 8. The plaque sampled from this specific surface was circumscribed by the marginal gingiva and an acrylic splint, giving reproducible areas for plaque collection. Total microscopic bacterial counts (BC), colony forming units of anaerobes (CFUan) and aerobes (CFUae), and proportions of vital bacteria (VF) were compared with LS* values. BC and LS* values were strongly correlated. CFUan and CFUae increased significantly with LS*, but this increase was higher for LS* 0 to 4 than for LS* 4 to 8. The ratio between vital and dead microorganisms, assessed by two different methods, was low when an LS* of 0 was recorded, with higher ratios registered for LS* values 4 and 8.

Adolescent↗
PubMed2002

Microbial diversity and activity along the forefields of two receding glaciers.

Forefields of two receding glaciers were sampled along either a 150 or 200 m long transect at identical spatial intervals for assessment of soil microbial activity and community diversity trends. The forefields belonged to the Dammaglacier (forefield area is 157 ha, 2000 m above sea level) and Rotfirnglacier (100 ha, 2200 m) and at the time of sampling were receding at an estimated rate of 8 and 10 m yr(-1) over the past 5 years, respectively. Direct counting of bacteria (DAPI staining), assessment of dehydrogenase activity (DH), and fluorescein diacetate hydrolysis activity (FDA) were performed to estimate bacteria number and soil microbial activity. Along the Dammaglacier forefield (from youngest to oldest soil), bacteria number (8.21 x 10(7) to 1.49 x 10(9) cells g(-1) soil), DH activity (0 to 61 mg TTC reduced g(-1) soil h(-1)), and FDA activity (0 to 100 mg fluorescein produced g-1 soil h-1) increased, suggesting the development of microbial populations increasing in number and activity. The Rotfirn forefield exhibited similar trends per gram of soil in bacteria number (1.13 x 10(8) to 5.93 x 10(9) cells), DH activity (0 to 36 mg TTC reduced), and FDA activity (2 to 70 mg fluorescein produced), but with more variability among samples than the Damma forefield samples. Molecular assessment of bacterial diversity included denaturing gradient gel electrophoresis (DGGE) and ribosomal intergenic spacer analysis (RISA) of soil DNA. DGGE and RISA revealed that the composition and succession of bacterial populations were different in both forefields. Comparison of Shannon diversity index values indicated that all populations sampled from the Damma forefield were significantly different (p < 0.05). Conversely, similar populations existed in the Rotfirn forefield succession. Overall, the results indicate that diverse bacterial assemblages increasing in number and activity characterize these glacier forefield soils with both forefield successions exhibiting differing modes of bacterial community establishment.

Bacteria↗
PubMed1989

[Clinical study of the correlation between bad breath and subgingival microflora].

A dark field microscopic examination of subgingival microorganisms and gas chromatographic analysis of volatile sulphur compounds were employed to investigate the role of subgingival microflora in the production of bad breath. Subjects (11 female, 13 male; aged 24 to 61) were divided into the following 2 groups on the basis of apparent bad breath by the olfactory judgement; bad breath group (group B, n = 13), and no bad breath group (group N, n = 11). A gas tight syringe was employed to withdraw 5 ml mouth air samples, which were injected directly into the gas chromatograph. Volatile sulphur compounds produced in mouth air were analyzed by gas chromatograph to determine volumes of CH3SH. Subgingival plaque samples were taken with sterilized paper points from the deepest site of probing depth in each subjects. The samples were examined by means of dark field microscopy and 100 bacteria in randomly selected fields were classified on a percentage basis into one of the following morphological categories: (1) spirochetes, (2) motile rods, (3) filaments, (4) fusiforms, (5) straight rods, and (6) coccoid cells. Total cell counts per 1 ml were calculated from bacterial counts of each categories. Comparison of 2 independent means from each groups were carried out by Wilcoxon's rank sum test for nonparametric values. Correlations of bacterial data with CH3SH values in mouth air were determined by means of Spearman rank correlation cofficient. Results were as follows; 1. Significant differences existed in the microbial flora between the 2 groups: percentage of spirochetes and motile rods in group B were significantly higher than those in group N (p less than 0.01). Total cell counts of group B were significantly greater than group N, and there were statistically significant differences (p less than 0.01). 2. CH3SH values in mouth air had positive correlations with the percentage of spirochetes, the percentage of motile rods, and total cell counts. These results are consistent with the view that subgingival microorganisms play a certain role in the production of bad breath. Moreover, it was suggested that spirochetes and motile rods are related to the mechanism of bad breath production.

Adult↗
PubMed2006

Quantification of mucosa-adhered microbiota of lambs and calves by the use of culture methods and fluorescent in situ hybridization coupled with flow cytometry techniques.

The intestinal mucosa-associated microbiota could play important biological roles due to its close proximity with the animal host, but knowledge on its composition is still limited. The aim of this study was to characterize the microbial communities tightly associated with different parts (rumen, duodenum and colon) of the gastrointestinal tract (GIT) of healthy lambs and calves by using both cultural, and fluorescent in situ hybridization-flow cytometry (FCM-FISH) techniques. Lactic acid bacteria genera were one of the predominant bacteria detected in lambs and calves by both methodologies, possibly constituting an index of their healthy status. The levels of Lactobacillus were significantly higher (p<0.05) in the rumen and duodenum of lambs, and in the rumen of calves. The levels of Bifidobacterium were significantly higher (p<0.05) in the colon of both animal species and the rumen of lambs. Significant differences (p<0.05) were found in counts of other microbial groups (yeast, Enterococcus, Propionibacterium, Bacteroides, Clostridium and Enterobacteriaceae) at diverse GI sections depending on the animal species. In general, microbial counts follow the same trends regardless the applied technique. The most remarkable differences were found in detection levels of Bacteroides and Clostridium, which tended to be significantly higher (p<0.05) when analysed by FCM-FISH. This technique also allowed the detection of quantitatively important bacteria (sulphate-reducing bacteria, Atopobium and Coriobacterium), which are difficult to cultivate in selective medium. Therefore, FCM-FISH has been proven to be a sensitive high throughput approach that provides additional information to that obtained by traditional culture techniques about the complexity of the GI ecosystem of these animal species.

Animals↗
PubMed2005

Monitoring of antibiotic-induced alterations in the human intestinal microflora and detection of probiotic strains by use of terminal restriction fragment length polymorphism.

Terminal restriction fragment length polymorphism (T-RFLP) was investigated as a tool for monitoring the human intestinal microflora during antibiotic treatment and during ingestion of a probiotic product. Fecal samples from eight healthy volunteers were taken before, during, and after administration of clindamycin. During treatment, four subjects were given a probiotic, and four subjects were given a placebo. Changes in the microbial intestinal community composition and relative abundance of specific microbial populations in each subject were monitored by using viable counts and T-RFLP fingerprints. T-RFLP was also used to monitor specific bacterial populations that were either positively or negatively affected by clindamycin. Some dominant bacterial groups, such as Eubacterium spp., were easily monitored by T-RFLP, while they were hard to recover by cultivation. Furthermore, the two probiotic Lactobacillus strains were easily tracked by T-RFLP and were shown to be the dominant Lactobacillus community members in the intestinal microflora of subjects who received the probiotic.

Anti-Bacterial Agents↗
PubMed2004

A survey of microbial contamination of food contact surfaces at broiler slaughter plants in Taiwan.

Microbial contamination levels at broiler slaughter plants were investigated at three major slaughter plants in Taiwan during the summer and winter. The microbial contamination levels in chicken carcasses and on food contact surfaces were examined using the swab method. The results indicated that the bacterial counts were affected by the slaughter processing plant, processes, and season (P < 0.05). The bacterial counts on food contact surfaces of the equipment before operation were not significantly lower than those after processing. Regardless of the bacterial type, bacterial counts of chicken carcasses generally decreased from the scalding step to the washing step before evisceration and then increased. The cleaning procedures for food contact surfaces should be evaluated, and special attention should be given to utensils used during processing, such as gloves, baskets, and hand tools.

Abattoirs↗
PubMed2003

Measurement of fungi by an indirect conductimetric assay.

AIMS: To investigate the growth of fungi using an indirect conductimetric assay and derive, experimentally and theoretically, the relationship between microbial concentration and electrical conductivity change. METHODS AND RESULTS: The indirect assay, in which change in electrical conductivity of an alkaline solution (NaOH) is produced by absorption of CO2 from microbial metabolism, was conducted with the Bactometer (bioMerieux, Marcy-l'Etoile, France) for the enumeration of fungi. A linear relationship was obtained between detection time and logarithmic initial microbial concentration. This indirect assay used growth media, which could not be used in the direct conductimetric assay, to monitor fungal growth. CONCLUSIONS: The indirect assay does not depend on the growth media and the turbidity of sample and could offer a simple and rapid assay for the measurement of fungal growth under various conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: The indirect assay is applicable for rapid detection of fungi, estimation of the growth rate and evaluation of antifungal activity.

Colony Count, Microbial↗
PubMed1999

Microbial control of the culture of Artemia juveniles through preemptive colonization by selected bacterial strains.

The use of juvenile Artemia as feed in aquaculture and in the pet shop industry has been getting more attention during the last decade. In this study, the use of selected bacterial strains to improve the nutritional value of dry food for Artemia juveniles and to obtain control of the associated microbial community was examined. Nine bacterial strains were selected based on their positive effects on survival and/or growth of Artemia juveniles under monoxenic culture conditions, while other strains caused no significant effect, significantly lower rates of survival and/or growth, or even total mortality of the Artemia. The nine selected strains were used to preemptively colonize the culture water of Artemia juveniles. Xenic culture of Artemia under suboptimal conditions yielded better survival and/or growth rates when they were grown in the preemptively colonized culture medium than when grown in autoclaved seawater. The preemptive colonization of the culture water had a drastic influence on the microbial communities that developed in the culture water or that were associated with the Artemia, as determined with Biolog GN community-level physiological profiles. Chemotaxonomical characterization based on fatty acid methyl ester analysis of bacterial isolates recovered from the culture tanks was performed, and a comparison with the initially introduced strains was made. Finally, several modes of action for the beneficial effect of the bacterial strains are proposed.

Animals↗
PubMed1975

Effects of solar ultraviolet radiations on Bacillus subtilis spores and T7 bacteriophage.

Spores of Bacillus subtilis HA 101 and the DNA polymerase I-defective mutant HA 101 (59) F were exposed to selected wavelengths of solar ultraviolet light and space vacuum during the return of Apollo 16. In addition, coliphage T7 suspensions were exposed to solar ultraviolet radiation as part of the Microbial Response to Space Environment Experiment. Optical filters were employed to provide different energy levels at wavelengths 254 nm and 280 nm. Dose-response curves for lethal and mutagenic effects were compared with ground-based data. A close parallel was observed between the results of solar radiation and ground tests with spores of the two strains. However, significantly greater inactivation of T7 bacteriophage was observed after exposure to solar ultraviolet radiation.

Bacillus subtilis↗
PubMed2004

Preliminary results for a new final package test to assess the quality of sterile package systems.

OBJECTIVES: To develop a microbial test method to ascertain the passage of airborne bacteria through the medical device packaging system after sterilization, and to apply this test method to flexible packages under mechanical pressure changes. METHODS: Petri dishes filled with nutrient agar were integrated into the packaging unit prior to sterilization. We examined paper packaging consisting of 1 (single-paper packaging [P]), 2 (double-paper packaging [PP] and textile and paper double packaging [TP]), and 3 (double packaging with transport packaging [TPP]) layers. After sterilization, the test packages were pressed five times per minute for 1 or 3 hours by a mechanical device weighing 1 kg. This exposure took place in rooms with an average airborne bacterial count of 35 (room 1) or 440 (room 2) CFU/m3. The packaging was opened following culture at 37 degrees C for 48 hours to determine the number of colonies formed. RESULTS: The proportion of contaminated packages rose with the duration of mechanical stress and increased airborne bacteria concentration. Thus, mechanical pressure change for 3 hours resulted in the contamination of 60% (P), 15% (PP), 0% (TP), and 0% (TPP) of the packages in room 1, whereas 100% (P), 65% (PP), 73% (TP), and 0% (TPP) of the packages in room 2 were contaminated. CONCLUSIONS: This test method allows sterile packaging systems to be tested for contamination under practical conditions without extensive laboratory preparation. Contamination as a result of laboratory errors can be ruled out almost certainly.

Central Supply, Hospital↗
PubMed2005

Effect of gamma irradiation on microbial growth and sensory quality of fresh-cut lettuce.

Fresh-cut lettuce was irradiated and microbiological and sensory quality was examined during storage at 4 degrees C. Experimental results showed that the number of aerobic mesophilic bacteria on fresh-cut lettuce irradiated with 1.0 kGy was reduced by 2.35 logs and sensory quality was maintained best during storage for 8 days at 4 degrees C. It was indicated that Gompertz model could predict the bacterial number on fresh-cut lettuce if the initial level was known.

Bacteria↗
PubMed1993

Effect of freezing and mincing technique on microbial load of minced meat.

This experiment was carried out to explain the variation between the use of either fresh or frozen meat cuts in manufacturing of minced meat; in this connection the role of the mincer and the hygienic condition of handling as well as of the temperature under which the raw material and product was handled should be investigated. The achieved results indicated that the minced meat manufactured from fresh meat has low microbial load as compared with that produced from frozen one. However, the mincing at butcher's shops may expose the meat to more sources of contamination than that minced at home (self-made mincing). The handling of raw meat either fresh or frozen in butcher's shops exposed the produced minced meat to high numbers of either spoilage or food poisoning microorganisms. The sources of contamination of produced minced meat were discussed.

Animals↗
PubMed1999

Deoxycholate-hydrogels: novel drug carrier systems for topical use.

Na-deoxycholate (Na-DOC) forms a viscous thixotropic gel when in contact with excess buffer systems. The resulting gels have been tested as novel drug carrier systems for topical use. The influence of differing amounts of mannitol, glycerol and xylitol on the viscous modulus (G"/Pa) was evaluated by oscillatory measurements. Na-DOC (0.5%) in phosphate buffered saline (PBS) with 5% mannitol was chosen as an optimised formulation, taking into account viscosity, distribution and appearance. The release rate of the model drug rutin through an artificial membrane was higher than those from hydroxyethylcellulose- (HEC) and sodium polyacrylate (NaC934)-gels; permeation through excised rat skin was also highest for the Na-DOC systems. The results indicate that Na-DOC significantly increases the membrane permeability. The microbial stability was in the same range as HEC- and NaC934-gels, making a preservation necessary. Na-DOC-gels are novel low molecular weight, multifunctional drug carriers, which also act as penetration enhancers. Their thixotropy is an additional advantage for better application to large skin areas, nasal, vaginal and buccal membranes. Therefore, Na-DOC-gels can be considered promising, alternative drug carrier systems for topical pharmaceutical as well as cosmetic use.

Administration, Cutaneous↗
PubMedDate not supplied

Microbiologic survey of prosthetic blood pumps presterilization and poststerilization and at explant retrieval.

Device-associated infection remains a major complication of implanted total artificial hearts (TAH). The possibility of microbes being introduced on the device was investigated by conducting a gross microbial assay, pre- and poststerilization, and following explant retrieval. Culture samples were obtained from the housing, base, and blood-contacting diaphragm of Utah-100 artificial ventricles. Additional samples were obtained from atrial sewing cuffs, outflow grafts, drive lines, and percutaneous leads, along with reference control samples prior to ethylene oxide sterilization (ETO). Culturing was repeated poststerilization and at device explant retrieval. Positive bacterial and fungal cultures were found in 24% of the presterilization samples; in the poststerilization samples, positive cultures were found in 6%. Following device explant retrieval, 84% of the cultures were positive. The reference control samples were positive in a limited number of the poststerilization samples. There was no correspondence of the species of micro-organisms found at the same location for each sampling condition. These data demonstrate that the surfaces of the TAH can become contaminated during fabrication. The presence of microbial activity poststerilization raises the possibility of inadequacy of the ETO protocol used with these devices, or contamination of the surgical field. Hearts at explant retrieval had cultures positive for microbes differing from those identified prior to implantation. This finding suggests that device-associated micro-organism colonization occurs through a source other than manufacturing or surgical contamination.

Animals↗
PubMed2002

Inactivation of the antibacterial activity of iodine potassium iodide and chlorhexidine digluconate against Enterococcus faecalis by dentin, dentin matrix, type-I collagen, and heat-killed microbial whole cells.

The antibacterial activity of chlorhexidine digluconate and iodine potassium iodide on Enterococcus faecalis A197A was tested in the presence of dentin, dentin matrix, dentin pretreated by EDTA and citric acid, collagen, and heat-killed cells of Enterococcus faecalis and Candida albicans. Medications were preincubated for 1 h with each of the potential inhibitors and tested for their antibacterial activity against E. faecalis, strain A197A. Surviving bacteria were sampled after 1 and 24 h of incubation. Dentin matrix and heat-killed microbial cells were the most effective inhibitors of chlorhexidine, whereas dentin pretreated by citric acid or EDTA showed only slight inhibition. Dentin and skin collagen showed some inhibition at 1 h but not after 24 h. Iodine potassium iodide was effectively inhibited by dentin, dentin matrix, and heat-killed microbial cells. Skin collagen and dentin pretreated by EDTA or by citric acid showed little or no inhibitory effect on iodine potassium iodide. Different components of dentin are responsible for the divergent patterns of inhibition of the antibacterial activity of chlorhexidine digluconate and iodine potassium iodide. Chemical treatment of dentin before applying the medication into the root canal may alter the antibacterial effect of the medication.

Candida albicans↗
PubMed1998

Effectiveness of cleaning and disinfection procedures on the removal of enterotoxigenic bacillus cereus from infant feeding bottles.

Reconstituted infant milk formulas are considered a food class of high risk because of the susceptibility of the infant population to enteric bacterial pathogens, severe response to enterotoxins, and increased mortality. Twenty infant feeding bottles, contaminated with different levels of enterotoxigenic Bacillus cereus, were subjected in triplicate to a variety of commonly used cleaning and disinfection procedures Although thorough cleaning reduced microbial numbers, it did not remove all B. cereus present. Three commercially available disinfection procedures (i.e., one chemical and two thermal) successfully eliminated this organism when the level of contamination was <10(5) organisms ml(-1). However, the chemical disinfection method failed to eliminate enterotoxigenic B. cereus totally at potentially hazardous contamination levels (i.e., greater than or equal to 10(5) organisms ml(-1)) that may be encountered under storage abuse conditions in the home.

Animals↗
PubMed2004

Phenotypic and genotypic identification of Aeromonas spp. isolated from a chlorinated intermittent water distribution system in Lebanon.

Aeromonas spp. were detected in samples collected from both untreated groundwater and treated drinking water in Lebanon. Aeromonas spp. levels ranged between 2 and 1,100 colonies per 100 ml in the intake underground well and between 3 and 43 colonies per 100 ml in samples from the distribution system. Samples positive for Aeromonas spp. from the network had a free chlorine level ranging between 0 and 0.4 mg l(-1). Multiple antibiotic-resistance was common among the isolated aeromonads; all were resistant to amoxycillin while 92% showed resistance to cephalexin. Haemolysis on blood agar was detected in 52% of the isolates recovered from the distribution network and 81% of isolates from the untreated underground source. The Biolog microbial identification system assigned identities to all of the isolated presumptive aeromonads (at least at the genus level), which was not the case with the API 20NE strips. Differences at the species level were observed when results from the Biolog system were compared with identification based on the MicroSeq 500 16S rDNA sequence analysis. The presence of Aeromonas spp. in drinking water can be an important threat to public health, thus greater awareness of Aeromonas strains as potential enteropathogens is warranted.

Aeromonas↗