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PubMed2001

In vitro fermentation characteristics of native and processed cereal grains and potato starch using ileal chyme from dogs.

Two in vitro experiments were conducted to evaluate the ability of small intestinal bacteria of dogs to ferment native and extruded cereal grains and potato starch and cereal grain and potato flours. Substrates included barley, corn, potato, rice, sorghum, and wheat. In addition to testing native grains and flours, extruded substrates also were tested. Substrates were extruded at low temperatures (LT; 79 to 93 degrees C) and high temperatures (HT; 124 to 140 degrees C) using a Wenger extruder (model TX-52). Substrates varied widely in concentrations of rapidly digestible starch (RDS), slowly digestible starch (SDS), resistant starch (RS), and total starch (TS). Extrusion of most substrates at HT vs LT resulted in increased RDS and decreased RS concentrations. Organic matter disappearance (OMD) values attributed to microbial fermentation for a 5-h period were as high as 27% for native extruded substrates (LT potato starch) and 39% for potato flour. Average OMD was higher for cereal and potato flours than for native extruded substrates (29.9 vs 25.4%). Average molar percentages of short-chain fatty acids produced from all substrates fermented for 5 h were 73, 14, and 13% (acetate, propionate, and butyrate, respectively). Average lactate production for substrates ranked as follows: flours > native and extruded cereal grains and potato starch (0.33 and 0.18 mmol/g OM, respectively). In vitro microbial fermentation of starches by ileal bacteria can be substantial and is affected by differences in starch source, fraction, and processed form.

Animals↗

PubMed2004

Intensive investigation of bacterial foodborne disease outbreaks: proposed guidelines and tools for the collection of dose-response data by local health departments.

Local health departments that investigate foodborne disease outbreaks do not have adequate guidelines for collecting data that could be used to estimate dose-response relationships, a key component of hazard characterization in quantitative microbial risk assessment. To meet this need, criteria and a questionnaire template for the collection of appropriate dose-response data in the context of outbreaks were developed and applied in the investigation of a point-source outbreak linked to Salmonella serotype Enteritidis in a salmon entrée in February 2000. In this outbreak, the attack rate and risk of hospitalization increased with the amount of salmon entrée consumed, and detailed data were obtained on illness severity measures and host susceptibility factors. Local health departments might consider broadening investigations to include the collection of additional data when investigating outbreaks that have met a specific set of conditions. These data could provide information needed by federal regulatory agencies and other organizations for quantitative microbial risk assessment. Intensive investigations of outbreaks could prevent future illnesses by providing information needed to develop approaches to minimizing risk.

Chicago↗

PubMed2001

Efficacy of chitosan, carvacrol, and a hydrogen peroxide-based biocide against foodborne microorganisms in suspension and adhered to stainless steel.

The ability of natural compounds to inactivate foodborne organisms adhered to surfaces was investigated with the ultimate aim of replacing synthetic biocides by more environmentally friendly, natural alternatives. The antimicrobial efficacy of 0.5, 1.0, and 2.0% chitosan and Spor-Klenz RTU (a commercial biocide based on hydrogen peroxide and peroxyacetic acid) and 0.5, 1.25, and 2.0 mM carvacrol was determined at 20 degrees C against Listeria monocytogenes, Salmonella enterica serovar Typhimurium, Staphylococcus aureus, and Saccharomyces cerevisiae adhered to stainless steel disks. Treatment with up to 2.0% chitosan reduced the viable cell count in the microbial films of the four test organisms by 2.4, 1.8, 2.3, and 0.9 log CFU/test surface (t.s.), respectively. By contrast, planktonic counts of the same organisms were reduced by 0.8 to 1.7 log CFU/ml at 2.0% chitosan. Treatment with 2 mM carvacrol reduced the viable counts of adhered listeriae, salmonellae, and yeasts by 2 to 3 log CFU/t.s. but S. aureus counts were reduced by only 0.9 log CFU/t.s. The efficacy of any single compound was species specific. In the case of microbial films prepared using listeriae and salmonellae, Spor-Klenz RTU was most biocidal, followed by carvacrol and then chitosan. However, dried films of S. aureus were most sensitive to chitosan and relatively resistant to carvacrol and Spor-Klenz RTU. By contrast, yeast films were most sensitive to carvacrol and least sensitive to chitosan. It was concluded that carvacrol and chitosan may have potential for use as natural biocides although optimization of conditions would be necessary.

Bacteria↗

PubMed2000

Characterization of whey cheese packaged under vacuum.

Vacuum packaging was assayed at 4 degrees C and was tested in comparison to unpackaged counterparts, in both microbiological and physicochemical terms, in studies pertaining to the preservation of Requeijão, a traditional Portuguese whey cheese. Bacteria were absent (i.e., <10 CFU/g) in whey cheeses on the day of manufacture as a result of thermal processing. After storage, both unpackaged and packaged cheeses exhibited high viable counts of Bacillus, Pseudomonas, Enterobacteriaceae, and lactic acid bacteria (especially lactococci). Yeasts, staphylococci, enterococci, and spore-forming clostridia were severely inhibited by the package vacuum combined with the increasing acidification developed therein. Whey cheeses packaged under vacuum underwent substantial acidification, slight depletion of lactose, and no significant variation in moisture content or texture; conversely, unpackaged whey cheeses exhibited substantial loss of water and a concomitant increase in rigidity. Vacuum packaging strongly inhibited lipolysis (even if viable counts of some microbial groups were high); saturated fatty acids (mainly C16:0 and C14:0) accounted for ca. 73% of the total free-fatty acid content, whereas the most concentrated unsaturated fatty acids were C18:1 and C18:2 (ca. 14% each). The conclusions generated in our study are, in general, useful for a wide range of whey cheeses worldwide: i.e., Requéson (Spain), Ricotta (Italy), Broccio (France), and Anthotyro (Greece). In addition, our conclusions are particularly helpful in terms of improving the safety of Requeijão, a widely acclaimed dairy specialty.

Cheese↗

PubMed1993

Microbial accumulation and vitality on different restorative materials.

A new technique using standardized test facings was designed to evaluate interdental plaque accumulation on different restoration materials. In 10 volunteers, a total of 40 samples, including enamel, two different ceramics and a bonding composite, were inserted one by one into a precision attachment in an experimental inlay bordering on either the lower second premolar or the lower first molar. Bacterial accumulation on each approximal specimen was allowed to mature for 3 d. Following microbiological processing of the plaque samples, total bacterial counts, colony forming units and the bacterial vitality were determined. The results revealed different accumulation rate patterns. Both ceramics accumulated less plaque with a reduced vitality compared to enamel, while the bonding composite showed no significant differences compared to the natural tooth substance. No significant differences were detected when comparing the two examined ceramics.

Adult↗

PubMed1996

Clinical/biological outcomes of treatment for pericoronitis.

PURPOSE: This prospective clinical study was designed to determine the clinical and biologic outcomes of treatment for minor signs and symptoms of pericoronitis. PATIENTS AND METHODS: Patients (n = 20) with all third molars, presenting consecutively to an academic clinical center for treatment of minor signs and symptoms of pericoronitis, were enrolled in the study. At the initial visit, gingival crevicular fluid (GCF) samples to assess levels of the cytokines interleukin- 1b (IL-1b) IL-1b and prostaglandin E2 (PGE2) as a measure of the host inflammatory response, and plaque samples to identify microorganisms, were collected from the distal of all second molars and the mesial of first molars. Standardized vertical bite wing radiographs were taken to assess alveolar bone height on the distal of the second molars and the inclination and the degree of eruption of the third molar. Full-mouth periodontal probing was conducted to determine probing depths and relative clinical attachment levels (CAL). Pain levels were assessed with Gracely verbal descriptor scales for sensory intensity and unpleasantness and 10-cm visual analog scales. Symptomatic third molar sites were treated with local debridement and irrigation after baseline data collection. One week after entry, data were collected again. Subsequently, the patients were scheduled for removal of all third molars. Data collection was repeated 3 months postsurgery. As controls, data were collected from 12 subjects who had asymptomatic third molars removed previously. RESULTS: At entry, symptomatic mandibular third molars (n = 21) were mostly vertical (n = 18) and at or above the occlusal plane (n = 19). No maxillary teeth had symptoms. Microbial counts were elevated for specific anaerobic microorganisms. GCF IL-1b levels were elevated at the distal of second molars adjacent to symptomatic third molars, as compared with asymptomatic third molars and second molars in control patients. Alveolar bone levels and CAL on the distal of second molars were normal. At 1 week, patients' pain symptoms and IL-1b levels were reduced, but microbial counts remained high. Three months after surgery, patients had no pain symptoms, and alveolar bone levels and CAL were similar to entry levels. IL-1b levels were elevated at both the distal of second molars and the mesial of first molars for all patients; microbial counts decreased, although not to levels of control patients. No increase in microbial counts for Porphyromonas gingivalis or Bacteroides forsythus, or GCF PGE2 levels, risk factors for progressive periodontal disease, was detected in samples taken from the study patients. CONCLUSION: Pericoronitis expressed by minor signs/symptoms in these patients was associated with considerable discomfort. Symptomatic mandibular third molars were vertical and at or near the occlusal plane. Additionally, this condition was characterized by microbial flora and GCF inflammatory mediator levels that are more consistent with gingivitis than periodontitis. Removal of third molars eliminated symptoms, but the microbial burden and an affected patient's inflammatory response, as measured by IL-1b levels, remained elevated as compared with controls. Further study is needed to determine which of these factors can be used to identify patients at risk for pericoronitis before symptoms arise.

Adolescent↗

PubMed2004

Microbial quality of tilapia reared in fecal-contaminated ponds.

The microbial quality of tilapia reared in four fecal-contaminated fishponds was investigated. One of the fishponds (TDP) received treated sewage with an average fecal coliform count of 4 x 10(3)cfu/100mL, and feed of fresh duckweed grown on treated sewage was used. The number of fecal coliform bacteria attached to duckweed biomass ranged between 4.1 x 10(2) and 1.6 x 10(4)cfu/g fresh weight. The second fishpond (TWP) received treated sewage, and the feed used was wheat bran. The third fishpond (FDP) received freshwater, and the feed used was the same duckweed. Pond 4 (SSP) received only settled sewage with an average fecal coliform count of 2.1 x 10(8)/100mL. The average counts in the fishponds were 2.2 x 10(3), 1.7 x 10(3), 1.7 x 10(2), and 9.4 x 10(3)cfu/100mL in TDP, TWP, FDP, and SSP, respectively. FDP had a significantly (P < 0.05) lower fecal coliform count than the treated sewage-fed ponds and SSP. The microbial quality of the tilapia indicated that all tissue samples except muscle tissues were contaminated with fecal coliform. Ranking of the fecal coliform contamination levels showed a decrease in the order intestine>gills>skin>liver. Poor water quality (ammonia and nitrite) in SSP resulted in statistically higher fecal coliform numbers in fish organs of about 1 log(10) than in treatments with good water quality. Pretreatment of sewage is therefore recommended.

Analysis of Variance↗

PubMed1996

Bacterial colonization as a potential source of nosocomial respiratory infections in two types of spirometer.

The potential risk of spirometers in the transmission of respiratory infections has not been yet established. We performed a prospective cross-sectional study to determine the rate of colonization of a water-sealed spirometer and a pneumotachograph, and the potential risk of cross-transmission of microorganisms to patients using each of these devices. Fifty four patients (aged 51 +/- 18 (mean +/- SD) yrs) were included in the study. All of them had undergone forced spirometry with bronchodilator response by means of the water-sealed spirometer (n = 36) or the pneumotachograph (n = 18). None had a clinically apparent respiratory infection at the time of the study. Routine hygiene measures for respiratory equipment were performed before the study protocol. Samples for microbiological cultures of different parts both of the water-sealed spirometer (proximal and distal tubing, bell and water-bell) and pneumotachograph (proximal and distal tubing) were taken daily before and after the usual series of lung function tests during a 5 day period. Pharyngeal swab cultures were obtained before spirometry and 7 days later in each subject. Thirty six out of a total of 40 (90%) culture samples from the water-sealed spirometer showed microbial growth compared to 4 out of 30 (13%) samples obtained from the pneumotachograph (p < 0.0001). Significant colonization of the water-sealed spirometer was apparent after the third day of the study. The microorganisms most frequently isolated were penicillium sp. (62%), Pseudomonas fluorescens (32%), and Burkholderia cepacea (48%). Distal tubing, water and water-bell were the parts of the water-sealed spirometer that showed higher colonization counts (> or = 10(4) colony-forming units (cfu).mL-1). No transmission sequence of potentially pathogenic microorganisms from equipment to patients or vice versa could be demonstrated. In summary, the water-sealed spirometer frequently became colonized by microorganisms. The potential hazard of such equipment as reservoirs of microorganisms suggests a need for the implementation of new hygiene measures for their maintenance.

Bacterial Infections↗

PubMed1998

Stimulated salivary flow rate and composition in asthmatic and non-asthmatic adults.

The number of decayed, missed and filled permanent teeth (DMFT), the degree of periodontal inflammation (Periodontal Status Index, PSI), stimulated salivary flow rate and the concentrations of total protein, lactoferrin, lysozyme, myeloperoxidase, salivary peroxidase, calcium, potassium, sodium and thiocyanate in whole saliva of 26 adult asthma patients were compared with those of 33 non-asthmatic controls. The saliva was also analysed for mutans streptococci, lactobacilli, total anaerobic flora and Candida spp. The mean PSI (p < 0.05; 95% confidence interval for the difference between means (95% CI) 2.47-25.30) was higher and the mean stimulated salivary flow rate (p < or = 0.05; 95% CI 0.57-0.55) was lower in the asthmatic group than in the control group. No differences were found between the groups in non-immune defense factors, except for myeloperoxidase. The myeloperoxidase concentrations were higher in asthmatics than in non-asthmatics (p < 0.05; 95% CI 4.4-134.0 ng/ml). No differences in microbial counts were found. It was concluded that stimulated salivary flow rates decrease while myeloperoxidase concentrations increase in adult asthmatic patients compared with non-asthmatic adults. The higher concentrations of myeloperoxidase are explained by a higher PSI in asthmatics.

Adult↗

PubMed2000

Monitoring the microbial contamination of beef carcass tissue with a rapid chromogenic Limulus amoebocyte lysate endpoint assay.

A chromogenic Limulus amoebocyte lysate (LAL) endpoint assay was found to be an accurate and rapid means of gauging levels of beef carcass microbial contamination within 10 min. The assay demonstrated a high correlation with the total mesophilic bacterial and coliform surface populations from inoculated beef carcass surface tissues. This assay was tested on a set of actual beef carcass surface samples (n = 121) demonstrating the utility of the chromogenic LAL test as a means of monitoring carcass microbial contamination in a near real-time fashion. Classifying the chromogenic LAL results into four contamination groups was found to be a sound means of utilizing the resultant chromogenic LAL data for detecting carcasses with high levels of microbial contamination. For beef carcass testing, this assay can be used with no instrumentation other than the required 37 degrees C incubator and, as an option, a microplate reader.

Abattoirs↗

PubMed2006

A combination of a transforming growth factor-beta antagonist and an inhibitor of cyclooxygenase is an effective treatment for murine pulmonary tuberculosis.

Transforming growth factor-beta (TGF-beta) and prostaglandins (PG) regulate the cell-mediated immune response, so it has been proposed that they affect the progression of pulmonary tuberculosis. Here we report that the administration of soluble betaglycan, a potent TGF-beta antagonist, and niflumic acid, a PG synthesis inhibitor, during the chronic phase of experimental murine tuberculosis enhanced Th1 and decreased Th2 cytokines, increased the expression of iNOS and reduced pulmonary inflammation, fibrosis and bacillary load. This immunotherapeutic approach resulted in significant control of the disease comparable to that achieved by anti-microbial treatment alone. Importantly, the combination of immunotherapy and anti-microbials resulted in an accelerated clearance of bacilli from the lung. These results confirm that TGF-beta and PG have a central pathophysiological role in the progression of pulmonary tuberculosis in the mouse and suggest that the addition of immunotherapy to conventional anti-microbial drugs might result in improved treatment of the disease.

Animals↗

PubMed1998

Airborne fungi and their secondary metabolites in working places in a compost facility.

The present study investigates in detail the exposure to airborne fungal spores in working places in compost facilities. The fungal species composition in the air is compared with the spectrum of microbial metabolites with regard to the physiological properties of different fungal species. The results indicate that the spectrum of microbial volatile organic compounds (MVOCs) and the production of mycotoxins can be specific for certain species. In addition to the pathogenic and allergological relevance, the fungi may have different toxicological health impacts.

Air Microbiology↗

PubMed2006

Sheep-urine-induced changes in soil microbial community structure.

Soil microbial communities play an important role in nutrient cycling and nutrient availability, especially in unimproved soils. In grazed pastures, sheep urine causes local changes in nutrient concentration which may be a source of heterogeneity in microbial community structure. In the present study, we investigated the effects of synthetic urine on soil microbial community structure, using physiological (community level physiological profiling, CLPP), biochemical (phospholipid fatty acid analysis, PLFA) and molecular (denaturing gradient gel electrophoresis, DGGE) fingerprinting methods. PLFA data suggested that synthetic urine treatment had no significant effect on total microbial (total PLFA), total bacterial or fungal biomass; however, significant changes in microbial community structure were observed with both PLFA and DGGE data. PLFA data suggested that synthetic urine induced a shift towards communities with higher concentrations of branched fatty acids. DGGE banding patterns derived from control and treated soils differed, due to a higher proportion of DNA sequences migrating only to the upper regions of the gel in synthetic urine-treated samples. The shifts in community structure measured by PLFA and DGGE were significantly correlated with one another, suggesting that both datasets reflected the same changes in microbial communities. Synthetic urine treatment preferentially stimulated the use of rhizosphere-C in sole-carbon-source utilisation profiles. The changes caused by synthetic urine addition accounted for only 10-15% of the total variability in community structure, suggesting that overall microbial community structure was reasonably stable and that changes were confined to a small proportion of the communities.

Animals↗

PubMed1999

Chemical and sensory changes associated with microbial flora of Mediterranean boque (Boops boops) stored aerobically at 0, 3, 7, and 10 degreesC.

The development of a microbial population and changes in the physicochemical and sensorial characteristics of Mediterranean boque (Boops boops), called gopa in Greece, stored aerobically at 0, 3, 7, and 10 degreesC were studied. Pseudomonads and Shewanella putrefaciens were the dominant bacteria at the end of the storage period, regardless of the temperature tested. Enterobacteria and Brochothrix thermosphacta also grew, but their population density was always 2 to 3 log10 CFU g-1 less than that of pseudomonads. The concentration of potential indicators of spoilage, glucose and lactic acid, decreased while that of the alpha-amino groups increased during storage. The concentrations of these carbon sources also decreased on sterile fish blocks inoculated with strains isolated from fish microbial flora. The organic acid profile of sterile fish blocks inoculated with the above-mentioned bacteria and that of naturally spoiled fish differed significantly. An excellent correlation (r = -0.96) between log10 counts of S. putrefaciens or Pseudomonas bacteria with freshness was observed in this study.

Aerobiosis↗

PubMed1999

Cell surface analysis techniques: What do cell preparation protocols do to cell surface properties?

Cell surface analysis often requires manipulation of cells prior to examination. The most commonly employed procedures are centrifugation at different speeds, changes of media during washing or final resuspension, desiccation (either air drying for contact angle measurements or freeze-drying for sensitive spectroscopic analysis, such as X-ray photoelectron spectroscopy), and contact with hydrocarbon (hydrophobicity assays). The effects of these procedures on electrophoretic mobility, adhesion to solid substrata, affinity to a number of Sepharose columns, structural integrity, and cell viability were systematically investigated for a range of model organisms, including carbon- and nitrogen-limited Psychrobacter sp. strain SW8 (glycocalyx-bearing cells), Escherichia coli (gram-negative cells without a glycocalyx), and Staphylococcus epidermidis (gram-positive cells without a glycocalyx). All of the cell manipulation procedures severely modified the physicochemical properties of cells, but with each procedure some organisms were more susceptible than others. Considerable disruption of cell surfaces occurred when organisms were placed in contact with a hydrocarbon (hexadecane). The majority of cells became nonculturable after air drying and freeze-drying. Centrifugation at a high speed (15,000 x g) modified many cell surface parameters significantly, although cell viability was considerably affected only in E. coli. The type of washing or resuspension medium had a strong influence on the values of cell surface parameters, particularly when high-salt solutions were compared with low-salt buffers. The values for parameters obtained with different methods that allegedly measure similar cell surface properties did not correlate for most cells. These results demonstrate that the methods used to prepare cells for cell surface analysis need to be critically investigated for each microorganism so that the final results obtained reflect the nature of the in situ microbial cell surface as closely as possible. There is an urgent need for new, reliable, nondestructive, minimally manipulative cell surface analysis techniques that can be used in situ.

Bacterial Adhesion↗

PubMed2004

[Granularity distribution of airborne microbes in summer in Beijing].

A study on granularity distribution of airborne microbes was conducted in details in summer, and the fluctuation regular was analyzed in Beijing. Results show that the distribution characteristics which are not changed with the different functional regions and periods are very different among airborne bacteria, fungi and actinomycete. Airborne bacteria appear skew distribution, the particles larger than 2.0 microm account for 80.0% of the total while smaller than 1.0 microm contribute 9.0% approximately. Airborne fungi are recorded with normal logarithm distribution, the particles between 1.0 microm and 6.0 microm account for 70.0% while smaller than 1.0 microm contribute 5.0% approximately. The distribution of airborne actinomycete are completely opposite to fungi, the particles larger than 8.2 microm and smaller than 1.0 microm account for 60.0% while between 3.0 microm and 6.0 microm contribute 10.0% approximately. Moreover, the granularity distribution of dominant fungi is consistent in different functional regions. But Cladosporium, Penicillium and Aspergillus are most collected in F3, F4 and F5 grades (1.0-6.0 microm) while Alternaria and nonsporing most in former four grades (>2.0 microm) of FA-I sampler, contributing 85.0%, 85.0%, 85.0%, 90.0% and 75.0% of the total respectively. The granularity of former presents normal logarithm distribution and latter skew distribution. In the past ten years, it is no change on the trend of microbial granularity distribution in Beijing, but the peak value declines from 3.0-6.0 microm to 2.0-3.0 microm.

Air Microbiology↗

PubMed1989

[Bacterial contamination in corneal preservation: pathogens and their origin].

We compared the results of microbiological cultures of conjunctival swabs and organ culture samples of human corneoscleral tissue and found bacterial contimination of the conjunctiva in 54% of all eyes investigated post mortem. Donor age or time after death up to 60 h showed no influence on the rate of microbial growth. The bacterial flora in the conjunctiva was not responsible for microbial growth in the organ cultures, and none of the bacteria found in the cultures could be related to the conjunctival flora. A sterile conjunctival swab does not mean that the organ culture is sterile.

Bacteria↗

PubMed2004

A microbial consortium isolated from a crude oil sample that uses asphaltenes as a carbon and energy source.

A microbial consortium capable of mineralizing asphaltenes was obtained from the Maya crude oil. The enrichment system was built with a glass column reactor containing mineral medium supplied with asphaltenes as energy and carbon source. The consortium growth was evaluated in Casoy agar during 40 weeks. The steady-state phase of the enriched bacterial community was observed after 10 weeks when the culture reach 10(5) to 10(6) CFU ml(-1). The isolates belong to bacterial genus reported for degradation of other hydrocarbons and they were identified as Corynebacterium sp., Bacillus sp., Brevibacillus sp. and Staphylococcus sp. The bacterial consortium growth was evaluated by a viable counts during 14 days exposed to different aeration, temperature, salinity, and pH conditions. The ability of the consortium to mineralize asphaltenes was evaluated using the method of ISO 9439 in glass column reactors of 20 x 3.2 cm during 13 days. Temperatures of 55 degrees C and salinity of 1.8% were growth limiting. The respiration of the microbial consortium using asphaltenes as a sole carbon source (800 micromoles CO2 in 13 days) was significantly higher than those of the samples containing only the microbial consortium (200 micromoles CO2) or only asphaltenes (300 micromoles CO2). These results indicated the existence of asphaltenes-degradating microbes in the crude oil and confirmed that the consortium could mineralize asphaltenes in conditions of room temperature, salinity of 100 ppm, aeration of 1 l min(-1) and pH of 7.4.

Bacillus↗