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PubMedDate not supplied

Can salivary composition and high flow rate explain the low caries rate in children with familial dysautonomia?

PURPOSE: Extremely low caries rate and increased major salivary gland flow rare have been previously reported in children with familial dysautonomia (FD). The purpose of this study was to explore the possibility that, in addition to increased salivary flow, children with FD have alterations in their salivary components, which may suggest an explanauon to their low caries rate. METHODS: Whole unstimulated and stimulated saliva samples were collected from 13 children with FD who were found to be caries free, and from 28 age- and ethnic-matched healthy children, 15 caries-free children and 13 caries-affected children. The electrolyte and protein content of the unstimulated saliva and the microbial count and buffering capacity of the stimulated saliva were determined. RESULTS: Children with FD had the highest salivary flow rate and the lowest levels of mutans streptococci and lactobacilli, as well as the lowest concentration of chloride, magnesium, total protein and IgA. Healthy caries-affected children displayed the highest mutans streptococci and lactobacilli levels and lysozyme concentration, concomitantly with the lowest potassium and calcium concentrations. CONCLUSIONS: The results of this investigation suggest that the caries-free state in FD may be associated with high salivary flow rate, while in healthy children, low caries rate may be associated with high salivary calcium concentration.

Adolescent↗
PubMed2006

Evaluation of the hygienic quality and associated public health hazards of raw milk marketed by smallholder dairy producers in the Dar es Salaam region, Tanzania.

A cross-sectional study was conducted to determine three parameters of the quality of the raw milk marketed by milk selling points (MSPs) in Dar es Salaam region. Total bacterial count (TBC) was used as an indicator of the microbial quality of the milk; antimicrobial residues were determined; and the California mastitis test (CMT) was used to screen for milk somatic cells as an indication of the mastitis level in the cows that provided the milk. Moreover, a water sample at each MSP was taken for bacteriological culturing. Finally, a questionnaire survey was conducted with the milk sellers at the MSPs to identify risk factors for poor milk hygiene. A total of 128 milk samples and corresponding water samples were collected from randomly selected milk selling points in Dar es Salaam region. The mean TBC was (8.2 +/- 1.9) x 10(6) cfu/ml, and major bacterial isolates from the milk samples were Escherichia coli (6.3%), Bacillus cereus (6.3%), Staphylococcus aureus (6.3%) and Streptococcus agalactiae (6.3%), Enterobacter aerogenes (5.6%) and Enterococcus faecalis (4.7%). In most cases, the organisms identified in milk corresponded to those isolated from the corresponding water samples. Of milk samples, 79.0% were positive to the CMT and 7.0% were positive for antimicrobial residues. TBC was normalized by log-transformation, and the possible predictors of TBC were identified by fitting two linear regression models. In a random effect model, water microbial quality, frequency of cleaning the milk containers, frequency of milk supply, milk storage time and the type of containers, and mixing of fresh and previous milk were significantly (p < 0.05) associated with the mean log TBC. In a fixed effect model, in addition to these indicators, water shortage, water source and the refrigerator condition were significantly (p < or = 0.01) associated with log TBC. It was concluded that the milk sold in Dar es Salaam region is of poor quality and is of public health significance.

Animals↗
PubMed2003

The efficacy of a toothbrush disinfectant spray--an in vitro study.

OBJECTIVES: Toothbrushes are contaminated by micro-organisms which may be sources of infection, re-infection or cross infection. The object of this research is to test the efficacy of a proprietary toothbrush spray disinfectant (Brushtox) against specific test bacteria and fungi and to consider its potential. METHODS: Three bacteria and two fungi representing a broad microbial spectrum with relevance to oral bacteria were used in four laboratory tests including an in vitro toothbrush disinfection test. RESULTS: Brushtox proved to be almost 100% effective in three tests and showed significant inhibitory action in the standard agar diffusion test. CONCLUSION: Brushtox is an effective disinfectant agent for bacteria and fungi on toothbrushes. The solution may be valuable in the control of a wide variety of oral infections and secondary infections, especially in frail or debilitated individuals or those on immuno-suppressive therapy, and also in healthy individuals.

Aerosols↗
PubMed2005

Vibrio splendidus biotype 1 as a cause of mortalities in hatchery-reared larval turbot, Scophthalmus maximus (L.).

AIMS: To characterize bacteria associated with turbot larvae feeding on Artemia and identify pathogens causing mortalities in larvae. METHODS AND RESULTS: To identify bacteria associated with mortalities in larval turbot rearing, bacteria were isolated from homogenates of Artemia or from several batches of well-performing or poorly performing turbot larvae. Samples were plated onto marine agar and were characterized using biochemical tests and BIOLOG GN plates. Total culturable aerobic bacteria ranged from 1.9 x 10(5) to 1.8 x 10(6) CFU per larva and >96% of bacteria identified were vibrios. Almost all bacteria were haemolytic and clustered into two phenons represented by Vibrio alginolyticus and Vibrio splendidus. The bacterial flora of Artemia was almost entirely V. alginolyticus, whereas V. splendidus biotype 1 dominated the larval turbot gut flora (69/115 isolates in seven experiments) and formed four different groups based on BIOLOG GN reactions. Of 16 isolates tested for virulence towards turbot larvae, four of the 11 V. splendidus biotype 1 isolates were lethal and all belonged to the same group of V. splendidus biotype 1 isolates. CONCLUSIONS: In a commercial turbot hatchery, the microbial flora of the larval gut was dominated by V. splendidus biotype 1. Four of the 11 V. splendidus biotype 1 isolates caused mortalities in larval turbot and all belonged to one group of the biotype 1 strains identified. SIGNIFICANCE AND IMPACT OF THE STUDY: Identification of four isolates of V. splendidus that are pathogenic for turbot larvae from three separate batches of larval turbot will allow these to be compared with avirulent isolates to define how V. splendidus causes mortalities in larval turbot.

Animals↗
PubMed1998

Specific inhibition of Photobacterium phosphoreum extends the shelf life of modified-atmosphere-packed cod fillets.

Inhibition of the specific spoilage organism, Photobacterium phosphoreum, was studied in model substrates and in modified-atmosphere-packed cod fillets. The objective was to determine how inhibition of this organism influenced spoilage. The spoilage reactions limiting shelf life were studied rather than the development of a new product. In naturally contaminated modified-atmosphere-packed cod fillets, 500 ppm Na2CaEDTA reduced the growth rate of P. phosphoreum by 40% and shelf life was increased proportionally by 40%, from 15 to 17 days to 21 to 23 days at 0 degree C. In aerobically stored cod fillets other microorganisms were responsible for spoilage and Na2CaEDTA had no effect on shelf life. The extension of the shelf life of modified-atmosphere-packed cod therefore was a result of the reduced growth of P. phosphoreum and no other microbial or nonmicrobial spoilage reactions limited shelf life. These results confirmed P. phosphoreum as the specific spoilage organism in modified-atmosphere-packed cod and showed the organism to have an extensive spoilage domain. Consequently, any preservation procedure able to reduce growth of P. phosphoreum is likely to extend shelf life of packed cod. However, the effect of different inhibitory compounds in model systems as well as results from packed cod indicated the need to include product studies in the screening of antimicrobials and in the development of preservation procedures.

Aerobiosis↗
PubMed2001

Microstructural effects on microbial survival: phase-separating dextran solutions.

Evolving microstructure in a model dextran solution is shown to exert a major influence on the survival of Escherichia coli K-12 frag 1 and Salmonella typhimurium LT2. The microstructure results from microscopic phase separation, which develops over several hours resulting in hardening of the solution into a glassy state. The microstructure is characterized by an array of physical methods including image analysis, electron spin resonance and bulk rheology, and it is shown that bacterial survival depends on the formation of microscopic. water-rich domains and not primarily on bulk water activity or hardness.

Colony Count, Microbial↗
PubMed1998

[Model study of ozone microbial decontamination effectiveness of space station environment].

Modeling experiments were performed to evaluate bactericide and fungicide effects of small ozone concentrations (0.3 mg/l of water and 47 mg/m3 of air) that can be generated onboard spacecraft following one hour after treatment. Over the period of treatment, reduction in aquatic microorganisms made up, depending on biotest in use, hundred and more times; concentration of atmospheric microorganisms showed a 5- to 10-fold reduction. The demonstrated effectiveness of ozone shows that it may advantage sterilization and cleaning from microorganisms a number of life support systems aboard manned space vehicles and stations.

Bacteria↗
PubMed2000

A flow cytometry method for rapid detection and enumeration of total bacteria in milk.

Application of flow cytometry (FCM) to microbial analysis of milk is hampered by the presence of milk proteins and lipid particles. Here we report on the development of a rapid (</=1-h) FCM assay based on enzymatic clearing of milk to determine total bacteria in milk. When bacteria were added to ultra-heat-treated milk, a good correlation (r >/= 0.98) between the FCM assay and the more conventional methods of plating and direct microscopic counting was achieved. Raw milk data showed a significant correlation (P < 0.01) and a good agreement (r = 0.91) between FCM and standard plate count methods. The detection limit of the FCM assay was </=10(4) bacteria ml of milk(-1). This limit is below the level of detection required to satisfy legislation in many countries and states.

Animals↗
PubMed2006

Unexpected diversity of bacteria capable of carbon monoxide oxidation in a coastal marine environment, and contribution of the Roseobacter-associated clade to total CO oxidation.

The species diversity, phylogenetic affiliations, and physiological activity rates of carbon monoxide-oxidizing microorganisms were investigated, using new isolates from surface waters collected from the coast of New England and type strains from established collections. A direct isolation method allowed the simultaneous recovery of organisms with different growth rates and nutritional requirements and the identification of marine microorganisms that oxidize CO at an environmentally relevant concentration (42 nM CO). Isolates that oxidized CO at environmentally relevant rates (>4.5x10(-11) nmol CO oxidized cell-1 h-1) were taxonomically diverse, with representatives in the alpha and gamma subclasses of the Proteobacteria and the phylum Bacteroidetes, and represent a hitherto unreported metabolic function for several diverse microbial types. Isolates and type strains having the greatest specific rates of CO metabolism (1.1x10(-10) to 2.3x10(-10) nmol CO oxidized cell-1 h-1) belonged to the Roseobacter-associated clade (RAC) of the alpha subclass of the Proteobacteria. By using triple-labeled slide preparations, differential counts of active CO-oxidizing RAC cells, total RAC cells, and total bacterial cell counts in environmental samples were obtained. RAC organisms were a major component of total cell numbers (36%). Based on the density of active CO-oxidizing RAC cells in natural samples and RAC-specific metabolic activities determined for pure cultures, active CO-oxidizing RAC cells may contribute up to 15% of the total CO oxidation occurring in coastal waters.

Carbon Monoxide↗
PubMed2006

Bacteraemia in patients with hidradenitis suppurativa undergoing carbon dioxide laser surgery: detection and quantification of bacteria by lysis-filtration.

BACKGROUND: Hidradenitis suppurativa (HS) is a cicatrising and persistent disease of apocrine gland-bearing areas in adults. The severity of this condition varies from a few suppurating lesions to widespread, disabling disease. The aetiology is obscure, but suggested contributory factors include a genetic predisposition, comedones occluding the pilosebaceous apparatus, bacterial infections, and hormonal factors. Treatment consists mainly of surgery, while medical therapies serve principally as adjunct therapy. OBJECTIVES: The aim of the study was to determine the number and type of bacteria circulating in the bloodstream in patients with HS undergoing surgical treatment with a carbon dioxide laser stripping-secondary intention technique. METHODS: Twenty-one patients (20 females and 1 male, mean age 36, range 20-55 years) were included in the study. One blood sample (8.3 ml) was taken before surgery, one during the operation and the last one 10 min after surgery. Five healthy persons (all females, mean age 36, range 23-48 years) not undergoing any operation were used as the controls. The blood was cultured by a lysis-filtration technique which had been shown to be very sensitive. Since the filter catches the microorganisms and colonies are formed during culturing, the number of bacteria in the samples is easily determined. RESULTS: In 6 patients, all samples were negative, which indicates that the method of surgery itself caused no spread of bacteria from the lesions. Bacterial growth in the first blood sample was found in 9 patients, from the second sample in 10 and from the third one in 6. In 1 patient, bacteria were detected in three samples. At least 12 bacterial species were identified. The dominating bacteria were coagulase-negative staphylococci of which most were subtyped as Staphylococcus warneri. Among the anaerobic microorganisms, Propionibacterium acnes and P.granulosum were the most frequently isolated bacteria. The bacterial findings in the blood samples accord well with the results from a previous study in which cultures were taken from the deep parts of the HS lesions. In the 5 controls, no microbial growth was detected. CONCLUSION: The carbon dioxide laser stripping technique caused no additional spread of bacteria into the bloodstream. The evaluation of cultures containing microorganisms from normal skin flora is controversial. Since the bacteria encountered in this study are in close agreement with the findings in cultures from the deeper parts of HS lesions they seem to be relevant. The growth of bacteria in the first blood sample taken before surgery may indicate that some of these patients have bacteria continuously circulating in their blood.

Adult↗
PubMed2002

Control of natural microbial flora and Listeria monocytogenes in vacuum-packaged trout at 4 and 10 degrees C using irradiation.

The effect of gamma irradiation on the natural microflora of whole salted vacuum-packaged trout at 4 and 10 degrees C was studied. In addition, the effectiveness of gamma irradiation in controlling Listeria monocytogenes inoculated into trout was investigated. Irradiation at doses of 0.5 and 2 kGy affected populations of bacteria, namely, Pseudomonas spp., Brochothrix thermosfacta, lactic acid bacteria, H2S-producing bacteria typical of Shewanella putrefaciens, and Enterobacteriaceae, at both 4 and 10 degrees C. This effect was more pronounced at the higher dose (2 kGy) and the lower temperature (4 degrees C). Pseudomonads, H2S-producing bacteria typical of S. putrefaciens, and Enterobacteriaceae showed higher sensitivity to gamma irradiation than did the rest of the microbial species. Sensory evaluation did not show a good correlation with bacterial populations. On the basis of sensory odor scores, a shelf life of 28 days (2 kGy, 4 degrees C) was obtained for salted vacuum-packaged freshwater trout, compared with a shelf life of 7 days for the unirradiated sample. Under the same conditions, the growth of L. monocytogenes inoculated into the samples was suppressed by 2 log cycles after irradiation (2 kGy) and storage for up to 18 days at 4 degrees C.

Animals↗
PubMed2004

Application of elements of microbiological risk assessment in the food industry via a tiered approach.

Food safety control is a matter for concern for all parts of the food supply chain, including governments that develop food safety policy, food industries that must control potential hazards, and consumers who need to keep to the intended use of the food. In the future, food safety policy may be set using the framework of risk analysis, part of which is the development of (inter)national microbiological risk assessment (MRA) studies. MRA studies increase our understanding of the impact of risk management interventions and of the relationships among subsequent parts of food supply chains with regard to the safety of the food when it reaches the consumer. Application of aspects of MRA in the development of new food concepts has potential benefits for the food industry. A tiered approach to applying MRA can best realize these benefits. The tiered MRA approach involves calculation of microbial fate for a product and process design on the basis of experimental data (e.g., monitoring data on prevalence) and predictive microbiological models. Calculations on new product formulations and novel processing technologies provide improved understanding of microbial fate beyond currently known boundaries, which enables identification of new opportunities in process design. The outcome of the tiered approach focuses on developing benchmarks of potential consumer exposure to hazards associated with new products by comparison with exposure associated with products that are already on the market and have a safe history of use. The tiered prototype is a tool to be used by experienced microbiologists as a basis for advice to product developers and can help to make safety assurance for new food concepts transparent to food inspection services.

Bacteria↗
PubMedDate not supplied

Behavior of Listeria monocytogenes in pH-modified chicken salad during refrigerated storage.

The growth and inactivation kinetics of L. monocytogenes were evaluated at pH 4.0, 4.6, and 5.2 during storage at 5.0 degrees C, 7.2 degrees C, and 21.1 degrees C (41 degrees F, 45 degrees F, and 70 degrees F). Using commercially produced pasteurized chicken salad, the authors adjusted the pH levels with acetic acid or sodium acetate. Samples of 25 g each of the pH-modified salad were inoculated to approximately 1 x 10(6) cells per gram with a three-strain mixture of L. monocytogenes and stored for up to 119 days. Samples were enumerated for L. monocytogenes according to the Food and Drug Administration-modified most-probable-number (MPN) procedure, and log MPN was plotted against time. Inactivation was seen at all pH levels and at all temperatures. At 21.1 degrees C, a 6-log reduction was seen after 14 days at pH 4.0, after 52 days at pH 4.6, and after 38 days at pH 5.2. Inactivation at 21.1 degrees C began within hours or days at pH 4.0, and after a lag phase of 10 to 12 days at pH 4.6 and 5.2. Inactivation was slower in cold-storage temperatures. At 7.2 degrees C, a microbial reduction of 1.1 log (pH 5.2) and > 3 log (pH 4.0 and 4.6) was observed at 119 days. At 5 degrees C, a 7.5-log reduction was observed at 24 days at pH 4.0. At pH levels of 4.6 and 5.2, however, only a 4-log reduction was found at 119 days. The data generated in this study may be used to develop predictive models that could specifically address the interactions of pH and storage temperature on the viability of L. monocytogenes in prepared salads.

Acetic Acid↗
PubMed1989

Estimation of microbial densities from dilution count experiments.

Although dilution counts have been widely used in quantitative microbiology, their interpretation has always been widely discussed both in microbiology and in applied statistics. Maximum-likelihood (most-probable-number) methods hae generally been used to estimate densities from dilution experiments. It has not been widely recognized that these methods are intrinsically and statistically biased at the sample sizes used in microbiology. This paper presents an analysis of proposed method for correction of such biases, and the method was found to be robust for moderate deviations from Poisson behavior. For analyses at greater variance with the Poisson assumptions, the use of the Spearman-Karber method is analyzed and shown to yield an estimate of density of lesser bias than that produced by the most-probable-number method. Revised methods of constructing confidence limits proposed by Loyer and Hamilton (M.W. Loyer and M.A. Hamilton, Biometrics 40:907-916, 1984) are also discussed, and charts for the three- and four-decimal dilution series with five tubes per dilution are presented.

Colony Count, Microbial↗
PubMed1990

[Bronchoscopic diagnosis of pneumonia with quantitative microbial count determination].

Micro-organism counts of bronchoalveolar lavage (BAL) and microbrush swabs were obtained from 40 immunocompetent (group A) and 23 immunosuppressed (group B) patients with nosocomial pneumonia, and a control group consisting of 40 patients with noninfectious pulmonary infiltrates. The sensitivity of BAL was high: 77.5% for group A and 85% for group B, while microbrush swabs gave many false-negative results. Microorganism counts were at or above 10(5) cfu/ml in 32 of 44 examinations (bacterial or mycotic pneumonia), but in only one case of the control group. Lower counts were obtained with localized infection and microorganisms difficult to culture (Aspergilla and Legionella). Granulocytosis in the lavage fluid was demonstrated in 38 of 41 patients with bacterial pneumonia and thus proved useful in the differential diagnosis. In 16 of 40 immunocompetent and 13 of 23 immunosuppressed patients with pneumonia the results were therapeutically of importance. Thus, invasive diagnosis is indicated especially in complicated or treatment-resistant nosocomial infections.

Adult↗
PubMed1995

Bacterial peritonitis in continuous ambulatory peritoneal dialysis: effect on dialysis on host defense mechanisms.

We have used an experimental model of continuous ambulatory peritoneal dialysis (CAPD) to investigate the effect of dialysis on host defense mechanisms in the peritoneal cavity. Laboratory rats undergoing regular dialysis were challenged with a single bolus of Staphylococcus epidermidis, Staphylococcus aureus, Candida albicans, and Pseudomonas aeruginosa. Intraperitoneal challenges with all four microbial strains underwent a rapid clearance during the first 4 hours, irrespective of whether the host was undergoing dialysis. Studies using S epidermidis showed that the rapid clearance was not mediated by the diaphragmatic stomata as might have been expected. Dialysis did, however, cause delays over the following 48 hours with all of the pathogens except C albicans. Bacterial clearance over a 10-day period was strain dependant, and microbial persistence was related to adhesion formation around the cannula. Again C albicans was an exception. Our conclusions are that dialysis does not affect the innate defense mechanisms involved in the early clearance of a bolus challenge to the peritoneal cavity but can cause delays in eradicating microorganisms that survive this phase. Because these experiments were carried out using a bolus inoculum, it may be necessary to reevaluate the effect of dialysis on host defenses in the peritoneal cavity under conditions in which the challenge more closely approximates a touch contamination event.

Animals↗
PubMed1993

Effect of treated-sewage contamination upon bacterial energy charge, adenine nucleotides, and DNA content in a sandy aquifer on Cape Cod.

Changes in adenylate energy charge (ECA) and in total adenine nucleotides (A(T) and DNA content (both normalized to the abundance of free-living, groundwater bacteria) in response to carbon loading were determined for a laboratory-grown culture and for a contaminated aquifer. The latter study involved a 3-km-long transect through a contaminant plume resulting from continued on-land discharge of secondary sewage to a shallow, sandy aquifer on Cape Cod, Mass. With the exception of the most contaminated groundwater immediately downgradient from the contaminant source, DNA and adenylate levels correlated strongly with bacterial abundance and decreased exponentially with increasing distance downgradient. ECAS (0.53 to 0.60) and the ratios of ATP to DNA (0.001 to 0.003) were consistently low, suggesting that the unattached bacteria in this groundwater study are metabolically stressed, despite any eutrophication that might have occurred. Elevated ECAS (up to 0.74) were observed in glucose-amended groundwater, confirming that the metabolic state of this microbial community could be altered. In general, per-bacterium DNA and ATP contents were approximately twofold higher in the plume than in surrounding groundwater, although ECA and per-bacterium levels of A(T) differed little in the plume and the surrounding uncontaminated groundwater. However, per-bacterium levels of DNA and A(T) varied six- and threefold, respectively, during a 6-h period of decreasing growth rate for an unidentified pseudomonad isolated from contaminated groundwater and grown in batch culture.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1997

The effect of surface roughness on early in vivo plaque colonization on titanium.

THE STUDY ASSESSES IN VIVO the surface roughness necessary to reduce plaque colonization on titanium after 24 hours. Three groups of 16 titanium disks were assigned to 3 different polishing groups (A, B, and C). The roughness was evaluated with a laser profilometer and the morphology with a scanning electron microscope (SEM). Eight volunteers were enrolled and two stents were applied in the mandibular posterior region of each. Each stent supported 3 disks, one per group. The volunteers suspended oral hygiene for 24 hours, after which the stents were removed; one was processed for evaluation of the adherent biomass and the other for SEM study. On each specimen a global area of 100 x 125 microns was examined with SEM. The area was composed of five 20 x 25 microns randomly selected fields. For each field the density of bacteria and the morphotypes were recorded. The data quoted for the global area are cumulative of those observed in the 20 x 25 microns fields. Group A had a significantly smoother surface than groups B and C. The adherent microbial biomass determination and SEM evaluation revealed that group A contained less bacteria than the roughest group. The bacterial population was composed of cocci in group A, and of cocci and short and long rods in groups B and C. We conclude that a titanium surface with Ra < or = 0.088 microns and Rz < or = 1.027 microns strongly inhibits accumulation and maturation of plaque at the 24-hour time period and that such smoothness can be achieved in transgingival and healing implant components.

Analysis of Variance↗