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PubMedDate not supplied

Periodontal diseases, caries, and microbial composition of the subgingival plaque in children: a longitudinal study.

The present study compares periodontal parameters, caries, and levels of colony forming units (CFU) of bacteria from subgingival plaque of permanent teeth, to those of primary teeth examined 4 years previously. Six children who had periodontitis and 5 who had no periodontitis in primary teeth (groups A and B respectively) were examined. The microbial examination included the number of CFU of the total anaerobic count, Actinobacillus actinomycetemcomitans, Streptococcus mutans and Porphyromonas gingivalis. The differences in CFU values for the permanent teeth between groups A and B were not significant. Group A had significantly higher gingival inflammation values in the permanent teeth than group B. Permanent teeth had significantly higher CFU values of P. gingivalis than the primary teeth. Based on the present limited sample, the number of CFU from bacteria of the subgingival plaque of primary teeth are not an adequate predictor of periodontal disease or caries in the permanent teeth.

Adolescent↗
PubMed1999

Variability of some microbial parameters in relation to the hydrological features of the water column in the Eolian Basin (Southern Tyrrhenian Sea).

During the EOCUMM '94 cruise, 15 stations located in the Eolian Islands area (Southern Tyrrhenian Sea) were sampled to analyse the distributions of the total bacterioplankton densities and the heterotrophic viable bacteria counts on Marine Agar 2216. According to the TS (temperature-salinity) diagrams, obtained by processing the CTD (conductivity-temperature-depth) vertical profiles, the sampled stations were grouped in "hydrological clusters". The bacteriological variables, together with the chlorophyll a and the particulate organic carbon measures obtained during the same cruise were used to compare the stations of the same and different clusters. The results indicated that variabilities of the analysed microbial parameters were not obviously related to the hydrographic features of the sampling stations. This work is an attempt to verify the possibility of using microbial parameters to characterize the structure of the water column.

Analysis of Variance↗
PubMed2005

A field study of the microbiological quality of fresh produce.

The Centers for Disease Control and Prevention has reported that foodborne disease outbreaks associated with fruits and vegetables increased during the past decade. This study was conducted to characterize the routes of microbial contamination in produce and to identify areas of potential contamination from production through postharvest handling. We report here the levels of bacterial indicator organisms and the prevalence of selected pathogens in produce samples collected from the southern United States. A total of 398 produce samples (leafy greens, herbs, and cantaloupe) were collected through production and the packing shed and assayed by enumerative tests for total aerobic bacteria, total coliforms, total Enterococcus, and Escherichia coli. These samples also were analyzed for Salmonella, Listeria monocytogenes, and E. coli O157:H7. Microbiological methods were based on methods recommended by the U.S. Food and Drug Administration. For all leafy greens and herbs, geometric mean indicator levels ranged from 4.5 to 6.2 log CFU/g (aerobic plate count); less than 1 to 4.3 log CFU/g (coliforms and Enterococcus); and less than 1 to 1.5 log CFU/g (E. coli). In many cases, indicator levels remained relatively constant throughout the packing shed, particularly for mustard greens. However, for cilantro and parsley, total coliform levels increased during the packing process. For cantaloupe, microbial levels significantly increased from field through packing, with ranges of 6.4 to 7.0 log CFU/g (aerobic plate count); 2.1 to 4.3 log CFU/g (coliforms); 3.5 to 5.2 log CFU/g (Enterococcus); and less than 1 to 2.5 log CFU/g (E. coli). The prevalence of pathogens for all samples was 0, 0, and 0.7% (3 of 398) for L. monocytogenes, E. coli O157:H7, and Salmonella, respectively. This study demonstrates that each step from production to consumption may affect the microbial load of produce and reinforces government recommendations for ensuring a high-quality product.

Bacteria↗
PubMed2003

The microflora recovered from the outer-surfaces of the Frialit-2 implanto-prosthetic connector.

The aim of the present investigation was to examine the outer-surface microbiota of the prosthetic connector of Frialit-2 implants, and to compare the microbial findings with the peri-implant parameters 2 years after functional loading. In 16 implant-treated patients (55.8 +/- 9.5 years) the outer-surface micro-organisms of the prosthetic connectors were determined in 32 Frialit-2 implants. The functional loading time of the prosthetic suprastructures was 24.1 +/- 13.8 months on average. After removal of the implant-supported restoration, microbial samples were obtained from the outer-surfaces of the Frialit-2 prosthetic connector. The microbial plaque samples were specified on CDC-blood agar as percentages of the total cultivable flora. Actinobacillus actinomycetemcomitans was semiquantitively determined on TSBV-agar in CFU/ml. The microbial plaque samples were dominated by Actinomyces israelii (68.8%), Eubacterium lentum (56.3%) and Veillonella parvula (43.8%) with proportions ranking between 3.9% (V. parvula) and 11.1% (A. israelii). The most frequently detected gram-negative microorganisms were Fusobacterium nucleatum (87.5%), Porphyromonas gingivalis (81.3%), and Peptostreptococcus micros (68.8%) with enhanced proportions for P. gingivalis (11.4%) and P. micros (11.4%). No statistical significant correlation could be established between the microbiota present on the outer-surfaces of the F2-connector and the peri-implant parameters examined. The outer-surface microflora recovered from the implanto-prosthetic-connector of Frialit-2 implants reveals a colonization with gram-positive bacteria and potentially harmful gram-negative micro-organisms that were frequently detected, but present at low levels. After 2 years of restorative loading, the outer-surface microbial colonization is compatible with peri-implant soft tissue health.

Actinomyces↗
PubMedDate not supplied

Identifying the determinants of viable microorganisms in the air and bulk metalworking fluids.

Exposure assessment was conducted for an epidemiologic study of the respiratory effects of exposure to metalworking fluids (MWF). As part of the study, airborne microorganisms were collected with a two-stage microbial impactor, and a sample of the bulk soluble MWF was collected from each machine sump, as well as information about the work environment. These data were then used to develop multivariate statistical models of the determinants bulk MWF and airborne microbial levels. Microbial concentrations in the bulk MWF ranged from 5 x 10(4) to 5 x 10(10) colony-forming units (CFU)/mL, with a geometric mean of 3.4 x 10(7) CFU/mL. The geometric mean airborne microbial level was 182 CFU/m3 (for particles size <8 microm) with a range of 1 to 8,308 CFU/m3. In modeling the determinants of bulk microorganisms, fluid-related factors were the most important characteristics associated with microbial levels, followed by process-related and environmental factors. The final full multivariate model predicted a significant reduction in bulk microbial levels by increasing pH of the fluid and reducing the amount of tramp oil leaking into the fluid. For the airborne microbial models, process-related factors were the major characteristics associated with microbial levels, followed by factors related to worker activities and environmental factors. The final full multivariate model predicted a significant control of airborne microorganisms by increasing worker distance from the machine, reducing the number of machines within 10 feet of the worker, decreasing the bulk microbial levels, and adding machine enclosures. These models can be used to prioritize nonbiocidal interventions to control microbial contamination of the bulk MWF and the air.

Air Microbiology↗
PubMed2003

Evaluation of the antimicrobial efficacy of urinary catheters impregnated with antiseptics in an in vitro urinary tract model.

OBJECTIVES: To evaluate the long-term efficacy of urinary Foley catheters (latex and silicone) impregnated with (1) chlorhexidine and silver sulfadiazine (CXS) and (2) chlorhexidine, silver sulfadiazine, and triclosan (CXST) in inhibiting extra-luminal bacterial adherence and to compare their efficacy with that of silver hydrogel latex (SH) and nitrofurazone-treated silicone (NF) catheters. DESIGN: The antimicrobial spectrum of these catheters was evaluated using a zone of inhibition assay. A novel in vitro urinary tract model was developed to study the potential in vivo efficacy of antimicrobial catheters in preventing extraluminal bacterial colonization. The "meatus" was inoculated daily with Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Enterococcus faecalis, Pseudomonas aerginosa, and Candida albicans. The "bladder" portion of the model was cultured daily to determine bacterial growth. RESULTS: Both CXS and CXST catheters had a broader antimicrobial spectrum than SH and NF catheters. In the in vitro model, CXST latex and silicone catheters exhibited significantly better efficacy (3 to 25days) against uropathogens, compared with CXS (1 to 14 days) and control (0 to 5 days) catheters (P = .01). CXST latex catheters exhibited significantly longer protection against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa, compared with SH catheters (P = .01). CXST silicone catheters resisted colonization with Staphylococcus aureus and Staphylococcus epidermidis for a significantly longer period (23 to 24 days) than did NF catheters (9 to 11 days) (P = .01). CONCLUSION: Catheters impregnated with synergistic combinations of chlorhexidine, silver sulfadiazine, and triclosan exhibited broad-spectrum, long-term resistance against microbial colonization on their outer surfaces.

Anti-Infective Agents, Urinary↗
PubMed2004

Inactivation of Escherichia coli O157:H7 by high-intensity ultrasonication in the presence of salts.

Inactivation of Escherichia coli O157:H7 suspended in salt solutions (Na(2)PO(4), NaCl, NaNO(3), NH(4)Cl, CaCl(2), and AlCl(3)) at concentrations ranging from 0 to 5% (w/v) by high-intensity ultrasound at two different temperature conditions (ice water bath, 40 degrees C water bath) and three ultrasonic intensity levels (9.5, 21.8, 49.2 W/cm(2)) was determined. Increases in sonication treatment time, intensity, and temperature led to increased lethality of E. coli O157:H7. However, cell lethality, as a function of solute concentration, varied depending upon type of salt. CaCl(2), NaCl, NaNO(3), Na(2)PO(4), and NH(4)Cl had little or no effect on survival of E. coli O157:H7 (<1-log reduction) regardless of other treatment conditions at 9.5 W/cm(2). Concentrations of >0.5% of CaCl(2), NaNO(3), Na(2)PO(4), and NH(4)Cl adversely affected survival (1.0- to 1.6-log reduction) with treatment of 21.8 W/cm(2) in an ice bath and showed greater inactivation (1.2-4.0-log reduction) in the 40 degrees C water bath. Treatment of 49.2 W/cm(2) showed the greatest impact regardless of other parameters. In the 40 degrees C water bath, treatment for 10 min at 49.22 W/cm(2) led to total inactivation for cells suspended in 0.5% NH(4)Cl, 1% CaCl(2), 2% NaCl, 5% Na(2)PO(4), and all concentrations of AlCl(3). Complete inactivation also occurred in an ice bath for 5% AlCl(3), which was shown to be the most effective salt. The most efficient treatment combination was in the 40 degrees C water bath for 10 min at 49.2 W/cm(2) with 5% AlCl(3). Inactivation of E. coli O157:H7 is attributed to cavitation-induced shear forces, reaction of cavitation-generated hydrogen peroxide with microbial cell wall constituents and electrostatic interactions of dissociated salts with cell membranes.

Colony Count, Microbial↗
PubMed1997

Growth reduction of Listeria spp. caused by undefined industrial red smear cheese cultures and bacteriocin-producing Brevibacterium lines as evaluated in situ on soft cheese.

The undefined microbial floras derived from the surface of ripe cheese which are used for the ripening of commercial red smear cheeses have a strong impact on the growth of Listeria spp. In some cases, these microbial consortia inhibit Listeria almost completely. From such undefined industrial cheese-ripening floras, linocin M18-producing (lin+) (N. Valdés-Stauber and S. Scherer, Appl. Environ. Microbiol. 60:3809-3814, 1994) and -nonproducing Brevibacterium linens strains were isolated and used as single-strain starter cultures on model red smear cheeses to evaluate their potential inhibitory effects on Listeria strains in situ. On cheeses ripened with lin+ strains, a growth reduction of L. ivanovii and L. monocytogenes of 1 to 2 log units was observed compared to cheeses ripened with lin strains. Linocin M18 activity was detected in cheeses ripened with lin+ strains but was not found in those ripened with lin strains. We suggest that production of linocin M18 contributes to the growth reduction of Listeria observed on model red smear cheeses but is unsufficient to explain the almost complete inhibition of Listeria caused by some undefined microbial floras derived from the surface of ripe cheeses.

Bacteriocins↗
PubMed1994

Role of bile in non-specific defence mechanisms of the gut.

The effect of depriving the intestine of bile for 48 hours was studied to determine any influence on various parameters of innate immunity in the gastrointestinal tract. Groups of rats were prepared by bile duct cannulation (with or without fluid replacement) or bile duct ligation. Normal and sham operated animals were used for comparing the thickness of the mucus layer and the cells contained therein, enumeration of goblet cells, and measurement of villus size. Histological examination indicated that the intestinal tissues of treated and control rats were similar. Though villus size and numbers of goblet cells were unaffected, a significant reduction occurred in the thickness of the mucus blanket in the duodenal regions of rats deprived of bile, and there were significantly lower numbers of mucus associated enterocytes and lymphocytes, suggesting a lower turnover rate of the epithelium. The balance of the bacterial populations in the caecum and intestine was altered by bile deprivation-increased numbers of coliform organisms were found in both regions. The range of factors, including antibodies and other known constituents, present in bile may contribute to the maintenance of tissue integrity and influence the balance in indigenous bacterial populations in the intestine. Disturbance of the host's biliary system and concomitant effects on the microbial flora may weaken the overall processes of defence in the intestine.

Animals↗
PubMed2006

Sampling strategy for intraoral detection of periodontal pathogens before and following periodontal therapy.

BACKGROUND: The aim of this study was to identify a sampling strategy with high probability for detecting oral colonization by Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Eikenella corrodens, Tannerella forsythensis, Prevotella intermedia, Prevotella nigrescens, and Treponema denticola before and following mechanical periodontal therapy. METHODS: Samples were taken from the following intraoral sites in 35 patients with untreated chronic periodontitis before and 1.5, 3, and 6 months after non-surgical periodontal therapy: supra- and subgingival plaque from the deepest pockets in each sextant; pooled supra- and subgingival plaque from another six randomly selected, less affected teeth; mucosal swab samples from the tongue, tonsils, throat, and buccal mucosa; and stimulated and unstimulated saliva. Microbial species were identified by polymerase chain reaction (PCR). RESULTS: Of the sampling of all assessed sites, the highest probability for simultaneously detecting the tested pathogens was found in respect to the combination of supra- and subgingival plaque samples taken from the most affected tooth in each sextant in untreated patients (probability: 83% to 95% for the assessed bacteria). These results were consistently observed throughout the study period. CONCLUSIONS: For determining the intraoral carrier state of patients with periodontitis, a combined sample of supra- and subgingival plaque taken from the deepest periodontal pocket in each sextant may yield the most reliable result. This sampling strategy may be used in routine microbial testing and clinical research.

Bacteria, Anaerobic↗
PubMed2001

Destruction of Escherichia coli O157:H7 and Salmonella enteritidis in cow manure composting.

Application of cow manure and composted manure in agricultural practice could potentially cause contamination of foodstuffs with pathogenic bacteria such as Salmonella Enteritidis and Escherichia coli O157:H7. In this study, rifampicin-resistant (RifR) E. coli O157:H7 and Salmonella Enteritidis at a level of 7 log CFU/g of raw compost feed were used to determine the effect of a bench-scale composting system on their survival. RifR E. coli O157:H7 was not detected after 72 h of composting at 45 degrees C, and RifR Salmonella Enteritidis was not detected after 48 h. The use of selective media for enrichment failed to recover in the composting samples held at 45 degrees C for 96 h. However, the pathogens showed no change in bacterial numbers when the composting system was held at room temperature. Thus, properly composted manure can be safely used in food crop production while minimizing the likelihood of microbial contamination.

Animals↗
PubMed1999

Prospective randomized investigation for evaluation of postoperative changes in the microbial climate of paranasal mucosa by the use of different dissoluting techniques during postoperative care.

Endonasal dissolution by the use of NaCl-solution is a common postoperative treatment of the nasal mucosa after endonasal surgery. These procedure involve for example endonasal shower and sterilized solutions. The contamination of nasal shower in case of unprofessional cleaning after treatment was an argument against this technique in earlier discussions. The danger of such an infection should be avoided by the use of sterilized solution. Therefore the dependence of nasal microbial climate on different nasal dissoluting techniques was investigated by the use of such named endonasal shower (Siemens und Co, Bad Ems, Germany) in comparison with sterilized solution (Rhinomer, Zyma SA, Nyon, France). Microbial cultures were investigated of 80 patients after endonasal surgery (53 m, 27 f; 31 +/- 21 age). Surgery was done for the treatment of chronic polypous sinusitis. Pre-, intra- and postoperative samples were taken in 640 cases to proceed microbial cultures. Material was transferred with the use of a Port-A-Cul-transport medium and preparation of the microbial cultures was done during the first four hours. As a result 895 bacterial clones were cultivated. These consisted of 87% aerob and 13% anaerob bacteria. Staphylococcus aureus (39%) and members of the family of Enterobactericae (30%) were the most common microbes. There was neither an evidence for postoperative microbes on the nasal mucosa nor a correlation between the dissoluting technique and the postoperative outcome. The use of sterilized solutions for the postoperative care of endonasal mucosa does not cause an additional worthful effect on neither the postoperative microbial climate nor the outcome in comparison to endonasal shower.

Adolescent↗
PubMedDate not supplied

A rapid method for screening for Salmonella typhimurium in a chicken cecal microbial consortium using gene amplification.

A rapid sample processing method has been developed to detect low numbers of Salmonella typhimurium in a chicken cecal microbial consortium. Using phoP-specific primers under stringent amplification conditions and gene probe analysis, fewer than 100 colony-forming units (CFUs) were detectable when pure cultures were employed. When the polymerase chain reaction assay was run on cecal contents from birds infected with S. typhimurium, only positive cecal samples containing as few as 700 CFUs reacted to the assay, and the negative bird samples reacted only when the samples were spiked with S. typhimurium cells. The method employed for sample processing is simple and provides a sensitive means of detecting S. typhimurium-specific sequences in trace amounts in the presence of mixed chicken cecal microbial populations.

Animals↗
PubMed2004

Molecular weight of chitosan influences antimicrobial activity in oil-in-water emulsions.

The objective of this study was to evaluate the antimicrobial efficiency of chitosans in oil-in-water emulsions. Model emulsions were prepared with 20% corn oil, 1.5% Tween 20, 1.5% Trypticase soy broth, 0.58% acetic acid, and chitosan polysaccharide or chitosan oligosaccharide in concentrations of 0, 0.1, 0.2, 0.5, and 0.7%. A control containing HCl was included to determine the role of acetic acid in the overall antibacterial activity. The pH of samples and controls was adjusted to 4.5. Emulsions were inoculated with Listeria monocytogenes (strains Scott A and 310) or Salmonella Typhimurium DT104 (strains 2486 and 2576) at a level of 10(7) CFU/ml. Inoculated emulsions were incubated at 10 and 25 degrees C for 4 days and analyzed for bacterial count every 24 h. Both tested Salmonella strains were more susceptible to acetic acid than Listeria. However, L. monocytogenes was more affected by chitosan than either Salmonella strain. During the storage at 25 degrees C, initial inoculum in the emulsions with 0.58% acetic acid and 0.1% chitosan polysaccharide was reduced to below the detection limits after 24, 48, 72, or 96 h for L. monocytogenes 310, Salmonella Typhimurium DT104 2576, Salmonella Typhimurium DT104 2486, or L. monocytogenes Scott A, respectively. Chitosan oligosaccharide was less effective against all tested bacteria and showed a concentration-dependent effect. The antimicrobial efficacy of chitosan was reduced at 10 degrees C, and reduction of microbial loads was delayed for approximately 24 h compared with 25 degrees C. Results suggest that addition of 0.1% chitosan polysaccharide would be sufficient to ensure the microbial safety of oil-in-water emulsions regardless of storage temperature.

Anti-Bacterial Agents↗
PubMed1995

Periodontopathogens in elderly Chinese with different periodontal disease experience.

If an etiological relationship exists between destructive periodontal disease and putative periodontopathogens, they would be expected to have a very low prevalence in periodontally healthy elderly persons. To test this hypothesis, 2 subgroups of elderly, rural Chinese (a periodontally "best" and a "worst" group, each comprising 15 persons) were identified in 1990 from a cohort aged 55-69 years, examined in 1984. Assessment of changes in periodontal status over the 6-year period were possible by comparing detailed clinical recordings performed by the same examinator. Subgingival microbial samples were taken at the mesial aspects of an upper central incisor and a lower canine and examined for the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia group, Prevotella melaninogenica group, Capnocytophaga, Selenomonas, Campylobacter rectus as well as predominant Streptococcus and Actinomyces species. During the 6 years prior to microbiological sampling, persons in the "best" group had lost an average of 1.21 +/- 0.48 mm attachment, while persons in the "worst" group had lost an average of 1.60 +/- 0.94 mm. The latter group had lost 53.3 teeth, predominantly for periodontal reasons, in contrast to 1.8 teeth lost in the "best" group. "Best" persons did not differ from "worst" persons with respect to the occurrence of the putative periopathogens, total viable count, and total streptococcal and Actinomyces recovery. Similarly, sites which had experienced an attachment loss > or = 2 mm during the 6-year period did not differ microbiologically from sites with less attachment loss. It is concluded that subgingival microbial characterization does not allow for a distinction between elderly individuals with markedly different periodontal disease experiences.

Actinomyces↗
PubMedDate not supplied

[Effects of medium with elevated partial pressure of argon and nitrogen on morphology of Escherichia coli colonies].

The purpose was to study morphological specifics of microbial colonies cultivated in argon-containing gas medium. Investigated were computerized images of the colonies of museum strains Escherichia coil K-12. It was found that combination of elevated argon pressure (1 ata) and nitrogen pressure (1.8 ata) increased the maximal density of microbial colonies and decreased the colony size as compared with cultivation in argon only.

Argon↗