Status of bacterial colonization, Toll-like receptor expression and nuclear factor-kappa B activation in normal and diseased human livers.

Epidemiological data on bacterial translocation (BT), colonization and inflammation in normal human livers is lacking. In this study we investigated the status of bacterial colonization and inflammation in the normal, cirrhotic primary biliary cirrhosis (PBC), and nonalcoholic steatohepatitis (NASH) human liver tissues. Comparatively normal livers showed increased bacterial colonization than PBC and NASH. We analyzed mRNA levels of Toll-like receptors (TLR) 2 and TLR4, and protein levels of TLR4. Phosphorylated IKKα (pIKKα) protein estimation served as a marker for nuclear factor-kappa B (NF-κB) activation. In spite of the increased bacterial colonization in normal liver tissues, lower levels of TLR2/4 mRNA and TLR4 and pIKKα proteins were found compared to PBC and NASH indicating the maintenance of suppressed inflammation and immune tolerance in normal livers. To our knowledge, this is the first clinical evidence showing suppressed inflammation despite bacterial colonization in normal human livers thus maintaining liver immune homeostasis.

Triclosan-induced modification of unsaturated fatty acid metabolism and growth in Pseudomonas aeruginosa PAO1.

Triclosan is a broad-spectrum antimicrobial agent having low toxicity which facilitates its incorporation into numerous personal and health care products. Although triclosan acts against a wide range of gram-positive and gram-negative bacteria by affecting fatty acid biosynthesis, it is ineffective against the opportunistic pathogen Pseudomonas aeruginosa. Wild-type strain P. aeruginosa PAO1 was used as a model system to determine the effects of triclosan on fatty acid metabolism in resistant microorganisms. This was accomplished by cultivating P. aeruginosa PAO1 cultures in the presence of different concentrations of triclosan, monitoring growth rates turbidimetrically, and harvesting in stationary phase. Readily extractable lipids (RELs) were obtained from freeze-dried cells after washing and analyzed using gas chromatography coupled with mass spectrometry. Resultant data demonstrated that triclosan caused dose-dependent increases in the amounts of trans-C(16:1) and trans-C(18:1) fatty acids, with concomitant decreases in their respective cyclopropyl analogs. Triclosan did not affect the relative concentrations of saturated, cis unsaturated, or the overall ratios of combined C(16) to C(18) fatty acid species. The readily extractable lipid fractions contained triclosan proportional to triclosan concentrations in the growth media. The presence or absence of triclosan in either liquid or solid media did not affect the antimicrobial susceptibilities of P. aeruginosa PAO1 to a battery of unrelated antimicrobials. Triclosan decreased growth rate in a dose-dependent manner at soluble concentrations. Incorporation of triclosan into the REL fraction was accompanied by increased levels of trans unsaturated fatty acids, decreased levels of cyclopropyl fatty acids, and decrease in growth rate. These alterations may contribute to triclosan resistance in P. aeruginosa PAO1.

Evaluation of the microbial flora found in woodwind and brass instruments and their potential to transmit diseases.

Previous studies of dental devices (toothbrushes, dentures, and protective athletic mouthguards) have demonstrated microbial contamination of these devices and possible transmission of infectious diseases to the users. Since woodwind and brass instruments come into intimate contact with the musician's oral cavity and often are passed from student to student without sanitization, the question arises as to whether these instruments are contaminated and can transmit microbial diseases. The purpose of this study was to determine if woodwind and brass instruments and/or their cases harbor opportunistic, pathogenic, or allergenic microorganisms that can be transmitted to the musician. The internal components of woodwind and brass instruments harbored opportunistic, pathogenic, and/or allergenic microorganisms. The highest concentrations of microorganisms were found consistently at the mouthpiece end, but there was evidence of contamination throughout the instruments and their cases. The close proximity of contaminated mouthpieces to the oral cavity could facilitate local and systemic dissemination of the resident opportunistic, pathogenic, and/or allergenic microorganisms. General dentists should determine whether patients play a brass or woodwind instrument and be aware of the possible impact of this activity on the oral cavity and the entire body.

Evaluation of cleansing methods for previously worn prostheses.

STATEMENT OF PROBLEM: Although there are many product claims that address the issue of denture sanitization, controlled scientific studies on previously worn dentures have not been performed. PURPOSE: The purpose of this study was to evaluate procedures directed at sanitizing previously worn contaminated dentures from two regions of the United States. MATERIALS AND METHODS: This study examined 51 previously worn dentures from two regions. An established method of denture retrieval, sectioning, and culturing was used, including isolation of anaerobes. Evaluation of microbial contamination posttreatment was used to determine the effects of soaking dentures in Polident (US and European formulations) for varying periods of times/temperatures, microwaving dentures with varying temperatures, sonicating dentures, and immersing the dentures while using a vacuum. A combination of analysis of variance (ANOVA) and general linear model (GLM) of the SPSS was used to analyze the data with P < .05 being considered statistically significant when using a two-tailed test. RESULTS: While all Polident treatments were found to significantly reduce microorganism loads in dentures, extended soaking (8 hours) and 65 degrees C (5 minutes) were the most effective. Microwaving was slightly more effective than either sonication or vacuum. Regardless the treatment, dentures underwent sanitization rather than sterilization. CONCLUSIONS: Denture-borne microorganisms can be significantly reduced by using a Polident solution for 8 hours at room temperature or for 5 minutes at 65 degrees C. Microwaving, sonication, and use of a vacuum were less effective. ClLINICAL IMPLICATIONS The importance of daily use of Polident solution for 8 hours or for 5 minutes at 65 degrees C to sanitize worn prostheses must be stressed.

Evaluation of microbial flora found in previously worn prostheses from the Northeast and Southwest regions of the United States.

STATEMENT OF PROBLEM: Denture-induced stomatitis is a recognized clinical challenge. The responsible microorganisms have not been delineated and may differ among regions of the United States. PURPOSE: The purpose of this study was to identify the microorganisms found in dentures from 2 geographic regions. MATERIAL AND METHODS: Previously worn dentures from 51 available subjects living in the Southwest (41) and Northeast (10) were aseptically retrieved in sterile plastic bags. A posterior piece of the mandibular denture was removed and sampled on appropriate media under anaerobic conditions. The remaining denture material was divided into 7 equal pieces. Each piece was touched to appropriate aerobic media and incubated at 37 degrees C. Bacteria and yeasts were identified using standard clinical laboratory procedures. Data were analyzed by using descriptive statistics. Denture fragments were further analyzed by scanning electron microscopy (SEM). RESULTS: A total of 916 isolates were carried to final speciation. Of these, 711 were aerobic bacteria, 67 were anaerobic bacteria, 125 were yeasts, and 13 were amoebae. Microorganisms were found on the denture surfaces and interstices (denture pores). Most subjects wore their dentures for extended periods without sanitization. SEM analyses confirmed substantial porosity of the denture material with microbial penetration and biofilm formation within the pores. CONCLUSIONS: A wide range of potentially pathogenic microorganisms was found in dentures. There were also regional differences in the microbial flora.

Possible disease transmission by contaminated mouthguards in two young football players.

Previous studies have demonstrated that athletic mouthguards worn by ice hockey and football players harbor large numbers of bacteria, yeasts, and molds, some of which are either opportunistic or frank pathogens. This article details the clinical history of two junior high school football players. The first player had cellulitis of the leg after a non-break injury. The same unusual bacterium was isolated from both the athletic mouthguard and abscess cultures from the wound. The second patient suffered an attack of exercise-induced asthma so severe that his inhaler could not control the symptoms enough for him to resume play. This child's mouthguard was contaminated with five different species of mold. The clinical implications of mouthguard contamination, possible avenues of disease transmission, and recommendations for mouthguard care are discussed.

Effect of outer membrane permeabilisation on intrinsic resistance to low triclosan levels in Pseudomonas aeruginosa.

The present study was undertaken to investigate the possibility that outer cell envelope impermeability might be involved in the intrinsic resistance of Pseudomonas aeruginosa to low levels of the hydrophobic biocide triclosan. Macrobroth dilution and batch cultural turbidimetric assays were employed to assess the ability of compounds that render the Gram-negative outer membrane permeable to non-polar molecules to sensitise cell envelope variants to triclosan. Pseudomonas aeruginosa strains possessing highly refractory (PAO1) and atypically permeable (Z61) outer cell envelopes as well as a PAO1 derivative lacking four multidrug efflux pumps (YM64) were examined. Whilst the triclosan minimal inhibitory concentrations (MICs) differed dramatically for both PAO1 and Z61, significant decreases were seen for both strains in the presence of the outer membrane permeabiliser polymyxin B-nonapeptide. Strain YM64 was as resistant to triclosan as strain PAO1. Turbidimetric assessments of batch cultural growth kinetics revealed that the three chemically unrelated outer membrane permeabilisers polymyxin B-nonapeptide, compound 48/80 and ethylenediaminetetraacetate (EDTA) sensitised all strains to a sub-MIC concentration of triclosan (2.0 microg/mL). These data support the notion that the outer membrane exclusionary properties of P. aeruginosa for non-polar molecules confer intrinsic resistance to low concentrations of triclosan such as might be expected to occur in environmental residues. Moreover, a role for outer cell envelope impermeability is suggested for resistance to high triclosan concentrations in vitro.

Evaluation of the sanitization effectiveness of a denture-cleaning product on dentures contaminated with known microbial flora. An in vitro study.

OBJECTIVES: To see if dentures contaminated with Staphylococcus aureus, Pseudomas aeruginosa, Bacillus cereus, Candida albicans, and herpes simplex virus 1 could be effectively decontaminated by using Medical Tabs for Dentures. METHOD AND MATERIALS: Ten methylmethacrylate dentures with processed soft liners (soft-liner dentures) and 10 methylmethacrylate dentures without processed soft liners (hard dentures) were aseptically fragmented and individually incubated with a target microorganism. Test denture fragments were immersed in Medical for 5 minutes, vortexed for 5 minutes, and serially diluted onto media. The control denture fragments were similarly treated in sterile water. For virus contamination, denture fragments were contaminated with 1.2 x 10(9) tissue culture infective dose (TCID)50/mL. They were treated with either Medical for 5 minutes (test fragments) or water (controls) for 5 minutes. Serial dilutions were performed and viral (TCID)50/mL titers were calculated using the Reed-Muench method. RESULTS: Medical treatments effectively eliminated C. albicans, S. aureus, and P. aeruginosa from soft-liner dentures. Treatment of hard dentures eradicated C. albicans and reduced the numbers of S. aureus and P. aeruginosa to < 10. B. cereus showed a reduction of 10 microorganisms in hard dentures while the soft-liner dentures did not show an appreciable reduction. Viral analyses found that both types of dentures retained large amounts of virus when washed with water, but no virus was recovered from any of the 40 samples treated with Medical. CONCLUSION: A single use of Medical Tabs for Dentures is effective in eliminating certain species of microorganisms, including selected viruses, in vitro.

A statistical comparison of denture sanitation using a commercially available denture cleaner with and without microwaving.

Polymethyl-methacrylate dentures, worn by patients for periods ranging from 12 days to 48 years, were cultured and found to be heavily contaminated with a variety of microorganisms both externally and internally. A commercially available denture sanitizer, used as prescribed by the manufacturer, was ineffective at decontaminating the dentures. This study examined the effectiveness of this denture sanitizer when used in combination with a microwaving procedure. Statistical methods were used to compare the decontamination results of the denture sanitizer applied with and without microwaving. The statistical results indicated that the dentures were decontaminated most effectively when the denture sanitizer was used in conjunction with a two-minute microwave procedure.

Microbiota found in protective athletic mouthguards.

BACKGROUND: Protective athletic mouthguards (PAM) produce oral mucosal injuries and may be associated with other systemic conditions. HYPOTHESIS: With wear, PAM become contaminated by a range of microorganisms. The number of microorganisms in PAM can be reduced by daily use of an antimicrobial solution. STUDY TYPE: Case series. STUDY DESIGN AND METHODS: Sixty-two division I football player volunteers were divided into 4 groups, using PAM for varying lengths of time before surrendering them for microbial analysis. One group had their PAM soaked in an antimicrobial solution between uses. The PAM were analyzed qualitatively and quantitatively for bacteria, yeasts, and fungi, using previously accepted methods. RESULTS: The 62 football players surrendered a total of 81 PAM for microbial analysis. The PAM yielded 154 gram-positive cocci, 150 gram-positive bacilli, 21 gram-negative cocci, 31 gram-negative bacilli, 22 yeasts, and 107 molds. The most common species of gram-positive cocci were Staphylococcus spp. and Micrococcus spp. Only 3 PAM (4%) were positive for Staphylococcus aureus. The most common species of gram-positive bacilli were Brevibacterium spp. and Cellulomonas spp. The most common species of yeasts were Candida parapsilosis and Rhodotorula mucilaginosa, while the most common species of mold were Cochliobolus spp. and Penicillium chrysogenum. Soaking the PAM in an antimicrobial solution between uses substantially reduced the numbers of microorganisms. CONCLUSIONS: Substantial microbial contamination of PAM occurs with use. The microbial load can be reduced by soaking in an antimicrobial solution between uses. CLINICAL RELEVANCE: PAM are contaminated by microorganisms that have the potential to produce oral and systemic diseases. They should be sanitized daily and changed when they become sharp and/or jagged.

Protective athletic mouthguards: do they cause harm?

BACKGROUND: Protective athletic mouthguards (PAMs) have been worn in competitive sports for more than 100 years. Today, participants in contact and noncontact sports wear PAMs. HYPOTHESIS: Wearing a PAM produces oral injury. STUDY TYPE: Case series. STUDY DESIGN AND METHODS: Sixty-two Division I football players voluntarily participated in the study. Before the beginning of the season, each player underwent a thorough oral examination, and all abnormal oral findings were photographed (hyperkeratosis, erythema, ulceration, and combinations thereof). At midseason, 14 players were given complete oral examinations, with all abnormal oral findings documented. At season end, all remaining players (n = 53) had complete oral examinations and photographs taken of abnormal oral findings. RESULTS: The preseason examination of 62 players found a total of 85 lesions (1.4 lesions per player) on the gingiva (n = 17), buccal mucosa (n = 60), and palate (n = 8). The 14 midseason players had 28 lesions (2.0 lesions per player) on gingiva (n = 8), buccal mucosa (n = 16), and tongue (n = 4). At season end, the 53 remaining players had 198 lesions (3.7 per player) on the gingiva (n = 96), buccal mucosa (n = 79), tongue (n = 18), and palate (n = 5). In addition, the lesion intensity scores progressively increased over the season. Because the palate did not come into direct contact with the PAM, it was used as an internal control. CONCLUSION: The wearing of a PAM may increase the number and intensity of oral mucosal injuries, which may cause localized soft tissue reactions such as hyperkeratosis, erythema, and ulceration. CLINICAL RELEVANCE: Because the PAM reduces tooth injury but may cause oral lesions, it should be sanitized daily and changed regularly and replaced whenever it becomes sharp and jagged or when the athlete develops an irritation in the mouth.