Oral Bacterial Infection Research Articles

Bactericidal Effects of a Prosthesis Cleaning Tablet

Background: Hygiene and maintenance of removable prostheses are very important for the oral health. Elderly patients are not capable of this affair since they might have diseases in addition to being old; thus, they require new alternative methods. Objectives: The purpose of this study was to compare the disinfecting effects of three substances, water, normal saline and denture cleaning tablets Corega that patients commonly use as denture cleaning, against oral bacterial infections. Patients and Methods: In this study, complete maxillary dentures of 138 elderly individuals living in a nursing home (46 females and 92 males) with a mean age of 9 ± 75 years were studied. Their prostheses were soaked for 15 minutes randomly into one of the following substances: water, normal saline, or a solution containing denture cleaning tablets (Corega). Before and after this operation, samples were obtained by a third person using microbiological studies swabs. The samples were cultured and the colony forming units (CFU) were obtained. Data were evaluated by one-way ANOVA test. Results: Statistically, Corega reduced bacterial infections significantly more than water and normal saline (P = 0.0001). Water and normal saline had equal effects on reducing CFU. Conclusions: Denture cleaning tablet, Corega, is recommended for cleaning the prostheses, but using water or saline alone is not recommended.

The immune strategy and stress response of the Mediterranean species of the Bemisia tabaci complex to an orally delivered bacterial pathogen.

BackgroundThe whitefly, Bemisia tabaci, a notorious agricultural pest, has complex relationships with diverse microbes. The interactions of the whitefly with entomopathogens as well as its endosymbionts have received great attention, because of their potential importance in developing novel whitefly control technologies. To this end, a comprehensive understanding on the whitefly defense system is needed to further decipher those interactions.Methodology/Principal FindingsWe conducted a comprehensive investigation of the whitefly's defense responses to infection, via oral ingestion, of the pathogen, Pseudomonas aeruginosa, using RNA-seq technology. Compared to uninfected whiteflies, 6 and 24 hours post-infected whiteflies showed 1,348 and 1,888 differentially expressed genes, respectively. Functional analysis of the differentially expressed genes revealed that the mitogen associated protein kinase (MAPK) pathway was activated after P. aeruginosa infection. Three knottin-like antimicrobial peptide genes and several components of the humoral and cellular immune responses were also activated, indicating that key immune elements recognized in other insect species are also important for the response of B. tabaci to pathogens. Our data also suggest that intestinal stem cell mediated epithelium renewal might be an important component of the whitefly's defense against oral bacterial infection. In addition, we show stress responses to be an essential component of the defense system.Conclusions/SignificanceWe identified for the first time the key immune-response elements utilized by B. tabaci against bacterial infection. This study provides a framework for future research into the complex interactions between whiteflies and microbes.

English

BACKGROUND: There has been increasing attention paid in recent years to the possibility that oral bacterial infection, particularly periodontal disease may influence the initiation and or progression of systemic diseases. These studies confirm the observation that heart disease is the most commonly found systemic condition in patients with periodontal disease. Moreover, the literature has also highlighted substantial evidence indicating the presence of gram negative periodontal pathogens in atheromatous plaques. AIMS : The present study intends to investigate the possible association between periodontal health and coronary artery disease by evaluating periodontal status, association between the periodontal plaque and coronary atheromatous plaques for presence of P.gingivalis. SETTINGS AND DESIGN: A case control study was designed with 07 patients who had underwent coronary endarterectomy for CVD and 28 controls . The periodontal examination for cases was performed one day before vascular surgery and the controls were clinically examined. METHODS AND MATERIAL : The atheromatous plaque sample collected during endarterectomy and the Intraoral plaque samples were subjected to PCR for identification of P.gingivalis. The presence of periodontal bacteria DNA in coronary atheromatous plaques and subgingival plaque samples of the same patients was confirmed by this study. STATISTICAL ANALYSIS USED : Means and proportions for personal characters, major risk factors and clinical parameters were calculated for both the groups. The significance of any difference in means was tested by using “Students t test”, and the significance of any difference in proportions was tested by using DunnSidak Adjusted p Value. RESULTS : During the microbial analysis of plaque samples by PCR in group A it was seen that Porphyromonas gingivalis in 100 % of the samples. Microbial analysis of endarterectomy samples by PCR in group A shows that Porphyromonas gingivalis was found in 71.43 % of endarterectomy samples. Porphyromonas gingivalis was present in all the plaque samples and 5 atheroma samples of Group A. CONCLUSIONS : A correlation was established between putative bacteria contributing to atheromatous plaques and species associated with periodontal disease. One particularly important study to be carried out is the investigation of a possible clinically meaningful reduction in coronary heart disease resulting from the prevention or treatment of periodontal disease.

Cigarette Smoke-ExposedCandida albicansIncreased Chitin Production and Modulated Human Fibroblast Cell Responses

The predisposition of cigarette smokers for development of respiratory and oral bacterial infections is well documented. Cigarette smoke can also contribute to yeast infection. The aim of this study was to investigate the effect of cigarette smoke condensate (CSC) on C. albicans transition, chitin content, and response to environmental stress and to examine the interaction between CSC-pretreated C. albicans and normal human gingival fibroblasts. Following exposure to CSC, C. albicans transition from blastospore to hyphal form increased. CSC-pretreated yeast cells became significantly (P < 0.01) sensitive to oxidation but significantly (P < 0.01) resistant to both osmotic and heat stress. CSC-pretreated C. albicans expressed high levels of chitin, with 2- to 8-fold recorded under hyphal conditions. CSC-pretreated C. albicans adhered better to the gingival fibroblasts, proliferated almost three times more and adapted into hyphae, while the gingival fibroblasts recorded a significantly (P < 0.01) slow growth rate but a significantly higher level of IL-1β when in contact with CSC-pretreated C. albicans. CSC was thus able to modulate both C. albicans transition through the cell wall chitin content and the interaction between C. albicans and normal human gingival fibroblasts. These findings may be relevant to fungal infections in the oral cavity in smokers.

Overexpression of receptor for advanced glycation end products and high-mobility group box 1 in human dental pulp inflammation.

High mobility group box 1 (HMGB1), a nonhistone DNA-binding protein, is released into the extracellular space and promotes inflammation. HMGB1 binds to related cell signaling transduction receptors, including receptor for advanced glycation end products (RAGE), which actively participate in vascular and inflammatory diseases. The aim of this study was to examine whether RAGE and HMGB1 are involved in the pathogenesis of pulpitis and investigate the effect of Prevotella intermedia (P. intermedia) lipopolysaccharide (LPS) on RAGE and HMGB1 expression in odontoblast-like cells (OLC-1). RAGE and HMGB1 expression levels in clinically inflamed dental pulp were higher than those in healthy dental pulp. Upregulated expression of RAGE was observed in odontoblasts, stromal pulp fibroblasts-like cells, and endothelial-like cell lining human pulpitis tissue. Strong cytoplasmic HMGB1 immunoreactivity was noted in odontoblasts, whereas nuclear HMGB1 immunoreactivity was seen in stromal pulp fibroblasts-like cells in human pulpitis tissue. LPS stimulated OLC-1 cells produced HMGB1 in a dose-dependent manner through RAGE. HMGB1 translocation towards the cytoplasm and secretion from OLC-1 in response to LPS was inhibited by TPCA-1, an inhibitor of NF-κB activation. These findings suggest that RAGE and HMGB1 play an important role in the pulpal immune response to oral bacterial infection.

Chronic exposure to oral pathogens and autoimmune reactivity in acute coronary atherothrombosis.

Background. It has been hypothesized that various infective agents may activate immune reactions as part of the atherosclerotic process. We aimed to investigate the interrelationship between chronic exposure to oral pathogens and immune-inflammatory response in patients with acute coronary atherothrombosis. Patients and Methods. The study included 200 participants from Serbia: 100 patients with acute myocardial infarction (MI), and 100 age- and sex-matched controls. Antibodies to oral anaerobes and aerobes were determined as well as autoantibodies to endothelial cells, beta-2 glycoprotein I, platelet glycoprotein IIb/IIIa and anticardiolipin. Interleukin-6 (IL-6) and C-reactive protein (CRP) were measured. Results. The mean serum antibodies to oral anaerobes tended to be higher among subjects with MI (0.876 ± 0.303 versus 0.685 ± 0.172 OD, P < 0.001). Similarly, antibody levels against oral aerobes in patients were significantly different from controls. Antibodies against endothelial cell, beta-2 glycoprotein I, platelet glycoprotein IIb/IIIa, anticardiolipin along with CRP and IL-6 were highly elevated in patients. The levels of antibodies to oral bacteria showed linear correlation with tissue antibodies, CRP and IL-6. Conclusion. Antibody response to chronic oral bacterial infections and host immune response against them may be responsible for the elevation of tissue antibodies and biomarkers of inflammation which are involved in acute coronary thrombosis development.

Multi‐organ injuries caused by lipopolysaccharide‐induced periodontal inflammation in rats: role of melatonin

Periodontitis, a chronic inflammatory disease caused by oral bacterial infection, is considered to be a risk factor for systemic diseases including diabetes mellitus, bacterial pneumonia, hyperlipidemia and atherosclerosis. The aim of this study was to evaluate the effectiveness of melatonin against periodontal inflammation-induced multiple organ injury in rats. Eighteen female Wistar albino rats were randomly divided into three groups of six rats each: control; lipopolysaccharide (LPS); and LPS + melatonin. During the experimental period (10d) all rats in the LPS and LPS + melatonin groups were given 10μL of LPS (from a 10mg/mL standard solution of LPS dissolved in saline) on days 1, 3 and 5. The rats in the LPS + melatonin group were given 50mg/kg of melatonin, daily for 10d, starting on day 1 after the administration of LPS. All rats were killed at the end of the experimental period. Liver, kidney and lung tissues were removed for investigation by light microscopy. The levels of serum aspartate aminotransferase (AST), alanine transaminase (ALT) and blood urea nitrogen (BUN) were significantly increased in the LPS group compared with the LPS+ melatonin group (p<0.05). There was no significant change in the serum creatinine levels in the groups. However, the changes in serum AST, ALT and BUN levels in the experimental groups did not correlate with changes in histological data. Both LPS and LPS + melatonin groups displayed structural features similar to those of the control group. The results revealed that increased serum AST, ALT and BUN levels following periodontitis are ameliorated with melatonin treatment.

Links demystified: Periodontitis and cancer.

Cancer is marked by the uncontrolled growth of cells, tissue invasion and metastasis to various organs via the circulatory and lymphatic systems. Recent data have expanded the concept that inflammation is a critical component of tumor progression. Many cancers arise from sites of infection, chronic irritation, and inflammation. The tumor microenvironment, which is largely orchestrated by inflammatory cells, is an indispensable participant in the neoplastic process, fostering proliferation, survival, and migration. Periodontal disease, a chronic inflammatory condition is characterized by an oral bacterial infection leading to inflammation within the supporting tissues of the teeth, which often leads to the destruction of the periodontal tissues and alveolar bone that support the teeth. This oral inflammation often has systemic effects leading to an increased concentration of circulating inflammatory markers with the severity of disease being correlated directly with levels of serum inflammatory markers. Periodontal infection has been linked to organ and systemic diseases. There is documented evidence of significant associations between cancer of the lung, kidney, pancreas, hematological and oral cancers, and periodontal disease. This articles reviews and summarizes the possible biological mechanisms involved between periodontal infection and cancer.

Functional salivary gland regeneration by transplantation of a bioengineered organ germ

Salivary gland hypofunction, also known as xerostomia, occurs as a result of radiation therapy for head cancer, Sjögren’s syndrome or aging, and can cause a variety of critical oral health issues, including dental decay, bacterial infection, mastication dysfunction, swallowing dysfunction and reduced quality of life. Here we demonstrate the full functional regeneration of a salivary gland that reproduces the morphogenesis induced by reciprocal epithelial and mesenchymal interactions through the orthotopic transplantation of a bioengineered salivary gland germ as a regenerative organ replacement therapy. The bioengineered germ develops into a mature gland through acinar formations with a myoepithelium and innervation. The bioengineered submandibular gland produces saliva in response to the administration of pilocarpine and gustatory stimulation by citrate, protects against oral bacterial infection and restores normal swallowing in a salivary gland-defective mouse model. This study thus provides a proof-of-concept for bioengineered salivary gland regeneration as a potential treatment of xerostomia.

Halitosis Vaccines Targeting FomA, a Biofilm-bridging Protein of Fusobacteria nucleatum

Halitosis (bad breath) is estimated to influence more than half of the world's population with varying degree of intensity. More than 85% of halitosis originates from oral bacterial infections. Foul-smelling breath mainly results from bacterial production of volatile sulfur compounds (VSCs) such as hydrogen sulfide and methyl mercaptan. To date, major treatments for elimination of oral malodor include periodontal therapy combined with antibiotics or antimicrobial agents, and mechanical approaches including tooth and tongue cleaning. These treatments may transiently reduce VSCs but carry risks of generating toxicity, increasing resistant strains and misbalancing the resident human flora. Therefore, there is a need to develop alternative therapeutic modalities for halitosis. Plaque biofilms are the principal source for generating VSCs which are originally metabolized from amino acids during co-aggregation of oral bacteria. Blocking the bacterial coaggregation, therefore, may prevent various biofilm-associated oral diseases such as periodontitis and halitosis. Fusobacterium nucleatum (F. nucleatum), a Gram-negative anaerobe oral bacterium, is a main bacterial strain related to halitosis. Aggregation of F. nucleatum with other bacteria to form plaque biofilms in oral cavity causes bad breath. FomA, the major outer membrane protein of F. nucleatum, recruits other oral pathogenic bacteria such as Porphyromonas gingivalis (P. gingivalis) in the periodontal pockets. A halitosis vaccine targeting F. bacterium FomA significantly abrogates the enhancement of bacterial co-aggregation, biofilms, production of VSCs, and gum inflammation mediated by an inter-species interaction of F. nucleatum with P. gingivalis, which suggests FomA of F. nucleatum to be a potential target for development of vaccines or drugs against bacterial biofilm formation and its associated pathogenicities.

Functional Analysis of PGRP-LA in Drosophila Immunity

PeptidoGlycan Recognition Proteins (PGRPs) are key regulators of the insect innate antibacterial response. Even if they have been intensively studied, some of them have yet unknown functions. Here, we present a functional analysis of PGRP-LA, an as yet uncharacterized Drosophila PGRP. The PGRP-LA gene is located in cluster with PGRP-LC and PGRP-LF, which encode a receptor and a negative regulator of the Imd pathway, respectively. Structure predictions indicate that PGRP-LA would not bind to peptidoglycan, pointing to a regulatory role of this PGRP. PGRP-LA expression was enriched in barrier epithelia, but low in the fat body. Use of a newly generated PGRP-LA deficient mutant indicates that PGRP-LA is not required for the production of antimicrobial peptides by the fat body in response to a systemic infection. Focusing on the respiratory tract, where PGRP-LA is strongly expressed, we conducted a genome-wide microarray analysis of the tracheal immune response of wild-type, Relish, and PGRP-LA mutant larvae. Comparing our data to previous microarray studies, we report that a majority of genes regulated in the trachea upon infection differ from those induced in the gut or the fat body. Importantly, antimicrobial peptide gene expression was reduced in the tracheae of larvae and in the adult gut of PGRP-LA-deficient Drosophila upon oral bacterial infection. Together, our results suggest that PGRP-LA positively regulates the Imd pathway in barrier epithelia.

Periodontitis and Rheumatoid arthritis – A Review

The periodontal disease is an inflammatory condition of the supporting structres of the teeth. The presence of rheumatoid arthritis or other systemic inflammatory disease may increase the severity of the periodontal disease. The studies published in the past reveals that the oral bacterial infections and inflammation seemed to be linked directly to the etiopathogenesis of rheumatoid arthritis. There are findings support the impact of periodontal pathogens, such as Porpyromonas gingivalis on citrullination, and the association of periodontitis in rheumatoid arthritis patients with serospecificity toward rheumatoid factor and the anti-cyclic citrullinated peptide antibody 1 .In this review the common etiology, pathogenesis and immunogenetics of two

Microwave를 이용한 칫솔 살균효과

Objectives : The purpose of this study is to analyze the sterilizing effects of toothbrushes by administering bacteria into toothbrushes and reproducing the antibacterial effects using a microwave oven. Methods : The heads of four-row mid-strength toothbrushes were cut, put in a bacterial solution (<TEX>$3{\times}10^9cells/ml$</TEX>) for vortexing, and sterilized with microwaves for 0, 30, and 60 seconds. They were then moved into four tubes containing DW 10 ml and suspended in a vortex mixer for two minutes to separate bacteria from them. DW 9ml was added by 1ml of bacteria for dilution of <TEX>$10{\sim}10^6$</TEX> times. It was then administered to the BHI agar plate by 0.1ml and cultured at <TEX>$37^{\circ}C$</TEX> for 24 hours. Total number of bacteria adhered to a toothbrush was obtained by multiplying the number of colonies by the dilution factor. The experiment was done in the first, second, and third step, being repeated in a normal temperature drier (<TEX>$23^{\circ}C$</TEX>) after 5, 9 and 24 hours. Results : The results of the experiment revealed that the sterilizing effects were 95% or over. When toothbrushes were sterilized for 60 seconds, the number of colonies is about 11 after drying for 5 hours, 7 after drying for 9 hours and 2 after drying for 24 hours. The sterilizing effects reached 98% when the bacteria-administered toothbrush was sterilized for 1 minute after drying for 24 hours. Conclusions : The results demonstrated that toothbrush sterilizing by using microwave is a suitable way to prevent cross-contamination of toothbrushes by oral bacterial infection and thus easy to use at home. However, this study suggests that toothbrush sterilizing by using microwave should be limited within two times a week because the physical properties of toothbrush might be changed.

The Impact of Porphyromonas gingivalis Lipids on Apoptosis of Primary Human Chondrocytes

The role of oral bacterial infections including periodontal disease in the pathogenesis of rheumatoid arthritis (RA) has gained increasing interest. Among the major periodontal pathogens, Porphyromonas gingivalis has been mostly associated with RA pathogenesis. The aim of this study was to analyze the effect of P. gingivalis total lipid (TL) fraction and dihydroceramides, as potent virulence factors, on human primary chondrocytes. Primary chondrocyte cultures were incubated with P. gingivalis phosphoglycerol dihydroceramide (PG DHC) lipids, the TL fraction or phosphoethanolamine dihydroceramide. Cell morphology changes were determined by phase contrast light microscopy. Early and late apoptosis cell analysis was performed by Annexin-V, active caspases, and 7-Aminoactinomycin D staining, and examined by flow cytometry, and cell necrosis was evaluated by lactate dehydrogenase release. Procaspase-3 activation was determined by Western blot analysis. Microscopic analysis showed altered cell morphology and cell shrinkage following incubation with P. gingivalis TLs and PG DHC lipids. Flow cytometry demonstrated an increase of Annexin-V positive and active caspases positive chondrocytes after incubation with TL and PG DHC fractions but not after phosphoethanolamine dihydroceramide (control lipid) treatment or in untreated control cells. Furthermore, Western blot analysis showed an early cleavage of procaspase-3 after 1 hr. Significant lactate dehydrogenase release following incubation with P. gingivalis lipids was demonstrated. The present data demonstrate that P. gingivalis lipids promote apoptosis in primary human chondrocytes, and thereby may contribute to the joint damage seen in the pathogenesis of RA.

Autocrine and paracrine unpaired signaling regulate intestinal stem cell maintenance and division

The Janus kinase (JAK) signal transducer and activator of transcription (STAT) pathway is involved in the regulation of intestinal stem cell (ISC) activity to ensure a continuous renewal of the adult Drosophila midgut. Three ligands, Unpaired 1, Unpaired 2 and Unpaired 3 (Upd1, Upd2 and Upd3, respectively) are known to activate the JAK/STAT pathway in Drosophila. Using newly generated upd mutants and cell-specific RNAi, we showed that Upd1 is required throughout the fly life to maintain basal turnover of the midgut epithelium by controlling ISC maintenance in an autocrine manner. A role of Upd2 and Upd3 in basal conditions is discernible only in old gut, where they contribute to increased ISC abnormal division. Finally, upon an acute stress such as oral bacterial infection, we showed that Upd3 is released from enterocytes and has an additive effect with Upd2 to promote rapid epithelial regeneration. Taken together, our results show that Upd ligands are required to maintain the midgut homeostasis under both normal and pathological states.

The biomimetic apatite-cefalotin coatings on modified titanium

Dental implant failure often occurs due to oral bacterial infection. The aim of this study was to demonstrate that antibiotic efficacy could be enhanced with modified titanium. First, the titanium was modified by anodization and heat-treatment. Then, a biomimetic coating process was completed in two steps. Surface characterization was performed with scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. Release of antibiotic was evaluated by UV/VIS spectrometry, and the antibacterial effect was evaluated on Streptococcus mutans. After the second coating step, we observed a thick homogeneous apatite layer that contained the antibiotic, cefalotin. The titanium formed a rutile phase after the heat treatment, and a carbonated apatite phase appeared after biomimetic coating. We found that the modified titanium increased the loading of cefalotin onto the hydroxyapatite coated surface. The results suggested that modified titanium coated with a cefalotin using biomimetic coating method might be useful for preventing local post-surgical implant infections.

Brain abscess associated with Aggregatibacter actinomycetemcomitans: case report and review of literature

An association between the oral bacterial species Aggregatibacter actinomycetemcomitans and systemic infection.

Photodynamic antimicrobial chemotherapy in dental practice

Photodynamic therapy (PDT) is a medical treatment that uses light to activate a photosensitizing agent (photosensitizer) in the presence of oxygen. Its use in dentistry is increasing, particularly for the treatment of oral cancer, and bacterial and fungal infection. This article provides an overview of PDT

Effects of Iron Status and Iron Supplementation on Salmonella Typhimurium and Plasmodium Yoelii Infection In Mice

AbstractAbstract 2052▪To clarify the interactions between iron status, oral iron supplementation, and bacterial and malarial infections, we examined iron-replete mice and mice with dietary iron deficiency infected with Salmonella typhimurium, Plasmodium yoelii, or both, with and without oral iron administration. These studies were designed to identify potential mechanisms underlying the increased risk of severe illness and death in children in a malaria-endemic region who received routine iron and folic acid supplementation during a randomized, controlled trial in Pemba, Tanzania (Sazawal et al. Lancet 2006;367:133-43). To this end, weanling C57BL/6 female mice were fed an iron-replete or an iron-deficient diet, the latter of which resulted in severe iron deficiency anemia. Groups of mice were then infected by intraperitoneal injection of Salmonella typhimurium strain LT2, Plasmodium yoelii strain 17X parasites, or both. With Salmonella infection alone, iron-deficient mice had a median survival (7.5 days, N=8) approximately half that of iron-replete mice (13 days, N=10, p<0.0001). At death, the mean level of bacteremia was significantly higher in infected iron-deficient mice. In blood cultures performed at death, all iron-deficient mice were bacteremic, but bacteria were detected in only 4 of 10 iron-replete mice. Both iron-deficient and iron-replete Salmonella-infected mice had gross hepatosplenomegaly with hepatitis, distorted hepatic and splenic architecture, massive expansion of the splenic red pulp with inflammatory cells, and Gram-negative bacilli by tissue Gram stain. With P. yoelii infection alone, iron-deficient and iron-replete mice cleared the infection at similar rates (by ~13 days following infection, N=5 in each group) and no deaths due to parasitemia occurred. With Salmonella and P. yoelii co-infection, death was earlier than with Salmonella alone in iron-replete mice (median survival of 10 vs. 13 days; N=10 in each group; p=0.005), but not in iron-deficient mice (median survival of 7 vs. 7.5 days; N=10 and 8, respectively; p=0.8). To examine the effect of short-term oral iron supplementation with Salmonella infection alone, mice received daily iron (ferrous sulfate, 1 mg/kg) by gavage for 4 days before infection with Salmonella, and supplementation continued for a total of 10 days. After gavage, plasma non-transferrin-bound iron (NTBI) appeared at 1–2 hours with a mean peak level of approximately 5 μM. In iron-deficient mice, short-term oral iron supplementation did not fully correct the iron deficiency anemia or replenish iron stores. Oral iron supplementation reduced the median survival of both iron-deficient and iron-replete Salmonella-infected mice by approximately 1 day; the difference was significant only in the iron-replete group (N=5, p<0.05). In summary, these results indicate that iron deficiency decreases the survival of Salmonella-infected mice; the median survival of iron-deficient mice was approximately half that of those that were iron replete. These observations are similar to those in the Pemba sub-study in which iron-deficient children given placebo had a 200% increase in the risk of adverse events relative to iron-replete children. Iron deficiency had no apparent effect on the course of infection with P. yoelii but further studies with more virulent Plasmodium species are needed. Co-infection with Salmonella and Plasmodium significantly increased mortality as compared to single infections, but only in iron-replete mice. Oral iron supplementation of Salmonella-infected mice significantly decreased the median survival, but only of iron-replete animals; however, our study may have had insufficient power to detect an effect on iron-deficient mice. Systematic examination in mice of the effect of iron supplements on the severity of malarial and bacterial infection in iron-replete and iron-deficient states may ultimately help guide the safe and effective use of iron interventions in humans in areas with endemic malaria. Disclosures:No relevant conflicts of interest to declare.

Part II: Crystalline Fluorapatite-Coated Hydroxyapatite Implant Material: A Dog Study With Histologic Comparison of Osteogenesis Seen With FA-Coated HA Grafting Material Versus HA Controls: Potential Bacteriostatic Effect of Fluoridated HA

Success of osteogenesis in bone graft procedures can be enhanced by inhibiting oral bacterial infections through the use of prophylactic bacteriostatic fluoride within the grafting environment. Ideally, the fluoride ion should be chemically sequestered and thus unavailable unless needed at times during the process of early infection. As fluoride within fluorapatite is tightly bound at neutral pH and becomes available only during acidic conditions, fluorapatite is an ideal store for the fluoride ion which becomes released for bacteriostasis only during an acidic environment found with incipient bacterial infection. The purpose of this investigation was to compare the histologic properties of new bone formed surrounding fluorapatite (FA)-coated microcrystalline hydroxyapatite (HA) grafting material with comparable bone formed following the use of control HA material (OsteoGen, Impladent, Ltd, Holliswood, NY). The results of histologic analysis within dog studies here showed no detectable difference in new bone following therapeutic grafting procedures using each of the above 2 mineral coatings.