Interactions between oral commensal Candida and oral bacterial communities in immunocompromised and healthy children.

Candida species are usually found as commensal microorganisms in the oral cavity of healthy people. During chemotherapy, cytostatic drugs lead to depletion of the oral flora with the emergence of a dominant bacterial species. The transition from commensal to pathogenic state, further associated with yeast colonization and oral mucositis implies a replacement of the dominant microorganism by Candida albicans. This process goes plausibly through cooperation between C. albicans and bacteria. This study focused on the first step of cooperation between microorganisms isolated from the same oral flora either of leukemic or healthy children. C. albicans isolated from 8/20 children were cultured to display their noninvasive blastosporic yeast form and mixed with their dominant bacteria to study the capacity of planktonic aggregation and the early state of biofilm formation. None of the dominant bacteria opposed the presence of yeast, on the contrary, an interesting cooperation was observed. This behavior is apparently different from that observed when mixing the type strains. In fact, three mutated C. albicans strains display, by their spontaneous ability to form filament, enhanced risks of virulence for leukemic ill carriers. Despite such risks, neither oral nor systemic pathology were observed in ill patients probably because the study was conducted during the first course of chemotherapy and Candida colonization is related to the number of chemotherapeutic cycles. The presence of C. albicans during the initial cycle represents, by its ability to interact with oral bacteria, an actual threat for further cures.

Benefits of sea buckthorn (Hippophae rhamnoides) pulp oil-based mouthwash on oral health.

AIM: The purpose of this study was to conduct phytochemical analysis of sea buckthorn pulp oil and to evaluate the antimicrobial, anti-biofilm and antioxidant activities of its mouthwash form. METHODS AND RESULTS: Fatty acid composition of the sea buckthorn pulp oil was determined by GC-MS analysis, which revealed that, mono-unsaturated fatty acid, palmitoleic acid and saturated fatty acid, palmitic acid, were the major constituents. The antimicrobial and the anti-biofilm capacities of sea buckthorn pulp oil mouthwash form were evaluated against Streptococcus gordonii, Porphyromonas gingivalis, Actinomyces viscosus and Candida albicans, according to the European Norms, and the Biofilm Ring Test® , respectively. These activities were then compared with those of chlorhexidine and herbal mouthwashes. The sea buckthorn-based mouthwash was bactericidal against S. gordonii and P. gingivalis, bacteriostatic against A. viscosus and showed no antifungal effect. Regardless of the strains used, complete inhibition of biofilm formation was achieved. The antioxidant activity of this experimental mouthwash was also assessed by DPPH and NBT assays. CONCLUSION: Sea buckthorn mouthwash showed anti-biofilm activities against select single and multiple oral bacterial species. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, a mouthwash derived from sea buckthorn (Hippophae rhamnoides) pulp oil has been experimented, for the first time, in order to overcome the problem of a large number of available synthetic mouthwashes which have side effects on teeth, gums and mucous membranes. This mouthwash seemed to be a suitable alternative for a preventive agent for periodontal inflammation.

Treponema, Iron and Neurodegeneration.

Spirochetes are suspected to be linked to the genesis of neurological diseases, including neurosyphillis or neurodegeneration (ND). Impaired iron homeostasis has been implicated in loss of function in several enzymes requiring iron as a cofactor, formation of toxic oxidative species, inflammation and elevated production of beta-amyloid proteins. This review proposes to discuss the link that may exist between the involvement of Treponema spp. in the genesis or worsening of ND, and iron dyshomeostasis. Proteins secreted by Treponema can act directly on iron metabolism, with hemin binding ability (HbpA and HbpB) and iron reductase able to reduce the central ferric iron of hemin, iron-containing proteins (rubredoxin, neelaredoxin, desulfoferrodoxin metalloproteins, bacterioferritins etc). Treponema can also interact with cellular compounds, especially plasma proteins involved in iron metabolism, contributing to the virulence of the syphilis spirochetes (e.g. treponemal motility and survival). Fibronectin, transferrin and lactoferrin were also shown to be receptors for treponemal adherence to host cells and extracellular matrix. Association between Treponema and iron binding proteins results in iron accumulation and sequestration by Treponema from host macromolecules during systemic and mucosal infections.

The ambient aerosol characterization during the prescribed bushfire season in Brisbane 2013.

Prescribed burnings are conducted in Queensland each year from August until November aiming to decrease the impact of bushfire hazards and maintain the health of vegetation. This study reports chemical characteristics of the ambient aerosol, with a focus on source apportionment of the organic aerosol (OA) fraction, during the prescribed biomass burning (BB) season in Brisbane 2013. All measurements were conducted within the International Laboratory for Air Quality and Health (ILAQH) located in Brisbane's Central Business District. Chemical composition, degree of ageing and the influence of BB emission on the air quality of central Brisbane were characterized using a compact Time of Flight Aerosol Mass Spectrometer (cToF-AMS). AMS loadings were dominated by OA (64%), followed by, sulfate (17%), ammonium (14%) and nitrates (5%). Source apportionment was applied on the AMS OA mass spectra via the multilinear engine solver (ME-2) implementation within the recently developed Source Finder (SoFi) interface. Six factors were extracted including hydrocarbon-like OA (HOA), cooking-related OA (COA), biomass burning OA (BBOA), low-volatility oxygenated OA (LV-OOA), semivolatile oxygenated OA (SV-OOA), and nitrogen-enriched OA (NOA). The aerosol fraction that was attributed to BB factor was 9%, on average over the sampling period. The high proportion of oxygenated OA (72%), typically representing aged emissions, could possess a fraction of oxygenated species transfored from BB components on their way to the sampling site.

Dental abnormalities and preventive oral care in Schimke immuno-osseous dysplasia.

BACKGROUND: Schimke immuno-osseous dysplasia (SIOD) is a rare, severe, autosomal recessive disorder that results in spondyloepiphyseal dysplasia, renal dysfunction, immunodeficiency, facial dysmorphism and growth failure. Little is known about oral features associated with SIOD. Some of the dental anomalies encountered are specific to SIOD and have only been reported in individuals with SIOD. CASE REPORT: This paper describes the clinical and radiographic dental manifestations of SIOD in two Caucasian brothers. Both lived to be about 10 years old. After a variety of symptoms were reported, a diagnosis of SIOD was finally made when the brothers were, respectively, 5 and 8 years old. At that time, dental anomalies, such as dyschromia, bulbous crowns, short and thin roots, had not been taken into account to establish the diagnosis. However, knowledge of the dental features characteristic of this disease could have helped make the diagnosis. Although both were caries- and periodontal disease-free, special attention was focused on prevention, including dietary counselling, plaque control, oral hygiene instructions and the use of fluoridated toothpaste. FOLLOW-UP: The two patients were followed every 6 months, for over 2 years (until their death), by both a private dentist and a university hospital dentist, which helped them maintain good oral health. Oral hygiene was assessed at each appointment and fissure sealants were placed by the private practitioner on their first permanent molars. CONCLUSION: This report describes dental anomalies specific to SIOD that could facilitate diagnosis. Clinicians and dentists should work in collaboration to diagnose and treat children with SIOD. These patients require regular and specific dental management because of their fragile health and their characteristic dental anomalies. Ideally, preventive visits should be scheduled every 6 months in addition to curative visits as needed.

Investigation of phosphate adsorption onto ferrihydrite by X-ray photoelectron spectroscopy.

The objective of this study was to characterize phosphate adsorption onto synthetic 2-lines ferrihydrite using surface analysis by X-ray Photoelectron Spectroscopy and batch experiments. Surface analysis of ferrihydrite samples before phosphate sorption gives very reproducible Fe:O surface ratios of (1:3±0.1). Phosphate sorption onto ferrihydrite was investigated by means of pH, initial phosphate concentration, and ionic strength effects. Additionally, potential background electrolyte influence on phosphate adsorption was also determined. Phosphate uptake by ferrihydrite significantly increases with decreasing pH, with a maximum uptake of 104.8 mg PO4 g(-1) obtained at pH=4. Phosphate removal increases with the enhancement of ionic strength in agreement with the formation of inner-sphere complexes. The presence of chloride, nitrate, and sulfate showed no competing effect on phosphate removal efficiency. Sorption kinetics follow a pseudo-second order model (R(2)>0.99) and the Freundlich isotherm model adequately describes sorption (R(2)=0.995). The careful examination of high resolution Fe 2p, O 1s, and P 2p spectra before and after phosphate sorption allows the characterization of the modifications occurring onto the ferrihydrite surface. The binding energy of the P 2p peak agrees well with that observed in Fe-PO4 compounds. Additionally, binding energy shifts in the Fe 2p spectra combined to variations in the relative intensity of the components in the high resolution O 1s spectra illustrate well the formation of chemical bonding between iron and phosphate anions at the ferrihydrite surface.

Antibiotic content of selective culture media for isolation of Capnocytophaga species from oral polymicrobial samples.

UNLABELLED: In oral microbiome, because of the abundance of commensal competitive flora, selective media with antibiotics are necessary for the recovery of fastidious Capnocytophaga species. The performances of six culture media (blood agar, chocolate blood agar, VCAT medium, CAPE medium, bacitracin chocolate blood agar and VK medium) were compared with literature data concerning five other media (FAA, LB, TSBV, CapR and TBBP media). To understand variable growth on selective media, the MICs of each antimicrobial agent contained in this different media (colistin, kanamycin, trimethoprim, trimethoprim-sulfamethoxazole, vancomycin, aztreonam and bacitracin) were determined for all Capnocytophaga species. Overall, VCAT medium (Columbia, 10% cooked horse blood, polyvitaminic supplement, 3·75 mg l(-1) of colistin, 1·5 mg l(-1) of trimethoprim, 1 mg l(-1) of vancomycin and 0·5 mg l(-1) of amphotericin B, Oxoid, France) was the more efficient selective medium, with regard to the detection of Capnocytophaga species from oral samples (P < 0·001) and the elimination of commensal clinical species (P < 0·001). The demonstrated superiority of VCAT medium, related to its antibiotic content, made its use indispensable for the optimal isolation of Capnocytophaga species from polymicrobial samples. SIGNIFICANCE AND IMPACT OF THE STUDY: Isolation of Capnocytophaga species is important for the proper diagnosis and treatment of the systemic infections they cause and for epidemiological studies of periodontal flora. We showed that in pure culture, a simple blood agar allowed the growth of all Capnocytophaga species. Nonetheless, in oral samples, because of the abundance of commensal competitive flora, selective media with antibiotics are necessary for the recovery of Capnocytophaga species. The demonstrated superiority of VCAT medium made its use essential for the optimal detection of this bacterial genus. This work showed that extreme caution should be exercised when reporting the isolation of Capnocytophaga species from oral polymicrobial samples, because the culture medium is a determining factor.

Treponema denticola improves adhesive capacities of Porphyromonas gingivalis.

Porphyromonas gingivalis, an important etiological agent of periodontal disease, is frequently found associated with Treponema denticola, an anaerobic spirochete, in pathogenic biofilms. However, interactions between these two bacteria are not well understood at the molecular level. In this study, we seek to link the influence of T. denticola on the expression of P. gingivalis proteases with its capacities to adhere and to form biofilms. The P. gingivalis genes encoding Arg-gingipain A (RgpA), Lys-gingipain (Kgp), and hemagglutinin A (HagA) were more strongly expressed after incubation with T. denticola compared with P. gingivalis alone. The amounts of the three resulting proteins, all of which contain hemagglutinin adhesion domains, were increased in culture supernatants. Moreover, incubation of P. gingivalis with T. denticola promoted static and dynamic biofilm formation, primarily via a time-dependent enhancement of P. gingivalis adhesion capacities on bacterial partners such as Streptococcus gordonii. Adhesion of P. gingivalis to human cells was also increased. These results showed that interactions of P. gingivalis with other bacterial species, such as T. denticola, induce increased adhesive capacities on various substrata by hemagglutinin adhesion domain-containing proteins.

Carbonated ferric green rust as a new material for efficient phosphate removal.

Phosphate uptake from aqueous solutions by a recently discovered ferric oxyhydroxide is investigated. Carbonated ferric green rust {GR(CO(3)(2-))*} is prepared by varying two synthesis parameters, which are (1) the aging period after the ferrous-ferric green rust {GR(CO(3)(2-))} synthesis step and (2) the rate of the hydrogen peroxide addition to oxidize GR(CO(3)(2-)) into GR(CO(3)(2-))*. These two parameters permit the control of the size, morphology and cristallinity of the synthesized particles. As prepared GR* samples are then evaluated, in batch experiments, as possible low-cost efficient phosphate removal materials. Firstly, kinetic experiments reveal that a fast sorption step initially occurs and equilibrium is reached at ~500 min. The adsorption kinetics data at pH=7 can be adequately fitted to a pseudo-second order model. Secondly, the Freundlich model provides the best correlation and effectively describes phosphate sorption isotherms for all GR(CO(3)(2-))* samples synthesized. Finally, the phosphate adsorption capacity decreases when pH increases. The highest adsorption capacity is 64.8 mg g(-1) at pH=4 and corresponds to the GR(CO(3)(2-))* sample displaying the smallest and least crystallized particles thus reflecting the importance of the synthesis conditions. Overall, all sorption capacities are higher than the main iron oxide minerals, making GR(CO(3)(2-))* a potentially attractive phosphate adsorbent.

Dental abnormalities in Schimke immuno-osseous dysplasia.

Described for the first time in 1971, Schimke immuno-osseous dysplasia (SIOD) is an autosomal-recessive multisystem disorder that is caused by bi-allelic mutations of SMARCAL1, which encodes a DNA annealing helicase. To define better the dental anomalies of SIOD, we reviewed the records from SIOD patients with identified bi-allelic SMARCAL1 mutations, and we found that 66.0% had microdontia, hypodontia, or malformed deciduous and permanent molars. Immunohistochemical analyses showed expression of SMARCAL1 in all developing teeth, raising the possibility that the malformations are cell-autonomous consequences of SMARCAL1 deficiency. We also found that stimulation of cultured skin fibroblasts from SIOD patients with the tooth morphogens WNT3A, BMP4, and TGFß1 identified altered transcriptional responses, raising the hypothesis that the dental malformations arise in part from altered responses to developmental morphogens. To the best of our knowledge, this is the first systematic study of the dental anomalies associated with SIOD.

[Bacteremia of oral origin]. / Bactériémies d'origine buccale.

Transient bacteremia from oral cavity related to oral anaerobic bacteria may occur as a result of dental healthcare procedures but also as a result of daily gestures involving the gums (chewing and oral hygiene). The risk of presenting a transient bacteremia is related to oral cavity bacterial load and to the severity of inflammation in the oral cavity. Although bacteremia is transient, in patients with immunodeficiency or comorbidity, this bacteremia may cause extra-oral infections. The bacteremia rate and the identified bacteria vary from one study to the next, depending on the method used to isolate and identify bacteria. Nevertheless, the risk for bacteremia is determined by the infectious and inflammatory conditions of each patient.

Staphylococcus simulans as an authentic pathogenic agent of osteoarticular infections.

OBJECTIVES: To evaluate the role of Staphylococcus simulans in bone and joint infections (BJI) and determine their main characteristics. METHODS: A search of the database of the microbiology laboratories of Lille hospital and Tourcoing hospital was performed. Only results from blood, bone, and orthopedic device cultures were taken into account for hospitalized patients between January 2004 and January 2009. We considered cases in which S. simulans was the only bacteria isolated in all of the patients' biological samples with clinical and laboratory signs of infection. For patients with complete medical records, we recorded the clinical and epidemiological data. RESULTS: Six cases of BJI due to S. simulans were recorded, with five cases related to orthopedic devices infections. Three patients lived in rural areas. In four out of six patients, S. simulans was isolated in intraoperative biopsy material. In one patient, S. simulans grew in synovial fluid and in another in blood cultures only. The latter patient had a spondylodiscitis, and chronic foot ulcers due to gout disease were suspected to be the origin of the infection. All patients were healed after a mean follow up of 9 ± 3 months. Orthopedic devices were removed in four of the five patients concerned. The combination of rifampicin plus levofloxacin was used in four patients. CONCLUSION: The present data suggest that, even though S. simulans remains rarely observed in clinical pathology, its role in osteoarticular infections, especially in the case of infected orthopedic devices, is not exceptional. As for the antibiotic treatment, the combination of rifampicin and levofloxacin seems to be an effective strategy according to our clinical results.

CASA chromogenic medium for enteric Campylobacter species.

We prospectively assessed stool samples from 370 patients for Campylobacter species by comparing three selective agar media incubated at two temperatures: 42°C and 37°C. Twenty patients (5.4%) were found positive. The chromogenic medium CASA (AES Chemunex, France) proved highly efficient for C. jejuni and C. coli recovery, while lessening the workload in the lab.

Effect of higher minimum inhibitory concentrations of quaternary ammonium compounds in clinical E. coli isolates on antibiotic susceptibilities and clinical outcomes.

Quaternary ammonium compounds (QACs) are cationic surfactants used as preservatives and environmental disinfectants. Limited data are available regarding the effect of QACs in the clinical setting. We performed a prospective cohort study in 153 patients with Escherichia coli bacteraemia from February to September 2008 at University Hospital in Rennes. The minimum inhibitory concentrations (MICs) of antibiotics and QACs alkyldimethylbenzylammonium chloride (ADBAC) and didecyldimethylammonium chloride (DDAC) were determined by the agar dilution method. The capacity of biofilm production was assayed using the Crystal Violet method, and mutation frequencies by measuring the capacity of strains to generate resistance to rifampicin. Logistic regression analysis showed that one of the significant factors related to low MICs for ADBAC (≤16 mg/L) and DDAC (≤8 mg/L), was cotrimoxazole susceptibility (odds ratio: 3.72; 95% confidence interval: 1.22-11.24; P=0.02 and OR: 3.61; 95% CI: 1.56-7.56; P<0.01, respectively). Antibiotic susceptibility to cotrimoxazole was strongly associated with susceptibility to amoxicillin and nalidixic acid (P<0.01). Community-acquired or healthcare-associated bacteraemia, severity of bacteraemia, and patient outcome were independent of the MICs of ADBAC and DDAC. Our findings demonstrate an epidemiological relationship between higher MIC values of QACs in clinical E. coli isolates and antibiotic resistance.

Impact of surgical site infection surveillance in a neurosurgical unit.

This article describes a two-year surveillance of neurosurgical site infections and an outbreak of infections in deep brain stimulation (DBS) cases. From April to December 2008, six patients had a DBS surgical site infection (SSI). Audits of hygiene practices, infection control of the healthcare environment, and preoperative antimicrobial prophylaxis characteristics were carried out. The results of surgical audits showed that skin preparation and antimicrobial prophylaxis were not being performed adequately. In 2008, the general SSI rate was 1.8% (27 SSIs/1471 patients). Length of preoperative stay was significantly longer among infected patients (2.7 ± 2.9 months) compared with uninfected patients (2.2 ± 4.6 months) (P=0.01). Based on these results, skin preparation and antimicrobial prophylaxis were reviewed with the neurosurgery team. In 2009, the general SSI rate was reduced to 1.1% (16 SSI in 1410 patients), a reduction from 2008 (P=0.12). Although the overall incidence of SSI in 2008 (1.8%) was within the range of published data, this surveillance of SSIs permitted identification of site operative infected patients surgically treated for DBS. A set of actions was then taken to reduce SSI risk. This work demonstrates how an active surveillance programme can successfully change clinical care practice.

Inbreeding reveals stronger net selection on Drosophila melanogaster males: implications for mutation load and the fitness of sexual females.

Stronger selection on males has the potential to lower the deleterious mutation load of females, reducing the cost of sex. However, few studies have directly quantified the strength of selection for both sexes. As the magnitude of inbreeding depression (ID) is related to the strength of selection, we measured the cost of inbreeding for both males and females in a laboratory population of Drosophila melanogaster. Using a novel technique for inbreeding, we found significant ID for both juvenile viability and adult fitness in both sexes. The genetic variation responsible for this depression in fitness appeared to be recessive for adult fitness (h=0.11) and partially additive for juvenile viability (h=0.29). ID was identical across the sexes in terms of juvenile viability but was significantly more deleterious for males than females as adults, even though female X-chromosome homogamety should predispose them to a higher inbreeding load. We estimated the strength of selection on adult males to be 1.24 greater than on adult females, and this appears to be a consequence of selection arising from competition for mates. Combined with the generally positive intersexual genetic correlation for inbred lines, our results suggest that the mutation load of sexual females could be meaningfully reduced by stronger selection acting on males.

Mortality in out-of-hours emergency medical admissions--more than just a weekend effect.

Mortality among emergency medical admissions to hospital is higher for admissions at the weekend than on weekdays; this also holds true for certain specific conditions. However, it is unknown whether that effect is limited to weekends. This study calculated mortality in emergency medical admissions for each day of the week, and compared mortality at weekends with weekdays, at nights with days, and in all out-of-hours periods with in-hours in a UK district general hospital. Total mortality was increased for admissions on Mondays, at night, and in all out-of-hours periods; late in-hospital mortality (after seven days) remained increased when the initial admission occurred on Mondays, at night or out of hours. It is likely that illness severity as well as resource and organisational factors are involved.