Cetylpyridinium chloride and chlorhexidine show antiviral activity against Influenza A virus and Respiratory Syncytial virus in vitro.

BACKGROUND: The oral cavity is the site of entry and replication for many respiratory viruses. Furthermore, it is the source of droplets and aerosols that facilitate viral transmission. It is thought that appropriate oral hygiene that alters viral infectivity might reduce the spread of respiratory viruses and contribute to infection control. MATERIALS AND METHODS: Here, we analyzed the antiviral activity of cetylpyridinium chloride (CPC), chlorhexidine (CHX), and three commercial CPC and CHX-containing mouthwash preparations against the Influenza A virus and the Respiratory syncytial virus. To do so the aforementioned compounds and preparations were incubated with the Influenza A virus or with the Respiratory syncytial virus. Next, we analyzed the viability of the treated viral particles. RESULTS: Our results indicate that CPC and CHX decrease the infectivity of both the Influenza A virus and the Respiratory Syncytial virus in vitro between 90 and 99.9% depending on the concentration. Likewise, CPC and CHX-containing mouthwash preparations were up to 99.99% effective in decreasing the viral viability of both the Influenza A virus and the Respiratory syncytial virus in vitro. CONCLUSION: The use of a mouthwash containing CPC or CHX alone or in combination might represent a cost-effective measure to limit infection and spread of enveloped respiratory viruses infecting the oral cavity, aiding in reducing viral transmission. Our findings may stimulate future clinical studies to evaluate the effects of CPC and CHX in reducing viral respiratory transmissions.

Cetylpyridinium Chloride-Containing Mouthwashes Show Virucidal Activity against Herpes Simplex Virus Type 1.

The oral cavity is particularly susceptible to viral infections that are self-recovering in most cases. However, complications may appear in severe cases and/or immunocompromised subjects. Cetylpyridinium chloride (CPC)-containing mouthwashes are able to decrease the infectivity of the SARS-CoV-2 virus by disrupting the integrity of the viral envelope. Here, we show that CPC, as the active ingredient contained in commercialized, exerts significant antiviral activity against enveloped viruses, such as HSV-1, but not against non-enveloped viruses, such as HPV. CPC-containing mouthwashes have been used as antiseptics for decades, and thus, they can represent a cost-effective measure to limit infection and spread of enveloped viruses infecting the oral cavity, aiding in reducing viral transmission.

Whole Genome Sequencing and Phenotypic Analysis of Antibiotic Resistance in Filifactor alocis Isolates.

There is scarce knowledge regarding the antimicrobial resistance profile of F. alocis. Therefore, the objective of this research was to assess antimicrobial resistance in recently obtained F. alocis clinical isolates and to identify the presence of antimicrobial resistance genes. Isolates were obtained from patients with periodontal or peri-implant diseases and confirmed by sequencing their 16S rRNA gene. Confirmed isolates had their genome sequenced by whole genome sequencing and their phenotypical resistance to nine antibiotics (amoxicillin clavulanate, amoxicillin, azithromycin, clindamycin, ciprofloxacin, doxycycline, minocycline, metronidazole, and tetracycline) tested by E-test strips. Antimicrobial resistance genes were detected in six of the eight isolates analyzed, of which five carried tet(32) and one erm(B). Overall, susceptibility to the nine antibiotics tested was high except for azithromycin in the isolate that carried erm(B). Moreover, susceptibility to tetracycline, doxycycline, and minocycline was lower in those isolates that carried tet(32). The genetic surroundings of the detected genes suggested their inclusion in mobile genetic elements that might be transferrable to other bacteria. These findings suggest that, despite showing high susceptibility to several antibiotics, F. alocis might obtain new antimicrobial resistance traits due to its acceptance of mobile genetic elements with antibiotic resistance genes in their genome.

Association of nine pathobionts with periodontitis in four South American and European countries.

Aim: Our aim was to compare the prevalence and load of nine pathobionts in subgingival samples of healthy individuals and periodontitis patients from four different countries. Methods: Five hundred and seven subgingival biofilm samples were collected from healthy subjects and periodontitis patients in Belgium, Chile, Peru and Spain. The prevalence and load of Eubacterium brachy, Filifactor alocis, Fretibacterium fastidiosum, Porphyromonas endodontalis, Porphyromonas gingivalis, Selenomonas sputigena, Treponema denticola, Tannerella forsythia and Treponema socranskii were measured by quantitative PCR. Results: The association with periodontitis of all species, except for T. socranskii, was confirmed in all countries but Peru, where only P. endodontalis, P. gingivalis and T. denticola were found to be significantly associated. Moreover, most species showed higher loads at greater CAL and PPD, but not where there was BOP. Through Principal Component Analysis, samples showed clearly different distributions by diagnosis, despite observing a smaller separation in Peruvian samples. Conclusions: Unlike prevalence, relative load was found to be a reliable variable to discriminate the association of the species with periodontitis. Based on this, F. alocis, P. endodontalis, P. gingivalis, T. denticola and T. forsythia may be biomarkers of disease in Belgium, Chile and Spain, due to their significantly higher abundance in periodontitis patients.

A Mouthwash with Cetylpyridinium Chlorideis reducing salivary SARS-CoV-2 viral load in +COVID-19 / Un enjuague con Cloruro de Cetilpiridinio redujo la carga salival del virus SARSCoV-2 en pacientes con Covid-19

Aim: The aim of this randomised, double-blind, placebo-controlled pilot clinical trial is to evaluate the capacity of a mouthwash to reduce SARS-CoV-2 viral load in the saliva of patients with COVID-19. Methods: Twenty-three symptomatic SARS-CoV-2-positive outpatients were selected andrandomised into two groups and registered at NTC 04563689. Both groups rinsed and gargled for one minute with either distilled water (Placebo) or with 0.05% Cetylpyridinium chloride (CPC) plus 0.12% Chlorhexidine (CHX) mouthwash (PERIOAID Intensive Care). Saliva samples were collected before the use of placebo or mouthwash and after 15 minutes and 1 and 2 hours of either of the above treatment. A saliva sample was also taken five days after regular use of placebo or mouthwash twice daily. The virus was detected by qRT-PCR. Results: A great heterogeneity in the viral load values was observed at baseline in both groups for nasopharyngeal and saliva samples. Most of the patients who used the mouthwash (8/12) had a significant decrease in baseline viral load after 15 min (greater than 99% reduction). This inhibitory effect was maintained for up to two hours in 10 of the 12 patients. At five days, SARS-CoV-2 RNA was detectedin only 1 patient from the mouthwash group and in 5 from the placebo group. Conclusions: This study points out that a CPC mouthwash can reduce the viral load in saliva of COVID-positive patients. This finding may be important in transmission control of SARS-CoV-2. Nevertheless, the clinical relevance of CPC mouthwash-reduction on SARS-CoV-2 shedding in saliva requires further study.

Objetivo: El objetivo de este ensayo clínico piloto aleatorizado, doble ciego y controlado con placebo es evaluar la capacidad de un enjuague bucal para reducir la carga viral del SARS-CoV-2 en la saliva de pacientes con COVID-19. Materiales y métodos:Veintitrés pacientes ambulatorios positivos para SARS-CoV-2 sintomáticos fueron seleccionados y aleatorizados en dos grupos y registrados en el NTC 04563689. Ambos grupos se enjuagaron y hicieron gárgaras durante un minuto con agua destilada (placebo) o con cloruro decetilpiridinio al 0 ,05 % (CPC). ) más enjuague bucal con Clorhexidina (CHX) al 0,12% (PERIOAID Intensive Care). Se recolectaron muestras de saliva antes del uso de placebo o enjuague bucal y después de 15 minutos y 1 y 2 horas de cualquiera de los tratamientos anteriores. También se tomó una muestra de saliva cinco días después del uso regular de placebo o enjuague bucal dos veces al día. El virus fue detectado por qRT-PCR. Resultados:Se demostró una gran heterogeneidad en los valores de carga viral al inicio del estudio en grupos ambos para muestras de nasofaringe y saliva. La mayoría de los pacientes que usaron el enjuague bucal (8/12) tuvieron una disminución significativa en la carga viral inicial después de 15 minutos (reducción superior al 99 %). Este efecto inhibidor se mantuvo hasta dos horas en 10 de los 12 pacientes. A los cinco días, se detectó ARN del SARS-CoV-2 en solo 1 paciente del grupo de enjuague bucal y en 5 del grupo de placebo. Conclusiones:Este señala que un enjuague bucal CPC puedereducir la carga viral en saliva de pacientes COVID positivos. Este hallazgo puede ser importante en el control de la transmisión del SARS-CoV-2. Sin embargo, la relevancia clínica de la reducción del enjuague bucal con CPC en la excreción de SARS-CoV-2 en la saliva requiere más estudios.

Microbial profile of placentas from Tanzanian mothers with adverse pregnancy outcomes and periodontitis.

AIM: To investigate microbial profiles in placentas from a population of East African mothers with and without adverse pregnancy outcomes and with regard to their periodontal status. MATERIAL AND METHODS: Thirty-six placentas from pregnant women from Tanzania were classified into three groups according to both pregnancy outcome and the mother's periodontal health. The microbial composition in each group was then compared using 16S rRNA metagenomics. Additionally, placenta specimens were analyzed histologically for chorioamnionitis by a single pathologist blinded to the clinical data. RESULTS: The greatest differences were observed in the group of mothers with periodontitis. The microbial load was low in all three groups of mothers. Periodontitis had a notable influence on the structure of the placental microbiota. Three phyla and 44 genera were associated with periodontitis, whereas only the Tenericutes phylum was associated with the adverse pregnancy variable. Streptococcaceae and Mycoplasmataceae families were associated with both periodontitis and adverse pregnancy outcomes. Finally, although the differences for chorioamnionitis were not significant, this intra-amniotic infection was more frequent in the placentas from mothers with periodontitis. CONCLUSIONS: Our findings suggest that bacteria from the oral cavity may involve the feto-placental unit, and that periodontitis may be a modulating factor of the microbial community present in this niche.

Bacterial decontamination of toothbrushes by immersion in a mouthwash containing 0.05% chlorhexidine and 0.05% cetylpyridinium chloride: A randomized controlled trial.

OBJECTIVE: Toothbrushes are colonized by microorganisms, implying a risk of infection. That risk can be reduced by decreasing the microbial contamination of the filaments. Therefore, this study aimed to determine the antiseptic efficacy of a 0.05% chlorhexidine + 0.05% cetylpyridinium chloride mouthwash on toothbrushes. METHODS: A total of twelve toothbrushes used three times/day for 14 days by orally and systemically healthy people were randomly split into two groups, and their heads were immersed for 2 h in PBS (control) or Perio·Aid Active Control (treatment). The microorganisms were recovered, and their number was calculated by culture, quantitative PCR, and viability PCR. Statistical differences were first assessed with a two-way mixed ANOVA and subsequently with Student's t-test. RESULTS: The results showed no statistical differences in the total number of cells for the treatment (mean ± CI95% of 7.27 ± 1.09 log10 bacteria/ml) and the control (7.62 ± 0.64 log10 bacteria/ml) groups, but a significantly lower number of live cells in the treatment group (4.58 ± 0.61 log10 viable bacteria/ml and 2.15 ± 1.42 log10 cfu/ml) than in the control group (6.49 ± 1.39 log10 viable bacteria/ml and 5.04 ± 0.93 log10 cfu/ml). CONCLUSIONS: Based on our findings, sanitization of toothbrushes with this mouthwash reduces the number of live microorganisms adhered to the filaments. Such decrease of the bacterial load could include bacteria from the oral cavity, from the environment, and from nearby toothbrushes since the quantification was not limited to any bacterial taxon.

Randomized clinical trial to assess the impact of oral intervention with cetylpyridinium chloride to reduce salivary SARS-CoV-2 viral load.

AIM: Aerosols released from the oral cavity help spread the SARS-CoV-2 virus. The use of a mouthwash formulated with an antiviral agent could reduce the viral load in saliva, helping to lower the spread of the virus. The aim of this study was to assess the efficacy of a mouthwash with 0.07% cetylpyridinium chloride (CPC) to reduce the viral load in the saliva of Coronavirus disease 2019 (COVID-19) patients. MATERIALS AND METHODS: In this multi-centre, single-blind, randomized, parallel group clinical trial, 80 COVID-19 patients were enrolled and randomized to two groups, namely test (n = 40) and placebo (n = 40). Saliva samples were collected at baseline and 2 h after rinsing. The samples were analysed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and an enzyme-linked immunosorbent assay test specific for the nucleocapsid (N) protein of SARS-CoV-2. RESULTS: With RT-qPCR, no significant differences were observed between the placebo group and the test group. However, 2 h after a single rinse, N protein concentration in saliva was significantly higher in the test group, indicating an increase in lysed virus. CONCLUSIONS: The use of 0.07% CPC mouthwash induced a significant increase in N protein detection in the saliva of COVID-19 patients. Lysis of the virus in the mouth could help reduce the transmission of SARS-CoV-2. However, more studies are required to prove this.

Cetylpyridinium chloride promotes disaggregation of SARS-CoV-2 virus-like particles.

BACKGROUND: SARS-CoV-2 is continuously disseminating worldwide. The development of strategies to break transmission is mandatory. AIM OF THE STUDY: To investigate the potential of cetylpyridinium chloride (CPC) as a viral inhibitor. METHODS: SARS-CoV-2 Virus Like-Particles (VLPs) were incubated with CPC, a potent surfactant routinely included in mouthwash preparations. RESULTS: Concentrations of 0.05% CPC (w/v) commonly used in mouthwash preparations are sufficient to promote the rupture of SARS-CoV-2 VLP membranes. CONCLUSION: Including CPC in mouthwashes could be a prophylactic strategy to keep SARS-CoV-2 from spreading.

Erythritol-enriched powder and oral biofilm regrowth on dental implants: an in vitro study / Polvo enriquecido con eritritol y crecimiento de biopelículas orales sobre implantes dentales: un estudio in vitro

Backgroud: Peri-implant mucositis and peri-implantitis are the main biological complications associated withdental implants. Since most authors agree that bacteria play a major etiological role, the main aims of this studywere to determine if a formulation of erythritol and chlorhexidine applied with an air polishing system inhibitsbiofilm re-growth over dental implants and to compare the decontamination capacity of this therapy with that ofmechanical removal by saline and gauze.Material and Methods: A multispecies biofilm (P. gingivalis, A. actinomycetemcomitans, F. nucleatum, A. naes-lundii, V. parvula and S. oralis) was grown for 14 days on 52 dental implants in an artificial mouth. These implantswere divided into three groups according to the applied treatment: 14 negative control (CON), 19 erythritol-chlorhexidine (ERY) and 19 gauze with saline (GAU) samples. Twelve dental implants from the ERY and GAUgroups and 8 implants from the CON group were re-incubated for 7 additional days after treatment. The bacterialcount was performed by quantitative polymerase chain reaction (qPCR) using propidium monoazide (PMA). Adescriptive and bivariate analysis of the data was performed.Results: The erythritol and chlorhexidine formulation significantly inhibited biofilm regrowth in comparison withthe mechanical treatment (GAU), since a significant decrease in all the species was observed in the ERY group(except for Aggregatibacter actinomycetemcomitans). The antibiofilm and antibacterial capacity of the two activetreatment groups (ERY and GAU) was similar for a 14 days multispecies in vitro biofilm, except for the lowercount of A. naeslundii in the GAU group. Conclusions: The use of erythritol powder with chlorhexidine applied with an air polishing system reduces biofilmregrowth over dental implants when compared with mechanical removal by saline and gauze. This effect might bebeneficial for patients included in peri-implant maintenance programs.(AU)

Greater fuel efficiency is potentially preferable to reducing NOx emissions for aviation's climate impacts.

Aviation emissions of nitrogen oxides (NOx) alter the composition of the atmosphere, perturbing the greenhouse gases ozone and methane, resulting in positive and negative radiative forcing effects, respectively. In 1981, the International Civil Aviation Organization adopted a first certification standard for the regulation of aircraft engine NOx emissions with subsequent increases in stringency in 1992, 1998, 2004 and 2010 to offset the growth of the environmental impact of air transport, the main motivation being to improve local air quality with the assumed co-benefit of reducing NOx emissions at altitude and therefore their climate impacts. Increased stringency is an ongoing topic of discussion and more stringent standards are usually associated with their beneficial environmental impact. Here we show that this is not necessarily the right direction with respect to reducing the climate impacts of aviation (as opposed to local air quality impacts) because of the tradeoff effects between reducing NOx emissions and increased fuel usage, along with a revised understanding of the radiative forcing effects of methane. Moreover, the predicted lower surface air pollution levels in the future will be beneficial for reducing the climate impact of aviation NOx emissions. Thus, further efforts leading to greater fuel efficiency, and therefore lower CO2 emissions, may be preferable to reducing NOx emissions in terms of aviation's climate impacts.

Resistance to ß-lactams and distribution of ß-lactam resistance genes in subgingival microbiota from Spanish patients with periodontitis.

OBJECTIVES: The aim of this study was to analyze the distribution of ß-lactamase genes and the multidrug resistance profiles in ß-lactam-resistant subgingival bacteria from patients with periodontitis. MATERIALS AND METHODS: Subgingival samples were obtained from 130 Spanish patients with generalized periodontitis stage III or IV. Samples were grown on agar plates with amoxicillin or cefotaxime and incubated in anaerobic and microaerophilic conditions. Isolates were identified to the species level by the sequencing of their 16S rRNA gene. A screening for the following ß-lactamase genes was performed by the polymerase chain reaction (PCR) technique: blaTEM, blaSHV, blaCTX-M, blaCfxA, blaCepA, blaCblA, and blaampC. Additionally, multidrug resistance to tetracycline, chloramphenicol, streptomycin, erythromycin, and kanamycin was assessed, growing the isolates on agar plates with breakpoint concentrations of each antimicrobial. RESULTS: ß-lactam-resistant isolates were found in 83% of the patients. Seven hundred and thirty-seven isolates from 35 different genera were obtained, with Prevotella and Streptococcus being the most identified genera. blaCfxA was the gene most detected, being observed in 24.8% of the isolates, followed by blaTEM (12.9%). Most of the isolates (81.3%) were multidrug-resistant. CONCLUSIONS: This study shows that ß-lactam resistance is widespread among Spanish patients with periodontitis. Furthermore, it suggests that the subgingival commensal microbiota might be a reservoir of multidrug resistance and ß-lactamase genes. CLINICAL RELEVANCE: Most of the samples yielded ß-lactam-resistant isolates, and 4 different groups of bla genes were detected among the isolates. Most of the isolates were also multidrug-resistant. The results show that, although ß-lactams may still be effective, their future might be hindered by the presence of ß-lactam-resistant bacteria and the presence of transferable bla genes.

Tetracycline and multidrug resistance in the oral microbiota: differences between healthy subjects and patients with periodontitis in Spain.

Introduction: Antibiotic resistance is widely found even among bacterial populations not having been exposed to selective pressure by antibiotics, such as tetracycline. In this study we analyzed the tetracycline-resistant subgingival microbiota of healthy subjects and of patients with periodontitis, comparing the prevalence of tet genes and their multidrug resistance profiles. Methods: Samples from 259 volunteers were analyzed, obtaining 813 tetracycline-resistant isolates. The prevalence of 12 antibiotic resistance genes was assessed, and multidrug profiles were built. Each isolate was identified by 16S rRNA sequencing. Differences in qualitative data and quantitative data were evaluated using the chi-square test and the Mann-Whitney-U test, respectively. Results: tet(M) was the most frequently detected tet gene (52.03%). We observed significant differences between the prevalence of tet(M), tet(W), tet(O), tet(32) and tet(L) in both populations studied. Multidrug resistance was largely observed, with resistance to kanamycin being the most detected (83.64%). There were significant differences between the populations in the prevalence of kanamycin, chloramphenicol, and cefotaxime resistance. Resistant isolates showed significantly different prevalence between the two studied groups. Conclusion: The high prevalence of multidrug resistance and tetracycline resistance genes found in the subgingival microbiota, highlights the importance of performing wider and more in-depth analysis of antibiotic resistance in the oral microbiota.

Detection and expression analysis of tet(B) in Streptococcus oralis.

Tetracycline resistance can be achieved through tet genes, which code for efflux pumps, ribosomal protection proteins and inactivation enzymes. Some of these genes have only been described in either Gram-positive or Gram-negative bacteria. This is the case of tet(B), which codes for an efflux pump and, so far, had only been found in Gram-negative bacteria. In this study, tet(B) was detected in two clinical Streptococcus oralis strains isolated from the gingival sulci of two subjects. In both cases, the gene was completely sequenced, yielding 100% shared identity and coverage with other previously published sequences of tet(B). Moreover, we studied the expression of tet(B) using RT-qPCR in the isolates grown with and without tetracycline, detecting constitutive expression in only one of the isolates, with no signs of expression in the other one. This is the first time that the presence and expression of the tet(B) gene has been confirmed in Gram-positive bacteria, which highlights the potential of the genus Streptococcus to become a reservoir and a disseminator of antibiotic resistance genes in an environment so prone to horizontal gene transfer as is the oral biofilm.

Development and viability of biofilms grown on experimental abutments mimicking dental implants: An in vivo model

Background: To determine whether an experimental abutment mimicking the macro- and microstructure of a dental implant is a suitable method for recovering biofilm, and to describe the features of biofilms formed around such abutments on healthy implants. Material and Methods: Experimental abutments were used in 15 patients without peri-implant diseases. After 14 days' absence of dental hygiene in this area, the abutments were retrieved and analyzed through confocal laser scanning microscopy and scanning electron microscopy. The biofilm formation on the surface of the first 5 abut-ments was determined by a fluorescence-staining method using SYTO9 nucleic acid stain. In order to study the biofilm's coverage and vitality, 10 additional abutments were assessed using live & dead bacterial viability. Descriptive and bivariate analyses of the data were performed. Results: A global plaque coverage of the abutments was observed in all cases. The submucosal area of the abutment was mostly covered with biofilm (over 21%). Moreover, significant differences between supra- and subgingival locations were detected. Conclusions: This in vivo experimental model allows detailed observation of the extensive plaque growth found on exposed experimental abutments mimicking dental implants when hygiene measures are absent. The biofilm cover-age is significantly higher in the supragingival zone than in the subgingival portion

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Azithromycin and erythromycin susceptibility and macrolide resistance genes in Prevotella from patients with periodontal disease.

OBJECTIVES: To study oral Prevotella spp. isolated from patients with chronic periodontitis, to determine their susceptibility to azithromycin and erythromycin and to screen the presence of macrolide resistance genes therein. MATERIAL AND METHODS: Isolates with a Prevotella-like morphology were obtained from subgingival samples of 52 patients with chronic periodontitis. Each isolate was identified to the species level by sequencing of the 16S rRNA gene. In 100 Prevotella spp. isolates, azithromycin and erythromycin susceptibility was determined using the E test method, and the screening of erm(A), erm(B), erm(C), erm(F), erm(G), erm(Q) and mef(A) genes was done by PCR. RESULTS: Prevotella intermedia and Prevotella nigrescens were the most identified species (33% each). Minimum inhibitory concentrations (MICs) ranges for both antibiotics were 0.016/0.032 to >256 µg/ml. MIC50 values for azithromycin and erythromycin were 1.5 and 1 µg/ml, respectively, and MIC90 values were >256 µg/ml for both antibiotics. Nineteen per cent of the isolates carried erm(B), and 51% carried erm(F). CONCLUSIONS: The MIC values found were high compared to previous studies. erm(F) was greatly prevalent, and we describe for the first time the erm(B) gene in Prevotella spp. The presence of either of the genes seems to be associated with a higher degree of resistance to azithromycin and erythromycin.

Trading off Aircraft Fuel Burn and NO x Emissions for Optimal Climate Policy.

Aviation emits pollutants that affect the climate, including CO2 and NO x, NO x indirectly so, through the formation of tropospheric ozone and reduction of ambient methane. To improve the fuel performance of engines, combustor temperatures and pressures often increase, increasing NO x emissions. Conversely, combustor modifications to reduce NO x may increase CO2. Hence, a technology trade-off exists, which also translates to a trade-off between short-lived climate forcers and a long-lived greenhouse gas, CO2. Moreover, the NO x-O3-CH4 system responds in a nonlinear manner, according to both aviation emissions and background NO x. A simple climate model was modified to incorporate nonlinearities parametrized from a complex chemistry model. Case studies showed that for a scenario of a 20% reduction in NO x emissions the consequential CO2 penalty of 2% actually increased the total radiative forcing (RF). For a 2% fuel penalty, NO x emissions needed to be reduced by >43% to realize an overall benefit. Conversely, to ensure that the fuel penalty for a 20% NO x emission reduction did not increase overall forcing, a 0.5% increase in CO2 was found to be the "break even" point. The time scales of the climate effects of NO x and CO2 are quite different, necessitating careful analysis of proposed emissions trade-offs.

Association of periodontitis with preterm birth and low birth weight: a comprehensive review.

It is estimated that six million perinatal deaths occur every year worldwide, with premature birth being the main cause. Scientific evidence has shown that there is an association between periodontal health during pregnancy and adverse outcomes of labor, although interventional studies based on the treatment of periodontitis have failed to document an impact on reducing the incidence of preterm birth (PB) or low birth weight (LBW). Two pathogenic mechanisms have been proposed to explain this association. The direct pathway is based on the presence of gram-negative anaerobic bacteremia originating in the gingival biofilm, whereas the indirect pathway involves the production of pro-inflammatory markers which enter the bloodstream from the gingival submucosa. The result is the same: the development of an immune inflammatory response and/or the local suppression of growth factors in the fetal-placental unit, which in turn triggers labor. In the present review, we describe current concepts pertinent to PB and LBW, chronic and aggressive periodontitis, and the most frequent aspects of periodontal pathology during pregnancy. We evaluate the scientific evidence available to date, and offer a detailed description of the two pathways proposed to explain the association of maternal periodontitis with preterm and LBW delivery.

Periodontal pathogens and tetracycline resistance genes in subgingival biofilm of periodontally healthy and diseased Dominican adults.

OBJECTIVE: The objective of this study was to compare the periodontopathogen prevalence and tetracycline resistance genes in Dominican patients with different periodontal conditions. METHODS: Seventy-seven samples were collected from healthy, gingivitis, chronic (CP) and aggressive (AgP) periodontitis patients. Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Prevotella intermedia, Parvimonas micra, Eikenella corrodens and Dialister pneumosintes and 11 resistance genes were studied by PCR. P. gingivalis fimA genotype was determined. RESULTS: In healthy patients, P. micra and P. intermedia were the most and least frequently detected, respectively. T. forsythia and E. corrodens appeared in 100% of gingivitis patients. Red complex, D. pneumosintes and E. corrodens were significantly more prevalent in CP compared to healthy patients. F. nucleatum and T. denticola were detected more frequently in AgP. A. actinomycetemcomitans was the most rarely observed in all groups. The fimA II genotype was the most prevalent in periodontitis patients. Seven tetracycline-resistant genes were detected. tet(Q), tet(32) and tet(W) showed the greatest prevalence. tet(32) was significantly more prevalent in CP than in healthy patients. CONCLUSIONS: Red complex bacteria and D. pneumosintes were significantly the most prevalent species among periodontitis patients. T. forsythia was the most frequently detected in this population. To our knowledge, this is the first study describing the tet(32) gene in subgingival biofilm from healthy and periodontally diseased subjects. CLINICAL RELEVANCE: This study contributes to the knowledge on the subgingival microbiota and its resistance genes of a scarcely studied world region. Knowing the prevalence of resistance genes could impact on their clinical prescription and could raise awareness to the appropriate use of antibiotics.

Characterization and serotype distribution of Aggregatibacter actinomycetemcomitans isolated from a population of periodontitis patients in Spain.

OBJECTIVE: There is no study characterizing the variability of Aggregatibacter actinomycetemcomitans isolates in periodontitis patients in Spain. It is therefore the aim of this investigation to study the serotype distribution of A. actinomycetemcomitans strains isolated from periodontitis patients in Spain. The polymorphism of the genes that codifies the leukotoxin and the operon of the cytolethal-distending toxin (cdt) will also be investigated. DESIGN: From a total of 701 patients samples, 40 A. actinomycetemcomitans-positive periodontitis patients were included in the study (mean age 45.3, 62.5% females) and their clinical periodontal status was assessed. On average, 1-3 isolates from each patient were sub-cultured and characterized by PCR. RESULTS: Using culture the prevalence of A. actinomycetemcomitans was 5.7%. The most frequent serotype was "b", being 30 patients infected by a unique serotype, while 7 patients showed co-colonization, mostly with serotypes "a" and "b". From the 79 pure isolates obtained, 24 were from serotype "a", 30 from serotype "b", 12 from serotype "c" and 4 from serotype "d". Further characterization of these samples showed that none of these 79 isolates demonstrated the 530-bp deletion in the leukotoxin's promoter region that characterizes the JP2 strain. Conversely 65.8% of the isolates were cdt+. CONCLUSIONS: The most common serotypes were "a" and "b", being serotype "b" the most prevalent in mono-colonization, while serotypes "e" and "f" were not detected. In the majority of samples, operon that codifies the cdt (65.8%) and the genes responsible for the codification of leukotoxin (100%) were found. None of the isolates were JP2 strains.