Efeito da doxiciclina e da minociclina em células osteoblásticas humanas: estudos in vitro

A doxiciclina e a minociclina são antibióticos utilizados para eliminar infecções que surgem após o processo cirúrgico e que parecem exercer uma acção benéfica sobre o metabolismo ósseo. Os resultados obtidos neste estudo mostraram que baixas concentrações destes fármacos(1-5 μg.ml-1) estimularam a proliferação das células de medula óssea humana. A exposição das células a 10 μg.ml-1 de minociclina pareceu estimular o aparecimento de uma população celular mais proliferativa mas menos diferenciada. As concentrações de 10 μg.ml-1 de doxiciclina e 25 μg.ml-1 de minociclina atrasaram a mineralização e concentrações mais elevadas destes antibióticos (25 μg.ml-1 de doxiciclina e 50 μg.ml-1 de minociclina) foram citotóxicas. Doxycycline and minocycline are antibiotics used to eliminate infections that arise after the surgical procedure that seem to have a beneficial action in bone metabolism. Results showed that low concentrations of these drugs (1-5 μg.ml-1) stimulated human bone marrow cell proliferation. The exposure of cells to 10 μg.ml-1 minocycline stimulated the emergence of a more proliferative population but less differentiated. Concentrations of 10 μg.ml-1 doxycycline and 25 μg.ml-1 minocycline delayed the mineralization and higher concentrations of these antibiotics (25 μg.ml-1 doxycycline and 50 μg.ml-1 minocycline) were cytotoxic

The effects of tigecycline on human osteoblasts in vitro

A osteomielite, infecção no tecido ósseo, é uma doença que afecta gravemente os pacientes, uma vez que destrói grandes quantidades de tecido ósseo. A tigeciclina é um antibiótico recentemente disponível, que pode proporcionar melhores resultados no combate a infecções ósseas por organismos resistentes a outros antibióticos. Não existem na bibliografia dados disponíveis sobre a interacção da tigeciclina com as células ósseas. Neste trabalho foi demonstrado que a tigeciclina em elevadas concentrações tem efeitos nocivos para o tecido ósseo nomeadamente na proliferação dos osteoblastos. Esta informação deve ser ponderada na aplicação de dispositivos de aplicação local do antibiótico. Em baixas concentrações este fenómeno não foi verificado. Osteomyelitis (bone tissue infection), is a very serious disease affecting many patients by destroying large portions of bone tissue. Tigecycline is a recently available antibiotic to overcome bacteria resistance phenomena in bone tissue infections. No information is available regarding its direct effects on bone cells. We have demonstrated deleterious effects of high tigecycline concentrations on viability and proliferation of osteoblasts in vitro. This finding should be carefully taken into account when a local antibiotic application is used. However, at lower concentrations tigecycline this effect was not observed

Oral microbiome associated with peri-implant infections – a review

Dental treatments using dental implants have been well documented over the past 40 years and with great success. The dental implant installed in the place of missing teeth should always involve proper forecasting by the dentist. Namely, it is important to know the microbiome surrounding the implant, from its planning till final rehabilitation. The exact time of microbiome formation, as well as microorganisms involved, are essential for the proper implementation and success of the implant. However, internal contaminations of the rehabilitated implants, the extracellular components of microorganisms, such as endotoxins, have a huge influence on implant success. In addition, it is also very important the knowledge concerning implants surfaces and associated microorganisms. This study conducted a literature review on the oral microbiome and its relationship with the peri-implant infection, with the discussion of several classical and current studies. Although it can be concluded that the peri-implant microbiome is characterized by the microbiome present before dental implant placing, more studies are required to better elucidate the planning and the longevity of dental implant treatment.info:eu-repo/semantics/publishedVersio

Nasal carriage of Staphylococcus aureus among nursing students during curricular internship

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Microorganisms: the reason to perform endodontics

That we perform Endodontics because there are microorganisms is now beyond doubt. Nevertheless, not only the microorganisms, but also the host response have a profound effect on the progression of the disease. Many papers confirmed the polymicrobial nature of pulpal and periapical diseases of endodontic origin and the efficiency of the chemo-mechanical procedures based on physical and chemical elimination of their etiologic factors, whose principles were first presented as far as 1928 by Hall. Since not only bacterial load may be related to the clinical outcome, but also the bacterial composition of the microbiological canal ecosystem, we aimed at the enumeration of the microorganisms present in the different types of endodontic infections. Although the emerging picture is clearly a complex one, not allowing clear-cut association of bacteria and clinical situation, only the further pursuit of elucidation of the many factors involved (including geographical variability) will ultimately lead to rational treatment solutions.info:eu-repo/semantics/publishedVersio

Prevalence of antibiotic (ß-lactams, tetracycline, metronidazole, erythromycin) resistance genes in periodontic infections

Objective: Porphyromonas gingivalis and Prevotella intermedia are thought to be pathogens in adult periodontitis. Antibiotherapy is usually needed in the treatment of periodontitis being often prescribed empirically. To allow prescription of a specific antibiotic treatment, identification of resistance genes should be performed. The aim of this study was the identification of the presence of TetM, TetQ, TEM, cfxA, MefA, ErmB and Nim resistance genes in previously identified P. intermedia and P. gingivalis isolated from samples collected from periodontal infections. Method: PCR was used for the identification of TetM, TetQ, TEM, cfxA, MefA, ErmB and Nim resistance genes in strains isolated from samples collected from periodontal infections. Results: It was seen that 8% of isolates had one of the tested tetracycline resistance genes. A total of 32% of β-lactamases resistance genes was observed in isolated strains. It was also observed that 2% of isolates had one of the analysed erythromycin resistance genes. None of the isolates showed the presence of the metronidazole resistance gene. Conclusions: Most strains harboring β-lactamase resistance genes had been previously identified as P. intermedia. No tetracycline resistance gene and a very low percentage of β-lactamase resistance genes were observed in P. gingivalis strains.info:eu-repo/semantics/publishedVersio

Identification of TEM, CfxA, TetM and TetQ genes in periodontic infections

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Cerium and gentamicin antibacterial activity on loaded calcium-phosphates microspheres

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Identification of yeast and non-pigmented cultivable endodontic bacteria in adult portuguese patients

Introduction This study has focused on the identification of the yeasts and non-pigmented bacteria present on adult patients with necrosis or apical periodontitis and the ones who resisted chemomechanical preparation and intracanal dressing with calcium hydroxide paste (Ca(OH)2) or 2% chlorohexidine digluconate gel (CHX). Methods 69 single-rooted teeth of adult patients with necrosis associated or not with apical periodontitis were selected (strict inclusion criteria); CHX group: 34 teeth; Ca(OH)2 group: 35 teeth. Bacteria samples were taken at baseline (S1), after chemo-mechanical preparation (S2) and after 14 days of intracanal dressing (S3). Bacteria and fungal presence was evaluate by means of culture in three atmospheres (aerobic, anaerobic, microaerofilic) in appropriate culture broads. Strict techniques were used for serial dilution, plating, incubation and identification. Results The most represented, abundant and prevalent strains of non-pigmented bacteria were Propionibacterium acnes (detected in S1, S2 and S3), Gemella morbillorum and Clostridium difficile. Candida albicans was found in 9 patients. The higher number of isolates proceeded from S1, being S2 the moment with lowest number of isolates. CHX had a worst performance in disinfection of the root canal system; consequently the number of isolates from S3 samples was bigger compared to Ca(OH)2. The number of identified bacterial species per canal/moment of sampling, varied from zero till 5, including yeasts (Candida albicans). Conclusions: Our findings confirm that the microbiota from primary endodontic infections is polymicrobial, and the anaerobes Gram-positive non-pigmented bacteria are well represented. CHX performed worse, consequently the number of isolates from S3 samples was bigger when compared to Ca(OH)2 as well as with diagnosis of necrosis.info:eu-repo/semantics/publishedVersio

Bacterial contamination of gutta-percha points from different brands and the efficacy of a chairside disinfection protocol

Objective: To evaluate the bacterial contamination of different brands of Gutta-Percha (GP) points routinely used in clinical practice and the efficacy of a chairside disinfection protocol with sodium hypochlorite. Methods: GP points (n=240), in sizes A, B, C, D, K15, K20, K25, K30, K35, K40, F1, F2, F3 (Dentsply®, Proclinic®, ProTaper® and R&S®), were randomly sampled from commercial packages already in use. These were added directly to Fluid Thioglycolate Medium (one GP point per tube) and incubated at 37ºC for 21 days. During this period, the presence/absence of turbidity was evaluated. To evaluate the efficacy of a chairside disinfection protocol, all detected contaminated GP points were immersed for 1 minute in 10 mL of 5.25% sodium hypochlorite, followed by 5 minutes in 10 mL of detergent solution (3% Tween 80 and 5% sodium thiosulfate) and a final rinse with 10 mL of sterile distilled water and incubated. The data was analysed using the chi-square test and differences between characteristics of dichotomic variables were performed using the binomial test. The significance level was set at P<0.05. Results: Bacterial growth was observed in 22.9% of the total study samples. Dentsply® and R&S® showed the highest level of contamination, 47.3% each, although without significant differences to the other commercial brands. The most contaminated GP point size was K30 (16.4%). The chairside disinfection protocol was effective in disinfection of 76.4% of GP points (P<0.001). Conclusion: A real small number of GP points in clinical use harboured bacteria, including after the Chairside Disinfection Protocol that, anyway, proved to be effective. No significant difference was observed between tested commercial brands.info:eu-repo/semantics/publishedVersio