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BACKGROUND: Bacteroides fragilis group (BFG) species are the most significant anaerobic pathogens and are also the most antibiotic-resistant anaerobic species. Therefore, surveying their antimicrobial resistance levels and investigating their antibiotic resistance mechanisms is recommended. Since their infections are endogenous and they are important constituents of the intestinal microbiota, the properties of the intestinal strains are also important to follow. The aim of this study was to investigate the main antibiotic gene content of microbiota isolates from healthy people and compare them with the gene carriage of strains isolated from infections. RESULTS: We detected 13, mainly antibiotic resistance determinants of 184 intestinal BFG strains that were isolated in 5 European countries (Belgium, Germany, Hungary, Slovenia and Turkey) and compared these with values obtained earlier for European clinical strains. Differences were found between the values of this study and an earlier one for antibiotic resistance genes that are considered to be mobile, with higher degrees for cfxA, erm(F) and tet(Q) and with lower degrees for msrSA, erm(B) and erm(G). In addition, a different gene prevalence was found depending on the taxonomical groups, e.g., B. fragilis and NBFB. Some strains with both the cepA and cfiA ß-lactamase genes were also detected, which is thought to be exceptional since until now, the B. fragilis genetic divisions were defined by the mutual exclusion of these two genes. CONCLUSIONS: Our study detected the prevalences of a series of antibiotic resistance genes in intestinal Bacteroides strains which is a novelty. In addition, based on the current and some previous data we hypothesized that prevalence of some antibiotic resistance genes detected in the clinical and intestinal BFG strains were different, which could be accounted with the differential composition of the Bacteroides microbiota and/or the MGE mobilities at the luminal vs. mucosal sites of the intestine.
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Antibacterianos , Infecções por Bacteroides , Bacteroides , Carbapenêmicos , Humanos , Europa (Continente) , Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , Infecções por Bacteroides/microbiologia , Bacteroides/genética , Bacteroides/efeitos dos fármacos , Bacteroides/isolamento & purificação , Farmacorresistência Bacteriana/genética , Microbioma Gastrointestinal/efeitos dos fármacos , Microbioma Gastrointestinal/genética , Testes de Sensibilidade Microbiana , Genes Bacterianos/genética , Intestinos/microbiologia , Proteínas de Bactérias/genéticaRESUMO
Here, we sought to assess the levels of antibiotic resistance among intestinal Bacteroides and Parabacteroides strains collected between 2014 and 2016 in Europe and also attempted to compare resistance levels between clinical and commensal isolates. Bacteroides and Parabacteroides isolates were recovered from faecal samples via the novel Bacteroides Chromogenic Agar (BCA) method. Antibiotic susceptibilities were determined by agar dilution for ten antibiotics. The values obtained were then statistically evaluated. Altogether 202 Bacteroides/Parabacteroides isolates (of which 24, 11.9%, were B. fragilis) were isolated from the faecal specimens of individuals taken from five European countries. The percentage values of isolates resistant to ampicillin, amoxicillin/clavulanate, cefoxitin, imipenem, clindamycin, moxifloxacin, metronidazole, tetracycline, tigecycline and chloramphenicol were 96.6, 4.5, 14.9, 2.0, 47.3, 11.4, 0, 66.2, 1.5 and 0%, respectively. These values are close to those reported in the previous European clinical Bacteroides antibiotic susceptibility survey except for amoxicillin/clavulanate and clindamycin, where the former was lower and the latter was higher in normal microbiota isolates. To account for these latter findings and to assess temporal effects we compared the data specific for Hungary for the same period (2014-2016), and we found differences in the resistance rates for cefoxitin, moxifloxacin and tetracycline.
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Antibacterianos/farmacologia , Bacteroides/efeitos dos fármacos , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Bacteroides/genética , Infecções por Bacteroides/epidemiologia , Infecções por Bacteroides/microbiologia , Europa (Continente)/epidemiologia , Voluntários Saudáveis , Humanos , Testes de Sensibilidade Microbiana , RNA Ribossômico 16SRESUMO
OBJECTIVE: The aim of this study was to investigate the characteristics of bacteremia caused by professional mechanical plaque removal (PMPR) in two groups of patients with generalized moderate chronic periodontitis. MATERIALS AND METHODS: Venous blood samples were taken at multiple time points for one hour following PMPR in fifty patients with generalized moderate chronic periodontitis. Subjects consisted of two groups, one group was receiving supportive periodontal therapy (SPT, n = 25) and the other group was receiving initial periodontal therapy (IPT, n = 25). Blood samples were processed and analyzed for cultivable microflora. Pertinent clinical parameters were recorded for each patient in both groups. RESULTS: Bacteremia was detected in 10 of 25 SPT and 8 of 25 IPT patients (p = 0.796). In both groups, the prevalence of bacteremia was dependent on the time of blood sampling and varied in magnitude between <102 CFU/ml and 106 CFU/ml. Sixteen different bacterial species were identified in both groups, mostly Actinomyces naeslundii (SPT n = 3, IPT n = 4) and Streptococcus spp. (SPT n = 6, IPT n = 2). In regression models, Grade II furcation involvement (p = 0.004) and Gingival Bleeding Index (p = 0.036) had affected the occurrence of bacteremia but in the SPT group only. CONCLUSION: Professional mechanical plaque removal was associated with bacteremia regardless of whether a patient was receiving SPT or IPT.
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Bacteriemia/epidemiologia , Periodontite Crônica/microbiologia , Placa Dentária/microbiologia , Inflamação/microbiologia , Higiene Bucal , Adulto , Idoso , Feminino , Alemanha/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , PrevalênciaRESUMO
PURPOSE: The oral microbiome has been related to numerous extra oral diseases. Recent studies detected a high abundance of oral bacteria in inflamed appendices in pediatric patients. To elucidate the role of oral bacteria in acute pediatric appendicitis, we studied the oral and appendiceal microbiome of affected children compared to healthy controls. METHODS: Between January and June 2015, 21 children undergoing appendectomy for acute appendicitis and 28 healthy controls were prospectively enrolled in the study. All individuals underwent thorough dental examination and laboratory for inflammatory parameters. Samples of inflamed appendices and the gingival sulcus were taken for 16S rDNA sequencing. RT-qPCR of Fusobacterium nucleatum, Peptostreptococcus stomatis, and Eikenella corrodens was performed and their viability was tested under acidic conditions to mimic gastric transfer. RESULTS: In phlegmonous appendices, Bacteroidetes and Porphyromonas were discovered as dominant phylum and genus. In sulcus samples, Firmicutes and Streptococcus were detected predominantly. P. stomatis, E. corrodens, and F. nucleatum were identified in each group. Viable amounts of P. stomatis were increased in sulci of children with acute appendicitis compared to sulci of healthy controls. In inflamed appendices, viable amounts of E. corrodens and F. nucleatum were decreased compared to sulci of children with appendicitis. Postprandial viability could be demonstrated for all tested bacteria. CONCLUSION: In children with acute appendicitis, we identified several oral bacterial pathogens. Based on postprandial viability of selected species, a viable migration from the oral cavity through the stomach to the appendix seems possible. Thus, the oral cavity could be a relevant reservoir for acute appendicitis.
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Apendicite/microbiologia , Microbiota , Mucosa Bucal/microbiologia , Doença Aguda , Criança , Feminino , Humanos , Concentração de Íons de Hidrogênio , Masculino , Viabilidade Microbiana , Microbiota/genética , RNA Ribossômico 16S/genética , Especificidade da EspécieRESUMO
This study investigated the prevalence of Actinomyces spp. in shallow, deep and very deep pockets of patients with chronic periodontitis compared to healthy controls and correlated the results with clinical status. Twenty patients with chronic periodontitis and 15 healthy subjects were enrolled in this study. Clinical indices were recorded in a six-point measurement per tooth. From each patient samples of supra and subgingival plaque were taken separately from teeth with shallow, deep and very deep pockets. Samples of supragingival plaque and sulcular microflora were collected from the healthy subjects. All the samples were cultivated on different media at 37ÌC in an anaerobic atmosphere for 7 days. All the suspect colonies were identified using a rapid ID 32 A system (bioMèrieux) and MALDI-TOF-MS analysis using an Autoflex II Instrument (Bruker Daltonics) together with in house developed identification software and a reference spectra database. A total of 977 strains were identified as Actinomyces. Actinomyces naeslundii/oris/johnsonii (430 isolates) was the most prevalent species and was found in all patients and in almost all of the healthy subjects. Significant differences (p=0.003) between the groups were found for Actinomyces odontolyticus/meyeri and Actinomyces israelii which were associated with periodontitis patients. Actinomyces dentalis was found in higher percentage (p=0.015) in the periodontitis group. Actinomyces gerencseriae and Actinomyces massiliensis were significantly more often found supragingivally than subgingivally (p=0.004, p=0.022, respectively) in the periodontitis group. Whether some Actinomyces species, definitely important plaque formers, are actively involved in the pathogenicity of chronic periodontitis needs further investigation.
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Actinomyces/isolamento & purificação , Actinomicose/epidemiologia , Actinomicose/microbiologia , Periodontite Crônica/microbiologia , Placa Dentária/microbiologia , Bolsa Gengival/microbiologia , Actinomyces/química , Actinomyces/classificação , Actinomyces/crescimento & desenvolvimento , Adulto , Idoso , Anaerobiose , Técnicas Bacteriológicas/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Denture prostheses are an ideal and extensive reservoir for microorganisms to attach to their surfaces. The aim of the study was to elucidate interactions between materials for the fabrication of denture bases and the attachment of microorganisms, focusing on respiratory pathogens and Candida species. Specimens (6 mm × 1 mm) with a standardized surface roughness (Sa = 0.1 µm) were prepared from heat-pressed polymethyl methacrylate (PMMA), CAD/CAM-processed PMMA, and CAD/CAM-processed polyether ether ketone (PEEK). The specimens were randomly placed in the vestibular areas of complete upper dentures in seven patients and were removed either after 24 h without any oral hygiene measures or after a period of four weeks. The microorganisms adherent to the surface of the specimens were cultivated and subsequently analyzed using mass spectrometry (MALDI-TOF). The means and standard deviations were calculated, and the data were analyzed using a two-way analysis of variance (ANOVA) and Tukey post-hoc test where appropriate (α = 0.05). There was a significant increase (p ≤ 0.004) in the total bacterial counts (CFU/mL) between the first (24 h) and the second (four weeks) measurements. Regarding quantitative microbiological analyses, no significant differences between the various materials were identified. Respiratory microorganisms were detected in all samples at both measurement time points, with a large variance between different patients. Only after four weeks, Candida species were identified on all materials but not in all participants. Candida species and respiratory microorganisms accumulate on various denture base resins. While no significant differences were identified between the materials, there was a tendency towards a more pronounced accumulation of microorganisms on conventionally processed PMMA.
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Anaerobes play an important role in clinically relevant infections and resistance is increasing worldwide. We tested 120 rare anaerobic isolates belonging to 16 genera for antimicrobial resistance using the agar dilution method and compared those results to the time-saving E-test method. The susceptibility data for 12 antimicrobial substances (benzylpenicillin, ampicillin/sulbactam, piperacillin/tazobactam, imipenem, meropenem, cefoxitin, metronidazole, moxifloxacin, clindamycin, doxycycline, tigecycline, eravacycline) were collected. Susceptibility testing showed low resistance to ß-lactam/ß-lactamase inhibitor combinations and no resistance to carbapenems and tigecycline. We observed moderate to high rates of resistance to moxifloxacin and clindamycin which differed depending on the methodology used. The essential and categorical agreement was over 90% for ampicillin/sulbactam, meropenem, moxifloxacin, and tigecycline. For metronidazole and clindamycin, the essential agreement was below 90% but the categorical agreement was near or above 90%. Penicillin presented with the lowest categorical agreement of 86.7% and a very high very major error rate of 13.3%. The resistance rates reported in this study are concerning and show the importance of routine susceptibility testing. Further investigations are necessary to determine the reason for high error rates and how to improve susceptibility testing of fastidious anaerobes.
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BACKGROUND: Rectal swabs are well-implemented screening tools for multidrug-resistant bacteria (MDRB). Since certified swabs such as the Copan eSwab system experienced a delivery bottleneck during the COVID-19 pandemic, commercially available alternatives such as commonly used double-tipped cotton swabs had to be investigated, especially considering their similarity to professional cotton swabs for microbiological purposes. METHODS: Diagnostic properties of commercial cotton swabs (comparable to Q-tips) and Copan eSwabs were qualitatively compared in a prospective single-center study using microbiological standard cultures and PCR methods for the detection of multidrug-resistant Gram-negative bacteria and vancomycin-resistant enterococci (VRE). RESULTS: A total of 196 swab pairs were collected from 164 participants. MDRB were detected in 36 of 164 cases (22%). There were neither false-negative nor false-positive results using commercial cotton swabs. In 8 of 196 samples (4.1%) MDRB species were detected only by using cotton swabs, including vancomycin-resistant Enterococcus faecium, OXA-48 producing Escherichia coli, ESBL-producing Klebsiella pneumoniae and ESBL-producing Escherichia coli. DISCUSSION: Commercial cotton swabs turned out to be a reliable alternative to Copan eSwabs. For practical use as a screening tool, relevant storage- and manufacturer-related contamination must be ruled out beforehand. CONCLUSIONS: Commonly available double-tipped cotton swabs can be used for rectal MDRB screening in the event of supply shortages of certified swabs. Further studies should clarify their suitability as a sampling system for nasopharyngeal MRSA carriage or even for the molecular biological detection of SARS-CoV-2.
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COVID-19 , Enterococos Resistentes à Vancomicina , COVID-19/diagnóstico , Escherichia coli , Humanos , Klebsiella pneumoniae , Pandemias , Estudos Prospectivos , SARS-CoV-2 , VancomicinaRESUMO
Actinomyces species play an important role in the pathogenesis of oral diseases and infections. Susceptibility testing is not always routinely performed, and one may oversee a shift in resistance patterns. The aim of the study was to analyze the antimicrobial susceptibility of 100 well-identified clinical oral isolates of Actinomyces spp. against eight selected antimicrobial agents using the agar dilution (AD) and E-Test (ET) methods. We observed no to low resistance against penicillin, ampicillin-sulbactam, meropenem, clindamycin, linezolid and tigecycline (0-2% ET, 0% AD) but high levels of resistance to moxifloxacin (93% ET, 87% AD) and daptomycin (83% ET, 95% AD). The essential agreement of the two methods was very good for benzylpenicillin (EA 95%) and meropenem (EA 92%). The ET method was reliable for correctly categorizing susceptibility, in comparison with the reference method agar dilution, except for daptomycin (categorical agreement 87%). Penicillin is still the first-choice antibiotic for therapy of diseases caused by Actinomyces spp.
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The phenotypic expression of antibiotic resistance genes (ARGs) can hamper the use of antibiotics as adjuncts to subgingival instrumentation in the treatment of periodontitis patients. The aim of the study was to analyze the relationship between the phenotypic and genotypic resistance against ampicillin-sulbactam, clindamycin, doxycycline and metronidazole of subgingival biofilm samples from 19 periodontitis patients. Samples were analyzed with shotgun sequencing and cultivated anaerobically for 7 days on microbiological culture media incorporating antibiotics. All growing isolates were identified to the species level using MALDI-TOF-MS and sequence analysis of the 16S ribosomal RNA (rRNA) gene. Phenotypic resistance was determined using EUCAST-breakpoints. The genetic profile of eight patients matched completely with phenotypical resistance to the tested antibiotics. The positive predictive values varied from 1.00 for clindamycin to 0.57 for doxycycline and 0.25 for ampicillin-sulbactam. No sample contained the nimI gene. It can be concluded that antibiotic resistance may be polygenetic and genes may be silent. Every biofilm sample harboring erm genes was phenotypic resistant. The absence of cfx and tet genes correlated to 100%, respectively, to 75%, with the absence of phenotypic resistance. The absence of nimI genes leads to the assumption that constitutive resistance among several species could explain the resistance to metronidazole.
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Wear-induced complications after cervical disc replacement (CDR) are rare. A literature review on this topic found only a few case reports. We present a case of late complications after implantation of two cervical disc replacements, which resulted in infectious/abrasion-induced mixed-type inflammation with extensive osteolysis. The diagnostic workup, surgical therapy and outcome are presented and discussed with a review of the recent literature.
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Osteólise , Substituição Total de Disco , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/cirurgia , Humanos , Osteólise/etiologia , Substituição Total de Disco/efeitos adversos , Substituição Total de Disco/métodosRESUMO
OBJECTIVES: This study aimed to evaluate the possible ability of dental impression tray adhesives to serve as a transmission medium for bacteria and fungi when reusable adhesive applicators are utilized. MATERIALS AND METHODS: Ten flasks with tray adhesive were monitored over a period of 12 weeks during clinical use for contamination with bacteria or fungi. Adhesive fluid samples were cultivated on eight different culture media. All grown colonies were identified by using mass spectrometry (MALDI-TOF). Isolates without reliable identification were either identified by Rapid ID 32 API-STREP V3.0 or by sequencing the 16S rRNA genes. RESULTS: After 4 weeks, bacterial growth was detected on chocolate blood agar plates in five different samples. The bacterial species were identified as Staphylococcus warnerii, Staphylococcus epidermidis, Staphylococcus pasteuri, Ralstonia insidiosa, and Alloiococcus otitidis. After 8 weeks Streptococcus oralis grew on a blood agar plate. In all samples, no fungi were identified. CONCLUSIONS: The disinfectant component of the tested tray adhesive seems to be effective. However, some bacteria survived in the flask for a clinically relevant time, which might result in a potential transmission to a new host.
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Cimentos Dentários , Técnica de Moldagem Odontológica , Ágar , Bactérias/genética , Meios de Cultura , Humanos , RNA Ribossômico 16S/genéticaRESUMO
Purpose: The aim of this study was to verify how the prevalence of viridans-streptococci is changed by two appointments of professional prophylaxis and after the subgingival instrumentation via scaling and root planing (SRP). Material and Methods: Samples of the subgingival biofilm were collected from 19 individuals with periodontitis receiving two appointments of professional prophylaxis and SRP before and after the treatment procedures and the presence of viridans-streptococci was analysed by microbiological cultivation. Non-parametric statistical testing using Friedman/Wilcoxon tests and chi-square testing was used for statistical analysis. Results: No statistically significant changes over time were found for the mutans-group. The prevalence of Streptococcus mitis decreased after two appointments of professional prophylaxis (pâ¯=â¯0.013). The prevalence of S. mitis decreased again after SRP (pâ¯<0.001). The prevalence of Streptococcus anginosus decreased after two appointments of professional prophylaxis (pâ¯=â¯0.002). After SRP five positive results for S. anginosus were detected (pâ¯=â¯0.026). For Streptococcus oralis and Streptococcus gordonii tendencies to statistical significance were found. The number of positive results for S. oralis increased after the first appointment of professional oral prophylaxis (pâ¯=â¯0.055). The number of positive results for S. gordonii increased after the first appointment of professional oral prophylaxis (pâ¯=â¯0.055). Conclusion: The step-wise periodontal therapy influences the prevalence of viridans-streptococci, especially S. mitis and S. anginosus. No tremendous increase of streptococci especially related to the carious process occurs in the subgingival biofilm. Clinical Relevance: The study reveals knowledge on changes of the composition of the subgingival biofilm due to different steps of periodontal therapy.
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Raspagem Dentária , Periodontite , Biofilmes , Humanos , Aplainamento Radicular , Streptococcus oralisRESUMO
OBJECTIVES: Bacteroides spp. are normal constituents of the human intestinal microflora, but they are also able to cause severe diseases. The aim of this study was to determine the diversity of antibiotic resistance genes found in phenotypically resistant Bacteroides and Parabacteroides strains. METHODS: A total of 71 phenotypically resistant Bacteroides spp. from human clinical specimens were screened for the antibiotic resistance genes cfiA, tetQ, tetM, tet36, cepA, cfxA, nim, ermG, ermF, bexA, blaVIM, blaNDM, blaKPC, blaOXA-48 and blaGES. The presence of these genes was compared with phenotypic resistance to ampicillin/sulbactam, cefoxitin, ceftolozane/tazobactam, piperacillin/tazobactam, imipenem, meropenem, meropenem/vaborbactam, clindamycin, moxifloxacin, tigecycline, eravacycline and metronidazole. RESULTS: tetQ was the most frequently detected gene, followed by cfiA, ermF, cfxA, ermG, cepA, nim and bexA. None of the strains were positive for tetM, tet36, blaVIM, blaNDM, blaKPC, blaOXA-48 or blaGES. Resistance to the tested ß-lactams was mainly linked to the presence of the cfiA gene. Clindamycin resistance correlated with the presence of the genes ermG and ermF. The bexA gene was found in six strains, but only two of them were resistant to moxifloxacin. Tigecycline and eravacycline showed good activities despite the frequent occurrence of tetQ. The nim gene was detected in six isolates, five of which were resistant to metronidazole. CONCLUSION: The findings of our study support the general belief that antimicrobial resistance within Bacteroides should be taken into consideration. This underlines the necessity of reliable routine antimicrobial susceptibility test methods for anaerobic bacteria and the implementation of antimicrobial surveillance programmes worldwide.
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Antibacterianos , Anti-Infecciosos , Antibacterianos/farmacologia , Bacteroides/genética , Farmacorresistência Bacteriana , Genes Bacterianos , Alemanha , Humanos , Testes de Sensibilidade MicrobianaRESUMO
Background: Due to the increasing emergence of multi-resistant bacteria the search for alternative antimicrobial substances is of high interest. Promising agents are antimicrobial peptides which are host defense molecules of the innate immune system in a wide range of different species. Objectives: The aim of this study was to assess the activity of nisin, melittin, lactoferrin, parasin-1 and LL-37 against 35 oral bacteria and Candida albicans employing the gold standard method for anaerobic susceptibility testing. Methods: The activity of the peptides was determined by an agar dilution method under anaerobic and aerobic conditions. The test media contained final peptide concentrations between 0.125 µg/ml and 8 µg/ml (melittin, lactoferrin, parasin-1, LL-37) and between 0.125 µg/ml and 128 µg/ml (nisin). Results: Nisin completely inhibited the growth of Megasphaera sp., Bifidobacterium longum, Parvimonas micra, Actinomyces israelii, Actinomyces naeslundii, Actinomyces odontolyticus, Prevotella intermedia, Streptococcus anginosus, Streptococcus constellatus and Staphylococcus aureus. Melittin and lactoferrin reduced the growth of Megasphaera sp., P. micra, B. longum (melittin) and Selenomonas flueggei (lactoferrin). Parasin-1 and LL-37 showed no activity. Conclusion: AMPs, especially nisin and to a smaller degree lactoferrin, might be promising alternatives to antibiotics because of their antimicrobial activity, high resistance to environmental conditions and partially low costs.
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Infections with Neisseriameningitidis are life-threatening conditions, generally presenting as meningitis. This case of a young woman who had a history of paroxysmal nocturnal hemoglobinuria under treatment with the complement inhibitor eculizumab had been presented with septic shock. While blood cultures were positive for Neisseria meningitidis, she showed no evidence for bacterial meningitis in the cerebrospinal fluid. This case shows that meningococcal sepsis without signs for bacterial meningitis despite repetitive vaccinations is possible in adults under eculizumab.
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Hemoglobinúria Paroxística , Meningite Meningocócica/diagnóstico , Infecções Meningocócicas/diagnóstico , Infecções Meningocócicas/tratamento farmacológico , Choque Séptico , Adulto , Anticorpos Monoclonais Humanizados/efeitos adversos , Feminino , HumanosRESUMO
The aim of this study was to estimate differences in the prevalence of oral streptococcal species in the subgingival biofilm of patients with aggressive periodontitis and of healthy controls. Thirty-three patients with clinical and radiological proof of aggressive periodontitis and 20 healthy subjects were enrolled in this study. Clinical indices were recorded in a six-point measurement per tooth. Samples of the subgingival biofilm were taken with paper points from four teeth of each individual. Alpha- and non-haemolytic, small and catalase-negative colonies were biochemically identified using a rapid ID 32 STREP system and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. A total of 118 strains of oral streptococci (11 species) were identified and Streptococcus sanguinis was found significantly more often in healthy subjects (P=0.001). Conversely, the absence of S. sanguinis was associated with high values of clinical indices (P=0.001-0.002). Aggressive periodontitis seems to be associated with a loss of colonization of S. sanguinis. Whether or not S. sanguinis offers protection against aggressive periodontitis needs to be determined. Otherwise, there were no significant differences in the distribution of oral streptococcal species in patients and healthy subjects.
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Biofilmes/crescimento & desenvolvimento , Gengiva/microbiologia , Periodontite/microbiologia , Streptococcus sanguis/crescimento & desenvolvimento , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Boca , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Streptococcus/classificação , Streptococcus/crescimento & desenvolvimento , Streptococcus/isolamento & purificação , Streptococcus sanguis/isolamento & purificaçãoRESUMO
Currently, there is minimal clinical data regarding biofilm composition on the surface of denture bases and the clinical tissue compatibility. Therefore, the aim of this experimental study was to compare the bacterial colonization and the tissue compatibility of a hypoallergenic polyamide with a frequently used PMMA resin tested intraorally in a randomized split-mouth design. Test specimens made of polyamide (n = 10) and PMMA (n = 10) were attached over a molar band appliance in oral cavity of 10 subjects. A cytological smear test was done from palatal mucosa at baseline and after four weeks. The monolayers were inspected for micronuclei. After four weeks in situ, the appliance was removed. The test specimens were immediately cultivated on non-selective and selective nutrient media. All growing colonies were identified using VITEK-MS. The anonymized results were analyzed descriptively. A total of 110 different bacterial species could be isolated, including putative pathogens. An average of 17.8 different bacterial species grew on the PMMA specimens, and 17.3 on the polyamide specimens. The highest number of different bacterial species was n = 24, found on a PMMA specimen. On the two specimens, a similar bacterial distribution was observed. Micronuclei, as a marker for genotoxic potential of dental materials, were not detected. This study indicates that the composition of bacterial biofilm developed on these resins after four weeks is not influenced by the type of resin itself. The two materials showed no cytological differences. This investigation suggests that polyamide and PMMA are suitable for clinical use as denture base material.
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In this study, the effect of bacterial multispecies communities on the adhesion of Streptococcus mutans and Streptococcus sanguinis to dental restorative material was investigated. The saliva-coated specimens of zirconia and composite were incubated with the following combinations: single species, S. mutans or S. sanguinis; two species, single species combined with other oral streptococci; multiple species, combination of Actinomyces naeslundii, Fusobacterium nucleatum, and Prevotella ssp.; and the two-species combinations. The adherent bacteria were counted after plating of serial dilutions. Effects of material and bacteria on adhesion of S. mutans and S. sanguinis were evaluated with multiple linear regression analyses. No significant differences between the materials regarding the adhesion of S. mutans and S. sanguinis were observed. The adhesion of S. mutans was negatively influenced by the presence of other streptococci. Enhancing effects (610.6%) were seen in the presence of Prevotella intermedia. The adhesion of S. sanguinis decreased in the presence of other bacteria, except F. nucleatum (increase of 717.4%). Significant inhibitory effects were detected in the presence of S. mutans and A. naeslundii (reduction of 95.9% and 78.5%, respectively). The results of this study suggest that adhesion of both types of streptococci to restorative materials is influenced by various bacterial interactions.
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Two matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS)-based methods were compared for their ability to identify viridans streptococci. One approach employed a reference database and software developed in-house. All inhouse measurements were performed using an Autoflex II Instrument (Bruker Daltonics GmbH, Germany). The other system, a VITEK-MS (BioMérieux, France) was operated on the commercially available V2.0 Knowledge Base for Clinical Use database. Clinical isolates of viridans streptococci (n=184) were examined. Discrepant results were resolved by 16S rDNA sequencing. Species-level identification percentages were compared by a chi-square test. The in-house method correctly identified 179 (97%) and 175 (95%) isolates to the group and species level respectively. In comparison, the VITEK-MS system correctly identified 145 (79%) isolates to the group and species level. The difference between the two methods was statistically significant at both group and species levels. Using the Autoflex II instrument combined with an extraction method instead of whole cell analysis resulted in more reliable viridans streptococci identification. Our results suggest that combining extraction with powerful analysis software and the careful choice of well-identified strains included into the database was useful for identifying viridans streptococci species.