Bacterial translocation and mortality on rat model of intestinal ischemia and obstruction

Abstract Purpose: To develop an experimental model of intestinal ischemia and obstruction followed by surgical resection of the damaged segment and reestablishment of intestinal transit, looking at bacterial translocation and survival. Methods: After anesthesia, Wistar rats was subject to laparotomy, intestinal ischemia and obstruction through an ileal ligature 1.5cm of ileum cecal valve; and the mesenteric vessels that irrigate upstream of the obstruction site to approximately 7 to 10 cm were ligated. Abdominal wall was closed. Three, six or twenty-four hours after, rats were subject to enterectomy followed by an end to end anastomosis. After 24h, mesenteric lymph nodes, liver, spleen and lung tissues were surgically removed. It was studied survival rate and bacterial translocation. GraphPadPrism statistical program was used. Results: Animals with intestinal ischemia and obstruction for 3 hours survived 24 hours after enterectomy; 6hx24h: survival was 70% at 24 hours; 24hx24h: survival was 70% and 40%, before and after enterectomy, respectively. Culture of tissues showed positivity on the 6hx24h and negativity on the 3hx24h. Conclusion: The model that best approached the clinic was the one of 6x24h of ischemia and intestinal obstruction, in which it was observed bacterial translocation and low mortality rate.

Bacterial diversity of symptomatic primary endodontic infection by clonal analysis.

The aim of this study was to explore the bacterial diversity of 10 root canals with acute apical abscess using clonal analysis. Samples were collected from 10 patients and submitted to bacterial DNA isolation, 16S rRNA gene amplification, cloning, and sequencing. A bacterial genomic library was constructed and bacterial diversity was estimated. The mean number of taxa per canal was 15, ranging from 11 to 21. A total of 689 clones were analyzed and 76 phylotypes identified, of which 47 (61.84%) were different species and 29 (38.15%) were taxa reported as yet-uncultivable or as yet-uncharacterized species. Prevotella spp., Fusobacterium nucleatum, Filifactor alocis, and Peptostreptococcus stomatis were the most frequently detected species, followed by Dialister invisus, Phocaeicola abscessus, the uncharacterized Lachnospiraceae oral clone, Porphyromonas spp., and Parvimonas micra. Eight phyla were detected and the most frequently identified taxa belonged to the phylum Firmicutes (43.5%), followed by Bacteroidetes (22.5%) and Proteobacteria (13.2%). No species was detected in all studied samples and some species were identified in only one case. It was concluded that acute primary endodontic infection is characterized by wide bacterial diversity and a high intersubject variability was observed. Anaerobic Gram-negative bacteria belonging to the phylum Firmicutes, followed by Bacteroidetes, were the most frequently detected microorganisms.

Bacterial diversity of symptomatic primary endodontic infection by clonal analysis

Abstract The aim of this study was to explore the bacterial diversity of 10 root canals with acute apical abscess using clonal analysis. Samples were collected from 10 patients and submitted to bacterial DNA isolation, 16S rRNA gene amplification, cloning, and sequencing. A bacterial genomic library was constructed and bacterial diversity was estimated. The mean number of taxa per canal was 15, ranging from 11 to 21. A total of 689 clones were analyzed and 76 phylotypes identified, of which 47 (61.84%) were different species and 29 (38.15%) were taxa reported as yet-uncultivable or as yet-uncharacterized species. Prevotella spp., Fusobacterium nucleatum, Filifactor alocis, and Peptostreptococcus stomatis were the most frequently detected species, followed by Dialister invisus, Phocaeicola abscessus, the uncharacterized Lachnospiraceae oral clone, Porphyromonas spp., and Parvimonas micra. Eight phyla were detected and the most frequently identified taxa belonged to the phylum Firmicutes (43.5%), followed by Bacteroidetes (22.5%) and Proteobacteria (13.2%). No species was detected in all studied samples and some species were identified in only one case. It was concluded that acute primary endodontic infection is characterized by wide bacterial diversity and a high intersubject variability was observed. Anaerobic Gram-negative bacteria belonging to the phylum Firmicutes, followed by Bacteroidetes, were the most frequently detected microorganisms.

Utilidad de la espectrometría de masas MALDI-TOF en la identificación de bacterias anaerobias / Utility of MALDI-TOF MS for the identification of anaerobic bacteria

El análisis de espectrometría de masas mediante la metodología hoy conocida como MALDI-TOF MS (Matrix-assited laser desorption/ionization time-of-flight mass spectrometry) se ha convertido en un recurso de referencia para la identificación de microorganismos en microbiología clínica. No obstante, los datos relativos a algunos grupos de microorganismos son todavía controvertidos. El objetivo del presente estudio fue determinar la utilidad del MALDI-TOF MS para la identificación de aislamientos clínicos de bacterias anaerobias. Se analizaron 106 aislamientos de bacterias anaerobias mediante MALDI-TOF MS y por pruebas bioquímicas convencionales. En aquellos casos en los que la identificación por metodología convencional no era aplicable o frente a una discordancia de resultados entre las metodologías citadas, se realizó la secuenciación del gen 16S del ARNr. El método convencional y el MALDI-TOF MS coincidieron a nivel de género y especie en un 95,3 % de los casos considerando la totalidad de los aislamientos estudiados. Al considerar solo el conjunto de los bacilos gram negativos, la coincidencia fue del 91,4 %; entre los bacilos gram positivos, fue del 100 %; los 8 aislados de cocos gram positivos estudiados coincidieron y también hubo coincidencia en el único coco gram negativo incluido. Los datos obtenidos en este estudio demuestran que el MALDI-TOF MS ofrece la posibilidad de llegar a una adecuada identificación de bacterias anaerobias

The analysis by MALDI-TOF MS (Matrix-assited laser desorption/ionization time-of-flight mass spectrometry) has become a reference method for the identification of microorganisms in Clinical Microbiology. However, data on some groups of microorganisms are still controversial. The aim of this study is to determine the utility of MALDI-TOF MS for the identification of clinical isolates of anaerobic bacteria. One-hundred and six anaerobic bacteria isolates were analyzed by MALDI-TOF MS and by conventional biochemical tests. In those cases where identification by conventional methodology was not applicable or in the face of discordance between sequencing methodologies, 16 S rRNA gene sequence analysis was performed. The conventional method and MALDI-TOF MS agreed at genus and species level by 95.3 %. Concordance in gram-negative bacilli was 91.4% and 100% among gram-positive bacilli; there was also concordance both in the 8 isolates studied in gram-positive cocci and in the single gram-negative cocci included. The data obtained in this study demonstrate that MALDI-TOF MS offers the possibility of adequate identification of anaerobic bacteria

Susceptibility of as-yet-uncultivated and difficult-to-culture bacteria to chemomechanical procedures.

INTRODUCTION: A significant portion of the bacteria taking part of the microbiome associated with apical periodontitis still remain to be cultivated and phenotypically characterized. This molecular study evaluated the prevalence of selected as-yet-uncultivated and difficult-to-culture bacterial taxa in infected root canals and their susceptibility to chemomechanical procedures. METHODS: Root canals of single-rooted teeth with apical periodontitis were prepared using rotary nickel-titanium instruments and 2.5% sodium hypochlorite as the irrigant. DNA extracts from samples taken before (S1) and after (S2) chemomechanical preparation were surveyed for the presence of 7 as-yet-uncultivated phylotypes and 1 difficult-to-culture species using end-point polymerase chain reaction. Samples were also subjected to quantitative analysis of total bacteria and levels of the 2 most prevalent taxa. RESULTS: Bacteroidaceae sp. HOT-272 (24%) and Fretibacterium fastidiosum (20%) were the most prevalent taxa in S1. Their mean counts in S1 were 8.25 × 10(3) and 2.13 × 10(3) rRNA gene copies, corresponding to 0.18% and 0.55% of the total bacteria. Chemomechanical debridement promoted a highly statistically significant reduction in total bacterial counts (P < .001), but 64% of the canals were still positive for bacterial presence. Of the target taxa, only Bacteroidaceae sp. HOT-272 and F. fastidiosum were detected in S2 (each one in 1 sample). The reduction in counts of both taxa was also highly significant (P < .001). CONCLUSIONS: Findings confirmed that several as-yet-uncultivated and difficult-to-grow bacterial taxa can participate in the microbiome associated with apical periodontitis. Two of them were found in relatively high prevalence but rarely as a dominant species. Chemomechanical procedures were highly effective in completely eliminating these taxa or at least substantially reducing their numbers.

Subgingival biodiversity in subjects with uncontrolled type-2 diabetes and chronic periodontitis.

BACKGROUND AND OBJECTIVE: There is a bidirectional relationship between periodontal disease and type-2 diabetes mellitus (DM). Inflammatory mediators may negatively affect glycemic control, and increased glucose levels and resultant glycation end-products may alter the host response against bacterial infection. However, no agreement has been reached regarding the effect of DM on periodontal subgingival microbiota. Therefore, the purpose of the present study was to compare the subgingival biodiversity in deep periodontal pockets of subjects with chronic periodontitis and either uncontrolled type-2 diabetes or no diabetes using 16S rRNA gene cloning and sequencing. MATERIAL AND METHODS: Twelve subjects with uncontrolled type-2 diabetes (glycated hemoglobin > 8%) and eleven nondiabetic subjects presenting severe and generalized chronic periodontitis were selected. Subgingival biofilm from periodontal pockets > 5 mm were assessed using the 16S rRNA gene cloning and sequencing technique. RESULTS: Significant differences were observed in subgingival microbiota between diabetic and nondiabetic subjects. Diabetic subjects presented higher percentages of total clones of TM7, Aggregatibacter, Neisseria, Gemella, Eikenella, Selenomonas, Actinomyces, Capnocytophaga, Fusobacterium, Veillonella and Streptococcus genera, and lower percentages of Porphyromonas, Filifactor, Eubacterium, Synergistetes, Tannerella and Treponema genera than nondiabetic individuals (p < 0.05). Moreover, some phylotypes, such as Fusobacterium nucleatum, Veillonella parvula, V. dispar and Eikenella corrodens were detected significantly more often in diabetic subjects than in nondiabetic subjects (p < 0.05). CONCLUSION: Subjects with uncontrolled type-2 diabetes and chronic periodontitis presented significant dissimilarities in subgingival biodiversity compared with nondiabetic subjects.

Peptidolytic microbial community of methanogenic reactors from two modified UASBs of brewery industries

We studied the peptide-degrading anaerobic communities of methanogenic reactors from two mesophilic full-scale modified upflow anaerobic sludge blanket (UASB) reactors treating brewery wastewater in Colombia. Most probable number (MPN) counts varied between 7.1 x 10(8) and 6.6 x 10(9) bacteria/g volatile suspended solids VSS (Methanogenic Reactor 1) and 7.2 x 10(6) and 6.4 x 10(7) bacteria/g (VSS) (Methanogenic Reactor 2). Metabolites detected in the highest positive MPN dilutions in both reactors were mostly acetate, propionate, isovalerate and, in some cases, negligible concentrations of butyrate. Using the highest positive dilutions of MPN counts, 50 dominant strains were isolated from both reactors, and 12 strains were selected for sequencing their 16S rRNA gene based on their phenotypic characteristics. The small-subunit rRNA gene sequences indicated that these strains were affiliated to the families Propionibacteriaceae, Clostridiaceae and Syntrophomonadaceae in the low G + C gram-positive group and Desulfovibrio spp. in the class d-Proteobacteria. The main metabolites detected in the highest positive dilutions of MPN and the presence of Syntrophomonadaceae indicate the effect of the syntrophic associations on the bioconversion of these substrates in methanogenic reactors. Additionally, the potential utilization of external electron acceptors for the complete degradation of amino acids by Clostridium strains confirms the relevance of these acceptors in the transformation of peptides and amino acids in these systems.

An interleukin-1beta (IL-1beta) single-nucleotide polymorphism at position 3954 and red complex periodontopathogens independently and additively modulate the levels of IL-1beta in diseased periodontal tissues.

Inflammatory cytokines such as interleukin-1beta (IL-1beta) are involved in the pathogenesis of periodontal diseases. A high individual variation in the levels of IL-1beta mRNA has been verified, which is possibly determined by genetic polymorphisms and/or by the presence of periodontopathogens such as Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Aggregatibacter actinomycetemcomitans. In this study, we investigated the role of an IL-1beta promoter single-nucleotide polymorphism at position 3954 [IL-1beta(3954) SNP] and the presence of the periodontopathogens in the determination of the IL-1beta levels in the periodontal tissues of nonsmoking chronic periodontitis (CP) patients (n = 117) and control (C) subjects (n = 175) and the possible correlations with the clinical parameters of the disease. IL-1beta(3954) SNP was investigated by restriction fragment length polymorphism, while the IL-1beta levels and the presence of the periodontopathogens were determined by real-time PCR. Similar frequencies of IL-1beta(3954) SNP were found in the C and CP groups, in spite of a trend toward a higher incidence of T alleles in the CP group. The IL-1beta(3954) SNP CT and TT genotypes, as well as P. gingivalis, T. forsythia, and T. denticola, were associated with higher IL-1beta levels and with higher values of the clinical parameters of disease severity. Concomitant analyses demonstrate that IL-1beta(3954) and the red complex periodontopathogens were found to independently and additively modulate the levels of IL-1beta in periodontal tissues. Similarly, the concurrent presence of both factors was associated with increased scores of disease severity. IL-1beta(3954) genotypes and red complex periodontopathogens, individually and additively, modulate the levels of IL-1beta in the diseased tissues of nonsmoking CP patients and, consequently, are potentially involved in the determination of the disease outcome.

Biodiversity and phylogenetic analysis of culturable bacteria indigenous to Khewra salt mine of Pakistan and their industrial importance

Culturable bacterial biodiversity and industrial importance of the isolates indigenous to Khewra salt mine, Pakistan was assessed. PCR Amplification of 16S rDNA of isolates was carried out by using universal primers FD1 and rP1and products were sequenced commercially. These gene sequences were compared with other gene sequences in the GenBank databases to find the closely related sequences. The alignment of these sequences with sequences available from GenBank database was carried out to construct a phylogenetic tree for these bacteria. These genes were deposited to GenBank and accession numbers were obtained. Most of the isolates belonged to different species of genus Bacillus, sharing 92-99 percent 16S rDNA identity with the respective type strain. Other isolates had close similarities with Escherichia coli, Staphylococcus arlettae and Staphylococcus gallinarum with 97 percent, 98 percent and 99 percent 16S rDNA similarity respectively. The abilities of isolates to produce industrial enzymes (amylase, carboxymethylcellulase, xylanase, cellulase and protease) were checked. All isolates were tested against starch, carboxymethylcellulose (CMC), xylane, cellulose, and casein degradation in plate assays. BPT-5, 11,18,19 and 25 indicated the production of copious amounts of carbohydrates and protein degrading enzymes. Based on this study it can be concluded that Khewra salt mine is populated with diverse bacterial groups, which are potential source of industrial enzymes for commercial applications.

Avaliou-se a biodiversidade e a importância industrial de bactérias indígenas da mina de sal Khewra, Paquistão. Efetuou-se a amplificação do 16S rDNA dos isolados por PCR empregando-se os iniciadores universais FD1 e rP1, e os produtos foram seqüenciados comercialmente. Essas seqüências de genes foram comparadas com outras seqüências disponíveis no GenBank a fim de encontrar seqüências relacionadas, construindo-se uma árvore filogenética para essas bactérias. Os genes foram depositados no GenBank obtendo-se os números de acesso. A maioria dos isolados pertenceu a diferentes espécies do gênero Bacillus, apresentando 92-99 por cento de identidade de 16S rDNA com a respectiva cepa de referencia. Outros isolados apresentaram alta similaridade com Escherichia coli, Staphylococcus arlettae e Staphylococcus gallinarum, com 97 por cento, 98 por cento e 99 por cento de similaridade de16S rDNA, respectivamente. A capacidade dos isolados produzirem enzimas industriais (amilase, carboximetilcelulase, xilanase, celulase e protease) foi verificada. Todos os isolados foram testados em placas quanto a degradação de amido, carboximetilcelulose, xilana, celulose e caseína. Os isolados BPT-5, 11, 18, 19 e 25 produziram grandes quantidades de enzimas degradadoras de carboidratos e proteínas. Conclui-se que a mina de Sal Khewra apresenta diferentes grupos de bactérias, que são fontes potenciais de enzimas industriais de aplicação comercial.

Comparison of antagonistic ability against enteropathogens by G+ and G- anaerobic dominant components of human fecal microbiota.

To confirm if anaerobic G+-components are those responsible for the function of colonization resistance, obligate anaerobic G+- and G- -bacteria from normal dominant microbiota of human feces were isolated from three successive collections and then used in in vitro assays for antagonism against two enteropathogenic bacteria. The production of inhibitory diffusible compounds was determined on supplemented BHI agar and MRS agar media for G- - and G+-bacteria, respectively. Salmonella enterica subsp. enterica serovar Typhimurium and Shigella sonnei were used as indicators. G+-bacteria presented a higher overall antagonistic frequency against both pathogenic bacteria (57 and 64 % for S. enterica serovar Typhimurium and S. sonnei, respectively) when compared to G+-microorganisms but with a quite elevated variation between volunteers (0-100 %) and collection samples (40-72 and 40-80 % for S. enterica sv. Typhimurium and S. sonnei, respectively). On the other hand, only three among 143 G- -isolates tested showed antagonistic activity. The results showed that, at least in vitro, obligate anaerobic G+-components of the dominant human fecal microbiota present a higher potential for antagonism against the enteropathogenic models tested than do G- -bacteria.

["In vitro" activity of ten antimicrobial agents against anaerobic bacteria. A collaborative study, 1999-2002]. / Actividad "in vitro" de 10 antimicrobianos frente a bacterias anaerobias. Estudio multicéntrico, 1999-2002.

The antimicrobial activity of ampicillin, ampicillin-sulbactam, cefoxitin, ceftriaxone, imipenem, piperacillin, piperacillin-tazobactam, clindamycin, metronidazole, and azitromycin was assesed against 166 strains of anaerobic bacteria recovered from eight hospitals in Buenos Aires. The strains studied were Bacteroides fragilis group (65), Fusobacterium spp. (26), Prevotella spp. (21), Porphyromonas spp. (10), Clostridium difficile (10), other clostridia (12), and gram-positive cocci (22). The MICs were determined by the agar dilution method according to NCCLS document M11-A5. Metronidazole and piperacillin-tazobactam were the most active antimicrobial agents tested and exhibited MIC90 values of < or = 2 microg/ml and < or = 4 microg/ml against gram-negative organisms, and < or = 2 microg/ml, and < or = 8 microg/ml against gram-positive organisms, respectively. Among beta-lactams the activity against gram-negative rods was in the following order: imipenem > piperacillin > cefoxitin > ceftriaxone > ampicillin. Among the gram-positive bacteria the decreased activity was: piperacillin > imipenem > cefoxitin > ceftriaxone > ampicillin. The majority of the species studied showed different degrees of resistance to clindamycin and azitromycin. Nevertheless, 90% of Fusobacterium nucleatum and Porphyromonas spp. isolates were inhibited by 0.125 mg/ml of clindamycin and azitromycin, respectively.

Actividad “in vitro” de 10 antimicrobianos frente a bacterias anaerobias: Estudio multicéntrico, 1999-2002 / “In vitro” activity of ten antimicrobial agents against anaerobic bacteria. A collaborative study, 1999-2002

Se evaluó la actividad de ampicilina, ampicilina-sulbactama, cefoxitina, ceftriaxona, imipenem, piperacilina, piperacilina-tazobactama, clindamicina, metronidazol y azitromicina frente a 166 cepas de bacterias anaerobias aisladas en 8 hospitales de Buenos Aires. Se estudiaron: Bacteroides grupo fragilis (65), Fusobacterium spp. (26), Prevotella spp. (21), Porphyromonas spp. (10), Clostridium difficile (10), otros clostridios (12) y cocos gram-positivos (22). Las CIMs se determinaron usando el método patrón de dilución en agar recomendado por el NCCLS, documento M11-A5. Los antibióticos más activos fueron metronidazol y piperacilina-tazobactama que exhibieron valores de CIM90£ 2 µg/ml y £ 4 µg/ml frente a los microorganismos gram-negativos y £ 2 µg/ml y £ 8 µg/ml frente a los microorganismos gram-positivos, respectivamente. Entre los b-lactámicos el orden de actividad frente a bacilos gram-negativos fue: imipenem > piperacilina > cefoxitina > ceftriaxona > ampicilina. En gram-positivos la actividad decreciente fue: piperacilina> imipenem > cefoxitina > ceftriaxona > ampicilina. La mayoría de las especies estudiadas mostraron distintos niveles de resistencia con clindamicina y azitromicina. Sin embargo, el 90% de las cepas de Fusobacterium nucleatum y Por-phyromonas spp. fue inhibido por una concentración de 0,125 µg/ml de clindamicina y azitromicina, respectivamente.

The antimicrobial activity of ampicillin, ampicillin-sulbactam, cefoxitin, ceftriaxone, imipenem, piperacillin, piperacillin-tazobactam, clindamycin, metronidazole, and azitromycin was assesed against 166 strains of anaerobic bacteria recovered from eight hospitals in Buenos Aires. The strains studied were Bacteroidesfragilis group (65), Fusobacterium spp. (26), Prevotella spp. (21), Porphyromonas spp. (10), Clostridium difficile (10), other clostridia (12), and gram-positive cocci (22). The MICs were determined by the agar dilution method according to NCCLS document M11-A5. Metronidazole and piperacillin-tazobactam were the most active antimicrobial agents tested and exhibited MIC90values of £ 2 µg/ml and £ 4 µg/ml against gram-negative organisms, and £ 2 µg/ml, and £ 8 µg/ml against gram-positive organisms, respectively. Among b-lactams the activity against gram-negative rods was in the following order: imipenem> piperacillin > cefoxitin > ceftriaxone > ampicillin. Among the gram-positive bacteria the decreased activity was: piperacillin> imipenem> cefoxitin > ceftriaxone > ampicillin. The majority of the species studied showed different degrees of resistance to clindamycin and azitromycin. Nevertheless, 90% of Fusobacterium nucleatum and Porphyromonas spp. isolates were inhibited by 0.125 mg/ml of clindamycin and azitromycin, respectively.

Nested PCR detection of Centipeda periodontii in primary endodontic infections.

In recent years, molecular genetic methodologies have provided significant additional knowledge about components of the microbiota associated with infections of endodontic origin. Following this research line, the purpose of the present study was to investigate the prevalence of Centipeda periodontii in primary endodontic infections using a species-specific nested PCR assay. Samples were collected from fifty teeth having carious lesions, necrotic pulps, and different forms of periradicular diseases. DNA extracted from the samples was initially amplified using universal 16S rDNA primers, and a second round of amplification used the first PCR products to detect a specific fragment of C. periodontii 16S rDNA. This species was detected in 3 (13%) of 23 asymptomatic cases, in 1 (14%) of 7 cases diagnosed as acute apical periodontitis, and in 3 (15%) of 20 pus samples aspirated from acute periradicular abscesses. There was no significant association between C. periodontii and the presence of clinical symptoms. Overall, C. periodontii was detected in 14% of the cases of endodontic infections. This is probably the hitherto first study to detect C. periodontii in primary endodontic infections. The specific role played by this bacterial species in infections of endodontic origin awaits further clarification.

Phylogenetic characterization of a corrosive consortium isolated from a sour gas pipeline.

Biocorrosion is a common problem in oil and gas industry facilities. Characterization of the microbial populations responsible for biocorrosion and the interactions between different microorganisms with metallic surfaces is required in order to implement efficient monitoring and control strategies. Denaturing gradient gel electrophoresis (DGGE) analysis was used to separate PCR products and sequence analysis revealed the bacterial composition of a consortium obtained from a sour gas pipeline in the Gulf of Mexico. Only one species of sulfate-reducing bacteria (SRB) was detected in this consortium. The rest of the population consisted of enteric bacteria with different characteristics and metabolic capabilities potentially related to biocorrosion. Therefore, several types of bacteria may be involved in biocorrosion arising from natural biofilms that develop in industrial facilities. The low abundance of the detected SRB was evidenced by environmental scanning electron microscopy (ESEM). In addition, the localized corrosion of pipeline steel in the presence of the consortium was clearly observed by ESEM after removing the adhered bacteria.

Avaliaçäo clínica e microbiológica da saúde periodontal de crianças portadoras de fissura completa de lábio e palato unilateral comparada a de crianças sem fissuras na mesma faixa etária (5-6 anos) / Clinical and microbiological evaluation of periodontal condition in 5-6 years old children with unilateral complete cleft lip and palate compared to normal controls

Crianças portadoras de fissura de lábio e palato apresentam alteraçöes anatômicas decorrentes da própria anomalia e dos procedimentos terapêuticos para a sua reabilitaçäo, que podem predispô-las a um maior acúmulo de placa bacteriana, principalmente na regiäo anterior da maxila. Com o objetivo de comparar as condiçöes clínicas, através da utilizaçäo dos índices de placa (IP) e gengival (IG) de Loe (1967) e a presença das bactérias P. gingivalis, P. nigrescens e T. denticola, através da técnica "Slot Immunoblot", foram avaliadas 57 crianças com dentiçäo decídua e idades entre 5 e 6 anos, sendo 30 portadoras de fissura completa de lábio e palato unilateral (grupo experimental) e 27 crianças sem fissura (grupo controle). O IP médio do grupo experimental (1,82 ñ 0,38) foi superior ao do grupo controle (1,63 ñ 0,38), embora sem diferença estatisticamente significante, enquanto o IG médio do grupo experimental (1,05 ñ 0,22) foi significantemente superior ao do grupo controle (0,79 ñ 0,33) (p<0,05). No grupo experimental a área da fissura (2 sítios), com IP médio de 2,04 ñ 0,58 e IG médio de 1,11 ñ 0,26, quando comparada à regiäo posterior (4 sítios), com IP médio de 1,74 ñ 0,37 e IG médio de 1,04 ñ 0,26, mostrou difrença estatisticamente significante somente em relaçäo ao IP. Considerando a severidade, a maioria das crianças dos dois grupos apresentou IP de grau moderado, 73,33 por cento para o grupo experimental e 81,48 por cento para o grupo controle; enquanto, para o IG, a maioria apresentou severidade de grau baixo, sendo de 53,33 por cento para o grupo experimental e de 70,37 por cento para a grupo controle...

Coprothermobacter platensis sp. nov., a new anaerobic proteolytic thermophilic bacterium isolated from an anaerobic mesophilic sludge.

A new anaerobic, proteolytic, moderately thermophilic bacterium, strain 3RT, was isolated from a methanogenic mesophilic reactor treating protein-rich wastewater. The cells were Gram-negative, non-spore-forming, non-motile rods. The DNA base composition was 43 mol% G + C. The optimum pH and temperature for growth were 7.0 and 55 degrees C respectively. The bacterium fermented gelatin, casein, bovine albumin, peptone and yeast extract. Glucose, fructose, sucrose, maltose and starch were poorly fermented. The major fermentation products from glucose were acetate, CO2 and H2 and, from gelatin, propionate was also detected. Growth on glucose was stimulated by thiosulfate, which was reduced to sulfide. Sulfate and nitrate were not reduced. 16S rRNA gene analysis revealed that the isolated bacterial strain was phylogenetically related to Coprothermobacter proteolyticus (96.3% sequence similarity), the only known species within the genus. DNA-DNA hybridization analysis demonstrated a very low level of homology, indicating that the isolated strain and C. proteolyticus were not related at species level. Therefore, it is proposed to classify the described strain in the genus Coprothermobacter as a new species, Coprothermobacter platensis. The type strain of C. platensis is strain 3RT (= DSM 11748T).

Microbiología de la enfermedad periodontal / Microbiology of periodontal disease

Existen una gran variedad de microorganismos relacionados con la enfermedad periodontal. Por lo general, los que se aíslan en la placa supragingival, son los mismos que se encuentran en la placa subgingival. Lo que hasta el momento se encuentra comprobado, es que las diferencias entre la placa asociada a sitios sanos en comparación con sitios periodontalmente afectados y aquella en posición supragingival comparada con la que se encuentra entre la encía y el diente, solamente difieren en la proporción relativa de algunos microorganismos en los conteos microbianos, parece que la mayor proporción de espiroquetas y bacteroides presentes en la placa subgingival, es el factor determinante para que la enfermedad esté activa