Are patents important indicators of innovation for Chagas disease treatment?

INTRODUCTION: Chagas disease is a neglected, endemic disease in 21 countries, spreading to non-endemic countries too. Like other neglected diseases affecting primarily low- and middle-income countries, low investment and the absence of new chemical entities from the industry occurred. Increased knowledge about the parasite, drug targets, and vector control has been observed, but this was not translated into new drugs. The partnerships of pharmaceutical companies with academies and consolidated networks to increment the new drugs and treatment research in Chagas disease are shown. The current review analyzes in detail the patents dealing with compounds candidates for new drugs and treatment. The patent search was performed using Orbit Intelligence® software in the 2001-2021 period. AREAS COVERED: The author focused specifically on patents for the treatment, the new candidates disclosed in the patents, and the barriers to innovation. EXPERT OPINION: Patents in Chagas disease have been increasing in the last years, although they do not bring new compounds to an effective treatment.

Multi-domain probiotic consortium as an alternative to chemical remediation of oil spills at coral reefs and adjacent sites.

BACKGROUND: Beginning in the last century, coral reefs have suffered the consequences of anthropogenic activities, including oil contamination. Chemical remediation methods, such as dispersants, can cause substantial harm to corals and reduce their resilience to stressors. To evaluate the impacts of oil contamination and find potential alternative solutions to chemical dispersants, we conducted a mesocosm experiment with the fire coral Millepora alcicornis, which is sensitive to environmental changes. We exposed M. alcicornis to a realistic oil-spill scenario in which we applied an innovative multi-domain bioremediator consortium (bacteria, filamentous fungi, and yeast) and a chemical dispersant (Corexit® 9500, one of the most widely used dispersants), to assess the effects on host health and host-associated microbial communities. RESULTS: The selected multi-domain microbial consortium helped to mitigate the impacts of the oil, substantially degrading the polycyclic aromatic and n-alkane fractions and maintaining the physiological integrity of the corals. Exposure to Corexit 9500 negatively impacted the host physiology and altered the coral-associated microbial community. After exposure, the abundances of certain bacterial genera such as Rugeria and Roseovarius increased, as previously reported in stressed or diseased corals. We also identified several bioindicators of Corexit 9500 in the microbiome. The impact of Corexit 9500 on the coral health and microbial community was far greater than oil alone, killing corals after only 4 days of exposure in the flow-through system. In the treatments with Corexit 9500, the action of the bioremediator consortium could not be observed directly because of the extreme toxicity of the dispersant to M. alcicornis and its associated microbiome. CONCLUSIONS: Our results emphasize the importance of investigating the host-associated microbiome in order to detect and mitigate the effects of oil contamination on corals and the potential role of microbial mitigation and bioindicators as conservation tools. Chemical dispersants were far more damaging to corals and their associated microbiome than oil, and should not be used close to coral reefs. This study can aid in decision-making to minimize the negative effects of oil and dispersants on coral reefs. Video abstract.

Microbial bioremediation of oil contaminated seawater: A survey of patent deposits and the characterization of the top genera applied.

Petroleum has been the world's major source of energy since the middle of the twentieth century, leading to positive changes but also social, political, and environmental problems worldwide. Oil contamination affects all ecosystems, and the remediation of polluted sites using environmentally friendly strategies is crucial. Here, we report an analysis of the patent documents of potential petroleum bioremediation techniques that use microbes to clean seawater. The patent search was performed using Orbit Intelligence®, SciFinder® and the Derwent World Patents Index®. A group of 500 patent documents were validated according to the search objective and carefully studied. Increases in patent deposits coincide with periods following widely reported oil spills, suggesting a relationship between media disclosure and stimulation of innovation activities. China leads the list of countries with patent applications in bioremediation with 152 deposits, followed by Russia with 133 and the US with 48. These three countries have completely different temporal deposit profiles, influenced by their historical, political, and economic scenarios. A total of 368 patents described degradation of the oil compounds exclusively by bacteria, 24 by fungi and yeasts, 1 by Archaea, 1 using a microalgal strain, and 32 by mixed consortia. The leading microbial genera found in the patents are Pseudomonas (114 patents), Bacillus (75), and Rhodococcus (60). In the top-10 list of microbial strains mostly cited/claimed, no genera are obligate hydrocarbonoclastic bacteria. This fact, together with the broad pattern found in the main International Patent Classification (IPC) codes, suggest that most of the documents are general bioremediation approaches and not focused on oil-polluted seawater. This work highlights the importance of stimulating the development of innovative environmentally friendly strategies focused on the degradation of oil hydrocarbons in marine ecosystems.

Does Low-Protein Diet Influence the Uremic Toxin Serum Levels From the Gut Microbiota in Nondialysis Chronic Kidney Disease Patients?

OBJECTIVES: To evaluate the effects of low-protein diet (LPD) on uremic toxins and the gut microbiota profile in nondialysis chronic kidney disease (CKD) patients. DESIGN AND METHODS: Longitudinal study with 30 nondialysis CKD patients (stage 3-4) undergoing LPD for 6 months. Adherence to the diet was evaluated based on the calculation of protein equivalent of nitrogen appearance from the 24-hour urine analysis. Good adherence to LPD was considered when protein intake was from 90% to 110% of the prescribed amount (0.6 g/kg/day). Food intake was analyzed by the 24-hour recall method. The anthropometric, biochemical and lipid profile parameters were measured according to standard methods. Uremic toxin serum levels (indoxyl sulfate, p-cresyl sulfate, indole-3-acetic acid) were obtained by reversed-phase high-performance liquid chromatography (RP-HPLC). Fecal samples were collected to evaluate the gut microbiota profile through polymerase chain reaction and denaturing gradient gel electrophoresis. Statistical analysis was performed by the SPSS 23.0 program software. RESULTS: Patients who adhered to the diet (n = 14) (0.7 ± 0.2 g/kg/day) presented an improvement in renal function (nonsignificant) and reduction in total and low-density lipoprotein cholesterol (183.9 ± 48.5-155.7 ± 37.2 mg/dL, P = .01; 99.4 ± 41.3-76.4 ± 33.2 mg/dL, P = .01, respectively). After 6 months of nutricional intervention, p-cresyl sulfate serum levels were reduced significantly in patients who adhered to the LPD (19.3 [9.6-24.7] to 15.5 [9.8-24.1] mg/L, P = .03), and in contrast, the levels were increased in patients who did not adhere (13.9 [8.0-24.8] to 24.3 [8.1-39.2] mg/L, P = .004). In addition, using the denaturing gradient gel electrophoresis technique, it was observed change in the intestinal microbiota profile after LPD intervention in both groups, and the number of bands was positively associated with protein intake (r = 0.44, P = .04). CONCLUSION: LPD seems be a good strategy to reduce the uremic toxins production by the gut microbiota in nondialysis CKD patients.

Probiotic Supplementation in Chronic Kidney Disease: A Double-blind, Randomized, Placebo-controlled Trial.

OBJECTIVE: The objective of the study was to evaluate the effects of probiotic supplementation on the gut microbiota profile and inflammatory markers in chronic kidney disease patients undergoing maintenance hemodialysis (HD). DESIGN AND METHODS: This was a randomized, double-blind, placebo-controlled study. Forty-six HD patients were assigned to receive 1 of 2 treatments: probiotic (n = 23; Streptococcus thermophilus, Lactobacillus acidophilus e Bifidobacterialongum, 90 billion colony-forming units per day) or placebo (n = 23) daily for 3 months. Blood and feces were collected at baseline and after intervention. The inflammatory markers (C-reactive protein and interleukin-6) were analyzed by immunoenzymatic assay (enzyme-linked immunosorbent assay). Uremic toxins plasma levels (indoxyl sulfate, p-cresyl sulfate, and indole-3-acetic acid) were obtained by Reversed-Phase High-Performance Liquid Chromatography. Routine laboratory parameters were measured by standard techniques. Fecal pH was measured by the colorimetric method, and the gut microbiota profile was assessed by Denaturing Gradient Gel Electrophoresis analysis. RESULTS: Sixteen patients remained in the probiotic group (11 men, 53.6 ± 11.0 year old, 25.3 ± 4.6 kg/m2) and 17 in the placebo group (10 men, 50.3 ± 8.5 year old, 25.2 ± 5.7 kg/m2). After probiotic supplementation there was a significant increase in serum urea (from 149.6 ± 34.2 mg/dL to 172.6 ± 45.0 mg/dL, P = .02), potassium (from 4.4 ± 0.4 mmol/L to 4.8 ± 0.4 mmol/L, P = .02), and indoxyl sulfate (from 31.2 ± 15.9 to 36.5 ± 15.0 mg/dL, P = .02). The fecal pH was reduced from 7.2 ± 0.8 to 6.5 ± 0.5 (P = .01). These parameters did not change significantly in placebo group. Changes in the percentage delta (Δ) between groups were exhibited with no statistical differences observed. The inflammatory markers and gut profile were not altered by supplementation. CONCLUSIONS: Aprobiotic supplementation failed to reduce uremic toxins and inflammatory markers. Therefore, probiotic therapy should be chosen with caution in HD patients. Further studies addressing probiotic therapy in chronic kidney disease patients are needed.

Ecology and biotechnological potential of bacterial community from three marine sponges of the coast of Rio de Janeiro, Brazil.

Marine sponges has been a large reservoir of microbial diversity, with the presence of many species specific populations as well as producing biologically active compounds, which has attracted great biotechnological interest. In order to verify the influence of the environment in the composition of the bacterial community present in marine sponges and biotechnological potential of bacteria isolated from these organisms, three species of sponges and the waters surrounding them were collected in different beaches of Rio de Janeiro, Brazil. The profile of the bacterial community present in sponges and water was obtained by PCR-DGGE technique and the biotechnological potential of the strains isolated by producing amylase, cellulase, protease and biosurfactants. The results showed that despite the influence of the environment in the composition of the microbial community, studied marine sponges shown to have specific bacterial populations, with some, showing potential in the production of substances of biotechnological applications.

Ecology and biotechnological potential of bacterial community from three marine sponges of the coast of Rio de Janeiro, Brazil

ABSTRACT Marine sponges has been a large reservoir of microbial diversity, with the presence of many species specific populations as well as producing biologically active compounds, which has attracted great biotechnological interest. In order to verify the influence of the environment in the composition of the bacterial community present in marine sponges and biotechnological potential of bacteria isolated from these organisms, three species of sponges and the waters surrounding them were collected in different beaches of Rio de Janeiro, Brazil. The profile of the bacterial community present in sponges and water was obtained by PCR-DGGE technique and the biotechnological potential of the strains isolated by producing amylase, cellulase, protease and biosurfactants. The results showed that despite the influence of the environment in the composition of the microbial community, studied marine sponges shown to have specific bacterial populations, with some, showing potential in the production of substances of biotechnological applications.

Cyanobacterial and microeukaryotic profiles of healthy, diseased, and dead Millepora alcicornis from the South Atlantic.

Coral reefs are at risk due to events associated with human activities, which have resulted in the increasing occurrence of coral diseases. Corals live in symbiotic relationships with different microorganisms, such as cyanobacteria, a very important group. Members of the phylum Cyanobacteria are found in great abundance in the marine environment and may play an essential role in keeping corals healthy but may also be pathogenic. Furthermore, some studies are showing a rise in cyanobacterial abundance in coral reefs as a result of climate change. The current study aimed to improve our understanding of the relationship between cyanobacteria and coral health. Our results revealed that the cyanobacterial genus GPI (Anabaena) is a possible opportunistic pathogen of the coral species Millepora alcicornis in the South Atlantic Ocean. Furthermore, the bacterial and microeukaryotic profile of healthy, diseased, and post-disease (skeletal) regions of affected coral indicated that a microbial consortium composed of Anabaena sp., Prosthecochloris sp., and microeukaryotes could be involved in this pathogenicity or could be taking advantage of the diseased state.

Is there interaction between gut microbial profile and cardiovascular risk in chronic kidney disease patients?

AIM: To evaluate the gut microbial profile in chronic kidney disease (CKD) patients and evaluate the possible relationship with inflammation and cardiovascular risk. PATIENTS & METHODS: Markers inflammation plasma and bacterial community profile (denaturing gradient gel electrophoresis) were analyzed. RESULTS: The average number of bands was not different in healthy individuals and CKD patients. The number of bands was negatively associated with plasma levels of VCAM-1 in patients. Flavobacteriaceae bacterium and Listeria monocytogenes were found in patients and Lachnospiraceae bacterium and Butyrivibrio crossotus in healthy individuals. CONCLUSION: Although CKD patients did not present altered gut microbial profile, the sequencing of bands suggested a different microbiota between groups. The result suggests a possible relationship between gut microbiota and cardiovascular risk in CKD patients.

Herpesvirus in the oral cavity of children with leukaemia and its impact on the oral bacterial community profile.

AIMS: This cross-sectional study investigated the association between eight herpesviruses and the bacterial community profiles from the oral cavity of children with and without leukaemia. METHODS: Sixty participants (aged 3-13), divided into the leukaemia group (LG) and healthy group (HG), were evaluated. Collection of medical data, intraoral examination and collection of clinical specimens were carried out. Single PCR and nested-PCR techniques were used to identify the viral types; denaturing gradient gel electrophoresis (DGGE) and real-time PCR techniques were used to evaluate the profile and abundance of bacterial communities. RESULTS: All the children with leukaemia were positive for at least one type of herpesvirus, compared with healthy participants (33.3%; p<0.000). Human cytomegalovirus (HCMV; 46.7%), human herpesvirus-7 (HHV-7; 20%) and HHV-8 (77.3%) were in higher prevalence in the LG (p ≤ 0.01). Children with leukaemia had positive associations with the presence of HCMV, HHV-7 and HHV-8 in the oral cavity when under chemotherapy (p<0.05). There was a qualitative (means of DGGE bands) and quantitative (means of 16S rRNA gene abundance) difference in relation to the bacterial community between the two groups (p<0.05). CONCLUSIONS: Based on the results, the prevalence of herpesviruses and the qualitative bacterial profiles was higher in children with leukaemia and HCMV, HHV-7 and HHV-8 were related to the use of chemotherapy. Moreover, HHV-6 was correlated with an increased bacterial community profile in patients with leukaemia (p<0.05). More attention should be paid to the oral health of these individuals, mainly those under chemotherapy, in order to prevent infections by opportunistic pathogens.

Climate change affects key nitrogen-fixing bacterial populations on coral reefs.

Coral reefs are at serious risk due to events associated with global climate change. Elevated ocean temperatures have unpredictable consequences for the ocean's biogeochemical cycles. The nitrogen cycle is driven by complex microbial transformations, including nitrogen fixation. This study investigated the effects of increased seawater temperature on bacteria able to fix nitrogen (diazotrophs) that live in association with the mussid coral Mussismilia harttii. Consistent increases in diazotroph abundances and diversities were found at increased temperatures. Moreover, gradual shifts in the dominance of particular diazotroph populations occurred as temperature increased, indicating a potential future scenario of climate change. The temperature-sensitive diazotrophs may provide useful bioindicators of the effects of thermal stress on coral reef health, allowing the impact of thermal anomalies to be monitored. In addition, our findings support the development of research on different strategies to improve the fitness of corals during events of thermal stress, such as augmentation with specific diazotrophs.

Molecular microbiological evaluation of passive ultrasonic activation as a supplementary disinfecting step: a clinical study.

INTRODUCTION: This in vivo study used molecular microbiology methods to evaluate the effects of passive ultrasonic irrigation (PUI) as a supplementary disinfecting step after root canal preparation. METHODS: Samples were taken from 10 necrotic root canals of teeth with apical periodontitis before (S1) and after rotary nickel-titanium instrumentation using 2.5% NaOCl as the irrigant (S2) and then after PUI for NaOCl activation (S3). The parameters examined included the incidence of positive broad-range polymerase chain reaction (PCR) results for bacterial presence, the impact on bacterial diversity evaluated by PCR-denaturing gradient gel electrophoresis (DGGE), the quantitative bacterial reduction determined by real-time PCR, and the identification of persistent species by clone library analysis. RESULTS: All S1 samples were positive for bacteria in all tests. Treatment procedures were significantly effective in reducing the incidence of positive results for bacteria, the number of bacterial cells (infectious bioburden), and the bacterial diversity (number of species and abundance). However, the supplementary PUI approach did not succeed in significantly enhancing disinfection beyond that achieved by chemomechanical preparation. Several bacterial species/phylotypes were identified in post-treatment samples that were positive for bacteria. CONCLUSIONS: Findings from this clinical study including a small sample size suggest that PUI can be ineffective in significantly improving disinfection of the main root canal after chemomechanical procedures.

Physiological aspects of mangrove (Laguncularia racemosa) grown in microcosms with oil-degrading bacteria and oil contaminated sediment.

To assess the severity of oil spills on mangroves, diagnosis of the vegetation health is crucial. Some aspects of photosynthesis such as photochemical efficiency and leaf pigment composition together with the level of oxidative stress may constitute reliable indicators for vegetation health. To test this approach 14 month old Laguncularia racemosa were contaminated with 5 L m(-2) of the marine fuel oil MF-380 and treated with an oil degrading bacterial consortium in microcosms. Contamination resulted in a 20% decrease in shoot dry weight after 128 days. Photochemical efficiency, pigment content, catalase and ascorbate peroxidase remained unchanged. Multivariate ordination of DGGE microbial community fingerprints revealed a pronounced separation between the oil contaminated and the non-contaminated samples. Further studies are necessary before physiological parameters can be recommended as indicators for plant's health in oil polluted mangroves.

Supplementing the antimicrobial effects of chemomechanical debridement with either passive ultrasonic irrigation or a final rinse with chlorhexidine: a clinical study.

INTRODUCTION: The ability of 2 different approaches to supplement the antimicrobial effects of chemomechanical debridement in infected root canals was compared in vivo. METHODS: Samples from necrotic root canals of teeth with apical periodontitis were taken at the baseline (S1), after preparation with rotary nickel-titanium BioRaCe instruments and 2.5% NaOCl irrigation (S2), and then after either passive ultrasonic irrigation (PUI) for activation of NaOCl (n = 13) or a final rinse with 2% chlorhexidine (CHX) (n = 14) (S3). The incidence of positive culture for bacteria and fungi as well as positive broad-range polymerase chain reaction (PCR) results for bacteria, fungi, and archaea was determined. RESULTS: All S1 samples were positive for bacteria in all methods. Fungi were not detected, and archaea occurred in only one S1 sample. Treatment procedures were significantly effective in reducing the incidence of positive culture and PCR results. Although both supplementary approaches reduced the incidence of positive bacteriologic results when compared with postinstrumentation samples, reduction was not statistically significant (P > .05). There was no significant difference for intergroup comparisons either (P > .05). CONCLUSIONS: Although supplementary disinfection with either PUI or a final rinse with CHX can reduce the number of cases with positive culture and PCR results for bacteria, many cases still remain with detectable bacteria in the main root canal. Research on alternative or supplementary antimicrobial methods or substances should be encouraged.

Viral-bacterial associations in acute apical abscesses.

OBJECTIVE: Viral-bacterial and bacterial synergism have been suggested to contribute to the pathogenesis of several human diseases. This study sought to investigate the possible associations between 9 candidate endodontic bacterial pathogens and 9 human viruses in samples from acute apical abscesses. STUDY DESIGN: DNA extracts from purulent exudate aspirates of 33 cases of acute apical abscess were surveyed for the presence of 9 selected bacterial species using a 16S ribosomal RNA gene-based nested polymerase chain reaction (PCR) approach. Single or nested PCR assays were used for detection of the human papillomavirus (HPV) and herpesviruses types 1 to 8. RESULTS: Two-thirds of the abscess samples were positive for at least one of the target viruses. Specifically, the most frequently detected viruses were HHV-8 (54.5%); HPV (9%); and varicella zoster virus (VZV), Epstein-Barr virus (EBV), and HHV-6 (6%). Bacterial DNA was present in all cases and the most prevalent bacterial species were Treponema denticola (70%), Tannerella forsythia (67%), Porphyromonas endodontalis (67%), Dialister invisus (61%), and Dialister pneumosintes (57.5%). HHV-8 was positively associated with 7 of the target bacterial species and HPV with 4, but all these associations were weak. Several bacterial pairs showed a moderate positive association. Viral coinfection was found in 6 abscess cases, but no significant viral association could be determined. CONCLUSIONS: Findings demonstrated that bacterial and viral DNA occurred concomitantly in two-thirds of the samples from endodontic abscesses. Although this may suggest a role for viruses in the etiology of apical abscesses, the possibility also exists that the presence of viruses in abscess samples is merely a consequence of the bacterially induced disease process. Further studies are necessary to clarify the role of these viral-bacterial interactions, if any, in the pathogenesis of acute apical abscesses.

Identification of herpesviruses types 1 to 8 and human papillomavirus in acute apical abscesses.

INTRODUCTION: It has been suggested that viruses, especially herpesviruses, can play a role in the pathogenesis of marginal and apical periodontitis. This study aimed to detect herpesviruses types 1 to 8, namely herpes simplex virus (HSV-1/2), varicella zoster virus (VZV), Epstein-Barr virus (EBV), human cytomegalovirus (HCMV), human herpesvirus-6 (HHV-6), human herpesvirus-7 (HHV-7), and human herpesvirus-8 (HHV-8) as well as human papillomavirus (HPV) in acute apical abscesses. METHODS: Twenty-four samples were taken by aspiration of the purulent exudate from acute apical abscesses. DNA extracted from clinical samples served as a template in single or nested polymerase chain reaction (PCR) assays for the detection of the target viruses. RESULTS: Control PCR reactions with ß-globin gene primers revealed that all samples but one had detectable human DNA. Of the 23 abscess samples positive for the ß-globin gene, 14 (61%) were positive for at least one of the target human viruses. Thirteen (56.5%) cases had herpesvirus: HHV-8 occurred in 11 (48%), VZV and HHV-6B in two (9%), and HHV-7 and HSV-1/2 in one (4%). EBV and HCMV were not present in any of the examined samples. HPV was detected in three (13%) abscess samples. Viral coinfection was found in five cases, with one case harboring three of the targeted viruses. CONCLUSION: A large number of abscess samples were positive for at least one target virus. Unexpectedly, HHV-8 was for the first time detected and in a high prevalence. Papillomavirus and other herpesviruses were also found for the first time in endodontic abscesses. Although these findings suggest an association, the specific role of viruses in the pathogenesis of acute apical abscesses awaits further clarification.

18S rDNA sequences from microeukaryotes reveal oil indicators in mangrove sediment.

BACKGROUND: Microeukaryotes are an effective indicator of the presence of environmental contaminants. However, the characterisation of these organisms by conventional tools is often inefficient, and recent molecular studies have revealed a great diversity of microeukaryotes. The full extent of this diversity is unknown, and therefore, the distribution, ecological role and responses to anthropogenic effects of microeukaryotes are rather obscure. The majority of oil from oceanic oil spills (e.g., the May 2010 accident in the Gulf of Mexico) converges on coastal ecosystems such as mangroves, which are threatened with worldwide disappearance, highlighting the need for efficient tools to indicate the presence of oil in these environments. However, no studies have used molecular methods to assess the effects of oil contamination in mangrove sediment on microeukaryotes as a group. METHODOLOGY/PRINCIPAL FINDINGS: We evaluated the population dynamics and the prevailing 18S rDNA phylotypes of microeukaryotes in mangrove sediment microcosms with and without oil contamination, using PCR/DGGE and clone libraries. We found that microeukaryotes are useful for monitoring oil contamination in mangroves. Our clone library analysis revealed a decrease in both diversity and species richness after contamination. The phylogenetic group that showed the greatest sensitivity to oil was the Nematoda. After contamination, a large increase in the abundance of the groups Bacillariophyta (diatoms) and Biosoecida was detected. The oil-contaminated samples were almost entirely dominated by organisms related to Bacillariophyta sp. and Cafeteria minima, which indicates that these groups are possible targets for biomonitoring oil in mangroves. The DGGE fingerprints also indicated shifts in microeukaryote profiles; specific band sequencing indicated the appearance of Bacillariophyta sp. only in contaminated samples and Nematoda only in non-contaminated sediment. CONCLUSIONS/SIGNIFICANCE: We believe that the microeukaryotic targets indicated by our work will be of great applicability in biomonitoring hydrocarbons in mangroves under oil contamination risk or during recovery strategies.

Comparison of endodontic bacterial community structures in root-canal-treated teeth with or without apical periodontitis.

Bacterial occurrence in treated root canals, even in patients without post-treatment apical periodontitis, raises the possibility that factors other than mere bacterial presence can be determinants for a favourable outcome of endodontic treatment. Because these factors may be related to the bacterial communities colonizing the root canal, including virulence, density and interactions, the objective of this study was to compare the community structures found in root-canal-treated teeth with (12 samples) and without (11 samples) apical periodontitis lesions by means of a PCR-denaturing gradient gel electrophoresis fingerprinting approach. Results confirmed a polymicrobial composition even in treated patients without post-treatment disease. A large microbial community diversity was observed for treated teeth both with or without disease, but no specific pattern was detected for diseased teeth. Nevertheless, the number of bands from samples with apical periodontitis lesions was statistically significantly higher (P=0.04) than that from samples collected from root-canal-treated teeth without post-treatment apical periodontitis. Furthermore, predominant bands in samples from patients with apical disease were also observed.

Bacterial community profiling of cryogenically ground samples from the apical and coronal root segments of teeth with apical periodontitis.

Bacteria located at the apical part of infected root canals are arguably directly involved in the pathogenesis of apical periodontitis. This study was conducted to profile and further compare the bacterial communities established at the apical and middle/coronal segments of infected root canals. Extracted teeth with attached apical periodontitis lesions were sectioned so as to obtain two root fragments representing the apical third and the coronal two thirds. Root fragments were subjected to a cryogenic grinding approach. DNA was extracted from root powder samples and used as a template for bacterial community profiling using a 16S ribosomal RNA gene-based seminested polymerase chain reaction/denaturing gradient gel electrophoresis approach. The mean number of bands in apical samples from teeth with primary infections was 28, ranging from 18 to 48, whereas in the middle/coronal samples, it was also 28, ranging from 19 to 36. Findings showed that the profile of bacterial community colonizing the apical third of infected root canals is as diverse as that occurring at the middle/coronal thirds. A high variability was observed for both interindividual (samples from the same region but from different patients) and intraindividual (samples from different regions of the same tooth) comparisons. The methodology used to prepare and analyze samples was highly effective in disclosing a previously unanticipated broad diversity of endodontic bacterial communities, especially at the apical part of infected root canals.