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1.
Viruses ; 14(2)2022 01 18.
Article in English | MEDLINE | ID: mdl-35215772

ABSTRACT

Identification of the SARS-CoV-2 virus by RT-PCR from a nasopharyngeal swab sample is a common test for diagnosing COVID-19. However, some patients present clinical, laboratorial, and radiological evidence of COVID-19 infection with negative RT-PCR result(s). Thus, we assessed whether positive results were associated with intubation and mortality. This study was conducted in a Brazilian tertiary hospital from March to August of 2020. All patients had clinical, laboratory, and radiological diagnosis of COVID-19. They were divided into two groups: positive (+) RT-PCR group, with 2292 participants, and negative (-) RT-PCR group, with 706 participants. Patients with negative RT-PCR testing and an alternative most probable diagnosis were excluded from the study. The RT-PCR(+) group presented increased risk of intensive care unit (ICU) admission, mechanical ventilation, length of hospital stay, and 28-day mortality, when compared to the RT-PCR(-) group. A positive SARS-CoV-2 RT-PCR result was independently associated with intubation and 28 day in-hospital mortality. Accordingly, we concluded that patients with a COVID-19 diagnosis based on clinical data, despite a negative RT-PCR test from nasopharyngeal samples, presented more favorable outcomes than patients with positive RT-PCR test(s).


Subject(s)
COVID-19 Nucleic Acid Testing/statistics & numerical data , COVID-19/diagnosis , Reverse Transcriptase Polymerase Chain Reaction/statistics & numerical data , SARS-CoV-2/genetics , Academic Medical Centers/statistics & numerical data , Aged , Brazil , COVID-19/mortality , COVID-19/virology , COVID-19 Nucleic Acid Testing/methods , Female , Hospital Mortality , Hospitalization/statistics & numerical data , Humans , Intensive Care Units/statistics & numerical data , Male , Middle Aged , Nasopharynx/virology , Retrospective Studies , Risk Factors
2.
Healthcare (Basel) ; 10(2)2022 Jan 21.
Article in English | MEDLINE | ID: mdl-35206821

ABSTRACT

BACKGROUND: The decision to intubate COVID-19 patients receiving non-invasive respiratory support is challenging, requiring a fine balance between early intubation and risks of invasive mechanical ventilation versus the adverse effects of delaying intubation. This present study analyzes the association between intubation day and mortality in COVID-19 patients. METHODS: We performed a unicentric retrospective cohort study considering all COVID-19 patients consecutively admitted between March 2020 and August 2020 requiring invasive mechanical ventilation. The primary outcome was all-cause mortality within 28 days after intubation, and a Cox model was used to evaluate the effect of time from onset of symptoms to intubation in mortality. RESULTS: A total of 592 (20%) patients of 3020 admitted with COVID-19 were intubated during study period, and 310 patients who were intubated deceased 28 days after intubation. Each additional day between the onset of symptoms and intubation was significantly associated with higher in-hospital death (adjusted hazard ratio, 1.018; 95% CI, 1.005-1.03). CONCLUSION: Among patients infected with SARS-CoV-2 who were intubated and mechanically ventilated, delaying intubation in the course of symptoms may be associated with higher mortality. TRIAL REGISTRATION: The study protocol was approved by the local Ethics Committee (opinion number 3.990.817; CAAE: 30417520.0.0000.0068).

3.
BMJ Open ; 11(6): e051706, 2021 06 30.
Article in English | MEDLINE | ID: mdl-34193506

ABSTRACT

INTRODUCTION: COVID-19 may lead to persistent and potentially incapacitating clinical manifestations (post-acute sequelae of SARS-CoV-2 infection (PASC)). Using easy-to-apply questionnaires and scales (often by telephone interviewing), several studies evaluated samples of COVID-19 inpatients from 4 weeks to several months after discharge. However, studies conducting systematic multidisciplinary assessments of PASC manifestations are scarce, with thorough in-person objective evaluations restricted to modestly sized subsamples presenting greatest disease severity. METHODS AND ANALYSES: We will conduct a prospective observational study of surviving individuals (above 18 years of age) from a cohort of over 3000 subjects with laboratory-confirmed COVID-19 who were treated as inpatients at the largest academic health centre in Sao Paulo, Brazil (Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo). All eligible subjects will be consecutively invited to undergo a 1-2-day series of multidisciplinary assessments at 2 time-points, respectively, at 6-9 months and 12-15 months after discharge. Assessment schedules will include detailed multidomain questionnaires applied by medical research staff, self-report scales, objective evaluations of cardiopulmonary functioning, physical functionality and olfactory status, standardised neurological, psychiatric and cognitive examinations, as well as diagnostic laboratory, muscle ultrasound and chest imaging exams. Remaining material from blood tests will be incorporated by a local biobank for use in future investigations on inflammatory markers, genomics, transcriptomics, peptidomics and metabolomics. ETHICS AND DISSEMINATION: All components of this programme have been approved by local research ethics committees. We aim to provide insights into the frequency and severity of chronic/post-COVID multiorgan symptoms, as well as their interrelationships and associations with acute disease features, sociodemographic variables and environmental exposures. Findings will be disseminated in peer-reviewed journals and at scientific meetings. Additionally, we aim to provide a data repository to allow future pathophysiological investigations relating clinical PASC features to biomarker data extracted from blood samples. TRIAL REGISTRATION NUMBER: RBR-8z7v5wc; Pre-results.


Subject(s)
COVID-19 , SARS-CoV-2 , Brazil , COVID-19/complications , Hospitalization , Humans , Observational Studies as Topic , Post-Acute COVID-19 Syndrome
4.
Pacing Clin Electrophysiol ; 43(5): 495-502, 2020 05.
Article in English | MEDLINE | ID: mdl-32277706

ABSTRACT

BACKGROUND: Venous obstructions are frequent in patients with transvenous leads, although related clinical findings are rarely reported. After lead replacement or upgrade procedures, these lesions are even more frequent, but there is still no evidence to support this observation. AIM: To investigate the incidence and possible risk factors for upper extremity deep venous thrombosis (UEDVT) and pulmonary embolism (PE) after lead replacement or upgrade procedures. METHODS: Prospective cohort carried out between April 2013 and July 2016. Preoperative evaluation included venous ultrasound and pulmonary angiotomography. Diagnostic exams were repeated postoperatively to detect the study outcomes. Multivariate logistic regression models were used to identify prognostic factors. RESULTS: Among the 84 patients included, 44 (52.4%) were female and mean age was 59.3 ± 15.2 years. Lead malfunctioning (75.0%) was the main surgical procedure indication. Lead removal was performed in 44 (52.4%) cases. The rate of postoperative combined events was 32.6%, with 24 (28.6%) cases of UEDVT and six (7.1%) cases of PE. Clinical manifestations of deep venous thrombosis occurred in 10 (11.9%) patients. Independent prognostic factors for UEDVT were severe collateral circulation in the preoperative venography (odds ratio [OR] 4.7; 95% confidence interval [CI] 1.1-19.8; P = .037) and transvenous lead extraction (OR 27.4; 95% CI 5.8-128.8; P < .0001). CONCLUSION: Reoperations involving previously implanted transvenous leads present high rates of thromboembolic complications. Transvenous lead extraction had a significant impact on the development of UEDVT. These results show the need of further studies to evaluate the role of preventive strategies for this subgroup of patients.


Subject(s)
Device Removal/adverse effects , Electrodes, Implanted/adverse effects , Pulmonary Embolism/etiology , Upper Extremity Deep Vein Thrombosis/etiology , Female , Humans , Male , Middle Aged , Prospective Studies , Pulmonary Embolism/diagnostic imaging , Reoperation , Risk Factors , Upper Extremity Deep Vein Thrombosis/diagnostic imaging
5.
Eur J Cardiovasc Nurs ; 17(3): 196-206, 2018 03.
Article in English | MEDLINE | ID: mdl-29067836

ABSTRACT

BACKGROUND: Implantable cardioverter-defibrillator (ICD) therapy significantly improves the survival of patients who are at high risk for sudden cardiac death. However, it is unclear whether this survival is accompanied by impairment on quality of life (QoL). OBJECTIVES: This systematic review sought to describe whether ICD therapy, as compared with standard treatment, can have an impact on QoL outcomes. METHODS: Extensive literature searches were carried out in PubMed, EMBASE, LILACS and Cochrane Library. Eligible studies were randomized controlled trials (RCTs) of ICD versus medical therapy that reported valid and reliable measures of QoL. Included studies were reviewed to determine baseline patient characteristics, mean duration of follow-up, questionnaires used to assess QoL and association between QoL scores and ICD shock therapy. RESULTS: Seven studies, enrolling a total of 5,701 patients, were included in this review. The analyzed trials showed conflicting results about the impact of ICD on QoL outcomes. Among the secondary prevention studies, CIDS reported a clear benefit from ICD and AVID showed no difference between ICD and amiodarone groups. Of the primary prevention trials, AMIOVIRT, MADIT II, DEFINITE, and SCD-HeFT found no evidence of impaired QoL in patients with an ICD. Evidence for an association between ICD shocks and QoL was mixed and seemed to depend on the interval between shocks and QoL assessment. CONCLUSION: There was no evidence of impaired QoL in patients with an ICD. However, ICD patients must be educated of all possible risks and benefits, including transitory declines in QoL after ICD shocks.


Subject(s)
Death, Sudden, Cardiac/prevention & control , Defibrillators, Implantable , Quality of Life , Amiodarone/therapeutic use , Anti-Arrhythmia Agents/therapeutic use , Humans , Randomized Controlled Trials as Topic , Surveys and Questionnaires
6.
Echocardiography ; 32(9): 1400-6, 2015 Sep.
Article in English | MEDLINE | ID: mdl-25640015

ABSTRACT

BACKGROUND: Left ventricular (LV) dysfunction is the major reason for poor outcomes in patients with congenital complete atrioventricular block (CCAVB) and pacemaker. Long-term pacing has been associated with LV mechanical dyssynchrony. However, the relationship of dyssynchrony and LV dysfunction is not clear. OBJECTIVE: We sought to evaluate the prevalence of LV dyssynchrony by real time three-dimensional echocardiography (RT3DE) in patients with CCAVB and its association with LV dysfunction. In addition, we evaluated the agreement between RT3DE and tissue Doppler imaging (TDI) for detecting LV dyssynchrony. METHOD: We studied 50 patients [median age 20 years old (5 months to 62 years), 68% women] with CCAVB and pacemaker who underwent complete two-dimensional echocardiography and RT3DE. LV dyssynchrony was considered if the systolic dyssynchrony index (SDI) was ≥ 5%. Intraventricular mechanical delay was defined by TDI when differences in electromechanical activation between LV walls were > 65 msec. RESULTS: LV systolic dysfunction was present in 16 patients (32%) by two-dimensional and in 20 patients (40%) by RT3DE. There was a good correlation between LV ejection fraction by two-dimensional and RT3DE (r = 0.75; P < 0.001). Fourteen (28%) patients had intraventricular dyssynchrony by TDI, while 12 (24%) had intraventricular dyssynchrony by RT3DE. There was a good agreement between LV dyssynchrony by TDI and RT3DE (Kappa = 0.735; P < 0.001). There was a negative correlation between LV ejection fraction and SDI obtained by RT3DE (r = -0.58; P < 0.001) CONCLUSIONS: In patients with CCAVB and long-term pacing, LV dyssynchrony occurred in one-third of patients and was related to LV dysfunction. There was a good correlation between dyssynchrony obtained by RT3DE and TDI.


Subject(s)
Atrioventricular Block/diagnostic imaging , Atrioventricular Block/therapy , Cardiac Pacing, Artificial , Echocardiography, Three-Dimensional , Heart Block/congenital , Ventricular Dysfunction, Left/diagnostic imaging , Adolescent , Adult , Atrioventricular Block/complications , Child , Child, Preschool , Comorbidity , Female , Heart Block/complications , Heart Block/diagnostic imaging , Heart Block/therapy , Heart Ventricles/diagnostic imaging , Humans , Infant , Male , Middle Aged , Prevalence , Ventricular Dysfunction, Left/complications , Young Adult
7.
Genome ; 57(1): 1-8, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24564210

ABSTRACT

Phyllomys (Echimyidae, Rodentia) is a genus of Neotropical rodents with available cytogenetic data restricted to six out of 13 species, mainly based on simple staining methods, without detailed analyses. In this work, we present new karyotypes for Phyllomys lamarum (diploid number 2n = 56, fundamental number or number of autosomal arms FN = 102) and Phyllomys sp. (2n = 74, FN = 140) from the state of Minas Gerais, southeastern Brazil. We provide the first GTG- and CBG-banding patterns, silver-staining of the nucleolar organizer regions (Ag-NORs), and fluorescence in situ hybridization (FISH) with telomeric and 45S rDNA probes of Phyllomys. In addition to examining their chromosomes and phenotypic characters, we sequenced mitochondrial DNA from the specimens analyzed to confirm their taxonomic identification. The comparison of the distinctive chromosome complements of our specimens with those of other species of Phyllomys already published allowed us to conclude that chromosome data may be very useful for the taxonomy of the genus, as no two species analyzed presented the same diploid and fundamental numbers (2n and FN).


Subject(s)
Cytogenetic Analysis/methods , Karyotype , Rodentia/classification , Rodentia/genetics , Animals , Brazil , Chromosome Banding , Chromosomes, Mammalian/genetics , DNA, Mitochondrial/genetics , Evolution, Molecular , Female , In Situ Hybridization, Fluorescence , Male , Phylogeny , Rats , Sequence Analysis, DNA
8.
Pacing Clin Electrophysiol ; 36(12): 1539-49, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24117856

ABSTRACT

BACKGROUND: Although several studies have demonstrated deleterious consequences of chronic right ventricular (RV) pacing on ventricular function and synchronicity, its effects on health-related quality of life (HRQoL) and functional exercise capacity remain uncertain. We aimed to evaluate the effect of RV pacing on HRQoL and functional capacity of children and young adults with congenital complete atrioventricular block (CCAVB). METHODS: We included 66 consecutive subjects with RV cardiac pacemaker due to CCAVB and under clinical follow-up for more than 1 year. Multidimensional HRQoL scores were evaluated by Short Form-36 Health Survey (SF-36) and Child Health Questionnaire-Parent Form 50 (CHQ-PF50). Functional capacity was tested by a 6-minute walk distance test (6MWDT). Association analysis was performed to examine if any demographic and clinical characteristics were associated with lower HRQoL scores and shorter distances at the 6MWDT. RESULTS: Domains presenting lower HRQoL scores were vitality (64.0 ± 17.3), mental health (67.3 ± 8.0), role emotional (69.7 ± 35.8) in the SF-36 questionnaire; general health perceptions (61.3 ± 8.3), general behavior (61.9 ± 15.6), parental impact-emotional (67.7 ± 28.7) in the CHQ-PF50. Female gender (P = 0.009), left ventricular ejection fraction lower than 55% (P = 0.013), cardiovascular drugs (P = 0.003) were significantly associated with lower HRQoL scores. Average distance traveled during the 6MWDT was 539.8 ± 82.9 m. The 6MWDT showed significant association with age (P = 0.006) and cardiovascular drugs (P = 0.024). CONCLUSIONS: Chronic RV pacing did not affect the HRQoL and physical capacity of pediatrics and young subjects. Female gender, ventricular function, and cardiovascular drugs were associated with lower HRQoL scores. Older subjects walked shorter distances in the 6MWDT, as well as subjects who were taking cardiovascular drugs.


Subject(s)
Atrioventricular Block/congenital , Atrioventricular Block/psychology , Cardiac Pacing, Artificial/methods , Cardiac Pacing, Artificial/psychology , Quality of Life/psychology , Recovery of Function , Adolescent , Age Distribution , Atrioventricular Block/prevention & control , Child , Child, Preschool , Female , Heart Ventricles , Humans , Infant, Newborn , Longitudinal Studies , Male , Sex Distribution , Treatment Outcome , Young Adult
9.
Heart Rhythm ; 10(11): 1646-52, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23920077

ABSTRACT

BACKGROUND: Limited venous access in certain patients increases the procedural risk and complexity of conventional transvenous pacemaker implantation. OBJECTIVE: The purpose of this study was to determine a minimally invasive epicardial approach using pericardial reflections for dual-chamber pacemaker implantation in patients with limited venous access. METHODS: Between June 2006 and November 2011, 15 patients underwent epicardial pacemaker implantation. Procedures were performed through a minimally invasive subxiphoid approach and pericardial window with subsequent fluoroscopy-assisted lead placement. Mean patient age was 46.4 ± 15.3 years (9 male [(60.0%], 6 female [40.0%]). The new surgical approach was used in patients determined to have limited venous access due to multiple abandoned leads in 5 (33.3%), venous occlusion in 3 (20.0%), intravascular retention of lead fragments from prior extraction in 3 (20.0%), tricuspid valve vegetation currently under treatment in 2 (13.3%), and unrepaired intracardiac defects in 2 (13.3%). RESULTS: All procedures were successful with no perioperative complications or early deaths. Mean operating time for isolated pacemaker implantation was 231.7 ± 33.5 minutes. Lead placement on the superior aspect of right atrium, through the transverse sinus, was possible in 12 patients. In the remaining 3 patients, the atrial lead was implanted on the left atrium through the oblique sinus, the postcaval recess, or the left pulmonary vein recess. None of the patients displayed pacing or sensing dysfunction, and all parameters remained stable throughout the follow-up period of 36.8 ± 25.1 months. CONCLUSION: Epicardial pacemaker implantation through pericardial reflections is an effective alternative therapy for those patients requiring physiologic pacing in whom venous access is limited.


Subject(s)
Atrioventricular Block/therapy , Minimally Invasive Surgical Procedures/methods , Pacemaker, Artificial , Adult , Aged , Atrioventricular Block/diagnosis , Atrioventricular Block/physiopathology , Echocardiography , Electrocardiography , Female , Follow-Up Studies , Humans , Male , Middle Aged , Pericardium , Retrospective Studies , Stroke Volume , Treatment Outcome
10.
PLoS One ; 8(7): e71090, 2013.
Article in English | MEDLINE | ID: mdl-23936257

ABSTRACT

BACKGROUND: The ability to apply standard and interoperable solutions for implementing and managing medical registries as well as aggregate, reproduce, and access data sets from legacy formats and platforms to advanced standard formats and operating systems are crucial for both clinical healthcare and biomedical research settings. PURPOSE: Our study describes a reproducible, highly scalable, standard framework for a device registry implementation addressing both local data quality components and global linking problems. METHODS AND RESULTS: We developed a device registry framework involving the following steps: (1) Data standards definition and representation of the research workflow, (2) Development of electronic case report forms using REDCap (Research Electronic Data Capture), (3) Data collection according to the clinical research workflow and, (4) Data augmentation by enriching the registry database with local electronic health records, governmental database and linked open data collections, (5) Data quality control and (6) Data dissemination through the registry Web site. Our registry adopted all applicable standardized data elements proposed by American College Cardiology / American Heart Association Clinical Data Standards, as well as variables derived from cardiac devices randomized trials and Clinical Data Interchange Standards Consortium. Local interoperability was performed between REDCap and data derived from Electronic Health Record system. The original data set was also augmented by incorporating the reimbursed values paid by the Brazilian government during a hospitalization for pacemaker implantation. By linking our registry to the open data collection repository Linked Clinical Trials (LinkedCT) we found 130 clinical trials which are potentially correlated with our pacemaker registry. CONCLUSION: This study demonstrates how standard and reproducible solutions can be applied in the implementation of medical registries to constitute a re-usable framework. Such approach has the potential to facilitate data integration between healthcare and research settings, also being a useful framework to be used in other biomedical registries.


Subject(s)
Electronic Health Records/standards , Pacemaker, Artificial/statistics & numerical data , Registries/standards , Software , Brazil , Clinical Trials as Topic , Data Collection/standards , Electronic Health Records/statistics & numerical data , Humans , Pacemaker, Artificial/economics , Quality Control , Research Design
11.
Pacing Clin Electrophysiol ; 32 Suppl 1: S247-51, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19250106

ABSTRACT

BACKGROUND: The incidence of venous lesions following transvenous cardiac device implantation is high. Previous implantation of temporary leads ipsilateral to the permanent devices, and a depressed left ventricular ejection fraction have been associated with an increased risk of venous lesions, though the effects of preventive strategies remain controversial. This randomized trial examined the effects of warfarin in the prevention of these complications in high-risk patients. METHOD: Between February 2004 and September 2007, we studied 101 adults who underwent a first cardiac device implantation, and who had a left ventricular ejection fraction < or =0.40, or a temporary pacing system ipsilateral to the permanent implant, or both. After device implantation, the patients were randomly assigned to warfarin to a target international normalized ratio of 2.0-3.5, or to placebo. Clinical and laboratory evaluations were performed regularly up to 6 months postimplant. Venous lesions were detected at 6 months by digital subtraction venography. RESULTS: Venous obstructions of various degrees were observed in 46 of the 92 patients (50.0%) who underwent venography. The frequency of venous obstructions was 60.4% in the placebo, versus 38.6% in the warfarin group (P = 0.018), corresponding to an absolute risk reduction of 22% (relative risk = 0.63; 95% confidence interval = 0.013-0.42). CONCLUSIONS: Warfarin prophylaxis lowered the frequency of venous lesions after transvenous devices implantation in high-risk patients.


Subject(s)
Anticoagulants/therapeutic use , Electrodes/adverse effects , Venous Thrombosis/prevention & control , Warfarin/therapeutic use , Cardiac Pacing, Artificial/adverse effects , Comorbidity , Defibrillators, Implantable/adverse effects , Female , Follow-Up Studies , Humans , Incidence , Male , Middle Aged , Pacemaker, Artificial/adverse effects , Phlebography , Risk Factors , Treatment Outcome , Venous Thrombosis/epidemiology , Venous Thrombosis/etiology , Warfarin/administration & dosage
12.
Pacing Clin Electrophysiol ; 30 Suppl 1: S79-83, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17302724

ABSTRACT

BACKGROUND: Atrial fibrillation (AF) is a common complication after coronary artery bypass grafting (CABG). Since its prevention with prophylactic drug therapy has limited success, alternative approaches are desirable. This study examined the efficacy of atrial or biatrial pacing, compared with no pacing, on the incidence of AF after isolated CABG. METHODS: From August 2002 to September 2004, 240 patients underwent CABG. After surgery, right and left atrial epicardial pacing wires were implanted for 72 hours of temporary pacing. Patients were randomly assigned to one of three groups: no pacing (control group), right atrial (RA), and biatrial (BiA) pacing. Cardiac rhythm was monitored continuously during intensive care, or daily on the ward. The primary endpoints of this study were an episode of AF occurring up to 72 hours after CABG and the risk factors correlated with this event. RESULTS: Atrial and BiA pacing significantly lowered the incidence (1.25% vs 25%, P = 0.001) of AF episodes, and were both correlated (odd ratio 0.038; 95% confidence interval 0.005-0.29) with a decrease in rates of postoperative AF. Multivariable analysis identified older age (odd ratio 1.074; 95% confidence interval 1.024-1.12) and no pacing as independent risk factors of postoperative AF. CONCLUSIONS: Temporary right atrial or biatrial pacing after CABG significantly decreased the postoperative incidence of AF. Multivariable analysis identified older age and no pacing as predictors of AF occurrence.


Subject(s)
Atrial Fibrillation/prevention & control , Cardiac Pacing, Artificial/methods , Coronary Artery Bypass/adverse effects , Pacemaker, Artificial , Adult , Aged , Aged, 80 and over , Atrial Fibrillation/etiology , Female , Heart Atria , Humans , Male , Middle Aged , Risk Factors , Treatment Outcome
13.
J Microbiol Methods ; 54(2): 213-31, 2003 Aug.
Article in English | MEDLINE | ID: mdl-12782377

ABSTRACT

In this study, a Paenibacillus-specific PCR system, based on the specific primer PAEN515F in combination with bacterial primer R1401, was tested and used to amplify specific fragments of the 16S rRNA gene from rhizosphere DNA. The amplicons were used in a second (semi-nested) PCR for DGGE, in which bacterial primers F968GC and R1401 were used. The resulting products were separated into community fingerprints by DGGE. To assess the reliability of the method, the diversity of Paenibacillus species was evaluated on the basis of DNA extracted directly from the rhizospheres of four different cultivars of maize (Zea mays), i.e. CMS04, CMS11, CMS22 and CMS36, sown in two Brazilian field soils (Cerrado and Várzea). In addition, a clone library was generated from the PCR-generated 16S rDNA fragments, and selected clones were sequenced. The results of the bacterial community analyses showed, at the level of clone libraries, that considerable diversity among Paenibacillus spp. was present. The most dominantly found sequences clustered into 12 groups, each one potentially representing a species complex. Sequences closely affiliated with the P. macerans and P. azotofixans complexes were found in all samples, whereas other sequences were scarcer. Clones affiliated with the latter species complex were most abundant, representing 19% of all clones analysed. The Paenibacillus fingerprints generated via semi-nested PCR followed by DGGE showed a clear distinction between the maize plants grown in Cerrado versus Várzea soils. Thus, soil type, instead of maize cultivar type, was the overriding determinative factor that influenced the community structures of the Paenibacillus communities in the rhizospheres investigated. At a lower level (subcluster), there was a trend for maize cultivars CMS11 and CMS22 on the one hand, and CMS36 and CMS04 on the other hand, to cluster together, indicating that these respective pair of cultivars were similar in their Paenibacillus species composition. This trend was tentatively linked to the growth characteristics of these maize cultivars. These results clearly demonstrated the efficacy of the Paenibacillus-specific PCR-DGGE method in describing Paenibacillus species diversity in rhizosphere soils.


Subject(s)
DNA, Bacterial/analysis , Gram-Positive Endospore-Forming Rods/isolation & purification , Polymerase Chain Reaction , Zea mays/microbiology , Base Sequence , DNA Fingerprinting/methods , DNA, Bacterial/chemistry , Electrophoresis, Polyacrylamide Gel , Gram-Positive Endospore-Forming Rods/classification , Gram-Positive Endospore-Forming Rods/genetics , Nitrogen Fixation , Nucleic Acid Denaturation , Phylogeny , Plant Roots/microbiology , RNA, Ribosomal, 16S/analysis , RNA, Ribosomal, 16S/genetics , Reproducibility of Results , Research Design , Sequence Alignment
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