Influence of environmental factors on the tropical peatlands diazotrophic communities from the Southern Brazilian Atlantic Rain Forest.

The tropical peatlands of southern Brazil are essential for the maintenance of the Atlantic Rain Forest, one of the 25 hotspots of biodiversity in the world. Although diazotrophic micro-organisms are essential for the maintenance of this nitrogen limited ecosystem, so far studies have focused only on micro-organisms involved in the carbon cycle. In this work, peat samples were collected from three tropical peatland regions during dry and rainy seasons and their chemical and microbial characteristics were evaluated. Our results showed that the structure of the diazotrophic communities in the Brazilian tropical peatlands differs in the evaluated seasons. The abundance of the genus Bradyrhizobium showed to be affected by rainfall and peat pH. Despite the shifts of the nitrogen-fixing population in the tropical peatland caused by seasonality it showed to be constantly dominated by α-Proteobacteria followed by Cyanobacteria. In addition, more than 50% of nifH gene sequences have not been classified, indicating the necessity for more studies in tropical peatland, since the reduction of N supply in the peatlands stimulates the recalcitrant organic matter decomposition performed by peatland micro-organisms, influencing the C stock.

Prokaryotic communities of acidic peatlands from the southern Brazilian Atlantic Forest

The acidic peatlands of southern Brazil are ecosystems essential for the maintenance of the Atlantic Forest, one of the 25 hot-spots of biodiversity in the world. In this work, we investigated the composition of prokaryotic communities in four histosols of three acidic peatland regions by constructing small-subunit (SSU) rRNA gene libraries and sequencing. SSU rRNA gene sequence analysis showed the prevalence of Acidobacteria (38.8%) and Proteobacteria (27.4%) of the Bacteria domain and Miscellaneous (58%) and Terrestrial (24%) groups of Crenarchaeota of the Archaea domain. As observed in other ecosystems, archaeal communities showed lower richness than bacterial communities. We also found a limited number of Euryarchaeota and of known methanotrophic bacteria in the clone libraries.

Prokaryotic communities of acidic peatlands from the southern Brazilian Atlantic Forest.

The acidic peatlands of southern Brazil are ecosystems essential for the maintenance of the Atlantic Forest, one of the 25 hot-spots of biodiversity in the world. In this work, we investigated the composition of prokaryotic communities in four histosols of three acidic peatland regions by constructing small-subunit (SSU) rRNA gene libraries and sequencing. SSU rRNA gene sequence analysis showed the prevalence of Acidobacteria (38.8%) and Proteobacteria (27.4%) of the Bacteria domain and Miscellaneous (58%) and Terrestrial (24%) groups of Crenarchaeota of the Archaea domain. As observed in other ecosystems, archaeal communities showed lower richness than bacterial communities. We also found a limited number of Euryarchaeota and of known methanotrophic bacteria in the clone libraries.

Drainage or nondrainage in elective colorectal anastomosis: a systematic review and meta-analysis.

BACKGROUND: There is little agreement on prophylactic use of drains in anastomoses in elective colorectal surgery despite many randomized clinical trials. Once anastomotic leakage occurs it is generally agreed that drains should be used for therapeutic purposes. However, on prophylactic use no such agreement exists. AIM: To compare the safety and effectiveness of routine drainage and nondrainage regimes after elective colorectal surgery. The primary outcome was clinical anastomotic leakage. METHODS: A systematic search was undertaken to identify randomized clinical trials. Of the 1140 patients who were enrolled (six randomized controlled trials), 573 were allocated for drainage and 567 for no drainage. Outcome measures were: (i) mortality: 3% (18 of 573 patients) compared with 4% (25 of 567 patients); (ii) clinical anastomotic dehiscence: 2% (11 of 522 patients) compared with 1% (7 of 519 patients); (iii) radiological anastomotic dehiscence: 3% (16 of 522 patients) compared with 4% (19 of 519 patients); (iv) wound infection: 5% (29 of 573 patients) compared with 5% (28 of 567 patients); (v) reintervention: 6% (34 of 542 patients) compared with 5% (28 of 539 patients); (vi) extra-abdominal complications: 7% (34 of 522 patients) compared with 6% (32 of 519 patients). None of these differences in outcome was significant. CONCLUSION: There is insufficient evidence showing that routine drainage after colorectal anastomoses prevents anastomotic and other complications.

Prophylactic anastomotic drainage for colorectal surgery.

BACKGROUND: There is little agreement on prophylactic use of drains in anastomoses in elective colorectal surgery despite many randomized clinical trials. Results of these trials are contradictory, quality and statistical power of these individual studies have been questioned. Once anastomotic leakage has occurred it is generally agreed that drains should be used for therapeutic purposes. However, on prophylactic use no such agreement exists. OBJECTIVES: Comparison of safety and effectiveness of routine drainage and non-drainage regimes after colorectal surgery. The following hypothesis was tested: The use of prophylactic anastomotic drainage after elective colorectal surgery does not prevent development of complications. SEARCH STRATEGY: The studies were identified from CINAHL, EMBASE, LILACS, MEDLINE, Controlled Clinical Trials Database, Trials Register of the Cochrane Colorectal Cancer Group, reference lists. SELECTION CRITERIA: Randomized controlled trials comparing drainage with non-drainage regimes after anastomoses in elective colorectal surgery were reviewed. Outcome measures were: 1. mortality; 2. clinical anastomotic dehiscence; 3. radiological anastomotic dehiscence; 4. wound infection; 5. reoperation; 6. extra-abdominal complications. DATA COLLECTION AND ANALYSIS: Data were independently extracted and cross-checked by the two reviewers. The methodological quality of each trial was assessed. Details of the randomization (generation and concealment), blinding, and the number of patients lost to follow-up were recorded. The RCTs were stratified based on experimental group, according to clinical homogeneity (external validity). MAIN RESULTS: Of the 1140 patients enrolled (6 RCTs), 573 were allocated for drainage and 567 for no drainage. The patients assigned to the drainage group compared with the ones assigned to non-drainage group showed: a) Mortality: 3% (18 of 573 patients) compared with 4% (25 of 567 patients); b) Clinical anastomotic dehiscence: 2% (11 of 522 patients) compared with 1% (7 of 519 patients); c) Radiological anastomotic dehiscence: 3% (16 of 522 patients) compared with 4% (19 of 519 patients); d) Wound infection: 5% (29 of 573 patients) compared with 5% (28 of 567 patients); e) Reintervention: 6% (34 of 542 patients) compared with 5% (28 of 539 patients); f) Extra abdominal complications: 7% (34 of 522 patients) compared with 6% (32 of 519 patients). REVIEWERS' CONCLUSIONS: There is insufficient evidence showing that routine drainage after colorectal anastomoses prevents anastomotic and other complications.