Insights into the local interaction mechanisms between fermenting broken maize and various binder materials for anaerobic digester structures.

Concrete structures of anaerobic digestion plants face chemically aggressive conditions due to the contact with the complex liquid fraction of the fermenting biowaste. This paper aims to determine the biogeochemical dynamic interaction phenomena at play between the biowaste and cementitious matrices at the local scale, and to identify durable binders in such environments. Binder materials likely to show increased durability - slag and calcium aluminate cement, and a metakaolin-based alkali-activated geopolymer - and a reference Portland cement were inserted into sealed bioeactors during 5 cycles (245 days) of broken maize anaerobic digestion. Cementitious pastes suffered chemical and mineralogical alteration related mainly to carbonation and leaching. However, they had no negative impact on the bioprocess in terms of pH, metabolic evolution of volatile fatty acids and NH4+, planktonic microbial community composition or CH4 production. In all reactors, the microbial community was able to perform the anaerobic digestion successfully. The MKAA was only slightly altered in its outermost layer. Its presence in the biowaste induced lower NH4+ concentrations, a slightly higher pH and a marked shift in the microbial community, but CH4 total production was not affected. Substantial enrichment of acid forming bacteria, especially members of the genus Clostridium, was observed in the biofilm formed on all materials.

One- vs 2-Stage Bursectomy for Septic Olecranon and Prepatellar Bursitis: A Prospective Randomized Trial.

OBJECTIVE: To assess the optimal surgical approach and costs for patients hospitalized with septic bursitis. PATIENTS AND METHODS: From May 1, 2011, through December 24, 2014, hospitalized patients with septic bursitis at University of Geneva Hospitals were randomized (1:1) to receive 1- vs 2-stage bursectomy. All the patients received postsurgical oral antibiotic drug therapy for 7 days. RESULTS: Of 164 enrolled patients, 130 had bursitis of the elbow and 34 of the patella. The surgical approach used was 1-stage in 79 patients and 2-stage in 85. Overall, there were 22 treatment failures: 8 of 79 patients (10%) in the 1-stage arm and 14 of 85 (16%) in the 2-stage arm (Pearson χ2 test; P=.23). Recurrent infection was caused by the same pathogen in 7 patients (4%) and by a different pathogen in 5 (3%). Outcomes were better in the 1- vs 2-stage arm for wound dehiscence for elbow bursitis (1 of 66 vs 9 of 64; Fisher exact test P=.03), median length of hospital stay (4.5 vs 6.0 days), nurses' workload (605 vs 1055 points), and total costs (Sw₣6881 vs Sw₣11,178; all P<.01). CONCLUSION: For adults with moderate to severe septic bursitis requiring hospital admission, bursectomy with primary closure, together with antibiotic drug therapy for 7 days, was safe, effective, and resource saving. Using a 2-stage approach may be associated with a higher rate of wound dehiscence for olecranon bursitis than the 1-stage approach. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT01406652.

Infectious olecranon and patellar bursitis: short-course adjuvant antibiotic therapy is not a risk factor for recurrence in adult hospitalized patients.

OBJECTIVES: No evidence-based recommendations exist for the management of infectious bursitis. We examined epidemiology and risk factors for recurrence of septic bursitis. Specifically, we compared outcome in patients receiving bursectomy plus short-course adjuvant antibiotic therapy (7 days). PATIENTS AND METHODS: Retrospective study of adult patients with infectious olecranon and patellar bursitis requiring hospitalization at Geneva University Hospital from January 1996 to March 2009. RESULTS: We identified 343 episodes of infectious bursitis (237 olecranon and 106 patellar). Staphylococcus aureus predominated among the 256 cases with an identifiable pathogen (85%). Three hundred and twelve cases (91%) were treated surgically; 142 (41%) with one-stage bursectomy and closure and 146 with two-stage bursectomy. All received antibiotics for a median duration of 13 days with a median intravenous component of 3 days. Cure was achieved in 293 (85%) episodes. Total duration of antibiotic therapy [odds ratio (OR) 0.9; 95% confidence interval (95% CI) 0.8-1.1] showed no association with cure. In multivariate analysis, only immunosuppression was linked to recurrence (OR 5.6; 95% CI 1.9-18.4). Compared with 14 days of antibiotic treatment (OR 0.9; 95% CI 0.1-10.7) was equivalent, as was the intravenous component (OR 1.1; 95% CI 1.0-1.3). CONCLUSIONS: In severe infectious bursitis requiring hospitalization, adjuvant antibiotic therapy might be limited to 7 days in non-immunosuppressed patients.