Microbiome-preserving antibiotics for the treatment of Clostridioides difficile infection: a systematic review and meta-analysis.

BACKGROUND: Newer antibiotics that specifically target Clostridioides difficile while preserving the host microbiome have emerged to treat C. difficile infection (CDI): cadazolid, fidaxomicin, ridinilazole, and surotomycin. The aim of the present study was to perform a systematic review and meta-analysis of efficacy for each antibiotic. METHODS: Only randomized clinical trials of patients being treated for Clostridioides disease infection were included. Studies were sought in MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, ClinicalTrials.gov, and the World Health Organization clinical trials register portal (up to December 9, 2022). Sustained clinical cure was the outcome of treatment comparison, defined as the resolution of diarrhea without recurrence. Vancomycin was the standard treatment comparator. Meta-analysis was performed for each antibiotic. The overall certainty of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE)-classified as either high, moderate, low, or very low. RESULTS: Fourteen eligible studies were included in the meta-analysis with 4837 patients from 773 sites. Cadazolid did not increase sustained clinical cure relative to vancomycin (risk ratio (RR) 1.04, 95% confidence intervals (CI) 0.96-1.13; moderate-certainty evidence). Fidaxomicin demonstrated a significant increase (RR 1.14, 95% CI 1.07-1.21; low-certainty evidence). In one phase 2 study, ridinilazole demonstrated a significant increase in sustained clinical cure (RR 1.71, 95% CI 1.01-2.91; very low-quality evidence). Surotomycin did not show significant improvement (RR 1.05, 95% CI 0.96-1.14; moderate-certainty evidence). CONCLUSIONS: Fidaxomicin (in seven studies) demonstrated significant improvement in achieving sustained clinical cure. A limitation of this study may that more studies are needed to compare fidaxomicin with other antibiotics.

Correction to: Cesarean delivery to prevent anal incontinence: a systematic review and meta-analysis.

The original article can be found online.

Antibiotic prophylaxis in colorectal surgery: are oral, intravenous or both best and is mechanical bowel preparation necessary?

BACKGROUND: The benefit of adding oral antibiotic prophylaxis (OA) to intravenous prophylaxis (IV) in elective colorectal surgery to prevent surgical site infection (SSI) and whether the benefit of OA requires a mechanical bowel cleansing (MBP) are assessed in a systematic review. Meta-analyses compare randomized trials of IV versus IV plus OA, both with MBP; OA versus IV plus OA, both again with MBP; OA plus IV in studies randomizing patients to MBP or no MBP; and IV versus IV plus OA in patients with no MBP. METHODS: MEDLINE, EMBASE, and the Cochrane Library were searched for eligible studies from 1965 to April 1, 2020. The outcome assessed was SSI, superficial and deep, but not organ space. For each included study, risk of bias was assessed using the Cochrane Risk of Bias tool version 1. For each comparison, meta-analysis was performed from data from eligible studies to obtain a summary effect and heterogeneity using RevMan. Sensitivity analyses were performed excluding studies of poor quality. Certainty of evidence was assessed using GRADE for each comparison. RESULTS: Sixty-one studies published in 1971-2020 from 55 publications reporting 12,297 patients were eligible for inclusion. A total of 36 studies compared IV to OA plus IV with MBP. The risk ratio (RR) and 95% confidence interval (CI) for SSI with oral and IV vs. IV alone are 0.47, 0.40-0.56. The RR in 19 studies for IV plus OA versus OA alone is 0.48, 0.38-0.62. The RR for OA plus IV with MBP versus without MBP in 5 studies is 1.17, 0.84-1.64. The RR for OA plus IV versus IV alone when no bowel prep was used in two studies is 0.36, 0.18-0.72. RRs were similar in sensitivity analyses. The GRADE is high for the first two comparisons, moderate for the 3rd, and low for the 4th due to imprecision and heterogeneity. CONCLUSIONS: Combined OA and IV is superior to either alone in preventing SSI. The certainty of evidence is such that further research is unlikely to alter this relationship when MBP is used. In randomized trials of MBP, OA plus IV shows no benefit from MBP versus no MBP. The last comparison shows in just two studies that as in the first meta-analysis, but in the absence of MBP, combined OA plus IV is also superior to IV alone.

Cesarean delivery to prevent anal incontinence: a systematic review and meta-analysis.

BACKGROUND: Cesarean delivery (CD), is increasingly recommended as a mode of delivery that prevents the anal incontinence (AI) that arises in some women after vaginal delivery (VD). The assessment of the efficacy of CD in this regard was the subject of this systematic review. METHODS: Searches were conducted in Medline, EMBASE and the Cochrane Library. Both randomized (RCTs) and non-randomized trials (NRTs) comparing the risk of sustained fecal and/or flatus incontinence after VD or CD were sought from 1966 to 1 January, 2019. Studies were eligible if they assessed AI more than 6 months after birth, and had statistical adjustment for at least one of the three major confounders for AI: age, maternal weight or parity. In addition, each study was required to contain more than 250 participants, more than 50 CDs and more than 25 cases of AI. Data after screening and selection were abstracted and entered into Revman for meta-analysis. Analyses were done for combined fecal and flatus incontinence (comAI), fecal incontinence (FI), gas incontinence (GI), CD before or during labor, time trend of incontinence after delivery, assessment of both statistical and clinical heterogeneity, parity and late incident AI. RESULTS: Out of the 2526 titles and abstracts found, 24 eligible studies were analyzed, 23 NRTs and one RCT. These included women with 29,597 VDs and women with 6821 CDs. Among the primary outcomes, VD was found not to be a significant predictor of postpartum comAI compared to CD in 6 studies, incorporating 18,951 deliveries (OR = 0.74; 0.54-1.02). VD was also not a significant predictor of FI in 14 studies, incorporating 29,367 deliveries, (OR = 0.89; 0.76-1.05). VD was not a significant predictor of GI in six studies, incorporating 6724 deliveries (OR = 0.96; 0.79-1.18). The strength of the grading of recommendations, assessment, development and evaluations (GRADE) evidence for each of these was low for comAI and moderate for FI and GI (upgrade for lack of expected effect). Time trend FI showed incontinence at 3 months often resolved at 1 year. Other secondary analyses assessing parity, delayed incidence of FI, clinical and statistical heterogeneity, spontaneous VD only, late risk of incidence of AI, and CD in or prior to labor all had similar results as in the primary outcomes. CONCLUSIONS: There are three components of pelvic floor dysfunction that are thought to be caused by VD and hopefully prevented by CD: AI, urinary incontinence and pelvic floor prolapse. Of these, AI was not found to be reliably prevented by CD in this review.

Introgression of novel genetic diversity to improve soybean yield.

KEY MESSAGE: Exotic soybean germplasm can be used to increase novel genetic diversity and yield potential of cultivars. Modern North American soybean (Glycine max [L.] Merr.) cultivars have been derived from only a few ancestors. The objectives of this research were to develop breeding lines with novel genetic diversity that were equivalent to the yield of a commercial cultivar parent and within those lines identify regions of novel genetic diversity that were not present in the Corteva Agriscience elite soybean germplasm pool. Nine lines created from diverse germplasm (USDA-ARS breeding program at the University of Illinois) were crossed to a RM34Elite parent to develop populations and sublines for yield testing. Across yield tests at 30 locations conducted between 2014 and 2016, eleven breeding lines were identified that were equivalent to or significantly higher in yield when compared to the RM34Elite parent. Among the eleven final lines, the introgressed novel haplotypes that were not present in current Corteva Agriscience soybean germplasm occupied an estimated 0.8-10.0% of the genome. JH-2665, the highest yielding line across 3 years of testing, yielded 280 kg/ha more than the RM34Elite parent and had an estimated 8.6% of the genome containing novel diversity haplotypes. JH-2665 had 96 regions of novel diversity introgression ranging from 1 to 12 cM in size, with six regions over 6 cM in length. The methods reported demonstrate how high-yielding lines with novel genetic diversity can be developed. This material will be useful for expanding the genetic diversity needed to improve genetic gain in future soybean cultivar development.

Correction to: Topical antimicrobial prophylaxis in colorectal surgery for the prevention of surgical wound infection: a systematic review and meta-analysis.

Unfortunately, an author name (Nuzhat Iqbal) was missed out in the original publication. The complete updated author list is given below.

Topical antimicrobial prophylaxis in colorectal surgery for the prevention of surgical wound infection: a systematic review and meta-analysis.

BACKGROUND: Among the techniques investigated to reduce the risk of surgical wound infection or surgical space infection (SSI) in patients having colorectal surgery are topical application of antimicrobials (antibiotics and antiseptics) to the open wound or immediately after closure. The aim of the present study was to perform a systematic review of the literature on those treatments, with the exception of antibiotic ointments applied to closed skin, which are adequately assessed elsewhere, and a meta-analysis. METHODS: Only randomized trials of patients having only colorectal surgery were included in this review. Studies were sought in MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, Clinical Trials.gov, and the World Health Organization Internet clinical trials register portal. In addition, reference lists of included studies and other published reviews were screened. Meta-analysis was performed for all included studies and subgroup analyses done for each individual intervention. Risk of bias was assessed for each included study, paying particular attention to the preoperative antibiotic prophylaxis used in each study. Sensitivity analyses were done to investigate heterogeneity of the analyses, excluding those studies with a significant risk of bias issues. Absolute risk reduction (RR) was calculated. The overall quality of the evidence for each individual intervention was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, and was classified as high, moderate, low or very low. RESULTS: A total of 30 studies are included in this review with 5511 patients, 665 of whom had SSI. The interventions included: 10 studies of gentamicin impregnated sponge or beads wound inlays, 4 studies of chlorhexidine impregnated suture, 11 studies of direct wound lavage or powder application or injection of antibiotics before closure, 4 studies of ionized silver dressing applied to the closed skin, and 1 study of vitamin E oil applied to the open wound. All but one study used preoperative antibiotic prophylaxis in addition to topical procedures, although, in some studies, the systemic antibiotic prophylaxis was not the same between groups or varied significantly from the recommended guidelines. Use of gentamycin sponge did not decrease SSI (RR 0.93, 95% CI 0.75-1.16; low-quality evidence) even after including only the studies of abdominal wounds (RR 1.02, 95% CI 0.80-1.30; low-quality evidence). However, sensitivity analysis excluding studies at high risk of bias decreased the heterogeneity and increased the effect of the prophylaxis for all wounds (RR 0.5, 95% CI 0.33-0.78; low-quality evidence) and for abdominal wounds only (RR 0.38, 95% CI 0.20-0.72; moderate-quality evidence). Chlorhexidine impregnated suture showed no effect on SSI (RR 0.79, 95% CI 0.56-1.10; low-quality evidence) and an increased efficacy after sensitivity analysis (RR 0.42, 95% CI 0.22-0.79; low-quality evidence). Antibiotic lavage showed a significant decrease in SSI (RR 0.45, 95% CI 0.26-0.79; low-quality evidence) which increased after sensitivity analysis (RR 0.33, 95% CI 0.15-0.72; moderate-quality evidence). Application of silver dressing to the closed wound resulted in a decrease of SSI (RR 0.55, 95% CI 0.35-0.85; moderate-quality evidence). The one study of topical vitamin E oil applied to the open wound showed a significant risk reduction (RR 0.22, 95% CI 0.05-0.98; low-quality evidence). CONCLUSIONS: Each of these interventions appears to be effective in decreasing SSI, but the number of studies for each is small and the quality of evidence is very low to moderate. Within the various outcomes of GRADE assessment, even a moderate classification suggests that further studies may well have very different results.. No randomized trials exist of combinations of two or more of the above interventions to see if there is a combined effect. Future studies should make sure that the antibiotic used preoperatively is uniform within a study and is consistent with the current guidelines. Deviation from this leads to a significant heterogeneity and risk of bias.

A systematic review and meta-analysis of the treatment of anal fissure.

BACKGROUND: Anal fissure has a very large number of treatment options. The choice is difficult. In an effort to assist in that, choice presented here is a systematic review and meta-analysis of all published treatments for anal fissure that have been studied in randomized controlled trials. METHODS: Randomized trials were sought in the Cochrane Controlled Trials Register, Medline, EMBASE and the trials registry sites clinicaltrials.gov and who/int/ictrp/search/en. Abstracts were screened, full-text studies chosen, and finally eligible studies selected and abstracted. The review was then divided into those studies that compared two or more surgical procedures and those that had at least one arm that was non-surgical. Studies were further categorized by the specific interventions and comparisons. The outcome assessed was treatment failure. Negative effects of treatment assessed were headache and anal incontinence. Risk of bias was assessed for each study, and the strength of the evidence of each comparison was assessed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. RESULTS: One hundred and forty-eight eligible trials were found and assessed, 31 in the surgical group and 117 in the non-surgical group. There were 14 different operations described in the surgical group and 29 different non-surgical treatments in the non-surgical group along with partial lateral internal sphincterotomy (LIS). There were 61 different comparisons. Of these, 47 were reported in 2 or fewer studies, usually with quite small patient samples. The largest single comparison was glyceryl trinitrate (GTN) versus control with 19 studies. GTN was more effective than control in sustained cure (OR 0.68; 95% CI 0.63-0.77), but the quality of evidence was very poor because of severe heterogeneity, and risk of bias due to inadequate clinical follow-up. The only comparison to have a GRADE quality of evidence of high was a subgroup analysis of LIS versus any medical therapy (OR 0.12; CI 0.07-0.21). Most of the other studies were downgraded in GRADE due to imprecision. CONCLUSIONS: LIS is superior to non-surgical therapies in achieving sustained cure of fissure. Calcium channel blockers were more effective than GTN and with less risk of headache, but with only a low quality of evidence. Anal incontinence, once thought to be a frequent risk with LIS, was found in various subgroups in this review to have a risk between 3.4 and 4.4%. Among the surgical studies, manual anal stretch performed worse than LIS in the treatment of chronic anal fissure in adults. For those patients requiring surgery for anal fissure, open LIS and closed LIS appear to be equally efficacious, with a moderate GRADE quality of evidence. All other GRADE evaluations of procedures were low to very low due mostly to imprecision.

Genetic architecture of cyst nematode resistance revealed by genome-wide association study in soybean.

BACKGROUND: Bi-parental mapping populations have been commonly utilized to identify and characterize quantitative trait loci (QTL) controlling resistance to soybean cyst nematode (SCN, Heterodera glycines Ichinohe). Although this approach successfully mapped a large number of SCN resistance QTL, it captures only limited allelic diversity that exists in parental lines, and it also has limitations for genomic resolution. In this study, a genome-wide association study (GWAS) was performed using a diverse set of 553 soybean plant introductions (PIs) belonging to maturity groups from III to V to detect QTL/genes associated with SCN resistance to HG Type 0. RESULTS: Over 45,000 single nucleotide polymorphism (SNP) markers generated by the SoySNP50K iSelect BeadChip (http// www.soybase.org ) were utilized for analysis. GWAS identified 14 loci distributed over different chromosomes comprising 60 SNPs significantly associated with SCN resistance. Results also confirmed six QTL that were previously mapped using bi-parental populations, including the rhg1 and Rhg4 loci. GWAS identified eight novel QTL, including QTL on chromosome 10, which we have previously mapped by using a bi-parental population. In addition to the known loci for four simple traits, such as seed coat color, flower color, pubescence color, and stem growth habit, two traits, like lodging and pod shattering, having moderately complex inheritance have been confirmed with great precision by GWAS. CONCLUSIONS: The study showed that GWAS can be employed as an effective strategy for identifying complex traits in soybean and for narrowing GWAS-defined genomic regions, which facilitates positional cloning of the causal gene(s).

Intersubgeneric hybridization between Glycine max and G. tomentella: production of F1, amphidiploid, BC1, BC2, BC3, and fertile soybean plants.

KEY MESSAGE: This paper describes methods for unlocking genetic treasure from wild perennial Glycine species of Australia for soybean improvement. The genetic resources of the ca. 26 species of the genus Glycine subgenus Glycine have not been exploited to broaden the genetic base of soybean (Glycine max; 2n = 40). The objectives of this study were to develop methods for producing F1, amphidiploid, BC1, BC2, BC3, and fertile soybean plants from crosses of soybean and the genus Glycine subgenus Glycine species, in order to utilize the subgenus Glycine germplasm in soybean breeding. Soybean cultivars were hybridized with six accessions of 78-chromosome G. tomentella as well as one accession each of 40-chromosome G. tomentella, G. argyrea and G. latifolia. They were chosen because they exhibit resistance to soybean rust. We were successful in producing fertile soybean from soybean cv. 'Dwight' and 78-chromosome G. tomentella accession PI 441001, while other hybrids were discontinued either at F1 or amphidiploid stage. The F1 seeds aborted prior to reaching maturity, so developing seeds from 19 to 21 day old pods were cultured aseptically in various media formulations. Seed maturation and multiple embryo generation media were developed. F1 plants with shoots and roots (2n = 59) were transplanted to pots in greenhouse. Amphidiploid (2n = 118) plants were backcrossed to 'Dwight'. BC1 (2n = 79) plants were propagated through in vitro and 43 mature BC2F1 seeds were harvested. Fifteen surviving BC2F1 plants were morphologically distinct, sterile, and had chromosome numbers ranging 2n = 56-59. Chromosome numbers of the BC3F1 plants ranged 2n = 40-49. Derived fertile soybeans were first planted in the field in 2008 and are being evaluated for yield, resistance to pathogens and pests and tolerance to salt through material transfer agreement.

Identification of positive yield QTL alleles from exotic soybean germplasm in two backcross populations.

Increasing seed yield is an important breeding goal of soybean [Glycine max (L.) Merr.] improvement efforts. Due to the small number of ancestors and subsequent breeding and selection, the genetic base of current soybean cultivars in North America is narrow. The objective of this study was to map quantitative trait loci (QTL) in two backcross populations developed using soybean plant introductions as donor parents. The first population included 116 BC(2)F(3)-derived lines developed using "Elgin" as the recurrent parent and PI 436684 as the donor parent (E population). The second population included 93 BC(3)F(3)-derived lines developed with "Williams 82" as the recurrent parent and PI 90566-1 as the donor parent (W population). The two populations were evaluated with 1,536 SNP markers and during 2 years for seed yield and other agronomic traits. Genotypic and phenotypic data were analyzed using the programs MapQTL and QTLNetwork to identify major QTL and epistatic QTL. In the E population, two yield QTL were identified by both MapQTL and QTLNetwork, and the PI 436684 alleles were associated with yield increases. In the W population, a QTL allele from PI 90566-1 accounted for 30 % of the yield variation; however, the PI region was also associated with later maturity and shorter plant height. No epistasis for seed yield was identified in either population. No yield QTL was previously reported at the regions where these QTL map indicating that exotic germplasm can be a source of new alleles that can improve soybean yield.

Surgical management of anal fistulae: a systematic review.

OBJECTIVE: The anal fistula has been a common surgical ailment reported since the time of Hippocrates but little systematic evidence exists on its management. We aimed to systematically review the available studies relating to the surgical management of anal fistulas. METHOD: Studies were identified from PubMED, EMBASE, Cochrane Controlled Trials Register, ClinicalTrials.Gov and Current Controlled Trials. All uncontrolled, nonrandomized, retrospective studies, duplications or those unrelated to the surgical management of anal fistulas were excluded. RESULTS: The search strategy revealed 443 trials. After exclusions 21 randomized controlled trials remained evaluating: fistulotomy vs fistulectomy (n = 2), seton treatment (n = 3), marsupialization (n = 2), glue therapy (n = 3), anal flaps (n = 3), radiosurgical approaches (n = 2), fistulotomy/fistulectomy at time of abscess incision (n = 5) and intra-operative anal retractors (n = 1). Two meta-analyses evaluating incision and drainage alone vs incision + fistulotomy were obtained. CONCLUSION: Marsupialization after fistulotomy reduces bleeding and allows for faster healing. Results from small trials suggest flap repair may be no worse than fistulotomy in terms of healing rates but this requires confirmation. Flap repair combined with fibrin glue treatment of fistulae may increase failure rates. Radiofrequency fistulotomy produces less pain on the first postoperative day and may allow for speedier healing. Major gaps remain in our understanding of anal fistula surgery.

Landmark research in legumes.

Legumes are members of the family Fabaceae or Leguminosae and include economically important grain legumes, oilseed crops, forage crops, shrubs, and tropical or subtropical trees. Legumes are a rich source of quality protein for humans and animals. They also enrich the soil by producing their own nitrogen in symbiosis with nitrogen-fixing bacteria. International centers and national institutes collect, maintain, distribute, and produce high-yielding legumes (grain-pulses, oilseeds, forages, nutraceuticals, medicinal shrubs, and trees). Legume breeders are confined within the primary gene pools (GP-1) in their varietal improvement programs and have not exploited secondary gene pools (GP-2), tertiary gene pools (GP-3), or quaternary gene pools (GP-4). Legumes are also an excellent source of timber, medicine, nutraceuticals, tannins, gums, insecticides, resins, varnish, paints, dyes, and eco-friendly by-products such as soy diesel. Three forage crops, Medicago truncatula, Lotus japonicus, and Trifolium pratense, are model legumes for phylogenetic studies and genome sequencing. This paper concludes that a "protein revolution" is needed to meet the protein demands of the world.

Surgery for faecal incontinence in adults.

BACKGROUND: Faecal incontinence is a debilitating problem with significant medical, social and economic implications. Treatment options include conservative, non-surgical interventions (e.g. pelvic floor muscle training, biofeedback, drugs, sacral nerve stimulation) and surgical procedures. A surgical procedure may be aimed at correcting an obvious mechanical defect, or augmenting a functionally deficient but structurally intact sphincter complex or replace an absent/non-functioning sphincter. OBJECTIVES: To assess the effects of surgical techniques for the treatment of faecal incontinence in adults who do not have rectal prolapse. Our aim was firstly to compare surgical management with non-surgical management and secondly, to compare the various surgical techniques. SEARCH STRATEGY: We searched the Cochrane Incontinence Group Specialised Trials Register (31 January 2006), the Cochrane Colorectal Cancer Group trials register (31 January 2006), the Cochrane Central Register of Controlled Trials (2006, Issue 1), PubMed (1 January 1950 to 31 January 2006) and EMBASE (1 January 1998 to 31 January 2006) were undertaken. The British Journal of Surgery (January 1995 to May 2006) Colorectal Diseases (January 2000-May 2006) and the Diseases of the Colon and Rectum (January 1995 to May 2006) were specifically handsearched. The proceedings of the Association of Coloproctology meeting held from 1999 to 2006 were perused. Reference lists of all relevant articles were searched for further trials. SELECTION CRITERIA: All randomised or quasi-randomised trials of surgery in the management of adult faecal incontinence (other than surgery for rectal prolapse). DATA COLLECTION AND ANALYSIS: Two reviewers independently selected studies from the literature searches, assessed the methodological quality of eligible trials and extracted data. The three primary outcome measures were: change or deterioration in incontinence, failure to achieve full continence, and the presence of faecal urgency. MAIN RESULTS: Nine trials were included with a total sample size of 264 participants. Two trials included a group managed non-surgically. One trial compared levatorplasty with anal plug stimulation, one compared artificial bowel sphincter with best supportive care; numbers were small in both trials. The artificial bowel sphincter insertion was followed by significant improvements in at least one primary outcome but with high rates of significant morbidity. Seven studies compared different surgical interventions. These included anterior levatorplasty versus postanal repair, anterior levatorplasty versus total pelvic floor repair, total pelvic floor versus postanal repair, end to end versus overlap sphincter repair, overlap repair with or without a defunctioning stoma or with or without biofeedback, total pelvic floor repair versus repair plus internal sphincter plication and neosphincter formation versus total pelvic floor repair. Only one comparison had more that one trial (total pelvic floor versus postanal repair-44 participants) and no comparison showed any statistically significant difference in primary outcome measures, with wide confidence intervals. AUTHORS' CONCLUSIONS: Despite more studies being included in this update, the continued small number of relevant trials identified together with their small sample sizes and other methodological weaknesses continue to limit the usefulness of this review for guiding practice. It was impossible to identify or refute clinically important differences between the alternative surgical procedures. Larger rigorous trials are still needed. However, it should be recognised that the optimal treatment regime may be a complex combination of various surgical and non-surgical therapies.

Free-air carbon dioxide enrichment of soybean: influence of crop variety on residue decomposition.

Elevated atmospheric CO2 can result in larger plants returning greater amounts of residue to the soil. However, the effects of elevated CO2 on carbon (C) and nitrogen (N) cycling for different soybean varieties have not been examined. Aboveground residue of eight soybean [Glycine max (L.) Merr.] varieties was collected from a field study where crops had been grown under two different atmospheric CO2 levels [370 micromol mol(-1) (ambient) and 550 micromol mol(-1) (free-air carbon dioxide enrichment, FACE)]. Senesced residue material was used in a 60-d laboratory incubation study to evaluate potential C and N mineralization. In addition to assessing the overall effects of CO2 level and variety, a few specific variety comparisons were also made. Across varieties, overall residue N concentration was increased by FACE, but residue C concentration was only slightly increased. Overall residue C to N ratio was lower under FACE and total mineralized N was increased by FACE, suggesting that increased N2 fixation impacted residue decomposition; total mineralized C was also slightly increased by FACE. Across CO2 levels, varietal differences were also observed with the oldest variety having the lowest residue N concentration and highest residue C to N ratio; mineralized N was lowest in the oldest variety, illustrating the influence of high residue C to N ratio. It appears (based on our few specific varietal comparisons) that the breeding selection process may have resulted in some varietal differences in residue quality which can result in increased N or C mineralization under elevated CO2 conditions. This limited number of varietal comparisons indicated that more work investigating varietal influences on soil C and N cycling under elevated CO2 conditions is required.

Response of Commercially Developed Soybean Cultivars and the Ancestral Soybean Lines to Fusarium solani f. sp. glycines.

Sudden death syndrome, caused by Fusarium solani f. sp. glycines, has caused severe damage to soybean production in recent years. One way to control sudden death syndrome is with resistant cultivars. Over a 3-year period, 2,335 publicly and privately developed soybean entries were inoculated and evaluated for their response to F. solani f. sp. glycines under greenhouse conditions. The entries were compared with the susceptible check, Great Lakes 3302 (GL3302), and the moderately resistant checks, plant introductions (PIs) 520733 and 567374. Thirty-eight entries were identified with moderate levels of resistance. Based on foliar ratings, there were no differences (P < 0.05) between the Roundup Ready and conventional cultivars. In all, 90 ancestral lines that represent 99% of the genes in modern U.S. cultivars and 55 lines found in the pedigrees of public cultivars reported to have some resistance were evaluated for their response to F. solani f. sp. glycines. Nine ancestral lines (Aoda, Kim, Jackson, Sioux, Mammoth Yellow, T117, PI 171450, PI 54615-1, and PI 71506) and 12 cultivars or experimental lines (Ina, D83-3349, LN98-4340, LN83-2356, Hartwig, Harosoy, Bedford, Merit, Cutler, Calland, Hill, and Evans) had disease ratings not significantly different (P < 0.05) from PI 520733 or PI 567374. PI 54610, a putative ancestral line, also was found to be moderately resistant.

Etiologia e evolução das meningites bacterianas em centro de pediatria / Etiology and evolution of bacterial meningitis in a pediatric center

Objetivo: determinar a prevalência dos agentes etiológicos das meningites bacterianas em serviço dereferência, no atendimento de doenças infecciosas para o estado de Minas Gerais, e verificar a resposta ao tratamento utilizado. Métodos: estudo descritivo em que foram incluídas todas as crianças com diagnóstico provável de meningite,admitidas na instituiçào no período de junho a novembro/99. Resultados: obteve-se 210 casos de meningite, sendo 111 casos de etiologia bacteriana (52,9 por cento). Destes, 52 casos foram diagnósticos prováveis ( por alteração do liquor rotina) e 59 com diagnósticos de certeza ( por cultura e/ou isolamento de antígeno). Os principais agentes isoldos foram, em ordem decrescente, H. influenzae, N. meningitidis e S. pneumoniae. O tratamento inicial para a faixa etária de três meses a cinco anos foi ampicilina e cloranfenicol, sendo posteriormente restrito para penicilina em casos de meningococo e pneumococo, e para cloranfenicol nos casos de H.influenzae. A mudança para antimicrobiano de maior espectro foi realizada com base em dados clínicos ou laboratoriais, não havendo isolamento de microorganismo resistente. Conclusões: o acompanhamento do perfil epidemiológico das meningites deve ser contínuo, e cada serviço deve se basear em dados locais para direcionar a terapia antimicrobiana. A monitorização contínua dos agentes prevalentes em cada instituição e de sua resistência é fundamental para a escolha antimicrobiana, atuando com menor interferência na colonização individual, sem contribuir para a crescente resistência dos agentes responsáveis pelas infecções meníngeas