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Antibiotic Choices (antibiotic + choice)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Models for Estimating Bayes Factors with Applications to Phylogeny and Tests of Monophyly

BIOMETRICS, Issue 3 2005
Marc A. Suchard
Summary Bayes factors comparing two or more competing hypotheses are often estimated by constructing a Markov chain Monte Carlo (MCMC) sampler to explore the joint space of the hypotheses. To obtain efficient Bayes factor estimates, Carlin and Chib (1995, Journal of the Royal Statistical Society, Series B57, 473,484) suggest adjusting the prior odds of the competing hypotheses so that the posterior odds are approximately one, then estimating the Bayes factor by simple division. A byproduct is that one often produces several independent MCMC chains, only one of which is actually used for estimation. We extend this approach to incorporate output from multiple chains by proposing three statistical models. The first assumes independent sampler draws and models the hypothesis indicator function using logistic regression for various choices of the prior odds. The two more complex models relax the independence assumption by allowing for higher-lag dependence within the MCMC output. These models allow us to estimate the uncertainty in our Bayes factor calculation and to fully use several different MCMC chains even when the prior odds of the hypotheses vary from chain to chain. We apply these methods to calculate Bayes factors for tests of monophyly in two phylogenetic examples. The first example explores the relationship of an unknown pathogen to a set of known pathogens. Identification of the unknown's monophyletic relationship may affect antibiotic choice in a clinical setting. The second example focuses on HIV recombination detection. For potential clinical application, these types of analyses must be completed as efficiently as possible. [source]

Free tissue transfer in pregnancy: Guidelines for perioperative management

MICROSURGERY, Issue 5 2001
G. Robert Meger M.D.
A successful free tissue transfer of serratus anterior muscle, to provide coverage for an open ankle defect in a pregnant patient, is described. Microvascular surgery in the presence of a viable pregnancy demands considerations unique to this situation. Although rarely possible, an attempt should be made to plan surgery to coincide with the second trimester, to lessen the risk of anesthesia to the fetus. Maternal positioning, fluid balance, and aspiration precautions need to be critically addressed. Close perioperative monitoring by an obstetrician is essential. The condition of pregnancy results in a hypercoagulable state that may lead to an increased risk of anastomotic failure. The use of anticoagulants results in increased risk of bleeding, not only for the patient but also for the fetus, as well as risk of teratogenic effects. Closely monitored heparin is considered safe in pregnancy as is low-molecular-weight dextran and low-dose aspirin. Additional considerations include the use of narcotics and sedatives for comfort postoperatively, as well as antibiotic choices, if indicated. © 2001 Wiley-Liss, Inc. Microsurgery 21:202,207 2001 [source]

Have the Organisms that Cause Breast Abscess Changed With Time?,,Implications for Appropriate Antibiotic Usage in Primary and Secondary Care

THE BREAST JOURNAL, Issue 4 2010
Natalie Dabbas MBBS
Abstract:, Many patients with breast abscess are managed in primary care. Knowledge of current trends in the bacteriology is valuable in informing antibiotic choices. This study reviews bacterial cultures of a large series of breast abscesses to determine whether there has been a change in the causative organisms during the era of increasing methicillin-resistant Staphylococcus aureus (MRSA). Analysis was undertaken of all breast abscesses treated in a single unit over 2003 , 2006, including abscess type, bacterial culture, antibiotic sensitivity and resistance patterns. One hundred and ninety cultures were obtained (32.8% lactational abscess, 67.2% nonlactational). 83% yielded organisms. Staphylococcus aureus was the commonest organism isolated (51.3%). Of these, 8.6% were MRSA. Other common organisms included mixed anaerobes (13.7%), and anaerobic cocci (6.3%). Lactational abscesses were significantly more likely to be caused by S. aureus (p < 0.05). Methicillin-resistant Staphylococcus aureus rates were not statistically different between lactational and nonlactational abscess groups. Appropriate antibiotic choices are of great importance in the community management of breast abscess. Ideally, microbial cultures should be obtained to institute targeted therapy but we recommend the continued use of flucloxacillin with or without metronidazole (or amoxicillin-clavulanate as a single preparation) as initial empirical therapy. [source]