A functional collagen adhesin gene, acm, in clinical isolates of Enterococcus faecium correlates with the recent success of this emerging nosocomial pathogen.

Enterococcus faecium recently evolved from a generally avirulent commensal into a multidrug-resistant health care-associated pathogen causing difficult-to-treat infections, but little is known about the factors responsible for this change. We previously showed that some E. faecium strains express a cell wall-anchored collagen adhesin, Acm. Here we analyzed 90 E. faecium isolates (99% acm(+)) and found that the Acm protein was detected predominantly in clinically derived isolates, while the acm gene was present as a transposon-interrupted pseudogene in 12 of 47 isolates of nonclinical origin. A highly significant association between clinical (versus fecal or food) origin and collagen adherence (P

Predictors of benzodiazepine self -administration behavior in anxious patients

The purpose of this study was to examine factors that may be associated with benzodiazepine (BZ) self-administration and risks of dependence in anxious patients. Preliminary work included examination of psychosocial characteristics and subjective drug response as potential predictors of medication use. Fifty-five M, F patients with generalized anxiety or panic disorder participated in a 3-week outpatient Choice Procedure in which they self-medicated “as needed” with alprazolam (Alz) and placebo. Findings showed that a large amount of variance in alprazolam preference, frequency, and quantity of use could be predicted by measures of anxiety, drug liking, and certain personality characteristics. The primary study extended this work by examining whether individual differences in Alz sensitivity also predict patterns of use. Twenty anxious patients participated in the study, which required 11 weekly clinic visits. Ten of these also participated in a baseline assessment of HPA-axis function that involved 24-hour monitoring of cortisol and ACTH levels and a CRH Stimulation Test. This assessment was conducted on the basis of prior evidence that steroid metabolites exert neuromodulatory effects on the GABA A receptor and that HPA-axis function may be related to BZ sensitivity and long-term disability in anxious patients. Patients were classified as either HIGH or LOW users based on their p.r.n. patterns of Alz use during the first 3 weeks of the study. They then participated in a 4-week dose response trial in which they received prescribed doses of medication (placebo, 0.25, 0.5, and 1.0mg Alz), each taken TID for 1 week. The dose response trial was followed by a second 3-week Choice Procedure. Findings were not indicative of biological differences in Alz sensitivity between the HIGH and LOW users. However, the HIGH users had higher baseline anxiety and greater anxiolytic response to Alz than the LOW users. Anxiolytic benefits of p.r.n. and prescribed dosing were shown to be comparable, and patients' conservative patterns of p.r.n. medication use were not affected by the period of prescribed dosing. Although there was not strong evidence to suggest relationships between HPA-axis function and Alz use or sensitivity, interesting findings emerged about the relationship between HPA-axis function and anxiety. ^