Efficient Detection of Carbapenemase Activity in Enterobacteriaceae by Matrix-Assisted Laser Desorption Ionization?Time of Flight Mass Spectrometry in Less Than 30 Minutes

The recognition of carbapenemase-producing Enterobacteriaceae (CPE) isolates is a major laboratory challenge, and their inappropriate or delayed detection may have negative impacts on patient management and on the implementation of infection control measures. We describe here a matrix-assisted laser desorption ionization−time of flight (MALDI-TOF)-based method to detect carbapenemase activity in Enterobacteriaceae. After a 20-min incubation of the isolate with 0.5 mg/ml imipenem at 37°C, supernatants were analyzed by MALDI-TOF in order to identify peaks corresponding to imipenem (300 Da) and an imipenem metabolite (254 Da). A total of 223 strains, 77 CPE (OXA-48 variants, KPC, NDM, VIM, IMI, IMP, and NMC-A) and 146 non-CPE (cephalosporinases, extended-spectrum β-lactamases [ESBLs], and porin defects), were tested and used to calculate a ratio of imipenem hydrolysis: mass spectrometry [MS] ratio = metabolite/(imipenem + metabolite). An MS ratio cutoff was statistically determined to classify strains as carbapenemase producers (MS ratio of ≥0.82). We validated this method first by testing 30 of our 223 isolates (15 CPE and 15 non-CPE) 10 times to calculate an intraclass correlation coefficient (ICC of 0.98), showing the excellent repeatability of the method. Second, 43 strains (25 CPE and 18 non-CPE) different from the 223 strains used to calculate the ratio cutoff were used as external controls and blind tested. They yielded sensitivity and specificity of 100%. The total cost per test is <0.10 U.S. dollars (USD). This easy-to-perform assay is time-saving, cost-efficient, and highly reliable and might be used in any routine laboratory, given the availability of mass spectrometry, to detect CPE.     

Methodology for evaluating the sustainability of products and processes: application to alternative substitution techniques of chromium VI

Faced with increasing regulatory and social pressures, the industrial world must offer safer and more environmentally services while maintaining economic competitiveness. Thus, the development of sustainable activities is essential, and new interactive approaches to evaluate them are needed. In this context, the purpose of this study is to develop a methodology to analyse and compare the sustainability of alternative designs and productions during the preliminary phase of a project considering several criteria based on environment, economy, health and safety risks, and obsolescence risks. This paper describes, on one hand, the proposed methodology used to evaluate each criterion separately and to obtain the final integrated score. On the other hand, it proposes the application of the methodology to the comparison of surface treatment processes used in aircraft industry, to illustrate and validate the approach. The case study is about the comparison of an electrochemical process for the treatment of aluminium against corrosion: chromic acid anodizing, and alternatives without chromium, tartaric sulphuric acid anodizing and boric sulphuric acid anodizing.     

Posttraumatic Stress Disorder and One‐Year Outcome in Methadone Maintenance Treatment

Background: Although opiate use may be associated with posttraumatic stress disorder (PTSD), it is not clear whether PTSD is associated with retention in methadone maintenance. Objectives: To evaluate among those receiving methadone maintenance at an urban methadone maintenance clinic the frequency of life‐time traumatic experiences, the predictors and prevalence of current PTSD, and whether PTSD affects retention at 1 year. Methods: Eighty‐nine people participated in the study. The Post Traumatic Diagnostic Scale was used to determine the prevalence of PTSD. The Life Stressor Checklist Revised was used to evaluate trauma history. Logistic regression analyses examined associations between demographic characteristics, substance use, trauma‐related variables, and PTSD. Similar logistic regression analyses were used to examine retention in methadone maintenance at 1 year. Results: The mean number of reported lifetime stressful events was 8.0 (SD = 3.7). Twenty‐seven percent were diagnosed with PTSD. Nearly 92% of those with PTSD had co‐occurring depressive symptoms. Female gender (adjusted odds ratio [AOR][95% CI]; 3.89 [1.07–14.01]), number of traumatic events (AOR [95% CI]; 1.34 [1.13–1.61]), and less education (AOR [95% CI]; 4.13 [1.14–14.98]) were significantly associated with PTSD. Those with a toxicology positive screen were 80% less likely to remaine in methadone maintenance at 1 year (OR [95% CI]; 0.20 [0.07–0.52]). PTSD diagnosis was not significantly associated with treatment retention at 1 year (OR [95% CI]; 0.61 [0.23–1.64]). Conclusions and Scientific Significance: Future studies are needed to determine if treatment of PTSD that is integrated into methadone maintenance programs may impact continued substance abuse use and thereby improve retention in care. (Am J Addict 2012;21:524–530)     

The Genetic Architecture of Chemosensory Cues Involved in Species Recognition: A Behavioral Approach in the House Mouse

The genetics of chemical signals is poorly understood. We addressed this issue in two subspecies of mice, Mus musculus musculus and M. m. domesticus, comparing their odor phenotypes with that of their hybrids. Earlier studies indicated that these subspecies could be discriminated on the basis of their urinary odor. We assessed male odor phenotypes from perception of musculus mice acting as olfactometers. Our results point to a complex genetic determinism. Reciprocal F1 hybrids produced a distinct odor phenotype, with shared characteristics distinguishing them from their parents, and stronger similarity to domesticus than to musculus. These results are consistent with implications of genes with partial dominance and a parent of origin effect. Further, similarities between reciprocal F2 allowed us to reject a direct role of the Y-chromosome in shaping the odor phenotype. However we show that the X-chromosome could be involved in explaining domesticus phenotype, while epistasis between genes on the sex chromosomes and the autosomes might influence musculus phenotype.