Shortened Time to Identify Staphylococcus Species from Blood Cultures and Methicillin Resistance Testing Using CHROMAgar

The ability to rapidly differentiate coagulase-negative staphylococcus (CoNS) from Staphylococcus aureus and to determine methicillin resistance is important as it affects the decision to treat empiric antibiotic selection. The objective of this study was to evaluate CHROMagar S. aureus and CHROMagar MRSA (Becton Dickinson) for rapid identification of Staphylococcus spp. directly from blood cultures. Consecutive blood culture bottles (BacT Alert 3D SA and SN, bioMérieux) growing gram-positive cocci in clusters were evaluated. An aliquot was plated onto CHROMagar MRSA (C-MRSA) and CHROMagar S. aureus (C-SA) plates, which were read at 12 to 16 hours. C-SA correctly identified 147/147 S. aureus (100% sensitivity); 2 CoNS were misidentified as S. aureus (98% specificity). C-MRSA correctly identified 74/77 MRSA (96% sensitivity). None of the MSSA isolates grew on C-MRSA (100% specificity). In conclusion, CHROMagar is a rapid and sensitive method to distinguish MRSA, MSSA, and coagulase-negative Staphylococcus and may decrease time of reporting positive results

Adsorption of organics on MSC5A in supercritical CO 2: chromatographic measurements & stop & go simulation

Chromatographic measurements were made for the adsorption of benzene, toluene and m-xylene on molecular sieving carbon (MSC) in a supercritical fluid CO2 mixed with organics. A supercritical chromatograph packed with MSC was used to detect pulse responses of the organics. Adsorption equilibria and adsorption dynamic parameters for organics were obtained by moment analysis of the response peaks. Dependences of adsorption equilibrium constants, K*, and micropore diffusivity, D, on the amount adsorbed were examined. The dependencies of adsorption equilibrium constants, K*, and micropore diffusivities, D, for benzene, toluene and m-xylene, on the molarity of benzene over a range of temperature and pressure were obtained. Experimental results were simulated using the “Stop & Go” method as well as by molecular simulation

Staphylococcus aureus bacteriuria as a prognosticator for outcome of Staphylococcus aureus bacteremia: a case-control study

<p>Abstract</p> <p>Background</p> <p>When <it>Staphylococcus aureus </it>is isolated in urine, it is thought to usually represent hematogenous spread. Because such spread might have special clinical significance, we evaluated predictors and outcomes of <it>S. aureus </it>bacteriuria among patients with <it>S. aureus </it>bacteremia.</p> <p>Methods</p> <p>A case-control study was performed at John H. Stroger Jr. Hospital of Cook County among adult inpatients during January 2002-December 2006. Cases and controls had positive and negative urine cultures, respectively, for <it>S. aureus</it>, within 72 hours of positive blood culture for <it>S. aureus</it>. Controls were sampled randomly in a 1:4 ratio. Univariate and multivariable logistic regression analyses were done.</p> <p>Results</p> <p>Overall, 59% of patients were African-American, 12% died, 56% of infections had community-onset infections, and 58% were infected with methicillin-susceptible <it>S. aureus </it>(MSSA). Among 61 cases and 247 controls, predictors of <it>S. aureus </it>bacteriuria on multivariate analysis were urological surgery (OR = 3.4, p = 0.06) and genitourinary infection (OR = 9.2, p = 0.002). Among patients who died, there were significantly more patients with bacteriuria than among patients who survived (39% vs. 17%; p = 0.002). In multiple Cox regression analysis, death risks in bacteremic patients were bacteriuria (hazard ratio 2.9, CI 1.4-5.9, p = 0.004), bladder catheter use (2.0, 1.0-4.0, p = 0.06), and Charlson score (1.1, 1.1-1.3, p = 0.02). Neither length of stay nor methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) infection was a predictor of <it>S. aureus </it>bacteriuria or death.</p> <p>Conclusions</p> <p>Among patients with <it>S. aureus </it>bacteremia, those with <it>S. aureus </it>bacteriuria had 3-fold higher mortality than those without bacteriuria, even after adjustment for comorbidities. Bacteriuria may identify patients with more severe bacteremia, who are at risk of worse outcomes.</p

Carbapenem Susceptibility Patterns for Clinical Isolates of Mycobacterium abscessus Determined by the Etest Method▿

Mycobacterium abscessus is resistant to multiple antibiotics, creating treatment challenges. Carbapenems are tested to increase therapeutic alternatives. We performed in vitro susceptibility testing by Etest of four carbapenems for M. abscessus isolates. Imipenem demonstrated the most in vitro activity, and testing of other carbapenems provided no additional value

Adsorption of organics on MSC5A in supercritical CO2, chromatographic measurements & stop & go simulation

Chromatographic measurements were made for the adsorption of benzene, toluene and m-xylene on molecular sieving carbon (MSC) in a supercritical fluid CO2 mixed with organics. A supercritical chromatograph packed with MSC was used to detect pulse responses of the organics. Adsorption equilibria and adsorption dynamic parameters for organics were obtained by moment analysis of the response peaks. Dependences of adsorption equilibrium constants, K*, and micropore diffusivity, D, on the amount adsorbed were examined. The dependencies of adsorption equilibrium constants, K*, and micropore diffusivities, D, for benzene, toluene and m-xylene, on the molarity of benzene over a range of temperature and pressure were obtained. Experimental results were simulated using the “Stop & Go” method as well as by molecular simulation

Adsorption of organics on MSC5A in supercritical CO 2: chromatographic measurements & stop & go simulation

Chromatographic measurements were made for the adsorption of benzene, toluene and m-xylene on molecular sieving carbon (MSC) in a supercritical fluid CO2 mixed with organics. A supercritical chromatograph packed with MSC was used to detect pulse responses of the organics. Adsorption equilibria and adsorption dynamic parameters for organics were obtained by moment analysis of the response peaks. Dependences of adsorption equilibrium constants, K*, and micropore diffusivity, D, on the amount adsorbed were examined. The dependencies of adsorption equilibrium constants, K*, and micropore diffusivities, D, for benzene, toluene and m-xylene, on the molarity of benzene over a range of temperature and pressure were obtained. Experimental results were simulated using the “Stop & Go” method as well as by molecular simulation

Adsorption of organics on MSC5A in supercritical CO 2: chromatographic measurements & stop & go simulation

Chromatographic measurements were made for the adsorption of benzene, toluene and m-xylene on molecular sieving carbon (MSC) in a supercritical fluid CO2 mixed with organics. A supercritical chromatograph packed with MSC was used to detect pulse responses of the organics. Adsorption equilibria and adsorption dynamic parameters for organics were obtained by moment analysis of the response peaks. Dependences of adsorption equilibrium constants, K*, and micropore diffusivity, D, on the amount adsorbed were examined. The dependencies of adsorption equilibrium constants, K*, and micropore diffusivities, D, for benzene, toluene and m-xylene, on the molarity of benzene over a range of temperature and pressure were obtained. Experimental results were simulated using the “Stop & Go” method as well as by molecular simulation