Interpretive criteria for testing susceptibility of staphylococci to mupirocin

To determine appropriate mupirocin susceptibility testing interpretive criteria, 177 staphylococci were tested by agar dilution, disk diffusion, and E test. E test was found to be a reliable method for determining susceptibility of staphylococci to mupirocin. The agar dilution and disk diffusion results were plotted on a scattergram, and error rates were calculated. No errors were found with susceptibility breakpoints of > or = 4 microg/ml (MIC) and > or = 14 mm (zone diameter).     

Identification of mecA-related oxacillin resistance in staphylococci by the E test and the broth microdilution method

A set of 165 strains of different staphylococcal species, 67 Staphylococcus aureus, 71 novobiocin-sensitive coagulase-negative staphylococci (CNS) and 27 novobiocin-resistant CNS was used. The oxacillin and methicillin MICs were recorded after 24 and 42 h of incubation at 35 degrees C and at 30 degrees C. Significantly higher MICs were recorded at 30 degrees C compared with 35 degrees C. While a poor discrimination between mecA-positive and mecA-negative strains was obtained with methicillin, the oxacillin MICs enabled identification of resistant strains under certain conditions. The distribution of MICs differed between the three groups of species. Separation of uninduced mecA-positive (> or = 4.0 mg oxacillin/L) and mecA-negative (< or = 2.0 mg oxacillin/L) strains of S. aureus was only achieved with the E test and after 42 h of incubation. Oxacillin-induction yielded higher MICs for mecA-positive strains of S. aureus, and a separation from mecA-negative strains was achieved with the E test after 24 h and with the broth microdilution method after 42 h. Separation of mecA-positive and mecA-negative strains of novobiocin-sensitive CNS required agar supplemented with 5% blood, incubation of MIC trays and E test for 42 h, and species-specific oxacillin MIC breakpoints (S < or = 0.5 mg/L and R > or = 1.0 mg/L). The mecA-positive and mecA-negative strains of novobiocin-resistant CNS were clearly separated after 24 h of incubation by either method.     

In-vitro activity of three fluoroquinolones, cefotaxime and clindamycin against staphylococci

The in-vitro activity of three fluoroquinolones (ciprofloxacin, ofloxacin, temafloxacin) against 200 well-defined clinical isolates of staphylococci was investigated. The in-vitro activity of the fluoroquinolones tested was equal, with a strong indication of cross resistance. A clear distribution over two populations of different quinolone susceptibility--"naturally susceptible" and "naturally resistant" strains--could be found in penicillin-resistant, methicillin-susceptible Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus haemolyticus.     

Evaluation of mannitol salt agar for detection of oxacillin resistance in Staphylococcus aureus by disk diffusion and agar screening

Mannitol salt agar was evaluated for detection of oxacillin resistance in 136 Staphylococcus aureus isolates. All mecA-positive isolates (n = 54) were correctly categorized as oxacillin resistant by the disk diffusion test (1-microgram disk; zone diameter, < 16 mm); the specificity was 97.6%. Agar screening (2 micrograms of oxacillin per ml) revealed a sensitivity of 98.1% and a specificity of 95.1%.     

Phenotypic and functional characterization of mice that lack the type I receptor for IL-1

IL-1 alpha and IL-1 beta bind to receptors termed the type I and type II IL-1 receptors. The type I IL-1 receptor is responsible for specific signaling, while the type II IL-1 receptor functions as a nonsignaling decoy receptor. To determine the effect of a defect in IL-1-mediated signaling, mice have been produced with a genetically disrupted type I IL-1 receptor gene. Mice lacking type I IL-1 receptors are of normal vigor and exhibit no overt phenotype. B cells from type I IL-1R-/- mice activated in vitro with anti-IgM do not proliferate in response to IL-1, but do so in response to IL-4. Injection of murine IL-1 alpha does not induce detectable serum IL-6 levels in type I IL-1R-/- mice, but equivalent levels are produced in response to LPS. Type I IL-1R-/- mice have normal serum Ig levels and generate equivalent primary and secondary Ab responses as wild-type mice. In response to LPS, acute phase protein mRNA induction are equivalent in type I IL-1R-/- and wild-type mice. Type I IL-1R-/- mice do not differ from control mice in susceptibility to either a lethal challenge with D-galactosamine plus LPS or high dose LPS. Interestingly, ICE-/-/type I IL-1R-/- double mutant mice are resistant to high dose LPS. Type I IL-1R-/- mice backcrossed to the C57BL/6 background were as equally resistant as wild-type mice to Listeria monocytogenes.     

Comparison of agar dilution, broth microdilution, E-test, disk diffusion, and automated Vitek methods for testing susceptibilities of Enterococcus spp. to vancomycin

An evaluation was undertaken to determine the optimal method for testing the susceptibilities of 100 clinical isolates and two reference strains of Enterococcus spp. to vancomycin in vitro. Six testing methods were studied by using the following media and incubation times: agar screen with the Synergy Quad Plate (Remel, Lenexa, Kans.), an in-house-prepared brain heart infusion (BHI) agar plate, and an in-house-prepared Mueller-Hinton (MH) agar plate, all incubated for 24 or 48 h; broth microdilution (Sensititre Just One Strip; AccuMed International, Inc., West Lake, Ohio) with BHI or cation-adjusted MH broth incubated for 24 or 48 h; agar dilution with BHI or MH agar incubated for 24 or 48 h; epsilometer test (E test; AB BioDisk, Solna, Sweden) with BHI or MH agar incubated for 24 or 48 h; disk diffusion with BHI or MH agar incubated for 24 or 48 h; and the automated Vitek method with the gram-positive susceptibility Staphylococcus aureus card and R02.03 software (bioMerieux, Inc., Hazelwood, Mo.). Growth failures occurred with MH media (n = 6) but not with BHI media. One growth failure occurred with the Vitek method. Results for each testing method for each Enterococcus strain were interpreted as susceptible, intermediate, or resistant according to current National Committee for Clinical Laboratory Standards (NCCLS) criteria and compared to the vancomycin resistance genotype (i.e., vanA, vanB, vanC-1, or vanC-2/3). For all methods, extension of the incubation time from 24 h to 48 h either produced no difference in the results or gave poorer results. The following methods produced no very major or major interpretive errors: broth microdilution with BHI media incubated for 24 h, agar dilution with BHI media incubated for 24 or 48 h, and E test with BHI media incubated for 24 or 48 h. Unacceptable frequencies of very major errors (> 1%) occurred with all methods for which MH media were used. Minor interpretive errors were frequent with all methods. These minor interpretive errors also occurred most frequently with Enterococcus strains with vanC genes, which encoded low-level vancomycin resistance (MIC < or = 8 microg/ml), as opposed to Enterococcus strains which possessed vanA or vanB genes, which encoded higher-level vancomycin resistance (MIC > or = 64 microg/ml). Modification of NCCLS breakpoints, especially for motile Enterococcus spp. (E. casseliflavus, E. flavescens, and E. gallinarum), may resolve this problem; however, in the current study, one E. faecalis strain and one E. faecium strain carried only the vanC gene. The agar screen method may also require reformulation. The current agar screen plate contains 6 microg of vancomycin per ml, which may not detect all low-level resistance associated with vanC genotypes. Nevertheless, the clinical significance of this low-level vancomycin resistance remains unknown.     

Comparison of agar dilution, disk diffusion, MicroScan, and Vitek antimicrobial susceptibility testing methods to broth microdilution for detection of fluoroquinolone-resistant isolates of the family Enterobacteriaceae

Fluoroquinolone resistance appears to be increasing in many species of bacteria, particularly in those causing nosocomial infections. However, the accuracy of some antimicrobial susceptibility testing methods for detecting fluoroquinolone resistance remains uncertain. Therefore, we compared the accuracy of the results of agar dilution, disk diffusion, MicroScan Walk Away Neg Combo 15 conventional panels, and Vitek GNS-F7 cards to the accuracy of the results of the broth microdilution reference method for detection of ciprofloxacin and ofloxacin resistance in 195 clinical isolates of the family Enterobacteriaceae collected from six U.S. hospitals for a national surveillance project (Project ICARE [Intensive Care Antimicrobial Resistance Epidemiology]). For ciprofloxacin, very major error rates were 0% (disk diffusion and MicroScan), 0.9% (agar dilution), and 2.7% (Vitek), while major error rates ranged from 0% (agar dilution) to 3.7% (MicroScan and Vitek). Minor error rates ranged from 12.3% (agar dilution) to 20.5% (MicroScan). For ofloxacin, no very major errors were observed, and major errors were noted only with MicroScan (3.7% major error rate). Minor error rates ranged from 8.2% (agar dilution) to 18.5% (Vitek). Minor errors for all methods were substantially reduced when results with MICs within +/-1 dilution of the broth microdilution reference MIC were excluded from analysis. However, the high number of minor errors by all test systems remains a concern.     

A deficit for arithmetical procedures: lack of knowledge or lack of monitoring?

A patient is described with a specific deficit for arithmetical procedures. Unlike in previously described cases, where the observed problems could be attributed to the systematic application of disturbed algorithms, this patient's difficulty seems to stem from an inability to monitor the sequence of operations that calculation procedures specify. Criteria are provided for distinguishing impairments in written calculation due to the application of defective knowledge of the procedures from those determined by lack of monitoring. The role of monitoring and control processes in different calculation components is also discussed.     

拉伸试验中测量不确定度的评定

根据实验室认可要求,对拉伸试验测量不确定度的评定过程和基本方法及试样形状、尺寸、试验人员、尺寸测量器具、试验机的影响因素做了简单的讨论.     

Evaluation of recovery filters for use in bacterial retention testing of sterilizing-grade filters

Membrane filters with pore-size ratings of 0.22 microns and 0.45 microns were tested for their ability to recover Pseudomonas diminuta ATCC 19146 (P. diminuta), the organism typically used in bacterial retention testing of sterilizing-grade membrane filters. For each of the two pore-size ratings, filters of two membrane filter polymer materials, hydrophilic PVDF (Millipore Durapore) and mixed esters of cellulose, were tested, resulting in an evaluation of four potential recovery filters. The 0.45 microns mixed esters of cellulose filter is the currently accepted membrane for this purpose. The data show no difference in the ability of the four filters to recover freshly cultured P. diminuta. Moreover, the membrane-filter method was shown to provide a very high bacterial-recovery efficiency, equivalent to that of the spread-plate method. Thus, 0.22 micron filters, despite their ability to retain higher levels of bacteria, proved not to have an advantage over 0.45 micron membranes in terms of bacterial recovery. This result, combined with (1) the knowledge that more open membranes have been shown experimentally to more efficiently recover stressed organisms; (2) the potential to produce stressed cells in an actual bacterial retention test; and (3) the long history of the successful use of 0.45 microns mixed esters of cellulose for bacterial recovery, support the continued use of the 0.45 micron filter in this application.     

21st birthday celebratory drinking: Evaluation of a personalized normative feedback card intervention.

This research was designed to evaluate a personalized normative feedback birthday card intervention aimed at reducing normative perceptions, alcohol consumption, and negative consequences associated with 21st birthday celebrations among college students (N=281; 59.15% women). Students were randomly assigned to receive or not receive a birthday card about 1 week prior to their 21st birthday. Approximately 1 week following their birthday, students were asked to complete a brief survey concerning their birthday celebration activities. Findings indicated that the birthday card intervention was not successful at reducing drinking or consequences; however, the card did reduce normative misperceptions. Additional findings indicated that many students experienced negative consequences, such as passing out or driving after consuming alcohol. Combined, these findings suggest that prevention is needed for drinking associated with turning 21. However, prevention efforts should consist of more than a birthday card. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of a new Army visual testing instrument.

A new device (Instrument B—an optical device to simulate the 20-foot distance of wall alleys) for testing photopic visual acuity was evaluated by comparison of test results with those obtained from the Standard Wall Chart Visual Acuity Examination (WC). Instrument B scores and WC scores correlated in the .90's, and test-retest reliabilities were also in the .90's. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessment of oxacillin salt agar for detection of MRSA identified by presence of the mecA gene

Progressive growth of immunogenic murine tumors elicits a tumor-specific but functionally deficient T-cell immune response in the draining lymph nodes. These T cells, referred to as "pre-effector" cells could be induced in vitro to differentiate into mature immune effector cells, capable of mediating the regression of established metastases. Initially, tumor cells were used to stimulate the in vitro maturation of pre-effector cells. Alternatively, we found that pre-effector cells could be activated by sequential stimulation with anti-CD3 and interleukin-2 in the absence of tumor cells. In adoptive immunotherapy, these activated cells mediated therapeutic effects that were exquisitely specific to the tumor that triggered the pre-effector cell response in vivo. Since the anti-CD3 interaction with T cells is polyclonal, the activated lymph node cell population must also contain a significant number of T cells that do not have tumor specificity. In an attempt to selectively activate tumor-sensitized pre-effector cells, we recently utilized superantigenic bacterial toxins as T-cell stimuli for effector cell generation. Superantigens combine with major histocompatibility class II molecules to form the ligands that stimulate T cells bearing distinct T-cell receptor V beta elements. Lymph node cells draining the MCA 205 sarcoma stimulated with staphylococcal enterotoxins A (SEA), B (SEB), or C2 (SEC2) resulted in selective expansions of V beta 3 and 11, V beta 3 and 8, or V beta 8.2 T cells, respectively. Adoptive immunotherapy experiments revealed that SEB- and SEC2-, but not SEA- stimulated cells, mediated tumor-specific eradication of pulmonary metastases.(ABSTRACT TRUNCATED AT 250 WORDS)     

Chromosomal determinants for exfoliative toxin production in two strains of staphylococci

Strain TG is a plasmidless exfoliative toxin (ET) producer. Strain ER201 contains a plasmid, whose loss had no apparent effect on ET production. The plasmid of ER201 was almost identical in size to the plasmid from strain UT0007, which carries an ET determinant.     

Evaluation of effective treatment drugs against Acanthamoeba cyst

Cysts of 2 isolates of Acanthamoeba from the cornea of 2 patients with confirmed Acanthamoeba keratitis were tested in vitro for sensitivity to antimycotic agents such as fluconazole, miconazole, amphotericin-B, pimaricin, antiprotozoal agents such as pentamidine isetionate and antiseptics which could be use in the ophthamological region. Pimaricin was the most successful cysticidal agent against the two strains. Sensitivity to pentamidine isetionate showed variation. Fluconazole, miconazole and amphotericin-B were resistant against cysts with concentration of eye drops that have been used in the treatment of Acanthamoeba keratitis. It was supposed that 5% pimaricin eye drops could be use in the treatment of Acanthamoeba keratitis in addition to keratomycosis. Pentamidine isetionate which belong to the diamidine family, is not yet clear as to the side effects to corneal epithelium cell, but we believe that this drug could be expected as a new therapeutic agent for Acanthamoeba keratitis.     

Evaluation of drug formulations using LD50 testing in mice

The LD50 values were utilized to assess the relative rate of absorption of two very poorly soluble drugs. Formulations of these drugs were studied by micronization; addition of surfactant, alkaline or buffering agents, and/or bile salts; coprecipitation; melt or fusion techniques; or granulation with hydrophilic agents. Differences in toxicities were demonstrated from formulations compared to pure drugs by the LD50 method. This study shows that the LD50 is a practical, rapid method of achieving comparative evaluations of drug formulations.     

Z-0.8/25型乙炔压缩机正压保护系统的检测方法

Z-0.8/25型乙炔压缩机,是目前乙炔行业中应用最为广泛,性能较为可靠的压缩机,也是广东韶关钢铁集团有限公司华欣乙炔厂的主体设备.由于乙炔气是极其易燃易爆的气体,破坏力特强.因此在乙炔压缩机的进出气装置上,分别设置了正压