Search PubMed⌕ Search

Biomedical subjects

S L Hansen

Publications and source records attributed to S L Hansen.

At least 55 records · Page 3Linked to original sources
PubMed1984

Variation in the abilities of automated, commercial, and reference methods to detect methicillin-resistant (heteroresistant) Staphylococcus aureus.

The abilities of commercial MIC, automated, and reference methods for in vitro detection of methicillin-resistant Staphylococcus aureus were determined on 49 strains from eight hospitals. Micro-Media, MicroScan, Sensititre, Sceptor, API Uniscept KB, Abbott MS-2, Vitek AMS, Autobac MTS, NCCLS disk diffusion, and broth microdilution antimicrobial susceptibility testing procedures were evaluated. All testing was performed by using manufacturers' or reference procedures, and results were determined at no later than 24 h of incubation at 35 degrees C. With NCCLS disk diffusion, all strains were resistant to oxacillin (1 microgram), 47 (96%) were resistant to methicillin (4 micrograms), and 48 (98%) were resistant to nafcillin (1 microgram). The percentages of strains resistant to methicillin (greater than 8 micrograms/ml) were 98% with API Uniscept KB, 86% with Sceptor, MicroScan, and Autobac MTS, 84% with Sensititre, 71% with Micro-Media, and 70% with NCCLS MIC. Abbott MS-2 detected 86% of strains resistant to methicillin (greater than 5 micrograms/ml). With oxacillin (greater than 2 micrograms/ml), 90% were detected with Vitek AMS and 70% were detected with NCCLS MIC. With nafcillin (greater than 2 micrograms), 82% were resistant with Micro-Media, 57% were resistant by NCCLS MIC, and 50% (three of six) were resistant by MicroScan. Two strains from one hospital and one strain from another gave susceptible results with all automated and commercial methods. All strains from three centers were detected by all methods. Variability also occurred among the systems with cephalothin, clindamycin, gentamicin, chloramphenicol, and trimethoprim sulfamethoxazole.

Methicillin↗
PubMed1983

Resin-process methods for improved isolation of organisms from blood and other body fluids.

Two resin-based processes and conventional culturing methods were compared in isolating organisms from blood specimens of patients given antimicrobial agents. Of 20 patients whose specimens were found to contain clinically relevant organisms, one or both of the resin-process methods isolated organisms in eight after conventional culturing was unsuccessful. Conventional cultures were successful in five cases in which the resin-process methods did not work, and both resin-process and conventional culturing were successful in seven cases. In eight cases in which other body fluids were cultured, only a resin-process method was successful in four, although they are intended for use only with blood specimens. Data indicate that resin-process methods should be used along with conventional culturing methods when patients have already been given an antimicrobial. A review of the literature shows that the devices improve the recovery of organisms but does not establish that detection time is decreased.

Bacteria↗
PubMed1983

Concurrent comparability of automated systems and commercially prepared microdilution trays for susceptibility testing.

Susceptibility test results from 100 clinical isolates, using the AMS, MS-2, Autobac MTS, Micro-Media system, and Sensititre, were compared with results from the proposed National Committee for Clinical Laboratory Standards reference microdilution method for minimum inhibitory concentrations and with Bauer-Kirby results. Isolates were tested concurrently by each method on consecutive days to obtain duplicate results. The data were computer analyzed, using National Committee for Clinical Laboratory Standards guidelines for break point interpretation. Analysis was centered on drug-organism combinations and not on overall percent correlation. Data were analyzed for comparability to the reference methods and for reproducibility within each system. Commercial system results were very reproducible. Results from 4- to 8-h tests (AMS, MS-2, MTS) gave more very major discrepancies when compared with either reference method than did results from 15- to 18-h systems (Micro-Media, Sensititre).

Anti-Bacterial Agents↗
PubMed1983

Enhanced detection of polymicrobic bacteremia by repeat subculture of previously positive blood cultures.

Blood subcultures repeated 3 days after the cultures were first identified as positives increased our detection of polymicrobic bacteremia in 9.1 to 27% of clinically significant patient episodes. Reincubation and repeated subculture of previously positive blood cultures had a direct impact on the therapeutic management of patients with polymicrobic bacteremia.

Bacteriological Techniques↗
PubMed1981

Functionally deficient differentiation of HL-60 promyelocytic leukemia cells induced by phorbol myristate acetate.

The human promyelocytic leukemia cell line HL-60 undergoes terminal myeloid differentiation in vitro in response to a wide variety of chemicals. The tumor promoter phorbol myristate acetate induces these cells to develop macrophage-like morphology, adherence, and enzymatic characteristics. The present study confirms those observations and further documents the induction, by 16 nM phorbol myristate acetate, of 5'-nucleotidase activity, another human macrophage marker enzyme. However, more importantly, functional studies show that phorbol myristate acetate-induced HL-60 cells fail to increase above base line uninduced levels of hexose monophosphate shunt activity, superoxide generation, nitroblue tetrazolium reduction, bacterial ingestion, or complement secretion. These cells therefore possess some macrophage-like properties but do not meet several important functional criteria of macrophage identity.

Cell Differentiation↗
PubMed1980

A clinical evaluation of a card agglutination test for rheumatoid factor.

The Macro-Vue Card Test for Rheumatoid Factor (Hynson, Westcott, and Dunning) is a new commercially available card agglutination test designed for qualitative and quantitative procedures. Coded sera from 195 patients, six known positive sera, and two positive serum pools were tested using four commercial kits. The commercial kits evaluated included latex (Hyland RA Test, Behring-Rapi/tex RF Test), sheep erythrocytes (Wampole, Rheumaton), and charcoal (HWD-Macro-Vue RF Card Test) as carrier particles. Using the prescribed quantitative procedures, the percentages of positive and negative results for rheumatoid factor detected by each product were determined after the (serum) code was broken. The Macro-Vue test compares well with the Behring and Hyland latex dilution systems, and appears to detect more positive sera than the Wampole test. Titers obtained using the Macro-Vue test were more reproducible day to day with known positive sera than were titers obtained using any of the other kits.

Arthritis, Rheumatoid↗
PubMed1980

Variation in susceptibility patterns of species within the Bacteroides fragilis group.

Minimal inhibitory concentrations of eight antibiotics were determined for 159 clinical isolates of members of the Bacteroides fragilis group using the National Committee for Clinical Laboratory Standards proposed agar dilution reference method. Isolates were identified by standard techniques with deoxyribonucleic acid homolog confirmation. These closely related species demonstrated differences in susceptibility to commonly used drugs.

Anti-Bacterial Agents↗
PubMed1979

Comparison of three transport systems for recovery of aerobes and anaerobes from wounds.

A clinical evaluation of three commercially available transport systems (Anaerobic Specimen Collector, Becton-Dickenson; Anaswab, Scott Laboratories; and Trans-Cul, Wampole) was done, using as subjects 75 patients suspected of having infections. Holding times were purposely varied and ranged from 30 min to 48 hours. Totals of 22 aerobic species and 15 anaerobic species were isolated. There was essentially no difference among the three systems in the recoveries of aerobic or anaerobic organisms. Discrepancies appeared to be related to the order of collection and amount of clinical material available for culture. Time delay from collection to plating did not affect the recovery of aerobes or anaerobes. The three systems performed equally in the recovery of clinically significant pathogens from purulent clinical material.

Bacteria↗
PubMed1978

A reliable test for differentiation and presumptive identification of certain clinically significant anaerobes.

A modification of the slide catalase test was evaluated to determine its reliability for the presumptive identification of certain anaerobic gram-negative and gram-positive organisms isolated from clinical specimens. A total of 650 fresh isolates was evaluated. Growth from a trypticase blood agar plate or Schaedler's agar with laked blood was transferred to a slide and a drop of 15% H2O2 with Tween 80 added. Veillonella alcalescens, Proprionibacterium species, Peptococcus species, and Bacteroides fragilis, B. thetaiotaomicron, B. distasonis, B. ovatus, and B. vulgatus were positive by this method. Comparative slide and tube catalase tests were performed with the above-mentioned bacteroides species by growing each isolate on trypticase soy agar, Brucella agar, brain-heart infusion agar, each with and without added hemin, and on Schaedler's agar. Four solutions of H2O2 were used, 3 and 15%, and 3 and 15% with Tween 80. The addition of Tween 80 to H2O2 increased the sensitivity of the reaction with both slide and tube methods. The 15% H2O2 with Tween 80 consistently gave the most rapid and persistent positive reaction. A slide catalase test in combination with a Gram stain should be performed on each anaerobic isolate; this would significantly decrease the time required for presumptive identification of many anaerobic organisms.

Bacteria↗
PubMed1976

Comparison of API and Minitek to Center for Disease Control methods for the biochemical characterization of anaerobes.

Two commercially available micromethod multitest systems (API, Analytab Products, Inc., Minitek-Bioquest) were compared with conventional tests suggested by the Center for Disease Control for the identification of anaerobes. Anaerobiosis for the microsystems was achieved using GasPak system (BBL), A total of 175 anaerobes, including 158 clinical isolates and 17 reference strains, were used. Gram morphology, gas-liquid chromatography data, and biochemical reactions from the Center for Disease Control and Virginia Polytechnic Institute anaerobic manuals were used to identify the organisms. The Minitek system included a new anaerobe inoculum broth and two new disks, dextrose without nitrate and nitrate reductase disks. The percentage of correlation of 12 biochemicals using Minitek and 11 biochemicals using the API were compared with the Center for Disease Control reactions. The percentage of correlation of both positive and negative reactions with the API anaerobic strip ranged from 70.8 to 99.4% and with the Minitek from 97.1 to 100%. The microsystems were also evaluated as to the ease of use, adaptabilty to a clinical laboratory, time, and cost.

Anaerobiosis↗