The FDA review criteria for assessment of antimicrobial susceptibility devices--too much or not enough regulation?
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Clinical Trials as Topic↗
Biomedical subjects
K M Tomfohrde
Publications and source records attributed to K M Tomfohrde.
Rapid antimicrobial susceptibility testing of gram-negative bacilli using Baxter MicroScan rapid fluorogenic panels and autoSCAN-W/A.
The MicroScan Rapid Neg MIC/Combo panels and autoSCAN-W/A (Walk Away) system utilize automated fluorescence technology for rapid antimicrobial susceptibility testing of Gram-negative bacilli. In a three site clinical study eleven antimicrobial agents were evaluated by comparing results obtained with 741 clinical isolates, using rapid fluorogenic expanded dilution MIC panels and corresponding frozen microdilution reference panels determined visually. Results for 31%, 40%, 12% and 9% of the isolates were available within 3.5, 4.5, 5.5 and 7.0 hours respectively. Results for 7.3% were not available within that time period. For the seven drugs analyzed using a Minimum Inhibitory Concentration range of dilutions, overall agreement (+/- 1 dilution) was 94%, with 1.5% very major, 0.9% major and 2.5% minor errors. For the four drugs analyzed using a Breakpoint range of dilutions, overall agreement (+/- 1 dilution) was 97%, with two percent very major, and one percent major errors. The MicroScan Rapid Neg MIC system is an accurate and rapid method for same day determination of susceptibility of Gram-negative bacilli.
Anti-Bacterial Agents↗
Rapid antimicrobial susceptibility testing of gram-positive cocci using Baxter MicroScan rapid fluorogenic panels and autoSCAN-W/A.
The Microscan Rapid Pos MIC/Combo panels and autoSCAN-W/A (Walk Away) system utilize automated fluorescence technology for rapid antimicrobial susceptibility testing of staphylococci, streptococci, and Listeria. In a three site clinical study, panels containing 26 antimicrobial agents were evaluated by comparing results obtained with 605 clinically significant isolates, using rapid fluorogenic expanded dilution MIC panels and corresponding frozen microdilution reference panels. Results for 16%, 40%, 13%, 9%, 8%, 11% and 1% of the isolates were available within 3.5, 4.5, 5.5, 7.0, 8, 11 and 15 h respectively. Results for 2% were not available within that time period. Overall agreement (+/- 1 dilution) for the 14,609 efficacy comparisons was 96%, with 1% each for very major, major and minor errors. Interlaboratory reproducibility testing of 25 isolates in triplicate in each site, showed an overall essential agreement of 97%. The MicroScan Rapid Pos MIC System is an accurate, reproducible and rapid method for same-day determination of susceptibility of Gram-positive cocci.
Anti-Bacterial Agents↗
Influence of media on temperature-dependent motility test for Yersinia enterocolitica.
The influence of six widely used media on the motility of 100 isolates of Yersinia enterocolitica grown at 25 and 37 degrees C was investigated. Seven isolates were motile at 25 and 37 degrees C in all media, and the presence of flagellated cells was demonstrated by a flagellum stain. Six isolates were nonmotile at both temperatures in all media, and no flagella were observed. Identification schemes for Y. enterocolitica should reflect these possibilities.
Bacteriological Techniques↗
Incidence of "oxidase-variable" strains of Aeromonas hydrophila.
Certain strains of Aeromonas hydrophila are oxidase negative when grown on gram-negative selective and differential media. Of 100 strains of A. hydrophila examined, 8 were found to possess this characteristic. Information is provided on how to detect these common variants of A. hydrophila.
Aeromonas↗
Rapid identification of Neisseria gonorrhoeae and Neisseria meningitidis by using enzymatic profiles.
The enzymatic profiles of Neisseria gonorrhoeae, N. meningitidis, and related species were determined, using a total of 48 chromogenic substrates. Enzyme classes assayed for included glycosidases, aminopeptidases, phosphoamidases, proteases, lipases, esterases, and aryl sulfatase. A final test selection of 10 substrates, based upon their differential and reproducible characteristics, allowed the separation of N. gonorrhoeae and N. meningitidis from each other and from all species tested within 4 h after primary isolation on modified Thayer-Martin medium. The need for subculturing suspect colonies from modified Thayer-Martin medium to chocolate medium with a subsequent loss of 18 to 24 h of identification is eliminated.
Aminopeptidases↗
Evaluation of the Bactrol Disks, a set of quality control cultures.
A set of commercially available quality control cultures was evaluated. These cultures were found to be an acceptable alternate to lyophilized or continuously subcultured cultures for a quality control program.
Anti-Bacterial Agents↗
Evaluation of the pathotec Rapid I-D system for identification of Enterobacteriaceae.
The PathoTec Rapid I-D System for identifying Enterobacteriaceae was evaluated with 471 cultures. In 4,910 individual test comparisons, 95.5% of the results agreed, with results of only two test strips, those for esculin hydrolysis and urease production, agreeing with conventional tests in less than 94% of the trials. The PathoTec system exhibited 94.3% accuracy in identifying these cultures in a double-blind study with conventional media and procedures as the alternate system. Two newly developed test strips, for 0-nitrophenyl-beta-D-galactopyranoside and ornithine decarboxylase, were found to be highly reliable.
Classification↗
Auxotab--a device for identifying enteric bacteria.
A multitest system called the Auxotab that uses ten dehydrated reagents on a paper card has been evaluated with 417 known stock cultures of Enterobacteriaceae. In double-blind studies with the Auxotab, 87% of the strains tested were correctly identified. Results of this study indicate that there is a need for modification of the product in regard to ease of handling, time required for use, and accuracy of identification of enteric bacteria.
Bacteriological Techniques↗
Evaluation of the redesigned enterotube--a system for the identification of Enterobacteriaceae.
The redesigned Enterotube has been evaluated with 414 unknown Enterobacteriaceae cultures from the stock culture collection of the Center for Disease Control. When the Enterotube was used as recommended by the manufacturer, an average of 96.4% of these cultures were correctly identified. Only two groups (Salmonella and Edwardsiella) were identified with less than 90% accuracy (89.2 and 87.5%, respectively). The Enterotube now provides a convenient, rapid, and accurate test system for the identification of typically reacting enteric bacteria.
Bacteriological Techniques↗
Evaluation of the improved Auxotab 1 System for identifying Enterobacteriaceae.
The improved Auxotab Enteric 1 System is more accurate in identifying Enterobacteriaceae than is the original product, and results correlate better with those obtained with conventional tests.
Bacteriological Techniques↗
API system: a multitube micromethod for identification of Enterobacteriaceae.
The API system for identification of Enterobacteriaceae was evaluated with 366 cultures. Overall accuracy of identification was 96.4%; of the 13 cultures misidentified, 7 were atypical strains.
Bacteriological Techniques↗
R-B enteric differential system for identification of Enterobacteriaceae.
The R/B Enteric Differential System for identifying enteric bacteria has been evaluated with 451 "unknown" cultures from the stock culture collection of the Center for Disease Control. An average of 89.6% of these cultures were correctly identified by the R/B system, when used as recommended by the manufacturer but without the assistance of serology. This percentage ranged, however, from 47% for Klebsiella to 100% for Serratia and Providencia. Of 11 groups or genera of Enterobacteriaceae tested, only three (Enterobacter, Serratia, and Providencia) were identified with 95% or better accuracy. Four groups (Arizona, Citrobacter, Escherichia, and Salmonella) attained 90 to 95% accuracy of identification, and three groups (Edwardsiella, Proteus, and Shigella) scored between 85 and 90% accuracy. We recommend the R/B system as a screening device which is reasonably successful in grouping bacteria but not as a substitute for more exacting conventional procedures.
Bacteriological Techniques↗
Evaluation of the modified R-B system for identification of Enterobacteriaceae.
In comparison with conventional procedures, a modified R/B Enteric Differential System permitted more accurate identification of enteric bacteria than did the original R/B system.
Bacteriological Techniques↗