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Biomedical subjects

R C Tilton

Publications and source records attributed to R C Tilton.

At least 73 records · Page 4Linked to original sources
PubMed1978

Evaluation of an automated agar plate streaker.

An automated agar plate streaker was evaluated. The Autostreaker mechanizes the agar plate streaking process by providing storage for plates, labeling and streaking one or more plates for either isolation or quantitation, and stacking in one of several racks for subsequent incubation. Results showed the Autostreaker to produce agar plates with well-separated colonies and accurate colony counts. A total of 1,930 clinical specimens were processed either in parallel with manual methods or solely by the Autostreaker. Technologist acceptance of machine-streaked plates was outstanding.

Bacteriological Techniques↗
PubMed1978

Counterimmunoelectrophoresis in biology and medicine.

The review will initially focus on the historical development of counterimmunoelectrophoresis (CIE). A part of the manuscript will be devoted to methodological considerations of CIE as well as a discussion of the antisera used. The body of the review will detail each test procedure for which CIE is applicable and discuss unique elements of technique and limits of detection, as well as clinical interpretation of results. The final section will summarize potential applications of CIE in microbiology.

Antibodies↗
PubMed1977

Rapid method for determining the minimum inhibitory concentration of ampicillin for Haemophilus influenzae.

A rapid method for determining the minimal inhibition concentrations (MICs) of ampicillin using Haemophilus influenzae as the test organism is described. This semiautomated technique using the Autobac system was compared with the agar dilution MIC method. Fifty-seven isolates of both susceptible and resistant H. influenzae were tested. There was exact quantitative agreement with 65% of the isolates, and 91% of the isolates showed no more than a one-dilution-interval difference when MICs were determined by both methods. Total testing time was 3 to 4 h.

Ampicillin↗
PubMed1977

Evaluation of the performance parameters of a prediluted, quantitative antibiotic susceptibility test device.

A multiwelled plastic strip containing prediluted antibiotics was tested. Antibiotics available at the time of testing included ampicillin, penicillin, methicillin, erythromycin, clindamycin, tetracycline, and minocycline. The effects of inoculum size, inoculum volume, temperature, and time of incubation were determined. A limited clinical evaluation using laboratory strains of selected bacteria proved this product to be a rapid, economical, and reliable method for the determination of the minimal inhibitory concentration of antibiotics.

Anti-Bacterial Agents↗
PubMed1977

In-use evaluation of a prediluted quantitative antibiotic susceptibility test device.

An antibiotic susceptibility test (AST) device is described. Minimum inhibitory concentration results on 1,294 clinical isolates with seven antibiotics were rapid, reliable, and reproducible. Agreement with the disk diffusion test was 90%. Interlaboratory agreement for the AST was 94%. The AST provides minimum inhibitory concentration capability without the necessity of prior weighing and dilution of antibiotics.

Anti-Bacterial Agents↗
PubMed1976

The microdilution antibiotic susceptibility test. Bacteroides fragilis.

A micro broth-dilution method was developed for the antibiotic susceptibility testing of Bacteroides frgilis. Eighty strains of B. fragilis were tested against six antibiotics using the agar dilution test as the reference method. The microdilution test yielded results in 24 hours, and agreement with the reference test was satisfactory. Certain subspecies-specific patterns of antibiotic susceptibility were observed. However, larger numbers of subspecies should be evaluated before subspeciation of B. fragilis can be used as a reliable predictor of antibiotic susceptibility.

Ampicillin↗
PubMed1976

Synergism of cefazolin-gentamicin against enterococci.

A miniaturized technique for detecting antibiotic synergy by using microliter volumes was perfected. With this microtiter serial dilution method, the effect of the previously untried combination of cefazolin and gentamicin on 10 strains of enterococci was evaluated. At clinically achievable concentrations, the combination of cefazolin and gentamicin was found to be synergistic against all 10 strains when the data were plotted in the form of an isobologram. These results were compared with the conventional method of detecting synergy in vitro, namely, the determination of the rate of killing of the microorganisms with the antibiotics, singly and in combination. Similar results were also observed. These findings indicate that the microtiter serial dilution technique is a useful method for the routine determination of drug synergy. Moreover, in a patient with penicillin hypersensitivity and enterococcal infection, the combination of cefazolin and gentamicin should be considered for possible therapy.

Cefazolin↗
PubMed1975

Activity of minocycline against Acinetobacter calcoaceticus var. anitratus (syn. Herellea vaginicola) and Serratia marcescens.

The activity of minocycline and tetracycline against 23 isolates of Acinetobacter calcoaceticus var. anitratus (syn. Herellea vaginicola) and 178 strains of Serratia marcescens was determined by disk and microdilution methods. The results indicate that minocycline is highly active against this species of Acinetobacter, all but one strain being inhibited by 0.007 mug of the antibiotic per ml. Tetracycline was also active, though to a lesser degree, against A. calcoaceticus. Of the 178 strains of S. marcescens tested, only seven (3.9%) had a minimum inhibitory concentration of 2 mug or less of minocycline per ml. Tetracycline was less active than minocycline against S. marcescens; with 2 mug of tetracycline per ml, only 2 of 152 (1.3%) strains were inhibited. At concentrations of 8 and 16 mug of minocycline per ml, which can be achieved in the urine with the usual doses, 44.9 and 63.5% of S. marcescens strains were inhibited, which implies its possible usefulness for the therapy of urinary tract infection due to this organism.

Acinetobacter↗
PubMed1975

Detection of Candida vaginitis by a dipstick method.

A media impregnated polystyrene strip was tested for its ability to detect Candida in vaginal secretions. Of 230 patients with vaginitis, 20 were positive for Candida when the gram stain, routine culture, and Microstix-Candida (M-C) were used. Routine culture alone detected 17 cases, while the M-C alone detected 14 cases. Although this test system should not be used as a primary laboratory diagnostic tool, its use as an office or clinic screening test for vaginal candidiasis is recommended.

Candidiasis, Vulvovaginal↗
PubMed1973

Microdilution antibiotic susceptibility test: examination of certain variables.

A semiautomated microdilution susceptibility test is described. The effect of certain parameters such as inoculum size, growth media, incubation conditions, and inoculum dispensing systems was studied. Both medium type and inoculum size caused significant variations in the minimum inhibitory concentrations (MIC) of certain antibiotic-organism combinations. No effect on MIC was observed as a function of incubator type. Efforts to read a reproducible MIC value in less than 12 h failed. A commercially available wire pronged inoculator was determined to be inaccurate and unsafe. Disposable dropper pipettes proved to be economical, accurate, and precise. Although a standard method for microdilution antibiotic susceptibility testing is not proposed, data are presented which show that future attempts at standardized procedures are mandatory if inter- and intralaboratory reliability is desired.

Adenine↗