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Biomedical subjects

J V Bennett

Publications and source records attributed to J V Bennett.

At least 55 records · Page 3Linked to original sources
PubMed1974

Proposed standardized method for testing and interpreting susceptibility of Bacteroides fragilis to tetracycline.

One hundred twenty-four strains of Bacteroides fragilis were examined for susceptibility to tetracycline disks and by minimal inhibitory concentration (MIC) determinations. MIC values and zone sizes around 30-mug tetracycline disks were determined by using selected test conditions which included Mueller-Hinton agar supplemented with sheep blood, vitamin K, and hemin and an incubation temperature of 35 C in an atmosphere of 80% N(2), 10% H(2), and 10% CO(2). Strains were separated into two distinct populations by geometric mean MIC and dis tests. Of the 124 strains, 78 were resistant and 46 were susceptible. The resistant strains had geometric mean MIC's of 8 mug/ml or greater, whereas the geometric mean MIC's of sensitive strains were 5 mug/ml or less. The disk test proved to be more reproducible than the MIC test and completely separated the resistant and susceptible populations. An interpretive scheme for B. fragilis to tetracycline was statistically derived on the basis of the distribution of zone sizes of susceptible and resistant strains: resistant, 18 mm or less; indeterminant, 19 to 20 mm; and susceptible, 21 mm or greater. These zone sizes compared closely with the Kirby-Bauer criteria for aerobic bacteria.

Anti-Bacterial Agents↗
PubMed1971

Characteristics of antimicrobial resistance of Escherichia coli from animals: relationship to veterinary and management uses of antimicrobial agents.

Five-hundred fifty-five (555) isolates of Escherichia coli were obtained from fecal specimens of a representative number of animals from five farms in the United States. Antibiotic exposure of the selected herds was determined by an epidemiological survey of these farms. The incidence of multiple resistance in the E. coli isolates was higher in herds exposed to continuous feeding of antimicrobial agents (84.8%) than in a herd not receiving antimicrobials (15.7%). The most common resistance configuration observed was the triple pattern of dihydrostreptomycin (DS), sulfonamide (SU), and tetracycline (TE). The second most frequent pattern consisted of four resistances: ampicillin (AM), DS, SU, and TE. The frequency of transfer factors was much higher in multiply resistant organisms from the herds exposed to antimicrobial medicaments. The E. coli isolates were relatively efficient in fostering and transferring heterologous resistance factors. AM resistance factors occurred more frequently in herds which were exposed to feed levels of penicillin (27.9%) than in those that were not (6.4%).

Animal Diseases↗