title: Permeability to beta-lactams in Bacteroides fragilis.
abstract: Bacteroides fragilis strains TAL2480 and TAL3636 were used to assess outer membrane permeability to various beta-lactam compounds. These strains were chosen because they possess beta-lactamases capable of hydrolysing all commonly employed beta-lactams except monobactams. The beta-lactamases are located in the periplasmic space and could be released by sonication and osmotic shock. Permeability was calculated by the method of Zimmerman & Rosselet (1977, Antimicrobial Agents and Chemotherapy 12, 368-72). The rank order of permeative ability (from fastest to slowest) was as follows: cephaloridine, imipenem, cefotaxime, cefoxitin, cefoperazone, nitrocefin, cephalothin, and latamoxef. Our results showed that ionic charge, hydrophobicity, and molecular weight influenced beta-lactam drug uptake by B. fragilis. These results are similar to findings for Escherichia coli, where increased negative charge and increased molecular weight are associated with decreased drug uptake. However, unlike E. coli, increased drug hydrophobicity, for a given charge and molecular weight of the drug, was associated with increased uptake by B. fragilis.
authors.affiliation: Department of Pathology, New England Medical Center Hospital, Boston, Massachusetts.
authors.forename: G J
authors.initials: GJ
authors.lastname: Cuchural
authors.forename: S
authors.initials: S
authors.lastname: Hurlbut
authors.forename: M H
authors.initials: MH
authors.lastname: Malamy
authors.forename: F P
authors.initials: FP
authors.lastname: Tally
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000494:pharmacology; D001441:Bacteroides fragilis / Q000378:metabolism*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003470:Culture Media; D008970:Molecular Weight; D012044:Regression Analysis; D013329:Structure-Activity Relationship; D001618:beta-Lactamases / Q000378:metabolism; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D047090:beta-Lactams; D001618:beta-Lactamases