title: Efficacy of amikacin combinations for nocardiosis.
abstract: We isolated five bacterial strains from patients diagnosed as having nocardiosis. Bacterial species were identified based on the similarities in the nucleotide sequences of 16S ribosomal RNAs. Three of the five strains were identified as Nocardia asteroids, but unexpectedly other two were Streptomyces hygroscopicus and Rothia dentocariosa. The latter two species are not members of the family Nocardiaceae. We investigated the susceptibilities of these five strains to the following nine antimicrobial agents: trimethoprim/sulfamethoxazole (TMP/SMX), minocycline (MINO), erythromycin (EM), amikacin (AMK), cefotaxime (CTX), faropenem (FRPM), imipenem (IPM), ciprofloxacin (CPFX), and sparfloxacin (SPFX). The minimum inhibitory concentration (MIC) ranges (mg/ml) were as follows: TMP-SMX, 4- > 32; MINO, 0.125-8; EM, < or = 0.016- > 32; AMK, 1-2; CTX, 0.063- > 32; FRPM, 0.063-16; IPM, 0.125-2; CPFX, 4-32; and SPFX, 0.5-16. Moreover, the synergistic effects of AMK in combination with each of TMP-SMX, MINO, EM, CTX, IPM, and SPFX were investigated by checkerboard synergy testing. No antagonism was recognized for the three N. asteroides strains. Synergistic and additive effects were observed for the combinations of AMK with CTX, IPM, or SPFX.
authors.affiliation: Department of Molecular Diagnostics, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan. kane2@mail.cc.tohoku.ac.jp
authors.forename: Keiji
authors.initials: K
authors.lastname: Kanemitsu
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kunishima
authors.forename: Tomoo
authors.initials: T
authors.lastname: Saga
authors.forename: Hideo
authors.initials: H
authors.lastname: Harigae
authors.forename: Shiho
authors.initials: S
authors.lastname: Ishikawa
authors.forename: Hiromu
authors.initials: H
authors.lastname: Takemura
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Kaku
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000583:Amikacin / Q000008:administration & dosage*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D002439:Cefotaxime / Q000008:administration & dosage; D002939:Ciprofloxacin / Q000008:administration & dosage; D004275:DNA, Ribosomal / Q000378:metabolism; D004359:Drug Therapy, Combination / Q000627:therapeutic use*; D004917:Erythromycin / Q000008:administration & dosage; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology; D006094:Gram-Positive Bacteria / Q000378:metabolism; D006801:Humans; D015378:Imipenem / Q000008:administration & dosage; D007769:Lactams / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D008911:Minocycline / Q000008:administration & dosage; D009615:Nocardia / Q000378:metabolism; D009617:Nocardia Infections / Q000188:drug therapy*; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D013302:Streptomyces / Q000378:metabolism; D013420:Sulfamethoxazole / Q000008:administration & dosage; D014295:Trimethoprim / Q000008:administration & dosage; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D004275:DNA, Ribosomal; D024841:Fluoroquinolones; D007769:Lactams; D012336:RNA, Ribosomal, 16S; D047090:beta-Lactams; D002939:Ciprofloxacin; D004917:Erythromycin; D015378:Imipenem; D000583:Amikacin; D014295:Trimethoprim; C107057:fropenem; D008911:Minocycline; D013420:Sulfamethoxazole; D002439:Cefotaxime; C061363:sparfloxacin