In vitro activity of eight oral cephalosporins against Borrelia burgdorferi

Oral cephalosporins have not previously been extensively tested against larger numbers of Borrelia burgdorferi isolates derived from different clinical and geographical sources. This study investigated the in vitro activity of eight oral cephalosporins in addition to ceftriaxone and apramycin, against 17 isolates of the B. burgdorferi complex, including one B. valaisiana and one B. bissettii tick isolate. Minimal inhibitory concentrations and minimal borreliacidal concentrations providing 100% killing of the final inoculuin were determined by a standardised methodology in Barbour-Stoermer-Kelly-medium after 72 h of incubation. The rank order of potency was ceftriaxone > cefuroxime-axetil > cefixime, cefdinir > cefpodoxime > cefaclor > ceftibuten, loracarbef > cefetametpivoxil, apramycin. Our study demonstrates the superior in vitro effectiveness of ceftriaxone with good to excellent activity with the oral agents cefuroxime-axetil, cefixime and cefdinir against B. burgdorferi under strictly standardised test conditions. (C) 2003 Elsevier Science B.V. and the International Society of Chemotherapy. All rights reserved.