Antimicrob Agents Chemother. 1996 Jun;40,6:1552-4. Eucaryotic cells protect Borrelia burgdorferi from the action of penicillin and ceftriaxone but not from the action of 44doxycycline and erythromycin. Brouqui P, Badiaga S, Raoult D. Unité des Rickettsies, Faculté de Médecine, Centre National de la Recherche Scientifique, Marseille, France. Despite appropriate antibiotic treatment, Lyme disease patients may have relapses or may develop chronic manifestations. The intracellular location of Borrelia burgdorferi suggests that antibiotics that penetrate cells will have greater efficiency. Doxycycline or erythromycin was more effective than penicillin or ceftriaxone in killing B. burgdorferi when the organism was grown in the presence of eucaryotic cell