title: Antimicrobial susceptibility of Ehrlichia phagocytophila.
abstract: Human granulocytic ehrlichiosis is a recently described disease caused by an obligate intracellular gram-negative organism recently named Ehrlichia phagocytophila. To expand our knowledge of the susceptibility of E. phagocytophila, we tested six New York State isolates for susceptibility to 12 antimicrobials using an HL-60 cell culture system. All of the isolates were susceptible to doxycycline (MIC, < or =0.125 microg/ml; minimum bactericidal concentration [MBC], 0.125 to 0.5 microg/ml), rifampin (MIC, < or =0.125 microg/ml; MBC, < or =0.125 microg/ml), ofloxacin (MIC, < or =2 microg/ml; MBC, < or =2 microg/ml), levofloxacin (MIC, < or =1 microg/ml; MBC, < or =1 microg/ml), and trovafloxacin (MIC, < or =0.032 microg/ml; MBC, < or =0.032 microg/ml). Isolates were uniformly resistant to amoxicillin, ceftriaxone, erythromycin, azithromycin, clarithromycin, and amikacin. For one strain, the MBC of chloramphenicol was < or =8 microg/ml. These data suggest that quinolone antibiotics and rifampin may be alternative agents for patients with intolerance to tetracyclines.
authors.affiliation: Division of Infectious Diseases and Department of Medicine, New York Medical College, Valhalla, New York 10595, USA. Harold_Horowitz@nymc.edu
authors.forename: H W
authors.initials: HW
authors.lastname: Horowitz
authors.forename: T C
authors.initials: TC
authors.lastname: Hsieh
authors.forename: M E
authors.initials: ME
authors.lastname: Aguero-Rosenfeld
authors.forename: F
authors.initials: F
authors.lastname: Kalantarpour
authors.forename: I
authors.initials: I
authors.lastname: Chowdhury
authors.forename: G P
authors.initials: GP
authors.lastname: Wormser
authors.forename: J M
authors.initials: JM
authors.lastname: Wu
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004536:Ehrlichia / Q000187:drug effects* / Q000302:isolation & purification; D016873:Ehrlichiosis / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests
chemical_list: D000900:Anti-Bacterial Agents