Table 1. In vitro Susceptibility and Clinical Efficacy of Selected Antibiotic Drugs Used for the Treatment of  Ehrlichial Infections. Susceptible Breakpoint Values have not been Established for Ehrlichiae and Anaplasmae. 

ND not done, DOXY doxycycline, CHLOR chloramphenicol, RIF rifampin, TCN tetracycline or oxytetracycline

MIC minimum inhibitory concentration

*  Published in vitro antibiotic susceptibility test results

†  Late therapy has resulted in chronic infections

¶  Doxycycline is toxic to horses  in therapeutic concentrations

Table 2. Antibiotic Recommendations  [Download PDF]

1.  Doxycycline hyclate: Effective

                       Adults:  100 mg orally or intravenously at 12 hour intervals.

                       Children:   4.4 mg/kg/day orally or intravenously in two divided doses.

                       Duration of therapy HME: 7-10 days, or at least 3 days after fever has abated.

                       Duration of therapy HGE: 14 days.

                       Duration of therapy Sennetsu fever: 7-10 days.

                       Duration of therapy E. ewingii infection. 7-10 days, or at least 3 days after fever has abated.

2.      Tetracycline hydrochloride: Effective

                       Adults: 500 mg orally in four divided doses.

                       Children: 25-50 mg/kg/day orally in two to four divided doses, or

                                    0.6-1.2 g/m2/day in two to four divided doses.

                       Duration of therapy: As for doxycycline hyclate.

3.      Rifampin: Probably effective

                  Adults: 300 mg orally twice daily.

                       Children: 10 mg/kg/day orally twice daily.

                       Maximum individual dose 300 mg each.

                       Duration of therapy: Unknown (7-10 days?)