❞ كتاب Flow cytometric evaluation of selected antimicrobial efficacy for clearance of Anaplasma marginale in short-term erythrocyte cultures ❝

Flow cytometric evaluation of selected antimicrobial efficacy for clearance of Anaplasma marginale in short-term erythrocyte cultures

Flow cytometric evaluation of selected antimicrobial efficacy for clearance of Anaplasma marginale in shortterm erythrocyte cultures من كتب طب بيطرى

Flow cytometric evaluation of selected antimicrobial efficacy for clearance
of
Anaplasma marginale
in short-term erythrocyte cultures
J. F. COETZEE*
M. D. APLEY*,
K. M. KOCAN
&
D. E. JONES
à
*
Department of Veterinary Diagnostic
and Production Animal Medicine,
College of Veterinary Medicine,
Iowa State University,
Ames, IA, USA;
Department of
Pathobiology, Center for Veterinary Health
Sciences, Oklahoma State University,
Stillwater, OK, USA;
à
Department of
Veterinary Pathology, College of Veterinary
Medicine, Iowa State University, Ames,
IA, USA
Coetzee, J. F., Apley, M. D., Kocan, K. M., Jones, D. E. Flow cytometric evalu-
ation of selected antimicrobial efficacy for clearance of
Anaplasma marginale
in
short-term erythrocyte cultures.
J. vet. Pharmacol. Therap.
29,
173–183.
The tick-borne rickettsia,
Anaplasma marginale
, causes the economically
important cattle disease anaplasmosis. Once infected, cattle remain lifelong
carriers. Herein, we used flow cytometry to test the efficacy of three
antimicrobials; oxytetracycline, imidocarb and enrofloxacin against Virginia
(VGN) or Oklahoma (OK)
A. marginale
isolates in short-term erythrocyte
cultures. Parasite viability was assessed using the vital dye hydroethidine (HE),
which is detectable when living organisms convert HE to ethidium bromide.
Viability of
A. marginale
in selected cultures was determined by subinoculation
into susceptible calves. Data were analyzed by MANOVA, Tukey-Kramer honest
significant difference and Wilcoxon rank sum tests. Receiver operating
characteristic (ROC) analysis was used to correlate results with culture
infectivity. Enrofloxacin inhibited
A. marginale
in a dose dependent manner.
Surprisingly, higher concentrations of imidocarb were less effective than lower
concentrations against
A. marginale
with significant differences (
P
< 0.05)
observed between the two isolates. Oxytetracycline was the least active drug
tested. Cultures infected with the OK isolate exposed to 4.0
l
g/mL enrofloxacin
and those of the VGN and OK isolates exposed to 1.0
l
g/mL imidocarb were
sterilized. This is the first
in vitro
study demonstrating the efficacy of
enrofloxacin against
A. marginale
. Furthermore, these data indicate that flow
cytometry is a useful assay for screening antimicrobials against
A. marginale
.
(Paper received 16 November 2005; accepted for publication 17 February
2006)
Hans Coetzee, Department of Clinical Sciences, College of Veterinary Medicine,
Kansas State University, Manhattan, KS 66506–5601, USA. E-mail: jcoetzee@
vet.ksu.ed . المزيد..