Abstract |
Ten trypanosome isolates were collected at random from cattle at Ghibe, Ethiopia, in February 1993 and all shown to be savannah-type Trypanosoma congolense. When inoculated into naïve Boran (Bos indicus) calves, all 10 isolates were resistant to diminazene aceturate ( Berenil), isometamidium chloride ( Samorin) and homidium chloride ( Novidium) at doses of 7.0 mg/kg body weight (b.w.), 0.5 mg/kg b.w. and 1.0 mg/kg b.w., respectively. In order to determine whether this multiple-drug resistance was expressed by individual trypanosomes, clones were derived from two of the isolates and characterised in mice for their sensitivity to the three compounds; by comparison to drug-sensitive populations, the two clones expressed high levels of resistance to all 3 trypanocides. In experiments to characterise the uptake kinetics of [14C]- Samorin, the maximal rates of uptake (Vmax) for 4 Ghibe isolates ranged from 9.2 to 15.0 ng/10(8) trypanosomes/min. In contrast, Vmax for the isometamidium-sensitive clone T. congolense IL 1180 was 86.7 +/- 8.6 ng/10(8) trypanosomes/min. Lastly, molecular karyotypes were determined for eight isolates: seven different chromosome profiles were observed. These data indicate that in February 1993 there was a high prevalence of drug-resistant trypanosome populations with different chromosome profiles in cattle at Ghibe. Since a similar situation existed at the same site in July 1989, this suggests that the drug-resistance phenotype of trypanosomes at Ghibe had not altered over a 4 year period.
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Authors | W Mulugeta, J Wilkes, W Mulatu, P A Majiwa, R Masake, A S Peregrine |
Journal | Acta tropica
(Acta Trop)
Vol. 64
Issue 3-4
Pg. 205-17
(Apr 15 1997)
ISSN: 0001-706X [Print] Netherlands |
PMID | 9107367
(Publication Type: Journal Article)
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Chemical References |
- Phenanthridines
- Trypanocidal Agents
- isometamidium chloride
- Ethidium
- Diminazene
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Topics |
- Animals
- Biological Assay
- Cattle
- Chromosomes
(genetics)
- Diminazene
(administration & dosage, pharmacology, therapeutic use)
- Drug Resistance, Microbial
(genetics)
- Drug Resistance, Multiple
(genetics)
- Ethidium
(administration & dosage, pharmacology, therapeutic use)
- Ethiopia
- Karyotyping
- Mice
- Microbial Sensitivity Tests
- Phenanthridines
(administration & dosage, pharmacology, therapeutic use)
- Rats
- Trypanocidal Agents
(administration & dosage, pharmacology, therapeutic use)
- Trypanosoma congolense
(drug effects, genetics)
- Trypanosomiasis, African
(drug therapy, genetics, veterinary)
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