Anthelmintic resistance in worms infecting animals

It is becoming more essential to identify and recognize the phenotypes of anti-parasitic drug-resistant isolates. Current molecular methods of doing so are restricted. In this paper, we showcase a microfluidic bioassay to measure phenotype using parameters of nematode locomotion, using larvae of the animal parasite Oesophagostomum dentatum. Parameters of sinusoidal movement, including propagation speed, wavelength, wave amplitude, and oscillation frequency, were dependent on the levamisole-sensitivity of the parasitic nematode isolate. The levamisole-sensitive isolate had a mean wave amplitude of 135 μm; larger than the 123 μm observed in the levamisole-resistant isolate. The mean wavelength of the levamisole-sensitive isolate was 373 μm, less than the 393 μm of the levamisole-resistant isolate. The propagation velocity of the two isolates showed no significant difference, but were both inhibited by levamisole in a concentration-dependent manner from 0.5 μM, with the levamisole-sensitive isolate having an EC50 of 3 μM, and the levamisole-resistant isolate having an EC50 of 10 μM. This microfluidic technology improves existing nematode migration tests by providing more in-depth quantification as well as increased drug sensitivity. It is anticipated that the bioassay will enable research on resistance to other anthelmintic drugs that impact locomotion.

Baozhen Chen et al, Microfluidic bioassay to characterize parasitic nematode phenotype and anthelmintic resistance, Parasitology (2011), 138, 80–88.

doi:10.1017/S0031182010001010