In vitro Effects of Certain Drugs on Strongyloides.

Abstract

The success attendant on the oral administration of gentian violet and crystal violet in eradicating or greatly reducing Strongyloides stercoralis in the human host (de Langen, 1 Faust 2 ) as well as in other primates suggested the desirability of testing in vitro the strongyloidicidal properties of several therapeutics. While it was not possible to secure living parasitic Strongyloides for this purpose, the several successive stages of the free-living generation of an indirect type of Strongyloides fülleborni from the red-spider monkey, Ateles geoffroyi, were available. These organisms had been cultured in undiluted moist feces. At the appropriate time, when active free-living males and females, rh₂, RH₂ and f₂ larvae were both numerous and active, the nematodes were drawn off in a few drops of clear water by means of the Baermann technic.

In the first instance these several stages were placed in 0.1% of each of the following reagents: crystal violet (cv); acriviolet (acv); acriflavine (acf); mercurochrome (mc), and hexyl resorcinol (hr). The results of this test are shown in the accompanying table.

In view of these results, showing the high potency of hexyl resorcinol in the dilution used, the organisms were then tested in 0.01, 0.002 and 0.001% dilutions of this drug. The tests in this case showed that the 0.01 dilution was almost as potent as the 0.1 dilution, while the 0.002 dilution required 20 minutes to kill the worms. The 0.001 dilution was not effective under 1 hour; in other words, it was about as lethal as 0.1% crystal violet.