In vitro evaluation of the amebicidal activity of Buddleia cordata (Loganiaceae, H.B.K.) on several strains of Acanthamoeba.

Infectious diseases produced by free-living amoebae from the genus Acanthamoeba have been recently recognized. The need for antiamebic compounds is urgent as the occurrence of these diseases is being registered more frequently since the late sixties. We screened the aqueous and methanolic extract of a plant used by folk medicine (Buddleia cordata) against eye and skin inflammation for antiamebic activity. We tested the extracts on 29 strains of free-living amoebae, with the result that they were amebostatic for 14 and 15 strains, respectively. We obtained linarin and vanillic acid from the extracts, but only linarin was amebostatic to all the strains and vanillic acid had no activity. However, acetyl vanillic acid had similar effects on amoebae to linarin. Threshold values of these two active compounds ranged from 31.25 microg/ml to 4 mg/ml and from 31.25 microg/ml to 8 mg/ml for linarin and acetyl vanillic acid, respectively. These differences in threshold values were observed even on several strains belonging to the same species (as in the case of A. castellanii and A. polyphaga) indicating the need of susceptibility testing for each clinical isolate of free-living amoebae.

Prevalence of pathogenic Acanthamoeba (Protozoa:Amoebidae) in the atmosphere of the city of San Luis Potosi, Mexico.

Several species of pathogenic Acanthamoeba cause infections to humans, but amoebic keratitis is more frequently found than any other due to the increasing number of contact lens wearers in the world. Cysts and trophozoites of these amebas are airborne and may pollute water from the air. We investigated the proportion of pathogenic Acanthamoeba from the atmosphere of the city of San Luis Potosi. Samples were taken by the impinger method, every month during one year. We isolated 23 strains of Acanthamoeba, 61% of them were non-pathogenic, 31% were non-pathogenic with invasive capacity and 8% were pathogenic to mice. Almost 40% of these strains represent danger of infections to humans. The isolations were more abundant during the dry season in the south (urban) and west (suburban) stations, which means that the sanitary conditions around stands may enhance the proportion of pathogenic strains in the surroundings.

Amoebological study of the atmosphere of San Luis Potosi, SLP, Mexico.

A one year round survey was conducted for isolation of free living amoebae (FLA) in the city of San Luis Potosi, (SLP), Mexico, which is placed in a desert environment. Samples were taken by modified impinger method and cultivated in laboratory conditions for FLA isolation following a week period of rehidration. 57 strains were isolated, 39% belonged to Acanthamoeba genus (which is important because it bears opportunistic pathogens that produce amoebic keratitis and granulomatous amoebic encephalitis in humans), 16% to Hartmannella, 9% to Vahlkampfia and the other proportion was divided among 6 other genera. The isolations were more abundant during dry season and the main genera were present in all four stands. The difference among them was the species variety which is discused as connected with abundance of organic wastes and lack of urbanization near the stations.