Members of the genus Naegleria are free-living amoebae that are widely distributed in water and soil environments. Moreover, Naegleria fowleri is a pathogenic amoeba species that causes a fatal disease in the central nervous system known as primary amoebic meningoencephalitis (PAM) in humans. Since most reported infections due to N. fowleri are reported in recreational waters worldwide, this study was aimed to describe the presence of these amoebic genus in Mexicali Valley irrigation channels of recreational use. A total of nine water samples were collected and processed by triplicate, in nine different sites of the Valley. After filtering and culturing the samples, plates were examined, and the observed amoebae were morphologically identified at the genus level. In addition, the pathogenicity of these amoebic isolates was checked, and molecular characterization was performed by PCR/sequencing. The results revealed the presence of Naegleria spp. in all the channels sampled. Finally, molecular identification confirmed the presence of five different species of Naegleria: N. fowleri, N. australiensis, N. gruberi, N. clarki and N. pagei. The presence of these protists, particularly N. fowleri, should be considered as a potential human health risk in the region.

Few studies have been conducted in the cooling systems of power plants; they have focused on Naegleria fowleri, leaving a gap in the knowledge of other pathogenic free-living amoebae in this environment. The objective of this study was to determine the occurrence of saline-tolerant pathogenic Acanthamoeba in a geothermal power plant. The identification of isolated amoebae at genus level was carried out, observing their morphological characteristics; the determination of genotype and species of Acanthamoeba was performed via molecular biology (PCR). Water temperature ranged from 18 to 43 °C and conductivity from 4.0 × 10⁴ to 8.7 × 10⁴ μS/cm; this last value was greater than the seawater value. Only five amoeba genera were found. Acanthamoeba was in all the sampling sites, showing high saline tolerance. The high temperature, but mainly high conductivity, were the environmental conditions that determined the presence of pathogenic free-living amoebae in the hot water. All the strains of Acanthamoeba culbertsoni killed the mice, having a mortality of 40 to 100%. Acanthamoeba genotypes T10 and T5 were identified, T10 is rarely isolated from the environment, while T5 is more frequent. This is the first time that genotypes T5 and T10 have been reported in the environment in Mexico.

México ocupa el primer lugar a nivel mundial en consumo de agua embotellada per cápita. Esto se debe a la desconfianza que existe en la población acerca de la calidad del agua de grifo y el acceso es igual e intermitente a los sistemas de agua potable. La contaminación del agua embotellada por bacterias se ha reportado alrededor del mundo, pero no se ha investigado la presencia de otros microorganismos, como las amibas de vida libre patógenas, que pueden estar en el ambiente, pero también pueden causar infecciones en el humano. El objetivo de la presente investigación fue determinar la presencia de las amibas de vida libre patógenas en agua embotellada. Se analizó el agua de 47 garrafones de 20 litrosque se venden en el Área Metropolitana de la Ciudad de México. Se analizaron 2 muestras de cada garrafón, una al abrirlo y otra a la mitad del volumen. Las amibas se determinaron por cultivo en el medio agar no nutritivo y se identificaron por morfología. Treinta y un garrafones fueron positivos para la presencia de las amibas, de estos 21 fueron de purificadoras locales y 10 de purificadoras grandes. Se encontraron 15 especies de amibas, la mayoría de ellas no son patógenas, solamente del del género Acanthamoeba han reportado como patógenas oportunistas, lo que representa un riesgo para la salud de las personas con defensas bajas. Por lo que además de la calidad bacteriológica y fisicoquímica, también sedebería de tomar en cuenta la calidad amebológica del agua embotellada.