Occurrence of free-living amoebae in streams of the Mexico Basin

Abstract

Free-living amoebae (FLA) are protozoa that are widely distributed in nature. They are important in the cycling of nutrients in aquatic food chains, but their distribution in natural aquatic environments is not well known. We conducted a survey to determine the presence and distribution of FLA and their relation to some physicochemical parameters in streams of the Mexico Basin in Central Mexico. Thirty-two sites from 18 streams were sampled. Samples were centrifuged and cultured onto NNA-media to isolate amoebae. Identifications were based on morphology. The pathogenicity of Acanthamoeba isolates was tested. Oxygen saturation, temperature, pH, specific conductance, water flow, dissolved reactive phosphorus, nitrites, nitrates, ammonia, dissolved inorganic nitrogen and coliforms were determined. One hundred-and-twenty FLA representing 18 genera were identified. The most frequent genera were Vannella, Rosculus and Acanthamoeba. The frequency of potentially pathogenic FLA was low and only 3 Acanthamoeba isolates were invasive in mice. The highest species richness of FLA was found in streams located into agriculture activity areas and those close to small villages that discharge wastewater into them. Water temperatures were always below 17°C. Oxygen saturation and pH were within the limits for the growth of most FLA. The presence of Acanthamoeba and Naegleria was low; nevertheless, they include potentially pathogenic species and can act as vectors and reservoirs for microbial pathogens and can produce human infections.

Xenic Cultivation and Genotyping of Pathogenic Free-Living Amoeba from Public Water Supply Sources in Uganda

“…This is in agreement with previous studies that indicate that T2 Acanthamoeba genotype is mainly found in the environment and is phylogenetically related to T6 and they have also been both isolated from clinical AK cases in humans [40]. Acanthamoeba genotype T11 is closely related to T4 and has been found to also cause AK [33]. Acanthamoeba of T4 genotype is reported as the most commonly encountered T-genotype group in both environmental water and clinical samples and also the most diverse [33].…”

“…that were higher in the dry season. Most waterborne parasites increase in number during the rainy season due to contamination of the water sources with sewage, soil, and other organic matters from water run-off [5,33]. Tap water had a higher prevalence of FLA than the natural water source.…”

Contamination of Swimming Pools and Park Ponds to Free Living Amoebae in Tehran – Iran

“…The page key is based on morphological character of free living amoebae such as trophozoites shape, pseudopodia shape and amoebae nucleus, endo and ecto-cysts in the cystic form. These criteria could lead to identification of amoeba at the family and genus level [11]- [13]. This study indicated the considerable contamination of recreational water sources in Tehran, Iran with free living amoebae.…”

Detección por cultivo de amibas de vida libre en fuentes de agua superficiales de la Cd. de Reynosa, Tamaulipas

“…En México, existe una falta de reportes sobre detección de estos organismos (Lares-Villa & Hernández-Peña, 2010;Bonilla-Lemus et al, 2014). Este abordaje en el estado de Tamaulipas es el primero de su clase y el primero en describir presencia de amibas de vida libres consideradas patogénicas.…”