Isolation and Identification of Naegleria Species in Irrigation Channels for Recreational Use in Mexicali Valley, Mexico

Abstract

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.

Extensive Cryptic Diversity and Ecological Associations Uncovered among Mexican and Global Collections of Naegleria and Vermamoeba Species by 18S Ribosomal DNA, Internal Transcribed Spacer, and Cytochrome Oxidase Subunit I Sequence Analysis

“…The sequence of strain TA37-1 was identical to those of several Chinese, Japanese, and Iranian isolates, classified as N. clarki. However, their sequences are not identical to the type strain BG6, which forms a distinct sublineage within the N. clarki complex, together with the Mexican reference sequences CRET1 and CRET2, isolated from irrigation channels in Mexicali, Baja California ( 36 ). Consequently, TA37-1 was classified as Naegleria sp.…”

“…This regional-scale diversity was analyzed in the context of comprehensive sets of nuclear (18S rDNA and ITS) and mitochondrial (COI) sequences found in GenBank from isolates collected worldwide. In Mexico, studies using molecular sequence data to analyze the diversity of FLA have focused on amoebae of clinical importance like Acanthamoeba ( 65 ), Balamuthia mandrilaris ( 66 ), Naegleria ( 36 , 67 ), and Vermamoeba vermiformis ( 67 ). Most of them used genus- or species-specific primers targeting the 18S rRNA or ITS regions, biasing and limiting the assessment of the diversity of FLA in the sampled habitats.…”

Prevalence of free-living amoebae in swimming pools and recreational waters, a systematic review and meta-analysis

“…T15 Salehi et al 2019 Iran Park pool and swimming pool 14 12 Morphology, PCR Acanthamoeba T2, T4, T5, and T11 Attariani et al ( 2020 ) Iran Swimming pool 42 3 Morphology, PCR Acanthamoeba spp. Ballares et al 2020 Philippines Recreational water (6) 16 6 Morphology, PCR Acanthamoeba T4, Acanthamoeba T5, and Acanthamoeba T9 Bonilla-Lemus et al 2020 Mexico Recreational water (9) 9 9 Morphology, PCR N. australiensis , N. gruberi , N. fowleri , N. clarki , and N. pagei Değerli et al ( 2020 ) Turkey Thermal swimming pool 434 148 Morphology, PCR Acanthamoeba spp. and Naegleria spp.…”

Primary Amoebic Meningoencephalitis by Naegleria fowleri: Pathogenesis and Treatments

“…PAM is a hemorrhagic-necrotizing meningoencephalitis caused by N. fowleri and is seen mainly in immunocompetent children and young adults [ 12 ]. This infection occurs most frequently during the summer months when the water temperature is adapted to the thermal needs of the amoeba and people engage in recreational water activities [ 16 ].…”

“…Thenceforth, PAM has been reported in multiple countries, with an estimate of 400 victims worldwide. However, the total number of cases is unknown and could be greater due to misdiagnosis or unreported cases [ 3 , 4 , 16 ].…”