Isolation, molecular characterization and phylogeny of Naegleria species in water bodies of North-Western Province, Sri Lanka

Abstract

Background The inland freshwater bodies in the North-Western Province of Sri Lanka have ideal environmental conditions for the Naegleria species. Therefore, the presence and prevalence of Naegleria species in the water bodies of North-Western Province were determined by molecular characterization and phylogenetic analysis in this study. Methods A total of 104 water bodies were selected from Kurunegala and Puttalam districts in the North-Western Province of Sri Lanka. Mean turbidity, pH, and temperature were recorded in each water body from three selected site. Centrifuged samples were cultured on non-nutrient agar plates with Escherichia coli. Enflagellation test positive isolates were subjected to DNA extraction and polymerase chain reaction using genus and species-specific primers targeting the internal transcribed spacer region (ITS) and Mp2CL5 gene. Phylogenetic analysis was performed using Bayesian and maximum likelihood (ML) methods. Results The prevalence of Naegleria species and N. fowleri in the study area were 23.07% and 1.92%. The prevalence of Naegleria species and the physicochemical parameters of the water bodies showed no significant correlation. Bayesian analysis of the ITS region revealed the Naegleria Sri Lankan (SL) isolates 1, 3, and 4 in a single clade separated from the 2 and 5. Furthermore, Bayesian analysis identified isolates 2 and 5 in the same clade with Naegleria sp. samples and N. Philippinensis forming a sister clade. However, in the ML tree, all isolates were in the same clade with Naegleria sp. samples and N. Philippinensis. Conclusions The present study reports the first isolation of pathogenic N. fowleri from Sri Lanka. Based on Bayesian analysis, SL isolates 2 and 5 form a separate clade from 1, 3, and 4. However, in ML analysis, all isolates are grouped in one clade with Naegleria sp. samples and N. philippinensis. Further investigations are required to confirm these findings.

Spatial and physicochemical assessment of groundwater quality index in the urban coastal region of Sri Lanka

“…to Galhenage et al (2021), turbidity ranged from 1.6 to 164 NTU, while Gunarathna et al (2021) found that turbidity ranged from 44 to 723 NTU. Furthermore, the study found that the mean turbidity in ground water was much higher than in surface water (Gunarathna et al 2021).…”

Spatial and physicochemical assessment of groundwater quality in the urban coastal region of Sri Lanka

“…As a result, it's unlikely to be suitable for drinking. Several earlier investigations have found that the turbidity in the groundwater of Puttlam district was much higher than the WHO and SLS permitted values.According to Galhenage et al (2021), turbidity ranged from 1.6 to 164 NTU, while Gunarathna et al (2021) found that turbidity ranged from 44 to 723 NTU. Furthermore, the study found that the mean turbidity in ground water was much higher than in surface water (Gunarathna et al 2021).…”