Effect of Job Design on Task Performance of Engineers of Public Utility Sector Organizations in North Western Province, Sri Lanka

This study investigated the prevalence and molecular characteristics of Vibrio spp. in farmed shrimp (Penaeus monodon) in Sri Lanka. A total of 170 shrimp samples (100 g of whole shrimp each) taken from individual ponds from 54 farms were collected 1 week prior to harvest from the North Western Province of Sri Lanka. Overall, 98.1% of the farms and 95.1% of the ponds were positive for Vibrio spp. in shrimp; at the pond level, V. parahaemolyticus (91.2%) was most common, followed by V. alginolyticus (18.8%), V. cholerae non-O1/non-O139 (4.1%), and V. vulnificus (2.4%). Multiple Vibrio spp. were detected in 20.6% of the ponds. None of the V. parahaemolyticus isolates (n = 419) were positive for the virulence-associated tdh (thermostable direct hemolysin) and trh (TDH-related hemolysin) genes. V. cholerae was confirmed by the presence of ompW, and all isolates (n = 8) were negative for the cholera toxin (ctxA) gene. V. cholerae isolates were serogrouped by PCR and identified as V. cholerae non-O1/non-O139. All four V. vulnificus strains, isolated from different ponds of two geographical regions, showed pathogenic potential; they belonged to vcgC sequence type, type B 16S rRNA genotype and contained a pilF polymorphism associated with human pathogenicity. The results of this study revealed the ubiquitous nature of vibrios in farmed shrimp. To minimize the potential risk of Vibrio infections due to handling or consumption of raw or undercooked seafood products, good manufacturing practices as well as proper handling and processing should be addressed.

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

PLoS ONE ◽

10.1371/journal.pone.0248510 ◽

2021 ◽

Vol 16 (3) ◽

pp. e0248510

Author(s):

Nuwan Gunarathna ◽

Anjalie Amarasinghe ◽

Sunil Wijesundara ◽

Devika Iddawela ◽

Susiji Wickramasinghe

Keyword(s):

Phylogenetic Analysis ◽

Sri Lanka ◽

Bayesian Analysis ◽

Molecular Characterization ◽

Its Region ◽

Water Bodies ◽

Internal Transcribed Spacer Region ◽

Western Province ◽

The North ◽

North Western

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.

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