Quantitative assessment of Naegleria fowleri and fecal indicator bacteria in brackish water of Lake Pontchartrain, Louisiana

摘要

Brackish water samples from Lake Pontchartrain in Louisiana were assessed for the presence of pathogenic amoebaNaegleria fowleri, which causes primary amoebic meningoencephalitis (PAM). In our study, quantitative polymerase chain reaction (qPCR) methods were used to determineN. fowleri,E. coli, and enterococci in water collected from Lake Pontchartrain.N. fowleritarget sequence was detected in 35.4% (56/158) of the water samples from ten sites around the lake. Statistically significant positive correlations betweenN. fowlericoncentration and water temperature as well asE. coli(qPCR) were observed. Multiple linear regression (MLR) model shows seasonal factor (summer or winter) has significant effect on the concentration ofN. fowleri,E. coliand enterococci (qPCR) concentration. Significant positive relationships betweenE. coliand enterococci was observed from both qPCR (r=0.25) and culture based method (r=0.54). Meanwhile, significant positive correlation between qPCR and culture based methods for enterococci concentration was observed (r=0.33). In our study, water temperature andE. coliconcentration were indicative ofN. fowlericoncentrations in brackish water environment. Future research is needed to determine whether sediment is a source ofN. fowlerifound in the water column.