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Published on: February 4, 2018
The identification of Naegleria fowleri from water and soil samples by nested PCR
Rebecca C Maclean1, Dennis J Richardson, Robin LePardo
1Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298, USA.
Abstract:
Naegleria fowleri is the causative agent of primary amebic meningoencephalitis (PAM), a disease of the central nervous system. Healthy humans sporadically become infected with N. fowleri and develop fatal PAM after recreational or work exposure to freshwater; accordingly, there is a need for monitoring the presence of pathogenic ameboflagellates in public freshwater. The present study was conducted to determine whether a nested PCR assay could be used for the detection of N. fowleri in freshwater habitats. Water samples were collected in Virginia, since Naegleria has been isolated previously in this state. Additionally, the occurrence of N. fowleri in samples from Connecticut was investigated since neither N. fowleri nor PAM has been reported from this region. PCR analysis demonstrated that two of four samples from Virginia were positive for N. fowleri without intervening culture while 15 of 86 samples from Connecticut were positive that had been enriched by culture. This constitutes the first report of N. fowleri from Connecticut waters. These results indicate that the PCR assay can be utilized to detect N. fowleri in water and soil collected from the environment.
Insights
A nested PCR assay effectively detects Naegleria fowleri, the cause of primary amebic meningoencephalitis (PAM), in freshwater. This method identified the pathogen in Virginia and for the first time in Connecticut, aiding environmental monitoring.
Area of Science:
- Environmental microbiology
- Molecular biology
- Public health
Background:
- Naegleria fowleri causes fatal primary amebic meningoencephalitis (PAM) in humans.
- Infection occurs through freshwater exposure, necessitating environmental monitoring for this pathogen.
- Current detection methods may be limited in environmental surveillance.
Purpose of the Study:
- To evaluate a nested PCR assay for detecting Naegleria fowleri in freshwater.
- To assess the presence of Naegleria fowleri in water bodies in Virginia and Connecticut.
- To establish a reliable method for identifying pathogenic ameboflagellates in environmental samples.
Main Methods:
- Water samples were collected from freshwater habitats in Virginia and Connecticut.
- A nested PCR assay was employed for the direct detection of Naegleria fowleri DNA.
- Some samples underwent enrichment by culture prior to PCR analysis.
Main Results:
- Naegleria fowleri was detected in 2 of 4 samples from Virginia using PCR without prior culture.
- The pathogen was identified in 15 of 86 samples from Connecticut after culture enrichment.
- This study marks the first documented occurrence of Naegleria fowleri in Connecticut waters.
Conclusions:
- The nested PCR assay is a viable tool for detecting Naegleria fowleri in environmental water samples.
- The findings highlight the presence of Naegleria fowleri in previously unreported regions.
- Environmental PCR offers a valuable approach for monitoring public freshwater for pathogenic amebae.
