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MATRIX ASSISTED LASER DESORPTION/IONIZATION TIME OF FLIGHT MASS SPECTROMETRY BASED ANALYSIS OF GIARDIA LAMBLIA
Citation:
VILLEGAS, E., S. GLASSMEYER, M. W. WARE, S. L. HAYES, AND F. W. SCHAEFER. MATRIX ASSISTED LASER DESORPTION/IONIZATION TIME OF FLIGHT MASS SPECTROMETRY BASED ANALYSIS OF GIARDIA LAMBLIA. JOURNAL OF EUKARYOTIC MICROBIOLOGY. Allen Press, Inc., Lawrence, KS, 53(S1):S179-S-181, (2007).
Impact/Purpose:
1) Refine new, practical methods for the detection of CCL-related and emerging waterborne human protozoa.
2) Perform field tests of devices or methods that have been developed under this task.
3) Evaluate these methods or devices in a variety of water matrices and parasite concentrations.
This work in this task supports CCL2 and 3 and is expected to be completed by 9/07.
Description:
Giardia is the protozoan parasite that is the etiologic agent of giardiasis. This illness is the most common parasitic disease, estimated to infect 2.5 million people in the United States and up to 280 million people worldwide each year [8,19]. Symptoms of giardiasis range from asymptomatic to severe abdominal pain, chronic diarrhea, and in rare cases, death, with young children and immunocompromised individuals being at the greatest risk of serious illness [1,19]. Infection typically occurs through the fecal-oral route and has been documented to be associated with many waterborne disease outbreaks worldwide. A majority of these outbreaks occurred due to contamination of the drinking water supplies with untreated sewage.
There are at least six species of Giardia including Giardia lamblia (also known as Giardia duodenalis or Giardia intestinalis), which can infect a wide range of hosts including humans [4]. The current detection method employed to monitor the presence of Giardia cysts in surface and drinking water relies primarily on microscopic techniques that detect the presence of Giardia cysts in the sample, but the method is not species-specific nor does it determine cyst viability [18]. More recently, a PCR-based genotyping tool has been developed and used to identify the different Giardia spp. present in environmental water [17]. This technique however can be prone to contamination and thus other alternative approaches are currently being explored. In particular, matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) has been used to identify and classify bacteria [6], viruses, as well as protozoan parasites [12,13], although this approach has not been applied to study Giardia spp.
This manuscript describes a MALDI-TOF MS based approach that is used to characterize the mass spectral fingerprints of intact Giardia lamblia and Giardia muris cysts. This study identified common mass spectral peaks shared by the two species as well as peaks specific to G. lamblia and G. muris, which are useful in differentiating the two organisms. Additional analyses revealed that the mass spectral profiles of intact cysts consisted partly of peaks representing trophozoite-derived proteins, based on comparison with purified trophozoites. These results suggest the potential application of intact cell MALDI-TOF mass spectrometry as an alternative high throughput approach for species identification of Giardia spp.