Genotyping of Giardia lamblia by multilocus sequence typing

Abstract number: P1705

Jansen R., Mank T.G., Ramparichan W., van de Craats A., Mittelberg P.

The intestinal parasite G. lamblia occurs worldwide and infects humans and animals. The infection route is expected to be the oral–faecal route between humans, and between humans and animals. To be able to trace the sources of infection and to elucidate the zoonotic potential of G. lamblia, a high resolution genotyping method is needed to trace individual strains of G. lamblia.

Objective: Development of a multilocus sequencing typing method (MLST) for G. lamblia.

Methods: The MLST uses sequence variation in the genes for ferredoxin (FD), glutamate dehydrogenase (GDH) and giardin (GD) to make a genetic fingerprint of G. lamblia strains. The method can be used on faeces from patients without the need to culture this fastidious parasite.

Results: The MLST was validated on a panel of hundred patients with well described medical and demographic data. The faeces samples were collected in the routine diagnostics during a three month period in the western urban area of the Netherlands. In a previous study the two genotypes assemblage A and B were determined of the G. lamblia strains of these patients. We found thusfar 9, 8, and 11 variants of the FD, GDH, and GD gene respectively. In the patient samples we have analysed 28 samples yet and found eight different MLST types, indicating that the method has a good discriminatory power. The MLST types were grouped by cluster analysis. As expected, there was a clear digotomy between the MLST types of G. lamblia strains with A or B assemblages of these patients, indicating the large genetic differences between these two genotypes. Moreover a clear correlation between MLST type and demographic data of the patients was found, indicating that the method is able to distinguish epidemiologically related groups.

Conclusions: The described MLST using three genes is able to distinguish G. lamblia strains from separate outbreaks. Currently, we are working on the implementation of two additional genes in the MLST sceme to increase the resolution of this genotyping method.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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