Comparison ofGiardia isolates from different laboratories by isoenzyme analysis and recombinant DNA probes

Abstract

A total of 13 new Giardia isolates were established in axenic culture. All of the new isolates were obtained by excystation of Giardia cysts from the feces of patients in Dutch hospitals. These isolates were subjected to isoenzyme and DNA analysis together with isolates from Poland, Belgium, and various other parts of the world. Isoenzyme analysis revealed that nearly all of the newly established isolates exhibited unique zymodemes. Isolates obtained from individuals from Belgium and Poland, on the other hand, displayed single zymodemes. Genomic DNA libraries were constructed from isolates belonging to the latter two zymodemes; specific and common recombinant DNA clones were selected from these libraries. Differential screening revealed that the two isolates had only 80% of the clones in common. Restriction-fragment-length polymorphism analysis using three different probes together with two synthetic probes that are complementary to Giardia structural protein genes led to the separation of all isolates into two major groups; within these groups, a further division could be made by application of other techniques or probes. The results of DNA analysis and zymodeme classification were in general agreement; in the present report they are compared with the data in the literature and discussed.

Molecular genetic analysis ofGiardia intestinalisisolates at the glutamate dehydrogenase locus

“…The 2 genetic groups of G. duodenalis denned in Europe by Homan et al (1992) correspond precisely with the 2 major genetic assemblages defined by allozymic analysis of human-derived isolates from Australia (Andrews et al 1989;Mayrhofer et al 1995). Without exception, isolates typed in the Bilthoven laboratory as 'Polish' showed identity in both assays with Australian isolates belonging to genetic Assemblage A (Mayrhofer et al 1995).…”

“…Conversely, isolates typed as 'Belgian' showed identity in the gdh assay with Australian isolates belonging to genetic Assemblage B (Mayrhofer et al 1995). The concordance of the allozymically defined groups (Andrews et al 1989), the groups defined by the 2 PCR assays and the groups defined by Homan et al (1992) are summarized in Fig. 4.…”

“…This will aid production of a meaningful systematics for the genus and provide a sound genetic basis for comparison of ultrastructural, biochemical, immunological and clinical characteristics in Giardia of medical and veterinary significance. We describe herein comparative data from Australian and European isolates which match and define further the genetic groups described by Andrews et al (1989), Homan et al (1992) and Mayrhofer et al (1995).…”

“…The latter panel comprised cloned axenic cultures of isolates Ad-1, Ad-2, Ad-3, Ad-6 and BRIS/83/ HEPU/136 (the last obtained from Dr P. Boreham, Queensland Institute of Medical Research, Brisbane), uncloned axenic cultures of isolates Ad-28 and Ad-45; and isolates Ad-7, Ad-19, Ad-52, Ad-62 and Ad-121 which were propagated by growth in suckling mice (Andrews et al 1989Mayrhofer et al , 1995Ey et al 1992. Axenic isolates were cultured at 37 °C in modified TYI-S-33 medium as described (Andrews, Chilton & Mayrhofer, 1992;Homan et al 1992). Isolates used as standards for the allozyme-defined genetic groups I, II, III and IV of Andrews et al (1989) were clones of Ad-1, Ad-3 and Ad-6 (all group I), Ad-2 and Bris-136 (both group II) (Ey et al 1992, 19936), and uncloned isolates Ad-19 (group Ill-like), Ad-7, Ad-28 and Ad-52 (group IV-like), as described elsewhere (Mayrhofer et al 1995) and indicated in Table 1 .The geographic origin (actual or deduced) and host origin of each isolate is indicated in Table 1.…”

“…When the tsa417/tspll PCR was applied to the 19 isolates typed (Homan et al 1992) as 'Belgian', only 2 isolates (BAH-8 and CP-117) yielded any detectable 0-52 kb product. However, in both cases this was present in trace amounts only, together with a faintly stained 0 3 7 k b product (Table 1).…”