Characterization of Giardia lamblia groups A and B from North India by isoenzyme and random amplified polymorphic DNA analysis

Giardia lamblia ( syn. G. intestinalis) infection in young adults leads to acute/chronic diarrhea in some individuals and is asymptomatic in others. R ecently, G. lamblia strains have been characterized as group A (symptomatic ) and group B (asymptomatic or control) by advanced isoenzyme and molecular biology studies. In the present brief pilot study, ten G, lamblia isolates obtained from five symptomatic (group A) and five asymptomatic (group B) p ersons were characterized by isoenzyme and random amplified polymorphic DNA (RAPD) analysis. Isoenzyme analysis demonstrated remarkable homogeneity in seven enzyme patterns, the exception, being that of phosphoglucomutase? fo r which two zymodemes (I and III) were observed. In contrast, RAPD analysis showed homogeneity for eight primers; exceptions were two primers, A(02) a nd B-05 which separated roup A G. lamblia isolates into two rapdemes (A(R1) and A(R2)) and group B G, lamblia isolates into four rapdemes (B-R1 B-R2, B-R3 and B-R4) Further phenetic analysis showed average genetic distances o f 0.105 within group A and 0.121 within group B G. lamblia isolates accordi ng to Jaccord's distance scale, which suggests that both lineages appear to consist of a range of variants with no significant (P < 0.05) genetic dive rsity. The two techniques demonstrated a positive association with regard t o differentiation between group A and group B G. lamblia isolates. These ve ry preliminary results indicate that RAPD analysis could be a potentially u seful substitute for isoenzyme analysis.