Efficacy of zymodemes of E. histolytica technique in an epidemiologic study and report of new zymodemes in Mexico.

OBJECTIVES

To determine the efficacy of zymodemes of E. histolytica technique in an epidemiologic study. To report the zymodemes for the first time described in Mexico. To report the main difficulties in the correct classification of zymodemes in this study. To describe the zymodemes identified in two evaluations done in 100 healthy individuals.

DESIGN

A cross-sectional survey and a cohort of healthy persons.

METHODS

We analyze the results of 1730 Robinson cultures performed in a cross-sectional survey done in the Municipality of Cadereyta, Queretaro, Mexico from October 1986 to August 1987. From positive cultures properly growth a Iysate was done and preserved in liquid nitrogen until the electrophoretic determination of 4 isoenzymes was done: EC 5.3.1.9. glucophosphate isomerase (GPI); EC 1.1.1.40 L-malate: NADP oxidoreductase (oxaloacetate decarboxylating) (ME); Ec 2.7.5.1 phosphoglucomutase (PGM); and EC 2.7.1.1 hexokinase (HK).

RESULTS

Of 1730 cultures 289 (16.7%) developed trophozoites, in 100 (34.6%) was possible to make lysate and zymodeme. There were 67 ZNP, 3 mixtures (ZP and ZNP) and 30 ZP. There were two patterns for the first time described in Mexico (XVII and XVIII) and 30 strains had a pattern different from the 20 already described by Sargeaunt. Results observed in 100 individuals measured twice. [table: see text] There were 9 subjects in which zymodemes were isolated twice: at the first time 5 PZ and 4 NPZ, at the second time 1 PZ and 8 NPZ. At first time all 9 had negative serology and the second time one carrier of NPZ became positive.

COMMENTS

In our study one tirth of Robinson cultures positive to trophozoites reached lysate. Efficacy of zymodemes and CPS is similar. We report for the first time in Mexico two non-pathogenic zymodemes (XVII and XVIII). We also report 30 zymodemes non-classified according to the standard proposed by Sargeaunt, one explanation for this feature is the possibility of zymodemes variability or new patterns. In endemic populations zymodeme pattern varies with time in asymptomatic carriers.