Effect of resin disinfectants-I3 and -I5 on Giardia muris and Giardia lamblia

Abstract

The resin-I5 column developed in our laboratories rendered aqueous suspensions containing up to 5 X 10(4) cysts of Giardia muris or Giardia lamblia per ml incapable of excystation. The inhibition of excystation was effective at both 4 and 25 degrees C. The addition of Na2S2O3 to column eluates containing cysts appeared to partially reverse the disinfectant action, and the reversal was more pronounced at 4 degrees C than at 25 degrees C. In contrast, the rapid removal of cysts from the column eluates by centrifugation and filtration or the use of other reductants, notably cysteine and glutathione, did not similarly reverse the disinfectant properties of the column. Based on these data, we suggest that the disinfecting agent is acquired by the cyst in its passage through the resin column and that either the disinfecting agent or its reaction can be partially and specifically neutralized by Na2S2O3. We hypothesize that the time between disinfectant acquisition and activity is a function of the thickness of the Giardia cyst wall and consequently takes longer at the lower temperature. Nevertheless, resin-I5 appears to inactivate a larger number of cysts in a shorter period of time with lower residual halogen levels than do agents of other published methods.

Assessment of iodine-treated filter media for removal and inactivation of MS2 bacteriophage aerosols

“…(1980) proposed spontaneous dissociation of I 2 from the polyiodide–resin complex as one of three possible inactivation mechanisms of their iodinated resin filter in water treatment. In another study (Marchin et al. 1983), acquisition of I 2 by a cyst during passage through an iodinated resin column was hypothesized.…”

Influence of Selected Factors on the Survival Assessment and Detection of Giardia intestinalis DNA in Axenic Culture

“…Marchin et al [ 29 ] suggest that the disinfectant’s effect depends on the Giardia wall’s thickness, and therefore lasts longer at a lower temperature.…”

Comparison of animal infectivity and excystation as measures of Giardia muris cyst inactivation by chlorine

“…Difficulties encountered in obtaining adequate supplies of G. lamblia cysts for such studies led to the use of a model cyst system, employing the cysts of Giardia muris, which are infective for mice (13). Modified excystation procedures for G. muris cysts have been developed (14) and comparative disinfection data on G. lamblia and G. muris have been reported for chlorine (11) and other disinfectants (8,18). The adequacy of in vitro excystation for measuring loss of animal infectivity of cysts after exposure to disinfectants has not been established.…”