Silver Nanoparticles Decrease the Viability of Cryptosporidium parvum Oocysts

Abstract

dOocysts of the waterborne protozoan parasite Cryptosporidium parvum are highly resistant to chlorine disinfection. We show here that both silver nanoparticles (AgNPs) and silver ions significantly decrease oocyst viability, in a dose-dependent manner, between concentrations of 0.005 and 500 g/ml, as assessed by an excystation assay and the shell/sporozoite ratio. For percent excystation, the results are statistically significant for 500 g/ml of AgNPs, with reductions from 83% for the control to 33% with AgNPs. For Ag ions, the results were statistically significant at 500 and 5,000 g/ml, but the percent excystation values were reduced only to 66 and 62%, respectively, from 86% for the control. The sporozoite/shell ratio was affected to a greater extent following AgNP exposure, presumably because sporozoites are destroyed by interaction with NPs. We also demonstrated via hyperspectral imaging that there is a dual mode of interaction, with Ag ions entering the oocyst and destroying the sporozoites while AgNPs interact with the cell wall and, at high concentrations, are able to fully break the oocyst wall.

Effect of Silver Nanoparticles on the Morphology of Toxoplasma gondii and Salmonella braenderup

“…Also, in Figure 2(c), the rupture of the membrane that encloses one of the sporocysts is observed; however, in Figure 2(c), this alteration is pronounced more strongly than Figure 2(b) (arrow). Although studies on the effect of AgNPs on T. gondii oocysts are not reported in the literature, similar results are shown in Cryptosporidium parvum, a human pathogen of the phylum Apicomplexa such as T. gondii, and Pamela Cameron et al evaluated the viability of oocysts exposed to AgNPs and silver ions [10], showed that both AgNPs and silver ions strongly decrease the viability of oocysts; however, the sporozoite/shell ratio was more affected with treatment with AgNPs possibly because sporozoites are destroyed by interaction with AgNPs.…”

“…Other studies report important applications of the use of AgNPs to affect protozoan parasites pathogenic for human health and that present mechanisms of resistance to chlorine treatments. Cameron et al demonstrated in their study breakdown of the cell structure of oocysts Cryptosporidium parvum when exposed to AgNPs, revealing a significant decrease in the viability of the oocysts of the parasite [10].…”

“…ere are several methods that affect the T. gondii parasite, for example, the cooking of foods at temperatures above 71°C or the conservation of them at temperatures below −20°C [8]; however, significant changes in the nutritional composition of some foods can occur in these temperature ranges [9]. Considering these limitations, other water purification alternatives have been proposed with the use of silver nanoparticles (AgNPs) due to their antimicrobial properties [10,11]. Currently, several studies describing procedures for the separation of T. gondii oocysts from water and soil samples are reported using immunomagnetic nanoparticles under laboratory conditions [12].…”

A comparison of methods to assess the antimicrobial activity of nanoparticle combinations on bacterial cells

“…coli , Pseudomonas spp . and the protozoan pathogen Cryptosporidium [ 12 , 36 , 37 ]. When comparing S .…”

The Quest for Novel Antimicrobial Compounds: Emerging Trends in Research, Development, and Technologies

“…They have been used in wound dressings and commercial antimicrobial socks. Recently, silver nanoparticles were shown to kill the chlorine-resistant apicomplexan parasite Cryptosporidium parvum [162]. Many pathogens have become resistant to conventional disinfectants, necessitating increasing dosage and mixtures of disinfectants that may produce harmful by-products.…”