Biofilm Roughness Determines Cryptosporidium parvum Retention in Environmental Biofilms

Abstract

<jats:title>ABSTRACT</jats:title><jats:p>The genus<jats:named-content content-type="genus-species">Cryptosporidium</jats:named-content>is a group of waterborne protozoan parasites that have been implicated in significant outbreaks of gastrointestinal infections throughout the world. Biofilms trap these pathogens and can contaminate water supplies through subsequent release. Biofilm microbial assemblages were collected seasonally from three streams in eastern Pennsylvania and used to grow biofilms in laboratory microcosms. Daily oocyst counts in the influx and efflux flow allowed the calculation of daily oocyst retention in the biofilm. Following the removal of oocysts from the influx water, oocyst attachment to the biofilm declined to an equilibrium state within 5 days that was sustained for at least 25 days. Varying the oocyst loading rate for the system showed that biofilm retention could be saturated, suggesting that discrete binding sites determined the maximum number of oocysts retained. Oocyst retention varied seasonally but was consistent across all three sites; however, seasonal oocyst retention was not consistent across years at the same site. No correlation between oocyst attachment and any measured water quality parameter was found. However, oocyst retention was strongly correlated with biofilm surface roughness and roughness varied among seasons and across years. We hypothesize that biofilm roughness and oocyst retention are dependent on environmentally driven changes in the biofilm community rather than directly on water quality conditions. It is important to understand oocyst transport dynamics to reduce risks of human infection. Better understanding of factors controlling biofilm retention of oocysts should improve our understanding of oocyst transport at different scales.</jats:p>

Roles of ionic strength and biofilm roughness on adhesion kinetics of Escherichia coli onto groundwater biofilm grown on PVC surfaces

“…Our observation that both E. coli and CML particles had higher adhesion on biofilms with higher roughness is consistent with previous work on oocysts and E. coli adhesion to P. aeruginosa biofilms (Searcy et al, 2006; Wu et al, 2012), and on oocyst adhesion to biofilms collected from rivers (DiCesare et al, 2012). Roughness was also found to influence adhesion of colloidal particles to abiotic surfaces (Chen et al, 2010; Subramani and Hoek, 2010).…”

“…Biofilm roughness has been found to control deposition of Cryptosporidium oocysts and E. coli to Pseudomonas aeruginosa biofilms (Searcy et al, 2006; Wu et al, 2012). Roughness of mixed-species river biofilms was also found to control oocyst deposition (DiCesare et al, 2012). The first step of biofilm formation involving bacterial cell adhesion to surface has been studied in much more detail than adhesion of cells to mature biofilms.…”

Biofilms for Monitoring Presence of Microsporidia in Environmental Water

“…; Olapade and Leff ), altering surface roughness which impacts the retention of pathogens (Wolyniak DiCesare et al. ). The time frame after exposure and the efficiency for biofilms to capture and retain Microsporidia spores has yet to be clarified.…”

“…Pathogens, even when below detection limits, adhere to biofilms which then act as a reservoir and represent a potential source of water contamination (Koh et al 2013;Wolyniak et al 2009). However; biofilm biomass and community structure shift with season (Moss et al 2006;Olapade and Leff 2005), altering surface roughness which impacts the retention of pathogens (Wolyniak DiCesare et al 2012). The time frame after exposure and the efficiency for biofilms to capture and retain Microsporidia spores has yet to be clarified.…”

A New Pathogen Transmission Mechanism in the Ocean: The Case of Sea Otter Exposure to the Land-Parasite Toxoplasma gondii

“…The cysteine-rich proteins of T. gondii oocyst are related to those of the walls of another coccidian parasite, Cryptosporidium oocyst, [55]. Interestingly, the adhesion of Cryptosporidium oocysts to biofilms on man-made surfaces has been verified and the roughness of the biofilm has been strongly correlated with oocyst retention [56]–[58]. Giardia cysts, which are also covered with a polymeric matrix, have also been documented to attach to biofilms [59].…”