Tracking Inhibitory Alterations during Interstrain <i>Clostridium difficile</i> Interactions by Monitoring Cell Envelope Capacitance

Global threats arising from the increasing use of antibiotics coupled with the high recurrence rates of <i>Clostridium difficil</i>e (<i>C. difficile</i>) infections (CDI) after standard antibiotic treatments highlight the role of commensal probiotic microorganisms, including nontoxigenic <i>C. difficile</i> (NTCD) strains in preventing CDI due to highly toxigenic <i>C. difficile</i> (HTCD) strains. However, optimization of the inhibitory permutations due to commensal interactions in the microbiota requires probes capable of monitoring phenotypic alterations to <i>C. difficile</i> cells. Herein, by monitoring the field screening behavior of the <i>C. difficile</i> cell envelope with respect to cytoplasmic polarization, we demonstrate that inhibition of the host-cell colonization ability of HTCD due to the S-layer alterations occurring after its co-culture with NTCD can be quantitatively tracked on the basis of the capacitance of the cell envelope of co-cultured HTCD. Furthermore, it is shown that effective inhibition requires the dynamic contact of HTCD cells with freshly secreted extracellular factors from NTCD because contact with the cell-free supernatant causes only mild inhibition. We envision a rapid method for screening the inhibitory permutations to arrest <i>C. difficile</i> colonization by routinely probing alterations in the HTCD dielectrophoretic frequency response due to variations in the capacitance of its cell envelope

Tracking Inhibitory Alterations during Interstrain <i>Clostridium difficile</i> Interactions by Monitoring Cell Envelope Capacitance

Global threats arising from the increasing use of antibiotics coupled with the high recurrence rates of <i>Clostridium difficil</i>e (<i>C. difficile</i>) infections (CDI) after standard antibiotic treatments highlight the role of commensal probiotic microorganisms, including nontoxigenic <i>C. difficile</i> (NTCD) strains in preventing CDI due to highly toxigenic <i>C. difficile</i> (HTCD) strains. However, optimization of the inhibitory permutations due to commensal interactions in the microbiota requires probes capable of monitoring phenotypic alterations to <i>C. difficile</i> cells. Herein, by monitoring the field screening behavior of the <i>C. difficile</i> cell envelope with respect to cytoplasmic polarization, we demonstrate that inhibition of the host-cell colonization ability of HTCD due to the S-layer alterations occurring after its co-culture with NTCD can be quantitatively tracked on the basis of the capacitance of the cell envelope of co-cultured HTCD. Furthermore, it is shown that effective inhibition requires the dynamic contact of HTCD cells with freshly secreted extracellular factors from NTCD because contact with the cell-free supernatant causes only mild inhibition. We envision a rapid method for screening the inhibitory permutations to arrest <i>C. difficile</i> colonization by routinely probing alterations in the HTCD dielectrophoretic frequency response due to variations in the capacitance of its cell envelope

Tracking Inhibitory Alterations during Interstrain <i>Clostridium difficile</i> Interactions by Monitoring Cell Envelope Capacitance

Global threats arising from the increasing use of antibiotics coupled with the high recurrence rates of <i>Clostridium difficil</i>e (<i>C. difficile</i>) infections (CDI) after standard antibiotic treatments highlight the role of commensal probiotic microorganisms, including nontoxigenic <i>C. difficile</i> (NTCD) strains in preventing CDI due to highly toxigenic <i>C. difficile</i> (HTCD) strains. However, optimization of the inhibitory permutations due to commensal interactions in the microbiota requires probes capable of monitoring phenotypic alterations to <i>C. difficile</i> cells. Herein, by monitoring the field screening behavior of the <i>C. difficile</i> cell envelope with respect to cytoplasmic polarization, we demonstrate that inhibition of the host-cell colonization ability of HTCD due to the S-layer alterations occurring after its co-culture with NTCD can be quantitatively tracked on the basis of the capacitance of the cell envelope of co-cultured HTCD. Furthermore, it is shown that effective inhibition requires the dynamic contact of HTCD cells with freshly secreted extracellular factors from NTCD because contact with the cell-free supernatant causes only mild inhibition. We envision a rapid method for screening the inhibitory permutations to arrest <i>C. difficile</i> colonization by routinely probing alterations in the HTCD dielectrophoretic frequency response due to variations in the capacitance of its cell envelope

Dielectrophoretic Monitoring and Interstrain Separation of Intact <i>Clostridium difficile</i> Based on Their S(Surface)-Layers

<i>Clostridium difficile</i> (<i>C. difficile</i>) infection (CDI) rates have exhibited a steady rise worldwide over the last two decades and the infection poses a global threat due to the emergence of antibiotic resistant strains. Interstrain antagonistic interactions across the host microbiome form an important strategy for controlling the emergence of CDI. The current diagnosis method for CDI, based on immunoassays for toxins produced by pathogenic <i>C. difficile</i> strains, is limited by false negatives due to rapid toxin degradation. Furthermore, simultaneous monitoring of nontoxigenic <i>C. difficile</i> strains is not possible, due to absence of these toxins, thereby limiting its application toward the control of CDI through optimizing antagonistic interstrain interactions. Herein, we demonstrate that morphological differences within the cell wall of particular <i>C. difficile</i> strains with differing S-layer proteins can induce systematic variations in their electrophysiology, due alterations in cell wall capacitance. As a result, dielectrophoretic frequency analysis can enable the independent fingerprinting and label-free separation of intact microbials of each strain type from mixed <i>C. difficile</i> samples. The sensitivity of this contact-less electrophysiological method is benchmarked against the immunoassay and microbial growth rate methods for detecting alterations within both, toxigenic and nontoxigenic <i>C. difficile</i> strains after vancomycin treatment. This microfluidic diagnostic platform can assist in the development of therapies for arresting clostridial infections by enabling the isolation of individual strains, optimization of antibiotic treatments and the monitoring of microbiomes

Point-of-Use Removal of <i>Cryptosporidium parvum</i> from Water: Independent Effects of Disinfection by Silver Nanoparticles and Silver Ions and by Physical Filtration in Ceramic Porous Media

Ceramic water filters (CWFs) impregnated with silver nanoparticles are a means of household-level water treatment. CWFs remove/deactivate microbial pathogens by employing two mechanisms: metallic disinfection and physical filtration. Herein we report on the independent effects of silver salt and nanoparticles on <i>Cryptosporidium parvum</i> and the removal of <i>C. parvum</i> by physical filtration in porous ceramic filter media. Using a murine (mouse) model, we observed that treatment of oocysts with silver nitrate and proteinate-capped silver nanoparticles resulted in decreased infection relative to untreated oocysts. Microscopy and excystation experiments were conducted to support the disinfection investigation. Heat and proteinate-capped silver-nanoparticle treatment of oocysts resulted in morphological modifications and decreased excystation rates of sporozoites. Subsequently, disk-shaped ceramic filters were produced to investigate the transport of <i>C. parvum</i>. Two factors were varied: sawdust size and clay-to-sawdust ratio. Five disks were prepared with combinations of 10, 16, and 20 mesh sawdust and sawdust percentage that ranged from 9 to 11%. <i>C. parvum</i> removal efficiencies ranged from 1.5 log (96.4%) to 2.1 log (99.2%). The 16-mesh/10% sawdust had the greatest mean reduction of 2.1-log (99.2%), though there was no statistically significant difference in removal efficiency. Based on our findings, physical filtration and silver nanoparticle disinfection likely contribute to treatment of <i>C. parvum</i> for silver impregnated ceramic water filters, although the contribution of physical filtration is likely greater than silver disinfection