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Microbiology: Current Research 2017 | Volume 1, Issue 2
Joint Conference
GLOBAL APPLIED MICROBIOLOGY CONFERENCE
MICROBIAL & BIOCHEMICAL RESEARCH AND TECHNOLOGIES October 18-19, 2017
Toronto, Canada
International Congress on &
Kinetic microplate assay reveals lethal and sub-lethal behavior of antimicrobials immobilized on solid
substrates
Steven Arcidiacono
US Army Soldier Natick Research Development and Engineering Center, USA
Statement of the Problem: Immobilization of antimicrobials
onto surfaces is of great interest, although characterization of
activity can be problematic. Traditional assays are designed
for determining solution based antimicrobial activity and is
incompatible with solid substrates.
Methodology & Theoretical Orientation: A kinetic microplate
method was developed to determine theminimumbactericidal
concentration (MBC) of the immobilized antimicrobial
peptides SMAP and Cecropin P1 through a combination and
modification of traditional solution assays, overcoming the
difficulties of working with a solid substrate. The microplate-
based kinetic assay was used to measure various peptide dose
and time-dependent activity at multiple concentrations; viable
plate counts were used to determine bactericidal activity and
correlated to the kinetic assay results.
Findings: Immobilized peptide activity against both Gram-
positive and Gram-negative bacteria has been demonstrated,
including Acinetobacter baumannii, Bacillus anthracis sterne
and Staphylococcus aureus, and correlated to viable plate count
results. Compared to peptides in solution, a combination of
increased concentration and longer exposure timewas required
for activity. Immobilized peptide potency was cell–dependent;
however, the peptides exhibited activity for all organisms in
a dose-dependent manner, reaching a critical concentration
that resulted in complete inhibition. The role of immobilized
peptide orientation relative to the solid substrate revealed that
orientation is critical to activity.
Conclusion&Significance: Thisassaysuccessfullydetermined
activity on magnetic beads and planar glass substrates;
other substrates such as antimicrobial textiles could also be
characterized with this technique. Furthermore, the method
yields information regarding sub-lethal concentrations not
realized in the traditional assays. This kinetic microplate
assay is also useful for testing antimicrobial formulations and
reveals both synergistic and antagonistic interactions against
clinical isolates and biothreat agents..
Speaker Biography
Steven Arcidiacono has an MS in Microbiology, with significant contributions in
the research areas of anaerobic fermentation, antimicrobials, and biopolymer
fermentation/fiber spinning. His primary focuses encompass exploratory research
and development studies in the following specific areas: 1) colonic fermentation for
biotransformation of nutritional and polyphenolic compounds; 2) skin microorganism
interaction when in co-culture; and 3) discovery of novel antimicrobials to combat
multidrug resistant bacteria and fungi. His prior experience/programs include
antimicrobial peptides for detection and microbial protection and aqueous spinning of
biopolymers (naturally-derived crystallin proteins and recombinant spider silk). He is
Author/Coauthor of >30 peer-reviewed manuscripts, book chapters, proceedings and
conference articles (cited >1500 times), numerous presentations, and an inventor on
two issued US patents and two patent applications.
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