The proposed diverse mechanistic modes of action for antimicrobial peptides in microbial cells.

<p>(A) Disruption of cell membrane integrity: (1) random insertion into the membrane, (2) alignment of hydrophobic sequences, and (3) removal of membrane sections and formation of pores. (B) Inhibition of DNA synthesis. (C) Blocking of RNA synthesis. (D) Inhibition of enzymes necessary for linking of cell wall structural proteins. (E) Inhibition of ribosomal function and protein synthesis. (F) Blocking of chaperone proteins necessary for proper folding of proteins. (G) Targeting of mitochondria: (1) inhibition of cellular respiration and induction of ROS formation and (2) disruption of mitochondrial cell membrane integrity and efflux of ATP and NADH.</p

Protein models representing the structural differences of the four classes of antimicrobial peptides.

<p>Antimicrobial peptides can be grouped into four major classes based on their secondary structures, including the (A) α-helical peptides, (B) peptides composed of a series of β-sheets, (C) peptides that adopt unconventional structures, such as extended helices, and (D) peptides that assemble into loops. All structures were obtained freely from the RCSB Protein Data Bank (PDB) (<a href="http://www.pdb.org/" target="_blank">http://www.pdb.org/</a>) and have been referenced according to their Digital Object Identifier (DOI) <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1001067#ppat.1001067-Berman1" target="_blank">[23]</a>. Additional information for each AMP may be obtained by consulting the RCSB PDB and cross-referencing the DOI.</p

Working model of the immunopathogenesis of <i>C. albicans</i> vaginitis.

<p>(<b>A</b>) Yeast forms of <i>C. albicans</i> asymptomatically colonize the vaginal epithelium despite the presence of numerous pattern recognition receptors (PRR) on the epithelial surface. (<b>B</b>) <i>C. albicans</i> begins to undergo the yeast-to-hypha switch under morphogenesis-inducing conditions (increases in estrogen, elevated vaginal pH, and microbiota disruption). Augmented recognition by PRRs, increased hyphal biomass, and expression of hypha-associated virulence factors elicits inflammatory signaling (S100A8/9 alarmins and proinflammatory cytokines) in the vaginal epithelium, resulting in initial migration of PMNs from the lamina propria (L.P.) to the vaginal lumen. (<b>C</b>) Failure to adequately reduce immunopathological triggers results in the continued expression of innate immune effectors by the vaginal epithelium. These initial signals, coupled with secondary amplification of immune effectors by recruited PMNs, contribute to symptomatic infection and characteristic immunopathology.</p

Polymicrobial regrowth after treatment with OS 1.

<p>Regrowth of mono- and polymicrobial biofilms on silicone disks after treatment with optimized lock solution. Monomicrobial (CA, SA) and polymicrobial (CA+SA) biofilms of <i>C</i>. <i>albicans</i> and <i>S</i>. <i>aureus</i> were challenged with drug free (DF, closed circles) or optimized solution (OS 1, 20% ethanol, 800 μg/mL doxycycline, and 0.015625 μg/mL micafungin, open circles) prepared in sterile growth medium for 24 hours. Immediately following lock solution treatment, disks were briefly sonicated and cultured in selective liquid medium for 24 hours. Serial dilutions were plated onto selective medium to quantify microbial regrowth. Horizontal line in dataset represents the median. Data is cumulative of four independent experiments performed in triplicate. *, P ≤ 0.05, ** P ≤ 0.01, *** P ≤ 0.001 using a Kruskal-Wallis one-way ANOVA and Dunn’s multiple comparisons post-test.</p

Mature <i>C</i>. <i>albicans</i> biofilm regrowth after 24 hour drug challenge.

<p>Combination solutions did not prevent the regrowth of mature biofilms on silicone. Following 24 hour drug challenge, biofilms were sonicated and incubated at 30°C for an additional 24 hours then plated solid media to quantify regrowth. Untreated and drug treated groups were compared using two-way ANOVA followed by Tukey post analysis. * indicates p value of < 0.05</p

<i>C</i>. <i>albicans</i> SC5314 colony regrowth after 24 hour drug challenge.

<p>All combination solutions were highly effective in preventing the regrowth of forming biofilms on silicone. Following 24 hour drug challenge, forming biofilms were sonicated and incubated at 30°C for an additional 24 hours then plated on solid media to quantify regrowth. The untreated control was compared to the drug treated groups using one-way ANOVA. * indicates p value of < 0.05</p

Pinellia tripartita Schott

原著和名: オホハンゲ科名: サトイモ科 = Araceae採集地: 高知県 横倉山中腹 (上峠) (土佐 横倉山中腹 (上峠))採集日: 1981/8/27採集者: 萩庭丈壽整理番号: JH033814国立科学博物館整理番号: TNS-VS-98381

An Optimized Lock Solution Containing Micafungin, Ethanol and Doxycycline Inhibits <i>Candida albicans</i> and Mixed <i>C</i>. <i>albicans – Staphyloccoccus aureus</i> Biofilms

<div><p><i>Candida albicans</i> is a major cause of catheter-related bloodstream infections and is associated with high morbidity and mortality. Due to the propensity of <i>C</i>. <i>albicans</i> to form drug-resistant biofilms, the current standard of care includes catheter removal; however, reinsertion may be technically challenging or risky. Prolonged exposure of an antifungal lock solution within the catheter in conjunction with systemic therapy has been experimentally attempted for catheter salvage. Previously, we demonstrated excellent <i>in vitro</i> activity of micafungin, ethanol, and high-dose doxycycline as single agents for prevention and treatment of <i>C</i>. <i>albicans</i> biofilms. Thus, we sought to investigate optimal combinations of micafungin, ethanol, and/or doxycycline as a lock solution. We performed two- and three-drug checkerboard assays to determine the <i>in vitro</i> activity of pairwise or three agents in combination for prevention or treatment of <i>C</i>. <i>albicans</i> biofilms. Optimal lock solutions were tested for activity against <i>C</i>. <i>albicans</i> clinical isolates, reference strains and polymicrobial <i>C</i>. <i>albicans-S</i>. <i>aureus</i> biofilms. A solution containing 20% (v/v) ethanol, 0.01565 μg/mL micafungin, and 800 μg/mL doxycycline demonstrated a reduction of 98% metabolic activity and no fungal regrowth when used to prevent fungal biofilm formation; however there was no advantage over 20% ethanol alone. This solution was also successful in inhibiting the regrowth of <i>C</i>. <i>albicans</i> from mature polymicrobial biofilms, although it was not fully bactericidal. Solutions containing 5% ethanol with low concentrations of micafungin and doxycycline demonstrated synergistic activity when used to prevent monomicrobial <i>C</i>. <i>albicans</i> biofilm formation. A combined solution of micafungin, ethanol and doxycycline is highly effective for the prevention of <i>C</i>. <i>albicans</i> biofilm formation but did not demonstrate an advantage over 20% ethanol alone in these studies.</p></div

Prevention of <i>C</i>. <i>albicans</i> SC5314 biofilm formation on silicone disks.

<p>Potential lock solutions are highly effective in preventing the formation of <i>C</i>. <i>albicans</i> biofilms on silicone. Planktonic <i>C</i>. <i>albicans</i> cells were incubated on silicone for 24 hours at 37°C with potential lock solution candidates. Metabolic activity was measured using XTT reduction and untreated vs drug treated groups were compared using a one-way ANOVA. * <i>indicates p value of < 0</i>.<i>05</i></p

Treatment of mature SC5314 biofilms on silicone disks.

<p>Potential lock solutions significantly reduced metabolic activity of mature <i>C</i>. <i>albicans</i> biofilms. Biofilms were incubated on silicone for 24 hour at 37°C with potential lock solutions. Metabolic activity was measured using XTT reduction. Untreated and drug treated groups were compared using two-way ANOVA followed by Tukey post analysis. * <i>indicates p value of < 0</i>.<i>05</i></p