Antimicrobial performance of two preoperative skin preparation solutions containing iodine and isopropyl alcohol.

BACKGROUND: Healthcare-associated infections (HAIs) are a persistent clinical challenge caused primarily by bacteria on the skin. Proper utilization of optimized antiseptic skin preparation solutions helps reduce the prevalence and impact of HAIs by decreasing patient skin microorganisms preoperatively. The purpose of this study was to evaluate the efficacy of 2 antimicrobial solutions containing iodine and isopropyl alcohol (IPA): Povidone iodine (PVP-I) with IPA (ie, PVP-I+IPA, PurPrep) and Iodine Povacrylex+IPA (DuraPrep). METHODS: The antimicrobial activity of the test solutions was evaluated in vitro by determinations of minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) against 1105 diverse microbial isolates and a time-kill assay to evaluate efficacy against 120 strains of Gram-positive and Gram-negative bacteria and yeasts. Peel tests were performed between skin samples treated with test solutions and representative drape/dressing materials to determine effects of test solutions on the biomechanical adhesion properties. Finally, an Institutional Review Board (IRB)-approved, randomized, controlled, single-center, partially blinded in vivo study was performed to assess the immediate and persistent antimicrobial activity of the test solutions on the abdomen and groin. RESULTS: Both PVP-I+IPA and Iodine Povacrylex+IPA solutions demonstrated broad-spectrum antimicrobial activity with MIC and MBC at less than 1% of the full-strength concentration of each product against a wide variety of microorganisms. In the time-kill tests, both solutions were able to successfully reduce all microbial populations by 99.99% (ie, 4 log10) at the contact times of 30 seconds, 2 minutes and 10 minutes. The 2 solutions showed relatively similar adhesion results when tested with 3 representative operating room materials. Both PVP-I+IPA and Iodine Povacrylex+IPA met the expected Food and Drug Administration (FDA) efficacy requirements at 10 minutes and 6 hours post-treatment for both anatomic sites (ie, groin, and abdomen) in the clinical study, with no safety issues or adverse events. CONCLUSIONS: Analysis of the in vitro antimicrobial activity, biomechanical adhesive strength, and in vivo efficacy of PVP-I+IPA demonstrated similar results compared to Iodine Povacrylex+IPA. Both products were efficacious at reducing or eliminating a wide range of clinically-relevant microorganisms in lab-based and clinical settings, supporting their use as antiseptic skin preparation solutions to reduce bacteria on the skin that can cause infection.

Depsides isolated from the Sri Lankan lichen Parmotrema sp. exhibit selective Plk1 inhibitory activity.

CONTEXT: Mitotic kinase enzymes regulate critical stages of mitosis and are amenable to pharmacological inhibition. Since natural products have been a rich source of antimitotic inhibitors, we postulated that natural products would also provide effective inhibitors of mitotic kinases. OBJECTIVE: To explore unique marine and terrestrial natural product sources for new anticancer drug leads, we screened our natural product extract library for polo-like kinase-1 (Plk1) kinase inhibitors. MATERIALS AND METHODS: Extracts of the lichen Parmotrema sp. (Parmeliaceae) exhibited in vitro inhibitory activity. Bioassay-guided fractionation of the Parmotrema sp. extract led to the isolation of depside inhibitors. RESULTS: A new depside 1 has been isolated from the Sri Lankan lichen Parmotrema sp. along with the known metabolites 2 (ß-collatolic acid) and 3 (ß-alectoronic acid). The structure of depside 1 was elucidated by spectroscopic analysis. The three depsides 1-3 exhibited moderate inhibition of purified recombinant Plk1 kinase with IC50 of 2.8, 0.7, and 1.7 µM, respectively, at 1 µM ATP. Inhibitory activity was also observed at high concentrations of ATP, suggesting the potential for activity in a cellular environment. The depsides were also tested against a panel of 23 other recombinant kinases and were found to possess up to 30-fold selectivity toward Plk1. DISCUSSION AND CONCLUSION: These data suggest that the depsides 1-3 may serve as core structures that can be further explored as potential inhibitors of Plk1 and other kinases.

Fermentative production of self-toxic fungal secondary metabolites.

Fungi are well known for their vast diversity of secondary metabolites that include many life-saving drugs and highly toxic mycotoxins. In general, fungal cultures producing such metabolites are immune to their toxic effects. However, some are known to produce self-toxic compounds that can pose production optimization challenges if the metabolites are needed in large amounts for chemical modification. One such culture, LV-2841, was identified as the lead for one of our exploratory projects. This culture was found to be a slow grower that produced trace amounts of a known metabolite, cercosporamide, under the standard flask fermentation conditions, and extensive medium optimization studies failed to yield higher titers. Poor growth of the culture in liquid media was attributed to the self-toxicity of cercosporamide to the producing organism, and the minimum inhibitory concentration (MIC) of cercosporamide was estimated to be in the range of 8-16 microg/ml. Fermentations carried out in media containing Diaion HP20 resin afforded significantly higher titers of the desired compound. While several examples of resin-based fermentations of soil streptomyces have been published, this approach has rarely been used for fungal fermentations. Over a 100-fold increase in the production titer of cercosporamide, a self-toxic secondary metabolite, was achieved by supplementing the production medium with a commercially available neutral adsorbent resin.

The lecanindoles, nonsteroidal progestins from the terrestrial fungus Verticillium lecanii 6144.

Four new indolosesquiterpenes, lecanindoles A-D (1-4), were isolated from fermentations of the terrestrial fungus Verticillium lecanii 6144. The structures of compounds 1-4 were elucidated from analysis of spectroscopic data. Compound 2 was reduced to give 4 and its isomer 5. Compound 4 was found to be a potent and selective progesterone receptor agonist with an EC50 of 1.1 +/- 0.4 nM in a cell-based luciferase reporter assay.

Norselic acids A-E, highly oxidized anti-infective steroids that deter mesograzer predation, from the Antarctic sponge Crella sp.

Five new steroids, norselic acids A-E (1-5), were isolated from the sponge Crella sp. collected in Antarctica. The planar structures of the norselic acids were established by extensive NMR spectroscopy and mass spectrometry studies, and the configuration of norselic acid A (1) was elucidated by X-ray crystallography. Norselic acid A displays antibiotic activity against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-sensitive S. aureus (MSSA), vancomycin-resistant Enterococcus faecium (VRE), and Candida albicans and reduces consumption of food pellets by sympatric mesograzers. Compounds 1-5 are also active against the Leishmania parasite at low micromolar levels.

Investigating the biosynthetic origin of the nitro group in pyrrolomycins.

Feasible modes of introducing the nitro group into pyrrolomycin antibiotics were investigated based on incorporation of (15)N-labeled arginine and proline into dioxapyrrolomycin, produced by the actinomycete culture LL-F42248. Biosynthesis of nitrated pyrrolomycins was unaffected by the presence of nitric oxide synthase (NOS) inhibitors. The culture was able to grow in nitrogen-free (minimal) media and produce nitrated secondary metabolites. These results indicate that LL-F42248 is capable of fixing nitrogen.

Cytoskyrins and cytosporones produced by Cytospora sp. CR200: taxonomy, fermentation and biological activities.

In screening endophytic fungi from Costa Rica for bioactivity, fungal culture CR200, isolated from a buttonwood tree, was found to contain compounds that initiate DNA damage in a test strain of E. coli (Biochemical Induction Assay, BIA) and inhibit growth of Gram-positive bacteria, including antibiotic-resistant strains. Two new bisanthraquinones (cytoskyrins A and B) and five new related octaketides (cytosporones A-E) were isolated from fermentation broths of this fungus. Cytoskyrin A exhibited potent in-vitro antibacterial (MICs against Gram-positive bacteria, 0.03-0.25 microg/mL) and DNA-damaging activities (10 ng/spot), whereas cytoskyrin B was inactive in these assays. Among the cytosporones, only D and E exhibited Gram-positive activity, but they were inactive in the BIA. Mechanistically, cytoskyrin A specifically inhibited DNA synthesis in E. coli imp at its MIC; however, it also moderately inhibited protein synthesis at 2x its MIC. Cytoskyrin A exhibited poor cytotoxicity against tumor cell lines (IC50>5 microg/mL) compared to known antitumor agents. The nuclear ribosomal internal transcribed spacer region of CR200 was found to share highest similarity (94-96%) with Cytospora spp. Micro- and macroscopic morphological observations of the conidia and conidiomata, respectively, also suggested this fungus to be a Cytospora sp.

Lichenicolins A and B, new bisnaphthopyrones from an unidentified lichenicolous fungus, strain LL-RB0668.

Lichenicolous fungus LL-RB0668 was isolated from a processed lichen thallus on a modified Lilly-Barnett solid medium. Two new bisnaphthopyrone compounds, lichenicolins A (1) and B (2), were isolated from the culture broth of this organism fermented on a rice-based solid medium. These results demonstrate that lichen-associated fungi potentially are a good resource for new bioactive natural products for current screening programs.

Isolation of three new naturally occurring compounds from the culture of Micromonospora sp. P1068.

Bioassay guided isolation of an antibacterial extract prepared from the fermentation broth of a Micromonospora sp. P1068 led to the isolation of eight compounds identified as (3R) 3,4',7-trihydroxy-isoflavanone (1), 3-hydroxydehydrodaidzein, daidzein (2), 3-methyl-1H-indole-2-carboxylic acid (3), 1H-indole-3-carboxaldehyde (4), 3-(p-hydroxyphenyl)-N-methylpropionamide, N-methylphloretamide (5), phenyl acetic acid (6), 2-hydroxy phenyl acetic acid (7) and 4-hydroxy-5-methoxy-benzoic acid (8). Compounds 1 and 5 were found to be novel chemical entities while 3 was isolated from a natural source for the first time. All compounds were evaluated for their antimicrobial activities against a panel of clinically significant microorganisms. Compound 4 was active against Staphylococcus aureus (MIC, 32 microg/ml), Enterococcus faecium (MIC, 32 microg/ml) and Escherichia coli (MIC, 64 microg/ml).

Novel alpha-pyrones produced by a marine Pseudomonas sp. F92S91: taxonomy and biological activities.

Inhibitors of the enzymes involved in fatty acid biosynthesis (FAB) have been reported as antibacterial agents. These include thiolactomycin, cerulenin, triclosan, diazoborine, naphthyridinones, aminopyridines and pyridoindoles. Our search for new FAB inhibitors, using a lacZ reporter cell-based screen, led to several confirmed hits. Culture F92S91, later identified as a Pseudomonas sp. based on 16S profiling, was found to produce two alpha-pyrones (I and II) and three high molecular weight peptides. The pyrones were unstable under acidic conditions, and they were rearranged into a furanone derivative (III). Of these compounds, pyrone I was the most active with MICs (microg/ml) against B. subtilis (1 to approximately 2), MRSA (2 to approximately 4), M. catarrhalis (4) and VRE (2 to approximately 64). Effects on macromolecular synthesis and membrane functions were tested in B. subtilis. Pyrone I nonspecifically inhibited incorporation of radiolabeled precursors into DNA, RNA and protein within 5 minutes of drug exposure, similar to that of triclosan. Both compounds also inhibited the cellular uptake of these precursors. Cerulenin did not have an effect until 30 minutes of drug treatment. Pyrone I and triclosan were membrane-active (BacLight test); however, pyrone I (at < or = 128 microg/ml concentration) was not hemolytic to human RBCs in contrast to triclosan, which was hemolytic at 16 microg/ml. These data suggest that pyrone-I, unlike triclosan, selectively affects bacterial membrane function.

Constituents of antibacterial extract of Caesalpinia paraguariensis Burk.

The Argentinean legume Caesalpinia paraguariensis Burk. (Fabaceae) was selected for further fractionation work based on the strong antimicrobial activity of its CH2Cl2-MeOH (1:1 v/v) extract against a host of clinically significant microorganisms, including antibiotic resistant strains. 1D and 2D NMR enabled the identification of the novel benzoxecin derivative caesalpinol along with the known compounds bilobetin, stigma-5-en-3-O-beta-6'-stearoylglucopyranoside, stigma-5-en-3-beta-6'-palmitoylglucopyranoside, stigma-5-en-3-beta-glucopyranoside, oleanolic acid, 3-O-(E)-hydroxycinnamoyl oleanolic acid, betulinic acid, 3-O-(E)-hydroxycinnamoyl betulinic acid, and lupeol from the active fractions. Oleanolic acid was found active against Bacillus subtilis and both methicillin-sensitive and -resistant Staphylococcus aureus with MICs of 8 (17.5 microM), 8 and 64 (140 microM) microg/ml, respectively. The rest of the compounds, however, did not show activity.

Pseudopyronines A and B, alpha-pyrones produced by a marine Pseudomonas sp. F92S91, and evidence for the conversion of 4-hydroxy-alpha-pyrone to 3-furanone.

In our search for inhibitors of bacterial fatty acid biosynthesis, two new alpha-pyrones, pseudopyronines A (1) and B (2), were isolated from a marine Pseudomonas sp. F92S91. The naturally occurring alpha-pyrones appeared to be unstable, evidenced by the conversion of pseudopyronine B into an oxidation product, 3-furanone (3). Structural elucidations were made by spectroscopic analyses including 2D-NMR data.

Antibacterial diterpenes from Calceolaria pinifolia.

Two new isopimaranes, 19-methylmalonyloxy-ent-isopimara-8(9),15-diene (5) and 19-malonyloxy-ent-isopimara-8(9),15-diene (6), were isolated using bioassay-guided fractionation of the CH(2)Cl(2)-MeOH (1:1) extract of the aerial part of Calceolaria pinifolia along with eight other diterpenes (1-4, 7-10) and two triterpenes (11, 12). All compounds were assayed against Staphylococcus aureus (SA), methicillin-resistant S. aureus (MRSA), Bacillus subtilis (BS), and Escherichia coli (EC). 4-Epi-dehydroabietinol (2) and ent-isopimara-9(11),15-diene-19-ol (8) were found to be active against MRSA with MIC values of 8 and 2 microgram/mL, respectively. Mechanistic studies of 8 in BS suggested rapid and nonspecific inhibition of uptake and incorporation of radiolabeled precursors into DNA, RNA, and protein consistent with membrane-damaging effects in bacteria. Compound 8 did not afford protection against an acute infection with SA in mice.

A novel antibacterial iridoid and triterpene from Caiophora coronata.

Bioassay-guided fractionation of the antibacterial CH(2)Cl(2)-MeOH extract obtained from the aerial parts of the Argentinean plant Caiophora coronata led to the isolation of a new triterpene, 1beta,3beta-dihydroxyurs-12-en-27-oic acid, 1, and a new iridoid, 1alpha-methoxy-6alpha,10-dihydroxyisoepiiridomyrmecin (caiophoraenin), 2, along with the known iridoid isoboonein 3. Their structures were established by spectroscopic techniques (1D and 2D NMR, HRFABMS, FTIR). The MIC values of isolated compounds were determined against methicillin-sensitive (MSSA) and -resistant (MRSA) strains of Staphylococcus aureus, Bacillus subtilis (BS), vancomycin-resistant Enterococcus faecium (VREF), Escherichia coli (EC), E. coli imp (ECimp), and Candida albicans (CA). Compound 1 was found active against BS, MSSA, MRSA, VREF, and ECimp with MIC values of 2, 4, 4, 4, and 16 microg/mL, respectively.

New antimicrobial cycloartane triterpenes from Acalypha communis.

Three new cycloartane-type triterpenes, 16 alpha-hydroxymollic (1), 15 alpha-hydroxymollic (2), and 7 beta,16 beta-dihydroxy-1,23-dideoxyjessic acids (3), were isolated from the aerial parts of Acalypha communis. The structures of the novel triterpenes were determined by spectroscopic methods as well as chemical derivatization. These compounds were tested for their antimicrobial activity against Gram-positive and -negative bacteria. Compounds 1-3 exhibited moderate antimicrobial activity (MIC 8, 32, 8 microg/mL, respectively) against vancomycin-resistant enterococci. In addition, compound 1 was found to be active against methicillin-resistant staphylococci. In contrast, compounds 1-3 were poorly active against Gram-negative bacteria. Compound 3 was tested in an in vivo model; it did not provide protection to mice infected with Staphylococcus aureus.

Chemical investigation of predator-deterred macroalgae from the Antarctic peninsula.

Chemical investigation of five Antarctic macroalgae whose tissues and crude extracts displayed ecologically relevant feeding deterrence in field bioassays was performed. Eleven compounds were characterized from the three red algae studied, of which four (1-3 and 9) were previously unreported, and four compounds were found from two brown algae, two (12 and 14) of which are new natural products. Several of these pure compounds have been individually investigated in ecological and/or pharmacological bioassays.