The history and geographic distribution of a KCNQ1 atrial fibrillation risk allele

The genetic architecture of atrial fibrillation (AF) encompasses low impact, common genetic variants and high impact, rare variants. Here, we characterize a high impact AF-susceptibility allele, KCNQ1 R231H, and describe its transcontinental geographic distribution and history. Induced pluripotent stem cell-derived cardiomyocytes procured from risk allele carriers exhibit abbreviated action potential duration, consistent with a gain-of-function effect. Using identity-by-descent (IBD) networks, we estimate the broad- and fine-scale population ancestry of risk allele carriers and their relatives. Analysis of ancestral migration routes reveals ancestors who inhabited Denmark in the 1700s, migrated to the Northeastern United States in the early 1800s, and traveled across the Midwest to arrive in Utah in the late 1800s. IBD/coalescent-based allele dating analysis reveals a relatively recent origin of the AF risk allele (~5000 years). Thus, our approach broadens the scope of study for disease susceptibility alleles to the context of human migration and ancestral origins.

Salinipeptins: Integrated Genomic and Chemical Approaches Reveal Unusual d-Amino Acid-Containing Ribosomally Synthesized and Post-Translationally Modified Peptides (RiPPs) from a Great Salt Lake Streptomyces sp

Analysis of the full genome of an environmentally unique, halotolerant Streptomyces sp. strain GSL-6C, isolated from the Great Salt Lake, revealed a gene cluster encoding the biosynthesis of the salinipeptins, d-amino-acid-containing members of the rare linaridin subfamily of ribosomally synthesized and post-translationally modified peptides (RiPPs). The sequence organization of the unmodified amino acid residues in salinipeptins A-D (1-4) were suggested by genome annotation, and subsequently, their sequence and post-translational modifications were defined using a range of spectroscopic techniques and chemical derivatization approaches. The salinipeptins are unprecedented linaridins bearing nine d-amino acids, which are uncommon in RiPP natural products and are the first reported in the linaridin subfamily. Whole genome mining of GSL-6C did not reveal any homologues of the reported genes responsible for amino acid epimerization in RiPPs, inferring new epimerases may be involved in the conversion of l- to d-amino acids. In addition, the N-oxide and dimethylimidazolidin-4-one moieties in salinipeptins B and C, which are modified from N, N-dimethylalanine, are unknown in bacterial peptides. The three-dimensional structure of salinipeptin A, possessing four loops generated by significant hydrogen bonding, was established on the basis of observed nuclear Overhauser effect (NOE) correlations. This study demonstrates that integration of genomic information early in chemical analysis significantly facilitates the discovery and structure characterization of novel microbial secondary metabolites.

Epidemiology and outcomes of Clostridium difficile infection in allogeneic hematopoietic cell and lung transplant recipients

BACKGROUND

Clostridium difficile infection (CDI) is a common complication of lung and allogeneic hematopoietic cell (HCT) transplant, but the epidemiology and outcomes of CDI after transplant are poorly described.

METHODS

We performed a prospective, multicenter study of CDI within 365 days post-allogeneic HCT or lung transplantation. Data were collected via patient interviews and medical chart review. Participants were followed weekly in the 12 weeks post-transplant and while hospitalized and contacted monthly up to 18 months post-transplantation.

RESULTS

Six sites participated in the study with 614 total participants; 4 enrolled allogeneic HCT (385 participants) and 5 enrolled lung transplant recipients (229 participants). One hundred and fifty CDI cases occurred within 1 year of transplantation; the incidence among lung transplant recipients was 13.1% and among allogeneic HCTs was 31.2%. Median time to CDI was significantly shorter among allogeneic HCT than lung transplant recipients (27 days vs 90 days; P = .037). CDI was associated with significantly higher mortality from 31 to 180 days post-index date among the allogeneic HCT recipients (Hazard ratio [HR] = 1.80; P = .007). There was a trend towards increased mortality among lung transplant recipients from 120 to 180 days post-index date (HR = 4.7, P = .09).

CONCLUSIONS

The epidemiology and outcomes of CDI vary by transplant population; surveillance for CDI should continue beyond the immediate post-transplant period.

Endemic fungal infections in solid organ and hematopoietic cell transplant recipients enrolled in the Transplant-Associated Infection Surveillance Network (TRANSNET)

BACKGROUND

Invasive fungal infections are a major cause of morbidity and mortality among solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients, but few data have been reported on the epidemiology of endemic fungal infections in these populations.

METHODS

Fifteen institutions belonging to the Transplant-Associated Infection Surveillance Network prospectively enrolled SOT and HCT recipients with histoplasmosis, blastomycosis, or coccidioidomycosis occurring between March 2001 and March 2006.

RESULTS

A total of 70 patients (64 SOT recipients and 6 HCT recipients) had infection with an endemic mycosis, including 52 with histoplasmosis, 9 with blastomycosis, and 9 with coccidioidomycosis. The 12-month cumulative incidence rate among SOT recipients for histoplasmosis was 0.102%. Occurrence of infection was bimodal; 28 (40%) infections occurred in the first 6 months post transplantation, and 24 (34%) occurred between 2 and 11 years post transplantation. Three patients were documented to have acquired infection from the donor organ. Seven SOT recipients with histoplasmosis and 3 with coccidioidomycosis died (16%); no HCT recipient died.

CONCLUSIONS

This 5-year multicenter prospective surveillance study found that endemic mycoses occur uncommonly in SOT and HCT recipients, and that the period at risk extends for years after transplantation.

Napyradiomycin derivatives, produced by a marine-derived actinomycete, illustrate cytotoxicity by induction of apoptosis

The microbial production, isolation, and structure elucidation of four new napyradiomycin congeners (1-4) is reported. The structures of these compounds, which are new additions to the marine-derived meroterpenoids, were defined by comprehensive spectroscopic analysis and by X-ray crystallography. Using fluorescence-activated cell sorting (FACS) analysis, napyradiomycins 1-4 were observed to induce apoptosis in the colon adenocarcinoma cell line HCT-116, indicating the possibility of a specific biochemical target for this class of cytotoxins.

Actinoranone, a cytotoxic meroterpenoid of unprecedented structure from a marine adapted Streptomyces sp

The isolation and structure elucidation of a new meroterpenoid, actinoranone (1), produced by a marine bacterium closely related to the genus Streptomyces is reported. Actinoranone is composed of an unprecedented dihydronaphthalenone polyketide linked to a bicyclic diterpenoid. The stereochemistry of 1 was defined by application of the advanced Mosher's method and by interpretation of spectroscopic data. Actinoranone (1) is significantly cytotoxic to HCT-116 human colon cancer cells with an LD50 = 2.0 μg/mL.

Anthracimycin, a potent anthrax antibiotic from a marine-derived actinomycete

Licensed to kill: A new antibiotic, anthracimycin (see scheme), produced by a marine-derived actinomycete in saline culture, shows significant activity toward Bacillus anthracis, the bacterial pathogen responsible for anthrax infections. Chlorination of anthracimycin gives a dichloro derivative that retains activity against Gram-positive bacteria, such as anthrax, but also shows activity against selected Gram-negative bacteria.

Structures and comparative characterization of biosynthetic gene clusters for cyanosporasides, enediyne-derived natural products from marine actinomycetes

Cyanosporasides are marine bacterial natural products containing a chlorinated cyclopenta[a]indene core of suspected enediyne polyketide biosynthetic origin. Herein, we report the isolation and characterization of novel cyanosporasides C-F (3-6) from the marine actinomycetes Salinispora pacifica CNS-143 and Streptomyces sp. CNT-179, highlighted by the unprecedented C-2' N-acetylcysteamine functionalized hexose group of 6. Cloning, sequencing, and mutagenesis of homologous ~50 kb cyanosporaside biosynthetic gene clusters from both bacteria afforded the first genetic evidence supporting cyanosporaside's enediyne, and thereby p-benzyne biradical, biosynthetic origin and revealed the molecular basis for nitrile and glycosyl functionalization. This study provides new opportunities for bioengineering of enediyne derivatives and expands the structural diversity afforded by enediyne gene clusters.

Isolation and Characterization of Actinoramides A-C, Highly Modified Peptides from a Marine Streptomyces sp

Reported herein is the isolation and structure elucidation of three highly modified peptides, actinoramides A-C (1-3), which are produced by a marine bacterium closely related to the genus Streptomyces. The planar structures of the actinoramides, which are composed of the unusual amino acids 2-amino-4-ureidobutanoic acid and 4-amino-3-hydroxy-2-methyl-5-phenylpentanoic acid, were assigned by chemical transformations and by interpretation of spectroscopic data, while the absolute configuration of these new peptides were defined by application of the advanced Marfey's and Mosher's methods.

Structure and biosynthesis of the marine streptomycete ansamycin ansalactam A and its distinctive branched chain polyketide extender unit

Reported is the structure and biosynthesis of ansalactam A, an ansamycin class polyketide produced by an unusual modification of the polyketide pathway. This new metabolite, produced by a marine sediment-derived bacterium of the genus Streptomyces , possesses a novel spiro γ-lactam moiety and a distinctive isobutyryl polyketide fragment observed for the first time in this class of natural products. The structure of ansalactam A was defined by spectroscopic methods including X-ray crystallographic analysis. Biosynthetic studies with stable isotopes further led to the discovery of a new, branched chain polyketide synthase extender unit derived from (E)-4-methyl-2-pentenoic acid for polyketide assembly observed for the first time in this class of natural products.

Structures, reactivities, and antibiotic properties of the marinopyrroles A-F

Cultivation of actinomycete strain CNQ-418, retrieved from a deep ocean sediment sample off the coast of La Jolla, CA, has provided marinopyrroles A-F. Sharing just 98% 16S rRNA gene sequence identity with S. sannurensis, the strain likely represents a new Streptomyces species. The metabolites contain an unusual 1,3'-bipyrrole core decorated with several chlorine and bromine substituents and possess marked antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). The congested N,C-biaryl bond establishes an axis of chirality that, for marinopyrroles A-E, is configurationally stable at room temperature. Moreover, the natural products are fashioned strictly in the M-configuration. The Paal-Knorr condensation was adapted for the synthesis of the 1,3'-bipyrrole core. Halogenation of this material with N-bromosuccinimide cleanly furnished the 4,4',5,5'-tetrahalogenated core that characterizes this class of marine-derived metabolites.

Fijiolides A and B, inhibitors of TNF-alpha-induced NFkappaB activation, from a marine-derived sediment bacterium of the genus Nocardiopsis

Fijiolide A, a potent inhibitor of TNF-alpha-induced NFkappaB activation, along with fijiolide B, were isolated from a marine-derived bacterium of the genus Nocardiopsis. The planar structures of fijiolides A (1) and B (2) were elucidated by interpretation of 2D NMR spectroscopic data, while the absolute configurations of these compounds were defined by interpretation of circular dichroism and 2D NMR data combined with application of the advanced Mosher's method. Fijiolides A and B are related to several recently isolated chloroaromatic compounds, which appear to be the Bergman cyclization products of enediyne precursors. Fijiolide A reduced TNF-alpha-induced NFkappaB activation by 70.3%, with an IC(50) value of 0.57 micro-M. Fijiolide B demonstrated less inhibition, only 46.5%, without dose dependence. The same pattern was also observed with quinone reductase (QR) activity: fijiolide A was found to induce quinone reductase-1 (QR1) with an induction ratio of 3.5 at a concentration of 20 microg/mL (28.4 microM). The concentration required to double the activity was 1.8 microM. Fijiolide B did not affect QR1 activity, indicating the importance of the nitrogen substitution pattern for biological activity. On the basis of these data, fijiolide A is viewed as a promising lead for more advanced anticancer testing.

Lodopyridone, a structurally unprecedented alkaloid from a marine actinomycete

Chemical examination of the secondary metabolites of a marine Saccharomonospora sp., isolated from marine sediments collected at the mouth of the La Jolla Submarine Canyon, yielded the unprecedented alkaloid lodopyridone (1). The low proton-to-carbon ratio of 1 precluded structure elucidation by NMR spectroscopic methods, thus the structure was defined by X-ray crystallography. Lodopyridone is cytotoxic to HCT-116 human colon cancer cells with IC(50) = 3.6 microM.

Saliniquinones A-F, New Members of the Highly Cytotoxic Anthraquinone-γ-Pyrones from the Marine Actinomycete Salinispora arenicola

Six new anthraquinone-γ-pyrones, saliniquinones A-F (1-6), which are related to metabolites of the pluramycin/altromycin class, were isolated from a fermentation broth of the marine actinomycete Salinispora arenicola (strain CNS-325). Their structures were determined by analysis of one- and two-dimensional NMR spectroscopic and high-resolution mass spectrometric data. The relative and absolute configurations of compounds 1-6 were determined by analysis of NOESY NMR spectroscopic data and by comparison of circular dichroism and optical rotation data with model compounds found in the literature. Saliniquinone A (1) exhibited potent inhibition of the human colon adenocarcinoma cell line (HCT-116) with an IC₅₀ of 9.9 × 10^-9 M. In the context of the biosynthetic diversity of S. arenicola, compounds 1-6 represent secondary metabolites that appear to be strain specific and thus occur outside of the core group of compounds commonly observed from this species.

Marinisporolides, polyene-polyol macrolides from a marine actinomycete of the new genus Marinispora

Two new polyene macrolides, marinisporolides A and B (1, 2), were isolated from the saline culture of the marine actinomycete, strain CNQ-140, identified as a member of the new marine genus Marinispora. The marinisporolides are 34-membered macrolides composed of a conjugated pentaene and several pairs of 1,3-dihydroxyl functionalities. Marinisporolide A (1) contains a bicyclic spiro-bis-tetrahydropyran ketal functionality, while marinisporolide B (2) is the corresponding hemiketal. The structures of these new compounds were assigned by combined spectral and chemical methods including extensive 2D NMR experiments and correlations of (13)C NMR data with Kishi's Universal NMR Database. Chemical modifications, including methanolysis, acetonide formation, and application of the modified Mosher method, provided the full stereostructures of these molecules. Three additional macrolides, marinisporolides C-E (3-5), which are olefin geometric isomers of marinisporolide A (1), were also isolated and their structures defined. Under room light, marinisporolides A and B readily photoisomerize to C-E indicating that they are most likely produced by photochemical conversion during the cultivation or isolation procedures. Although polyenes, marinisporolides A (1) and B (2) showed weak to no antifungal activity against Candida albicans.

Outcomes of antifungal prophylaxis in high-risk liver transplant recipients

Antifungal prophylaxis for liver transplant recipients (LTRs) is common among patients considered at high risk of infection, but optimal prophylaxis duration and drug has not been defined. This study aimed to assess the effects of 14 days of antifungal therapy prophylaxis in reducing proven invasive fungal infections (IFI) in high-risk subjects. Eligible subjects who met 2 or more risk criteria were randomized 1:1 to the treatment arms (liposomal amphotericin B or fluconazole) and were followed for 100 days post transplantation for evidence of IFI. The study was designed to enroll 300 subjects, but was closed early for insufficient enrollment. A total of 71 subjects were enrolled and randomized. Two-thirds of subjects completed 14 days of study therapy. Ten subjects developed proven or probable IFI with Candida species (9 subjects) and Cryptococcus neoformans (1 subject); rates were similar in the 2 treatment arms. Eleven subjects died, but no death was attributed to study drug or IFI. In summary, high-risk LTRs tolerated antifungal prophylaxis well, and rates of IFI were lower than previously reported in untreated high-risk LTRs.

Marineosins A and B, cytotoxic spiroaminals from a marine-derived actinomycete

Two novel spiroaminals, marineosins A and B (1, 2), containing two pyrrole functionalities, were isolated from cultures of a marine sediment-derived actinomycete related to the genus Streptomyces. The marineosins, which appear to be derived from unknown modifications of prodigiosin-like pigment pathways, showed significant inhibition of human colon carcinoma (HCT-116) in an in vitro assay (IC50 = 0.5 microM for marineosin A) and selective activities in diverse cancer cell types.

Salinipyrones and pacificanones, mixed-precursor polyketides from the marine actinomycete Salinispora pacifica

Chemical examination of a phylogenetically unique strain of the obligate marine actinomycete Salinispora pacifica led to the discovery of four new polyketides, salinipyrones A and B ( 1, 2) and pacificanones A and B ( 3, 4). These compounds appear to be derived from a mixed-precursor polyketide biosynthesis involving acetate, propionate, and butyrate building blocks. Spectral analysis, employing NMR, IR, UV, and CD methods and chemical derivatization, was used to assign the structures and absolute configurations of these new metabolites. Salinipyrones A and B displayed exactly opposite CD spectra, indicating their pseudoenantiomeric relationship. This relationship was shown to be a consequence of the geometric isomerization of one double bond. The phenomenon of polyketide module skipping is proposed to explain the unusual biosynthesis of the salinipyrones and the pacificanones.

Multicenter retrospective development and validation of a clinical prediction rule for nosocomial invasive candidiasis in the intensive care setting

The study presented here was performed in order to create a rule that identifies subjects at high risk for invasive candidiasis in the intensive care setting. Retrospective review and statistical modelling were carried out on 2,890 patients who stayed at least 4 days in nine hospitals in the USA and Brazil; the overall incidence of invasive candidiasis in this group was 3% (88 cases). The best performing rule was as follows: Any systemic antibiotic (days 1-3) OR presence of a central venous catheter (days 1-3) AND at least TWO of the following-total parenteral nutrition (days 1-3), any dialysis (days 1-3), any major surgery (days -7-0), pancreatitis (days -7-0), any use of steroids (days -7-3), or use of other immunosuppressive agents (days -7-0). The rate of invasive candidiasis among patients meeting the rule was 9.9%, capturing 34% of cases in the units, with the following performance: relative risk 4.36, sensitivity 0.34, specificity 0.90, positive predictive value 0.01, and negative predictive value 0.97. The rule may identify patients at high risk of invasive candidiasis.

Induced production of emericellamides A and B from the marine-derived fungus Emericella sp. in competing co-culture

Induction of the production of emericellamides A and B (1, 2), by the marine-derived fungus Emericella sp., was observed during co-culture with the marine actinomycete Salinispora arenicola. The planar structures of these new cyclic depsipeptides, which incorporate 3-hydroxy-2,4-dimethyldecanoic acid and 3-hydroxy-2,4,6-trimethyldodecanoic acid, were assigned by combined chemical and spectral methods. The absolute configurations of the amino acids, and those of the chiral centers on the side chain, were established by application of the Marfey's method, by J-based configuration analysis, and by application of the modified Mosher method. Emericellamides A and B show modest antibacterial activities against methicillin-resistant Staphylococcus aureus with MIC values of 3.8 and 6.0 microM, respectively.

Thalassospiramides A and B, immunosuppressive peptides from the marine bacterium Thalassospira sp

[structure: see text] Two new cyclic peptides, thalassospiramides A and B (1 and 2), were isolated from a new member of the marine alpha-proteobacterium Thalassospira. The thalassospiramides, the structures of which were assigned by combined spectral and chemical methods, bear unusual gamma-amino acids and show immunosuppressive activity in an interleukin-5 production inhibition assay (IC50 = 5 muM for thalassospiramide B).

Piperazimycins: cytotoxic hexadepsipeptides from a marine-derived bacterium of the genus Streptomyces

Three potent cancer cell cytotoxins, piperazimycins A-C (1-3), have been isolated from the fermentation broth of a Streptomyces sp., cultivated from marine sediments near the island of Guam. The structures of these cyclic hexadepsipeptides were assigned by a combination of spectral, chemical, and crystallographic methods. The piperazimycins are composed of rare amino acids, including hydroxyacetic acid, alpha-methylserine, gamma-hydroxypiperazic acid, and gamma-chloropiperazic acid. The novel amino acid residues 2-amino-8-methyl-4,6-nonadienoic acid and 2-amino-8-methyl-4,6-decadienoic acid were found as components of piperazimycins A and C, respectively. When screened in the National Cancer Institute's 60 cancer cell line panel, piperazimycin A exhibited potent in vitro cytotoxicity toward multiple tumor cell lines with a mean GI50 of 100 nM.

Cyanosporasides A and B, chloro- and cyano-cyclopenta[a]indene glycosides from the marine actinomycete "Salinispora pacifica"

[structure: see text] Two structurally novel cyclopenta[a]indene glycosides, cyanosporasides A and B (1 and 2) have been isolated from the culture broth of a new species of the obligate marine actinomycete genus Salinispora. The structures and absolute stereochemistries of these compounds were determined by spectral and chemical methods. The cyanosporasides possess a new 3-keto-pyranohexose sugar as well as a cyano- and chloro-substituted cyclopenta[a]indene ring system. The cyanosporasides are proposed to be cyclization products of an enediyne precursor.

Daryamides A-C, weakly cytotoxic polyketides from a marine-derived actinomycete of the genus Streptomyces strain CNQ-085

In the course of our continuing search for new antitumor-antibiotics from marine-derived actinomycete bacteria, four new cytotoxic compounds, designated as daryamides A (1), B (2), and C (3) and (2E,4E)-7-methylocta-2,4-dienoic acid amide (4), were isolated from the culture broth of a marine-derived Streptomyces strain CNQ-085. The structures of these new compounds were assigned by detailed interpretation of spectroscopic data. The relative configuration of 1 was determined by comprehensive NMR analysis, while the absolute configuration of 1 was determined as 4S,5R using the modified Mosher method. The daryamides show weak to moderate cytotoxic activity against the human colon carcinoma cell line HCT-116 and very weak antifungal activities against Candida albicans.

Cardiobacterium hominis endocarditis: Two cases and a review of the literature

Cardiobacterium hominis, a member of the HACEK group (Haemophilus parainfluenzae, Haemophilus aphrophilus, and Haemophilus paraphrophilus, Actinobacillus actinomycetemcomitans, C. hominis, Eikenella corrodens, and Kingella species), is a rare cause of endocarditis. There are 61 reported cases of C. hominis infective endocarditis in the English-language literature, 15 of which involved prosthetic valve endocarditis. There is one reported case of C. hominis after upper endoscopy and none reported after colonoscopy. Presented here are two cases of C. hominis prosthetic valve endocarditis following colonoscopy and a review of the microbiological and clinical features of C. hominis endocarditis. Patients with C. hominis infection have a long duration of symptoms preceding diagnosis (138+/-128 days). The most common symptoms were fever (74%), fatigue/malaise (53%), weight loss/anorexia (40%), night sweats (24%), and arthralgia/myalgia (21%). The most common risk factors were pre-existing cardiac disease (61%), the presence of a prosthetic valve (28%), and history of rheumatic fever (20%). Of the 61 cases reviewed here, the aortic valve was infected in 24 (39%) and the mitral valve in 19 (31%) patients. The average duration of blood culture incubation before growth was detected was 6.3 days (range, 2-21 days). Complications were congestive heart failure (40%), central nervous system (CNS) emboli (21%), arrhythmia (16%), and mycotic aneurysm (9%). C. hominis is almost always susceptible to beta-lactam antibiotics. Ceftriaxone is recommended by the recently published American Heart Association guidelines. The prognosis of C. hominis native valve and prosthetic valve endocarditis is favorable. The cure rate among 60 patients reviewed was 93% (56/60). For prosthetic valve endocarditis, the cure rate was 16/17 (94%). Valve replacement was required in 27 (45%) cases.

Bohemamines from a marine-derived Streptomyces sp

Investigation of the culture extracts of a marine-derived Streptomyces sp. led to the isolation of three new bohemamine-type pyrrolizidine alkaloids, bohemamine B (1), bohemamine C (2), and 5-chlorobohemamine C (3). The structures were elucidated using NMR methods, and the relative stereochemistry was determined using double-pulsed-field-gradient spin echo (DPFGSE) NOE studies.

Sporolides A and B: structurally unprecedented halogenated macrolides from the marine actinomycete Salinispora tropica

[structure: see text] Analysis of the fermentation broth of a strain of the marine actinomycete Salinispora tropica has led to the isolation of two unprecedented macrolides, sporolides A (1) and B (2). The structures and absolute stereochemistries of both metabolites were elucidated using a combination of NMR spectroscopy and X-ray crystallography.

Marinomycins A-D, antitumor-antibiotics of a new structure class from a marine actinomycete of the recently discovered genus "marinispora"

Four antitumor-antibiotics of a new structure class, the marinomycins A-D (1-4), were isolated from the saline culture of a new group of marine actinomycetes, for which we have proposed the name "Marinispora". The structures of the marinomycins, which are unusual macrodiolides composed of dimeric 2-hydroxy-6-alkenyl-benzoic acid lactones with conjugated tetraene-pentahydroxy polyketide chains, were assigned by combined spectral and chemical methods. In room light, marinomycin A slowly isomerizes to its geometrical isomers marinomycins B and C. Marinomycins A-D show significant antimicrobial activities against drug resistant bacterial pathogens and demonstrate impressive and selective cancer cell cytotoxicities against six of the eight melanoma cell lines in the National Cancer Institute's 60 cell line panel. The discovery of these new compounds from a new, chemically rich genus further documents that marine actinomycetes are a significant resource for drug discovery.

Actinofuranones A and B, polyketides from a marine-derived bacterium related to the genus streptomyces (actinomycetales)

Two new polyketides, actinofuranones A (1) and B (2), were isolated from the culture extract of a marine-derived Streptomyces strain designated CNQ766. The structures of 1 and 2 were elucidated by interpretation of NMR and other spectroscopic data and by chemical derivatization. The relative stereochemistries of these new molecules were assigned on the basis of analysis of NOE data and vicinal (1)H-(1)H coupling constants, while the absolute configurations of the asymmetric centers were determined using the modified Mosher's method.

Invasive fungal infections in low-risk liver transplant recipients: a multi-center prospective observational study

Prevention of invasive fungal infections (IFIs) in orthotopic liver transplant (OLT) recipients utilizing postoperative systemic antifungal prophylaxis, typically with fluconazole, is justified among those at high risk for IFI. Use of postoperative antifungal prophylaxis for low-risk OLT recipients is widely practiced but not universally accepted nor supported by data. We conducted a prospective observational study among 200 OLT recipients who were at low risk for IFI and did not receive postoperative antifungal prophylaxis. Patients were considered low risk if they had </=1 of the following conditions: choledochojejunostomy anastomosis; retransplantation; intra-operative administration of >/=units of 40 blood products or return to the operating room for intra-abdominal bleeding; return to the operating room for anastomotic leak or vascular insufficiency; preoperative serum creatinine of >/=2 mg/dL; and perioperative Candida colonization. Patients were followed 100 d post-transplantation for evidence of IFI. Of 193 eligible patients, 7 (4%) developed an IFI. Three (2%) IFIs were due to Candida spp. and potentially preventable by standard fluconazole prophylaxis. Three patients developed invasive aspergillosis; one developed late onset disseminated cryptococcosis. Liver transplant recipients at low risk for IFI can be identified utilizing pre-determined criteria, and post-transplantation antifungal prophylaxis can be routinely withheld in these patients.

Libertellenones A-D: induction of cytotoxic diterpenoid biosynthesis by marine microbial competition

The induction of biosynthesis of four new diterpenoids was observed following the addition of a marine alpha-proteobacterium to an established culture of the marine-derived fungus Libertella sp. The fungal strain and the marine bacterium, cultured alone, do not produce diterpenoid metabolites. The induced diterpenoids, libertellenones A-D, are cross-conjugated ketones of the pimarane class. The libertellenones show varying levels of cytotoxicity against the HCT-116 human adenocarcinoma cell line with libertellenone D being the most potent (IC50 = 0.76 microM).

Salinispora arenicola gen. nov., sp. nov. and Salinispora tropica sp. nov., obligate marine actinomycetes belonging to the family Micromonosporaceae

A taxonomic study was carried out to clarify the taxonomy of representatives of a group of marine actinomycetes previously designated MAR 1 and considered to belong to the family Micromonosporaceae. The organisms had phenotypic properties consistent with their assignment to this taxon. The strains formed a distinct taxon in the 16S rRNA Micromonosporaceae gene tree and shared a range of phenotypic properties that distinguished them from members of all of the genera with validly published names classified in this family. The name proposed for this novel taxon is Salinispora gen. nov. The genus contains two species recognized using a range of genotypic and phenotypic criteria, including comparative 16S-23S rRNA gene spacer region and DNA-DNA relatedness data. The names proposed for these taxa are Salinispora arenicola sp. nov., the type species, and Salinispora tropica sp. nov.; the type strains of these novel species have been deposited in service culture collections as strain CNH-643(T) (=ATCC BAA-917(T)=DSM 44819(T)) and strain CNB-440(T) (=ATCC BAA-916(T)=DSM 44818(T)), respectively.

New Cytotoxic Salinosporamides from the Marine ActinomyceteSalinisporatropica

An extensive study of the secondary metabolites produced by the obligate marine actinomycete Salinispora tropica (strain CNB-392), the producing microbe of the potent proteasome inhibitor salinosporamide A (1), has led to the isolation of seven related gamma-lactams. The most important of these compounds were salinosporamide B (3), which is the deschloro-analogue of 1, and salinosporamide C (4), which is a decarboxylated pyrrole analogue. New SAR data for all eight compounds, derived from extensive testing against the human colon carcinoma HCT-116 and the 60-cell-line panel at the NCI, indicate that the chloroethyl moiety plays a major role in the enhanced activity of 1.

A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults

BACKGROUND

The incidence and severity of herpes zoster and postherpetic neuralgia increase with age in association with a progressive decline in cell-mediated immunity to varicella-zoster virus (VZV). We tested the hypothesis that vaccination against VZV would decrease the incidence, severity, or both of herpes zoster and postherpetic neuralgia among older adults.

METHODS

We enrolled 38,546 adults 60 years of age or older in a randomized, double-blind, placebo-controlled trial of an investigational live attenuated Oka/Merck VZV vaccine ("zoster vaccine"). Herpes zoster was diagnosed according to clinical and laboratory criteria. The pain and discomfort associated with herpes zoster were measured repeatedly for six months. The primary end point was the burden of illness due to herpes zoster, a measure affected by the incidence, severity, and duration of the associated pain and discomfort. The secondary end point was the incidence of postherpetic neuralgia.

RESULTS

More than 95 percent of the subjects continued in the study to its completion, with a median of 3.12 years of surveillance for herpes zoster. A total of 957 confirmed cases of herpes zoster (315 among vaccine recipients and 642 among placebo recipients) and 107 cases of postherpetic neuralgia (27 among vaccine recipients and 80 among placebo recipients) were included in the efficacy analysis. The use of the zoster vaccine reduced the burden of illness due to herpes zoster by 61.1 percent (P<0.001), reduced the incidence of postherpetic neuralgia by 66.5 percent (P<0.001), and reduced the incidence of herpes zoster by 51.3 percent (P<0.001). Reactions at the injection site were more frequent among vaccine recipients but were generally mild.

CONCLUSIONS

The zoster vaccine markedly reduced morbidity from herpes zoster and postherpetic neuralgia among older adults.

Disseminated Scedosporium apiospermum infection in a previously healthy woman with HELLP syndrome

A previously healthy 33-year-old female died of disseminated infection with Scedosporium apiospermum in association with Hemolysis, Elevated Liver enzymes, and Low Platelets (HELLP) syndrome following the delivery of twins. Her postpartum course was complicated by multisystem organ failure managed with extracorporeal membrane oxygenation (ECMO). She also developed bowel and left lower extremity ischemia requiring surgical resection. Blood cultures yielded S. apiospermum, and histologic findings revealed in vivo adventitious sporulation, an unusual occurrence with this pathogen. Autopsy showed extensive fungal infection of brain, lungs, thyroid, heart, and kidneys.

Halovirs A-E, new antiviral agents from a marine-derived fungus of the genus Scytalidium

Marine micro-organisms represent an under explored resource for the discovery of novel antiviral agents. Here, we describe a series of peptides designated halovirs A-E (1-5) that are produced during the saline fermentation of a marine-derived fungus of the genus Scytalidium. These lipophilic, linear peptides are potent in vitro inhibitors of the herpes simplex viruses 1 and 2. Evidence is presented that the halovirs directly inactivate herpes viruses, a mechanism of action that could be applicable in the prevention of HSV transmission. The total structures of these new compounds were established by a combination of spectral and chemical techniques. Salient structural features of the halovir hexapeptides include a nitrogen terminus acylated by myristic (C14) or lauric (C12) acid, an unusual Aib-Hyp dipeptide segment, and a carboxyl terminus reduced to a primary alcohol. A qualitative analysis of the secondary structures of these molecules using variable temperature NMR experiments and NOE analyses is also reported.

Halovirs A-E, new antiviral agents from a marine-derived fungus of the genus Scytalidium

Marine micro-organisms represent an under explored resource for the discovery of novel antiviral agents. Here, we describe a series of peptides designated halovirs A-E (1-5) that are produced during the saline fermentation of a marine-derived fungus of the genus Scytalidium. These lipophilic, linear peptides are potent in vitro inhibitors of the herpes simplex viruses 1 and 2. Evidence is presented that the halovirs directly inactivate herpes viruses, a mechanism of action that could be applicable in the prevention of HSV transmission. The total structures of these new compounds were established by a combination of spectral and chemical techniques. Salient structural features of the halovir hexapeptides include a nitrogen terminus acylated by myristic (C14) or lauric (C12) acid, an unusual Aib-Hyp dipeptide segment, and a carboxyl terminus reduced to a primary alcohol. A qualitative analysis of the secondary structures of these molecules using variable temperature NMR experiments and NOE analyses is also reported.

Widespread and persistent populations of a major new marine actinomycete taxon in ocean sediments

A major taxon of obligate marine bacteria within the order Actinomycetales has been discovered from ocean sediments. Populations of these bacteria (designated MAR 1) are persistent and widespread, spanning at least three distinct ocean systems. In this study, 212 actinomycete isolates possessing MAR 1 morphologies were examined and all but two displayed an obligate requirement of seawater for growth. Forty-five of these isolates, representing all observed seawater-requiring morphotypes, were partially sequenced and found to share characteristic small-subunit rRNA signature nucleotides between positions 207 and 468 (Escherichia coli numbering). Phylogenetic characterization of seven representative isolates based on almost complete sequences of genes encoding 16S rRNA (16S ribosomal DNA) yielded a monophyletic clade within the family Micromonosporaceae and suggests novelty at the genus level. This is the first evidence for the existence of widespread populations of obligate marine actinomycetes. Organic extracts from cultured members of this new group exhibit remarkable biological activity, suggesting that they represent a prolific resource for biotechnological applications.

Salmonella prosthetic joint septic arthritis

We describe a case of Salmonella enteritidis infection of a prosthetic knee joint that was cured with ceftriaxone therapy for 6 weeks and replacement of the tibial component of the prosthesis. Eleven other cases of salmonella prosthetic joint infection have been reported in the English-language literature. Five infections occurred within 20 days of prosthesis placement, and seven occurred several months to years later; ten of 12 infections involved hip prostheses. Nine of 12 patients who had prosthesis removal were cured of the infection. Two of the three patients with retention of the prosthesis required long-term suppressive antibiotic therapy.

The impact of culture isolation of Aspergillus species: a hospital-based survey of aspergillosis

The term "aspergillosis" comprises several categories of infection: invasive aspergillosis; chronic necrotizing aspergillosis; aspergilloma, or fungus ball; and allergic bronchopulmonary aspergillosis. In 24 medical centers, we examined the impact of a culture positive for Aspergillus species on the diagnosis, risk factors, management, and outcome associated with these diseases. Most Aspergillus culture isolates from nonsterile body sites do not represent disease. However, for high-risk patients, such as allogeneic bone marrow transplant recipients (60%), persons with hematologic cancer (50%), and those with signs of neutropenia (60%) or malnutrition (30%), a positive culture result is associated with invasive disease. When such risk factors as human immunodeficiency virus infection (20%), solid-organ transplantation (20%), corticosteroid use (20%), or an underlying pulmonary disease (10%) are associated with a positive culture result, clinical judgment and better diagnostic tests are necessary. The management of invasive aspergillosis remains suboptimal: only 38% of patients are alive 3 months after diagnosis. Chronic necrotizing aspergillosis, aspergilloma, and allergic bronchopulmonary aspergillosis have variable management strategies and better short-term outcomes.

Case report. Recurrence of increased intracranial pressure with antiretroviral therapy in an AIDS patient with cryptococcal meningitis

We present the case of an AIDS patient with cryptococcal meningitis who, after an excellent clinical and mycological response to antifungal therapy, developed an exacerbation of signs and symptoms, including elevated intracranial pressure and an increase in cerebrospinal fluid cryptococcal antigen and white blood cells, following the initiation of highly active antiretroviral therapy (HAART). Cultures yielded no growth and the patient responded to repeated lumbar punctures without changing or intensifying antifungal therapy. To our knowledge, this is the first report of symptomatic elevated intracranial pressure occurring during HAART-related immune recovery in a patient with cryptococcal meningitis. Exacerbation of symptoms does not necessarily reflect mycological failure that requires a change in antifungal therapy, but may relate to acutely increased intracranial pressure that will respond to simple measures, such as repeated lumbar punctures.

Trends in species causing fungaemia in a tertiary care medical centre over 12 years

Trends in the species of yeast causing fungaemia over a 12-year period at a large tertiary care medical centre were reviewed. A total of 966 unique episodes of fungaemia occurred in 898 patients. There was an overall trend toward fewer fungaemic episodes due to Candida albicans and more due to Candida glabrata and Candida parapsilosis. However, C. albicans remained the predominant species causing fungaemia, and the proportion due to other species varied from year to year. Candida glabrata was disproportionately isolated from older adults, whereas C. parapsilosis was common among neonates and infants. The trends of increasing isolation of C. glabrata and decreasing isolation of C. albicans were associated with increasing usage of fluconazole, but changes in the proportion of fungaemias due to other species appeared to have no association with fluconazole usage.

Treatment of systemic fungal infections in older patients: achieving optimal outcomes

Systemic fungal infections are an increasing problem in older adults. For several of the endemic mycoses, this increase is the result of increased travel and leisure activities in areas endemic for these fungi. Immunosuppressive agents, care in an intensive care unit, and invasive devices all contribute to infection with opportunistic fungi. Treatment of systemic fungal infections is usually with an azole or amphotericin B. The preferred regimen depends on the specific fungal infection, the site and the severity of the infection, the state of immunosuppression of the patient and the possible toxicities of each drug for a specific patient. In older adults, drug-drug interactions between the azoles and drugs commonly prescribed for older persons may lead to serious toxicity, and absorption of itraconazole can be problematic. Amphotericin B is associated with significant nephrotoxicity, especially in older adults with pre-existing renal disease, and infusion-related adverse effects. Newer lipid formulations of amphotericin B can obviate some of these toxicities, but their role in the treatment of systemic fungal infections in older adults has not yet been clarified.