Current Topics

2014 ICAAC

Sometimes BafflingTickborne Microbial IllnessesContinue To Emerge

Shannon Weiman

Genomic analyses are enabling investi-gators to uncover novel tickborne bac-terial diseases that were previously ofunknown origin or were misdiagnosedas Lyme, which is caused by Borreliaburgdorferi. These flu-like illnesses in-clude symptoms such as fever, head-ache, and fatigue, but are transmittedby specifıc species of ticks, typically inparticular geographic regions, accord-ing to several researchers who spokeduring the symposium “Tick-borne In-fectious Diseases” at the 2014 Inter-science Conference on AntimicrobialAgents and Chemotherapy, held inWashington, D.C., last September.

A particularly gruesome tickborneillness, called scalp eschar and necklymphadenopathy after tick bite,emerged recently in Europe, accordingto Arantza Portillo of the Center forBiomedical Research in Rioja, Spain.Infected individuals characteristicallyexperience necrotic skin lesions andswollen lymph nodes but lack the tell-tale rash of other rickettsioses or ofLyme disease, she says. Nearly all le-sions appear on the head of affectedindividuals because the tick vector,Dermacentor marginatus, climbs to 1.5meters above the ground to await itsprey. Nearly all these ticks in Europecarry one or more of the causative spe-cies Rickettsia rioja, R. raoultii, and R.slovaca. “These pathogens have proba-bly been circulating in Europe for along time,” she says. A comparable dis-ease, caused by Rickettsia spp. 364D,was recently reported in California.

Other gram-negative rickettsia spe-cies cause ehrlichiosis, another type oftick-borne disease. A new variety ofehrlichia was identifıed in 2009, and isfound only in Minnesota and Wiscon-sin, according to Bobbi Pritt of MayoClinic in Rochester, Minn. That speciesis transmitted by Ixodes scapularisticks, in contrast to other types of ehrli-chia that are transmitted by Ambly-omma americanum ticks, she says.

A Lyme-like disease, detected in thesouthern United States during the late1980s, is called Southern-tick associ-ated rash illness (STARI). Character-ized by a more uniform rash than thebulls-eye rash that often occurs at theoutset of Lyme disease, these earlycases fırst appeared outside the geo-graphic range of the primary tick vec-tor of Lyme, I. scapularis. The Lymespirochete “could not be isolated fromhuman cases from the region, and the

tick associated with the illness was A.americanum, which is not a vectorfor B. burgdorferi,” says AdrianaMarques of the National Institute forAllergy and Infectious Diseases inBethesda, Md. While the causal agentfor STARI remains unknown, this ill-ness appears to be more prevalentthan Lyme in some areas, she warns.“A. americanum are the most abun-dant biting ticks in the southernUnited States, and their range ex-tends all the way up to Maine.”

A tickborne agent, Borrelia myamo-toi, found fırst in Japan in 1995, subse-quently was found in several regionsacross Europe and North America, ac-cording to John Branda of Massachu-setts General Hospital in Boston. ThisBorrelia species causes a severe acuteillness that often requires infected indi-viduals to be hospitalized, he says. It istransmitted by Ixodes ticks, and its

Amblyomma americanum tick. This wide-ranging tick rarely carries Borrelia burgdorferi, thecausative agent of Lyme disease, but is a vector for Southern-tick associated rash illness (STARI),the causative agent of which is unknown (CDC photo.)

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prevalence may be about 10% that ofLyme disease.Shannon Weiman is a freelance writer inSan Francisco, Calif.

2014 ICAAC

Host Gene Changes AffectHow Bacteria Colonize ThoseHosts

Shannon WeimanSingle-nucleotide polymorphisms (SNPs)in genes encoding immune receptors,signaling molecules, and other mole-cules not classically associated with im-mune responses can affect how wellsome bacterial pathogens or commen-sal species colonize individual hosts,according to several researchers whospoke during the 2014 InterscienceConference on Antimicrobials andChemotherapy (ICAAC), held inWashington, D.C., last September. Ex-ploring these associations, researchershope to reveal mechanisms underlyingdisease pathology and other host-mi-crobe interactions.

Some individuals are particularlysusceptible to invasive pneumococcaldisease (IPD), according to AnnaSangil Betriu of the Hospital Universi-tari Mutua Terrassa in Catalonya,Spain. Some 43 SNPs in 10 immunegenes are linked to rare cases occur-ring in otherwise healthy individuals,“which may explain their susceptibil-ity,” she says. Most prominent are mi-nor alleles in the interleukin-1 receptor1, which mediates innate inflammatoryresponses, and in two inhibitors of nu-clear factor kB that regulate signalingof innate and adaptive responses. “Ifconfırmed, these fındings may help usto better understand the genesis of theillness, and to identify people at risk,”she says.

A single SNP in the gene for theleptin receptor (LEPR) appears toconfer a threefold-greater suscepti-bility to infections by Clostridium dif-fıcile, according to Rajat Madan of theUniversity of Virginia in Charlottes-

ville. This same Q233R mutation inLEPR is also linked to susceptibilityto Entamoeba histolytica infections,he notes.

Leptin, better known for its role inappetite and obesity, also influences gutintegrity, microbiome composition, andinflammatory responses, Madan says.“Leptin is pro-inflammatory and aug-ments the host defense during infections,presumably by enhancing immune re-sponses.” The mutation impairs LEPRactivation of signal transducer and acti-vator of transcription 3 signaling, reduc-ing mucosal chemokine production andneutrophil recruitment in mice, thusrendering them less able to clear C. diffı-cile from the gut, he says. These fındings“demonstrate a connection between me-tabolism and immunity.”

In other cases SNPs in host genesmay influence the gut microbiota,thereby indirectly affecting suscepti-bility to pathogens or the likelihoodof developing still other types of dis-eases, according to Jose A. Oteo of theCentro de Investigacion Biomédicade La Rioja in Rioja, Spain. “Changesin gut microbiota composition maybe responsible for a plethora of pa-thologies, including inflammatorybowel diseases, colon cancer, andobesity,” he says. For example, aSNP in the adrenomedullin gene(rs4910118), which decreases circu-lating levels of adrenomedullin, apeptide with antimicrobial proper-ties, may dictate gut colonization byspecifıc bacterial species. In femalemice, knocking out this gene reducesthe abundance of Bacteroidales andClostridiales, while increasing En-terobacteriales, a bacterial order sug-gested to be implicated in high-fat-,diet-induced obesity, he says. He andhis collaborators plan to examinewhether humans with this SNP ex-hibit similar changes in microbiotaand how this may influence their like-lihood of developing various diseas-es. “This SNP is linked to cancer andhigh blood pressure,” he notes.

2014 ICAAC

Several Strategies inSearch for AgentsTo Treat MERS-CoV

Shannon WeimanResearchers are seeking to identify anddevelop agents that target the MiddleEast respiratory syndrome coronavirus

MINITOPIC

White House ImposesAnother Voluntary Haltto Gain-of-FunctionResearch

The White House Office of Scienceand Technology Policy and Depart-ment of Health and Human Servicesannounced in October that it wassuspending funding for “gain-of-function” research, pending a “delib-erative process” to assess its risksand benefits. Such gain-of-functionstudies typically try deliberately toenhance the pathogenicity or trans-missibility of infectious agents suchas the influenza and MERS viruses.The White House asked the NationalScience Advisory Board for Biosecu-rity (NSABB), which is a federal advi-sory board operating under the aus-pices of the National Institutes ofHealth, and the National ResearchCouncil of the National Academiesto conduct this policy review. NSABBmembers were scheduled to conferlate in November before issuing astatement on these issues. While thistwo-part review is under way, thegovernment is asking researchers“to voluntarily pause their research,whether federally funded or not,while risks and benefits are beingreassessed.” An earlier voluntarymoratorium on such research involv-ing the H5N1 influenza virus endedin 2013 when several sets of re-searchers announced they would re-sume their investigations.

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(MERS-CoV), which kills about 30% ofindividuals that it infects. Promisingleads are arising from target-baseddrug development approaches and alsofrom efforts to repurpose drugs thatalready are approved for treating otherconditions, according to several re-searchers who summarized recentprogress during the 2014 InterscienceConference on Antimicrobial Agentsand Chemotherapy, held in Washing-ton, D.C., last September.

Several inhibitors of viral helicase,spike protein, and RNA synthesis en-zymes look promising when tested invitro against MERS-CoV, according toJasper Chan of the University of HongKong in China. Several of them are alsoactive against the closely related severeacute respiratory syndrome coronavi-rus (SARS-CoV). Additionally, mono-clonal antibodies and plasma from pa-tients recovering from MERS-CoVinfections neutralize that virus, he says,

noting that convalescent plasma is be-ing evaluated in clinical trials in theMiddle East.

The papain-like protease (PLpro) ofMERS-CoV, which is essential for itsreplication, is another target for candi-date drugs, according to Hyuan Leeand Michael Johnson of the Universityof Illinois, Chicago. Although many in-hibitors of the SARS-CoV PLproproved to be ineffective against theMERS-CoV PLpro, she and her col-league Hao Lei recently identifıed aninhibitor of both viral enzymes. “High-throughput screening of 25,000 com-pounds produced a dual inhibitor thatacts as an allosteric inhibitor againstSARS-CoV PLpro and also acts as acompetitive inhibitor against MERS-CoV PLpro,” says Lee. The compoundalso works in synergy with other leadinhibitors against SARS-CoV PLpro.

However, this target-based ap-proach is painstaking, and it could take

years before any of these promising vi-ral inhibitors are approved as drugs,Chan cautions. An alternate and per-haps faster strategy involves testingcurrently approved antiviral agents, inhopes of repurposing some of them totreat MERS-CoV infections. Broad-spectrum agents, such as type-I inter-ferons, or those used to treat SARSsuch as ribavirin and lopinavir appearpromising, he says. Moreover, interfer-ons synergize with ribavirin in vitroand in rhesus macaques, he says.

Yet another strategy casts a widernet and seeks to repurpose other typesof drugs. For example, several cancerdrugs, antidepressants, and hormonereceptor modulators show anti-MERSactivity, according to Lisa Hensley ofthe National Institute of Allergy andInfectious Diseases (NIAID) inBethesda, Md. She says that ChrisColeman of the University of Marylandin Baltimore, Lisa Johansen of Zalicusin Cambridge, Mass., and their collab-orators identifıed 6 SARS-CoV-spe-cifıc inhibitors, 33 MERS-CoV-specifıcinhibitors, and 27 inhibitors of bothviruses while screening a set of 290drugs that were approved by the Foodand Drug Administration (FDA) forother purposes. For example, chlor-promazine HCl, a neurotransmitterantagonist used to treat patients withschizophrenia, synergizes with variousother drugs, Hensley says. Chan fındsthat mycophenolic acid, an immuno-suppressant used to prevent rejectionof transplanted organs, has anti-MERS-CoV activity, particularly incombination with Interferon �1b.

Between 2012 when MERS-CoVemerged and July 2014, this virus in-fected at least 837 people across 20countries with a fatality rate of about30%, according the World HealthOrganization. SARS-CoV, whichemerged in 2003, had a higher infectiv-ity rate and caused about 8,000 casesworldwide that year and several dozenthe next, but has not reappeared duringthe past decade. Its fatality rate wasabout 10%.

MINITOPIC

Progress in Developing Disparate Vaccines

Regulatory officials and researchers announced progress with the development ofseveral different kinds of vaccines, including:

• Officials of the Food and Drug Administration (FDA) in October approvedTrumenba, a vaccine to prevent invasive meningococcal disease caused byNeisseria meningitidis serogroup B in individuals 10 through 25 years of age.The vaccine is made by Wyeth Pharmaceuticals Inc., a subsidiary of Pfizer Inc.,in Philadelphia, Pa.

• A tetravalent vaccine directed against the Dengue virus proved effective inprotecting children against the virus, and use of the vaccine led to fewerhospitalizations during a phase 3 clinical trial in five Latin American countrieswhere dengue is endemic, according to Gustavo Horacio Dayan of SanofiPasteur in Swiftwater, Pa., and his collaborators. Details appeared 3 November2014 in the New England Journal of Medicine (doi:10.1056/NEJMoa1411037).

• An experimental nasal vaccine provides long-term protection for nonhumanprimates against the deadly Ebola virus, according to Maria Croyle of theUniversity of Texas at Austin and her collaborators. They reported recentfindings during the annual meeting of the American Association of Pharma-ceutical Scientists, held in San Diego, Calif., last November.

• A vaccine against the H1N1 influenza virus whose antigens were reformulatedis “six times more active” than are conventional versions of the flu vaccine “interms of hemagglutinin immunogenicity and in vivo protection,” according toManuel Rosa-Calatrava of VirPath and Emmanuel Dejean of Calixar, both inLyon, France.

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RESEARCH ADVANCES

Progress in Efforts ToHarness Yeast forMaking Opioid Drugs

Carol PoteraSaccharomyces cerevisiae, more com-monly known as baker’s yeast, is beingdeveloped as a means for producingopioid-based drugs, with the long-termgoal of making those drugs from glu-cose instead of extracting them frompoppy plants, according to ChristinaSmolke at Stanford University in Stan-ford, Calif., and her collaborators. Theyrecently reported progress toward thatgoal after inserting genes from thepoppy plant, Papaver somniferum, aswell as other genes from Pseudomonasputida M10, which grows on poppystraw waste, into yeast cells— enablingthem to produce opioids from inter-mediates that poppy plants make rela-tively early in that metabolic pathwayand to do so with improved effıciency.Details appear October 2014 in NatureChemical Biology (doi:10.1038/nchembio.1613).

Efforts to make such drugs in yeastprove to be painstaking, according toSmolke. In 2008, she and her collabo-rators engineered S. cerevisiae to pro-duce salutaridine, a precursor of the-baine, a biochemical intermediatealong the opioid biosynthetic pathway.“Salutaridine is just two enzymaticsteps upstream of thebaine itself,” shesays. In this more recent work, herteam introduced genes into yeast thatconvert thebaine into hydrocodone,oxycodone, and hydromorphone.These semisynthetic opioids are con-sidered safer and more effective thannatural opiates extracted from poppyplants. However, now they are pro-duced commercially by chemicalrather than biosynthetic means.

In three enzyme-catalyzed steps,poppy plants convert thebaine to mor-phine. Smolke and her collaboratorstook the genes that encode those threeenzymes—thebaine 6-O-demethylase(T6ODM), codeine O-demethlyase

(CODM), and codeinone reductase(COR)—and incorporated them into ayeast artifıcial chromosome (YAC).They also manipulated gene copynumbers and implemented other strat-egies to boost morphine yields. For ex-ample, they added two morphine dehy-drogenase genes (morA and morB)from P. putida M10 onto the YAC toenhance the synthesis of both hydro-codone and hydromorphine. Themodifıed yeast production strainschurn out 51 milligrams/liter (mg/l) ofhydrocodone, 70 mg/l oxycodone, and1 mg/l of hydromorphone, she notes.

However, to be commercially com-petitive, these yields need to be im-proved by another 10- to 100-fold, ac-cording to Smolke. “We’re optimizingthe [strains] to produce an integratedproduction system,” she says.

Efforts to develop a microbial fer-mentation system for making medi-cally valuable opioids from glucose“moved one important step closer,”says John Dueber, a bioengineer at theUniversity of California, Berkeley, re-garding the efforts of Smolke and hercollaborators to make opioids in yeast.

“Security measures will be required toprevent misuse,” he cautions.

Nonetheless, the availability of sucha means for producing opioids couldreduce our current reliance on farmedpoppies, which are subject not only toplant diseases and climate disruptionsbut also to illicit trade practices. Aus-tralia and Tasmania grow much of thepoppies used for legalized opioid pro-duction. Having engineered yeast as analternative means for making thesedrugs will help to make the supplychain more robust, Smolke says.Carol Potera is a freelance writer in Great Falls,Mont.

RESEARCH ADVANCES

Microorganisms in OceansMay Arise Faster thanCurrents Disperse Them

Barry E. DiGregorioMarine microorganisms appear to beevolving faster than they can disperse,perhaps accounting for their distinc-tive geographic patterns across severaloceans, according to microbial ecolo-

Field of opium poppies. Opium poppies are the source of both licit and illicit opioid drugs.Researchers are working on developing ways to use the yeast Saccharomyces cerevisisae tomanufacture both opioid compounds currently derived from the plants and and those currentlyproduced by chemical synthesis.

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gist Ferdi L. Hellweger from North-eastern University in Boston, Mass.,and his collaborators there and at theUniversity of New South Wales in Syd-ney, Australia. Their conclusions arebased on simulations of marine micro-bial geography, emphasizing genomicmutations embedded in models ofocean currents. Details appear in the

September 12, 2014 Science (345:1346 –1349).

“In a nutshell, microbes evolvefaster than the ocean currents can dis-perse them,” Hellweger says. “Even inan environment that is often consid-ered to be well-mixed, dispersal limita-tion can be substantial. This [fınding] isin contrast to the common notion that

microbes are not dispersal limited, orthat ‘everything is everywhere.’”

For their simulations of how micro-organisms move and evolve withinocean environments, Hellweger andhis collaborators modeled about100,000 individual cells that divide anddie, each with a 1-million-base-pair ge-nome subject to mutations. Becausethose mutations are set as neutral anddo not affect the growth or death of themicrobes, any patterns can be attrib-uted solely to neutral evolution andlimits on dispersal. They sampled thepopulation of cells at different timesand locations, and then compared theirDNA sequences using alignment tools.This analysis revealed emerging pat-terns, with microbial populations con-gregating in “provinces,” Hellwegersays. Differences between those prov-inces grow gradually but then periodi-cally collapse when populations co-alesce.

“The evolution and distributionmodel [developed by] Hellweger and hiscollaborators is an excellent example ofthe growing use of simulation to explorepotential hypotheses associated with bio-geographic distribution of microbial as-semblages,” says Jack A. Gilbert from theArgonne National Laboratory in Ar-gonne, Ill., who helps to coordinate theEarth Microbiome Project. “They iden-tify that microbial genomic evolutiondriven by local processes outweighs po-tential global mixing.

“The Earth Microbiome Project ischaracterizing the distribution of phy-logenetic units and functional geno-types across the world ecosystems, andsees the same principle of distribu-tion,” Gilbert continues. “Some . . .species, can be extremely well distrib-uted, but strain-level variants of thesespecies, some with extensive genotypicvariance and, hence, functional ecol-ogy, are highly localized in time andspace, exactly as predicted by this mod-el.”

“We hope to develop models withbetter predictive power and reconnectmodeling with contemporary observa-

MINITOPIC

First Set of 2015 Gut Microbiota Studies

Efforts to understand how microorganisms in the gut affect the hostcontinue to be part of the news. Microbe’s first set of examples for 2015include:

• The microorganisms in the gastrointestinal tracts of humans are lessdiverse than those found in African apes, according to Andrew Moellerand Howard Ochman at the University of Texas at Austin and theircollaborators. Details appeared 3 November 2014 in Proceedings of theNational Academy of Sciences (doi:10.1073/pnas.1419136111).

• Delivering fecal transplant material via capsules proves both effectiveand safe as a means for treating persistent infections with Clostridiumdifficile, according to Ilan Youngster at Massachusetts General Hospitaland Boston Children’s Hospital in Boston, Mass., and collaborators.Details appeared 5 November 2014 in the Journal of the AmericanMedical Association (doi:10.1001/jama.2014.13875).

• Lipopolysaccharides and peptidoglycans from the gut microbiota stim-ulate specific inflammatory pathways in peripheral blood mononuclearcells that are correlated with alcohol craving, according to Philippe deTimary and Peter Stärkel of Université Catholique de Louvain in Belgiumand their collaborators. Details appear November 1, 2014 in BiologicalPsychiatry (doi:10.1016/j.biopsych.2014.02.003).

• Lactobacillus species correlate, in the guts of mice, with mitigation oflupus symptoms, while Lachnospiraceae, a type of clostridium, correlatewith worsening, according to Xin Luo of Virginia Tech in Blacksburg andcollaborators. Details appeared 26 September 2014 in Applied andEnvironmental Microbiology (doi:10.1128/AEM.02676-14).

• Gut microorganisms produce �-butyrobetaine from carnitine in redmeat, giving rise to trimethylamine and trimethylamine-N-oxide, per-haps accounting for how meat accelerates atherosclerosis, according toStanley Hazen, of Lerner Research Institute and the Miller Family Heartand Vascular Institute at Cleveland Clinic in Cleveland, Ohio, and hiscollaborators. Details appeared 4 November 2014 in Cell Metabolism(doi:10.1016/j.cmet.2014.10.006

• Disrupting the circadian clock in the host alters the rhythms andcomposition of the gut microbial community, helping to account forobesity and metabolic problems, according to Eran Elinav of theWeizmann Institute of Science in Rehovot, Israel. Details appeared 23October 2014 in Cell (doi:10.1016/j.cell.2014.09.048).

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tions, like environmental metatran-scriptomics,” Hellweger says. Onelong-term goal is to model the trans-port of individual microbes in theoceans, taking into account their intra-cellular properties and behaviors, in-cluding genes, transcripts, proteins,and metabolism. “In this project,” headds, “we took a natural fırst step—modeling individuals with whole ge-nomes. Future work on microbe bio-geography will have to considerenvironmental selection and neutralevolution and dispersal limitation.”Barry E. DiGregorio is a freelance writer inMiddleport, N.Y.

NEW IN ASM JOURNALS

Engineered ChestnutWithstands Blight butSpares Fungi at Its Roots

David C. HolzmanChestnut trees that are genetically en-gineered to resist the pathogenic fun-gus Cryphonectria parasitica remaingood hosts for symbiotic fungi thatgrow along their roots, according toWilliam A. Powell of the SUNY Collegeof Environmental Science and Forestry(ESF) in Syracuse, N.Y., and his collab-orators. This sparing of benign fungihelps in overcoming a potentially im-portant regulatory concern, keepingthis transgenic variety of chestnut, Cas-tanea dentate, on track for eventualwidespread planting, he says. Detailsappeared 17 October 2014 in Appliedand Environmental Microbiology (doi:10.1128/AEM.02169-14).

“Before these trees can be used for arestoration program, they must betested and then reviewed by three fed-eral agencies—the U.S. Department ofAgriculture, the Environmental Pro-tection Agency, and the U.S. Food andDrug Administration,” Powell contin-ues. “The American chestnut tree wasone of the most abundant and impor-

tant keystone tree species in the easternforests of the U.S. Between three andfour billion of these trees were lost tothe exotic pathogen C. parasitica thatwas introduced into this countryaround 1900.” The American chestnutwas highly valued by the lumber indus-try for its fast growth and rot resis-tance. The wood was also used widelyfor making musical instruments andfurniture because it is both strong andlightweight.

The transgenic variety that Powelland his collaborators are testing is thefırst American chestnut tree varietythat is specifıcally engineered to with-stand that fungal blight. Its transgenefrom wheat produces an oxalic acid-degrading enzyme, oxalate oxidase,that targets C. parasitica. One potentialcomplication is that nonpathogenicmycorrhizal fungi that live in symbio-sis with the roots of trees, includingchestnuts, could be an unintended tar-get of that enzyme. Indeed, one impor-tant task of such fungi is to produceoxalic acid, presumably to enhance theuptake of minerals by causing biogeo-chemical weathering of minerals fromrock.

“We compared root colonizationamong the transgenic American chest-nut trees, wild-type American chestnuttrees, chestnut trees produced by tradi-tional hybrid breeding, and other treespecies typically found near chestnutsin the wild,” Powell says. “The majorrelevant result from this work is thatthe Darling 4 transgenic Americanchestnut does not differ in ectomycor-rhizal fungal associations from thewild-type chestnut.” These results holdtrue for trees grown in both green-house and fıeld settings.

These fındings address importantquestions “that will be required for reg-ulatory approval in order to releasetransgenic chestnut into the wild,” saysRonald Sederoff of North CarolinaState University in Raleigh. Unlike

many other developments involvingagricultural biotechnology, the “resto-ration of chestnut is not marketdriven,” he adds. “It has a primary ob-jective as a social benefıt, particularly tothe environment and to rural commu-nities. This difference should make theacceptance of a [transgenic] chestnutdifferent from most previous agricul-tural crops.”David C. Holzman is the Microbe JournalHighlights Editor.

MINITOPIC

Viral and FungalPathogens ThreateningSeveral Types ofAmphibians

The fungal pathogen Batrachochy-trium salamandrivorans, which led toa recent crash of wild fire salaman-ders in the Netherlands, will likelysoon reach the United States unlesssteps are taken to halt its spread,according to An Martel and FrankPasmans from Ghent University inBelgium and their collaborators.They find that the fungus probablyoriginated in Southeast Asia andreached Europe through the inter-national trade in Asian newts. De-tails appeared 31 October 2014in Science, (doi:101126/science.1258268). Meanwhile, two closelyrelated ranaviruses are causinghavoc among three species of am-phibians—the common midwifetoad, the common toad, and thealpine newt—in the Picos de EuropaNational Park in Spain, according toStephen Price of University CollegeLondon in London, England, and hiscollaborators. Details appeared 3November 2014 in Current Biology(http://dx.doi.org/10.1016/j.cub.2014.09.028).

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NEW IN ASM JOURNALS

New Method RapidlyDetermines Species andSusceptibility in BacterialInfections

Overprescription ofantibiotics is select-ing for antibioticresistance, contrib-uting to one of thegreat medical prob-lems of our time.Diagnosis of bacte-rial infections, and

determination of antibiotic suscepti-bility profıles are slow and tedious, andconsequently, patients may frequentlyreceive antibiotics to which their par-ticular infection is resistant. Now MatsNilsson and Dan I. Andersson ofUppsala University in Sweden and col-laborators have developed a generalmethod to rapidly identify culprit bac-teria species and determine their anti-biotic susceptibility profıles. An initial,short cultivation step to be conductedboth in the absence, and in the pres-ence of different antibiotics is com-bined with a sensitive species-specifıcpadlock probe detection of the bacte-rial target DNA, to determine whetherthe bacteria are growing or not, to in-dicate resistance versus susceptibility.In a proof-of-concept for urinary tractinfections, they applied the method todetermine the susceptibility profıle ofEscherichia coli for two drugs. Accu-racy was 100%; duration, just 3.5 hours.That, the investigators write, wouldminimize the need for prescribingbroad-spectrum antibiotics due to un-known resistance profıles of the treatedinfection.

(A. Mezger, E. Gullberg, J. Göransson, A. Zorzet, D.Herthnek, E. Tano, M. Nilsson, and D. I. Andersson.2014. A general method to rapidly determineantibiotic susceptibility and species in bacterialinfections. J. Clin. Microbiol. Online ahead of print19 November 2014; doi:10.1128/JCM.02434-14.)

Compounds Targeting DNAPackaging Enzymes ShowPromise against MalariaParasite

Malaria afflictsaround 200 millionpeople annually,killing more than600,000, mostly inAfrica, according tothe Centers for Dis-ease Control andPrevention. Now

Nicholas A. Malmquist of the PasteurInstitute, Paris, France, et al. show thatcompounds derived from inhibitors ofthe histone-modifying methyltrans-ferase enzymes kill malaria parasites inculture, as rapidly as the fastest-killingantimalarials available. They show fur-ther that these compounds are highlyeffective against multidrug resistantfıeld isolates from Cambodia, and clin-ical isolates of the two most prevalentspecies of human malaria, Plasmodiumfalciparum and P. vivax. Furthermore,the compounds kill the malaria para-sites specifıcally, that is, while remain-ing harmless to animal models and totheir microbiomes. Additionally, theykill the parasites in both the form theytakes in mosquitos, and in that inwhich they inhabit mammalian hosts.“All this suggests that this compoundseries can be developed into new anti-malarials effective at both killing andreducing transmission of the relevantparasites currently threatening peoplein endemic regions,” says Malmquist.

(N. A. Malmquist, S. Sundriyal, J. Caron, et al. 2014.Histone methyltransferase inhibitors: orallybioavailable, fast acting molecules with activityagainst different human malaria species.Antimicrob. Agents Chemother. Online ahead ofprint 24 November 2014; doi:10.1128/AAC.04419-14.)

Some Flu Viruses PotentiallyMore Dangerous Than Others

Certain subtypes ofavian influenza vi-ruses have the po-tential to causemore severe disease

in humans than do others. Jeffery K.Taubenberger of the National Instituteof Allergy and Infectious Disease et al.show that viruses expressing the avianH1, H6, H7, H10, or H15 hemaggluti-nins led to rapid weight loss and fatalpneumonia infections in mice andcaused more cell damage in normal hu-man lung cells than did avian influenzaviruses with other hemagglutinin sub-types. Conversely, mice infected withH2, H3, H5, H9, H11, H13, H14, andH16-expressing viruses suffered onlymild weight loss, with no signifıcantdisease. The team showed similar re-sults using hemagglutinins from two2013 H7N9 flu viruses from outbreaksin China. These results suggest thathemagglutinins may not require im-mune cells to trigger cell damage, butinstead may cause apoptosis or othermolecular processes that could lead tofatalities, says Taubenberger.

(L. Qi, L. M. Pujanauski, A. S. Davis, L. M.Schwartzman, D. S. Chertow, D. Baxter, K. Scherler,K. L. Hartshorn, R. D. Slemons, K.-A. Walters, J. C.Kash, and J. K. Taubenberger. 2014. Contemporaryavian influenza A virus subtype H1, H6, H7, H10,and H15 hemagglutinin genes encode amammalian virulence factor similar to the 1918pandemic virus H1 hemagglutinin. mBio 5:6;Published 18 November 2014, doi:10.1128/mBio.02116-14.)

Restrooms: Not as Unhealthyas You Might Think

Microbial succes-sion in a sterilizedrestroom beginswith bacteria fromthe gut and the va-gina, and is fol-lowed shortly byskin microbes. “We

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hypothesized that while enteric bacte-ria would be dispersed rapidly due totoilet flushing, they would not survivelong, as most are not good competitorsin cold, dry, oxygen-rich environ-ments,” says coauthor Jack A. Gilbertof San Diego State University in Cali-fornia. Instead, as expected, skin mi-crobes took over. Moreover, commu-nities associated with each surfacebecame increasingly similar in speciesand abundance within fıve hours ofsterilization, and remaining stable forthe remainder of eight weeks’ sam-pling. Ultimately, skin and outdoor-associated taxa comprised 68 –98% ofcultured communities, with fecaltaxa representing just 0 –15% ofthese. Outdoor-associated taxa pre-dominated prior to sterilization, andlong-term poststerilization, suggestingthat long-term, human bacteria mustbe dispersed in restrooms in order to bemaintained. Pathogens were not abun-dant, and methicillin-resistant Staphy-lococcus aureus was “Very rare,” saysGilbert.

Toilet seat samples, alone, clusteredaccording to restroom gender, withLactobacillus and Anaerococcus—vagi-nal flora— dominating women’s-roomtoilet seats, while the gut-associated

Roseburia and Blautia were more copi-ous on toilet seats in men’s rooms.

(S. M. Gibbons, T. Schwartz, J. Fouquier, M.Mitchell, N. Sangwan, J. A. Gilbert, and S. T. Kelley.2014. Ecological succession and viability ofhuman-associated microbiota on restroomsurfaces. Appl. Environ. Microbiol. Online ahead ofprint 14 November 2014; doi:10.1128/AEM.03117-14.)

Sleeping Sickness: ResearchSuggests Potential NovelIntervention Strategy

Approximately 60million people liveat risk for sleepingsickness, caused bytrypanosomes, no-tably T. brucei,while livestock in-fections, whichcause wasting dis-

ease, account for signifıcant economichardship in some of the most impover-ished regions of the planet. Treatmentsare toxic, and increasingly ineffective.Thus, new perspectives are needed ontrypanosome biology, transmission,and pathogenesis, in order to developnovel intervention strategies. Trypano-somes are capable of group-level be-havior, but mechanisms governing

T. brucei social motility have been un-known. Now Kent L. Hill and col-leagues of the University of California,Los Angeles report that a subset of re-ceptor-type adenylate cyclases in thetrypanosome flagellum regulate socialmotility. RNAi-mediated knockdownof adenylate cyclase 6 (AC6) or dualknockdown of AC1 and AC2 causes ahypersocial phenotype but has no dis-cernable effect on individual cells insuspension culture. Mutation of theAC6 catalytic domain phenocopiesAC6 knockdown, demonstrating lossof adenylate cyclase activity is respon-sible for the phenotype. Notably,knockdown of other ACs did not affectsocial motility, indicating segregationof AC functions. “These studies revealinteresting parallels in systems thatcontrol social behavior in trypano-somes and bacteria, and provide in-sight into a feature of parasite biologythat may be exploited for novel inter-vention strategies,” the investigatorswrite.

(M. A. Lopez, E. A. Saada, and Kent L. Hill. 2014.Insect stage-specific adenylate cyclases regulatesocial motility in African trypanosomes. Eukaryot.Cell. Online ahead of print 21 November 2014;doi:10.1128/EC.00217-14.)

Microbe—Volume 10, Number 1, 2015 • 11

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