Current Topics

RESEARCH ADVANCES

Melding Polio withRhinovirus To TreatBrain Tumors

Shannon Weiman

A modifıed poliovirus, under controlof a rhinovirus promoter gene, repli-cates exclusively in cancer cells and ap-pears effective against brain tumorswithout being neurotoxic, according toMatthias Gromeier of Duke Universityin Durham, N.C., and his collabora-tors. These treatments yield “miracu-lous results” in mice and appear safewhen tested in phase 1 clinical trials inpatients with brain tumors, he says.Gromeier presented recent fındingsduring the International Conferenceon Oncolytic Virus Therapeutics, heldlast April in Oxford, England.

Treatments for patients with glio-blastoma (GBM) are not very effec-tive—the chance of fıve-year survival is5%, while patients live on averageabout 14 months past their diagnosis.The poliovirus receptor, nectin-likemolecule-5 (Necl-5), is up-regulated intumor cells, making them particularlysusceptible to this virus, according toGromeier. “Necl-5 expression is abun-dant in GBM cells and tumor-associ-ated vasculature, and is implicated inGBM cell dispersion and invasion,” hesays.

Because poliovirus also infects anddamages healthy nerve cells, Gromeierand his collaborators needed to stripaway that capacity. They did so byswapping the polio sequence encodingthe internal ribosomal entry site (IRES)for one from rhinovirus to preventtranslation of poliovirus genes intoproteins. The resulting chimeric virus,called PV1(RIPO), is less virulent than

are attenuated poliovirus vaccinestrains when evaluated in nonhumanprimates, he says. Moreover, the chi-meric virus produces no toxic side ef-fects during phase 1 clinical trials, evenat the highest inoculum.

PV1(RIPO) effectively destroysGBM cells within 12 hours in vitro,Gromeier says. When PV1(RIPO) wasinjected directly into human-derivedGBM tumors that were implanted inmice, the tumors resolved in 18 of 25animals, whereas untreated tumorscontinued to grow. If mice were im-planted with two such tumors, a singleinjection of PV1(RIPO) destroyedthem both, indicating the chimeric vi-rus moves from one such tumor intoanother, he says.

Phase 1 clinical trials to evaluate the

safety of PV1(RIPO) for humans sug-gest it is also effective against glioblas-toma in those patients, according toGromeier. Since 2012, only 1 of 5treated GBM patients succumbed totumor growth, while 2 experienced re-mission without other treatments.These antitumor effects may depend inpart on host immune responses, hesays. “The human immune system istrained to recognize virus infectionsand, thus, responds vigorously to theinfected tumor.” This means for de-stroying GBM might be less likely toelicit resistance than are other treat-ments, he points out.

“The mechanism responsible forPV1(RIPO)’s effects against brain tu-mors broadly apply to almost all can-cers,” says Gromeier. “PV1(RIPO) nat-

Computer-enhanced image of a section through a brain showing a large glioblastoma (green,right) in one of the temporal lobes. Researchers have used a modified poliovirus to treatglioblastoma patients in phase 1 trials, with promising results. (Image © CNRI/Science Source.)

264 • Microbe—Volume 9, Number 7, 2014

CURRENT TOPICS

urally targets and destroys cancer cellsfrom most common cancer types: pan-creas, prostate, lung, colon, and manyothers.”

This approach to treating patientswith glioblastoma shows excellentpromise, says Subbiah Elankumaran ofVirginia Polytechnic Institute inBlacksburg, who is studying the New-castle disease virus as a means for treat-ing tumors. However, he warns, manyunexpected consequences can arisewhen taking experimental treatmentsthat work in mice and adapting them totreat humans.Shannon Weiman is a freelance writer in SanFrancisco, Calif.

RESEARCH ADVANCES

Methanogens Implicatedin Mass Extinction 250Million Years Ago

Barry E. DiGregorio

Methane-producing Methanosarcinaacetivorans microorganisms, which arefound in oil wells, deep-sea hydrother-mal vents, and oxygen-depleted sedi-ments, are now implicated as being re-sponsible for the cataclysmic Permian–Triassic (PT) extinction that occurredabout 250 million years ago, accordingto Daniel H. Rothman at the Massa-chusetts Institute of Technology inCambridge, Mass., and his collabora-tors in the United States and China.More specifıcally, the emergence thenof a new metabolic pathway “enabledeffıcient conversion of marine organiccarbon to methane,” they report. Thosemetabolic changes that led to release ofhuge amounts of methane combinedwith catastrophic volcanic activity mas-sively perturbed the atmosphere, ac-counting for mass extinctions every-where on Earth, they report. Detailsappeared in the March 31, 2014 Proceed-ings of the National Academy of Sciences(doi:10.1073/pnas.1318106111).

“The isotopic composition of car-bon deposited around the time of theextinction shows that the end-Permian

event is unequivocally accompanied bychanges in the carbon cycle,” Rothmansays. “That led us to seek the cause ofthose changes. We focused on the dy-namical behavior of the isotopicchanges. This allowed us to concludethat there was an exponential, or possi-bly super-exponential, burst of carbonadded to the oceans and atmosphere.”

Geologists and other scientists longspeculated that a surge in volcanic ac-tivity could account for the PT extinc-tions. However, isotopic changes dur-ing that period are not consistent withvolcanic activity accounting for such aburst, according to Rothman and hiscollaborators, who reasoned that mi-crobial communities are capable of ex-

ponential, or faster, growth. “Havingmade that realization, we then investi-gated the genomic record of microbialevolution,” he says. Their fırst effortswere to determine more precisely whenMethanosarcina, with its effıcient met-abolic pathway for producing methaneand acetate from carbon monoxide,likely emerged.

Rothman’s team used a combina-tion of carbon isotopic analysis, phylo-genetics, nickel analyses, and mathe-matical arguments to arrive at theirconclusion. Each exhibited their owntechnical diffıculties. “In many respectsthe hardest part of this work is the linkageof the disparate parts into a coherent hy-pothesis that not only makes sense mech-

MINITOPIC

First MERS Virus Cases in U.S. amongRecent Developments

Officials of the Centers for Disease Control and Prevention (CDC) in Atlanta, Ga., inMay notified the public of the first two cases of Middle East Respiratory SyndromeCoronavirus (MERS-CoV) appearing in the United States, each involving visitorswho brought the virus into the country. Other recent developments involving thisvirus include:

• Officials of the World Health Organization (WHO) in May said of MERS-CoV thatthe “seriousness of the situation had increased in terms of public healthimpact.” However, because evidence of sustained human-to-human transmis-sion is lacking, “conditions for a Public Health Emergency of InternationalConcern have not yet been met.”

• As of May 2014, MERS-CoV is responsible for 145 deaths among 536 infections,mainly from Saudi Arabia and the United Arab Emirates, according to WHOofficials.

• Infectious MERS-CoV from dromedary camels matches viral samples isolatedfrom infected humans, consistent with camels being a source of the virus inhuman cases, according to Thomas Briese and Ian Lipkin of the ColumbiaUniversity Mailman School of Public Health in New York, N.Y., and theircollaborators. Details appeared 29 April 2014 in mBio (doi:10.1128/mBio.01146-14). Virologists Norbert Nowotny and Jolanta Kolodziejek from the University ofVeterinary Medicine in Vienna, Austria, reported similar findings on 24 April2014 in Eurosurveillance.

• Neutralizing monoclonal antibodies can block this virus from entering cells invitro, according to Linqi Zhang of Tsinghua University in Beijing, China, and hiscollaborators. Details appeared 30 April 2014 in Science Translational Medicine(doi:10.1126/scitranslmed.3008140). Wayne Marasco of Dana Farber CancerInstitute in Boston, Mass., and his collaborators reported identifying generallysimilar neutralizing human antibodies 28 April 2014 in Proceedings of the NationalAcademy of Sciences (doi:10.1073/pnas.1402074111).

Microbe—Volume 9, Number 7, 2014 • 265

CURRENT TOPICS

anistically but also explains a signifıcantnumber of observations,” he says.

Methanosarcina bloomed explo-sively, spewing prodigious amounts ofmethane into the atmosphere, dramat-ically changing the climate as well asthe chemistry of the oceans. Mean-while, massive volcanism led nickellevels in sediments to increase abrupt-ly. Nickel is an essential component ofa key enzyme of methanogens, and thesurge in availability of this metal wascrucial for the Methanosarcina bloom,according to Rothman.

“The ideas presented in the Roth-man paper are not unreasonable, but Ithink it is fanciful to think that mi-crobes ‘caused’ the PT extinction,” saysDavid Bond from the University ofHull in the United Kingdom. “Maybethey played a part in the predicted vol-canism-climate change-anoxia-extinc-tion scenario, but we are still a long way

from understanding the actual causesof this event.” He also says that the newhypothesis provides a “highly plausiblemechanism for generating observedcarbon isotopic shifts.”

Barry E. DiGregorio is a freelance writer inMiddleport, N.Y.

PUBLIC HEALTH

Rules from 2005 EaseMatters for OfficialsCoping with Outbreaks

Jeffrey L. Fox

With their 10th anniversary looming,the International Health Regulations(IHR) of 2005 are gathering plenty ofpraise these days—a rarity for rules af-fecting practically every country on theplanet. Thus, despite diffıculties in im-plementing these rules and applyingcommon standards to disparate coun-

tries, IHR 2005 is “widely accepted”among the nearly 200 countries thatsigned the document, according toKeiji Fukuda of the World Health Orga-nization (WHO), which is charged withimplementing the rules. He spoke dur-ing a two-day workshop, “EmergingViral Diseases—the One Health Con-nection,” convened by the Institute ofMedicine (IOM) Forum on MicrobialThreats and held in Washington, D.C.,last March.

The IHR rules, which are meant “toprevent, protect against, control, andprovide a public health response to theinternational spread of disease in waysthat are commensurate with and re-stricted to public health risks, andwhich avoid unnecessary interferencewith international traffıc and trade,”require countries to “report certain dis-ease outbreaks and public health eventsto WHO.” The rules also require coun-tries to “strengthen core surveillanceand response capacities at the primary,intermediate, and national level. . . .”

The H1N1 influenza pandemic,whose initial outbreaks occurred earlyin 2009 fırst in Mexico and then in Cal-ifornia, provided the fırst test of IHR2005 and led to its fırst formal reviewthe following year, according to IOMPresident Harvey Fineberg. He was oneof 24 experts from as many countrieswho served on a World Health Assem-bly (WHA) committee to conduct thatreview. One “special challenge” for thecommittee was to hold its meetings opento the public, heading off criticisms that“WHO was being secretive,” he says.

The WHA committee came to sev-eral key conclusions about IHR 2005,according to Fineberg. First, the newrules “helped the world be better pre-pared” to cope with emerging diseases,even though many countries still fallshort in terms of their core capacitiesfor dealing with such emergencies, hesays. Another issue is that, althoughIHR 2005 rules are binding, enforce-ment measures are lacking and, in-stead, depend on what can be negoti-ated with or cajoled from each country.

MINITOPIC

WHO Documents Antibiotic Resistance, Polio, EbolaOutbreaks

World Health Organization (WHO) officials recently issued several reports withwarnings on worldwide antibiotic resistance, a resurgence of polio, and a majoroutbreak of Ebola virus in West Africa:

• In April, WHO officials released a comprehensive report on antibiotic resistance,“Antimicrobial resistance: global report on surveillance,” featuring data from114 countries and providing a global overview as well as region-by-regionanalyses of drug resistance patterns. It calls drug resistance a “major threat topublic health” and says that WHO is seeking “improved collaboration around theworld to track drug resistance, measure its health and economic impacts, anddesign targeted solutions.”

• In May, WHO warned that the recent spread of polio “constitutes an ‘extraor-dinary event’ and a public health risk . . . for which a coordinated internationalresponse is essential.” The “over-riding priority . . . must be to interrupt wildpoliovirus transmission . . . as rapidly as possible through . . . supplementaryimmunization campaigns with oral poliovirus vaccine, surveillance for poliovi-rus, and routine immunization.”

• Through early June in West Africa, Guinea reported 351 cases of Ebola,including 226 deaths, while Liberia reported 11 deaths among 12 suspectedcases of Ebola, and Sierra Leone reported 89 cases and 7 deaths, according toWHO officials. Meanwhile, this outbreak appears to be attributable to a newEbola virus variant, according to Delphine Pannetier of INSERM and SylvainBaize of Institut Pasteur in Lyon, France, and their collaborators. Details appeared16 April 2014 in the New England Journal of Medicine (doi.org/10.1056/NEJ-Moa1404505).

266 • Microbe—Volume 9, Number 7, 2014

CURRENT TOPICS

WHO takes great pains not to em-barrass individual countries for howwell or poorly they “measure up,” andthis low-key approach ends up being a“core problem,” Fineberg says. Al-though the idea of WHO helping inefforts to assess a country’s capacity todeal with emerging infectious diseases“makes sense, national governmentsdon’t like it,” Fukuda adds, noting thatonly about 20% of the countries havethe appropriate capacity. “WHO iswell-positioned to help with quality as-sessments, but we haven’t found theright way to achieve the necessary po-litical balance.”

Another looming issue is how bestto deal with the Convention on Biolog-ical Diversity (CBD), an internationalagreement from 1992 that was neverintended to deal with public health is-sues. Nonetheless, some of its provi-

sions bump into matters concerningIHR 2005, particularly when it comesto sharing of biological materials that,for example, might prove critical forthe development of diagnostic testsand vaccines. “What can you do?” Fu-kuda asks. “This framework [the CBD]is seen as being ‘over there,’ havingnothing to do with health, but we real-ize it does.”Jeffrey L. Fox is the Microbe Current Topics andFeatures Editor.

NEW IN ASM JOURNALS

Freely DiffusingTopical Antifungal AgentFixes Infected ToenailsDavid C. Holzman

The candidate antifungal drug efına-conazole is proving effective againsttoenail infections. The drug diffuses

relatively freely through nails andbinds less strongly to keratin than doother topically applied antifungaldrugs, leaving it free to fıght the fungus,according to Keita Sugiura of KakenPharmaceutical of Kyoto, Japan, andhis collaborators. “This study suggeststhat . . . low keratin affınity is neededfor favorable penetration and retentionof antifungal activity within the nailmatrix,” he says. Details appeared on-line 21 April 2014 and will be printed inthe July 2014 Antimicrobial Agents andChemotherapy.

Because topical antifungal drugs sooften fail to cure this condition, physi-cians sometimes prescribe oral anti-fungal drugs such as terbinafıne anditraconazole for some of their patientswith stubborn cases of onychomycosis.However, Sugiura points out, this ap-proach “is limited” because such drugscan damage the liver or may interactwith other drugs that patients are tak-ing. Although topically applied anti-fungal drugs such as ciclopirox andamorolfıne have “a favorable safetyprofıle,” he adds, “their cure rates areconsiderably lower.”

Sugiura and his collaborators testedhuman nails to fınd how well the drugdiffuses through keratin-rich nails.Small 16 mm2 squares from commer-cially available toenail material (whoknew?) were mounted in Franz diffu-sion cells to measure how quickly sev-eral antifungal drugs pass through thatmaterial. Efınaconazole proved speedi-est, racing through the mounted nailsquares within the fırst day, whileciclopirox took six days and amorolfıneremained undetected, they report.

Of several drugs tested, only efına-conazole inhibited fungal growth un-der nails in vitro, according to Sugiura.He and his collaborators also tested thefungicidal activity of several topical an-tifungal products in a fluid keratin me-dium that is designed to “mimic thekeratin-rich environment of the nailplate and nail bed.” Without a solid ma-trix to block the drugs, efınaconazoleproved slightly more potent at killing

MINITOPIC

Shapes and Curves; Plus Revised Viewof Cell-Wall Growth

The shapes of microbial species are sometimes fanciful and can be important fortheir survival or may mask activities that are key to physiology. Recent examplesinclude:

• Helicosporidium, a corkscrew-shaped intracellular parasite that feeds on juve-nile insects, derived from algae but, unlike Plasmodium, the parasite responsi-ble for malaria which also derived from algae, retained most of its genes exceptthose explicitly needed for photosynthesis, according to Patrick Keeling of theUniversity of British Columbia (BC) in Vancouver, B.C., Canada, and hiscollaborators. Details appeared 8 May 2014 in PLoS Genetics (doi:10.1371/journal.pgen.1004355).

• In gently moving water, the curvature of Caulobacter crescentus cells helps topoint progeny swarmer cells toward the surface, where they go to attach tosimilar cells, enlarging the growing colony, according to Alexandre Persat andZemer Gitai at Princeton University and their collaborators. Details appeared 8May 2014 in Nature Communications (doi:10.1038/ncomms4824).

• The cell wall enzyme PBP2 and the bacterial actin homolog MreB are active ondrastically different time scales, suggesting that cell wall growth in gram-negative bacteria depends on dynamic instead of stable complexes involvingthese and other proteins, according to K. C. Huang of Stanford University inStanford, Calif., and his collaborators. Thus, for example, the cell wall keepsgrowing under osmotic stress but the new segments remain shriveled untilconditions allow them to expand and take their rightful shape. Detailsappeared 12 May 2014 in the Proceedings of the National Academy of Sciences(doi:10.1073/pnas.1313826111).

Microbe—Volume 9, Number 7, 2014 • 267

CURRENT TOPICS

the fungus than did amorolfıne and farmore potent than ciclopirox, they note.

“Efınaconazole is the fırst topicaldrug that has shown effıcacy for thispersistent and common infection,”says Boni Elewski of the University ofAlabama, Birmingham, who last yearled a pair of phase 3 clinical studies toevaluate this drug for treating onycho-mycosis, the formal name for chronicfungal infections of toenails. “I thinkthis mechanism of action is indeedquite signifıcant, contributing to the rel-atively high mycologic cure rate in treat-ing onychomycosis,” says Elewskii.

The typical fungi responsible for on-ychomycosis include Trichophytonrubrum, T. mentagrophytes, Candidaalbicans, and nondermatophyte molds.The condition affects about 8% of theU.S. population, mainly adults, partic-ularly those who are 60 years of age orolder. While more a cosmetic than afrank health issue, onychomycosis canprove painful as well as being an eye-sore, and may interfere with work thatentails standing, food handling, mod-eling, or other interactions and rela-tionships, Elewski points out.David C. Holzman is the Microbe JournalHighlights Editor.

RESEARCH ADVANCES

PromisingTuberculosisDrug also TargetsVastly DifferentMicrobesCarol PoteraA promising candidate drugfor treating tuberculosis(TB), called SQ109 and un-dergoing phase 2 clinicaltrials, acts against Myco-bacterium tuberculosis aswell as other microbialpathogens and parasites viaseveral different mecha-nisms, according to EricOldfıeld at the Universityof Illinois, Urbana-Cham-paign, and his collabora-

tors. Not only SQ109, but also a seriesof analogues inhibit the growth of arange of microorganisms, acting at var-ious molecular targets—leading to“very low rates of spontaneous drugresistance,” they report. “There’s an ur-gent need for new drugs that are resis-tance-resistant, and drugs that hit mul-tiple targets will reduce resistance,”Oldfıeld adds. Details appeared Febru-ary 25, 2014 in the Journal of MedicinalChemistry (doi:10.1021/jm500131s).

SQ109 is a 1,2-diamine that is re-lated to ethambutol, a widely used drugthat is bacteriostatic against M. tuber-culosis, blocking cell-wall production.Sequella, Inc. in Rockville, Md., a com-pany focused on TB, began developingSQ109 in 2000, then in partnershipwith researchers at the National Insti-tutes of Health (NIH) in nearbyBethesda, Md. Several years ago, mem-bers of the NIH group and their collab-orators reported that SQ109 “interfereswith the assembly of mycolic acids intothe cell wall core of M. tuberculosis.”They also concluded that the primarybacterial target for the drug wasMmpL3, “a transporter of trehalosemonomycolate,” an ingredient of thecell wall in M. tuberculosis.

That seeming clarity for how SQ109

and analogues like it work, however,proved to be less than complete. Otherresearcher groups reported that SQ109acts against other microbial species, in-cluding Helicobacter pylori bacteriaand Candida albicans, a yeast. Neitherone of them produces the MmpL3transporter or makes cell walls likethose of M. tuberculosis. Those andother results suggest that there must beother cellular targets for SQ109 and itsanalogues.

Oldfıeld and his collaborators testedSQ109 and a series of analogues againsta battery of fıve bacteria, including M.

MINITOPIC

Synthetic Biology:Microbe Reaches FirstBase with OddNucleotides

An engineered version of Escherichiacoli can grow normally while stablycarrying unnatural nucleotide basepairs within a replicating plasmid,according to Floyd Romesberg ofthe Scripps Research Institute in LaJolla, Calif., and his collaborators.Triphosphate versions of those un-natural base pairs, designatedd5SICS and dNaM, are brought intothe E. coli bacterial cells via an algaltransporter protein, and the DNAreplication machinery of those cells“uses them to accurately replicate aplasmid,” they report. The bacterialDNA repair apparatus leaves the al-tered plasmids alone, and the addi-tion of the synthetic base pairs,which are not being translated intonovel amino acids, does not appearto slow down the growth of thealtered cells. Their next step in thisresearch, Romesberg and his collab-orators say, “will be to demonstratethe in-cell transcription of the new,expanded-alphabet DNA into theRNA that feeds the protein-makingmachinery of cells.” Details ap-peared May 7, 2014 in Nature (doi:10.1038/nature13314).

Fungal infections of toenails are particularly difficult totreat, chiefly because it is difficult to get antifungals topenetrate the nail. A new topical antifungal, efinacona-zole, shows good penetration into infected nails and maybe a breakthrough for treating infections that previouslycould only be treated with orally administered drugs.(Image © iStockphoto/4kodiak.)

268 • Microbe—Volume 9, Number 7, 2014

CURRENT TOPICS

tuberculosis, M. smegmatis, Staphylococ-cus aureus, Bacillus subtilis, and Esche-richia coli, the two yeasts Saccharomycescerevisiae and Candida albicans, and themalaria parasite Plasmodium falciparum.They also subjected human cells (cell lineMCF-7) to those compounds to gaugetheir relative toxicities.

Two of the analogues are 4 to 5 timesmore potent than is SQ109 against M.tuberculosis in vitro, and one of them is4 times less toxic against the human cellline. The compounds show varied ac-tivity against the other bacteria, yeasts,and P. falciparum—in general, target-ing several different enzymes, includ-ing ones involved in menaquinone bio-synthesis, electron transport, and inhi-bition of ATP biosynthesis.

“SQ109 and related compoundsmay be acting by a combination ofmutually reinforcing mechanisms,”says Julio Urbina, emeritus investiga-tor at the Venezuelan Institute forScientifıc Research, near San Antoniode los Altos in Altos de Pipe, MirandaState. “This may explain their po-tency and suggests that they couldrepresent a novel class of broad-spec-trum anti-infective drugs, activeagainst bacterial, fungal, and proto-zoan pathogens.”

“I hope the pharmaceutical indus-try, which has shown a distressing lackof interest in the discovery of antibiot-ics, will be stimulated by work like Old-fıeld’s,” says Andrew McCammon, aHoward Hughes Medical Institute In-vestigator and distinguished professorof pharmacology at the University ofCalifornia, San Diego. Another plus, headds, is that these antibiotic candidateshave “the remarkable property of in-hibiting not just one, but several essen-tial cellular functions in pathogenicbacteria, fungi, and the malaria para-site.” Such antimicrobial products, ifused clinically, thus might be less proneto stimulating the development of drugresistance in pathogens.

Carol Potera is a freelance writer in Great Falls, Mont.

NEW IN ASM JOURNALS

Evolution of Equine InfluenzaVirus Led to Canine Offshoot

Influenza A virusesmutate rapidly, andhave entered newhosts in recent his-tory, sometimeswith devastatingconsequences.Pablo Murcia of theUniversity of Glas-

gow, et al. show that equine influenzavirus (EIV) from 1963 infected caninetracheal explant cultures only verymildly, while 2003 EIV, from which ca-nine influenza virus was derived,around that time, replicated vigorouslyand caused ample lesions. Murcia alsoshowed that CIV and human influenzavirus could mix, generating viable chi-meras that infected dog tracheas, saysMurcia. That, he says, means that suchchimeric viruses might occur naturally,and would likely be able to infect dogs.Studies investigating whether they couldinfect human lungs are underway.

(G. Gonzalez, J. F. Marshall, J. Morrell, D. Robb, J. W.McCauley, D. R. Perez, C. R. Parrish, and P. R.Murcia. 2014. Infection and pathogenesis ofcanine, equine and human influenza viruses incanine tracheas. J. Virol. Online ahead of print 4June 2014; doi:10.1128/JVI.00887-14.)

NEW IN ASM JOURNALS

Australian ResearchersSharpen Test for TracingFoodborne Illness to Source

When food poison-ing occurs, it’s criti-cal to determine thesource. The MLVAtest compares mul-tiple sections ofSalmonella’s mostrapidly mutatinggenomic region in

food source and patient: a match ispowerful positive evidence. Now Aus-tralian investigators have found thatSalmonella MLVA regions change at

different rates. They have used that in-formation to write new rules for defın-ing Salmonella outbreak clusters, toboost the test’s accuracy. They alsoshow that relative rates of change arethe same in both in vitro and mousestudies. The test is the primary methodfor investigations of outbreaks of Sal-monella and other foodborne patho-gens in Europe, the United Kingdom,and Australia, says corresponding au-thor Kathryn Holt, of the University ofMelbourne. In the United States, theCenters for Disease Control and Pre-vention uses another technique, PFGE,for initial investigations, which are fol-lowed by MLVA tests.

(K. Dimovski, H. Cao, K. E. Holt, et al. 2014. Analysisof Salmonella enterica serovar Typhimuriumvariable-number tandem-repeat data for publichealth investigation based on measured mutationrates and whole-genome sequence comparisons.J. Bacteriol. Online ahead of print 23 June 2014;doi:10.1128/JB.0182-14.)

NEW IN ASM JOURNALS

Fermentation of CocoaBeans Requires PreciseCollaboration amongTwo Bacteria and Yeast

One can always workto make a good thingbetter. That spiritmotivated a team ofresearchers who in-vestigated cocoa beanfermentation. Thekey molecule to initi-

ate flavor development is acetate, saysPI Christoph Wittmann, of SaarlandUniversity, Saarbruecken, Germany.Production of acetate requires two ma-jor nutrients: lactate and ethanol.These are produced by lactic acid bac-teria and yeast, respectively, during theinitial fermentation of cocoa pulp sug-ars, says Wittmann. He and his collab-orators show, in a lab simulation ofcocoa fermentation, that the acetic acidbacteria then process the two com-pounds simultaneously, via separatemetabolic pathways, and then produce

Microbe—Volume 9, Number 7, 2014 • 269

CURRENT TOPICS

acetate. They performed the mappingby feeding the bacteria specifıc isotopesthat could easily be tracked. “This dis-covery reveals a fıne-tuned collabora-tion of a multispecies consortiumduring cocoa fermentation,” says Wit-tmann. And that, he says, may help im-prove selection of natural strains forbetter-balanced starter cultures.

(Adler, P., L. J. Frey, A. Berger, C. J. Bolten, C. E.Hansen, and C. Wittmann. 2014. The key toacetate: Metabolic fluxes of acetic acid bacteriaunder cocoa pulp fermentation simulatingconditions. Appl. Environ. Microbiol. Online aheadof print 16 May 2014; doi:10.1128/AEM.01048-14)

NEW IN ASM JOURNALS

Improved Identificationof War Wound Infectionsfor Better Treatment

Culture-based iden-tifıcation, used toassay war wound in-fections, misses themany species that arediffıcult or impossi-ble to culture. ButNicholas Be of Law-rence Livermore

National Laboratory, Livermore, Calif.,et al. posited that using microarraysand whole-genome sequencing to de-tect microbial species in wound sam-ples would reveal unculturable infec-tions, says Be. “We also hypothesized[correctly] that different microorgan-isms could be associated with successfulor unsuccessful healing, and we felt thatthis information could be used forguiding medical treatment,” he says.Genetic sequences from certain bacte-ria, including Pseudomonas speciesand Acinetobacter baumannii, werefrequently observed in wounds thatfailed to heal, while bacteria typicallyassociated with the gastrointestinalsystem, such as Escherichia coli andBacteroides species, were found inwounds that did heal successfully.

“This surprising fınding further em-phasizes the need for specifıc molecu-lar detection,” says Be. “Microbial pop-ulations present in wounds varybetween patients and change over timein a single patient, further emphasizingthe need for personalized treatment ofindividual wounds,” he adds.

(Be, N. A., J. E. Allen, T. S. Brown, S. N. Gardner, K. S.McLoughlin, J. A. Forsberg, B. C. Kirkup, B. A.Chromy, P. A. Luciw, E. A. Elster, and C. J. Jaing.2014 Microbial profiling of combat woundinfection through detection microarray andnext-generation sequencing. J. Clin. Microbiol.Online ahead of print 14 May 2014; doi:10.1128/JCM.00556-14.)

NEW IN ASM JOURNALS

Bacteria Armed withAntibiotic Resistance EnzymeProtect Gut Microbiome

Antibiotics kill the“good” (commen-sal) bacteria, alongwith the bad. Theymay render patientsvulnerable to inva-sion, particularly bythe virulent, antibi-

otic-resistant pathogens that fre-quently populate hospitals. But now ateam of researchers shows that popu-lating the GI tracts of mice with Bacte-roides species producing beta-lacta-mase protected the commensalbacteria from systemic antibiotics.Ironically, beta-lactamase is a majorcause of resistance to beta-lactamantibiotics, but since the Bacteroides,which comprise roughly one-quarterof the intestinal microbiome, are ab-sent elsewhere in the body, the investi-gators hypothesized that this would notblock treatment of infections in otherorgan systems, says fırst author UshaStiefel of Case Western Reserve Uni-versity, Cleveland, Ohio.

(Stiefel, U., M. M. Nerandzic, M. J. Pultz, and C. J.Donskey. 2014. Gastrointestinal colonization with

a cephalosporinase-producing Bacteroidesspecies preserves colonization resistance againstvancomycin-resistant Enterococcus andClostridium difficile in cephalosporin-treatedmice. Antimicrob. Agents Chemother. Onlineahead of print 27 May 2014; doi:10.1128/AAC.02782-14.)

NEW IN ASM JOURNALS

New Halophilic Bacteriumfrom Hypersaline Ponds

Spiribacter salinus, agammaproteobacte-rium of new genusand species, appearsto be the most abun-dant species in hyper-saline saltern pondsof medium (12–20%)

salinity, comprising about 15% ofthe bacterial population, according toAn-tonio Ventosa of the Universityof Seville, Spain. “These microbesnever isolated before could be used asmodel organisms in order to under-stand the relationships and activitiesof microbes in natural environ-ments,” says Ventosa. “Our studiesindicate that many microorganismsused classically as model organismsare not abundant—in some cases rep-resenting less than 1% of the totalmicrobial population, and thus, arenot ideal for understanding adaptiveand stress mechanisms of microbesin extreme conditions.” The meta-genomic techniques used for thesestudies could be used to isolate thepredominant microbes in other hab-itats that are as yet uncultured, hesays, noting additionally that ex-tremophiles are important for studiesin astrobiology.

(Leon, M. J., A. B. Fernández, R. Ghai, C.Sánchez-Porro, F. Rodriguez-Valera, and A.Ventosa. 2014. From metagenomics to pureculture: isolation and characterization of themoderately halophilic bacterium Spiribactersalinus gen. nov., sp. nov. Appl. Environ. Microbiol.80:3850 –3857; doi:10.1128/AEM.01433-14.)

270 • Microbe—Volume 9, Number 7, 2014

CURRENT TOPICS