Cosmos - - Contents -

— End of one era, dawn of an­other

WE’RE NEAR­ING THE end of the an­tibi­otic era. Ever since peni­cillin be­came widely avail­able af­ter 1945, peo­ple stopped wor­ry­ing about in­fec­tions. Sore throats or in­fected cuts were quickly sorted out by an­tibi­otics from a kindly doc­tor fol­lowed by a few days in bed. Later gen­er­a­tions quickly for­got that sim­ple in­fec­tions could be deadly.

An­tibi­otics were such a won­der­ful cure-all that doc­tors pre­scribed them with aban­don, like sweets. They weren’t just good for cur­ing in­fec­tions in peo­ple: they also had a sur­pris­ing side ef­fect as growth ac­cel­er­a­tors for chick­ens, pigs and cows. As a re­sult, an­tibi­otics have flooded our en­vi­ron­ment. This has killed off a lot of mi­crobes, but left room for their an­tibi­otic-re­sis­tant rel­a­tives to thrive. It’s a text­book ex­am­ple of evo­lu­tion: when the en­vi­ron­ment changes, the fittest in­di­vid­u­als gain the up­per hand and mul­ti­ply.

The ranks of an­tibi­otic-re­sis­tant mi­crobes have now swelled dra­mat­i­cally. You might en­counter a re­sis­tant strain of golden staph dur­ing rou­tine surgery in an Aus­tralian hos­pi­tal, or a trip to New Guinea might land you with a mul­tidrug-re­sis­tant strain of tu­ber­cu­lo­sis.

In 2016, the UK govern­ment com­mis­sioned econ­o­mist Jim O’neill to mea­sure the scale of the cri­sis. He found 700,000 peo­ple die each year due to in­fec­tions by drug-re­sis­tant mi­crobes. By 2050, that fig­ure will rise to 10 mil­lion if noth­ing is done.

One re­sponse is to try to turn the ta­bles on the en­emy by tak­ing away its se­lec­tive ad­van­tage. By slow­ing the tap that drips an­tibi­otics into the en­vi­ron­ment, par­tic­u­larly into farm an­i­mals, we can make life eas­ier for an­tibi­otic-sus­cep­ti­ble mi­crobes, which should slow the ad­vance of the re­sisters.

Mean­while, we are in dire need of a new gen­er­a­tion of weaponry. Our lead story this is­sue takes a look at what’s in the pipe­line. One ap­proach looks back in time.

Peni­cillin was de­vel­oped in re­sponse to the cri­sis of the Sec­ond World War. But the First World War had led to an­other an­tibac­te­rial treat­ment: like fleas that have lit­tler fleas on their backs to bite ’em, bac­te­ria them­selves are prey to tiny viruses called bac­te­rio­phages.

Bac­te­rio­phage ther­apy was su­per­seded by the use of peni­cillin and other an­tibi­otics, which was eas­ier to in­dus­tri­alise. But East­ern Euro­pean coun­tries have con­tin­ued to use bac­te­rio­phages to treat in­fec­tions. Be­cause phages can out­com­pete bac­te­ria in the evo­lu­tion­ary arms race, they are an im­por­tant weapon to which many Western re­searchers are now re­turn­ing.

Oth­ers are ex­plor­ing new strate­gies. These in­clude “de­fang­ing” dis­ease-caus­ing bac­te­ria with­out killing them, us­ing a deadly phage ex­tract called lysin as a drug, or stop­ping over­growth in bac­te­rial ecosys­tems us­ing com­pounds called “quo­rum quenchers”.

We’re wit­ness­ing the birth of a smart new ar­se­nal de­signed with an eye to be­ing evo­lu­tion-proof. Gain hope from read­ing Dyani Lewis’s re­port.

EL­IZ­A­BETH FINKEL Ed­i­tor-in- chief

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