* Cameron urges G7 to back reward system for new drugs
* U.S. sees first case of resistance to last-resort drug
* Antimicrobial resistance moving up political agenda (Adds details on problem in U.S., China and Europe)
By Kylie MacLellan and Ben Hirschler
ISE-SHIMA, Japan/LONDON, May 27 (Reuters) - Britain told theG7 industrial powers on Friday to do more to fight killersuperbugs as the United States reported the first case in thecountry of a patient with bacteria resistant to a last-resortantibiotic.
U.S. scientists said the infection in a 49-year-oldPennsylvania woman "heralds the emergence of truly pan-drugresistant bacteria" because it could not be controlled even bycolistin, an antibiotic reserved for "nightmare" bugs.
In Japan, British Prime Minister David Cameron said leadingcountries needed to tackle resistance by reducing the use ofantibiotics and rewarding drug companies for developing newmedicines.
"In too many cases antibiotics have stopped working. Thatmeans people are dying of simple infections or conditions likeTB (tuberculosis), tetanus, sepsis, infections that should notmean a death sentence," he told a news conference at a summit inJapan.
"If we do nothing about this there will be a cumulative hitto the world economy of $100 trillion and it is potentially theend of modern medicine as we know it."
A review commissioned by the British government andpublished last week said a reward of between $1 billion and $1.5billion should be paid for any successful new antimicrobialmedicine brought to market.
If the problem is not brought under control, antimicrobialresistance could kill an extra 10 million people a year by 2050,the review warned.
The U.S. case is a further wake-up call for the world,although it is not the first time that colistin resistance hasappeared.
Medics around were alarmed last year by the discovery inChina of a new gene that makes bacteria highly resistant to themedicine. Since then, the deadly strain has also been detectedin Europe and Canada.
The development of colistin resistance is linked to thedrug's widespread use in livestock and the European MedicinesAgency on Thursday called for a 65 percent cut in the amount ofthe medicine used in farming.
"The more we look at drug resistance, the more concerned weare," Thomas Frieden, director of the U.S. Centers for DiseaseControl and Prevention, told reporters in Washington.
"The medicine cabinet is empty for some patients. It is theend of the road for antibiotics unless we act urgently."
The problem is aggravated by drugmakers' reluctance toinvest in developing new antibiotics, preferring to focus onmore profitable disease areas, although recently there has beensome increase in investment, prompted by the superbug threat.
In January, 83 companies, including Pfizer, Merck &Co, Johnson & Johnson and GlaxoSmithKline, signed a declaration urging governments to support workon new antibiotics. (Reporting by Kylie MacLellan; Writing by Elizabeth Piper;Editing by Louise Ireland)