Second Patient in US is Infected with 'Superbug' Resistant to ALL Antibiotics

• 2nd person infected with E.coli that carries the mcr-1 'superbug' gene
• Gene makes the bacteria resistant to last-resort colistin antibiotics
• Follows discovery of woman in Pennsylvania who had urinary tract infection caused by E.coli that carried the same gene

A second patient in the US has been infected with bacteria carrying the mcr-1 'superbug' gene, which makes the bug highly resistant to a last-resort class of antibiotics, experts have said.


The gene, found in a sample of E. coli bacteria from a patient in New York, follows the discovery late last month of a patient in Pennsylvania who had a urinary tract infection caused by E. coli that carried the same gene.

The finding was published on Monday in Antimicrobial Agents and Chemotherapy, a journal of the American Society for Microbiology.



A second patient in the US has been infected with bacteria carrying the mcr-1 'superbug' gene, which makes the bug highly resistant to a last-resort class of antibiotics, experts have said

The mcr-1 gene makes bacteria resistant to colistin, an antibiotic used to treat multi-drug-resistant infections, including carbapenem-resistant Enterobacteriaceae or CRE, which US health officials have dubbed a 'nightmare' bacteria.

Colistin is the last antibiotic used to combat bacteria that are resistant to the strongest antibiotics.

The drug has remained the best tool available to treat multi-drug resistant bacteria, because bacteria were not exchanging genes that triggers resistance.

The latest discovery shows that colistin may be losing its effectiveness in antimicrobial therapy.

What is concerning about the mcr-1 gene discoveries in the United States is that bacteria have the capability to share resistance genes.

US officials are worried that the mcr-1 gene may find its way into CRE bacteria, potentially creating bacteria resistant to virtually all types of antibiotics.

Scientists have been tracking the mcr-1 gene's movement around the globe since it was discovered last year in people and pigs in China.

The latest US finding of mcr-1 came as part of a global effort called the SENTRY Antimicrobial Surveillance Program, led by Mariana Castanheira of JMI Laboratories based in North Liberty, Iowa.

Researchers tested 13,525 Escherichia coli and 7,481 Klebsiella pneumoniae strains from patients collected last year from hospitals in the Asia-Pacific region, Latin America, Europe and North America.

Of these, 390, or 1.9 per cent, were resistant to colistin, and 19 of these isolates tested positive for the mcr-1 gene.

Samples carrying the gene came from 10 countries and included some from each region.

Only one came from the United States.

It involved a New York patient infected with E. coli whose name and condition were not disclosed.

In both US cases, bacteria that carried the 'superbug' gene were resistant to colistin but susceptible to a number of other antibiotics, making the infections treatable.



The gene, found in a sample of E. coli bacteria from a patient in New York, follows the discovery late last month of a patient in Pennsylvania who had a urinary tract infection caused by E. coli (illustrated) that carried the same gene

In May, health officials revealed a woman in Pennsylvania had become the first American to test positive for the mcr-1 'supergene'.

Experts said at the time, the alarming discovery heralded 'the emergence of truly pan-drug resistant bacteria'.

Researchers from the Walter Reed Army 6 Institute of Research in Maryland revealed the bacteria was identified in the urine of a 49-year-old woman.

She presented at a clinic in Pennsylvania in April, with symptoms indicative of a urinary tract infection.

The woman's urine sample was sent to the Walter Reed National Military Medical Center for testing.

The results showed no safe dosage of colistin would be effective to treat such a bacterial infection.

The researchers warned: 'The recent discovery of a plasmid-borne colistin resistance gene, heralds the emergence of truly pan-drug resistant bacteria'.

CDC director, Dr Tom Frieden, said: 'It basically shows us that the end of the road isn't very far away for antibiotics, that we may be in a situation where we have patients in our intensive-care units, or patients getting urinary tract infections for which we do not have antibiotics,' the Washington Post reported.

To keep track of the spread of this resistance gene in the United States, the Centers for Disease Control and Prevention has disclosed plans to expand laboratory capacity to seven or eight regional laboratories, plus add capacity to laboratories in each US state as well as seven cities or territories.

In the United States, antibiotic resistance causes at least two million illnesses and 23,000 deaths annually.

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