Tag Archives: resistance

Untreatable bacteria identified in the US

A strain of E. coli resistant to last-resort antibiotics has been identified on United States soil for the first time. Health officials say this could be “the end of the road for antibiotics,” leaving us virtually helpless in fighting future infections.

Last month, researchers identified a 49-year-old Pennsylvania woman as the carrier for a strain of E. coli resistant to the antibiotic Colistin. The woman visited a clinic in Pennsylvania, which forwarded a sample to Walter Reed National Military Medical Center. Walter Reed found the bacteria in her urine.

Think of this drug as our nuclear option — it’s employed for particularly dangerous pathogens, when every other drug fails. This includes the CRE family, a group of germs so resilient and deadly that health officials have dubbed it “nightmare bacteria”. Infection with these superbugs ends up killing up to 50 percent of patients in some instances, and the CDC lists them among the country’s most urgent public health threats.

Finding a bug that can shrug off even Colistin on home soil “heralds the emergence of a truly pan-drug resistant bacteria,” say the authors of the paper detailing the discovery.

“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,” CDC Director Tom Frieden said in an interview Thursday.

This is the first known carrier of a Colistin-resistant strain in the United States. Last November, a report by Chinese and British researchers who found the Colistin-proof strain in pigs, raw pork meat and several people in China was met with shock by public health officials worldwide. The deadly strain was later discovered in Europe and elsewhere.

Escherichia coli (E. coli) naturally occurs in your gut and most strains are harmless. Some, however, can cause food-borne diseases with fever, nausea and vomiting to bloody diarrhea. The infections are transmitted by eating or drinking contaminated food and water. E. coli resistance for a spectrum of drugs has been increasingly reported in cases of urinary tract infections, and the WHO warns that the most widely used oral treatment — fluoroquinolones — are rapidly becoming ineffective. Seeing strains develop virtual immunity to any of our antibiotics is very bad news, Frieden says.

“I’ve been there for TB patients. I’ve cared for patients for whom there are no drugs left. It is a feeling of such horror and helplessness,” he added. “This is not where we need to be.”

The CDC and the Pennsylvania State Health Department mobilized immediately to investigate the case and to trace the patient’s contacts to see if the bacteria had spread. The CDC also said it is looking for other potential cases in the healthcare facility the patient visited.

The full paper, titled “Colistin resistance in the USA” has been published online in the journal Antimicrobial Agents and Chemotherapy and can be read here.

Low level of antibiotics cause drug resistance in ‘superbugs’

For years and years (good) doctors have warned about the dangers of taking antibiotics too lightly, which generally causes ‘bugs’ to be more resistant. More recently, a study conducted by researchers from Boston University showed that microbes are a lot like us: what doesn’t kill them makes them stronger, and this could have extreme consequences. Here’s what it’s about.

You’re sick, you go to the doctor, he gives you a prescription. You start taking it, after a couple of days feel all better, and stop taking it. The result is likely a strain of bacteria (or virus) that will be resistant to a whole number of drugs. The same thing could happen if you’re sick and instead of going to the doctor just take those pills you’ve got, and avoid going to the doctor alltogether.

superbugBasically, when administered in lethal levels, antibiotics trigger a fatal chain reaction within the bacteria that shreds the cell’s DNA. However, when the level is less than the lethal one, the results are not only the survival of the bacteria and the further resistance to this drug, but also to a whole series of other ones too.

“In effect, what doesn’t kill them makes them stronger,” said Collins, who is also a Howard Hughes Medical Institute investigator. “These findings drive home the need for tighter regulations on the use of antibiotics, especially in agriculture; for doctors to be more disciplined in their prescription of antibiotics; and for patients to be more disciplined in following their prescriptions.”

“We know free radicals damage DNA, and when that happens, DNA repair systems get called into play that are known to introduce mistakes, or mutations,” said Collins. “We arrived at the hypothesis that sub-lethal levels of antibiotics could bump up the mutation rate via the production of free radicals, and lead to the dramatic emergence of multi-drug resistance. The sub-lethal levels dramatically drove up the mutation levels, and produced a wide array of mutations,” Collins observed. “Because you’re not killing with the antibiotics, you’re allowing many different types of mutants to survive. We discovered that in this zoo of mutants, you can actually have a mutant that could be killed by the antibiotic that produced the mutation but, as a result of its mutation, be resistant to other antibiotics.”