Category Archives: Antibiotics

‘Virtually untreatable’ TB found

TB presently causes about 1.7 million deaths a year worldwide, but researchers are worried about the emergence of strains that are resistant to drugs.

Drug resistance is caused by poor TB control, through taking the wrong types of drugs for the incorrect duration.

Multi-drug resistant TB (MDR TB), which describes strains of TB that are resistant to at least two of the main first-line TB drugs, is already a growing concern.

Globally, the WHO estimates there are about 425,000 cases of MDR TB a year, mostly occurring in the former Soviet Union, China and India.

Beneficial Bacteria

Sick of Getting Sick? Embrace Your Inner Bacteria!, NPR:

Over there, one type of bacteria has settled into a tidy corner of your intestine and is helping to synthesize vitamin K from last night’s dinner. That’s an important blood-clotting substance. And without the help of a neighboring microbe, the broccoli you downed would be no more digestible than a fallen log.

Right this minute, in the moist, warm grottos throughout your body, encounters with friendly bacteria are teaching your immune cells how to recognize dangerous invaders. The ability to distinguish friend from foe is crucial to keeping you healthy. And by acting as a thick ground cover, these benign bacteria crowd out truly noxious germs — salmonella, say, or dangerous versions of E. coli.

The title of NPR’s article is a bit misleading as the focus of the story is really on the potential harm from antibiotics. Bacterial Evolution in Yogurt provides some additional information on the benefits of bacteria. Here are more good bacteria articles:: Friendly bacteria ‘target ulcers’ – Over-sixties advised to boost daily diet with ‘good’ bacteria – USC researcher underscores the benefits bacteria can provide – Bacteria Added to Gum, Toothpaste and Deodorant – How ‘good’ bacteria could counter overuse of antibiotics

via: Take care of those microbes in your gut

Drug Resistant Bacteria More Common

Drug-resistant germs more common in USA by Anita Manning:

Drug-resistant bacteria that were rare just six years ago now are the most common cause of skin and soft-tissue infections treated in emergency rooms at 11 hospitals across the USA, a study finds.

Researchers at UCLA and the Centers for Disease Control and Prevention found that methicillin-resistant Staphylococcus aureus, or MRSA, accounted for 59% of skin infections overall, from 15% at a hospital in New York to 74% at one in Kansas City, Mo.

The finding suggests that doctors should consider drug resistance as a factor when diagnosing and treating skin infections, says Rachel Gorwitz of the CDC, a co-author of a study in today’s New England Journal of Medicine.

This is another sign of the increasing health threat posed by drug resistant bacteria. The problem of drug resistant bacteria is made much worse by the improper use of anti-biotics.

Antibiotic Resistance and You, Curious Cat Article
How do antibiotics kill bacteria?
More posts on antibiotics and bacteria

How do antibiotics kill bacteria?

How do antibiotics kill bacterial cells but not human cells? (pointy haired bosses (phb) at Scientific American broke the link so I removed it – see links in comments below that are not broken by phb behavior)

Most bacteria produce a cell wall that is composed partly of a macromolecule called peptidoglycan, itself made up of amino sugars and short peptides. Human cells do not make or need peptidoglycan. Penicillin, one of the first antibiotics to be used widely, prevents the final cross-linking step, or transpeptidation, in assembly of this macromolecule. The result is a very fragile cell wall that bursts, killing the bacterium.

Read more blog posts on antibiotics and on health care.

Entirely New Antibiotic Developed

Potent antibiotic to target MRSA

A potent antibiotic which kills many bacteria, including MRSA, has been discovered. Scientists with Merck, isolated platensimycin from a sample of South African soil and have developed an antibiotic based on that discovery.

If the compound passes clinical trials it will become only the third entirely new antibiotic developed in the last four decades.

Details in the journal Nature reveal the antibiotic works in a completely different way to all others.

It acts to block enzymes involved in the synthesis of fatty acids, which bacteria need to construct cell membranes.

Methicillin-resistant Staphylococcus Aureus (MRSA) is a type of bacteria that is resistant to certain antibiotics, including: methicillin and other more common antibiotics such as oxacillin, penicillin and amoxicillin. Staph infections, including MRSA, occur most frequently among persons in hospitals and healthcare facilities who have weakened immune systems. More information on MRSA is available from the United States Center for Disease Control and Prevention.

Wallaby Milk Cure

Fighting Superbugs with Milk

Cocks has found that the mother’s milk contains a molecule that is 100 times more effective against Gram-negative bacteria such as E. coli than the most potent form of penicillin. The molecule, called AGG01, also kills four types of Gram-positive bacteria and one type of fungus. The work was presented at the US Biotechnology Industry Organization 2006 meeting in Chicago last week.

Antibiotic Discovery Stagnates

Bad Bugs, No Drugs As Antibiotic Discovery Stagnates . . . A Public Health Crisis Brews by the Infectious Diseases Society of America. The site includes a 37 page white paper.

A multi-pronged approach is needed to limit the impact of antibiotic resistance on patients and the public. These efforts include educating physicians, patients, and parents about the appropriate use of antibiotics, developing and applying infection control and immunization policies and practices to prevent transmission, surveying clinical and prescription data, and developing safer alternatives to antibiotic uses in agriculture.

The purpose of this document, however, is to call attention to a frightening twist in the antibiotic resistance problem that has not received adequate attention from federal policymakers: The pharmaceutical pipeline for new antibiotics is drying up.

Facts About Antibiotic Resistance:

The total cost of antimicrobial resistance to U.S. society is nearly $5 billion annually, according to the Institute of Medicine (IOM). Treating resistant pathogens often requires more expensive drugs and extended hospital stays.

More on the overuse of antibiotics – which creates drug resistance
Previous posts on antibiotics

Are Antibiotics Killing Us?

Are Antibiotics Killing Us? by Jessica Snyder Sachs:

To counteract these killers, some physicians have turned to lengthy or lifelong courses of antibiotics. At the same time, other researchers are counterintuitively finding that bacteria we think are bad for us also ward off other diseases and keep us healthy. Using antibiotics to tamper with this complicated and little-understood population could irrevocably alter the microbial ecology in an individual and accelerate the spread of drug-resistant genes to the public at large.

Articles on the overuse of antibiotics.

Salyers says her research shows that decades of antibiotic use have bred a frightening

degree of drug resistance into our intestinal flora. The resistance is harmless as long as the bacteria remain confined to their normal habitat. But it can prove deadly when those bacteria contaminate an open wound or cause an infection after surgery.

Reducing Antibiotic Use

‘Natural’ chickens take flight by Elizabeth Weise

Four of the nation’s top 10 chicken producers have virtually ended a practice that health and activist groups for years charged was causing a public health crisis: feeding broiler chickens low doses of antibiotics to make them grow faster and stay healthy.

Tyson Foods, Gold Kist, Perdue Farms and Foster Farms say they stopped using antibiotics for growth promotion. In addition to ending a practice that Europe banned and McDonald’s ended a month ago, the four companies also have severely limited antibiotic use for routine disease prevention, though antibiotics are still used to treat disease outbreaks.

Are health groups against healthy chickens? No. They worry about the danger of creating resistance to antibiotics. Our past, and current, misuse of antibiotics is leading us to a future where our currently effective antibiotics will not be effective.

Tyson Foods, the nation’s largest chicken producer, has led the way with a 93% reduction, from 853,000 pounds in 1997 to just 59,000 in 2004. In 2004, less than 1% of the company’s broilers received antibiotics, says chief veterinarian Patrick Pilkington.

Perdue Farms stopped using antibiotics for growth promotion about five years ago. “It became obvious that it was a concern,” says chief veterinarian Bruce Stewart-Brown. Now at any given farm in the system, only one flock in five years receives antibiotics, either to halt a disease outbreak or because birds are threatened with infection, he says.

Positive steps to reducing our overuse of anti-biotics still leave us with much more to improve.

Evolution of Antibiotic Resistance

Inhibition of Mutation and Combating the Evolution of Antibiotic Resistance from the Public Library of Science Biology Journal:

The emergence of drug-resistant bacteria poses a serious threat to human health. In the case of several antibiotics, including those of the quinolone and rifamycin classes, bacteria rapidly acquire resistance through mutation of chromosomal genes during therapy. In this work, we show that preventing induction of the SOS response by interfering with the activity of the protease LexA renders pathogenic Escherichia coli unable to evolve resistance in vivo to ciprofloxacin or rifampicin, important quinolone and rifamycin antibiotics. We show in vitro that LexA cleavage is induced during RecBC-mediated repair of ciprofloxacin-mediated DNA damage and that this results in the derepression of the SOS-regulated polymerases Pol II, Pol IV and Pol V, which collaborate to induce resistance-conferring mutations. Our findings indicate that the inhibition of mutation could serve as a novel therapeutic strategy to combat the evolution of antibiotic resistance.