Evolving bacteria:

Filed under: Uncategorized | Tags:

When penicillin became widely available during the Second World War, it was a medical miracle, quickly overcoming the biggest wartime killer — infected wounds. But within four years after drug companies began mass-producing penicillin in 1943, resistant microbes began to appear.
Since 1947, scores of antibiotics have been introduced by drug companies and every one has been compromised by resistant bacteria.
The process by which bacteria acquire drug resistance is a textbook example of evolutionary biology. Any population of organisms, bacteria included, includes variants with unusual traits — in this case, the ability to withstand an antibiotic’s attack on a microbe. When a person takes an antibiotic, the drug kills the non-resistant bacteria, leaving behind – or “selecting,” in biological terms – those that can resist it. These remnant bacteria then multiply and, increase their numbers a millionfold in a day, becoming the predominant microorganism.
Until the early 1980s, pharmaceutical companies stayed ahead of the rapidly evolving bacteria, bringing newer and more powerful antibiotics to the marketplace. In 1969, the U. S. surgeon general confidently asserted that “the war on infectious disease has been won.”
He was wrong.
The last 20 years has seen the emergence of a frightening class of superbugs, or multi-drug resistant organisms (MDROs). These microbes, including methicillin-resistant staphylococcus aureus (MRSA), multi-drug resistant tuberculosis (MDRTB) and vancomycin-resistant enterococci (VRE), are often found in hospital settings. They have been responsible for severe, persistent, difficult to treat and sometimes fatal infections.
In 1974, MSRA infections accounted for only 2 percent of the most common form of staph infections found in hospitals; today the number is more than 60 percent. This year, nearly 2 million Americans will get bacterial infections while in a hospital; 90,000 will die. MDROs are implicated in many of these deaths, particularly those involving elderly patients or those with weakened immune systems.
But even young, healthy patients, who might be in a hospital for a minor outpatient procedure, are at risk.
Does the solution lie in the development of new antibiotics? If so, they’re not coming from big pharmaceutical companies. Only 13 new antibiotics have reached the market since 1998. That might be because drug companies largely abandoned research on antibiotics during the 1980s in favor of developing highly profitable “blockbuster” drugs for conditions such as depression and high cholesterol.
Rather than waiting for new antibiotics to come to market, and begin the whole cycle anew, the hospitals that have been the breeding grounds of MDROs are beginning to examine their own practices.
American hospitals have been slow to recognize the perils of MDROs. Until fairly recently, few hospitals had adopted the rigorous protocols, common in Europe, that are known to inhibit the spread of such organisms.
But that’s changing. As Dr. Jane Siegel wrote last year in Management of Multidrug-Resistant Organisms In Healthcare Settings: “ The prevention and control of MDROs is a national priority – one that requires that all health care facilities and agencies assume responsibility.”
Several European countries, led by the Netherlands and Finland, have effectively eliminated MRSA through screening and isolation of patients, along with a relentless focus on hygiene. But at many American hospitals high infection rates have been accepted as a cost of doing business. Less than a quarter of American hospitals screen patients for resistant bacteria in any methodical way, according to the federal Centers for Disease Control and Prevention.
The price of such indifference is high, both to patients and to hospitals. According to the Committee to Reduce Infection Deaths, an organization headed by former New York Lt. Gov. Betsy McCaughey, “…studies show that nearly three-quarters of patients’ rooms are contaminated with MRSA and 69 percent with VRE. In one study, 42 percent of gloves worn by hospital personnel who had no direct patient contact, but who touched contaminated surfaces, became contaminated.”
McCaughey believes that three steps can dramatically cut infection deaths in hospitals: meticulous hand-washing between procedures, cleaning equipment between patient use and identifying infected people before they enter the hospital.
Thanks to de facto federal mandates, hospitals which fail to control infections will be penalized. During August, Medicare announced that it would no longer cover the cost of treating hospital-acquired infections, placing the burden of such treatment directly upon health care facilities.
In Colorado Springs, Memorial Health Systems, which operates two hospitals, has a program to reduce, and eventually eliminate, hospital-acquired infections.
Lynn Baldvins, Memorial’s infection prevention program manager, confirmed that Memorial complies with, and even goes beyond, RID’s “15 steps.” For instance, while RID recommends that hospitals use antibiotic-impregnated central catheter lines, Memorial has found that using chlorhexidine, as well as using a chlorhexidine-impregnated patch to prevent the migration of bacteria up the line, has had far better results.
Baldvins said that new antibiotics aren’t the answer.
“We’ll just see new resistant bacteria. We (hospitals) need to manage and reduce the risks of MRSA and VRE. We need to be antibiotic stewards — to use them sparingly, and not to always use the most powerful one, but the most effective one for a particular condition.”
But, she said, resistant antibiotics are not just confined to hospitals.
“We’re seeing lots of patients coming in who have MRSA infections that they contracted in the community — parents bring in their child, and they think it’s a spider bite, but it isn’t. These are dangerous things, and they have to be treated promptly.”
Baldvins agrees that hospitals have a strong financial incentive to reduce infection rates, but, she said, that’s not the point.
“We do it because it’s right,” she said. It’s what benefits our patients, and that’s why we’re here.”
John.Hazlehurst@csbj.com