For millions in the United States, the onset of “nightmare bacteria” has adversely changed their lives. With at least 2 million infected and at least 23,000 people dying every year due to antibiotic-resistant bacterial, the Centers for Disease Control and Prevention (CDC) has stated in a new report that the difficult-to-treat bacteria «pose a catastrophic threat» to every nation on the planet.
“Antimicrobial resistance is one of our most serious health threats,” states the report, which continues:
Infections from resistant bacteria are now too common, and some pathogens have even become resistant to multiple types or classes of antibiotics (antimicrobials used to treat bacterial infections). The loss of effective antibiotics will undermine our ability to fight infectious diseases and manage the infectious complications common in vulnerable patients undergoing chemotherapy for cancer, dialysis for renal failure, and surgery, especially organ transplantation, for which the ability to treat secondary infections is crucial.
This report represents the first governmental attempt to quantify the annual rate of infection due to bacteria that have become resistant antibiotics due to overuse in animals and humans. The CDC estimates that antibiotic resistance is adding $20 billion in excess, direct healthcare costs in the United States and costs the nation as much as $35 billion per year in lost revenue.
What is antibiotic resistance?
Antibiotic resistance is actually a proof of the mechanisms of evolution. Large bodies of bacteria are exposed to an antibiotic, which effectively kills off enough of the microbes to make the affected area or person sterile of the targeted microorganism. Sterilization, however, does not mean that every single targeted bacteria was killed. Typically, sterilization is felt to have occurred when a high sterility assurance level — or the actual reduction in bacterial colony, usually a reduction to 0.0000001 the size of the original — has been achieved. The surviving microbes contain genetic mutations that render the microbes — at least in part — chemically resilient to the antibiotic.
Repeat cycles of growth and exposure to the antibiotic will eventually lead to the proliferation of a genetically mutated strain that is predominantly resistant to the antibiotic. As every exposure to the antibiotic “thins the herd” — leaving behind increasingly more resistant microbes to create the next generation — overuse of an antibiotic creates a situation in which a strain of bacteria is not only resistant to a known antibiotic, but may be partially or fully resistant to an entire class of antibiotics.
Bacteria are also subject to horizontal gene transfer, or the transfer of gene segments from one bacterium to another via viral transmission or the uptake and expression of free RNA strands. This form of mutation can radically shorten the evolutionary cycle of a resilient strain.
The CDC estimates that almost half of all antibiotic use in humans is unnecessary. Dr. Tom Frieden, the director of the CDC and the lead author of the report, attributes this to the notion that many think of antibiotics as needed for disease eradication and insisting on them — even when they are not needed.
“Every time antibiotics are used in any setting, bacteria evolve by developing resistance. This process can happen with alarming speed,” said Steve Solomon, M.D., director of the CDC’s Office of Antimicrobial Resistance. “These drugs are a precious, limited resource — the more we use antibiotics today, the less likely we are to have effective antibiotics tomorrow.”
A contaminated food supply
At least 70 percent of all antibiotics in the United States are used agriculturally to promote livestock growth and prevent the spread of diseases in feedlots, where animals tend to be in close physical contact with each other for prolonged periods of time. The antibiotics — which are absorbed into animals’ musculature — and the resistant bacteria strains the animal may be carrying are passed to humans via direct consumption of meat harvested from the animals or from farm-grown crops that were fertilized using manure from the animals.
Typically, antibiotics are given in repeated low doses to prevent stress to the animal. This kind of dosing provides an ideal situation for rapid bacterial evolution and disassociation with the antibiotic.
There is also a risk that feed, made in part from antibiotics-treated animals and fed to other antibiotics-treated animals, may form antibiotic-resilient strains in the farm animals. «Widespread use of antibiotics in agriculture has resulted in increased resistance in infections in humans,» Frieden said.
The livestock industry disputes this. The Animal Health Institute, a lobbying group that represents pharmaceutical companies, states:
Of the 18 specific antibiotic-resistant threats discussed in the report, only two have possible connections to antibiotic use in food animals. … Antibiotic resistance is an important public health threat that animal drug sponsors, veterinarians and food producers take seriously. Antibiotics used in food animals receive intense scrutiny before they are approved by FDA. Once approved, use is scrutinized through programs intended to protect public health, including the National Antimicrobial Resistance Monitoring Program and the U.S. Department of Agriculture’s residue testing program.
«We constantly hear from the pharmaceutical and livestock industry that antibiotic use in livestock is not a problem and we should focus on human use,» said Avinash Kar, a staff attorney at the San Francisco office of the Natural Resources Defense Council, who has sued the FDA to force it to ban the use of antibiotics to promote growth in livestock. The case is now pending before the 2nd U.S. Circuit Court of Appeals. A number of Democrats in Congress — including Rep. Louise Slaughter (D-N.Y.) and Sens. Dianne Feinstein (D-Calif.) and Kirsten Gillibrand (D-N.Y.) — have attempted to ban antibiotic use in livestock, only to have their efforts fail after lobby-heavy pushbacks.
Failures in the system
In its report, the CDC admits there are areas where a lack of knowledge or a lack of impetus have exacerbated the danger of the antibiotic-resistance menace. Limited national and state capability to identify and respond to threats, a failure to systematically account for healthcare and agricultural use of antibiotics; a lack of widespread implementation of improved antibiotic prescribing and a lack of use of available technology are all contributing to the problem.
However, the most immediate correction that can be taken to mitigate antibiotic resistance lies with the nation’s hospitals. “[Right] now the really most acute problem is in hospitals,” Frieden said. “And the most resistant organisms in hospitals are emerging in those settings, because of poor antimicrobial stewardship among humans.”
Of particular concern for patients of healthcare facilities is the spread of carbapenem-resistant Enterobacteriaceae (CRE), which is resistant to almost all antibiotic treatments currently known. Nearly half of all hospital patients that contract a bloodstream CRE infection will die as a result. While bloodstream infections only make up a small minority of all CRE cases — roughly 9,300 per year — about 600 people die each year from carbapenem-resistant Klebsiella spp. and carbapenem-resistant E. coli, the two most common CRE strains.
In addition, Clostridium difficile infections are also on the rise, causing 250,000 infections in the U.S. per year requiring hospitalization or — overwhelmingly — affecting the already hospitalized. The disease, which affects those with weakened immune systems after heavy antibiotics use or invasive medical treatment, causes life-threatening diarrhea, killing around 14,000 every year and increasing medical costs by more than $1 billion per year. Of those infected, 90 percent are over the age of 65.
Human-to-human contact has proven key to the transmission of this and other antibiotic-resistant infections. Improper sanitation, including the failure to wash hands after using the lavatory, failure to properly disinfect and sanitize surfaces with a cellular-disintegrating solution such as bleach, failure to treat diarrhea by,ensuring that sick patients use a separate or well-cleaned toilet, and the failure to track and report outbreaks have led to the proliferation of the infections.
“[Infections] … that are ranked as concerning include bacteria such as drug-resistant streptococcus, which is the cause of the so called flesh-eating bacteria, and leading cause of serious bacterial infections in newborns.,” Frieden said. “Without urgent action now, more patients will be thrust back to a time before we had effective drugs. We talk about a pre-antibiotic era and an antibiotic era. If we’re not careful, we will soon be in a post antibiotic era. And, in fact, for some patients and some microbes, we are already there.”