The discovery and medical adaptation of antibiotics for disease control represents a significant medical advance.
The release of these approved drugs into the market for human health beginning in 1911 to the present, is impressive by any metric.
But widespread antibiotic resistance threatens the utility of these drugs, and human health.
This was recently reported by the Centers for Disease Control and Prevention (CDC).
All Americans should be aware of this emerging health threat.
A little background.
Different types or classes of antibiotics work in different ways.
All antibiotics are for killing, or inhibiting the growth and reproduction of, bacteria.
They do not work on other types of germs and are ineffective for treating viruses, for example.
Some antibiotics are bactereotoxic and kill the organisms with toxic substances.
Bacteria, unlike viruses, are living organisms, and are able to be killed this way.
Other classes of antibiotics target different parts of the bacteria in the inhibition of growth and reproduction, and are called bacteriostatic antibiotics.
Each antibiotic may have a specific target in the bacterium cell that it affects.
Bactereostatic antibiotics stop the ability of the bacteria to multiply.
This causes a weaker organism that is less severe infection to fight, and enables your own immune system to destroy the targeted bacterial invaders before you become too severely ill (and sometimes even before you have symptoms).
Antibiotic resistance is a form of drug resistance whereby some (or, less commonly, all) sub-populations of a microorganism, usually a bacterial species, are able to survive after exposure to one or more antibiotics.
Pathogens resistant to multiple antibiotics are considered multidrug resistant (MDR) or, more colloquially, superbugs.
Microbes, rather than people, develop resistance to antibiotics.
Antibiotic resistance is a serious and growing phenomenon in contemporary medicine and has emerged as one of the pre-eminent public health concerns of the 21st century.
This is particularly as it pertains to pathogenic organisms (the term is especially relevant to organisms which cause disease in humans).
In the simplest cases, drug-resistant organisms may have acquired resistance to first-line antibiotics, thereby necessitating the use of second-line agents.
Typically, a first-line agent is selected on the basis of several factors including safety, availability and cost; a second-line agent is usually broader in spectrum, has a less favorable risk-benefit profile and is more expensive or, in dire circumstances, be locally unavailable.
In the case of some MDR pathogens, resistance to second and even third-line antibiotics is thus sequentially acquired, a case quintessentially illustrated by Staphylococcus aureus in some hospital settings.
Some pathogens, such as Pseudomonas aeruginosa, also possess a high level of intrinsic resistance.
It may take the form of a spontaneous or induced genetic mutation, or the acquisition of resistance genes from other bacterial species by horizontal gene transfer via conjugation, transduction, or transformation.
Many antibiotic resistance genes reside on transmissible plasmids, facilitating their transfer.
Exposure to an antibiotic naturally selects for the survival of the organisms with the genes for resistance.
In this way, a gene for antibiotic resistance may readily spread through an ecosystem of bacteria.
Antibiotic-resistance plasmids frequently contain genes conferring resistance to several different antibiotics.
Genes for resistance to antibiotics, like the antibiotics themselves, are ancient.
However, the increasing prevalence of antibiotic-resistant bacterial infections seen in clinical practice stems from antibiotic use both within human medicine and veterinary medicine.
Any use of antibiotics can increase selective pressure in a population of bacteria to allow the resistant bacteria to thrive and the susceptible bacteria to die off.
As resistance towards antibiotics becomes more common, a greater need for alternative treatments arises.
However, despite a push for new antibiotic therapies there has been a continued decline in the number of newly approved drugs.
Antibiotic resistance therefore poses a significant problem.
The growing prevalence and incidence of infections due to MDR pathogens is epitomized by the increasing number of familiar acronyms used to describe the causative agent and sometimes the infection generally.
A few (of the many) prominent examples follow:
- MRSA - methicillin-resistant S. aureus
- VISA - vancomycin-intermediate S. aureus
- VRSA - vancomycin-resistant S. aureus
- ESBL- extended spectrum beta-lactamase
- VRE - Vancomycin-resistant Enterococcus
- MRAB - multidrug-resistant A. baumannii
Antibiotic resistant bacterial infections lead to serious health problems.
Each year in the United States, at least 2 million people become infected with bacteria that are resistant to antibiotics and at least 23,000 people die each year as a direct result of these infections.
Many more people die from other conditions that were complicated by an antibiotic-resistant infection.
Antibiotic-resistant infections can happen anywhere.
Data show that most happen in the general community; however, most deaths related to antibiotic resistance happen in healthcare settings such as hospitals and nursing homes.
Hospital-acquired infections overwhelmingly dominate cases where MDR pathogens are implicated, but multidrug-resistant infections are also becoming increasingly common in the community.
A recent report from the CDC on antibiotic resistance is worth review.
It is the report entitled Antibiotic Resistance Threat in the United States, 2013.
Noteworthy is its summary of the problem.
"Antibiotic-resistant infections add considerable and avoidable costs to the already
overburdened U .S . healthcare system .
In most cases, antibiotic-resistant infections require prolonged and/or costlier treatments, extend hospital stays, necessitate additional doctor visits and healthcare use, and result in greater disability and death compared with infections that are easily treatable with antibiotics .
The total economic cost of antibiotic resistance to the U .S . economy has been difficult to calculate . Estimates vary but have ranged as high as $20 billion in excess direct healthcare costs, with additional costs to society for lost productivity as high as $35 billion a year (2008 dollars).
The use of antibiotics is the single most important factor leading to antibiotic resistance
around the world .
Antibiotics are among the most commonly prescribed drugs used in human medicine .
However, up to 50% of all the antibiotics prescribed for people are not needed or are not optimally effective as prescribed ."
Also noteworthy is the finding that the use of antibiotics as food animal growth promotants contributes to production of antibiotic resistant microbes infecting humans.
"Antibiotics are also commonly used in food animals to prevent, control, and treat disease, and to promote the growth of food-producing animals. The use of antibiotics for promoting growth is not necessary, and the practice should be phased out . "
For a long time, low levels of antibiotics have given to certain farm animals to accelerate growth. These are termed "growth promotants."
The CDC report concludes that such use contributes to generation of antibiotic resistant microbes that threaten human health.
"Antibiotics are widely used in food-producing animals, and according to data published
by FDA, there are more kilograms of antibiotics sold in the U.S. for food producing animals than for people."
This use contributes to the emergence of antibiotic-resistant bacteria in food-producing animals .
Scientists around the world have provided strong evidence that antibiotic use in food producing animals can harm public health through the following sequence of events:
- Use of antibiotics in food-producing animals allows antibiotic-resistant bacteria to thrive while susceptible bacteria are suppressed or die .
- Resistant bacteria can be transmitted from food-producing animals to humans through the food supply.
- Resistant bacteria can cause infections in humans .
- Infections caused by resistant bacteria can result in adverse health consequences for humans."
The problem in antibiotic resistance impacts all Americans.
This CDC report is worth review.