The Post Antibiotic Era? Why Antimicrobial Stewardship is Critical for the Future of Infectious Disease Prevention .

 

When-Life-Gives-You-Mold-Make-Penicillin_1899-lSome clinical epidemiologists (myself included) have suggested that a general disregard exists in surveillance and monitoring when it comes to medical and health practitioner staff concerning follow-up with patients diagnosed with an infectious antigen, and moreover, the handling of disinfection of infected surfaces and garments. While there is a sense of protection due to the availability of vaccines and antibiotics, there is an illusion that health staff and practitioners have the requisite knowledge to ensure patient adherence to prescribed treatments, the necessary follow-up is often insufficient to prevent reinfection.

Penicillin: The wonder drug. After returning from a vacation Alexander Fleming was cleaning up his running experiments including some petri dishes containing staphylococcus bacteria. He noticed something odd on one dish; it had sprouted a small colony of mold. He also noticed that they bacteria were avoiding the area around the mold. Fleming later identified the mold as a real strain of Penicillin Notatum, and it seemed as though the mold was preventing the bacteria from growing. Further experimentation by Fleming found that penicillin was capable of killing a number of harmful bacteria known that time, however it would be a number of years before penicillin could be refined and used as a treatment. Nevertheless, what would become the first wonder drug had been discovered purely by accident. Over the following 25 years, penicillin would become highly effective at treating a number of bacterial infections. However, its effectiveness today is drastically being reduced, as are many antibiotics.

Bacteria become resistant through overuse and misuse. When prescribed an antibiotic for a cold, influenza, sore throat, bronchitis, many sinus infections or any other viral infection, the antibiotic does nothing to treat the illness but instead destroys helpful bacteria in the body. Another overuse of antibiotics is in the livestock meat industry. Livestock producers give antibiotics to farm animals to make them grow faster, help them survive crowded stressful and unsanitary conditions. It has been estimated that 70% to 85% of all antibiotic use is in livestock meat industry. You maybe asking yourself, how does overuse or misuse lead to antibiotic resistance? If an antibiotic effective, doesn’t it remain effective? Bacteria are living things, and as such follow much the same processes as higher organisms including mutation and evolution.

AR-cdc2017

Conjugation: bacteria can acquire antibiotic resistance genes from other bacteria in several ways. By undergoing a simple mating process called “conjugation,” bacteria can transfer genetic material, including genes encoding resistance to antibiotics (found on plasmids and transposons) from one bacterium to another.

Bacterial conjugation is the transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells. It is a mechanism of horizontal gene transfer, as are transformation and transduction (although these two other mechanisms do not involve cell-to-cell contact). During conjugation, the donor cell provides genetic material (plasmid or transposon), and most conjugative plasmids have systems ensuring that the recipient cell does not already contain a similar element (eliminating duplication and ensuring enhancement). These enhancements may include antibiotic resistance, xenobiotic tolerance, or the ability to metabolize small molecules for energy, thus the foundation of a newer, more resilient bacterium.

AR-CDC 2017Evolution: the same natural forces that have produced every species on the planet benefit a bacterium. The term survival of the fittest is even more evocative of bacteria, as their “life-cycles” are short, and are measured in hours. Bacteria don’t have a life span, and a bacterial age is the period up to cell division, which can be from a few minuets to several hours (or many years on inanimate surfaces such as rock), and is unlimited by the mode or reproduction (asexual). Just as a microorganism evolves very slightly with each new generation, often taking hundreds of thousands of years (think of the Galapagos Finches), and because bacteria reproduce so quickly, they evolve at a significantly faster rate than longer-lived organisms. In any population, whether we are talking about finches or bacterium, there are many genes present within the population that express in a variety of ways, and the traits of these genes our mixed.

Like the finches discovered by Charles Darwin in the Galapagos Islands, the original decedents found themselves in a new, challenging environment, and were forced to adapt to the environment (this is referred to as a selective pressure), and evolved to survive in their new surroundings. Over thousands of years, new varieties emerged from the original population to take advantage of the environment. If we speed this up thousands of times, we can see how bacteria react in much he same way to environmental pressures.

Adaptation: while we certainly would not suggest that bacteria think, they certainly have developed adaptations. When this bacterium is exposed to a toxin (anti-bacterial), the vast majority is killed. But a very small number, through a fluke of genetic recombination from the many genes present allows them to survive. These few are now able to reproduce, and when they divide, their descendants naturally inherit the same resistance. Over time, due to the rapid lifecycles of bacteria, a new resistant strain evolves. Researchers are finding that when stressed by repeated cycles of antibiotic treatment, some bacteria can evolve and adapt for more quickly then imagined, in some cases within a few days, and seem to be able to suspend their “G time” (a period of little or no growth) to help it survive antibiotics. This is really bad news for patients who have compromised immune systems which are susceptible to opportunistic infections through immune dysfunction or immune suppressant therapies.

When a bacterium becomes resistant to the antimicrobial treatments that have historically been used, it becomes significantly harder to treat. These resistant forms of bacteria fall into a set of Hazard categories depending on factors including the seriousness of infection and difficulty in treatment.

Urgent Concern includes Clostridium difficile (C-Diff), Carbapenem-resistant Enterobacteriaceae (CRE) and Neisseria Gonorrhea (resistant to cephalosporin).

Serious Concern includes Multi-drug Resistant Aceinetobacter, Drug Resistant Campylobacter, Multi-drug Resistant Pseudomonas Aerugionosa, Drug-resistant Shigella, Vancomycin-resistant Enterococcus (VRE), Methicillin-resistant Staphylococcus Aureus (MRSA), Drug- resistant Streptococcus Pneumonia, at least one form of Drug-resistant Tuberculosis, and two forms of Drug-resistant Salmonella.

Growing concern includes Vancomycin-resistant Staphylococcus Aureus, Erythromycin-resistant Group A Strep, and Clindamycin-resistant Group B Strep.

handwashing-poster-small1

What can you do to protect your family?

Think like an epidemiologist: start with hand washing; this is your best defense against infections that cause diarrheal and respiratory illnesses. Regular hand washing after certain activities is the best ways to remove viruses and bacteria and avoid spreading them to others.

Stay Up-to-Date with Vaccines: Prevention is key to staying healthy. It is always easier and better to prevent disease than to try to treat it. Vaccines are responsible for the control of many infectious diseases that were once common, including polio, measles, diphtheria, pertussis, rubella, mumps, and tetanus. Since their introduction, vaccines have prevented countless cases of infectious diseases and saved millions of lives.

Prevent the Spread of Food borne Infections: keeping your water safe and clean will help you from preventing waterborne illnesses from occurring, including bacteria (and a few nasty parasites).

Never take an antibiotic for an infection like a cold or flu and never try to pressure your healthcare provider into prescribing an antibiotic.

Do not save antibiotics and never take antibiotics prescribed for someone else.

 

In the end, each of us must be responsible for our preventative health, and overuse of antibiotics in prescribing and food animals will continue to threaten public health. But there are some steps we can take to avoid these infections. Antimicrobial stewardship has become a significant aspect of public health, and each of us must do our part.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s