Antibiotic-resistant infections pose threat to human health

The Center for Disease Control and Prevention recently issued a landmark health report called “Antibiotic Resistance Threats in the United States, 2013.”

For the first time ever, the CDC has outlined a three-tiered ranking of the organisms by their threat to human health. They fall into the following categories: urgent, serious and concerning.

This health alert is warranted because deaths caused by super germs in the U.S. now outnumber deaths caused by car accidents. According to the CDC report, “more than

2 million people in the U.S. get infections that are resistant to antibiotics and at least 23,000 people die as a result.”

Consequently, national news frequently features stories involving multi-drug resistant (MDR) bacteria. Oct. 12 there was nationwide coverage of about 22 deaths this year in Florida from a deadly MDR bacteria called Vibrio Vulnificus. Its source was traced to salt water and raw shell fish. At the same time, the media announced that a third player with the Tampa Bay Buccaneers was diagnosed with methicillin-resistant Staphylococcus aureus (MRSA).

The CDC report states that “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 health care settings such as hospitals and nursing homes.”

Multi-drug resistant infections are assessed by seven factors: health impact, economic impact, how common the infection is, a 10-year projection of how common it could become, how easily it spreads, availability of effective antibiotics and barriers to prevention.

Among the infections classified as “urgent” threats include carbapenem-resistant Enterobacteriaceae (CRE), drug-resistant gonorrhea and Clostridium difficile. The latter is a serious diarrheal infection usually associated with antibiotic use, and it causes about 250,000 hospitalizations and at least 14,000 deaths per year in the U.S.

In the “serious” threat class are such bacteria as methicillin Staphylococcus aureus (MRSA) and nontyphoidal Salmonella infections.

Each year, 80,000 serious MRSA infections are reported in the U.S.

Among the class of “concerning” MDR infections includes group A Streptococcus, also known as “flesh-eating bacteria.”

These super germs have evolved with alarming speed as a byproduct of using antibiotics too often or inappropriately both in human consumption and in animals. The CDC states that up to 50 percent of all the antibiotics prescribed for people are “not needed or are not prescribed appropriately.”

Steve Solomon, M.D., director of CDC’s Office of Antimicrobial Resistance, said, “These drugs are a precious, limited resource – the more we use antibiotics today, the less likely we are to have effective antibiotics tomorrow.”

Another associated concern is that when people undergo surgeries such as total joint replacement, organ transplants, cancer therapy and rheumatoid arthritis therapy, they are often sent home with a prescription for a limited course of antibiotics.

Antibiotics

However, if “the ability to effectively treat those infections is lost,” the CDC report stated, “the ability to safely offer people many of the life-saving and life-improving modern medical advances will be lost with it.”

Combat ‘microbial nature’

The CDC has identified four core actions to combat this serious health threat:

1. Prevention of infections and their spread by immunizing, employing safe prevention in health care settings, using safe food preparation and handling and hand washing thoroughly with soap.

2. Tracking and surveillance by CDC. This involves learning the causes of infection and risk factors for patients presenting with MDR infections. This allows experts to develop defensive strategies to limit the spread of the MDR bacteria.

3. Improving antibiotic use and stewardship: Change the way antibiotics are used. Much of their current use is unnecessary, but when they are necessary, the CDC cautions to use them responsibly.

4. Developing Drugs and Diagnostic Tests: Since antibiotic-resistance is a natural process in which bacteria evolve, it can be slowed but not completely stopped. New antibiotics will always be needed to keep up with resistant bacteria. New tests will be needed to track the development of resistance.

Is there anything on the post-antibiotic horizon?

Possibly. American biologist and entrepreneur Craig Ventor, formerly associated with the National Institute of Health, founded his own research institute, the J. Craig Ventor Institute of Maryland in October 2006. He is one of the first to sequence the human genome, and is now looking at the genetic makeup of MDR bacteria.

At JCVI, he has organized a team of genome biologists trying to discover the genomic sequence of formidable MDR super germs to learn exactly why they resist antibiotic treatment.

The wheels of research turn slowly, and it has not met with a lot of success.

“There are ongoing projects to discover genomic sequencing of a diversity of Staphylococcus isolates to determine the genetic basis for drug resistance in S. Aureus (MRSA). To date, the sequencing of MRSA genomes has not yielded significant insights into the epidemiology of S. Aureus infections,” said the JCVI

website.

JCVI is also looking at the use of viruses as a treatment against MDR bacteria.

“We’re investigating something that was used in Eastern Europe before the discovery of penicillin – using viruses that kill bacteria, (called) bacteriophages, and coming up with new repertoires of those.”

Phage therapies have been used as treatments for more than 90 years in places like France, the former Soviet Union and some central European countries. It is being explored as a possible alternative therapy for treating (MDR) strains of many different kinds of bacteria.

The battle against the super germs will wage on. The question is can scientists slow the speed of natural microbial evolution so that they can remain one step ahead with effective treatments? CDC Director Dr. Tom Frieden thinks it is not too late.