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MRSA and Drug-Resistant Microbes


Superbugs and antibiotic resistance are catchphrases we hear often in the news. It can be hard to parse the hype from the actual harm. Here, we take a look at antibiotic resistance, how bacteria have evolved to be able to block our most powerful medicines, and what this means for medical care today. We'll also look at how the Yale Medicine Laboratory Medicine Department is staying at the forefront of this urgent global issue.

What are microbes?

Microbes are living organisms that are so small that they can only be seen under a microscope and not by the naked eye. Microbes are broken into six main groups, including bacteria and viruses. Most do us no harm. In fact, humans could not survive without them. However, some microbes cause disease. 

"These bugs are fascinating on multiple levels," says Yale Medicine pathologist David Peaper, MD, PhD. "They've been evolving for millions of years, and they continue to evolve, right before our eyes. Every day something new happens – something we haven't seen before."

What are drug-resistant microbes?

Over time, bacteria can change and build up defenses that block the effects of antibiotics, such as penicillin, a common medicine used to fight bacterial infections. Antibiotics are designed to inhibit the growth of, or destroy, microorganisms, especially fungi or bacteria, that lead to infectious disease and infections.

However, the overuse of antibiotics during the past three decades in people and livestock has led to the development of superbugs, which most antibiotic drugs cannot treat. This is because the microbes have evolved to outsmart the drugs. 

What are the potential harms of drug-resistant microbes?

Before the arrival of antibiotics, if a person experienced a cut to the skin or similar minor injury, the chances of a serious infection or death were high. In the 1950s and 60s, about 150 classes of antibiotics were introduced, and these were heralded as miracle drugs.  

However, in the intervening years, as antibiotics have been frequently prescribed, some bacteria and fungi have developed resistance to them. This is worrisome on many levels.

More than 2.8 million infections and 35,000 deaths in the United States each year are attributed to antibiotic-resistant bugs. Those numbers have been increasing in recent years.  

"The big concern emerged in the past few years as resistance began to spread, being transferred from bug to bug, and from patient to patient," Dr. Peaper says.  "It really is quite concerning. Antibiotics are what made much of modern medicine, things such as surgery, possible."

What are some examples of drug-resistant infections?

Arguably the most widely known drug-resistant infections is methicillin-resistant Staphylococcus aureus or MRSA. This resistant infection is often associated with hospitals. Others you may have heard of include C.diff (clostridium difficile), drug-resistant malaria and streptococcus pneumoniae

How does Yale Medicine evaluate drug-resistant microbes?

Scientists at Yale Medicine process hundreds of thousands of specimens, more than any one doctor could ever see on the hospital rounds, Dr. Peaper says. 

This specimen archive and knowledge informs cases encountered by infectious disease, epidemiology and pharmacy colleagues, which leads to patients receiving the best possible care. Together, the Yale Medicine powerhouse team works to identify any potential outbreak of drug-resistant bacteria. 

"We have the numbers, the expertise and the relationships with colleagues in other disciplines to get to the bottom of what's causing infection and to work toward containing it," says Dr. Peaper. 

Yale Medicine's labs also serve as a trusted reference point for medical centers and hospitals in its geographic region. The lab also takes part with state and federal groups, when needed, to evaluate resistant organisms.

What makes Yale Medicine’s approach to drug resistant microbes unique?

Yale Medicine's labs can provide definitive susceptibility test results as quickly as possible, to identify organisms quickly and narrow treatment. This means fewer patients needlessly taking antibiotics, and cutting down on the antibiotic overuse that is a contributing factor to antibiotic resistance.